WO2017208078A1

WO2017208078A1 - Communication method, terminal device and network device

Info

Publication number: WO2017208078A1
Application number: PCT/IB2017/000814
Authority: WO
Inventors: Pingping Wen; Tao Yang; Yuchu Ma
Original assignee: Alcatel Lucent
Priority date: 2016-05-31
Filing date: 2017-05-16
Publication date: 2017-12-07
Also published as: CN107454677A; CN107454677B

Abstract

Embodiments of the present disclosure relate to a communication method, a terminal device and a network device. Embodiments of the present disclosure provide a communication method implemented at terminal device, comprising: establishing a first connection between the terminal device and a first network device at least for use in control plane transmission for the terminal device; establishing connections between the terminal device and network devices in a network device cluster; and in response to a second network device in the network device cluster being selected as a serving network device for the terminal device, performing data plane transmission for the terminal device via a second connection between the terminal device and the second network device. According to solutions of embodiments of the present disclosure, a flexible network system and a fast and reliable mobility scheme can be provided by considering properties such as likelihood to blockage of MMW physical channel and high-gain beamforming of the MMW network using multiple antennas.

Description

COMMUNICATION METHOD, TERMINAL DEVICE

AND NETWORK DEVICE

FIELD

[0001] Embodiments of the present disclosure relate to the field of wireless communications, and more specifically to communication methods respectively implemented at a terminal device and a network device, a terminal device and a network device.

BACKGROUND

[0002] At present, the 5^th generation mobile communication (5G) technology becomes a research hotspot in the industry. In respect of wireless spectrum, efforts are being positively made to use high-frequency band such as mm-wave (MMW) band in wireless communication.

[0003] Especially, 5G wireless/mobile access is expected to use MMW frequencies to provide multi-Gbps data rates. The high frequencies of MMW signals result in high pathloss and the small wavelengths of these signals also enable large number of antenna elements to be placed in the same physical area, thereby providing high beamforming gains. Furthermore, due to the higher path loss of a MMW link, it is assumed that the density of the MMW base station is much higher than for Long Term Evolution (LTE) link in lower band, and that a mobile station will require more frequently a handover procedure in the MMW band than in the LTE band. In addition, the MMW link will more easily be blocked by the movement of vehicles and users.

[0004] Due to the above features of the MMW link and MMW network, it is necessary to define a flexible network system and a fast and reliable mobility scheme to serve the MMW user considering the features of the MMW physical channel with high beamforming gains and likelihood to blockage.

SUMMARY

[0005] On the whole, embodiments of the present disclosure provide communication methods respectively implemented at a terminal device and a network device, a terminal device and a network device. [0006] In an aspect, embodiments of the present disclosure provide a communication method implemented at a terminal device. The method comprises: establishing a first connection between the terminal device and a first network device at least for use in control plane transmission for the terminal device; establishing connections between the terminal device and network devices in a network device cluster; and in response to a second network device in the network device cluster being selected as a serving network device for the terminal device, performing data plane transmission for the terminal device via a second connection between the terminal device and the second network device.

[0007] In this aspect, embodiments of the present disclosure further provide a terminal device. The terminal device comprises: a processor, and a memory, the memory storing an instruction, the instruction, when is run by the processor, enabling the terminal device to implement the method according to this aspect.

[0008] In another aspect, embodiments of the present disclosure provide a communication method implemented at a first network device. The method comprises: establishing a first connection between the first network device and a terminal device at least for use in control plane transmission for the terminal device; and sending to the terminal device configuration information about a network device cluster so that the terminal device establishes connections with network devices in the network device cluster based on the configuration information and performs data plane transmission for the terminal device by using a second connection with a second network device in the network device cluster selected as a serving network device.

[0009] In this aspect, embodiments of the present disclosure further provide a network device. The network device comprises: a processor, and a memory, the memory storing an instruction, the instruction, when is run by the processor, enabling the network device to implement the method according to this aspect.

[0010] According to a further aspect of embodiments of the present disclosure, there is provided a communication method implemented at a second network device, the second network device belonging to a network device cluster. The method comprises: establishing a connection between the second network device and a terminal device; in response to the second network device being selected as a serving network device for the terminal device, performing data plane transmission for the terminal device via the connection established between the second network device and the terminal device. [0011] In this aspect, embodiments of the present disclosure further provide a network device. The network device comprises: a processor, and a memory, the memory storing an instruction, the instruction, when is run by the processor, enabling the network device to implement the method according to this aspect. [0012] According to solutions of embodiments of the present disclosure, a flexible network system and a fast and reliable mobility scheme with respect to properties such as high beamforming gain and likelihood to blockage of a MMW physical channel.

[0013] It will be appreciated that the Summary part does not intend to indicate essential or important features of embodiments of the present disclosure or to limit the scope of the present disclosure. Other features of the present disclosure will be made apparent by the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Through the following detailed description with reference to the accompanying drawings, the above and other features, advantages and aspects of example embodiments of the present disclosure will become more apparent. In the drawings, identical or similar reference numbers represent the same or similar elements, in which:

[0015] Fig. 1 is a diagram illustrating a network system according to an embodiment of the present disclosure;

[0016] Fig. 2 is a diagram illustrating a communication procedure of a network system according to an embodiment of the present disclosure;

[0017] Fig. 3 is a diagram illustrating a network system with a movement of a terminal device according to an embodiment of the present disclosure;

[0018] Fig. 4 is a flow chart of a communication method implemented at a terminal device according to an embodiment of the present disclosure; [0019] Fig. 5 is a flow chart of a procedure of determining a network device cluster implemented at the terminal device according to an embodiment of the present disclosure;

[0020] Fig. 6 is a flow chart of a procedure of selecting a serving network device implemented at the terminal device according to an embodiment of the present disclosure;

[0021] Fig. 7 is a flow chart of a communication method implemented at a first network device according to an embodiment of the present disclosure; [0022] Fig. 8 is a flow chart of a communication method implemented at a second network device according to an embodiment of the present disclosure;

[0023] Fig. 9 is a diagram illustrating an information interacting and processing procedure according to an embodiment of the present disclosure; [0024] Fig. 10 illustrates a block diagram of an apparatus implemented at a terminal device according to an embodiment of the present disclosure;

[0025] Fig. 11 illustrates a block diagram of an apparatus implemented at a first network device according to an embodiment of the present disclosure;

[0026] Fig. 12 illustrates a block diagram of an apparatus implemented at a second network device according to an embodiment of the present disclosure; and

[0027] Fig. 13 illustrates a block diagram of a device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0028] Embodiments of the present disclosure will be described with reference to the drawings in detail. Though some embodiments of the present disclosure are shown in the drawings, it should be appreciated that the present disclosure can be implemented in various manners and should not be interpreted as limited to the implementations described herein. Conversely, these implementations are provided for thorough and complete understanding of the present disclosure. It is to be understood that the drawings and implementations are only for the purpose of example, rather than to limit the scope of protection of the present disclosure.

[0029] The term "a first network device" used herein refers to a network device based on LTE transmission and is hereinafter referred to as LTE network device. As an example, the LTE network device may include a node B (NodeB or NB), an evolved node B (eNodeB or eNB), a remote radio unit (RRU), a radio frequency head (RH), a remote radio head (RRH), a relay, or a low power node such as a femto station and a pico station and the like.

[0030] The term "a second network device" used herein refers to a network device based on MMW transmission and is hereinafter referred to as MMW network device. For example, MMW network device may include any MMW transmission-based nodes to be developed in the future. [0031] The term "user equipment (UE)" used herein refers to any terminal device that can perform wireless communication with network devices or with each other. As an example, the terminal device may include a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), a mobile station (MS), or an access terminal (AT) and the above vehicle-mounted devices.

[0032] As used herein, the term "includes" and its variants are to be read as open-ended terms that mean "includes, but is not limited to." The term "based on" is to be read as "based at least in part on." The term "one example embodiment" is to be read as "at least one example embodiment," and the term "another embodiment" is to be read as "at least one another embodiment." Relevant definition for other terms will be given in the following depiction.

[0033] As stated above, an MMW physical channel has a property of easily being blocked. In view of this, if the MMW base stations are deployed stand-alone and all links operate on the MMW link, there will exist the above issues such as the high density of MMW base stations which will cause the frequent handover and the MMW link which is easily to be blocked. Therefore a solution to support multiple connections with the LTE link and MMW links should be used. The LTE link is used for the control plane management and both the LTE link and MMW links can be used for data transmission. The dual connectivity concept has been defined in Release 12 of Third Generation Partnership Project (3GPP R12). But the dual connectivity concept is not suitable for the dual connectivity of the MMW links and LTE link as the following:

[0034] First, dual connectivity in 3GPP only support the connection of two links, i.e., one connection with MeNB (main eNB, main evolved NodeB) which is responsible for the control plane transmission and data transmission and one connection with SeNB (secondary eNB, secondary evolved NodeB) which is responsible for the data transmission.

