KR101414630B1 - Method of transmitting and receiving data in wireless communication system - Google Patents

Abstract

An aspect of the present invention relates to a method for transmitting data from a network of a wireless communication system to a terminal. The network adds the error detection code generated using the first identifier allocated to the UE to the scheduling information for data to be transmitted to the UE, and transmits the error detection code to the UE. In addition, the network transmits an error detection code generated using a second identifier allocated to the terminal to the terminal in addition to data to be transmitted to the terminal.

UTRAN, E-UTRAN, CRC, RNTI, error detection code, CRC

Description

[0001] The present invention relates to a method and apparatus for transmitting and receiving data in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a method of transmitting and receiving data in a wireless communication system.

In a wireless communication system using a multi-carrier scheme such as an Orthogonal Frequency Division Multiple Access (OFDMA) scheme or a Single Carrier-Frequency Division Multiplex Access (SC-FDMA) scheme, a radio resource is a set of continuous sub- Time-frequency region of < / RTI > One time-frequency domain is divided into a rectangle determined by time coordinates and subcarrier coordinates. That is, one time-frequency domain can be divided into a symbol on at least one time axis and a rectangle defined by subcarriers on a plurality of frequency axes. The time-frequency domain may be allocated to the uplink of a specific UE, or may be transmitted to a specific user in the downlink in a time-frequency domain. To define such a time-frequency domain in a two-dimensional space, the number of OFDM symbols in the time domain and the number of consecutive subcarriers starting at a position offset from the reference point in the frequency domain must be given.

In the Evolved Universal Mobile Telecommunications System (E-UMTS) system currently under discussion, a radio frame of 10 ms is used and one radio frame is composed of 20 subframes. That is, one subframe is 0.5 ms. One resource block is composed of one subframe and 12 subcarriers each of 15 kHz band. Also, one subframe may be composed of a plurality of OFDM symbols, and some of the plurality of OFDM symbols (e.g., the first symbol) may be used to transmit L1 / L2 control information.

FIG. 1 shows an example of a physical channel structure used in an E-UMTS system. One subframe includes an L1 / L2 control information transmission region (hatched portion) and a data transmission region (non-hatched portion) do.

2 is a diagram for explaining a general method of transmitting data in an E-UMTS. In E-UMTS, Hybrid Automatic Repeat reQuest (HARQ) technique, which is one of the data re-transmission techniques, is used to improve throughput and smooth communication.

2, downlink scheduling information (hereinafter, referred to as " downlink scheduling information ") is transmitted through a DL L1 / L2 control channel, for example, a physical downlink control channel (PDCCH) Quot; DL scheduling information "). The DL scheduling information includes a terminal identifier or a group identifier (UE Id or Group Id) of terminals, a resource assignment and a duration of assignment of radio resources allocated for transmission of downlink data, a modulation scheme, Transmission parameters such as payload size, MIMO related information, HARQ process information, redundancy version, and new data indicator (New Data Indicator).

The DL scheduling information can basically be transmitted through the DL L1 / L2 control channel even when retransmission is performed, and the information can be changed according to the channel condition. For example, if the channel condition is better than the initial transmission, the modulation scheme or payload size can be changed to transmit at a high bit rate. On the contrary, if the channel condition is poor, Lt; / RTI >

The BS transmits user data to the MS using a transmission parameter included in the DL scheduling information through a Physical Downlink Shared Channel (PDSCH), which is an allocated channel resource, e.g., a physical channel, through the DL scheduling information . The UE monitors the PDCCH every transmission time interval (TTI) and confirms the DL scheduling information to be received, and receives the user data transmitted from the base station using the DL scheduling information. The UE can confirm that the corresponding scheduling information is transmitted to the UE using the UE ID or the group ID included in the DL scheduling information. In the case of group scheduling using group identifiers, the UE checks scheduling information on a PDCCH using a group identifier assigned to a group to which the UE belongs, and the data transmitted on the PDSCH uses a terminal identifier And receives data after identifying the data to be transmitted to itself.

In other words, in the group scheduling scheme, the UE needs separate identifiers for receiving the scheduling information through the L1 / L2 control channel and receiving the data through the traffic channel. In this case, since a group identifier or a terminal identifier must be separately included in the scheduling information and the user data by a method such as a bitmap method, the amount of information to be transmitted is increased and wireless resources are wasted . Even if the group scheduling scheme is not used, the UE may need to receive scheduling information and user data using a separate UE identifier. Even in this case, the same problem as described in the group scheduling method may occur.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a data transmission and reception method capable of efficiently using radio resources in a wireless communication system.

