WO2016175029A1

WO2016175029A1 - Wireless communication device and user terminal

Info

Publication number: WO2016175029A1
Application number: PCT/JP2016/061936
Authority: WO
Inventors: 智春山▲崎▼; 空悟守田; 直久松本; 童　方偉; 宏行浦林; 真人藤代; 剛洋榮祝
Original assignee: 京セラ株式会社
Priority date: 2015-04-28
Filing date: 2016-04-13
Publication date: 2016-11-03

Abstract

A wireless communication device according to one embodiment performs multiplex communication. The wireless communication device generates a concatenated bit string by concatenating a plurality of bit strings respectively formed from the bit strings of a plurality of UE. The wireless communication device uses the same wireless resource to transmit a wireless signal including the concatenated bit string to the plurality of UE.

Description

Wireless communication apparatus and user terminal

The present invention relates to a wireless communication device and a user terminal in a wireless communication system.

In recent years, various multiplex communication technologies have been put into practical use in order to effectively utilize limited radio resources in a radio communication system (see, for example, Non-Patent Document 1).

The wireless communication apparatus according to one embodiment performs multiplex communication. The wireless communication apparatus generates a concatenated bit string by concatenating a plurality of bit strings composed of respective bit strings of a plurality of user terminals, and uses the same radio resource to transmit a radio signal including the concatenated bit string. A transmission unit configured to transmit to the plurality of user terminals.

The user terminal according to one embodiment is a user terminal included in a plurality of user terminals. The user terminal is transmitted from a radio communication device using the same radio resource, and receives a radio signal including a concatenated bit string composed of the bit strings of the plurality of user terminals, and the user terminal from the concatenated bit string A control unit that extracts a bit string of the user terminal.

It is a figure which shows the structure of a LTE system. It is a protocol stack figure of the radio | wireless interface in a LTE system. It is a block diagram of the radio | wireless frame used with a LTE system. It is a block diagram of UE. It is a block diagram of eNB. It is a figure for demonstrating the outline | summary of 1st and 2nd embodiment. It is a figure for demonstrating the application scenario 1 which concerns on 1st Embodiment. 7A shows a comparative example in the application scenario 1, and FIG. 7B shows an embodiment in the application scenario 1. It is a figure which shows the Example in the application scenario 2. FIG. FIG. 5 is a diagram for explaining “Bit-wise multiplexing” according to the first embodiment. It is a figure which shows an example of the operation | movement sequence which concerns on 1st Embodiment. It is a figure which shows an example of the operation | movement sequence in the pattern 1 of the HARQ ACK / NACK resource which concerns on 1st Embodiment. It is a figure for demonstrating the application scenario which concerns on 2nd Embodiment. It is a figure for demonstrating "Bit-wise multiplexing" concerning 2nd Embodiment. It is a figure which shows an example of the operation | movement sequence which concerns on 2nd Embodiment.

[Wireless communication system]
Below, the outline | summary of the LTE (Long Term Evolution) system which is a radio | wireless communications system which concerns on embodiment is demonstrated. The LTE system is a wireless communication system based on the 3GPP (Third Generation Partnership Project) standard.

(1) Configuration of Radio Communication System FIG. 1 is a diagram illustrating a configuration of an LTE system. As shown in FIG. 1, the LTE system includes a UE (User Equipment) 100, an E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) 10, and an EPC (Evolved Packet Core) 20.

UE 100 corresponds to a user terminal. The UE 100 is a mobile communication device, and performs radio communication with a cell (serving cell). The configuration of the UE 100 will be described later.

E-UTRAN 10 corresponds to a radio access network. The E-UTRAN 10 includes an eNB 200 (evolved Node-B). The eNB 200 corresponds to a base station. The eNB 200 is connected to each other via the X2 interface. The configuration of the eNB 200 will be described later.

The eNB 200 manages one or a plurality of cells and performs radio communication with the UE 100 that has established a connection with the own cell. The eNB 200 has a radio resource management (RRM) function, a routing function of user data (hereinafter simply referred to as “data”), a measurement control function for mobility control / scheduling, and the like. “Cell” is used as a term indicating a minimum unit of a radio communication area, and is also used as a term indicating a function of performing radio communication with the UE 100.

The EPC 20 corresponds to a core network. The EPC 20 includes an MME (Mobility Management Entity) / S-GW (Serving-Gateway) 300. MME performs various mobility control etc. with respect to UE100. The S-GW performs data transfer control. The MME / S-GW 300 is connected to the eNB 200 via the S1 interface. The E-UTRAN 10 and the EPC 20 constitute a network.

(2) Configuration of Radio Interface FIG. 2 is a protocol stack diagram of a radio interface in the LTE system. As shown in FIG. 2, the radio interface protocol is divided into the first to third layers of the OSI reference model, and the first layer is a physical (PHY) layer. The second layer includes a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. The third layer includes an RRC (Radio Resource Control) layer.

The physical layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control signals are transmitted between the physical layer of the UE 100 and the physical layer of the eNB 200 via a physical channel.

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ), random access procedure, and the like. Data and control signals are transmitted between the MAC layer of the UE 100 and the MAC layer of the eNB 200 via a transport channel. The MAC layer of the eNB 200 includes a scheduler that determines an uplink / downlink transport format (transport block size, modulation / coding scheme (MCS)) and an allocation resource block to the UE 100.

The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the physical layer. Data and control signals are transmitted between the RLC layer of the UE 100 and the RLC layer of the eNB 200 via a logical channel.

The PDCP layer performs header compression / decompression and encryption / decryption.

The RRC layer is defined only in the control plane that handles control signals. Messages for various settings (RRC messages) are transmitted between the RRC layer of the UE 100 and the RRC layer of the eNB 200. The RRC layer controls the logical channel, the transport channel, and the physical channel according to establishment, re-establishment, and release of the radio bearer. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in the RRC connected mode, otherwise, the UE 100 is in the RRC idle mode.

The NAS (Non-Access Stratum) layer located above the RRC layer performs session management and mobility management.

(3) Overview of LTE Lower Layer FIG. 3 is a configuration diagram of a radio frame used in the LTE system. In the LTE system, Orthogonal Division Multiple Access (OFDMA) is applied to the downlink, and SC-FDMA (Single Carrier Frequency Multiple Access) is applied to the uplink.

As shown in FIG. 3, the radio frame is composed of 10 subframes arranged in the time direction. Each subframe is composed of two slots arranged in the time direction. The length of each subframe is 1 ms, and the length of each slot is 0.5 ms. Each subframe includes a plurality of resource blocks (RB) in the frequency direction and includes a plurality of symbols in the time direction. Each resource block includes a plurality of subcarriers in the frequency direction. One symbol and one subcarrier constitute one resource element (RE). Further, among radio resources (time / frequency resources) allocated to the UE 100, a frequency resource can be specified by a resource block, and a time resource can be specified by a subframe (or slot).

In the downlink, the section of the first few symbols of each subframe is an area mainly used as a physical downlink control channel (PDCCH) for transmitting a downlink control signal. Details of the PDCCH will be described later. The remaining part of each subframe is an area that can be used mainly as a physical downlink shared channel (PDSCH) for transmitting downlink data.