[0035] As the MMW links are easily to be blocked, it is possible to establish multiple connections with the MMW links for data transmission. In this way, when one MMW link is blocked, the data can be transmitted through another MMW link. But dual connectivity in 3GPP didn't support the multiple connections and there is no specification on how to support the multiple connections.

[0036] Secondly, in LTE specification for dual connectivity, when the SeNB change is needed, the MeNB will send the SeNB addition request to the target SeNB, and the target SeNB will feedback an acknowledge for the SeNB addition request. If the addition of target SeNB resources was successful, the MeNB initiates a command for a release of the source SeNB resources towards UE and Source SeNB.

[0037] In the MMW network, as the MMW links are easily to be blocked, the fast transmission point switch is needed more frequently. If the same solution is used in the multiple connectivity of the LTE link and MMW links, firstly, the procedure will suffer large latency of two round of X2 interface especially when the X2 interface is non-ideal. Secondly, not only the SeNB change takes large latency, but also an establishment for a new connection through a SeNB addition procedure will need take more latency in a link transmission recovery as a connection with a previous source eNB is released. Therefore, the previously defined procedures in LTE dual connectivity cannot be used in the MMW network, and a new fast handover and recovery solution are needed.

[0038] In addition, in current specification for dual connectivity in 3GPP, when the MeNB is changed, the MeNB should firstly send a handover request to the target MeNB, and the target MeNB will send back an acknowledgement for the handover request; if the handover request for the target eNB resources is successful, the MeNB will send a release request towards the source SeNB .The MeNB will also send the radio resource control (RRC) reconfiguration message to the UE to trigger the UE to apply a new configuration. Upon receiving the new configuration, the UE releases the entire SeNB configuration. Only when the handover is completed, then the SeNB connection can be added again through the SeNB addition procedure.

[0039] However, in the network with the coexistence of a LTE link and MMW links, due to the wider bandwidth and the large number of antennas, the MMW links can provide more capacity than the LTE link, therefore the data transmission is mainly up to the MMW lins. The current MeNB change mechanism need to release the transmission of SeNB, if the MMW eNB acts as SeNB, then the data transmission has to be stopped until the SeNB is added again when the MeNB handover is completed. Therefore the large interruption time will be introduced.

[0040] Therefore, the present disclosure provides a network system where the user has multiple connections with LTE link and MMW links as well as a mobility scheme thereof. According to embodiments of the present disclosure, the terminal device may establish multiple connections with one LTE network device and multiple MMW network devices. The multiple MMW network devices constitute a network device cluster. The terminal device will establish a connection respectively with MMW network devices in the cluster. At least one MMW network device in the cluster is selected as a serving MMW network device which is responsible for transmit/receive the data. The other MMW network devices in the cluster are used as backup links for fast data transmission handover to avoid disconnection of the MMW links due to blockage. Therefore, control plane transmission for the terminal device is at least executed through the LTE network device, and data plane transmission for the terminal device is executed through the at least one MMW network device in the network device cluster which is selected as the serving network device. [0041] An example embodiment of the present disclosure will be described in detail in conjunction with Fig. 1 to Fig. 3. Fig. 1 is a diagram illustrating a network system 100 according to an embodiment of the present disclosure. The network system 100 is only a portion of a communication network. The network system 100 includes two terminal devices 110₁ and 110₂, one LTE network device 120 and six MMW network devices

The terminal device 110i communicates with the LTE network device 120 and at least one MMW network device (MMW network device 130i in the present example) in a network device cluster formed by the MMW network devices 130^130₃. Similarly, the terminal device 110₁ communicates with the LTE network device 120 and at least one MMW network device (not shown) in a network device cluster formed by the MMW network devices 130₄-130₆. [0042] Here, the MMW network device for the current communication of the terminal device is hereinafter referred to as a serving network device or MMW serving network device. It is appreciated that the number of the LTE network device, the MMW network device and the terminal device shown here is only intended for illustration purpose not for limitation purpose. The network system 100 may include any proper number of LTE network devices, MMW network devices and terminal devices. It is feasible to form a network device cluster including any proper number of MMW network devices for the terminal device, and to select any proper number of MMW network devices in the network device cluster as the serving network devices for use in the data plane transmission for the terminal device.

[0043] The communication in the network system 100 may be implemented according to any proper communication protocol, including but not limited to cellular communication protocols such as the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G), a wireless local area network communication protocol such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and/or any other protocols currently known or to be developed in the future. Furthermore, the communication employs any proper wireless communication technology, including but not limited to Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Address (TDMA), Frequency Division Duplexing (FDD), Time Division Duplexing (TDD), Many-Input Many-Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), and/or any other technologies currently known or to be developed in the future.

[0044] In the following description, more detailed description will be presented mainly by taking the terminal device 110₁ as an example. However, it should be appreciated that the terminal device 110₂ and the like may communicate in a manner similar to the terminal device 110i.

[0045] Fig. 2 is a diagram illustrating a communication procedure 200 of the network system 100 according to an embodiment of the present disclosure. As shown in Fig. 2, the terminal device 110₁ and the LTE network device 120 establish a connection (as shown by 210). The terminal device 110i performs control plane transmission or both control plane transmission and data plane transmission via the connection (210) with the LTE network device 120. Then, the terminal device 110₁ establish a connection (e.g., as shown by 220-240) with each of the MMW network devices 130^130₃ in the corresponding network device cluster. The terminal device 110i performs data plane transmission via the connection (e.g., as shown by 220) with at least one MMW network device in the MMW network devices 130i-130₃.

[0046] Here, the terminal device 110₁ actually establishes connections (220-240) with the MMW network devices 130^130₃ in the corresponding network device cluster, but performs data plane transmission only via a part (220) of the connections in the network device cluster, and uses other connections as backup links. Therefore, once the current channel quality is found get worse, fast handover of data links may be implemented to ensure communication quality. As shown in Fig. 1, if the link of the current MMW network device, for example, the MMW network device 130i for terminal device 110i is blocked, the terminal device 110i may fastly switch the transmission/reception to other MMW network devices (for example, at least one of the MMW network devices 130₂-130₃) in the cluster.

[0047] On the other hand, as the terminal device (e.g., terminal device 1100 moves, a new network device cluster may be formed to support and ensure stable channel quality. Fig. 3 is a diagram illustrating a network system 100 with a movement of a terminal device according to an embodiment of the present disclosure. As shown in Fig. 3, the terminal device 110₁ moves from point A to point B in a coverage area of the LTE network device 120. Correspondingly, a new network device cluster having MMW network devices 130_1; 130₂, 130₄ is formed, and the connection with the MMW network device 130₃ is released.

[0048] The basic communication scheme of the novel network system according to the embodiment of the present disclosure has already been described in conjunction with Fig. 1 to Fig. 3. Based on this communication scheme, the embodiment of the present disclosure correspondingly provides communication methods implemented respectively at the terminal device, LTE network device and MMW network device. Several example implementations will be described in detail in conjunction with Fig. 4 to Fig. 6.

[0049] Fig. 4 is a flow chart of a communication method 400 implemented at a terminal device (e.g., the terminal device 110₁ in Fig. 1 to Fig. 3) according to an embodiment of the present disclosure. As shown in Fig. 4, at block 410, a first connection (as shown by 210 in Fig. 2) between the terminal device (e.g., the terminal device 1 lOi in Fig. 1 to Fig. 3) and a LTE network device (e.g., the LTE network device 120 in Fig. 1 to Fig. 3) is established at least for use in control plane transmission for the terminal device.

[0050] In an embodiment, the terminal device may send a random access procedure (RACH) to the LTE network device to establish a connection with the LTE network device. The random access procedure might be triggered by the user's response to downlink paging signal or by uplink data transmission. This is well known by those skilled in the art, and will not be detailed any more. The connection at least may be used for the control plane transmission of the terminal device, i.e., used for transmission of control information such as control signaling. In other cases, in addition to the control plane transmission, the connection may further be used for data plane transmission of the terminal device, namely, used for transmission of data information such as traffic data.

[0051] Then, at block 420, connections (as shown by 220-240 in Fig. 2) between the terminal device (e.g., the terminal device 1 lOi in Fig. 1 to Fig. 3) with MMW network devices (e.g., MMW network devices 130i-130₃ in Fig. 1 to Fig. 3) in the network device cluster are established. To this end, it might be necessary to determine the network device cluster for the terminal device.

