WO2013098984A1

WO2013098984A1 - Base station, wireless terminal, wireless communication system, and wireless communication method

Info

Publication number: WO2013098984A1
Application number: PCT/JP2011/080369
Authority: WO
Inventors: 義博河▲崎▼; 好明太田
Original assignee: 富士通株式会社
Priority date: 2011-12-28
Filing date: 2011-12-28
Publication date: 2013-07-04
Also published as: JPWO2013098984A1; JP5754516B2

Abstract

The purpose of the invention is to enable discrimination of process numbers used in retransmission control of different data signals. A sending unit (1a) is able to transmit a data signal to a wireless terminal (2) by means of a plurality of carriers (CC). When the sending unit (1a) transmits different data signals (5a, 5b), which are to be sent to the wireless terminal (2), in a single carrier (CC#1), a control unit (1b) adds, to an area that stores carrier recognition numbers for control signals (4a, 4b) that correspond to the different data signals (5a, 5b), identification information for identifying a process number used for retransmission control of each of the different data signals (5a, 5b).

Description

Base station, wireless terminal, wireless communication system, and wireless communication method

This case relates to a base station, a wireless terminal, a wireless communication system, and a wireless communication method that perform wireless communication.

In LTE-A (Long Term Evolution-Advanced), the specifications are being defined by 3GPP (3rd Generation Partnership Project), multiple CCs (Components) are used in each UL (Up Link) and DL (Down Link) radio links. Carrier) can be assigned to the wireless terminal. When a base station transmits a plurality of large-sized data having the same delay requirement characteristics to a wireless terminal in a short time, in addition to simultaneously transmitting using a plurality of CCs, a different transmission method is different for each CC. A plurality of data with different delay requirement characteristics can be transmitted simultaneously using different CCs by applying a modulation scheme / coding rate and different transmission power.

For example, in a certain CC, data such as voice data, which is small in size but has high delay requirement characteristics, is transmitted by the transmission diversity method. In another CC, data having a large size but having a slow delay requirement characteristic, such as data from an FTP (File Transfer Protocol) server, is transmitted by a MIMO (Multiple Input Input Multiple Output) spatial multiplexing method.

The number of CCs allocated to wireless communication can be set for each wireless terminal in the same base station cell, and even the same wireless terminal can be changed according to the amount of data traffic and the cell load It is. The base station performs data transmission using all or part of the CC allocated to the wireless terminal.

In addition, the base station transmits a data signal for transmitting data and a control signal for transmitting a radio parameter (modulation method, position on the frequency axis of the data signal, etc.) applied to the data signal on different carriers. It is also possible. This is called cross carrier scheduling.

When performing cross-carrier scheduling, the wireless terminal may monitor a control signal on a specific small number of CCs in order to receive the control signal regardless of the number of assigned CCs. For example, it is assumed that the base station allocates two CCs CC # 1 and CC # 2 to the radio terminal. Assume that the base station transmits data signal # 1 and its control signal # 1 using CC # 1. Further, it is assumed that the base station transmits data signal # 2 using CC # 2 and transmits control signal # 2 of data signal # 2 using CC # 1. In this case, the radio terminal only needs to monitor the control signals # 1 and # 2 with one CC # 1, and the data signals # 1 and # 2 based on the control signals # 1 and # 2 monitored with CC # 1. Can be received.

The control signal has an area called CIF (Carrier Indicator Field). In this area, the CC carrier identification number is stored. The wireless terminal can recognize on which CC the data signal corresponding to the control signal is transmitted by the carrier identification number stored in the CIF of the control signal.

For example, it is assumed that the wireless terminal monitors CC # 1 and receives control signals # 1 and # 2. When “# 1” indicating CC # 1 is stored in the CIF of the received control signal # 1, the wireless terminal transmits the data signal # 1 corresponding to the control signal # 1 on CC # 1. Can be recognized. The wireless terminal can receive the data signal # 1 transmitted by CC # 1. Similarly, when “# 2” indicating CC # 2 is stored in the CIF of the received control signal # 2, the wireless terminal transmits the data signal # 2 corresponding to the control signal # 2 using CC # 2. Can be recognized. And a radio | wireless terminal can receive data signal # 2 transmitted by CC # 2.

Conventionally, when communication is performed in a wide frequency band by using a plurality of continuous and / or discontinuous frequency bands (carrier elements) in combination, data (information) in which transmission power in the mobile station apparatus is kept low. ) Has been proposed (see, for example, Patent Document 1).

JP 2011-030118 A

By the way, in the LTE-A specification, in order to simultaneously transmit different data signals with different modulation schemes and coding rates without performing spatial multiplexing transmission, data signals are simultaneously transmitted on the same radio subframe of different CCs. For example, a data signal # 1 having a low QoS (Quality of Service) is transmitted by CC # 1, and a data signal # 2 having a high QoS is transmitted by CC # 2. Different modulation schemes and coding rates are applied to CC # 1 and CC # 2. Furthermore, you may transmit by applying different transmission power density (dBm / Hz) with respect to data signal # 1 and data signal # 2.

 HARQ (Hybrid Automatic 適用 Repeat Request) is applied to data transmitted individually to wireless terminals. The number of HARQ processes in 3GPP LTE is 8, and there is an independent HARQ entity for each CC. The control signal accompanying the data transmission includes HARQ process number ({1, 2, 3, 4, 5, 6, 7, 8}) information. For example, the control signal # 1 of the data signal # 1 includes the HARQ process number of the data signal # 1, and the control signal # 2 of the data signal # 2 includes the HARQ process number of the data signal # 2. It is. In the LTE-A specification, since HARQ is independent for each CC, when the data signal # 1 and the data signal # 2 are transmitted simultaneously on different CC # 1 and CC # 2, the HARQ process number is the data signal # 1 and the data signal # 2, the data signal # 1 and the data signal # 2 can be distinguished on the receiving side.

On the other hand, due to future specification changes, it is also conceivable to transmit a plurality of different data signals to a wireless terminal using one CC without using spatial multiplexing transmission. For example, the above-described data signal # 1 having a low QoS and data signal # 2 having a high QoS may be transmitted by the same CC # 1. Then, within one CC # 1, the data signals # 1 and # 2 are transmitted in different frequency regions, and the modulation method and the coding rate are made different between the data signal # 1 and the data signal # 2. It is possible.

