WO2018235263A1 - Wireless communication system enabling non-orthogonal multiple access, wireless communication base station, and wireless terminal - Google Patents

Wireless communication system enabling non-orthogonal multiple access, wireless communication base station, and wireless terminal Download PDF

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WO2018235263A1
WO2018235263A1 PCT/JP2017/023203 JP2017023203W WO2018235263A1 WO 2018235263 A1 WO2018235263 A1 WO 2018235263A1 JP 2017023203 W JP2017023203 W JP 2017023203W WO 2018235263 A1 WO2018235263 A1 WO 2018235263A1
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control information
downlink
downlink control
wireless terminal
wireless
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PCT/JP2017/023203
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French (fr)
Japanese (ja)
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督 矢部
義博 河▲崎▼
村田 博康
孝斗 江崎
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富士通株式会社
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation

Abstract

The radio base station selects a first radio terminal and a second radio terminal for multiplexing the downlink data signal on the same downlink radio resource by the non-orthogonal multiple access method among the plurality of radio terminals, and In the first downlink control information which is downlink control information related to the first downlink data signal addressed to, the second downlink control information related to downlink control information related to the second downlink data signal addressed to the second radio terminal is arranged Storing reference information indicating the position of the radio resource, and the downlink signal in which the first downlink control information, the second downlink control information, the first downlink data signal, and the second downlink data signal are arranged, Transmit using a wireless communication circuit.

Description

Wireless communication system capable of non-orthogonal multiple access system, wireless base station, wireless terminal

The present invention relates to a wireless communication system, a wireless base station, and a wireless terminal capable of non-orthogonal multiple access.

In recent years, in wireless communication systems (also called mobile communication systems) such as mobile phone systems (cellular systems), in order to further increase the speed and capacity of wireless communication, there is a debate about next-generation wireless communication technologies. It has been done. For example, in 3GPP (3rd Generation Partnership Project), which is a standardization organization, specifications of a communication standard called Long Term Evolution (LTE) and a communication standard called LTE-A (LTE-Advanced) based on LTE wireless communication technology. It has already been formulated, and studies are ongoing to expand its functions. For example, discussions are being made on standardization of the fifth generation mobile communication system (also called 5G system) that realizes the contents of the operation scenario and the technical requirements presented by ITU-R (International Telecommunication Union Radio communications sector). .

In the fifth generation mobile communication system, in order to improve frequency utilization efficiency (also referred to as band utilization efficiency), it is considered to adopt non-orthogonal multiple access (NOMA) as a multiple access scheme. ing. In non-orthogonal multiple access schemes, different radio terminals are allocated the same radio resources in time and frequency. At this time, the radio base station allocates a large amount of transmission power to a radio terminal having a large propagation loss (also referred to as transmission loss or path loss), and allocates a small amount of transmission power to a radio terminal having a small propagation loss. As a result, radio resources are multiplexed on the power axis, and the frequency utilization efficiency is further improved. In other words, signals carried to each of a plurality of users are multiplexed and transmitted on radio resources of the same time and the same frequency.

When multiplexing a signal carried to each of a plurality of users on the power axis to a downlink signal, the radio terminal demodulates and demodulates a signal (also referred to as a downlink data signal or data signal) directed to another terminal. The interference component is removed from the downlink signal based on the downlink data signal addressed to the other terminal (also referred to as interference cancellation, interference cancellation, interference suppression, interference cancellation), and then the downlink data signal addressed to the own terminal is demodulated. . Therefore, it is desirable that a wireless terminal in a non-orthogonal multiple access scheme acquire information (also referred to as information on interference components) for demodulating a downlink data signal addressed to another terminal using some method. In other words, it is desirable that the wireless base station of the non-orthogonal multiple access scheme notify the wireless terminal of the information on the interference component using any method.

In the prior art, when the radio base station transmits downlink control information (DCI: Downlink Control Information) to the first radio terminal, information for demodulating a downlink data signal addressed to the second radio terminal It has been proposed to duplicate and transmit the downlink control information for the second wireless terminal and the downlink control information for the first wireless terminal (for example, Patent Document 1 and Patent Document 2).

JP, 2016-146554, A US Patent Application Publication No. 2015/0312074

3GPP TS 36.211 V14.2.0 (2017-03) 3GPP TS 36.212 V14.2.0 (2017-03) 3GPP TS 36.213 V14.2.0 (2017-03) 3GPP TS 36.300 V14.2.0 (2017-03) 3GPP TS 36.321 V14.2.0 (2017-03) 3GPP TS 36.322 V14.0.0 (2017-03) 3GPP TS 36.323 V14.2.0 (2017-03) 3GPP TS 36.331 V14.2.0 (2017-03) 3GPP TS 36.413 V14.2.0 (2017-03) 3GPP TS 36.423 V14.2.0 (2017-03) 3GPP TS 36.425 V14.0.0 (2017-03) 3GPP TR 38.801 V14.0.0 (2017-03) 3GPP TR 38.802 V14.0.0 (2017-03) 3GPP TR 38.803 V14.0.0 (2017-03) 3GPP TR 38.804 V14.0.0 (2017-03) 3GPP TR 38.900 V14.2.0 (2016-12) 3GPP TR 38.912 V14.0.0 (2017-03) 3GPP TR 38.913 V14.0.0 (2017-03) Y. Saito, Y. Kishiyama, A. Benjebbour, T. Nakamura, A. Li, and K. Higuchi, "Non-orthogonal multiple access (NOMA) for future radio access," Proc. IEEE VTC2013-Spring, pp. 1 -5, Dresden, Germany, June 2013.