[0052] In an embodiment, after the terminal device establishes the connection with the LTE network device at block 410, the terminal device may obtain information about MMW network devices from the LTE network device. The information about MMW network devices for example may include configuration information for measurements of MMW network devices. For example, the configuration information may include listing, measurement carrier, measurement period and the like of MMW network devices to be measured. In other embodiments, the information about MMW network devices may further include configuration information for report. This point is different from E-UTRAN (Evolved UMTS (Universal Mobile Telecommunication System) Terrestrial Radio Access Network) measurements for handover. Therefore, in E-UTRAN, neighboring network devices are detected depending on the terminal device, without indicating the neighboring network devices to the terminal device for use in searching and measuring a network device

[0053] In such example, at block 420, the terminal device may extract, from the information about the MMW network device, configuration information about the network device cluster, and determine the network device cluster according to the configuration information. It may be understood that in this case, the network device cluster may be pre-specified by the network device.

[0054] In an embodiment, the network device cluster may be pre-specified in association with the LTE network device. More specifically, one LTE network device may be associated with a plurality of MMW network devices, which means that one LTE network device may have a cluster of MMW network devices. When the terminal device has connection with the LTE network device, a corresponding MMW network device cluster will be determined.

[0055] In another embodiment, the network device cluster may be pre-specified in association with the MMW network device. More specifically, one MMW network device is associated with a plurality of MMW network devices, which means one MMW network device may have a cluster of associated MMW network devices. Once a MMW serving network device is determined (e.g., a MMW network device having a maximum reference signal reception power (RSRP)), the corresponding MMW network device cluster is determined. Specifically, the terminal device may, based on the configuration information obtained from the LTE network device, perform channel quality measurement on relevant MMW network devices to select a MMW network device with the optimal channel quality (e.g., MMW network device having the maximum RSRP value), thereby determining a MMW network device cluster associated with the selected MMW network device as the corresponding network device cluster. [0056] Alternatively or additionally, in another embodiment, the network device cluster may be pre- specified in association with a wave beam. More specifically, one wave beam may be associated with multiple wave beams of one or more MMW network devices, which means that each wave beam may have a cluster of associated MMW network devices. Once the wave beam is determined (e.g., a wave beam having a maximum reference signal reception power (RSRP)), the corresponding network device (wave beam) cluster of multiple wave beams of one or more MMW network devices is determined. Specifically, the terminal device may, based on the configuration information obtained from the LTE network device, perform corresponding wave beam measurement on relevant MMW network devices to select a wave beam with the optimal channel quality (e.g., wave beam having the maximum RSRP value), thereby determining a MMW network device cluster associated with the wave beam as the corresponding network device cluster.

[0057] Besides or in place of the network device cluster being pre- specified by the LTE network device, in some embodiments, the network device cluster may be determined by the terminal device. In this case, the terminal device may further obtain, from the LTE network device, configuration information about additional standards for formation of the network device cluster, for used by the terminal device to form the network device cluster. For example, additional standards may include the number, selection manner and the like of the network device clusters. For example, in an embodiment, the terminal device himself may select, from a plurality of candidate network devices (e.g., MMW network devices 130^130₆ in Fig. 1), several network devices to form the network device cluster. That is to say, the network device cluster is based on the user. This is described in detail in conjunction with the embodiment of Fig. 5. Fig. 5 is a flow chart of a procedure of determining a network device cluster implemented at a terminal device according to an embodiment of the present disclosure.

[0058] As shown in Fig. 5, at block 510, the terminal device obtains configuration information about a plurality of candidate network devices from a LTE network device. Specifically, the terminal device may obtain information about MMW network devices from the LTE network device. In an embodiment, the information about MMW network devices may include configuration information about measurement for MMW network devices. For example, the configuration information about measurement may include listing, measurement carrier, measurement period and the like of the MMW network devices to be measured. In other embodiments, the information about MMW network device may further include configuration information about report. This point is different from E-UTRAN measurement for handover. Therefore, in E-UTRAN, neighboring network devices are detected depending on the terminal device, without indicating the neighboring network devices to the terminal device for use in searching and measuring a network device. [0059] At block 520, channel quality measurement is performed for the plurality of candidate network devices based on the configuration information. Specifically, the terminal device may perform channel quality measurement on the plurality of candidate network devices based on the configuration information about the plurality of candidate network devices obtained from the LTE network device, e.g., the above configuration information about measurement. In an embodiment, for example, it is feasible to perform the channel quality measurement based on measurement of RSRP values of respective candidate MMW network devices. Certainly, it is also feasible to perform the channel quality measurement in a manner already known in the art or any other proper manners to be developed in the future.

[0060] At block 530, the network device cluster is determined from the plurality of candidate network devices based on a result of the channel quality measurement. In an embodiment, the terminal device may for example select network devices (or wave beams) having N maximum RSRP values or network devices (or wave beams) whose RSRP values are larger than a certain threshold to form the MMW network device cluster for the data plane transmission of the terminal device. [0061] In other embodiments, the terminal device may send the result of the channel quality measurement to the LTE network device, and receive information about a network device cluster from the LTE network device, the network device cluster being determined from the plurality of candidate network devices by the LTE network device based on the result of the channel quality measurement. The determination procedure is similar to the operation in steps 520 and 530 implemented on terminal device side, and will not be detailed any more here.

[0062] The determination of the network device cluster is described by way of example. After the network device cluster is determined, the terminal device establishes connections (as shown by 220-240 in Fig. 2) with respective MMW network devices in the network device cluster. For example, terminal device may implement connections with the respective MMW network devices in the determined network device cluster via the random access procedure. In one embodiment, at this time, the LTE network device requests a serving gateway for establishing data paths between it and respective MMW network devices in the network device cluster.

[0063] Returning to Fig. 4, at block 430, in response to the MMW network device (e.g., MMW network device 130i in Fig. 1 to Fig. 3) in the network device cluster being selected as a serving network device for the terminal device (e.g., terminal device 110i in Fig. 1 to Fig. 3), data plane transmission of the terminal device is performed via the second connection (as shown by 220 in Fig. 2) between the terminal device and the MMW network device.

[0064] Specifically, as previously mentioned, although at block 420 the terminal device establishes connections with all MMW network devices in the network device cluster, only one or more connections are selected therefrom for the data plane transmission of the terminal device, and the remaining connections serve as backup links. In this way, failure to link connection caused by the blocking of the MMW links may be overcome.

[0065] At block 430, the selection of the serving network device may be implemented based on channel quality measurement of network devices in the network device cluster. For example, it is feasible to select therefrom at least one network device with optimal channel as the serving network device. In an embodiment, the selection of the serving network device may be performed at a terminal device. This will be described in detail in conjunction with the embodiment of Fig. 6. Fig. 6 is a flow chart of a procedure of selecting a serving network device implemented at a terminal device according to an embodiment of the present disclosure. [0066] As shown in Fig. 6, at block 610, the terminal device obtains configuration information about a network device cluster from a LTE network device. In this case, the network device cluster is determined, and reference may be made to the above depictions of step 420 in conjunction with Fig. 4 for its determination procedure. For example, the terminal device may obtain configuration information about measurement for respective network devices in the network device cluster from the LTE network device.

[0067] At block 620, channel quality measurement is performed for the network device cluster based on the configuration information. Specifically, the channel quality measurement may be performed based on for example RSRP or other values. Then, at block 630, a MMW network device serving as the serving network device is determined from the network device cluster based on a result of the channel quality measurement. In an embodiment, the terminal device may select at least one network device with optimal channel in the determined network device cluster as the serving network device to send a request for service to the corresponding serving network device.

[0068] Returning to Fig. 4, in another embodiment, the selection of the serving network device at block 430 may be performed at a predetermined network device (a third network device). The predetermined network device is the LTE network device. In this case, in an embodiment, it is possible to perform the selection of the serving network device at the LTE network device. In this case, the terminal device may send the result of the channel quality measurement to the LTE network device, and receive information about the serving network device from the LTE network device. The serving network device for example is determined from the network device cluster by the LTE network device based on the channel quality measurement result.

[0069] Alternatively, in another embodiment, the selection of the serving network device may be performed at one or more MMW network devices in the network device cluster. In this case, the terminal device may send the result of the channel quality measurement to the MMW network devices and receive information about the serving network device from the MMW network devices. The serving network device for example is determined from the network device cluster by the MMW network devices based on the result of the channel quality measurement. In other embodiments, the terminal device may send the result of the channel quality measurement to the LTE network device which forwards the result to the MMW network devices, and receive information about a serving network device from the MMW network devices, the serving network device being determined from the network device cluster by the MMW network devices based on the result of the channel quality measurement.

[0070] In the communication method 400 implemented at a terminal device according to an embodiment of the present disclosure, to ensure the communication channel quality, the terminal device performs channel quality measurement and radio link monitoring. If the standard for a serving network device re-selection is satisfied, a serving network device re-selection procedure is triggered (e.g., the serving network device of the terminal device 110i in Fig. 1 changes from the MMW network device 103i to the MMW network device 130₂).