However, when a plurality of different independent data signals are transmitted in one CC, there is a possibility that the HARQ process number matches between the data signals, and it becomes impossible to distinguish between the data signals. There was a problem.

For example, in the LTE DL, asynchronous HARQ is adopted, and when a certain data signal is retransmitted, the retransmission is performed (8 + n) ms after the previous transmission (in the LTE UL, a certain data signal is retransmitted). If this is the case, retransmission is performed 8 ms after the previous transmission). The value of n is variable and may be different for each retransmission. When transmitting a plurality of different data signals on the same CC, if the retransmission timing differs between the data, there is a situation in which a plurality of data having the same HARQ process number for the same wireless terminal exists in a certain radio subframe. Can occur. In such a situation, the wireless terminal cannot distinguish between a plurality of data signals having the same HARQ process number.

The present invention has been made in view of the above points, and an object thereof is to provide a base station, a wireless terminal, a wireless communication system, and a wireless communication method capable of distinguishing process numbers used in retransmission control of different data signals. And

In order to solve the above problems, a base station that performs wireless communication with a wireless terminal is provided. The base station transmits a data signal to the radio terminal using a plurality of carriers and a different data signal transmitted from the transmitter to the radio terminal in one carrier. A control unit including identification information for identifying each retransmission control entity of the different data signal in an area for storing a carrier identification number of the control signal corresponding to each of the different data signals.

According to the disclosed apparatus and method, it is possible to distinguish between process numbers used in retransmission control of different data signals.
These and other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings which illustrate preferred embodiments by way of example of the present invention.

It is a figure explaining the radio | wireless communications system which concerns on 1st Embodiment. It is the flowchart which showed operation | movement of the base station. It is the figure which showed the radio | wireless communications system which concerns on 2nd Embodiment. It is the 1 of the figure which showed the example of DL transmission of LTE-A. FIG. 2 is a second diagram illustrating an example of LTE-A DL transmission; FIG. 3-3 is a diagram illustrating an example of LTE-A DL transmission. It is a figure explaining distinction of a HARQ process number. It is the figure which showed the DL transmission example which can distinguish a HARQ process number. It is the figure which showed the example of HARQ entity identification information. It is the figure which showed the other example of HARQ entity identification information. It is the figure which showed the block example of the base station. It is the figure which showed the block example of the radio | wireless terminal. It is the flowchart which showed operation | movement of the base station. It is the figure which showed the hardware block example of the base station.

Hereinafter, embodiments will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a wireless communication system according to the first embodiment. As shown in FIG. 1, the wireless communication system includes a base station 1 and a wireless terminal 2. FIG. 1 also shows a DL radio subframe 3 transmitted from the base station 1 to the radio terminal 2.

The radio subframe 3 is divided into a control signal area 3a and a data signal area 3b. For example,

control signals

4a and 4b are stored in the control signal area 3a, and

data signals

5a and 5b to be transmitted to the wireless terminal 2 are stored in the data signal area 3b. The horizontal direction of the radio subframe 3 indicates frequency, and the vertical direction indicates time.

The control signal 4a is a control signal for the data signal 5a. The control signal 4a includes, for example, data arrangement information of the data signal 5a, a process number used for retransmission control of the data signal 5a, a modulation method of the data signal 5a, and other information related to control of the data signal 5a. Further, the control signal 4a has identification information for identifying an entity for retransmission control of the data signal 5a.

The control signal 4b is a control signal for the data signal 5b. Similarly to the control signal 4a, the control signal 4b is, for example, data arrangement information of the data signal 5b, a process number used in retransmission control of the data signal 5b, a modulation method of the data signal 5b, and other information related to control of the data signal 5b. have. Further, the control signal 4b has identification information for identifying an entity for retransmission control of the data signal 5b.

Retransmission control is, for example, HARQ, and one HARQ entity has eight HARQ processes. Therefore, when the retransmission control is HARQ, the process numbers of the

control signals

4a and 4b take values of 1 to 8, for example.

As an area for storing identification information, an area for storing a carrier identification number used for transmission of the data signals 5a and 5b is used. For example, the area for storing the identification information uses the CIF of the

control signals

4a and 4b.

The base station 1 has a transmitter 1a and a controller 1b as shown in FIG. The transmitter 1a can simultaneously transmit a plurality of data signals to the radio terminal 2 using a plurality of carriers (CC). For example, the transmission unit 1a can transmit a plurality of data signals to the wireless terminal 2 using CC # 1 and CC # 2 simultaneously.

When the control unit 1b transmits a plurality of different data signals transmitted from the transmission unit 1a to the wireless terminal 2 in one carrier, the control unit 1b stores a carrier identification number of a control signal corresponding to each of the different data signals. Includes identification information for identifying each retransmission control entity of different data signals.

For example, it is assumed that the transmission unit 1a includes two different data signals 5a and 5b to be transmitted to the wireless terminal 2 as illustrated in the wireless subframe 3 in FIG. In this case, the control unit 1b identifies the retransmission control entities of the

different data signals

5a and 5b in the areas storing the carrier identification numbers of the

control signals

4a and 4b corresponding to the

different data signals

5a and 5b, respectively. Include identification information.

More specifically, when the transmission unit 1a transmits two different data signals 5a and 5b with one CC # 1, the control unit 1b transmits the data signals 5a and 5b transmitted simultaneously with one CC # 1. In order to distinguish the HARQ entity, for example, “1” is stored in the CIF of the control signal 4a, and for example, “2” is stored in the CIF of the control signal 4b.

Thereby, the wireless terminal 2a can distinguish the HARQ process number of the data signals 5a and 5b transmitted by one CC # 1 based on the identification information included in the

control signals

4a and 4b. For example, in the wireless terminal 2, the process number of the identification information '1' identifying the HARQ entity is the process number of the data signal 5a, and the process number of the identification information '2' identifying the HARQ entity is the data number of the data signal 5b. It can be distinguished from the process number.

The wireless terminal 2 has a receiving unit 2a. The receiver 2a receives the

control signals

4a and 4b transmitted from the base station 1. The wireless terminal 2 can receive the data signals 5a and 5b based on the data arrangement information of the received

control signals

4a and 4b.