In the fifth generation mobile communication system, for example, the emergence of services requiring low delay different from the conventional level, such as haptic communication and augmented reality, is expected, and ultra-high reliability and low delay communication (URLLC: Ultra-Reliable) and Low-Latency Communications) is one of the functional requirements. Therefore, for example, in LTE, which is a fourth generation mobile communication system, a delay of 10 [milliseconds] is assumed as a delay from a transmission source to a transmission destination of a packet in a wireless section, while a fifth generation mobile communication system In this, it is aimed to realize a delay of 1 [millisecond] or less.

In the prior art, for each wireless terminal in which the downlink data signal is multiplexed on the same wireless resource in time and frequency, the wireless base station is configured to transmit information for demodulating the downlink data signal addressed to the other terminal to each wireless terminal. Notify via downlink control information addressed to. Thus, not only the information for demodulating the downlink data signal for the own terminal but also the information for demodulating the downlink data signal for the other terminal is acquired by performing a blind search for the downlink control information for the own terminal. be able to. However, there is a problem that information for demodulating a downlink data signal is redundantly transmitted, and the utilization efficiency of radio resources is reduced.

The disclosed technology improves the transmission efficiency of the information related to the interference component in the non-orthogonal multiple access system under consideration of application to the fifth generation mobile communication system etc., while also achieving the functional requirements of ultra-reliable and low delay communication. An object of the present invention is to provide a wireless communication system, a wireless base station, and a wireless terminal that can be satisfied.

According to one aspect of the present disclosure, a wireless communication system capable of providing a wireless service in a non-orthogonal multiple access scheme includes a wireless base station and a plurality of wireless terminals.

According to an aspect of the present disclosure, a radio base station in a radio communication system is configured to transmit a first radio terminal and a first radio terminal for multiplexing downlink data signals on the same downlink radio resource according to a non-orthogonal multiple access scheme, A process of selecting a second wireless terminal, and a second downlink control information addressed to the second wireless terminal in first downlink control information which is downlink control information related to a first downlink data signal addressed to the first wireless terminal Storing the reference information indicating the position of the radio resource in which the second downlink control information, which is the downlink control information related to the downlink data signal, is arranged, the first downlink control information, and the second downlink control information A process of transmitting, using a wireless communication circuit, a downlink signal in which the first downlink data signal and the second downlink data signal are arranged;
Processing circuitry to perform the

According to an aspect of the present disclosure, a first wireless terminal in a wireless communication system acquires first downlink control information addressed to the first wireless terminal from the downlink signal transmitted by the wireless base station. Processing for acquiring the second downlink control information addressed to the second wireless terminal based on the reference information acquired from the first downlink control information, and the second downlink control information. Processing for receiving the second downlink data signal addressed to the second radio terminal, processing for removing an interference component by the second downlink data signal from the downlink signal, and And processing for receiving the first downlink data signal addressed to the first wireless terminal based on the first downlink control information from the downlink signal after removal.

According to one aspect of the disclosed technology, ultra-reliability and low delay while improving the transmission efficiency of information related to interference components in non-orthogonal multiple access systems that are being considered for application to fifth generation mobile communication systems and the like. It becomes possible to satisfy the functional requirements of communication.

FIG. 1 is a diagram showing a schematic configuration of the wireless communication system 1 according to the first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the downlink signal in the wireless communication system according to the first embodiment. FIG. 3 is a diagram schematically illustrating downlink control information addressed to a first wireless terminal and downlink control information addressed to a second wireless terminal. FIG. 4 is a diagram showing an example of the content of reference information. FIG. 5 schematically shows the arrangement of radio resources and downlink control information in the control area. FIG. 6 is a diagram illustrating an example of the flow of processing in the wireless terminal 10 according to the first embodiment. FIG. 7 is a diagram showing an example of contents of second downlink control information. FIG. 8 is a diagram illustrating an example of the flow of processing in the wireless base station 20 according to the first embodiment. FIG. 9 is a diagram illustrating an example of contents of reference information according to the second embodiment. FIG. 10 is a diagram of an example of contents of reference information according to the third embodiment. FIG. 11 is a diagram illustrating an example of contents of reference information according to the first modification. FIG. 12 is a diagram showing an example of a hardware configuration of the wireless terminal 10 and the wireless base station 20 in the wireless communication system 1.

Hereinafter, embodiments of a wireless communication system, a wireless base station, and a wireless terminal disclosed in the present application will be described in detail with reference to the drawings. Note that the following embodiments do not limit the disclosed technology. Further, it goes without saying that the embodiments shown below may be implemented in combination as appropriate. Here, the entire contents of Non Patent Literature 1 to Non Patent Literature 19 are incorporated herein by reference.