The eNB 200 basically transmits a downlink control signal (DCI: Downlink Control Information) to the UE 100 using the PDCCH, and transmits downlink data to the UE 100 using the PDSCH. The downlink control signal carried by the PDCCH includes uplink SI (Scheduling Information), downlink SI, and TPC bits. The uplink SI is scheduling information (UL grant) related to allocation of uplink radio resources, and the downlink SI is scheduling information related to allocation of downlink radio resources. The TPC bit is information instructing increase / decrease in uplink transmission power. The eNB 200 includes the CRC bits masked with the identifier (RNTI: Radio Network Temporary Identifier) of the destination UE 100 in the downlink control signal in order to identify the destination UE 100 of the downlink control signal. Each UE 100 performs blind decoding (blind decoding) on the PDCCH by demasking the CRC bits with the RNTI of the own UE for the downlink control signal that may be destined for the own UE, and the downlink control signal addressed to the own UE. Is detected. The PDSCH carries downlink data using downlink radio resources (resource blocks) indicated by the downlink SI.

In the uplink, both end portions in the frequency direction in each subframe are regions used mainly as physical uplink control channels (PUCCH: Physical Uplink Control Channels) for transmitting uplink control signals. The remaining part of each subframe is an area that can be used mainly as a physical uplink shared channel (PUSCH) for transmitting uplink data.

The UE 100 basically transmits an uplink control signal (UCI: Uplink Control Information) to the eNB 200 using the PUCCH, and transmits uplink data to the eNB 200 using the PUSCH. Uplink control signals carried by the PUCCH include CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indicator), scheduling request (SR: Scheduling Request), and HARQ ACK / NACK. The CQI is an index indicating downlink channel quality, and is used for determining an MCS to be used for downlink transmission. The PMI is an index indicating a precoder matrix that is preferably used for downlink transmission. RI is an index indicating the number of layers (number of streams) that can be used for downlink transmission. SR is information for requesting allocation of PUSCH resources. HARQ ACK / NACK is delivery confirmation information indicating whether downlink data has been correctly received.

(4) Outline of HARQ HARQ is a technique for improving the communication quality of a transmission path by combining ARQ and error correction. In particular, it is possible to improve the quality by combining the reception result of the initial transmission and the reception result of the retransmission upon retransmission.

An example of the retransmission method will be described. In the UE 100, when the received data cannot be decoded correctly, in other words, when a CRC (Cyclic Redundancy Check) error occurs, the UE 100 transmits “HARQ NACK” to the eNB 200. The eNB 200 that has received “HARQ NACK” retransmits the data. On the other hand, when the received data can be correctly decoded in the UE 100, in other words, when no CRC error occurs, the UE 100 transmits “HARQ ACK” to the eNB 200.

As an example of the HARQ method, there is chase combining. Chase combining is a method of transmitting the same data in initial transmission and retransmission, and is a method of improving gain by combining initial transmission data and retransmission data in retransmission. As another example of the HARQ system, there is IR (Incremental redundancy). IR increases redundancy, and by transmitting parity bits in retransmission, the redundancy is increased in combination with the initial transmission, and the quality is improved by an error correction function.

(5) Configuration of user terminal FIG. 4 is a block diagram of the UE 100 (user terminal). As illustrated in FIG. 4, the UE 100 includes a reception unit 110, a transmission unit 120, and a control unit 130.

The receiving unit 110 performs various types of reception under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

The transmission unit 120 performs various transmissions under the control of the control unit 130. The transmission unit 120 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output from the control unit 130 into a radio signal and transmits it from the antenna.

The control unit 130 performs various controls in the UE 100. The control unit 130 includes a processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor includes a baseband processor that performs modulation / demodulation and encoding / decoding of the baseband signal, and a CPU (Central Processing Unit) that executes various processes by executing programs stored in the memory. The processor may include a codec that performs encoding / decoding of an audio / video signal. The processor executes the above-described processing and processing described later.

(6) Configuration of Base Station FIG. 5 is a block diagram of the eNB 200 (base station). As illustrated in FIG. 5, the eNB 200 includes a transmission unit 210, a reception unit 220, a control unit 230, and a backhaul communication unit 240.

The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output from the control unit 230 into a radio signal and transmits it from the antenna.

The receiving unit 220 performs various types of reception under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

The control unit 230 performs various controls in the eNB 200. The control unit 230 includes a processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor includes a baseband processor that performs modulation / demodulation and encoding / decoding of the baseband signal, and a CPU (Central Processing Unit) that executes various processes by executing programs stored in the memory. The processor executes the above-described processing and processing described later.

The backhaul communication unit 240 is connected to the neighboring eNB 200 via the X2 interface, and is connected to the MME / S-GW 300 via the S1 interface. The backhaul communication unit 240 is used for communication performed on the X2 interface, communication performed on the S1 interface, and the like.

[First Embodiment]
The first embodiment will be described below.

(1) Overview of First Embodiment First, an overview of the first embodiment will be described. FIG. 6 is a diagram for explaining the outline of the first embodiment.

As illustrated in FIG. 6, the eNB 200 performs downlink multiplex communication with a plurality of UEs 100 (UE100 # 1 to UE100 # 3). In the first embodiment, the eNB 200 corresponds to a radio communication device that performs multiplex communication with a plurality of user terminals.

The control unit 230 of the eNB 200 generates a concatenated bit string by concatenating a plurality of bit strings composed of the bit strings of the UEs 100 # 1 to UE100 # 3. The transmission unit 210 of the eNB 200 transmits a radio signal including the concatenated bit string to the UE 100 # 1 to the UE 100 # 3 using the same radio resource.

The receiving unit 110 of the UE 100 # 1 receives a radio signal that is transmitted from the eNB 200 using the same radio resource and includes a concatenated bit string that includes each bit string of the UE 100 # 1 to UE100 # 3. The control unit 130 of the UE 100 # 1 extracts the bit string of itself (UE 100 # 1) from the concatenated bit string. Similarly to UE 100 # 1, UE 100 # 2 and UE 100 # 3 also receive the concatenated bit string and extract its own bit string from the concatenated bit string.

(2) Application scenario according to the first embodiment An application scenario according to the first embodiment will be described below.

(2.1) Application scenario 1
FIG. 7 is a diagram for explaining the application scenario 1. Application scenario 1 is a scenario in which the channel state of each UE 100 is good and each UE 100 transmits and receives a small amount of data to and from the eNB 200. A scenario in which the channel state is good includes a scenario in which each UE 100 is located near the cell center of the eNB 200. Examples of the scenario for transmitting and receiving a small amount of data include a scenario in which M2M (Machine to Machine) communication or VoIP (Voice over Internet Protocol) communication is performed, or a scenario in which the UE 100 periodically transmits and receives a keep alive signal.

FIG. 7A shows a comparative example in the application scenario 1. As illustrated in FIG. 7A, the eNB 200 allocates one resource block (RB) to each UE 100. Further, the eNB 200 applies a low modulation / coding scheme (MCS) to each UE in order to transmit a small amount of data to each UE 100. In the example of FIG. 7A, the eNB 200 assigns RB # 1 to the UE100 # 1 and applies MCS0. The eNB 200 assigns RB # 2 to the UE100 # 2 and applies MCS0. The eNB 200 assigns RB # 3 to the UE 100 # 3 and applies MCS0.