[0071] In an embodiment, the terminal device (e.g., terminal device 110₁ shown in Fig. 1) may re- select the serving network device based on the result of the channel quality measurement and send a request for service to the new serving network device (e.g., MMW network device 130₂ shown in Fig. 1) for data transmission and reception. The previous serving network device (e.g., MMW network device 130i shown in Fig. 1) may be informed of the change of the serving network device, or the previous serving network device itself may detect the change of the serving network device for example by not having received acknowledgement/non-acknowledgement (ACK/NACK) of data transmission and correspondingly stop data transmission and reception.

[0072] In another embodiment, it is feasible to perform re-selection of the serving network device at a LTE network device (e.g., LTE network device 120 shown in Fig. 1). In this case, terminal device may report the result of the channel quality measurement to the LTE network device, and receive from the LTE network device information about the newly- selected serving network device.

[0073] In another embodiment, it is feasible to perform re-selection of the serving network device at a network device (e.g., a certain network device in MMW network devices 130i-130₃ shown in Fig. 1) in the network device cluster. In this case, the MMW network device in the network device cluster may be called a centric node. In an embodiment, the terminal device may report the result of the channel quality measurement to the MMW network device, and then the MMW network device performs re-selection of the serving network device based on the result of the channel quality measurement and notifies the newly- selected MMW network device and terminal device and/or previous serving network device. In another embodiment, the terminal device may report the result of the channel quality measurement to the LTE network device, the LTE network device forwards the result of the channel quality measurement to the MMW network device, and the MMW network device performs re- selection of the serving network device based on the result of the channel quality measurement and notifies the newly- selected MMW network device and terminal device and/or previous serving network device.

[0074] Specific operations of re-selecting the serving network device are similar to the selection of the serving network device described above, and the details will not be presented any more here. Generally, in an embodiment, it is feasible to re-select the serving network device from the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[0075] Specifically, the channel quality measurement on the network device cluster may include at least one of: channel quality measurement on the serving network device in the network device cluster; or channel quality measurement on other network devices in the network device cluster other than the serving network device. For example, when the channel quality of the serving network device is lower than a predetermined threshold, the re- selection of the serving network device may be performed. Alternatively or additionally, when the channel qualities of one or more of other network devices in the network device cluster other than the serving network device are higher than a predetermined threshold, the re- selection of the serving network device may be performed. For example, when the channel quality of the serving network device is lower than the predetermined threshold and the channel qualities of one or more of other network devices are equal to or higher than a predetermined threshold, the re-selection of the serving network device may be performed. The predetermined threshold may be pre-determined for example according to experience.

[0076] Regarding the channel quality measurement of the LTE network device, for example, it is feasible to judge whether to perform the re- selection of the serving network device based on changes of channel quality of the LTE network device. Specifically, when the change of the channel quality of the LTE network device is larger than a first threshold and smaller than or equal to a second threshold (the second threshold is larger than the first threshold), the re-selection of the serving network device may be performed, and when the change of the channel quality of the LTE network device is smaller than the first threshold, the re- selection of the serving network device may not be performed. When the change of the channel quality of the LTE network device is larger than the second threshold, update of the network device cluster may be performed. Regarding information about movement of the terminal device, for example, it is feasible to judge whether to perform the re-selection of the serving network device based on the change of position information of the terminal device. For example, when the terminal device's position span is larger than or equal to the first threshold and smaller than or equal to the second threshold (the second threshold is smaller than the first threshold), the re-selection of the serving network device may be performed; when the terminal device's position span is smaller than the first threshold, re-selection of the serving network device may not be performed. When the terminal device's position span is larger than the second threshold, the update of the network device cluster may be performed, which will be described later.

[0077] Specific standards for judging whether to perform re-selection of the serving network device as listed above may be used individually or used in any combinations. Furthermore, the standards for judging whether to perform re-selection of the serving network device are not limited to the situations listed above, and may be implemented in any other suitable manners.

[0078] In the communication method 400 implemented at a terminal device according to an embodiment of the present disclosure, if a standard for network device cluster updating is satisfied, a procedure of updating a network device cluster is triggered (e.g., in Fig. 3, the network device cluster for the terminal device 110i is updated from the MMW network device 130i-130₃ to the MMW network devices 130i, 103₂, 130₄).

[0079] In an embodiment, regarding a MMW network device (e.g., MMW network device 130₃ shown in Fig. 3) not in the new network device cluster, in an embodiment, the terminal device (namely, the terminal device 1 lOi shown in Fig. 3) may directly send a connection release request to the MMW network device. In another embodiment, the terminal device may send a connection release request to the LTE network device and the LTE network device forwards the connection release request to the MMW network device. Meanwhile, a data path for the MMW network device will be released. Regarding a new MMW network device (e.g., MMW network device 130₄ shown in Fig. 3) added to the network device cluster, in an embodiment, the terminal device (e.g., terminal device 110₁ shown in Fig. 3) may establish a connection with the MMW network device and send to the LTE network device a request for performing data path establishment between the newly-added MMW network device and the serving gateway or a network device serving as the centric node.

[0080] In another embodiment, regarding a MMW network device not in the new network device cluster, the LTE network device sends a connection release command to the terminal device and the MMW network device. Meanwhile, a data path for the MMW network device will be released. Regarding a new MMW network device added to the network device cluster, the LTE network device sends to the terminal device a command for performing new connection establishment with the newly-added MMW network device in the network device cluster, and requests to perform data path establishment between the newly-added MMW network device and the serving gateway or a network device serving as the centric node.

[0081] In addition, if MMW network device in the old network device cluster is still in the new network device cluster, data transmission is not interrupted. This may be considered as a transmission mechanism with the user as a core. Since there are other MMW network devices for data transmission in the network device cluster, it is unnecessary to immediately establish a connection with the newly-added MMW network device. To avoid interruption of data transmission, connection establishment time may be coordinated between the MMW network devices (the newly- added MMW network device and the serving network device). In an embodiment, the terminal device may send a connection request to the newly-added MMW network device to establish a connection therewith when data is not transmitted through the serving network device.

[0082] In an embodiment, the network device cluster may be updated based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device; and the like.

[0083] Specifically, the channel quality measurement on the network device cluster may include at least one of: channel quality measurement on the serving network device in the network device cluster; or channel quality measurement on other network devices in the network device cluster other than the serving network device. For example, when the channel quality of the serving network device is lower than a predetermined threshold and the channel qualities of one or more of other network devices are also lower than the predetermined threshold, the re- selection of the network device cluster may be performed. The predetermined threshold may be pre-determined for example according to experience.

[0084] It is possible, based on the channel quality measurement on the LTE network device, for example determine the change of the channel quality of the LTE network device, and judge whether to perform update of the network device cluster according to the change. For example, when the change of the channel quality of the LTE network device exceeds a certain threshold, the update of the network device cluster may be performed. For example, when the terminal device switches from one LTE network device to another LTE network device, the update of the network device cluster may be performed.

[0085] It is possible, based on the information about movement of the terminal device, for example determine the change of the terminal device's position, and judge whether to perform update of the network device cluster according to the change. For example, when the terminal device's position span is larger than a predetermined threshold (e.g., the second threshold mentioned above), the update of the network device cluster may be performed. When the terminal device's position span is smaller than or equal to the predetermined threshold, the update of the network device cluster may not be performed. [0086] Specific standards for judging whether to perform the update of the network device cluster as listed above may be used individually or used in any combinations. Furthermore, the standards for judging whether to perform the network device cluster are not limited to the situations listed above, and may be implemented in any other suitable manners. [0087] In the communication method 400 implemented at terminal device according to an embodiment of the present disclosure, to fast switch service links between MMW network devices in the network device cluster, a desired data packet in a downlink may be obtained at all MMW network devices in the network device cluster. In other situations, the data may be always obtained at the MMW serving network device, and may be obtained at other MMW network devices in the network device cluster only when the quality of the MMW serving network device gets worse. In an embodiment, the terminal device may, in response to measuring that the channel quality of the serving network device gets worse, request a fourth network device to route the stored downlink data to network devices in the network device cluster. In the case that the downlink data is only stored in the LTE network device, the fourth network device is LTE network device. In this case, terminal device may, in response to measuring that the channel quality of the serving network device gets worse, request the LTE network device to route the stored downlink data to network devices in the network device cluster. In the case that the downlink data is only stored in a certain network device in the network device cluster, the fourth network device is a network device in the network device cluster. In this case, terminal device may, in response to measuring that the channel quality of the serving network device gets worse, request the network device to route the stored downlink data to other network devices in the network device cluster.