First Embodiment FIG. 1 is a diagram showing a schematic configuration of a wireless communication system 1 according to a first embodiment. The wireless communication system 1 illustrated in FIG. 1 is also referred to as a first wireless terminal 10A (also referred to as a wireless terminal 10A or UE # 1) and a second wireless terminal 10B (also referred to as a wireless terminal 10B or UE # 2). And a wireless base station 20. The first wireless terminal 10A and the second wireless terminal 10B exist in an area 30 (also referred to as a cell, a macro cell, a small cell, a pico cell, a sector, a zone, etc.) of a wireless service provided by the wireless base station 20. It is configured to be able to receive downlink signals transmitted from the radio base station 20. The radio base station 20 according to the first embodiment may be configured to perform radio communication with the first radio terminal 10A and the second radio terminal 10B in a non-orthogonal multiple access scheme. In the example shown in FIG. 1, the first wireless terminal 10A and the second wireless terminal 10B are illustrated for simplification of the description, but three or more wireless terminals may be present. The first wireless terminal 10A and the second wireless terminal 10B may be collectively referred to as a wireless terminal 10 as a concept. For the first wireless terminal 10A, the own terminal is the first wireless terminal 10A, and the other terminals mean other wireless terminals including the second wireless terminal 10B. For the second wireless terminal 10B, the own terminal is the second wireless terminal 10B, and the other terminals mean other wireless terminals including the first wireless terminal 10A.

The wireless base station 20 of the non-orthogonal multiple access scheme combines the first wireless terminal 10A and the second wireless terminal 10B with the same wireless resource in time and frequency among a plurality of wireless resources defined by frequency and time. The small transmission power is allocated to the first wireless terminal 10A located near the wireless base station 20, and the large transmission power to the second wireless terminal 10B located far from the wireless base station 20. Assign In other words, since the first wireless terminal 10A is located near the wireless base station 20, the propagation loss of the downlink signal from the wireless base station 20 may be relatively small. On the other hand, since the second radio terminal 10B is located far from the radio base station 20, the propagation loss of the downlink signal from the radio base station 20 is relatively large. Therefore, the radio base station 20 is expected to compensate for the attenuation due to the propagation loss by allocating more transmission power to the second radio terminal 10B than to the first radio terminal 10A.

In the non-orthogonal multiple access scheme, when the second wireless terminal 10B receives a downlink signal from the wireless base station 20, a downlink data signal (also referred to as a second data signal) addressed to the second wireless terminal 10B. And a downlink data signal addressed to the second radio terminal 10B addressed to the own terminal from the radio resource in which the downlink data signal (also referred to as the first data signal) addressed to the first radio terminal 10A is multiplexed. To get At this time, due to the propagation loss from the wireless base station 20 to the second wireless terminal 10B, the downlink data signal for the first wireless terminal 10A among the downlink signals from the wireless base station 20 is reduced to a negligible extent. Do. Therefore, when acquiring the downlink data signal addressed to the second radio terminal 10B addressed to the second radio terminal 10B, the second radio terminal 10B does not consider the influence of the downlink data signal addressed to the first radio terminal 10A. Also good. In other words, for the second radio terminal 10B, interference components due to the downlink data signal for the first radio terminal 10A can be ignored.

On the other hand, when the first radio terminal 10A receives the downlink signal from the radio base station 20, the transmission power of the downlink data signal for the second radio terminal 10B multiplexed in the same radio resource in time and frequency Therefore, it is desirable to remove the interference component due to the downlink data signal for the second wireless terminal 10B. In other words, when acquiring the downlink data signal addressed to the first wireless terminal 10A addressed to the first wireless terminal 10A, the first wireless terminal 10A demodulates the downlink data signal addressed to the second wireless terminal 10B. It is desirable to remove the interference component based on the acquired and acquired downlink data signal for the second radio terminal 10B. In other words, for the first radio terminal 10A, the interference component due to the downlink data signal for the second radio terminal 10B may not be of a negligible size.

By the way, the radio terminals 10A and 10B in the radio communication system 1 determine whether or not there is a downlink data signal for the own terminal in the downlink signal from the radio base station 20 based on the downlink control information for the own terminal. It may be configured to

FIG. 2 is a diagram illustrating an example of the configuration of the downlink signal in the wireless communication system according to the first embodiment. The configuration of the downlink signal illustrated in FIG. 2 schematically shows a subframe which is one component of a radio frame, and in a space defined using time on the horizontal axis and frequency on the vertical axis, It has a control area and a data area. In other words, the downlink signal (also referred to as downlink subframe) has a plurality of radio resources defined at least on the frequency axis and the time axis. Each of the plurality of radio resources is configured to be distinguishable by a resource number assigned to each of a predetermined number of radio resources. The resource number may be a single value or may be defined by a value on the frequency axis and a value on the time axis. In other words, the resource number in the present disclosure may be a value useful for specifying the location of the radio resource, and is not limited to any one concept. For example, the term "resource number" may also be described in the case of indicating the position of the radio resource in which the downlink data signal is arranged, and the term "resource number" also in the case of indicating the position of the radio resource May be explained in terms of However, in the present disclosure, the “resource number” in the case of indicating the position of the radio resource in which the downlink data signal is arranged and the “resource number” in the case of indicating the position of the radio resource in which the downlink control information is arranged are necessarily It should be noted that the concepts are not necessarily at the same level. For example, while radio resources in the control area in which downlink control information is allocated are specified in units of CCE (Control Channel Element), radio resources in a data area in which downlink data signals are allocated are specified in a unit different from CCE. It may be done. As described above, in the present disclosure, although the term “resource number” may be used in any case for simplification of the description, it should be appropriately read and understood based on the above-described meaning. The CCE number (also referred to as a CCE index number) for specifying the above-mentioned CCE-based radio resource is an example of a resource number assigned to the radio resource in the control area.

The control region illustrated in FIG. 2 is formed by a set of radio resources located forward in the time axis, and may be referred to, for example, as PDCCH (Physical Downlink Control CHannel). The data area illustrated in FIG. 2 is formed by a set of radio resources located behind the control area on the time axis, and may be referred to as, for example, PDSCH (Physical Downlink Shared CHannel).