As described above, in the comparative example in the application scenario 1, although the channel state of each UE is good, a low MCS is applied, so that the good channel state cannot be utilized.

FIG. 7B shows an example in the application scenario 1. As shown in FIG. 7B, the eNB 200 generates a concatenated bit string by concatenating a plurality of bit strings composed of bit strings of each UE, and uses the same radio resource (RB # 1) to generate the concatenated bit string. The radio signal containing is transmitted to each UE. In the following, such a multiplexing method is referred to as “Bit-wise multiplexing” or “code block multiplexing”. Each UE 100 receives a radio signal including a concatenated bit string transmitted from the eNB 200 using RB # 1, and extracts its own bit string from the concatenated bit string. The “concatenated bit string” may be referred to as a “concatenated code block”.

Here, the eNB 200 applies MCS corresponding to the channel state of each UE, that is, high MCS. In the example of FIG. 7A, the eNB 200 assigns RB # 1 to each UE and applies MCS14. For this reason, the embodiment in the application scenario 1 can effectively use a good channel state as compared with the comparative example.

Thus, in the embodiment in the application scenario 1, the number of resource blocks used for transmission of the concatenated bit string is smaller than the total number of UEs 100. In the example of FIG. 7A, the eNB 200 arranges the concatenated bit string in one resource block, and transmits the concatenated bit string using one resource block. Each UE 100 receives a concatenated bit string using one resource block. Therefore, since the amount of radio resources used is reduced compared to the comparative example, the eNB 200 can accommodate more UEs 100.

Furthermore, it is known that the longer the bit length to be encoded, the higher the error correction capability. For this reason, by performing error correction coding on the concatenated bit string at once, the error correction capability can be improved and a higher coding gain can be obtained.

(2.2) Application scenario 2
FIG. 8 is a diagram illustrating an example in the application scenario 2. In FIG.

Application scenario 2 is a scenario in which the channel state of each UE 100 is poor. As a scenario in which the channel state is inferior, a scenario in which each UE 100 is located near the cell edge of the eNB 200 can be cited.

As illustrated in FIG. 8, the eNB 200 generates a concatenated bit string by concatenating a plurality of bit strings composed of bit strings of each UE, and uses the same radio resource (RB # 1 to RB # 3) to generate a concatenated bit string. Is transmitted to each UE. Each UE 100 receives a radio signal including a concatenated bit string transmitted from the eNB 200 using RB # 1 to RB # 3, and extracts its own bit string from the concatenated bit string.

Here, the eNB 200 applies MCS corresponding to the channel state of each UE, that is, low MCS. In the example of FIG. 8, the eNB 200 assigns RB # 1 to RB # 3 to each UE and applies MCS0.

In application scenario 2, eNB 200 arranges a concatenated bit string in a plurality of resource blocks (RB # 1 to RB # 3) such that each of a plurality of bit strings composed of the bit strings of each UE is distributed in the frequency direction. The eNB 200 transmits the concatenated bit string using RB # 1 to RB # 3. Each UE 100 receives the concatenated bit string using RB # 1 to RB # 3.

As described above, the embodiment in the application scenario 2 can obtain the frequency diversity effect by arranging the bit strings of the UEs in the frequency direction. Therefore, it is possible to efficiently use radio resources and improve the reception quality of each UE. Similarly to the embodiment in the application scenario 1, by performing error correction coding on the concatenated bit string at a time, it is possible to increase the error correction capability and obtain a higher coding gain.

(2.3) Other Application Scenarios “Bit-wise multiplexing” is not limited to application scenario 1 or application scenario 2. “Bit-wise multiplexing” may be applied to scenarios other than the application scenario 1 or the application scenario 2. For example, it is possible to apply “Bit-wise multiplexing” to a scenario in which a short bit string of UE 100 # 2 performing small capacity communication is connected to a long bit string of UE 100 # 1 performing large capacity communication. .

(3) Bit-wise multiplexing according to the first embodiment
In the following, “Bit-wise multiplexing” (code block multiplexing) will be described. FIG. 9 is a diagram for explaining “Bit-wise multiplexing”. “Bit-wise multiplexing” is mainly performed in the LTE physical layer.

As illustrated in FIG. 9, the eNB 200 divides a transport block that is transmission data of each UE 100 (UE 100 # 1 to # 3) passed from an upper layer, and generates a bit string (code block) having a predetermined length. When the bit length of the transport block is a predetermined length, the transport block may be used as it is as a code block. Further, when the bit length of the transport block is less than the predetermined length, padding bits may be added so as to match the predetermined length. In the example of FIG. 9, the eNB 200 generates a code block # 1 from the transport block # 1 of the UE 100 # 1, generates a code block # 2 from the transport block # 2 of the UE 100 # 2, and transmits the code block # 2 of the UE 100 # 3. A code block # 3 is generated from the port block # 3.

Next, the eNB 200 performs “Codeblock connection”, which is a process of connecting the code blocks # 1 to # 3. Also, the eNB 200 adds one CRC (Cyclic Redundancy Check) to the concatenated code blocks # 1 to # 3 (concatenated code blocks). In the conventional method, a CRC is added to each code block. By adding one CRC to the concatenated code block, the CRC can be reduced as compared with the conventional method. However, a CRC may be added to each code block so that an error for each code block can be detected.

Next, the eNB 200 collectively performs error correction coding (for example, turbo coding) on the concatenated code block and the CRC. Further, the eNB 200 performs rate matching for coding rate adjustment. Thereafter, the eNB 200 performs radio interleaving processing, symbol mapping processing, and the like.

On the other hand, each UE 100 performs a process opposite to the process in the eNB 200. Each UE 100 receives a radio signal and performs symbol demapping processing, deinterleaving processing, and the like. Each UE 100 decodes the concatenated code block and the CRC.

Each UE 100 performs error detection of the concatenated code block by CRC. When a CRC error occurs, “HARQ NACK” may be transmitted to the eNB 200. When no CRC error occurs, that is, when decoding is correctly performed, “HARQ ACK” may be transmitted to the eNB 200.

If the decoding is correctly performed, each UE 100 extracts its own code block from the concatenated code blocks (code block # 1 to code block # 3). A method for identifying its own code block will be described later.

(4) Example of Operation Sequence According to First Embodiment Hereinafter, an operation sequence for appropriately controlling “Bit-wise multiplexing” will be described. FIG. 10 is a diagram illustrating an example of an operation sequence. In FIG. 10, this means that the process indicated by the broken line is arbitrary.

In step S101, the eNB 200 groups the UE 100. For example, in the case of the application scenario 1, the eNB 200 determines a group including a plurality of UEs 100 having a good channel state and transmitting / receiving a small amount of data. In the case of the application scenario 2, the eNB 200 determines a group including a plurality of UEs 100 having a poor channel state. At the time of grouping, the eNB 200 may determine the channel state of the UE 100 based on the CQI received from the UE 100 or a measurement report (Measurement Report). The eNB 200 determines a group including only the UE 100 having the “Bit-wise multiplexing” function based on the capability information (UE Capability Information) indicating that the UE 100 has the “Bit-wise multiplexing” function at the time of grouping. decide. “UE Capability Information” can be acquired from UE 100 or MME 300. Or in step S101, eNB200 may determine the group which consists of UE100 which performs large capacity communication, and UE100 which performs small capacity communication.