[0088] In the communication method 400 implemented at terminal device according to an embodiment of the present disclosure, since data is buffered in each MMW network device, it is necessary to perform data management to optimize the storage space. In an embodiment, the terminal device may send information about data reception state of the terminal device to MMW network devices in the network device cluster other than the MMW serving network device. Specifically, for example, the terminal device may send a status protocol data unit (PDU) to MMW network devices in the network device cluster other than the MMW serving network device, to indicate the data packet correctly received by the terminal device. In this way, the MMW network devices in the network device cluster may perform processing for the self-buffered downlink data based on the information about the data packet correctly received by the terminal device. For example, the data packet correctly received by the terminal device is deleted, and data packets not correctly received or not received by the terminal device are stored, and the like. In addition, data buffering and packet management requires sequential numbering between a central network device and the MMW network device (or the serving gateway and the MMW network device). [0089] Fig. 7 is a flow chart of a communication method 700 implemented at a first network device (LTE network device 120 in Fig. 1 to Fig. 3) according to an embodiment of the present disclosure. As shown in Fig. 7, at block 710, a first connection (as shown by 210 in Fig. 2) between the LTE network device (e.g., LTE network device 120 in Fig. 1) and a terminal device (e.g., terminal device 110₁ in Fig. 1) is established for at least use in control plane transmission of the terminal device.

[0090] At block 720, configuration information for a network device cluster is sent to the terminal device, so that the terminal device establishes connections (as shown by 220-240 in Fig. 2) with network devices (e.g., MMW network devices 130^130₃ in Fig. 1) in the network device cluster, and performs data plane transmission of the terminal device via the connection (as shown by 220 in Fig. 2) with the MMW network device (e.g., MMW network device 130i in Fig. 1) in the network device cluster selected as a serving network device.

[0091] In an embodiment, the network device cluster may be pre-specified in association with the LTE network device. In another embodiment, the network device cluster may be pre-specified in association with the MMW network device. In another embodiment, the network device cluster may be pre-specified in association with a wave beam.

[0092] In an embodiment, the method 700 may further comprise one or more optional steps not shown. For example, in some embodiments, configuration information about a plurality of candidate network devices is sent to the terminal device. Then, it is feasible to receive, from the terminal device, a result of the channel quality measurement performed by the terminal device for the plurality of candidate network devices. The network device cluster may be determined from the plurality of candidate network devices based on the result of the channel quality measurement.

[0093] In an embodiment, it is feasible to receive, from the terminal device, a result of the channel quality measurement performed by the terminal device for the network device cluster based on the configuration information. It is feasible to, based on the result of the channel quality measurement, send to the terminal device information about the MMW network device determined from the network device cluster as the serving network device, and notify the MMW network device that it is selected as the severing network device for the terminal device.

[0094] In an embodiment, it is feasible to receive, from the terminal device, a result of the channel quality measurement performed by the terminal device for the network device cluster based on the configuration information, and forward the result of the channel quality measurement to network devices in the network device cluster. In this case, the LTE network device may specify a certain network device in the network device cluster to which the result is forwarded, or the network pre-defines a certain network device in the network device cluster, so that the network device in the network device cluster performs the operation of determining the network device cluster.

[0095] In an embodiment, the serving network device may be re- selected from the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the first network device; or information about movement of the terminal device. Alternatively or additionally, in an embodiment, the network device cluster may be updated based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the first network device; or information about movement of the terminal device. Reference may be made to the above relevant portions in conjunction with method 400 for specific details, which will not be detailed any more here. [0096] In the communication method 700 implemented at the LTE network device according to an embodiment of the present disclosure, to fast switch service links between MMW network devices in the network device cluster, it is also expected that data in a downlink may be obtained at all of the MMW network devices in the network device cluster. In this case, in an embodiment, the method 700 further comprises: sending a data path establishment request to a serving gateway to establish data paths from the serving gateway to the network devices in the network device cluster. Specifically, when multiple connections with the MMW network devices in the network device cluster are established, data transmission paths from the serving gateway to respective MMW network devices are established. Furthermore, when the network device cluster is updated and the MMW network device is not in the network device cluster, the path will be released. Regarding the MMW network device newly added in the network device cluster, the path is also established. In an embodiment, respective MMW network devices respectively include corresponding buffers to store downlink data. As such, the downlink data may be stored in each network device in the network device cluster so as to fast switch the service links if necessary.

[0097] In some cases, to more optimize system performance, the downlink data may be stored only at one network device, and the network device routes the stored downlink data to the network devices in the network device cluster if necessary. In this case, the network device may be called a central network device (a fifth network device). In an embodiment, the LTE network device may request the serving gateway to establish a data path with the central network device. In some embodiments, the central network device may be the first network device. In this case, the method 700 may further comprise: storing the downlink data from the serving gateway via the data path; and in response to the determination of the network device cluster and a request from the terminal device, routing the downlink data to each network device in the network device cluster.

[0098] In the communication method 700 implemented at the LTE network device according to an embodiment of the present disclosure, if a standard for a serving network device re-selection is satisfied, a procedure of re-selecting a serving network device is triggered (e.g., the serving network device of the terminal device 110i in Fig. 1 changes from the MMW network device 130i to the MMW network device 130₂). In an embodiment, the serving network device may be re-selected from the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device. This point is similar to the above corresponding operation described in conjunction with Fig. 4 and will not be detailed again here. Specific operations of re-selecting the serving network device are similar to the above specific operations of selecting the serving network device described above, and the details will not be presented any more here.

[0099] In the communication method 700 implemented at the LTE network device according to an embodiment of the present disclosure, if a standard for a network device cluster update is satisfied, a procedure of updating a network device cluster is triggered (e.g., the network device cluster for the terminal device 110₁ in Fig. 3 updates from the MMW network devices 130i-130₃ to the MMW network devices 130i, 130₂, 130₄). In an embodiment, the network device cluster is updated based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device. This point is similar to the above corresponding operation described in conjunction with Fig. 4 and will not be detailed again here. Specific operations of updating the network device cluster are similar to the above specific operations of determining the network device cluster described above, and the details will not be presented any more here.

[00100] Fig. 8 is a flow chart of a communication method 800 implemented at an MMW network device (e.g., any network device in MMW network devices 130^130₆ in Fig. 1 to Fig. 3) according to an embodiment of the present disclosure. It may be appreciated that the MMW network device belongs to a network device cluster.

[00101] In an embodiment, the network device cluster may be pre-specified in association with a LTE network device. In another embodiment, the network device cluster may be pre-specified in association with a MMW network device. In another embodiment, the network device cluster may be pre-specified in association with a wave beam.

[00102] As shown in Fig. 8, at block 810, connections (as shown by 220-240 in Fig. 2) between the MMW network devices (e.g., MMW network devices 130^130₃ in Fig. 1) and the terminal device (e.g., terminal device 110₁ in Fig. 1) are established. At block 820, in response to the MMW network device (e.g., MMW network device 130i in Fig. 1) being selected as a serving network device for the terminal device, data plane transmission of the terminal device is performed via the connection (as shown by 220 in Fig. 2) established between the MMW network device and the terminal device.

[00103] In an embodiment, it is feasible to receive from the LTE network device a result of channel quality measurement performed by the terminal device for the network device cluster, and determine the serving network device for the terminal device from the network device cluster based on the result of the channel quality measurement.

[00104] In an embodiment, the serving network device may be re- selected from the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00105] In an embodiment, the downlink data may be received and stored. In some embodiments, the downlink data may be received from the serving gateway. Alternatively or additionally, the downlink data may be received from the LTE network device or other network devices in the network device cluster. [00106] In an embodiment, it is further possible to route the stored downlink data to other network devices in the network device cluster in response to a request from the terminal device, in the case that the MMW network device is selected as the serving network device for the terminal device.

[00107] In an embodiment, it is further possible to send, to other MMW network devices in the network device cluster, information about a data reception state of the terminal device in the case that the MMW network device is selected as the serving network device for the terminal device.

[00108] In an embodiment, it is further feasible to receive information about the data reception state of the terminal device, and process downlink data according to the received information. In this case, the MMW network device may receive the information about the data reception state of the terminal device from the terminal device or serving network device, for example, information about data packets correctly received by the terminal device. Based on the information about data packets correctly received by the terminal device, the MMW network device in the network device cluster may perform processing for the self -buffered downlink data. For example, the data packets correctly received by the terminal device is deleted, and data packets not correctly received or not received by the terminal device are stored, and the like. In addition, data buffering and packet management requires sequential numbering between a central network device and the MMW network device (or the serving gateway and the MMW network device).

[00109] The communication methods implemented respectively at a terminal device, a LTE network device and a MMW network device are described according to embodiments of the present disclosure in conjunction with Fig. 4 to Fig. 8. To facilitate understanding, a specific scenario is described in conjunction with Fig. 9. It should be appreciated that it is only intended for illustration purpose not for any limitation purpose.

[00110] Fig. 9 is a diagram illustrating an exemplary processing procedure 900 of a specific communication scenario according to an embodiment of the present disclosure. In this example, a processing procedure in the case of determining a MMW network device cluster at a LTE network device and selecting a serving network device at a terminal device is described. For example, in the example, the LTE network device may be implemented as the LTE network device 120 as shown in Fig. 1, the terminal device may be implemented as for example the terminal device 110i in Fig. 1, and the MMW network device may be implemented as for example the MMW network devices 130^130₃ in Fig. 1 to Fig. 3.