In addition, when the transmission part 1a does not transmit different data signals 5a and 5b simultaneously by one CC # 1, a carrier identification number is stored in CIF of the

control signals

4a and 4b. For example, it is assumed that the data signal 5a is transmitted by CC # 1, and the data signal 5b is transmitted by CC # 2. In this case, '# 1' for identifying CC # 1 is stored in the CIF of the control signal 4a corresponding to the data signal 5a, and CC # 2 is stored in the CIF of the control signal 4b corresponding to the data signal 5b. '# 2' for identifying is stored.

FIG. 2 is a flowchart showing the operation of the base station.
[Step S1] The control unit 1b of the base station 1 determines whether or not different data signals 5a and 5b are transmitted on one carrier (CC). When

different data signals

5a and 5b are transmitted by one CC, the control unit 1b proceeds to step S2. For example, when

different data signals

5a and 5b are transmitted by one CC # 1, as shown in FIG. 1, the control unit 1b proceeds to step S2. When the

different data signals

5a and 5b are transmitted by different CCs, the control unit 1b proceeds to step S3.

[Step S2] The control unit 1b stores, for example, identification information for identifying an entity for retransmission control in the CIF of the

control signals

4a and 4b. This is because CIF does not have to be used as an area for distinguishing CC # 1 and # 2 when data signals 5a and 5b are transmitted by one CC # 1.

[Step S3] The control unit 1b stores the carrier identification number in the CIF. For example, it is assumed that the data signal 5a is transmitted by CC # 1 and the data signal 5b is transmitted by CC # 2. In this case, for example, '# 1' indicating the carrier identification number of CC # 1 is stored in the CIF of the control signal 4a of the data signal 5a. For example, '# 2' indicating the carrier identification number of CC # 2 is stored in the CIF of the control signal 4b of the data signal 5b.

As described above, when the base station 1 transmits different data signals 5a and 5b to be transmitted to the wireless terminal 2 in one carrier (CC # 1), the control corresponding to each of the

different data signals

5a and 5b is performed. Identification information for identifying the respective retransmission control entities of the

different data signals

5a and 5b is included in the areas for storing the carrier identification numbers of the

signals

4a and 4b. The wireless terminal 2 receives the

control signals

4a and 4b transmitted from the base station 1. Thereby, the radio | wireless terminal 2 can distinguish the process number used by retransmission control of the

different data signals

5a and 5b with the identification information contained in the

control signals

4a and 4b.

[Second Embodiment]
Next, a second embodiment will be described in detail with reference to the drawings.
FIG. 3 is a diagram illustrating a wireless communication system according to the second embodiment. As shown in FIG. 2, the wireless communication system includes a base station 11 and a wireless terminal 12. The base station 11 and the wireless terminal 12 perform wireless communication by, for example, the LTE-A wireless method. The wireless terminal 12 is, for example, a mobile phone or a smartphone. Hereinafter, before describing the base station 11 and the wireless terminal 12, LTE-A will be described.

FIG. 4 is a first diagram showing an example of LTE-A DL transmission. FIG. 4 shows a radio subframe. The horizontal direction of the radio subframe indicates a frequency, and the vertical direction indicates time. One radio subframe length is 1 ms.

One radio subframe is divided into a control signal area and a data signal area as shown in FIG. A data signal transmitted from the base station to the wireless terminal is stored in the data signal area. A control signal for the data signal is stored in the control signal area. The control signal includes, for example, a data signal modulation method (for example, QPSK (Quadrature Phase Shift や Keying), 16QAM (Quadrature Amplitude Modulation)), a coding rate, and a time zone on which frequency axis. A radio parameter indicating whether or not it is arranged is included. Based on the received control signal, the wireless terminal can receive a data signal transmitted from the base station and perform processing such as demodulation and decoding.

In the example of FIG. 4, data signals 21 and 22 having low QoS data and high QoS data are stored in the data signal area. Although not shown, the control signal of the data signal 21 is stored in the upper control signal area of FIG. 4, and the control signal of the data signal 22 is stored in the lower control signal area of FIG.

In the LTE-A specification, it is possible to transmit a plurality of data with different characteristics such as data quality and delay requirement using one CC. For example, it is possible to transmit low QoS data and high QoS data with different QoS using one CC # 1.

However, in the LTE-A specification, one transport block is allocated to one wireless terminal in one CC. Therefore, a plurality of data is multiplexed on one transport block in one CC and transmitted to the wireless terminal as one data signal. For example, as shown in FIG. 4, the low QoS data and the high QoS data are multiplexed into one transport block and transmitted to the wireless terminal as one data signal 21 and one data signal 22.

In the LTE-A specification, one radio parameter is assigned to one data signal addressed to one radio terminal in one CC. For example, in the case of the example of FIG. 4, a predetermined modulation scheme, coding rate, and the like are applied to the data signal 21. In addition, a predetermined modulation scheme, coding rate, and the like are applied to the data signal 22.

Therefore, when a plurality of data having different characteristics are transmitted to the wireless terminal using one CC, each of the plurality of data cannot be transmitted in consideration of each data characteristic. For example, in the example of FIG. 4, transmission corresponding to the transmission rates of the low QoS data and the high QoS data cannot be performed for each of the low QoS data and the high QoS data.

FIG. 5 is a second diagram illustrating an example of LTE-A DL transmission. In LTE-A, a plurality of CCs can be allocated to wireless terminals and a plurality of different data signals can be transmitted.
FIG. 5 shows an example in which CC # 1 and # 2 are assigned to wireless terminals, a low QoS data signal is transmitted by CC # 1, and a high QoS data signal is transmitted by CC # 2.

As described in FIG. 4, in one CC, one radio parameter is assigned to one data signal addressed to one radio terminal. Therefore, for example, a modulation method with a high modulation degree can be applied to a CC # 1 low QoS data signal, and a modulation method with a low modulation degree can be applied to a CC # 2 high QoS data signal. it can. That is, by transmitting different data signals using different CCs, transmission can be performed in accordance with the characteristics of different data signals.

In the control signal area on the upper side of CC # 1 shown in FIG. 5, the control signal for the data signal in the lower data signal area is stored. In the lower control signal area of CC # 1, data signal control signals in the lower data signal area are stored.

Also, the control signal area on the upper side of CC # 2 stores the control signal of the data signal in the lower data signal area. In the lower control signal area of CC # 2, the control signal of the data signal in the lower data signal area is stored.

FIG. 6 is part 3 of a diagram showing an example of LTE-A DL transmission. In LTE-A, a control signal of a data signal transmitted by a plurality of CCs can be transmitted by, for example, one CC (cross carrier scheduling).