Note that, for example, an operation may be considered in which 10 UEs are set as one group and 4 UEs are selected from the 10 UEs and multiplexed and transmitted in actual transmission. Hereinafter, each UE set as one group is referred to as “each UE 100 belonging to the group”, and each UE multiplexed in actual transmission is referred to as “each code block multiplexed UE 100”, and these are particularly distinguished. When not, they are referred to as “plural UEs 100” or “each UE 100”.

In step S102, the eNB 200 notifies the following information to each UE 100 belonging to the group by RRC signaling.

・ Indication that code block multiplexing (bit-wise multiplexing) will be performed. The eNB 200 may also notify the HARQ process ID to be code block multiplexed.

∙ DCI reception group RNTI for code block multiplexing. The DCI reception group RNTI is a common identifier common to the UEs 100 belonging to the group.

・ Information to identify the code block.

After Steps S101 and S102, “Bit-wise multiplexing” is started.

In step S103, the eNB 200 transmits DCI on the PDCCH to each UE 100 that is code-block multiplexed. DCI includes information such as RB and MCS. The DCI may include NDI (New Data Indicator), “HARQ process ID”, and the like.

DCI is masked using DCI reception group RNTI. Specifically, the eNB 200 includes the CRC bits masked by the DCI reception group RNTI in the DCI. That is, eNB200 transmits the control signal for a concatenated code block to a plurality of UEs 100 in a batch using the common identifier.

In step S104, the eNB 200 transmits a concatenated code block on the PDSCH to each UE 100 that is code block multiplexed. The UE 100 receives the concatenated code block based on DCI.

In step S105, each UE 100 that is code-block multiplexed transmits “HARQ Ack / Nack” to the eNB 200. Details of HARQ applied to “Bit-wise multiplexing” will be described later.

In addition, when determining the group which consists of UE100 which performs high capacity | capacitance communication, and UE100 which performs small capacity | capacitance communication, eNB200 may notify each UE100 by the RRC signaling and / or DCI about the code block length.

Also, in this operation sequence, an example in which DCI common to each UE 100 that is code-block multiplexed (and DCI reception RNTI for masking thereof) has been described. However, a pattern in which DCI is individually transmitted to each UE 100 that is code-block multiplexed is also possible. In this pattern, the eNB 200 may individually assign an RNTI dedicated to “Bit-wise Multiplexing” for each UE, or may use a normal unicast C-RNTI (Cell-Radio Network Temporary Identifier) as it is. . Also, it is desirable that a dedicated DCI format including a bit field for “Bit-wise Multiplexing” is defined, and distinction from normal unicast can be performed by this DCI format. Alternatively, the distinction from the normal unicast can be made by the HARQ process ID (set to be used for “Bit-wise Multiplexing”).

(5) Code Block Identification Method According to First Embodiment Hereinafter, a code block identification method in “Bit-wise multiplexing” will be described. Specifically, a method for the UE 100 to identify a confident code block included in the concatenated code block will be described.

(5.1) Pattern 1
In Pattern 1, the eNB 200 notifies each UE 100 (target UE) that is code block multiplexed, of an index indicating the position of the code block of the target UE in the concatenated code block. The index is, for example, an index indicating the number from the top in the concatenated code block. UE100 receives the said index from eNB200. The eNB 200 notifies the number of UEs that are code block multiplexed together. The notification of the index and the notification of the number of UEs that are code-block multiplexed are performed by RRC signaling (step S102 in FIG. 10). Alternatively, the number of UEs that are code-block multiplexed may be a system-defined value, and notification to the UE 100 may be omitted.

Each UE 100 that is code-block multiplexed uses the index notified from the eNB 200 to identify its own code block from among the concatenated code blocks received from the eNB 200 and extract its own code block.

(5.2) Pattern 2
In pattern 2, the eNB 200 notifies each UE 100 belonging to the group of “dedicated RNTI for data reception” at the time of code block multiplexing. “Dedicated RNTI for data reception” is a dedicated identifier that does not overlap among UEs belonging to a group. The bit length of “dedicated RNTI for data reception” may be shorter than the bit length of normal RNTI (16 bits). The notification of “dedicated RNTI for data reception” is performed by RRC signaling (step S102 in FIG. 10).

The eNB 200 adds the corresponding “dedicated RNTI for data reception” to each code block in the concatenated code block, and transmits the concatenated code block. For example, the eNB 200 adds “dedicated RNTI for data reception” of the UE 100 # 1 to the head or the end of the code block # 1 of the UE 100 # 1.

Each UE 100 that is code-block multiplexed uses the “dedicated RNTI for data reception” notified from the eNB 200 to identify its own code block from among the concatenated code blocks received from the eNB 200, and to identify its own code block. Extract.

(6) Common RNTI
The common RNTI in “Bit-wise multiplexing” will be described below.

The first common RNTI is the above-described DCI reception group RNTI. The DCI reception group RNTI is a common identifier common to the UEs 100 belonging to the group. The eNB 200 uses the DCI reception group RNTI to collectively transmit DCI (PDCCH) for the concatenated code block to each UE 100 that is code block multiplexed. The UE 100 receives DCI (PDCCH) for the concatenated code block using the DCI reception group RNTI.

The second common RNTI is a data reception group RNTI applied to the CRC (see FIG. 9) added to the concatenated code block. The data reception group RNTI may be the same as the DCI reception group RNTI. When the DCI reception group RNTI and the data reception group RNTI are different, the eNB 200 notifies the data reception group RNTI by RRC signaling (step S102 in FIG. 10). The eNB 200 masks the CRC added to the concatenated code block using the data reception group RNTI. The UE 100 demasks the CRC using the data reception group RNTI.

Alternatively, the data group RNTI may be a system-defined value, and notification to the UE 100 may be omitted.

Alternatively, the CRC may be transmitted as it is without applying the RNTI for data reception. In this case, the RNTI for data reception is not necessary.

(7) Code Block Length Table Hereinafter, the code block length table in “Bit-wise multiplexing” will be described.

Generally, the bit length that can be transmitted is determined by the number of resource blocks (RB) used for data transmission and the MCS used for the transmission. Each of the eNB 200 and the UE 100 holds information indicating a bit length (TBS: Transport Block Size) that can be transmitted for each combination of the number of RBs and the MCS. Specifically, each of the eNB 200 and the UE 100 holds a table in which the number of RBs, the MCS, and the transmittable bit length are associated with each other.