[00111] As shown in Fig. 9, the terminal device 110₁ establishes (902) a connection with the LTE network device 120. The LTE network device 120 sends to the terminal device 110i the configuration information about the MMW network device. The terminal device 110₁ sends (906) to the LTE network device 120 a result of channel quality measurement performed based on the configuration information. The LTE network device 120 determines the network device cluster based on the result. The LTE network device 120 respectively sends (908, 910, 912) a connection establishment request to respective MMW network devices 130^130₃ in the determined network device cluster. The MMW network devices 130^130₃ respectively send (914, 916, 918) an acknowledgement for the connection establishment to the LTE network device 120.

[00112] Then, the LTE network device 120 sends (920) the configuration information about the network device cluster to the terminal device 110₁. The terminal device 110₁ respectively establishes (922, 924, 926) connections with MMW network devices 130^130₃ via a random access. Furthermore, the terminal device 110i determines MMW network device 130i as the serving network device from the network device cluster, and sends (922) a request for service to the MMW network device 130i. At this time, the LTE network device 120 sends to an MME a request for performing a data path establishment procedure at 928. The MME sends (930) carrier information to the serving gateway (S-GW). The serving gateway respectively sends (932, 934, 936) the data packet to the MMW network devices 130i-130₃ for storage.

[00113] The terminal device 110₁ may transmit (938) data via the serving network device 130i. When the terminal device 110i re-selects the MMW network device 130₂ as the serving network device according to needs, terminal device 110i sends (940) a request for service to the MMW network device 130₂. Then, the terminal device 110₁ may transmit (942) data via the serving network device 130₂.

[00114] Corresponding to the communication methods 400, 700 and 800 described above, embodiments of the present disclosure may provide corresponding apparatus implemented at a terminal device, a LTE network device and a MMW network device, which will be described in detail in conjunction with Fig. 10 to Fig. 12.

[00115] Fig. 10 illustrates a block diagram of an apparatus 1000 implemented at a terminal device according to an embodiment of the present disclosure. It should be appreciated that the apparatus 1000 may be implemented for example at the terminal device 110i and terminal device 110₂ shown in Fig. 1. Alternatively, the apparatus 1000 may be the terminal device itself.

[00116] As shown in Fig. 10, the apparatus 1000 may comprise a first connection establishment unit 1010, a second connection establishment unit 1020 and a transmission unit 1030. The first connection establishment unit 1010 may be configured to establish a first connection between the terminal device and the LTE network device at least for use in control plane transmission of the terminal device. The second connection establishment unit 1020 may be configured to establish connections between the terminal device and network devices in the network device cluster. The transmission unit 1030 may be configured to, in response to the MMW network device in the network device cluster being selected as a serving network device for the terminal device, perform data plane transmission of the terminal device via a second connection between the terminal device and the MMW network device. [00117] In an embodiment, the apparatus 1000 may further comprise: a first obtaining unit configured to obtain configuration information about the network device cluster from the LTE network device. In some embodiments, the network device cluster may be pre-specified in association with the LTE network device. In another embodiment, the network device cluster may be pre-specified in association with the MMW network device. In another embodiment, the network device cluster may be pre-specified in association with a wave beam.

[00118] In an embodiment, the apparatus 1000 may further comprise: a second obtaining unit configured to obtain, from the LTE network device, configuration information about a plurality of candidate network devices; a first measurement unit configured to perform channel quality measurement on the plurality of candidate network devices based on the configuration information; and a network device cluster determining unit configured to determine the network device cluster from the plurality of candidate network devices based on the result of channel quality measurement.

[00119] In an embodiment, the network device cluster determining unit may further comprise: a first sending sub-unit configured to send the result of the channel quality measurement to the LTE network device; and a first receiving sub-unit configured to receive information about the network device cluster from the LTE network device, the network device cluster being determined from the plurality of candidate network devices by the LTE network device based on the result of the channel quality measurement.

[00120] In an embodiment, apparatus 1000 may further comprise: a third obtaining unit configured to obtain configuration information about the network device cluster from the LTE network device; a second measuring unit configured to perform channel quality measurement on the network device cluster based on the configuration information; a serving network device determining unit configured to, based on the result of the channel quality measurement, determine a MMW network device as the serving network device from the network device cluster.

[00121] In an embodiment, the serving network device determining unit may further comprise: a second sending sub-unit configured to send the result of channel quality measurement to the third network device; and a second receiving sub-unit configured to receive information about the serving network device from the third network device, the second network device being determined by the third network device from the network device cluster based on the result of the channel quality measurement.

[00122] In an embodiment, the second sending sub-unit may further comprise: a forwarding sub-unit configured to send the result of the channel quality measurement to the LTE network device to trigger the LTE network device to forward the result of the channel quality measurement to the third network device.

[00123] In an embodiment, the third network device may be an LTE network device. In another embodiment, the third network device may be a network device in the network device cluster.

[00124] In an embodiment, the apparatus 1000 may further comprise: a serving network device re-selection unit configured to re-select the serving network device based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00125] In an embodiment, the apparatus 1000 may further comprise: a network device cluster updating unit configured to update the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00126] In an embodiment, the apparatus 1000 may further comprise: a route requesting unit configured to, in response to measuring that the channel quality of the serving network device gets worse, request the fourth network device to route the stored downlink data to each network device in the network device cluster. In an embodiment, the fourth network device is the LTE network device. In another embodiment, the fourth network device is a network device in the network device cluster.

[00127] In an embodiment, the apparatus 1000 may further comprise: a state sending unit configured to send information about a data reception state of the terminal device to network devices in the network device cluster other than the serving network device.

[00128] Fig. 11 illustrates a block diagram of an apparatus 1100 implemented at a LTE network device according to an embodiment of the present disclosure. It should be appreciated that the apparatus 1100 may be implemented for example at the LTE network device 120 shown in Fig. 1 to Fig. 3. Alternatively, the apparatus 1100 may be the LTE network device itself.

[00129] As shown in Fig. 11, the apparatus 1100 may comprise a connection establishment unit 1110 configured to establish a first connection between the LTE network device and the terminal device at least for use in control plane transmission of the terminal device; and a first transmission unit 1120 configured to send to the terminal device configuration information for the network device cluster so that the terminal device establishes connections with network devices in the network device cluster based on the configuration information and performs data plane transmission of the terminal device by using the second connection with the MMW network device in the network device cluster selected as the serving network device.

[00130] In some embodiments, the network device cluster may be pre-specified in association with the LTE network device. In another embodiment, the network device cluster may be pre-specified in association with the MMW network device. In another embodiment, the network device cluster may be pre-specified in association with a wave beam. [00131] In an embodiment, the apparatus 1100 may further comprise: a second sending unit configured to send, to the terminal device, configuration information about a plurality of candidate network devices; a first receiving unit configured to receive, from the terminal device, the result of channel quality measurement performed by the terminal device for the plurality of candidate network devices based on the configuration information; and a network device cluster determining unit configured to determine the network device cluster from the plurality of candidate network devices based on the result of the channel quality measurement.

[00132] In an embodiment, the apparatus 1100 may further comprise: a second receiving unit configured to receive, from the terminal device, the result of channel quality measurement performed by the terminal device for the network device cluster based on the configuration information; a serving network device determining unit configured to determine a MMW network device as the serving network device from the network device cluster based on the result of the channel quality measurement; and a notifying unit configured to send to the terminal device information about the serving network device and notify the MMW network device that it is selected as the serving network device of the terminal device.

[00133] In an embodiment, the apparatus 1100 may further comprise: a forwarding unit configured to forward the result of the channel quality measurement to the network device in the network device cluster.

[00134] In an embodiment, the apparatus 1100 may further comprise: a serving network device re-selection unit configured to re-select the serving network device based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00135] In an embodiment, the apparatus 1100 may further comprise: a network device cluster updating unit configured to update the network device cluster based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00136] In an embodiment, the apparatus 1100 may further comprise: a third sending unit configured to send a data path establishment request to the serving gateway to establish a data path from the serving gateway to the network devices in the network device cluster. In an embodiment, the third sending unit may further include: a requesting sub-unit configured to request the serving gateway to establish a data path of the serving gateway and the fifth network device. In some embodiments, the fifth network device may be an LTE network device. In some embodiments, the fifth network device may be a network device in the network device cluster.

[00137] In an embodiment, the apparatus 1100 may further comprise: a storing unit configured to store the downlink data from the serving gateway via the data path; and a routing unit configured to, in response to the determination of the network device cluster and a request from the terminal device, route the downlink data to each network device in the network device cluster.