FIG. 6 shows radio subframes transmitted by CC # 1 and # 2. In the example of FIG. 6, the data signal 32a is transmitted by CC # 1, and the data signal 32b is transmitted by CC # 2.

The control signal 31a is a control signal for the data signal 32a. The control signal 31a has CIF. The CIF stores the carrier identification number of CC # 1 to which the data signal 32a is transmitted. For example, the carrier identification number of CC # 1 is “# 1”. Since the data signal 32a is transmitted by CC # 1, '# 1' is stored in the CIF of the control signal 31a.

In addition, the control signal 31a has wireless parameters such as data arrangement information of the data signal 32a and HARQ process number. Although not shown, the wireless parameter includes the modulation method and coding rate of the data signal 32a.

The control signal 31b is a control signal for the data signal 32b. The control signal 31b has CIF. The CIF stores the carrier identification number of CC # 2 to which the data signal 32b is transmitted. For example, the carrier identification number of CC # 2 is ‘# 2’. Since the data signal 32b is transmitted by CC # 2, '# 2' is stored in the CIF of the control signal 31b.

Further, the control signal 31b has radio parameters such as data arrangement information of the data signal 32b and a HARQ process number. Although not shown, the wireless parameters include the modulation scheme and coding rate of the data signal 32b.

In FIG. 6,

control signals

31a and 31b of

data signals

32a and 32b transmitted by a plurality of CCs # 1 and # 2 are transmitted by one CC # 1. Thereby, the wireless terminal only has to monitor the

control signals

31a and 31b of one CC # 1. That is, the wireless terminal does not have to monitor a plurality of CCs # 1 and # 2.

By the way, although not in the LTE-A specification, it is conceivable to transmit different data signals to the wireless terminal using one CC. It is conceivable that the modulation schemes and coding rates of different data signals are made different within one CC.

For example, in FIG. 6, it is conceivable to transmit the data signal 32b by CC # 1. However, in this case, the HARQ entity of the data signals 32a and 32b may not be distinguished.

Note that, when different data signals are transmitted to the wireless terminal using one CC, the load on the wireless terminal can be reduced. For example, as shown in FIG. 5, when different data signals are transmitted on different CCs, the radio terminal measures DL radio characteristics of two CCs # 1 and # 2, and notifies the base station. On the other hand, when different data signals are transmitted to the radio terminal using one CC, the radio terminal only needs to measure the DL radio characteristics of one CC and notify the base station, thereby reducing the load.

FIG. 7 is a diagram illustrating the distinction between HARQ process numbers. 7 indicates the HARQ process number of the data signal # 1. The numbers shown on the lower side indicate the HARQ process number of the data signal # 2. The HARQ process number is incremented by 1 from 1 to 8, for example, and circulates.

One frame of the HARQ process number shown in FIG. 7 corresponds to one radio subframe. Also, the crosses shown in FIG. 7 indicate that transmission of the data signal in the radio subframe corresponding to the HARQ process number has failed. Note that the data signals # 1 and # 2 are transmitted on the same CC. That is, it is assumed that the CIFs of the control signals of the data signals # 1 and # 2 have the same value.

For example, it is assumed that the base station transmits the data signal # 1 of the HARQ process number “1” to the wireless terminal. Then, it is assumed that the wireless terminal fails to receive the data signal # 1. In this case, the base station normally transmits the data signal # 1 in the radio subframe after 8 ms. However, if the load on the radio subframe is heavy and retransmission in the radio subframe is difficult, the next base station after 1 ms is transmitted. Retransmits in the next radio subframe.

For example, a dotted line frame 41 shown in FIG. 7 indicates a transmission failure of the HARQ process number “5” of the data signal # 2. When the base station determines that retransmission in the radio subframe after 8 ms is difficult, as shown on the right side of the dotted frame 41, the data signal of the HARQ process number “5” in the radio subframe after 1 ms. Retransmit # 2.

By the way, when the data signals # 1 and # 2 shown in FIG. 7 are transmitted with different CCs # 1 and # 2, the wireless terminal transmits the data signals # 1 and # 2 as indicated by dotted line frames 42 and 43, respectively. Even if the HARQ process numbers of the data signals # 1 and # 2 are the same, the HARQ process numbers of the data signals # 1 and # 2 can be distinguished. For example, as shown in FIG. 6, when each of the data signals 32a and 32b is transmitted using CC # 1 and CC # 2, the wireless terminal can perform the same HARQ process number of the data signals 32 and 32b. The HARQ process numbers of the data signals 32a and 32b can be distinguished.

However, when each of the data signals # 1 and # 2 shown in FIG. 7 is transmitted by the same CC # 1, the wireless terminal performs the HARQ process of the data signals # 1 and # 2 as indicated by the dotted frames 42 and 43, respectively. If the numbers are the same, it becomes impossible to distinguish which HARQ process number is the HARQ process number of which data signal # 1, # 2. For example, as shown in FIG. 1, when two

data signals

5a and 5b are transmitted simultaneously with one CC # 1, the wireless terminal transmits the data signal 5a when the HARQ process numbers of the data signals 5a and 5b are the same. , 5b HARQ process number cannot be distinguished.

Therefore, when the base station 11 shown in FIG. 2 transmits different data signals to be transmitted to the radio terminal 12 in one carrier, the base station 11 uses (diversifies) the CIF of the control signal so that the HARQ process number can be distinguished. To.

FIG. 8 is a diagram illustrating an example of DL transmission in which the HARQ process number can be distinguished. FIG. 8 shows radio subframes transmitted by two CCs # 1 and # 2. Data signals 52a to 52c shown in FIG. 8 indicate data signals transmitted from the base station 11 to the wireless terminal 12. The data signals 52a and 52b are transmitted by CC # 1, and the data signal 52c is transmitted by CC # 2.

The control signal 51a is a control signal for the data signal 52a. Although the control signal 51a has CIF, the base station 11 does not store the carrier identification number ‘# 1’ of CC # 1 that transmits the data signal 52a in the CIF of the control signal 51a. As shown in the control signal 51a, the base station 11 stores HARQ entity identification information for identifying the HARQ entity of the data signal 52a in the CIF.

In addition, the control signal 51a has wireless parameters such as data arrangement information of the data signal 52a and a HARQ process number. Although not shown, the wireless parameters include the modulation scheme and coding rate of the data signal 52a.