In the case of “Bit-wise multiplexing”, the bit length that can be transmitted to each UE 100 that is code block multiplexed (that is, the bit length of the code block of each UE 100) differs according to the number of UEs that are code block multiplexed. Therefore, in the first embodiment, each of the eNB 200 and the UE 100 holds a table for “Bit-wise multiplexing”. Specifically, the eNB 200 includes information indicating a bit length (code block length) that can be transmitted to each UE for each combination of the number of RBs used for transmission, the MCS used for transmission, and the number of UEs to be multiplexed. Hold. The UE 100 holds information indicating a bit length (code block length) that can be received from the eNB 200 for each combination of the number of RBs used for reception, the MCS used for reception, and the number of UEs to be multiplexed.

(8) HARQ ACK / NACK resource In the following, the HARQ ACK / NACK resource in “Bit-wise multiplexing” will be described.

(8.1) Pattern 1
In pattern 1, HARQ NACK is applied to “Bit-wise multiplexing” without applying HARQ ACK. The eNB 200 allocates a common radio resource to each UE 100 (or each UE 100 belonging to a group) that is code-block multiplexed. Each UE 100 that is code-block multiplexed transmits HARQ NACK to the eNB 200 using the common radio resource. The eNB 200 receives the HARQ NACK using the common radio resource.

As described above, by using only HARQ NACK as delivery confirmation information for HARQ, uplink radio resources (for example, PUCCH resources) associated with transmission of HARQ ACK can be saved.

Further, the common radio resource includes a resource element common to each UE 100 (or each UE 100 belonging to a group) that is code-block multiplexed, and a common signal sequence (base sequence, cyclic shift). By using common radio resources, uplink radio resources (for example, PUCCH resources) associated with HARQ NACK transmission can also be saved.

However, by applying the HARQ NACK by such a common resource, the HARQ NACK of each UE 100 that is code block multiplexed is combined, and the eNB 200 cannot identify the source UE of the HARQ NACK. However, it is not necessary to identify which UE 100 is the HARQ NACK by performing retransmission for all the UEs 100 that are code-block multiplexed.

FIG. 11 is a diagram illustrating an example of an operation sequence in pattern 1 of the HARQ ACK / NACK resource.

As illustrated in FIG. 11, in step S301, the eNB 200 transmits setting information related to the common resource for HARQ NACK transmission to the UE 100 # 1 and the UE 100 # 2. The setting information related to the common resource for HARQ NACK transmission may be broadcast from the eNB 200 by system information (SIB), or may be unicast from the eNB 200 by individual RRC signaling. Each UE 100 receives and stores setting information.

In step S302, the eNB 200 starts transmission of the concatenated code block by “Bit-wise multiplexing”.

In step S303, the UE 100 # 1 and the UE 100 # 2 try to decode the received concatenated code block.

In step S304, the UE 100 # 1 and the UE 100 # 2 confirm whether or not the decoding of the concatenated code block is successful. Here, it is assumed that both UE 100 # 1 and UE 100 # 2 fail to decode.

In step S305, the UE 100 # 1 and the UE 100 # 2 transmit the HARQ NACK to the eNB 200 using the common resource for HARQ NACK transmission. These HARQ NACKs are received by the eNB 200 in a combined state.

In step S306, the eNB 200 transmits retransmission data (concatenated code block) to the UE 100 # 1 and the UE 100 # 2 in response to receiving the HARQ NACK.

(8.2) Pattern 2
In pattern 2, the eNB 200 performs dedicated radio that does not overlap between each UE 100 (or each UE 100 belonging to a group) that is code-block multiplexed with respect to each UE 100 (or each UE 100 that belongs to a group) that is code-block multiplexed. Allocate resources. UE100 transmits HARQ ACK / NACK to eNB200 using a dedicated radio | wireless resource. The eNB 200 receives HARQ ACK / NACK using dedicated radio resources.

For example, the dedicated radio resource is a PUCCH resource that does not overlap between each UE 100 (or each UE 100 belonging to a group) that is code-block multiplexed. N ⁽¹⁾ _PUCCH can be used as such a PUSCH resource. UE100 determines the PUCCH resource for transmission of HARQ ACK according to N ⁽¹⁾ _PUCCH which is a PUCCH parameter set by RRC signaling from eNB200. For example, in the case of FDD, the UE 100 determines a PUCCH resource for HARQ ACK transmission according to the following equation (1).

However, “n _CCE ” is the number of the first CCE (Control Channel Element) used for transmission of the corresponding downlink assignment (DCI).

According to Pattern 2, the eNB 200 can identify the source UE of the HARQ ACK based on N ⁽¹⁾ _PUCCH applied to the HARQ ACK.

Alternatively, instead of using such a dedicated radio resource, a common radio resource may be used. The eNB 200 spatially separates HARQ Ack / Nack using the same method as uplink MU-MIMO.

(9) Independent HARQ
In the following, independent HARQ in “Bit-wise multiplexing” will be described. However, independent HARQ does not have to be applied to pattern 1 of the HARQ ACK / NACK resource. In “Bit-wise multiplexing”, independent HARQ can be applied to each UE 100 that is code-block multiplexed.

When independent HARQ is applied to “Bit-wise multiplexing”, each UE 100 multiplexed in code block is a portion corresponding to its own code block in stored data (stored concatenated code block) at the time of previous reception failure. Only for HARQ synthesis.

When independent HARQ is applied to “Bit-wise multiplexing”, an independent NDI is required for each UE 100 that is code-block multiplexed. Normally, NDI is included in DCI, but when DCI common to each UE 100 that is code-block multiplexed is used, it is difficult to include NDI independent of each UE 100 in DCI.

Therefore, the eNB 200 adds an indicator (NDI) indicating whether the transmission is initial transmission or retransmission to each of the plurality of code blocks in the concatenated code block. Using the indicator (NDI), the UE 100 determines whether the code block of the own UE 100 extracted from the concatenated code block is initial transmission or retransmission. Specifically, the UE 100 determines whether the code block is an initial transmission or a retransmission based on the NDI included in the code block of the own UE 100 extracted from the concatenated code block.

[Modification of First Embodiment]
In the first embodiment described above, an example in which the radio communication device that performs multiplex communication with a plurality of user terminals is the eNB 200 has been described. However, the wireless communication device that performs multiplex communication with a plurality of user terminals may be a relay node or a D2D (Device to Device) terminal. The relay node is a wireless communication device that relays communication between the eNB 200 and the UE 100. The D2D terminal is a radio communication device that can perform direct radio communication with a plurality of UEs 100.

[Second Embodiment]
In the following, the difference between the second embodiment and the first embodiment will be mainly described.

(1) Application scenario according to the second embodiment Hereinafter, an application scenario according to the second embodiment will be described. FIG. 12 is a diagram for explaining an application scenario according to the second embodiment.

As shown in FIG. 12, a plurality of UEs 100 (UE100 # 1 to UE100 # 5) perform UL transmission to the eNB 200. In a general LTE system, the UE 100 transmits data to the eNB 200 using the UL resource explicitly assigned from the eNB 200. Specifically, the eNB 200 allocates an orthogonal UL resource to each UE 100, and transmits a UL grant indicating the UL allocation to the UE 100. The UE 100 performs data transmission by PUSCH in a UL subframe after a predetermined subframe (for example, 4 subframes) from the timing at which UL grant is received. Thus, UL transmission in a general LTE system is performed using synchronous and orthogonal resources.