[00138] Fig. 12 illustrates a block diagram of an apparatus 1200 implemented at a MMW network device according to an embodiment of the present disclosure. The apparatus 1200 may be implemented on the MMW network device, for example, WWM network devices 130^130₃ shown in Fig. 1 to Fig. 3. Alternatively, the apparatus 1200 may be the MMW network device itself. It should be appreciated that the MMW network device belongs to one network device cluster.

[00139] As shown in Fig. 12, the apparatus 1200 may include: a connection establishment unit 1210 configured to connections between the MMW network devices and the terminal device; a transmitting unit 1220 configured to, in response to the MMW network device being selected as a serving network device for the terminal device, perform data plane transmission of the terminal device via the connection established between the MMW network device and the terminal device.

[00140] In an embodiment, the apparatus 1200 may further comprise: a first receiving unit configured to receive from the LTE network device a result of channel quality measurement performed by the terminal device for the network device cluster; and a serving network device determining unit configured to determine the serving network device for the terminal device from the network device cluster based on the result of the channel quality measurement.

[00141] In an embodiment, the network device cluster may be pre-specified in association with the LTE network device. In another embodiment, the network device cluster may be pre-specified in association with the MMW network device. In another embodiment, the network device cluster may be pre-specified in association with a wave beam.

[00142] In an embodiment, the apparatus 1200 may further comprise: a serving network device re-selection unit configured to re-select the serving network device based on at least one of: channel quality measurement on the network device cluster; channel quality measurement on the LTE network device; or information about movement of the terminal device.

[00143] In an embodiment, the apparatus 1200 may further comprise: a second receiving unit configured to receive the downlink data; and a storing unit configured to store the downlink data.

[00144] In an embodiment, the apparatus 1200 may further comprise: a routing unit configured to route the stored downlink data to other network devices in the network device cluster in response to a request from the terminal device, in the case that the second network device is selected as the serving network device for the terminal device.

[00145] In an embodiment, the apparatus 1200 may further include: a third receiving unit configured to receive information about a data reception state of the terminal device; and a data processing unit configured to process the downlink data according to the received information.

[00146] It should be appreciated that each element recited in the apparatus 1000, apparatus 1100 and apparatus 1200 corresponds to each step of the method 400, method 700 and method 800 described with reference to Fig. 4, Fig. 7 and Fig. 8. Furthermore, apparatus 1000, apparatus 1100 and apparatus 1200 and operations and features of elements included therein all correspond to operations and features described above in conjunction with Fig. 4 to Fig. 8, and have the same effects. Details will not be described any more here.

[00147] Units included in the apparatus 1000, apparatus 1100 and apparatus 1200 may be implemented in various manners, including software, hardware, firmware and any combination thereof. In an embodiment, one or more units may be implemented using software and/or firmware, e.g., machine executable instructions stored in a storage medium. In addition to the machine-executable instructions or alternatively, all or partial units in the apparatus 1000, apparatus 1100 and apparatus 1200 may be at least partially implemented by one or more hardware logic components. Exemplarily and unrestrictively, hardware logic components in an exemplary type that may be used comprise a field-programmable gate arrays (FPGA), Application Specific Integrated Circuit (ASIC), Application Specific Standard Parts (ASSP), System on Chip (SOC), Complex Programmable Logic Device (CPLD) and the like.

[00148] These units shown in Fig. 10 to Fig. 12 may be partially or totally implemented as hardware modules, software modules, firmware modules and any combinations thereof. Especially, in some embodiments, the flows, methods or processes described above may be implemented by hardware in a terminal device or a network device. For example, the network device or terminal device may employ use their transmitter, receiver, transceiver and/or processor or controller to implement methods 400, 700 and 800. [00149] Fig. 13 illustrates a block diagram of an apparatus 1300 adapted to implement an embodiment of the present disclosure. The apparatus 1300 may be used to implement a network device, for example, the LTE network device 120 or the MMW network device 130^130₃ shown in Fig. 1 to Fig. 3; the apparatus 1300 may be used to implement a terminal device, for example, the terminal device 110i and the terminal device 110₂ shown in Fig. 1 to Fig. 3.

[00150] As shown in the figure, the apparatus 1300 comprises a processor 1310 and a memory 1320 coupled to the processor 1310. The memory 1320 stores an instruction 1330 that may be run by the processor 1310. The memory 1320 may be in any suitable type adapted for local technical environment, and may be implemented using any suitable data storage technology, includes but not limited to a storage device based on a semiconductor, a magnetic storage device and system, and an optical storage device and system. Although Fig. 13 only shows a memory unit, the apparatus 1300 may include a plurality of physically different memory units.

[00151] The processor 1310 may be in any suitable type adapted for local technical environment, and may include but not limited to one or more of a general-purse computer, a dedicated computer, a microcomputer, a digital signal processor (DSP) and a process-based multi-core processor architecture. The apparatus 1300 may also include a plurality of processors 1310. The processor 1310 is configured to execute the methods 400, 700 and 800 to be implemented as shown in Fig. 4, Fig. 7 and Fig. 8.

[00152] It should be appreciated that the apparatus 1300 might further comprise any other desired means/elements, such as transmitter, receiver, transceiver and antenna, to execute corresponding actions, which are not shown in the figure for clarity purpose.

[00153] Generally, various exemplary embodiments of the present disclosure may be implemented in hardware or application-specific circuit, software, logic, or in any combination thereof. Some aspects may be implemented in hardware, while the other aspects may be implemented in firmware or software executed by a controller, a microprocessor or other computing device. When various aspects of the present invention are illustrated or described into block diagrams, flowcharts, or other graphical representations, it would be appreciated that the block diagrams, apparatus, system, technique or method described here may be implemented, as non-restrictive examples, in hardware, software, firmware, dedicated circuit or logic, common software or controller or other computing device, or some combinations thereof.

[00154] As an example, the implementations of the subject matter disclosed herein can be described in a context of machine-executable instructions which are included, for instance, in the program module executed in the device on a target real or virtual processer. Generally, a program module includes routine, program, bank, object, class, component and data structure, etc. and performs a particular task or implements a particular abstract data structure. In the implementations, the functions of the program modules can be combined or divided among the described program modules. The machine executable instructions for the program module can be executed in a local or distributed device. In the distributed device, the program module can be located in both the local storage medium and the remote storage medium.

[00155] The computer program code for implementing the method of the present disclosure may be complied with one or more programming languages. These computer program codes may be provided to a general-purpose computer, a dedicated computer or a processor of other programmable data processing apparatus, such that when the program codes are executed by the computer or other programmable data processing apparatus, the functions/operations prescribed in the flowchart and/or block diagram are caused to be implemented. The program code may be executed completely on a computer, partially on a computer, partially on a computer as an independent software packet and partially on a remote computer, or completely on a remote computer or server.

[00156] In the context of the present disclosure, the machine-readable medium may be any tangible medium including or storing a program for or about an instruction executing system, apparatus or device. The machine-readable medium may be a machine-readable signal medium or machine-readable storage medium. The machine-readable medium may include, but not limited to, electronic, magnetic, optical, electro-magnetic, infrared, or semiconductor system, apparatus or device, or any appropriate combination thereof. More detailed examples of the machine-readable storage medium includes, an electrical connection having one or more wires, a portable computer magnetic disk, hard drive, random-access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical storage device, magnetic storage device, or any appropriate combination thereof.

[00157] Besides, although the operations are depicted in a particular sequence, it should not be understood that such operations are completed in a particular sequence as shown or in a successive sequence, or all shown operations are executed so as to achieve a desired result. In some cases, multi-task or parallel-processing would be advantageous. Likewise, although the above discussion includes some specific implementation details, they should not be explained as limiting the scope of any invention or claims, but should be explained as a description for a particular implementation of a particular invention. In the present invention, some features described in the context of separate implementations may also be integrated into a single implementation. On the contrary, various features described in the context of a single implementation may also be separately implemented in a plurality of implementations or in any suitable sub-group.

[00158] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter specified in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

I/We Claim:

1. A communication method implemented at a terminal device, comprising:

establishing a first connection between the terminal device and a first network device at least for use in control plane transmission for the terminal device;

establishing connections between the terminal device and network devices in a network device cluster; and

in response to a second network device in the network device cluster being selected as a serving network device for the terminal device, performing data plane transmission for the terminal device via a second connection between the terminal device and the second network device.

2. The method according to Claim 1, further comprising:

obtaining, from the first network device, configuration information about the network device cluster, the network device cluster being pre-specified in association with the first network device.

3. The method according to Claim 1, further comprising:

obtaining, from the first network device, configuration information about the network device cluster, the network device cluster being pre-specified in association with the second network device.

4. The method according to Claim 3, further comprising:

obtaining, from the first network device, configuration information about a plurality of candidate network devices;

performing channel quality measurement on the plurality of candidate network devices based on the configuration information;

determining, from the plurality of candidate network devices, the second network device in the network device cluster, based on a result of the channel quality measurement; and

determining the network device cluster corresponding to the second network device based on the configuration information about the network device cluster.