The control signal 51b is a control signal for the data signal 52b. Although the control signal 51b has CIF, the base station 11 does not store the carrier identification number “# 1” of CC # 1 that transmits the data signal 52b in the CIF of the control signal 51b. As shown in the control signal 51b, the base station 11 stores HARQ entity identification information for identifying the HARQ entity of the data signal 52b in the CIF.

In addition, the control signal 51b has wireless parameters such as data arrangement information of the data signal 52b and a HARQ process number. Although not shown, the wireless parameters include the modulation scheme and coding rate of the data signal 52b.

Different data signals 52a and 52b are transmitted by one CC # 1, but different radio parameters can be assigned. For example, the modulation schemes and coding rates of the

different data signals

52a and 52b can be made different.

The control signal 51c is a control signal for the data signal 52c. Although the control signal 51c has CIF, the base station 11 does not store the carrier identification number '# 2' of CC # 2 that transmits the data signal 52c in the CIF of the control signal 51c. As indicated by the control signal 51c, the base station 11 stores HARQ entity identification information for identifying the HARQ entity of the data signal 52c in the CIF.

Further, the control signal 51c has radio parameters such as data arrangement information of the data signal 52c and a HARQ process number. Although not shown, the wireless parameters include the modulation scheme and coding rate of the data signal 52c.

CIF has a 3-bit area. Accordingly, the base station 11 identifies HARQ entities of different data signals with the 3-bit HARQ entity identification information.
In the example of FIG. 8, the base station 11 transmits different data signals 52a and 52b using one CC # 1, and transmits a data signal 52c using another CC # 2.

Therefore, the HARQ entity identification information identifies the HARQ entity (HARQ process number) of the

different data signals

52a and 52b transmitted in one CC # 1, and the different data signal 52c transmitted in the other CC # 2. Identifies the HARQ entity (HARQ process number). That is, the HARQ entity identification information is 3-bit information obtained by combining the carrier identification numbers of CC # 1 and # 2 and information for identifying the HARQ entity.

FIG. 9 is a diagram showing an example of HARQ entity identification information. The value in the column of HARQ entity identification information shown in FIG. 9 indicates HARQ entity identification information stored in the CIF of the control signal. The value in the column of the carrier identification number indicates the carrier identification number of the CC to which the data signal is transmitted. The HARQ process group number indicates a value for identifying the HARQ entity of the data signal in each carrier. Since CIF has a 3-bit area, the HARQ entity identification information can be a maximum of eight.

For example, in FIG. 8, the data signals 52a and 52b are transmitted to the wireless terminal 12 using the same CC # 1. Accordingly, the HARQ entity identification information for identifying the HARQ entity of the data signals 52a and 52b is at least one of “1 to 4” in the example of FIG. That is, the HARQ entity of different data signals multiplexed on one CC is distinguished by the HARQ process group number.

More specifically, it is assumed that the base station 11 assigns the HARQ process group number “1” as a value for identifying the HARQ entity of the data signal 52a in FIG. Further, it is assumed that the base station 11 assigns the HARQ process group number “2” as the number for identifying the HARQ entity of the data signal 52b transmitted by the same CC # 1 as the data signal 52a. In this case, the HARQ entity identification information of the control signal 51a shown in FIG. Also, the HARQ entity identification information of the control signal 51b is “2”.

In FIG. 8, the data signal 52c is transmitted to the wireless terminal 12 by CC # 2. Accordingly, the HARQ entity identification information for identifying the HARQ entity of the data signal 52c is at least one of “5 to 8” in the example of FIG.

More specifically, it is assumed that the base station 11 assigns the HARQ process group number “5” as a value for identifying the HARQ entity of the data signal 52c. In this case, the HARQ entity identification information of the control signal 51c shown in FIG. 8 is “5”.

The base station 11 stores the information shown in FIG. 9 in a storage device such as a memory, for example. Similarly, the wireless terminal 12 stores the information shown in FIG. 9 in the storage device.
Therefore, even if the HARQ process number included in the control signals 51a to 51c received from the base station 11 has the same value, the wireless terminal 12 refers to the storage device storing the information shown in FIG. The HARQ entity of the data signal can be distinguished, and the HARQ process number can be distinguished. The wireless terminal 12 can also know the carrier identification number of the data to be received.

FIG. 10 is a diagram showing another example of HARQ entity identification information. In the example of FIG. 10, the base station 11 can transmit different data signals using four CCs. Further, in the example of FIG. 10, there are two different data signals that can be simultaneously transmitted by one CC.

Note that, when all the different data signals are transmitted by one CC as in the first embodiment, the value of the HARQ entity identification information and the value of the HARQ process group number are the same value, for example. This is because all the different data signals are transmitted by one CC, so that the carrier identification number information need not be included in the HARQ entity identification information.

For example, all the different data signals are transmitted in one CC in the carrier identification number column in FIG. For example, when all of the different data signals are transmitted by one CC # 1, the fields of the carrier identification number in FIG. 10 are all “# 1”. The HARQ process group number can take a value from 1 to 8. That is, the value of the HARQ entity identification information and the value of the HARQ process group number can be made the same. Note that the base station 11 can multiplex and transmit eight different data signals on one CC.

FIG. 11 is a diagram showing a block example of the base station. As shown in FIG. 11, the base station 11 includes a process management unit 61, multiplexed

signal generating units

62a, 62b, 63a, 64a, signal generating

units

63b, 64b, SW (switches) 65, 66, multiplexing units 67a to 67c, A modulation unit 68 and an RF (Radio-Frequency) unit 69 are included.

FIG. 11 shows a block for transmitting a control signal and a data signal to the wireless terminal 12. Therefore, the base station 11 actually has blocks shown in FIG. 11 corresponding to a plurality of wireless terminals.

The main carrier, second carrier, and third carrier shown in FIG. 11 correspond to three CCs. The multiplexed

signal generators

62a and 62b generate control signals and data signals transmitted on the main carrier. The multiplexed signal generator 63a and the signal generator 63b generate a control signal and a data signal transmitted on the second carrier or the main carrier. The multiplexed signal generation unit 64a and the signal generation unit 64b generate a control signal and a data signal that are transmitted on the third carrier or the main carrier.

The process management unit 61 generates HARQ entity identification information. For example, the process management unit 61 receives scheduling information from a scheduler (not shown), and generates HARQ entity identification information based on the scheduling information.