On the other hand, technologies for new scenarios such as Massive MTC (Machine Type Communication) and URLLC (Ultra-Reliable Low-Latency Communication) are being studied as technologies for the fifth generation (5G). In such a new scenario, it is assumed that UL transmission is performed on demand using an asynchronous and non-orthogonal resource without an explicit assignment from the eNB 200. For example, the UE 100 transmits UL data using non-orthogonal resources as soon as UL data is generated. When a plurality of UEs 100 transmit UL data using the same UL resource, the UL data is separated by signal processing on the eNB 200 side.

In such on-demand asynchronous UL transmission, it is not realistic to prepare HARQ ACK / NACK orthogonal DL resources in advance for all UEs 100 that may transmit UL data. This is because, in the new scenario described above, the frequency with which UL data from each UE 100 is actually transmitted may be low, and the DL resource utilization efficiency is significantly deteriorated. On the other hand, when the eNB 200 transmits HARQ ACK / NACK using non-orthogonal DL resources, the processing load for performing signal separation on the UE 100 side increases. Moreover, since UE100 for MTC has low processing performance, it is difficult to perform advanced signal processing.

The second embodiment makes it possible to solve problems in a new scenario by applying “Bit-wise multiplexing” to HARQ ACK / NACK transmission from the eNB 200 to the UE 100.

(2) Bit-wise multiplexing according to the second embodiment
FIG. 13 is a diagram for explaining “Bit-wise multiplexing” according to the second embodiment. Here, an example in which the eNB 200 transmits HARQ ACK to the UE 100 # 1 to the UE 100 # 3 will be described. Further, differences from the first embodiment will be mainly described.

As illustrated in FIG. 13, the eNB 200 generates a bit string (code block) including an identifier of each UE 100 that is a transmission destination of the HARQ ACK. In the example of FIG. 13, the eNB 200 includes a code block including a UE identifier # 1 that is an identifier of the UE 100 # 1, a code block including a UE identifier # 2 that is an identifier of the UE 100 # 2, and a UE that is an identifier of the UE 100 # 3. A code block including the identifier # 3 is generated.

Next, the eNB 200 concatenates three code blocks each including a UE identifier by “Codeblock connection”. Also, the eNB 200 adds one CRC to the concatenated code block.

Each UE 100 performs error detection of the concatenated code block by CRC. When a CRC error does not occur, that is, when decoding is correctly performed, each UE 100 extracts a code block including its own UE identifier from the concatenated code block. The UE 100 that has extracted the code block including its own UE identifier recognizes that it has received the HARQ ACK from the eNB 200.

Note that the UE identifier may be any identifier as long as it is information that can identify the UE 100. Next, specific examples of UE identifiers will be given. However, it is not always necessary to use the entire UE identifier, and only a part of each UE identifier may be used to reduce the bit length. For example, the UE identifier may be an identifier that the eNB 200 assigns to the UE 100 as in C-RNTI, or may be a fixed identifier such as IMSI (International Mobile Subscriber Identity). Alternatively, a temporary or permanent identifier assigned by the eNB 200 or the EPC 20 separately from the C-RNTI, or an identifier unique to a product or contract may be defined separately from the IMSI. Alternatively, a value randomly selected by the UE 100 may be included in the UL data as a UE identifier and transmitted to the eNB 200, and the eNB 200 may use the UE identifier for HARQ ACK transmission to the UE 100. In this case, since UE identifiers may collide between a plurality of UEs 100, the eNB 200 may detect that the plurality of UEs 100 use the same UE identifier. The eNB 200 may instruct a plurality of UEs 100 that use the same UE identifier to change the UE identifier.

In addition, although an example has been described in which the eNB 200 transmits HARQ ACK to a plurality of UEs 100 (UE100 # 1 to UE100 # 3), HARQ NACK may be transmitted instead of HARQ ACK. Moreover, eNB200 may transmit HARQ NACK with respect to UE100 which wants to transmit HARQ NACK while transmitting HARQ ACK with respect to UE100 which wants to transmit HARQ ACK among several UE100. Note that there are three reception patterns in the eNB 200: “successful reception”, “detection of reception failure / transmission detected”, and “detection of reception failure / transmission not detected”. HARQ ACK is transmitted in the first pattern and HARQ NACK is transmitted in the second pattern, but neither ACK nor NACK may be transmitted in the third pattern.

In the second embodiment, the eNB 200 may add an indicator of whether the UE identifier included in the code block indicates HARQ ACK or HARQ NACK to the code block. For example, in FIG. 13, it is assumed that the eNB 200 transmits HARQ ACK to the UE 100 # 1, and transmits HARQ NACK to the UE 100 # 2 and the UE 100 # 3. In this case, the eNB 200 generates a code block including the UE identifier # 1 and the ACK indicator, a code block including the UE identifier # 2 and the NACK indicator, and a code block including the UE identifier # 3 and the NACK indicator. Then, the eNB 200 transmits the concatenated code block. When each UE 100 can correctly decode the concatenated code block, the UE 100 extracts a code block including its own UE identifier from the concatenated code block. Each UE 100 determines whether ACK is transmitted or NACK is transmitted according to the indicator included in the extracted code block. Alternatively, only one of the ACK indicator and the NACK indicator may be used. For example, when only the NACK indicator is used, the eNB 200 adds the NACK indicator to the identifier of the UE 100 that is the transmission destination of the HARQ NACK, but does not add the ACK indicator to the identifier of the UE 100 that is the transmission destination of the HARQ ACK. Each UE 100 extracts a code block including its own UE identifier, recognizes that a HARQ NACK has been transmitted if the NACK indicator is included in the code block, and HARQ if the NACK indicator is not included in the code block. Recognize that ACK has been sent. In addition to the method of explicitly including the ACK / NACK indicator in the message (concatenated code block), ACK / NACK may be implicitly identifiable using the concatenated code block. For example, the ACK resource and the NACK resource may be used separately as resources used for concatenated code block transmission, and the method may be identified by the resource. Alternatively, the RNTI may be identified by using the ACK RNTI and the NACK RNTI separately as the RNTI used for CRC scrambling added to the concatenated code block.

Alternatively, the eNB 200 may transmit an indicator of whether the UE identifier included in the code block indicates HARQ ACK or HARQ NACK by DCI. Moreover, you may provide the indicator which identifies HARQ ACK / NACK for every code block in a connection code block. For example, in FIG. 13, it is assumed that HARQ ACK is transmitted to UE 100 # 1, and HARQ NACK is transmitted to UE 100 # 2 and UE 100 # 3. In this case, the eNB 200 includes a bit string such as “100” in the DCI. In this bit string, the bit position corresponds to the position of the code block, “1” indicates HARQ ACK, and “0” indicates HARQ NACK. That is, the first code block is HARQ ACK, and the second and third code blocks are HARQ NACK. Further, the eNB 200 generates a code block including the UE identifier # 1, a code block including the UE identifier # 2, and a code block including the UE identifier # 3, concatenates the code blocks, and transmits the DCI and the concatenated code block. To do. When each UE 100 can correctly decode the concatenated code block, the UE 100 extracts a code block including its own UE identifier from the concatenated code block. Also, each UE 100 identifies whether ACK is transmitted or NACK is transmitted based on an indicator included in DCI. In addition to the method of explicitly including the ACK / NACK indicator in DCI, ACK / NACK may be implicitly identifiable using DCI. Specifically, the RNTI may be identified by using the ACK RNTI and the NACK RNTI separately as the RNTI used for CRC scrambling. Alternatively, a method may be used in which ACK resources and NACK resources are selectively used as resources (for example, search spaces and resource blocks) used for DCI transmission, and are identified by resources.