In the control area, downlink control information (DCI) can be stored for each wireless terminal. In the example shown in FIG. 2, the downlink control information DCI # 1 addressed to the first radio terminal 10A to which the downlink data radio resource # 1 is assigned in the data area, and the same downlink data radio resource as the first radio terminal 10A Downlink control information DCI # 2 addressed to the second radio terminal 10B to which # 1 is assigned is stored in the control area.

In the downlink control information, as will be described in detail later, information required when acquiring the downlink data signal addressed to the own terminal multiplexed in the downlink data radio resource allocated to the corresponding radio terminal 10 (Also referred to as radio resource information) is stored. The radio resource information may include, for example, information indicating the position of the allocated downlink data radio resource, information indicating a modulation scheme, and the like. The radio terminal performs demodulation / decoding processing (processing such as demodulation, reception, etc.) of the downlink data signal addressed to the own terminal multiplexed to the corresponding downlink data radio resource based on the radio resource information in the downlink control information directed to the own terminal Processing (also referred to as processing).

As described above, in the non-orthogonal multiple access scheme, there are cases in which a downlink data signal addressed to another terminal is multiplexed in the downlink data radio resource allocated to the own terminal. Therefore, before the radio terminal demodulates and decodes the downlink data signal for the own terminal, the radio terminal demodulates based on the radio resource information for the other terminal to acquire the downlink data signal for the other terminal, and acquires the other terminal Processing may be performed to suppress the interference component using the downlink data signal addressed to.

The suppression process of the interference component in the wireless communication system 1 according to the first embodiment may be, for example, a successive interference cancellation (SIC) scheme. In the successive interference cancellation method, a wireless base station transmits a signal multiplexed on the transmission power axis to two or more wireless terminals having different signal to noise ratios (SN ratios), and a wireless terminal having a large SN ratio Is a technique in which a desired signal is taken out by performing interference cancellation one after another. In the successive interference cancellation method, a symbol level interference cancellation (SLIC) method that removes (or suppresses) interference components at a symbol level and a codeword level that removes (or suppresses) interference components at a codeword level There is a method of interference cancellation (CWIC: Codeword Level Interference Cancellation). In addition, the suppression processing of the interference component in the wireless communication system 1 according to the first embodiment is a method of selecting the pattern closest to the desired signal from the combinations of all the signal points that the downlink signal can take. It may be a detection (MLD: Maximum Likelihood Detection) method. The present embodiment is applicable to any method. Then, in any of the schemes, obtaining information on the downlink data signal addressed to the other terminal multiplexed to the same downlink data radio resource eliminates the interference component from the downlink signal from the radio base station 20 and It is useful in shortening the time required to acquire the downlink data signal addressed to the terminal. In other words, for wireless terminals with high SN ratio, obtaining information on downlink data signals addressed to other terminals multiplexed in the same downlink data radio resource is extremely reliable and low delay in the fifth generation mobile communication system. It is important to realize communication.

FIG. 3 is a diagram schematically illustrating downlink control information addressed to a first wireless terminal and downlink control information addressed to a second wireless terminal. In the example shown in FIG. 3, the downlink control information DCI # 1 addressed to the first wireless terminal relates to the downlink control information DCI # 2 addressed to the second wireless terminal (also referred to as another terminal for the first wireless terminal). Reference information D10, radio resource information D11 necessary for receiving a downlink data signal addressed to the first wireless terminal (also referred to as the own terminal for the first wireless terminal), downlink control information addressed to the first wireless terminal It has an error detection code D12 necessary for error detection processing of DCI # 1. Among the contents of the downlink control information DCI # 1, the error detection code D12 is scrambled by the identification information on the first wireless terminal 10A, and may be descrambled based on the identification information on the first wireless terminal 10A. Configured to be able to Among the contents of the downlink control information DCI # 1, the reference information D10 and the radio resource information D11 may not be the target of scrambling based on the identification information on the first radio terminal 10A. The identification information related to the first radio terminal 10A may also be referred to as Radio Network Temporary Identifier (RNTI) or C-RNTI (Cell RNTI). The reference information D10 illustrated in FIG. 3 may be referred to, for example, as position designation information, association information, pointer information, link information, and the like.

In the example shown in FIG. 3, the downlink control information DCI # 2 addressed to the second wireless terminal is necessary for receiving the downlink data signal addressed to the second wireless terminal (also referred to as the own terminal for the second wireless terminal). Radio resource information D21, and an error detection code D22 necessary for error detection processing of downlink control information DCI # 2 addressed to the second radio terminal. Among the contents of the downlink control information DCI # 2, the error detection code D22 is scrambled by the identification information on the second radio terminal 10B, and may be descrambled based on the identification information on the second radio terminal 10B. Configured to be able to Of the contents of the downlink control information DCI # 2, the radio resource information D21 may not be the target of scrambling based on the identification information on the second radio terminal 10B. The identification information on the second radio terminal 10B may also be referred to as Radio Network Temporary Identifier (RNTI) or C-RNTI (Cell RNTI).