For example, the process management unit 61 can know to which CC # 1 and # 2 the data signals 52a to 52c shown in FIG. That is, the process management unit 61 can know whether or not to transmit different data signals 52a to 52c transmitted from the transmission unit (multiplexed signal generation unit 62a to RF unit 69) to the wireless terminal 12 in one carrier. . Then, the process management unit 61 generates HARQ entity identification information for identifying the HARQ entities of the data signals 52a to 52c with reference to, for example, the storage device in which the information illustrated in FIG. 9 or FIG. 10 is stored. Can do. The HARQ entity identification information generated by the process management unit 61 is output to the multiplexed

signal generation units

62a, 63a, and 64a.

In the above description, the process management unit 61 generates HARQ entity identification information. However, when a plurality of different data signals are not transmitted simultaneously using one carrier, a carrier identification number stored in the CIF is generated and is stored in each unit. Output.

The HARQ entity identification information or carrier identification number generated by the process management unit 61 is input to the multiple signal generation unit 62a. In addition, a user data control signal is input to the multiplexed signal generator 62a. The user data control signal is, for example, a signal indicating wireless parameter information. The multiplexed signal generation unit 62a multiplexes the input HARQ entity identification information or carrier identification number and the user data control signal to generate a control signal. For example, the multiple signal generator 62a generates the control signal 51a shown in FIG.

A user control signal, a common control signal, and user data are input to the multiple signal generator 62b. The user control signal has, for example, information on CC assigned to the wireless terminal 12. Therefore, the wireless terminal 12 can know the CC assigned to itself by the received user control signal. Note that the control signal does not always have to be transmitted to the wireless terminal 12, and is transmitted, for example, when the base station 11 and the wireless terminal 12 perform data communication for the first time or when the number of CCs is changed.

The common control signal is a system parameter indicating the transmission power, bandwidth, number of antennas, etc. of the base station 11, for example. The user data is user data transmitted to the wireless terminal 12. The multiplexed signal generator 62b multiplexes the input user control signal, common control signal, and user data to generate a data signal. For example, the multiple signal generator 62b generates the data signal 52a shown in FIG.

The HARQ entity identification information or carrier identification number generated by the process management unit 61 is input to the multiplexed signal generation unit 63a. In addition, a user data control signal is input to the multiplexed signal generator 63a. The multiplexed signal generation unit 63a multiplexes the input HARQ entity identification information or carrier identification number and the user data control signal to generate a control signal.

User data to be transmitted to the wireless terminal 12 is input to the signal generation unit 63b. The signal generation unit 63b generates a data signal from the input user data.
The HARQ entity identification information or the carrier identification number generated by the process management unit 61 is input to the multiplexed signal generation unit 64a. In addition, a user data control signal is input to the multiplexed signal generator 64a. The multiplexed signal generation unit 64a multiplexes the input HARQ entity identification information or carrier identification number and the user data control signal to generate a control signal.

User data to be transmitted to the wireless terminal 12 is input to the signal generator 64b. The signal generation unit 64b generates a data signal from the input user data.
The SW 65 switches the output destination of the control signal output from the multiple signal generation unit 63a and the data signal output from the signal generation unit 63b. For example, the SW 65 switches the output destination of the control signal and the data signal based on scheduling information output from a scheduler (not shown).

For example, it is assumed that the SW 65 receives scheduling information in which the control signal output from the multiple signal generation unit 63a and the data signal output from the signal generation unit 63b are transmitted on the main carrier. In this case, the SW 65 outputs the control signal output from the multiplexed signal generation unit 63a and the data signal output from the signal generation unit 63b to the multiplexing unit 67a. In addition, it is assumed that the SW 65 receives the scheduling information that the control signal output from the multiplexed signal generation unit 63a and the data signal output from the signal generation unit 63b are transmitted on the second carrier. In this case, the SW 65 outputs the control signal output from the multiplexed signal generator 63a and the data signal output from the signal generator 63b to the multiplexer 67b.

The multiple signal generation unit 64a, the signal generation unit 64b, and the SW 66 are the same as the multiple signal generation unit 63a, the signal generation unit 63b, and the SW 65, and description thereof is omitted. However, the output destination of the control signal and data signal of the SW 66 is the main carrier multiplexing section 67a or the third carrier multiplexing section 67c.

The multiplexing unit 67a multiplexes the control signals output from the multiplexed signal generation unit 62a and the

SWs

65 and 66, and stores them in the control signal area of the main carrier. The multiplexing unit 67a multiplexes the data signals output from the multiplexed signal generation unit 62b and the

SWs

65 and 66, and stores them in the data signal area of the main carrier.

The multiplexing unit 67b stores the control signal and data signal output from the SW 65 in the control signal area and data signal area of the second carrier. Multiplexer 67c stores the control signal and data signal output from SW 66 in the control signal area and data signal area of the third carrier.

The modulation unit 68 modulates the carrier output from the multiplexing units 67a to 67c. For example, the modulation unit 68 modulates the data signal of each carrier based on scheduling information output from a scheduler (not shown).

The RF unit 69 converts the carrier modulated by the modulation unit 68 into a radio frequency and outputs a radio signal to the antenna.
Note that the multiplexed signal generation unit 62a to the RF unit 69 shown in FIG. 11 correspond to, for example, the transmission unit 1a of FIG. Further, the process management unit 61 illustrated in FIG. 11 corresponds to, for example, the control unit 1b illustrated in FIG.

FIG. 12 is a diagram showing a block example of a wireless terminal. As shown in FIG. 12, the wireless terminal 12 includes an RF unit 81, a demodulation / decoding unit 82, separation units 83a to 83c, 85a, 85b, 86a, 87a,

SW

84a, 84b,

data extraction units

86b, 87b, and signal extraction. Part 88. Note that the signal output from the separation unit 85a illustrated in FIG. 12 corresponds to the signal input to the multiplexed signal generation unit 62b illustrated in FIG. The signal output from the separation unit 85b corresponds to the signal input to the multiple signal generation unit 62a illustrated in FIG. The signals output from the separation unit 86a and the data extraction unit 86b correspond to the signals input to the multiplexed signal generation unit 63a and the signal generation unit 63b illustrated in FIG. Furthermore, the signals output from the separation unit 87a and the data extraction unit 87b correspond to the signals input to the multiplexed signal generation unit 64a and the signal generation unit 64b shown in FIG.