Alternatively, the eNB 200 includes a concatenated code block composed only of a UE identifier (for example, UE identifier # 1) that transmits ACK and a concatenated code composed only of a UE identifier (for example, UE identifiers # 2 and 3) that transmits NACK. Each block may be generated and transmitted. In this case, an identifier indicating whether the concatenated code block indicates ACK or NACK may be included in DCI. Alternatively, the format and contents of DCI (for example, including a retransmission parameter in the case of NACK) may be different for ACK and NACK. Alternatively, an identifier of ACK or NACK may be included in the concatenated code block (only ACK is added, only NACK is added, or both are added).

Also, when assuming on-demand asynchronous UL transmission, the number of UEs 100 to which HARQ ACK / NACK is transmitted by a concatenated code block may be variable (scalable) according to the number of UL transmissions at that time. preferable. In the second embodiment, a plurality of UEs 100 in which HARQ ACK / NACK is transmitted by one concatenated code block are referred to as “ACK / NACK transmission group”. The eNB 200 adds Length information indicating the number of UEs in the ACK / NACK transmission group and / or the bit length of the connection code block to the connection code block to be transmitted to the ACK / NACK transmission group. Send. Or eNB200 may transmit Length information by DCI. Each UE in the ACK / NACK transmission group recognizes the number of UEs in the ACK / NACK transmission group and / or the bit length of the concatenated code block based on the Length information.

In the second embodiment, the eNB 200 groups a plurality of UEs 100 that have transmitted data to the own eNB 200 within a predetermined period (t1 to t2, see FIG. 14) as an ACK / NACK transmission group. The eNB 200 transmits a concatenated code block addressed to the ACK / NACK transmission group at a timing (t3) after the elapse of a predetermined period (t1 to t2). When the number of UEs 100 that have transmitted data to the own eNB 200 is large within a predetermined period (t1 to t2), the eNB 200 may set a plurality of ACK / NACK transmission groups.

For example, the eNB 200 performs grouping according to the channel state as in the first embodiment. Here, NB200 may judge a channel state based on reception quality of UL transmission from UE100. Alternatively, when channel state information is included in the UL transmission from the UE 100, the channel state may be determined based on the channel state information.

Alternatively, the eNB 200 may perform grouping based on the UE identifier, or may perform grouping based on resources used for UL transmission. The eNB 200 may limit the UL transmission opportunity for each UE 100 and use it for grouping. For example, the eNB 200 notifies the information indicating the range of the UE identifier, the UL transmission opportunity corresponding thereto, and the UL resource by broadcast signaling. The UE 100 performs UL transmission at a UL transmission opportunity corresponding to its own UE identifier. The eNB 200 performs grouping based on the UE identifier and / or UL resource.

In the second embodiment, the eNB 200 may adjust the MCS and / or DL resource amount applied to the transmission of the concatenated code block according to the number of UEs in the ACK / NACK transmission group. For example, as the number of UEs in the ACK / NACK transmission group increases, the eNB 200 may increase the MCS, increase the frequency resource (the number of allocated RBs), or allocate time resources by a method such as TTI bundling. May increase.

(3) An example of an operation sequence according to the second embodiment Hereinafter, an example of an operation sequence according to the second embodiment will be described, focusing on differences from the first embodiment. FIG. 14 is a diagram illustrating an example of an operation sequence according to the second embodiment. In FIG. 14, the process indicated by the broken line means that it is arbitrary.

As shown in FIG. 14, in step S201, the eNB 200 may transmit information regarding a predetermined period (t1 to t2) and information regarding ACK / NACK transmission timing (t3) to the UE 100. The eNB 200 may notify the UE 100 of each of the timings t1, t2, and t3. Or you may notify UE100 of one timing (for example, t1) and the relative time of the other timing (for example, t2, t3) on the basis of the said one timing. The eNB 200 may notify the UE 100 of a plurality of candidate timings as the ACK / NACK transmission timing (t3). Moreover, eNB200 may transmit the information regarding UL transmission resource to UE100. For example, the eNB 200 may notify the UE 100 of at least one resource pool including time / frequency resources that can be used for UL transmission. Furthermore, the eNB 200 may notify the UE 100 of the availability conditions for each resource pool. The usable condition may be the above-described UE identifier range or a radio quality threshold value. Step S201 may be performed by broadcast signaling or may be performed by UE dedicated (dedicated) signaling. Instead of broadcast signaling, group cast (or multicast) signaling may be used.

In step S202, the UE 100 transmits UL data to the eNB 200. The UE 100 may perform repeated transmission (Repetition) of UL data.

In step S203, the eNB 200 groups a plurality of UEs 100 that have transmitted data to the self eNB 200 within a predetermined period (t1 to t2) as an ACK / NACK transmission group.

In step S204, the eNB 200 transmits the DCI (PDCCH) and the concatenated code block (PDSCH) addressed to the ACK / NACK transmission group at a timing (t3) after the elapse of a predetermined period (t1 to t2). When the UE 100 performs UL data repetitive transmission (Repetition), the UE 100 may stop repetitive transmission in response to reception of the concatenated code block. Note that the eNB 200 may perform repeated transmission (Repetition) of the concatenated code block.

In step S205, the eNB 200 may transmit information (stop bit) indicating that transmission of the ACK and / or NACK concatenated code block for the UL transmission in a predetermined period is completed to the UE 100 by broadcast signaling, for example. When a plurality of candidate timings are notified to the UE 100 as the ACK / NACK transmission timing (t3), the UE 100 stops the connection code block reception attempt in response to the reception of the information (stop bit).

[Other Embodiments]
The operation according to the first embodiment described above may be applied to the second embodiment as appropriate. Moreover, 1st Embodiment and 2nd Embodiment may be implemented separately independently, and may implement combining both embodiment. When implementing both embodiments in combination, the eNB 200 transmits a transmission content indicator as to whether the transmission by “Bit-wise multiplexing” is data transmission (first embodiment) or ACK / NACK transmission (second embodiment). May be transmitted to the UE 100. For example, the transmission content indicator may be transmitted by being added to the concatenated code block, or may be transmitted by DCI.

In the above-described second embodiment, an example in which “Bit-wise multiplexing” is applied to HARQ ACK / NACK transmission has been described. Here, HARQ is a function of the MAC layer. However, “Bit-wise multiplexing” may be applied to ACK / NACK transmission different from HARQ. For example, “Bit-wise multiplexing” can be applied to ARQ ACK / NACK transmission in the RLC layer.