The reference information D10 indicates the position of the radio resource to which the downlink control information for another terminal is mapped among the radio resources in the control area. In the example shown in FIG. 3, reference information D10 stored in downlink control information DCI # 1 addressed to the first wireless terminal is in the control area to which downlink control information DCI # 2 addressed to the second wireless terminal is mapped. Indicates the position. Thereby, the first wireless terminal 10A acquires the downlink control information DCI # 2 addressed to the second wireless terminal based on the reference information stored in the downlink control information DCI # 1 addressed to the first wireless terminal. It is possible to execute reception processing for the downlink data signal addressed to the second wireless terminal based on the radio resource information D21 stored in the acquired downlink control information DCI # 2.

FIG. 4 is a diagram showing an example of the content of reference information. In the example illustrated in FIG. 4, the reference information D10 includes start position information D101 indicating the position of the top of the radio resource to which downlink control information of other terminals is mapped, and size information D102 indicating the length of the radio resource. .

FIG. 5 schematically shows the arrangement of radio resources and downlink control information in the control area. In the example shown in FIG. 5, there are a total of 33 CCEs of index numbers 0 to 32 as radio resources (CCE: Control Channel Element) in the control area. The downlink control information DCI # 1 addressed to the first wireless terminal is arranged (mapped) in a set of a CCE with index number 16 and a CCE with number 17. The downlink control information DCI # 2 addressed to the second wireless terminal is arranged in a set of CCE with index number 22 and CCE with number 23.

In the example shown in FIG. 5, the reference information D10 stored in the downlink control information DCI # 1 addressed to the first wireless terminal indicates the position of the CCE where the downlink control information DCI # 2 addressed to the second wireless terminal is arranged. Show. The reference information D10 is, for example, the index number (22 in the example of FIG. 5) of the CCE at the head (left side in FIG. 5) in the set of CCEs in which the downlink control information DCI # 2 addressed to the second radio terminal is arranged As start position information D101. According to the example shown in FIG. 5, the CCE in the control area has a total of 33 index numbers from 0 to 32 and all index numbers can be represented by 6 bits, so the data length of the start position information D101 Should have 6 bits.

The reference information D10 has, for example, the length (2 in the example of FIG. 5) of the set of CCEs in which the downlink control information DCI # 2 addressed to the second wireless terminal is arranged, as size information. The size information D102 may be referred to as an aggregation level. The aggregation level may be configured to have, for example, four stages of level 1, level 2, level 4 and level 8. When the aggregation level is level 1, the set of CCEs to which downlink control information is mapped is 1 in length. When the aggregation level is level 2, the set of CCEs to which downlink control information is mapped is 2 in length. When the aggregation level is level 4, the set of CCEs to which downlink control information is mapped is 4 in length. When the aggregation level is level 8, the set of CCEs to which downlink control information is mapped is of length 8. According to this example, since all aggregation levels can be represented by 2 bits, the data length of the size information D 102 may be 2 bits.

As described above, when the first radio terminal 10A succeeds in detecting the downlink control information DCI # 1 addressed to the first radio terminal, for example, by blind search of the radio resources in the control area, the downlink control information DCI Based on the reference information D10 in # 1, downlink control information DCI # 2 directed to the second wireless terminal can be obtained. In other words, the first radio terminal 10A can omit the blind search of the downlink control information DCI # 2 addressed to the second radio terminal by using the reference information D10. Therefore, the first wireless terminal 10A can shorten the time required to acquire the downlink control information DCI # 2 addressed to the second wireless terminal, as compared with the time required for the blind search. Moreover, since the reference information is, for example, a total of 8 bits of start position information D101 of 6 bit length and size information D102 of 2 bit length, for transmission of information necessary for interference cancellation in non-orthogonal multiple access system Can reduce the amount of data that increases. In other words, in the above-mentioned prior art, the information for acquiring the downlink data signal addressed to the second wireless terminal includes downlink control information addressed to the second wireless terminal and downlink control addressed to the first wireless terminal Although information is redundantly transmitted and received, according to the first embodiment, such duplication can be avoided. Such an aspect is for ultra-high reliability and low delay communication while improving transmission efficiency of information necessary for interference cancellation in a non-orthogonal multiple access system under consideration of application to the fifth generation mobile communication system and the like. Useful for meeting functional requirements.

FIG. 6 is a diagram illustrating an example of the flow of processing in the wireless terminal 10 according to the first embodiment. In the flow of the process shown in FIG. 6, for example, downlink control information addressed to the own terminal is searched by searching for downlink control information addressed to the own terminal (also referred to as blind search) in the control region of the subframe illustrated in FIG. The execution may be started when the information detection is successful. In the search for downlink control information addressed to the own terminal, the error detection code attached to the downlink control information is descrambled with the identification information on the own terminal, and the error detection code after descrambling detects the error for the downlink control information Is done. As a result, when an error that can not be cured is not detected in the downlink control information, the radio terminal 10 determines that the detection of downlink control information addressed to the own terminal has succeeded. On the other hand, when an error that can not be cured is detected in the downlink control information, the radio terminal 10 may determine that the downlink control information is downlink control information directed to another terminal.

The radio terminal 10 acquires, from the downlink signal transmitted by the radio base station 20, first downlink control information that is downlink control information directed to the own terminal (S101). According to the example illustrated in FIG. 2, in processing S101, the radio terminal 10 acquires the first downlink control information DCI # 1 arranged in the control area. Then, the radio terminal 10 determines whether reference information is present in the first downlink control information (S102).