The RF unit 81 down-converts the frequency of the radio signal received by the antenna to the baseband frequency.
Carrier information output from the signal extraction unit 88 is input to the demodulation / decoding unit 82. The carrier information is CC information assigned to the wireless terminal 12. The demodulation / decoding unit 82 separates the down-converted radio signal into a main carrier, a second carrier, and a third carrier based on the input carrier information.

The separation unit 83a separates control signals corresponding to different data signals included in the control signal area of the main carrier. For example, when three different data signals are transmitted on the main carrier, the control signal is separated into three. The separated control signals are output to the separation unit 85b, SW84a, or SW84b.

Also, the separation unit 83a separates different data signals included in the data signal area of the main carrier. For example, if three different data signals are transmitted on the main carrier, the data signal is separated into three. The separated data signals are output to the separation unit 85a, SW84a, or SW84b.

The separation unit 83b separates the control signal included in the control signal area of the second carrier and the data signal included in the data signal area. The separated control signal and data signal are output to the SW 84a.

The separation unit 83c separates the control signal included in the control signal area of the third carrier and the data signal included in the data signal area. The separated control signal and data signal are output to the SW 84b.

The SW 84a switches between the control signal and data signal output from the separation unit 83a and the control signal and data signal output from the separation unit 83b. For example, when the control signal and the data signal are output from the separation unit 83a, the SW 84a outputs the control signal and the data signal to the separation unit 86a and the data extraction unit 86b. In addition, when the control signal and the data signal are output from the separation unit 83b, the SW 84a outputs the control signal and the data signal to the separation unit 86a and the data extraction unit 86b.

SW84b is the same as SW84a. The SW 84b switches between the control signal and data signal output from the separation unit 83a and the control signal and data signal output from the separation unit 83c, and outputs them to the separation unit 87a and the data extraction unit 87b.

The separation unit 85a separates the user control signal, the common control signal, and the user data included in the data signal output from the separation unit 83a.
Separating section 85b separates the HARQ entity identification information or carrier identification number (not shown) included in the control signal output from separating section 83a and the user data control signal.

The separation unit 86a separates the HARQ entity identification information or carrier identification number included in the control signal output from the SW 84a and the user data control signal.
The data extraction unit 86b extracts user data from the data signal output from the SW 84a.

Separation section 87a separates the HARQ entity identification information or carrier identification number included in the control signal output from SW 84b and the user data control signal.

Separators

85b, 86a, and 87a have carrier identification numbers or HARQ entity identification information stored in the CIF of the control signal based on the control signals output from separators 83a to 83c. It can be judged whether there is. For example, when two control signals are output from the separation unit 83a, the

separation units

85b, 86a, and 87a can determine that different data signals are transmitted in one CC (main carrier). It can be determined that the entity identification information is stored. For example, when one control signal is output from the separation unit 83a and one control signal is output from the separation unit 83b, the

separation unit

85b, 86a, 87a stores a carrier recognition number in the CIF. Can be judged. That is, the wireless terminal 12 can determine whether the carrier identification number or the HARQ entity identification information is stored in the CIF of the control signal based on the number of control signals included in the received carrier.

The data extraction unit 87b extracts user data from the data signal output from the SW 84b.
The signal extraction unit 88 extracts CC information (carrier information) assigned to the radio terminal 12 included in the user control signal. The extracted carrier information is output to the demodulation / decoding unit 82. Note that the wireless terminal 12 can know which CC is wirelessly measured based on the carrier information.

Note that the RF unit 81 to the signal extraction unit 88 illustrated in FIG. 12 correspond to, for example, the reception unit 2a in FIG.
Further, the wireless terminal 12 can distinguish the HARQ entity of the user data output from the separation unit 85a and the

data extraction units

86b and 87b based on the HARQ entity identification information output from the

separation units

85b, 86a, and 87a. it can.

FIG. 13 is a flowchart showing the operation of the base station.
[Step S11] The process management unit 61 of the base station 11 determines whether or not to transmit a plurality of different data signals on one carrier (CC) based on, for example, scheduling information of the scheduler. For example, the process management unit 61 determines whether or not to transmit a plurality of different data signals with one carrier as in the examples illustrated in FIGS. 1 and 8. If the process management unit 61 determines to transmit a plurality of different data signals using one carrier, the process management unit 61 proceeds to step S13. If the process management unit 61 determines that a plurality of different data signals are not transmitted using one carrier (when it is determined that each of a plurality of different data signals is transmitted using a different carrier), the process management unit 61 proceeds to step S12.

[Step S12] The process management unit 61 stores the carrier identification number of the CC that transmits the data signal in the CIF of the control signal.
[Step S13] The process management unit 61 determines, for example, whether all of the different data signals are transmitted on one carrier based on scheduling information of the scheduler. If all the different data signals are transmitted by one CC, the process management unit 61 proceeds to step S14. On the other hand, when all the different data signals are not transmitted by one CC, the process management unit 61 proceeds to step S15.

For example, in the case of the example of FIG. 1, since all the

different data signals

5a and 5b are transmitted by one CC # 1, the process management unit 61 proceeds to step S14. In the case of the example of FIG. 8, since all of the different data signals 52a to 52c are not transmitted by one CC # 1, the process management unit 61 proceeds to step S15.

[Step S14] The process management unit 61 stores HARQ entity identification information corresponding to the HARQ process group number in the CIF of the control signal.
[Step S15] The process management unit 61 stores HARQ entity identification information in which the carrier identification number and the HARQ process group number are combined in the CIF of the control signal.

FIG. 14 is a diagram illustrating a hardware block example of the base station. As shown in FIG. 14, the base station 11 includes a processor 101, an HDD (Hard Disk Drive) 102, a RAM (Random Access Memory) 103, a BB (BaseBand) unit 104, an RF unit 105, an IF (InterFace) unit 106, and A bus 107 is provided.

The processor 101 is connected to the HDD 102, the RAM 103, the BB unit 104, the RF unit 105, and the IF unit 106 via the bus 107. The entire base station 11 is controlled by the processor 101. The processor 101 is, for example, a CPU (Central Processing Unit) or a DSP (Digital Signal Processing).

The HDD 102 stores an OS (Operating System) program and a program for including HARQ entity identification information for identifying the HARQ entity in the control signal. The RAM 103 temporarily stores part or all of data and programs used in various processes of the processor 101.