According to another aspect of the present invention, there is provided a method for transmitting data to a terminal in a network of a wireless communication system. The network adds the error detection code generated using the first identifier allocated to the UE to the scheduling information for data to be transmitted to the UE, and transmits the error detection code to the UE. In addition, the network transmits an error detection code generated using a second identifier allocated to the terminal to the terminal in addition to data to be transmitted to the terminal.

Another aspect of the present invention relates to a method for a terminal to receive data transmitted from a network in a wireless communication system. The UE receives scheduling information transmitted through a control channel with an error detection code added thereto by the network and performs decoding on the error detection code added to the scheduling information using the first identifier allocated from the network do. When the decoding of the error detection code added to the scheduling information is successfully performed, the UE adds the error detection code to the network through the data channel using the scheduling information, And performs decoding on the error detection code added to the received data using the second identifier assigned to the terminal. When the decoding of the error detection code added to the received data is successfully performed, the terminal forwards the received data to an upper layer.

According to embodiments of the present invention, it is possible to reduce the amount of information to be transmitted in the wireless communication system, thereby effectively using wireless resources.

Hereinafter, the structure, operation and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which the technical features of the present invention are applied to an evolved universal mobile telecommunications system (E-UMTS).

3 is a diagram showing a network structure of an E-UMTS. The E-UMTS system evolved from the existing WCDMA UMTS system and is currently undergoing basic standardization work in the 3rd Generation Partnership Project (3GPP). E-UMTS is also called Long Term Evolution (LTE) system. The details of the technical specifications of UMTS and E-UMTS are given in [http://www.3gpp.org/ftp/Specs/2006-12/] and [http://www.3gpp.org/ftp /Specs/html-info/GanttChart-Level-2.htm].

Referring to FIG. 3, the E-UTRAN includes a base station (hereinafter abbreviated as 'eNode B' or 'eNB'). The eNBs are connected via the X2 interface. The eNB is connected to a User Equipment (hereinafter abbreviated as UE) through a wireless interface, and is connected to an EPC (Evolved Packet Core) through an S1 interface. The EPC includes a Mobility Management Entity (MME) / System Architecture Evolution (SAE) gateway.

The layers of the radio interface protocol between the UE and the network are classified into L1 (first layer), L1 (second layer), and the like based on the lower three layers of the Open System Interconnection (OSI) A physical layer belonging to a first layer provides an information transfer service using a physical channel, and a physical layer (physical layer) A Radio Resource Control (RRC) layer located at Layer 3 controls the radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the network. The RRC layer may be distributed to the network nodes such as the Node B and the AG, or may be located independently of the Node B or the AG.

4 is a schematic configuration diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN). In Figure 4, the hatching shows the functional entities of the user plane and the unhatched portion shows the functional entities of the control plane.

5A and 5B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN, wherein FIG. 5A is a control plane protocol diagram and FIG. 5B is a user plane protocol diagram . The wireless interface protocols of FIGS. 5A and 5B horizontally comprise a physical layer, a data link layer, and a network layer, and vertically, a user plane (User Plane) and a control plane (Control Plane) for transmitting control signals (Signaling). The protocol layers of FIG. 5A and FIG. 5B may be classified into L1 (first layer), L2 (second layer), and L2 (third layer) based on the lower three layers of the Open System Interconnection L3 (third layer).

The physical layer as the first layer provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to a medium access control layer (upper layer) through a transport channel, and data between the medium access control layer and the physical layer moves through the transport channel. Data is transferred between the different physical layers, that is, between the transmitting side and the receiving side physical layer through the physical channel. In the E-UMTS, the physical channel is modulated by an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and uses time and frequency as radio resources.

The Medium Access Control (MAC) layer of the second layer provides a service to a radio link control layer that is an upper layer through a logical channel. The second layer of Radio Link Control (RLC) layer supports the transmission of reliable data. The PDCP layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit data transmitted using IP packets such as IPv4 or IPv6 in a relatively low bandwidth wireless region. do.

The radio resource control (RRC) layer located at the bottom of the third layer is defined only in the control plane and is configured to perform a configuration of a radio bearer (RB) -configuration and release of the logical channel, the transport channel, and the physical channel. At this time, the RB means a service provided by the second layer for data transmission between the UE and the UTRAN.

The downlink transmission channel for transmitting data from the network to the terminal includes a BCH (Broadcast Channel) for transmitting system information, a PCH (Paging Channel) for transmitting a paging message, and a downlink SCH ). In case of a traffic or control message of a downlink multicast or broadcast service, it may be transmitted through a downlink SCH, or may be transmitted via a separate downlink multicast channel (MCH). On the other hand, the uplink transmission channel for transmitting data from the UE to the network includes RACH (Random Access Channel) for transmitting an initial control message and an uplink SCH (Shared Channel) for transmitting user traffic or control messages.