In processing S102, the wireless terminal 10 may determine, for example, based on the data length of the first downlink control information acquired in processing S101, whether reference information is present. According to the example shown in FIG. 3, in the downlink control information DCI # 1 in which the reference information D10 is stored and the downlink control information DCI # 2 in which the reference information D10 is not stored, at least the area for storing the reference information D10 In the case of a minute, a difference occurs in data length. Therefore, in the process S102, the wireless terminal 10 determines whether the reference information exists by determining whether the data length of the first downlink control information corresponds to the data length of the downlink control information including the reference information. You may judge. Alternatively, the first downlink control information may include format information indicating whether it is downlink control information including reference information. That is, in processing S102, the radio terminal 10 may determine whether reference information exists based on the format information of the first downlink control information.

In step S102, when it is determined that the reference information exists in the first downlink control information (YES in S102), the radio terminal 10 determines from the downlink signal transmitted from the radio base station 20 from the first downlink control information. Based on the acquired reference information, second downlink control information that is downlink control information addressed to another terminal is acquired (S103). According to the example shown in FIG. 2, the radio terminal 10 acquires the downlink control information DCI # 2 addressed to the other terminal based on the reference information acquired from the first downlink control information DCI # 1.

In processing S103, the radio terminal 10 may ignore the error detection code in the second downlink control information. This is because, as described above, the error detection code in the second downlink control information is scrambled based on the identification information on another terminal that is the original destination of the second downlink control information, This is because the content is meaningless unless descrambling is performed using the identification information.

In addition, in process S103, when ignoring the error detection code | symbol of 2nd downlink control information, the radio | wireless terminal 10 does not need to perform error detection about the content of 2nd downlink control information. Here, that the first downlink control information includes the reference information means that the radio base station 20 instructs the radio terminal 10 to execute the interference removal process in the non-orthogonal multiple access system. Means In other words, the radio base station 20 transmits the first downlink control information including the reference information to the radio terminal 10 having a high SN ratio. This is because, in the orthogonal multiple access scheme, the radio base station 20 allocates small transmission power to the radio terminal 10 having a high SN ratio, and allocates large transmission power to the radio terminal 10 having a low SN ratio.

Generally, the high SN ratio means that the wireless terminal 10 exists in the vicinity of the wireless base station 20 and the degree of influence of noise on a desired signal is low. Similarly, for the radio terminal 10 having a high SN ratio, the degree of influence of noise on control information directed to other terminals is also low. Therefore, when the radio terminal 10 having a high SN ratio receives downlink control information addressed to another terminal stored in the control area of the downlink signal transmitted by the radio base station 20, the degree of influence of noise can be ignored. This has the aspect of reducing the information needed for interference cancellation in non-orthogonal multiple access schemes. In other words, in the wireless communication system 1 according to the first embodiment, it is not necessary to notify the wireless terminal of identification information for descrambling the CRC of the downlink control information addressed to the other terminal. When identification information such as RNTI or C-RNTI of another terminal is required for descrambling the CRC of downlink control information addressed to the other terminal, the radio communication system according to the first embodiment stores the identification information. For example, an area of 16 bits in length, which is an area of

The radio terminal 10 acquires radio resource information stored in the second downlink control information, and based on the radio resource information acquired from the second downlink control information, a second downlink that is a downlink data signal addressed to another terminal A data signal is received (S104). According to the example shown in FIG. 2, in the processing S104, the radio terminal 10 is multiplexed with the downlink data radio resource # 1 based on the radio resource information acquired from the second downlink control information DCI # 2. Receive the downlink data signal addressed to the terminal.

FIG. 7 is a diagram showing an example of contents of second downlink control information. The second downlink control information illustrated in FIG. 7 includes a first information element (Resource allocation header) D201 of 1 bit and a second information element (Resource block assignment for bit length) determined according to the system band of the downlink signal. RA Type 0) D202, 2-bit third information element (TPC for PUCCH) D203, 2-bit fourth information element (Downlink Assignment Index) D 204, two-way wireless communication method between wireless terminal and wireless base station A fifth information element (HARQ Process) D205 with a bit length determined according to whether Time Division Duplex (TDD) or Frequency Division Duplex (FDD) is used as one of Sixth information element (Transport block to codeword swap flag) D206, 5-bit seventh information element (MCS for Transport Block 1) D207, 1-bit eighth information element (NDI for Transpo) rt Block 1) D208, 2-bit ninth information element (RV for Transport Block 1) D209, 5-bit tenth information element (MCS for Transport Block 2) D210, and 1-bit eleventh information element ( NDI for Transport Block 2) having D211, 2-bit 12th information element (RV for Transport Block 2) D212, and 13th information element (Precoding information) D213 of bit length determined according to the number of antenna ports . Among the information elements D201 to D213 illustrated in FIG. 7, the information elements corresponding to the radio resource information D21 of the second downlink control information DCI # 2 shown in FIG. 3 are the sixth information element D206 to the thirteenth information element There are eight information elements up to D213. Based on the eight information elements from the sixth information element D206 to the thirteenth information element D213 illustrated in FIG. 7, the radio terminal 10 downlink data addressed to the other terminal multiplexed in the downlink data radio resource # 1. A signal may be received. However, the present disclosure is not limited to the contents of the second downlink control information illustrated in FIG. 7. For the purpose of each information element illustrated in FIG. 7, technical common sense shown in the above-mentioned Non-Patent Documents 1 to 19 is incorporated.

The radio terminal 10 executes a process of removing an interference component from the downlink signal of the downlink data radio resource # 1 based on the second downlink data signal acquired in the process S104 (S105).