The BB unit 104 performs BB processing on data transmitted to the wireless terminal 12 and data received from the wireless terminal 12. The RF unit 105 performs radio processing on a signal transmitted to the wireless terminal 12 and a signal received from the wireless terminal 12.

The IF unit 106 communicates with a device existing in the core network such as an MME (Mobility Management Entity) via, for example, a wired connection.
The function of the transmission unit 1a illustrated in FIG. 1 is realized by the processor 101, the BB unit 104, and the RF unit 105, for example. The function of the control unit 1b is realized by the processor 101, for example.

The function of the process management unit 61 shown in FIG. The functions of the multiplexed signal generator 62 a to the modulator 68 are realized by the BB unit 104. The RF unit 69 corresponds to the RF unit 105.

The wireless terminal 12 also has the same hardware blocks as in FIG. However, the wireless terminal 12 does not have the IF unit 106. The function of the reception unit 2a illustrated in FIG. 1 is realized by, for example, the processor 101, the BB unit 104, and the RF unit 105.

As described above, when the base station 11 transmits different data signals to be transmitted to the wireless terminal 12 in one carrier, the base station 11 transmits each of the different data signals to the CIF of the control signal corresponding to each of the different data signals. HARQ entity identification information for identifying the HARQ entity is included. And the radio | wireless terminal 12 was made to receive the control signal transmitted from the base station 11. FIG. Thereby, the radio | wireless terminal 12 can manage and distinguish HARQ process number of a different data signal independently by the HARQ entity identification information stored in CIF contained in a control signal.

In addition, when the base station 11 transmits different data signals to be transmitted to the wireless terminal 12 in one carrier and transmits another different data signal in another carrier, the base station 11 uses different HARQ entity identification information. Added information to identify the carrier. As a result, the base station 11 can transmit a plurality of different data signals included in one carrier, and can transmit another different data signal included in another carrier. HARQ process numbers can be managed and distinguished independently.

Also, even when one CC is assigned to the radio terminal 12, the base station 11 can transmit different data signals in the same radio subframe on one CC, similarly to the case where a plurality of CCs are assigned. For example, the base station 11 does not need to perform management such that the HARQ process numbers do not match between different data signals, and can perform flexible data signal transmission scheduling in the time domain.

Also, since the wireless terminal 12 can reduce the number of CCs to be wirelessly measured, the power consumption of the wireless terminal 12 due to the wireless measurement process can be reduced. Further, since the radio terminal 12 can reduce the amount of radio measurement results reported to the base station 11, it can reduce the amount of radio resources used in the UL and power consumption caused by transmission in the UL.

Furthermore, in the wireless terminal 12 to which a plurality of CCs can be assigned, the CC carrier identification number is included in the CIF of the control signal, but when one CC is assigned, the CIF is used for other purposes. be able to. The base station 11 can use the CIF effectively by using this CIF for identifying the HARQ entity. Further, the base station 11 does not need to newly add a radio resource used to notify the radio terminal 12 of information for identifying the HARQ process number.

The above merely shows the principle of the present invention. In addition, many modifications and changes can be made by those skilled in the art, and the present invention is not limited to the precise configuration and application shown and described above, and all corresponding modifications and equivalents may be And the equivalents thereof are considered to be within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Base station

1a Transmission part

1b Control part 2 Wireless terminal 2a Reception part 3 Radio sub-frame 3a Control signal area 3b

Data signal area

4a,

4b Control signal

5a, 5b Data signal

Claims

In a base station that performs wireless communication with a wireless terminal,
A transmitter capable of transmitting a data signal to the wireless terminal using a plurality of carriers;
When the transmission unit transmits different data signals to be transmitted to the wireless terminal in one carrier, the different data signals are stored in an area for storing a carrier identification number of a control signal corresponding to each of the different data signals. A control unit including identification information for identifying each retransmission control entity;
A base station characterized by comprising:
When the transmission unit transmits the different data signal using a carrier other than the one carrier, the identification information includes information for identifying the other carrier. A base station according to item 1.
The base station according to claim 1, wherein the different data signals transmitted using the one carrier are assigned different radio parameters.
In a wireless terminal that performs wireless communication with a base station,
A receiving unit for receiving a control signal transmitted by the base station;
When the base station transmits different data signals included in one carrier, the control signal corresponding to each of the different data signals received by the receiving unit is used for retransmission control of the different data signals. A wireless terminal comprising identification information for identifying a process number.
In a wireless communication system having a base station and a wireless terminal,
The base station
A transmitter capable of transmitting a data signal to the wireless terminal using a plurality of carriers;
When the transmission unit transmits different data signals to be transmitted to the wireless terminal in one carrier, the different data signals are stored in an area for storing a carrier identification number of a control signal corresponding to each of the different data signals. A control unit including identification information for identifying each retransmission control entity, and
The wireless terminal is
A receiving unit for receiving the control signal transmitted by the base station;
A wireless communication system comprising:
In a wireless communication method of a base station that performs wireless communication with a wireless terminal,
A transmission unit transmits a data signal to the wireless terminal using a plurality of carriers,
When the transmission unit transmits different data signals to be transmitted to the wireless terminal in one carrier, the different data signals are stored in an area for storing a carrier identification number of a control signal corresponding to each of the different data signals. Include identification information that identifies each retransmission control entity,
A wireless communication method.
When the transmission unit transmits the different data signal using a carrier other than the one carrier, the identification information includes information for identifying the other carrier. The wireless communication method according to claim 6.
The wireless communication method according to claim 6, wherein different wireless parameters are assigned to the different data signals transmitted using the one carrier.
In a wireless communication method of a wireless terminal that performs wireless communication with a base station,
A receiving unit receives a control signal transmitted by the base station,
When the base station transmits different data signals included in one carrier, the control signal corresponding to each of the different data signals received by the receiving unit is used for retransmission control of the different data signals. A wireless communication method comprising identification information for identifying a process number.
In a wireless communication method of a wireless communication system having a base station and a wireless terminal,
The base station
A transmission unit transmits a data signal to the wireless terminal using a plurality of carriers,
When the transmission unit transmits different data signals to be transmitted to the wireless terminal in one carrier, the different data signals are stored in an area for storing a carrier identification number of a control signal corresponding to each of the different data signals. Including identification information identifying each retransmission control entity,
The wireless terminal is
Receiving the control signal transmitted by the base station;
A wireless communication method.