A logical channel mapped to a transport channel is a broadcast channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), a multicast traffic channel ).

In the E-UMTS system, the OFDM scheme is used in the downlink and the single carrier-frequency division multiple access (SC-FDMA) scheme is used in the uplink. The OFDM system, which is a multi-carrier scheme, is a system for allocating resources in a plurality of subcarriers by grouping a part of a carrier wave, and uses OFDMA (Orthogonal Frequency Division Multiple Access) as a connection scheme.

FIG. 6 illustrates a data frame structure for explaining an embodiment of the present invention.

Referring to FIG. 6, a BS adds an error detection code generated using a first identifier allocated to the UE to DL scheduling information for data transmission to a UE, and transmits the error detection code to the UE through a PDCCH. Thereafter, the BS adds the error detection code generated using the second identifier assigned to the MS to the data to be transmitted to the MS, and transmits the error detection code to the MS via the PDSCH. That is, in the embodiment of FIG. 6, when the BS transmits DL scheduling information to the UE through the PDCCH, the UE does not include the first identifier allocated to the UE as part of the DL scheduling information, And adds the error detection code generated using the identifier to the DL scheduling information and transmits the DL scheduling information. Even when the base station transmits user data to the mobile station through the PDSCH, the error detection code is generated using the second identifier instead of including the second identifier as partial data of the user data, And transmits the data after adding it to the user data.

The error detection code means a code added by the transmitting side so that the receiving side can detect whether or not an error has occurred in the data transmitted from the transmitting side to the receiving side in the communication system. The most widely used error detection codes are CRC (Cyclic Redundancy Check) codes, and algorithms for generating CRC codes are well known. One method of generating a CRC code using a specific terminal identifier is an example of generating a CRC code using the terminal identifier as an input value of an algorithm for generating a CRC code. It is also possible to use a different kind of error detection code in addition to the CRC code.

The terminal receives data from the base station using the first identifier and the second identifier allocated to the terminal. Specifically, the BS monitors the PDCCH using the first identifier at every transmission time interval (TTI) or at a designated time to check whether there is DL scheduling information transmitted to the BS. At this time, if the UE successfully decodes the CRC code added to the DL scheduling information using the first identifier, it can know that the corresponding scheduling information is information transmitted to the UE. After recognizing that the scheduling information received through the DPCCH by the CRC check is information for the UE, the UE receives the data transmitted from the BS through the DPSCH using the received scheduling information. The UE attempts to decode the CRC code of the data received through the DPSCH using the second identifier, and if the decoding is successful, the UE determines that the data is finally transmitted to the UE. At this time, the MS transmits an ACK to the BS with respect to the data received through the DPSCH. If decoding using the second identifier fails, the terminal discards the corresponding data.

In another embodiment, the base station generates DL scheduling information transmitted on the DPCCH and CRC code added to data transmitted on the DPSCH using the first identifier allocated to the UE, adds the DL scheduling information to the DL scheduling information and data, To the terminal. Meanwhile, the BS includes the second identifier allocated to the MS in the data transmitted through the DPSCH. The UE attempts CRC code decoding on the DL scheduling information transmitted on the DPCCH using the first identifier, and when the decoding is successfully performed, the UE receives the data on the DPSCH. The UE attempts CRC code decoding on the data received through the DPSCH using the first identifier and checks if the second identifier is included in the received data if decoding is successful. If the second identifier is included in the received data, the terminal determines the corresponding data as data transmitted to the terminal.

The embodiments of the present invention as described above can be applied to data transmission / reception between a base station and a terminal using two identifiers assigned to the terminal. For example, in a wireless communication system to which group scheduling is applied, a group RNTI for identifying a group to which the UE belongs and a UE RNTI for identifying the UE are allocated to one UE. At this time, the group identifier may be used as the first identifier described in the above embodiments, and the terminal identifier may be used as the second identifier.

In UMTS or E-UMTS, the terminal identifier is used in the name of Radio Network Temporary Identity (RNTI). The RNTI has a dedicated RNTI (Dedicated RNTI) and a common RNTI (Common RNTI). The dedicated RNTI means an RNTI which is allocated from the network when a specific terminal enters the network and is registered in a specific base station, and is used for communication with the network. The common RNTI refers to an RNTI that is temporarily allocated to a terminal when the information of the terminal is not registered in a specific base station because the terminal does not enter the network. The common RNTI is used for transmission of information commonly used by a plurality of terminals such as system information. For example, RA-RNTI or Temporary C-RNTI (Temporary C-RNTI) allocated to a terminal that transmitted a random access preamble to a base station in a random access procedure is a common RNTI. The dedicated RNTI may be allocated to a specific terminal by a base station or a CN. That is, the base station can allocate a dedicated RNTI to a specific terminal using an RRC connection setup message such as an RRC connection setup message or an RRC connection setup message in the RRC connection setup process. The core network can set a dedicated RNTI to a specific terminal using a NAS setup message such as an ATTACH ACCEPT message or a TRACKING AREA UPDATE ACCEPT message.