5. The method according to Claim 1, further comprising: obtaining, from the first network device, configuration information about the network device cluster, the network device cluster being pre-specified in association with a wave beam.

6. The method according to Claim 5, further comprising:

7. The method according to Claim 1, further comprising:

performing channel quality measurement on the plurality of candidate network devices based on the configuration information; and

determining the network device cluster from the plurality of candidate network devices based on a result of the channel quality measurement.

8. The method according to Claim 7, wherein determining the network device cluster comprises:

sending the result of the channel quality measurement to the first network device; and receiving from the first network device information about the network device cluster, the network device cluster being determined by the first network device from the plurality of candidate network devices based on the result of the channel quality measurement.

9. The method according to Claim 1, further comprising:

obtaining, from the first network device, configuration information about the network device cluster;

performing channel quality measurement on the network device cluster based on the configuration information;

determining, from the network device cluster, the second network device as a serving network device, based on a result of the channel quality measurement.

10. The method according to Claim 9, wherein determining the second network device comprises:

causing the result of the channel quality measurement to be sent to a third network device; and

receiving, from the third network device, information about the second network device, the second network device being determined by the third network device from the network device cluster based on the result of the channel quality measurement.

11. The method according to Claim 10, wherein the third network device is the first network device.

12. The method according to Claim 10, wherein the third network device is a network device in the network device cluster.

13. The method according to Claim 12, wherein causing the result of the channel quality measurement to be sent to the third network device comprises:

sending the result of the channel quality measurement to the first network device to trigger the first network device to forward the result of the channel quality measurement to the third network device.

14. The method according to Claim 1, further comprising:

re- selecting the serving network device based on at least one of:

channel quality measurement on the network device cluster;

channel quality measurement on the first network device; or

information about movement of the terminal device.

15. The method according to Claim 1, further comprising:

updating the network device cluster based on at least one of:

channel quality measurement on the network device cluster;

channel quality measurement on the first network device; or information about movement of the terminal device.

16. The method according to Claim 15, further comprising:

releasing a connection between the terminal device and a network device to be removed from the network device cluster; and

establishing a connection between the terminal device and a network device to be added to the network device cluster.

17. The method according to Claim 1, further comprising:

in response to measuring that channel quality of the second network device gets worse, requesting a fourth network device to route stored downlink data to each network device in the network device cluster.

18. The method according to Claim 17, wherein the fourth network device is the first network device.

19. The method according to Claim 17, wherein the fourth network device is a network device in the network device cluster.

20. The method according to Claim 1, further comprising:

sending information about a data reception state of the terminal device to network devices in the network device cluster other than the second network device.

21. The method according to Claim 1, wherein the first network device is a network device based on long-term evolution (LTE) transmission, and each of the network devices in the network device cluster is a network device based on mm- wave (MMW) transmission.

22. A communication method implemented at a first network device, comprising: establishing a first connection between the first network device and a terminal device at least for use in control plane transmission for the terminal device; and

sending, to the terminal device, configuration information about a network device cluster so that the terminal device establishes connections with network devices in the network device cluster based on the configuration information and performs data plane transmission for the terminal device by using a second connection with a second network device in the network device cluster selected as a serving network device.

23. The method according to Claim 22, wherein the network device cluster is pre- specified in association with the first network device.

24. The method according to Claim 22, wherein the network device cluster is pre-specified in association with the second network device.

25. The method according to Claim 24, further comprising:

sending, to the terminal device, configuration information about a plurality of candidate network devices;

receiving, from the terminal device, a result of channel quality measurement performed by the terminal device for the plurality of candidate network devices based on the configuration information;

determining, from the plurality of candidate network devices, the second network device in the network device cluster, based on the result of the channel quality measurement; and

26. The method according to Claim 22, wherein the network device cluster is pre-specified in association with a wave beam.

27. The method according to Claim 26, further comprising:

receiving, from the terminal device, a result of channel quality measurement performed by the terminal device for wave beams of the plurality of candidate network devices based on the configuration information;

28. The method according to Claim 22, further comprising:

receiving, from the terminal device, a result of channel quality measurement performed by the terminal device for the plurality of candidate network devices based on the configuration information; and

determining the network device cluster from the plurality of candidate network devices based on the result of the channel quality measurement.

29. The method according to Claim 22, further comprising:

receiving, from the terminal device, a result of channel quality measurement performed by the terminal device for the network device cluster based on the configuration information;

determining, from the network device cluster, the second network device as the serving network device, based on the result of the channel quality measurement;

sending information about the second network device to the terminal device; and notifying the second network device that it is selected as the serving network device of the terminal device.

30. The method according to Claim 22, further comprising:

receiving, from the terminal device, a result of channel quality measurement performed by the terminal device for the network device cluster based on the configuration information; and

forwarding the result of the channel quality measurement to the network devices in the network device cluster.

31. The method according to Claim 22, further comprising:

re- selecting the serving network device based on at least one of:

channel quality measurement on the network device cluster;

channel quality measurement on the first network device; or

information about movement of the terminal device.

32. The method according to Claim 22, further comprising: updating the network device cluster based on at least one of:

channel quality measurement on the network device cluster;

channel quality measurement on the first network device; or

information about movement of the terminal device.

33. The method according to Claim 22, further comprising:

sending a data path establishment request to a serving gateway to establish data paths from the serving gateway to the network devices in the network device cluster.

34. The method according to Claim 33, wherein sending the data path establishment request further comprises:

requesting the serving gateway to establish a data path between the serving gateway and a fifth network device.

35. The method according to Claim 34, wherein the fifth network device is the first network device.

36. The method according to Claim 35, further comprising:

storing downlink data from the serving gateway via the data path; and

in response to the determination of the network device cluster or a request from the terminal device, routing the downlink data to the network devices in the network device cluster.

37. The method according to Claim 34, wherein the fifth network device is a network device in the network device cluster.

38. The method according to Claim 22, wherein the first network device is a network device based on long-term evolution (LTE) transmission, and each of the network devices in the network device cluster is a network device based on mm- wave (MMW) transmission.

39. A communication method implemented at a second network device, the second network device belonging to a network device cluster, the method comprising:

establishing a connection between the second network device and a terminal device; and in response to the second network device being selected as a serving network device for the terminal device, performing data plane transmission for the terminal device via the connection established between the second network device and the terminal device.

40. The method according to Claim 39, wherein the network device cluster is pre-specified in association with the second network device.

41. The method according to Claim 39, further comprising:

receiving, from a first network device, a result of channel quality measurement performed by the terminal device for a plurality of candidate network devices; and

determining, from the plurality of candidate network devices, the serving network device for the terminal device, based on the result of the channel quality measurement.

42. The method according to Claim 39, wherein the network device cluster is pre-specified in association with a wave beam.

43. The method according to Claim 42, further comprising:

receiving, from a first network device, a result of channel quality measurement performed by the terminal device for wave beams of the plurality of candidate network devices; and

44. The method according to Claim 39, further comprising:

receiving, from a first network device, a result of channel quality measurement performed by the terminal device for the network device cluster; and

determining, from the network device cluster, the serving network device for the terminal device, based on the result of the channel quality measurement.

45. The method according to Claim 44, wherein the network device cluster is pre-specified in association with the first network device.

46. The method according to Claim 39, further comprising:

re- selecting the serving network device based on at least one of: channel quality measurement on the network device cluster;

channel quality measurement on the first network device; or

information about movement of the terminal device.

47. The method according to Claim 39, further comprising:

receiving downlink data; and

storing the downlink data.

48. The method according to Claim 47, wherein receiving the downlink data comprises:

receiving the downlink data from a serving gateway.

49. The method according to Claim 47, wherein receiving the downlink data comprises:

receiving the downlink data from other network devices in the network device cluster or the first network device.

50. The method according to Claim 47, further comprising:

routing the stored downlink data to the other network devices in the network device cluster in response to a request from the terminal device, in the case that the second network device is selected as the serving network device for the terminal device.

51. The method according to Claim 47, further comprising:

receiving information about a data reception state of the terminal device; and processing the downlink data according to the received information.

52. The method according to Claim 39, wherein the first network device is a network device based on long-term evolution (LTE) transmission, and each of the network devices in the network device cluster is a network device based on mm- wave (MMW) transmission.

53. A terminal device, comprising:

a processor, and

a memory, the memory storing an instruction, the instruction, when executed by the processor, causing the terminal device to perform the method according to any of claims 1-21.

54. A network device, comprising:

a processor, and

a memory, the memory storing an instruction, the instruction, when executed by the processor, causing the network device to perform the method according to any of claims 22-38.

55. A network device, comprising:

a processor, and

a memory, the memory storing an instruction, the instruction, when executed by the processor, causing the network device to perform the method according to any of claims 39-52.