In the second embodiment described above, a relay UE may be interposed between the eNB 200 and the plurality of UEs 100. The relay UE has a function of relaying communication between the eNB 200 and the plurality of UEs 100. When the relay UE can decipher the concatenated code block, the relay UE deciphers the concatenated code block received from the eNB 200, divides the code block for each UE 100, and transmits information based on the code block obtained by the division to the UE 100. You may send it. Specifically, the relay UE manages each identifier of the plurality of UEs 100. Based on the identifier in the code block, the relay UE identifies the UE 100 that is the transmission destination of the code block. The relay UE may relay the code block to the identified UE 100, or may transmit the code block to the UE 100 in the form of ACK / NACK.

In the above-described embodiment, the LTE system is exemplified as the wireless communication system. However, the present invention is not limited to LTE systems. The present invention may be applied to a system other than the LTE system.

The entire contents of Japanese Patent Application No. 2015-091061 (filed on April 28, 2015) and Japanese Patent Application No. 2016-021182 (filed on February 5, 2016) are incorporated herein by reference. Yes.

The present invention is useful in the communication field.

Claims

A control unit that generates a concatenated bit string by concatenating a plurality of bit strings composed of respective bit strings of a plurality of user terminals; and
Using the same radio resource, a transmitter that transmits a radio signal including the concatenated bit string to the plurality of user terminals;
A wireless communication device comprising:
The number of resource blocks used for transmission of the concatenated bit string is less than the total number of the plurality of user terminals,
The wireless communication apparatus according to claim 1.
The control unit arranges the concatenated bit string in one resource block,
The transmission unit transmits a radio signal including the concatenated bit string using the one resource block.
The wireless communication apparatus according to claim 2.
The control unit arranges the concatenated bit string in a plurality of resource blocks so that each of the plurality of bit strings is distributed in the frequency direction,
The transmitter uses the plurality of resource blocks to transmit a radio signal including the concatenated bit string.
The wireless communication apparatus according to claim 1.
The controller is
Add one CRC to the concatenated bit string,
Performing error correction coding on the concatenated bit string and the CRC at once;
The wireless communication apparatus according to claim 1.
The control unit notifies an index indicating a position of a bit string of the target user terminal in the concatenated bit string for each target user terminal included in the plurality of user terminals.
The wireless communication apparatus according to claim 1.
The controller is
A dedicated identifier that is not duplicated between the plurality of user terminals is assigned to each of the plurality of user terminals,
A corresponding dedicated identifier is added to each of the plurality of bit strings.
The wireless communication apparatus according to claim 1.
The control unit assigns a common identifier common to the plurality of user terminals to each of the plurality of user terminals,
The transmission unit transmits a control signal for the concatenated bit string to the plurality of user terminals using the common identifier.
The wireless communication apparatus according to claim 1.
The controller is
A common identifier common to the plurality of user terminals is assigned to each of the plurality of user terminals,
Masking the CRC using the common identifier;
The wireless communication apparatus according to claim 5.
The control unit holds information indicating the bit length that can be transmitted to each user terminal for each combination of the number of resource blocks used for transmission, the modulation and coding scheme used for transmission, and the number of user terminals to be multiplexed. To
The wireless communication apparatus according to claim 1.
HARQ NACK is applied to the communication between the wireless communication apparatus and the plurality of user terminals without applying HARQ ACK,
The control unit performs a process of receiving the HARQ NACK from the plurality of user terminals using a common radio resource common to the plurality of user terminals.
The wireless communication apparatus according to claim 1.
The control unit performs processing for receiving HARQ ACK / NACK from the plurality of user terminals by using dedicated radio resources that do not overlap between the plurality of user terminals.
The wireless communication apparatus according to claim 1.
Independent communication between each of the plurality of user terminals is applied to communication between the wireless communication apparatus and the plurality of user terminals,
The control unit adds an indicator indicating whether the transmission is initial transmission or retransmission to each of the plurality of bit strings.
The wireless communication apparatus according to claim 1.
The control unit groups the plurality of user terminals as ACK / NACK transmission destinations,
The bit string includes an identifier of a user terminal to which the ACK / NACK is transmitted,
The wireless communication apparatus according to claim 1.
The transmitting unit transmits an indicator as to whether the identifier indicates an identifier of a user terminal that transmits ACK or an identifier of a user terminal that transmits NACK;
The wireless communication apparatus according to claim 14.
The transmitter transmits information indicating a number of the plurality of user terminals and / or a bit length of the concatenated bit string;
The wireless communication apparatus according to claim 14.
The control unit groups the plurality of user terminals that have transmitted data to the wireless communication device within a predetermined period as transmission destinations of the ACK / NACK,
The transmitter transmits the concatenated bit string at a timing after the predetermined period has elapsed.
The wireless communication apparatus according to claim 14.
A user terminal included in a plurality of user terminals,
A reception unit that receives a radio signal that is transmitted from a radio communication device using the same radio resource and that includes a concatenated bit string that includes each bit string of the plurality of user terminals;
A control unit for extracting a bit string of the user terminal from the concatenated bit string;
A user terminal comprising:
One CRC is added to the concatenated bit string,
The controller is
Decoding the concatenated bit string and the CRC;
Error detection of the concatenated bit string is performed by the CRC.
The user terminal according to claim 18.
The receiving unit receives an index indicating a position of a bit string of the user terminal in the concatenated bit string from the wireless communication device;
The control unit uses the index to extract a bit string of the user terminal from the concatenated bit string.
The user terminal according to claim 18.
The own user terminal is assigned a dedicated identifier that is not duplicated among the plurality of user terminals,
A corresponding dedicated identifier is added to each of the plurality of bit strings,
The control unit uses the dedicated identifier to extract a bit string of the user terminal from the concatenated bit string.
The user terminal according to claim 18.
The common user terminal is assigned a common identifier common to the plurality of user terminals,
The CRC is masked using the common identifier;
The controller demasks the CRC using the common identifier;
The user terminal according to claim 19.
Independent communication between each of the plurality of user terminals is applied to communication between the wireless communication apparatus and the plurality of user terminals,
Each of the plurality of bit strings is attached with an indicator indicating whether it is initial transmission or retransmission,
The control unit uses the indicator to determine whether the bit sequence of the user terminal extracted from the concatenated bit sequence is initial transmission or retransmission.
The user terminal according to claim 18.
The plurality of user terminals are transmission destinations of ACK / NACK transmitted by the wireless communication device,
The bit string includes an identifier of a user terminal to which the ACK / NACK is transmitted,
The control unit recognizes that the ACK / NACK addressed to the own user terminal is received when a bit string including an identifier of the own user terminal is included in the concatenated bit string.
The user terminal according to claim 18.
The receiving unit receives an indicator from the wireless communication apparatus whether the identifier included in the concatenated bit string indicates an identifier of a user terminal that transmits ACK or an identifier of a user terminal that transmits NACK,
The control unit identifies, based on the indicator, whether ACK or NACK is received when a bit string including an identifier of the user terminal is included in the concatenated bit string.
The user terminal according to claim 24.
The receiving unit receives information indicating the number of the plurality of user terminals and / or the bit length of the concatenated bit string from the wireless communication device,
The control unit recognizes the number of the plurality of user terminals and / or the bit length of the concatenated bit string based on the information.
The user terminal according to claim 24.