When a specific UE has both a common RNTI and a dedicated RNTI such as an RA-RNTI or a temporary C-RNTI in a random access procedure through a random access channel (RACH), the above- Accordingly, the base station can transmit the message to the terminal. At this time, the common RNTI can be used as the first identifier described in the above embodiments, and the dedicated identifier can be used as the second identifier. The opposite is also possible. In this case, the PDCCH or the PDSCH used in the embodiments of the present invention may be changed to other channels.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

In this document, embodiments of the present invention have been described mainly on the data transmission / reception relationship between the terminal and the base station. The specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. The term 'terminal' may be replaced with terms such as User Equipment (UE), Mobile Station (MS), and Mobile Subscriber Station (MSS).

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of firmware or software implementation, the data transmission / reception method in the wireless communication system according to an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, and the like for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

1 shows an example of a physical channel structure used in an E-UMTS system.

2 is a diagram for explaining a general method of transmitting data in an E-UMTS.

3 is a diagram showing a network structure of an E-UMTS.

4 is a schematic configuration diagram of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).

5A and 5B illustrate a structure of a radio interface protocol between a UE and an E-UTRAN, wherein FIG. 5A is a control plane protocol diagram and FIG. 5B is a user plane protocol diagram .

FIG. 6 illustrates a data frame structure for explaining an embodiment of the present invention.

Claims (14)

A method for a base station of a wireless communication system to transmit data to a terminal, Comprising: receiving a random access preamble from a terminal; Allocating a Temporary C-Radio Network Temporary Identifier (C-RNTI) for temporarily identifying the UE; Transmitting a Physical Downlink Control Channel (PDCCH) including a cyclic redundancy check (CRC) scrambled with a random access (RA) -RNTI; And And transmitting a Physical Downlink Shared CHannel (PDSCH) including the allocated temporary C-RNTI, Wherein the RA-RNTI is an identifier that can be shared by the terminal and the other terminal when the terminal that is different from the terminal also transmits the random access preamble to the base station in the receiving step. The method of claim 1, A channel monitoring unit for monitoring a channel at a predetermined transmission time interval using the RA-RNTI to detect the downlink physical control channel transmitted from the base station, and for transmitting the CRC included in the transmitted downlink physical control channel to the RA- RNTI, < / RTI > 3. The method of claim 2, And discarding the downlink physical control channel if decoding of the CRC using the RA-RNTI is unsuccessful. 3. The method of claim 2, And decoding the downlink physical data channel upon successful decoding of the CRC using the RA-RNTI. The method of claim 1, And if the decoding of the downlink physical data channel is successful, checking the value of the temporary C-RNTI included in the downlink physical data channel. The method of claim 1, And if the decoding of the downlink physical data channel is successful, transmitting a predetermined message to the base station in accordance with the scheduling information. A method for a terminal to receive data from a base station in a wireless communication system, Transmitting a random access preamble to the base station; Receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared CHannel (PDSCH) including a CRC from the base station; And And decoding the CRC included in the downlink physical control channel using a RA-RNTI (Random Access-Network Temporary Identifier) The downlink physical data channel includes a temporary C-RNTI (Temporary C-RNTI) allocated by the base station to temporarily identify the UE that has transmitted the random access preamble, The CRC included in the downlink physical control channel is scrambled with the RA-RNTI, and in the transmitting step, when a terminal different from the terminal also transmits the random access preamble to the base station, the RA- Wherein the RNTI is an identifier that can be shared between the terminal and the other terminal. 8. The method of claim 7, Further comprising monitoring the channel at a predetermined transmission time interval using the RA-RNTI to detect the downlink physical control channel transmitted by the base station. 8. The method of claim 7, And discarding the downlink physical control channel if decoding of the CRC using the RA-RNTI fails. 8. The method of claim 7, Further comprising decoding the downlink physical data channel upon successful decoding of the CRC using the RA-RNTI. 8. The method of claim 7, And if the decoding of the downlink physical data channel is successful, checking the value of the temporary C-RNTI included in the downlink physical data channel. 8. The method of claim 7, And if the decoding of the downlink physical data channel is successful, transmitting a predetermined message to the base station in accordance with the scheduling information. A computer-readable recording medium on which a program for executing the method according to any one of claims 1 to 6 is recorded. A computer-readable recording medium storing a program for executing the method according to any one of claims 7 to 12.

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