The radio terminal 10 performs a first downlink data signal that is a downlink data signal for the own terminal, based on the radio resource information of the first downlink control information, for the downlink signal after removing the interference component in processing S105. It receives (S106). Thereby, the radio terminal 10 receives the downlink data signal addressed to the own terminal while suppressing the influence of the interference component by the downlink data signal addressed to the other terminal multiplexed to the same radio resource by the non-orthogonal multiple access scheme. Can.

On the other hand, when it is determined in the processing S102 that the reference information does not exist in the first downlink control information (NO in S102), the radio terminal 10 omits the execution of the processing S103 to the processing S105 described above. The reason is that the reference information does not exist in the first downlink control information means that the radio base station 20 does not instruct the radio terminal 10 to execute the interference cancellation process in the non-orthogonal multiple access system. In order to In this case, the radio terminal 10, in the processing S106, for the downlink signal for which the interference removal in the non-orthogonal multiple access scheme is not performed, based on the radio resource information of the first downlink control information, To receive the first downlink data signal (S106).

The above is an example of the flow of processing in the wireless terminal 10 according to the first embodiment. The first embodiment is not limited to the case where one reference information is stored in the first downlink control information. For example, one or more pieces of reference information may be stored in one piece of first downlink control information. In that case, in the example shown in FIG. 6, the processing S103 to the processing S105 may be executed by the number of reference information stored in the first downlink control information.

FIG. 8 is a diagram illustrating an example of the flow of processing in the wireless base station 20 according to the first embodiment. The flow of the process illustrated in FIG. 8 may start to be performed, for example, when generating a downlink signal as illustrated in FIG. 2.

The radio base station 20 selects a first radio terminal and a second radio terminal on which downlink data signals are multiplexed on the same radio resource by the non-orthogonal multiple access scheme (S201). In process S201, the radio base station 20 sets the first radio terminal having a high SN ratio among the radio terminals for which downlink data (also referred to as downlink data, DL data, etc.) exist in the transmission buffer for each radio terminal. It may be selected as a wireless terminal, and a wireless terminal having a low SN ratio may be selected as a second wireless terminal. Whether the SN ratio is high or low may be determined, for example, by comparing a value corresponding to the SN ratio with a threshold. Alternatively, whether the SN ratio is relatively high or low may be determined by comparing values corresponding to the SN ratios of the wireless terminals.

It is assumed that the SN ratio of each wireless terminal 10 referred to in the process S201 is known to the wireless base station 20 based on a measurement result report (also referred to as Measurement report) from the wireless terminal 10 or the like. The measurement result report from the radio terminal 10 does not necessarily have to store the value of the SN ratio, and changes in proportion to the SN ratio of the downlink signal from the radio base station 20 observed in the radio terminal 10 Any value may be used as long as it has a value (also referred to as “a value corresponding to the SN ratio”). In other words, the radio base station 20 according to the first embodiment may determine that the SN ratio is high or the SN ratio is low based on another value different from the value of the SN ratio. The “value corresponding to the SN ratio” in the present disclosure may be referred to as, for example, a CQI (Channel Quality Indicator) or a CSI (Channel Status Information), or a coding rate (Coding Rate). , Or may be referred to as a modulation coding scheme (MCS), may be referred to as an MCS index, or may be referred to as a transport block size (TBS). For example, as the SN ratio of the wireless terminal is higher, a modulation scheme with a higher coding rate (in other words, a modulation scheme with a larger MCS index value) is selected, and the TBS becomes larger. On the other hand, as the SN ratio of the wireless terminal is lower, a modulation scheme with a lower coding rate (in other words, a modulation scheme with a smaller MCS index value) is selected, and the TBS becomes smaller.

In process S201, the wireless base station 20 may select one or more first wireless terminals, or may select one or more second wireless terminals. In other words, in the first embodiment, it is not intended to limit the number of first wireless terminals and the number of second wireless terminals.

The radio base station 20 selects a radio resource (also referred to as a second radio resource) of the control area to be allocated to the second downlink control information which is downlink control information for the second radio terminal (S202) ). In process S202, the radio base station 20 determines the number of connections (also referred to as an aggregation level), which is the number of radio resources to be allocated to downlink control information, based on the value indicated in the measurement result report of the second radio terminal. It determines and selects the radio resource according to the number of connection. In the example illustrated in FIG. 5, a set of the radio resource CCE [22] and the radio resource CCE [23] is selected for the second downlink control information DCI # 2 directed to the second radio terminal. That is, the number of connections in this example is two.

The radio base station 20 generates reference information indicating the position of the second radio resource (S203). In process S203, the radio base station 20 refers to the start position information having the index number of the first radio resource in the set of radio resources selected in process S202, and the size information having the number of connections determined in process S202. You may store in.

The radio base station 20 stores the reference information generated in the processing S203 in first downlink control information which is downlink control information addressed to the first wireless terminal (S204). As a result, first downlink control information DCI # 1 having reference information as illustrated in FIG. 3 is generated.

The radio base station 20 sets the first downlink control information DCI # 1 addressed to the first wireless terminal and the second downlink control information DCI # 2 addressed to the second wireless terminal in the control area of the downlink signal. It arranges (S205). At that time, the error detection code D12 of the first downlink control information DCI # 1 is arranged in a scrambled format with the identification information on the first wireless terminal corresponding to the first downlink control information DCI # 1. The error detection code D22 of the second downlink control information DCI # 2 is arranged in a scrambled form with the identification information on the second wireless terminal corresponding to the second downlink control information DCI # 2.

The radio base station 20 performs non-orthogonal multiplexing on a first downlink data signal that is a downlink data signal for the first wireless terminal and a second downlink data signal that is a downlink data signal for the second wireless terminal. It multiplexes to the data area of a downlink signal by a connection system (S206). At that time, transmission power smaller than the transmission power allocated to the second downlink data signal is allocated to the first downlink data signal. In other words, transmission power greater than the transmission power allocated to the first downlink data signal is allocated to the second downlink data signal. Here, as described above, the first wireless terminal is a wireless terminal having a higher SN ratio than the second wireless terminal. Also, as a result of processing S206, downlink signals as illustrated in FIG. 2 are generated. In the example shown in FIG. 2, for simplification of the description, the first downlink data signal and the downlink data radio resource # 1 to which the first downlink data signal and the second downlink data signal are multiplexed are used. The related first downlink control information DCI # 1 and the second downlink control information DCI # 2 related to the second downlink data signal are illustrated, and the others are omitted. For the detailed structure of the downlink signal, refer to Non-Patent Documents 1 to 19 described above.

The wireless terminal 20 transmits the generated downlink signal to the area 30 of the wireless service as illustrated in FIG. 1 (S207).

The above is an example of the flow of processing in the radio base station 20 according to the first embodiment.

According to the first embodiment, the blind search is performed based on the identification information of the other terminal, since the information indicating the position of the radio resource in which the downlink control information for the other terminal is arranged is added to the downlink control information and transmitted. Compared to the above, it is possible to shorten the time until acquiring downlink control information addressed to another terminal. In addition, since information on identification information of other terminals is added to downlink control information and notification can be omitted, information on interference components can be compressed accordingly. In addition, since descrambling processing based on identification information of another terminal can be omitted, processing time can be shortened. Such an action is useful for realizing ultra-reliable low-latency communication while improving the transmission efficiency of information related to interference components.

Second Embodiment FIG. 9 is a diagram illustrating an example of contents of reference information according to a second embodiment. The reference information illustrated in FIG. 9 further includes a second error detection code D103 in addition to the content example of the reference information according to the first embodiment. The second error detection code D103 is an error detection code of downlink control information addressed to the other terminal, and is an error detection code before being scrambled based on the identification information of the other terminal.

In the second embodiment, when the radio terminal 10 acquires downlink control information for another terminal based on the reference information, based on the second error detection information acquired from the reference information, the radio terminal 10 transmits downlink for the other terminal acquired. Error detection can be performed on control information.

Next, the flow of processing in the wireless terminal 10 according to the second embodiment will be briefly described. The flow of the process in the wireless terminal 10 according to the second embodiment is the same as the flow of the process in the wireless terminal 10 according to the first embodiment illustrated in FIG. 6, and therefore, the example illustrated in FIG. That is, in the process S103 shown in FIG. 6, the wireless terminal 10 acquires the start position information D101 and the size information D102 from the reference information, and based on the start position information D101 and the size information D102, the second terminal addressed to the other terminal. Get downlink control information. In step S103 according to the second embodiment, the wireless terminal 10 further performs error detection on the second downlink control information based on the second error detection code D103 acquired from the reference information. Thereby, the radio terminal 10 according to the second embodiment can determine the reliability of the second downlink control information based on the second error detection code D103.

When the wireless terminal 10 detects an error that can not be corrected to the second downlink control information by the error detection based on the second error detection code D103 in the process S103 according to the second embodiment, the process from S104 to S105 is performed. The processing may be omitted. As a result of omitting the processes of steps S104 to S105, the wireless terminal 10 may fail to receive the first downlink data signal addressed to the own terminal in step S106. If the reception of the first downlink data signal addressed to the own terminal fails, the wireless base station 20 may be requested to retransmit the first downlink data signal.

The above is the flow of processing in the radio terminal 10 according to the second embodiment. In the process flow shown in FIG. 6, the processes not described as the process flow in the wireless terminal 10 according to the second embodiment described above are the same as those in the first embodiment, and thus duplicate descriptions are omitted. by.

Next, the flow of processing in the radio base station 20 according to the second embodiment will be briefly described. The flow of the process in the wireless base station 20 according to the second embodiment is the same as the flow of the process in the wireless base station 20 according to the first embodiment illustrated in FIG. 8 and therefore, the example illustrated in FIG. . That is, in the process S203 shown in FIG. 8, the radio base station 20 according to the second embodiment not only generates reference information indicating the position of the second radio resource, but also performs downlink control for the second radio terminal. A second error detection code, which is an error detection code used for error detection of information, is stored in the reference information. According to the example shown in FIG. 3, the second error detection code is used for error detection of radio resource information D21 of downlink control information DCI # 2 addressed to the second radio terminal. However, unlike the error detection code D22 stored in the downlink control information DCI # 2 directed to the second wireless terminal, the second error detection code is scrambled by the identification information on the second wireless terminal. Absent.

The processes after step S204 are the same as in the first embodiment, and thus the description thereof is omitted.

The above is the flow of processing in the radio base station 20 according to the second embodiment. In the process flow shown in FIG. 8, the processes not described as the process flow in the radio base station 20 according to the second embodiment described above are the same as those in the first embodiment, and thus the redundant description is omitted. It depends.

According to the second embodiment, since the error detection code of the downlink control information addressed to the other terminal is added to the downlink control information addressed to the own terminal and notified, the radio terminal 10 uses the identification information of the other terminal to use the other terminal. As compared with the operation of performing blind search on downlink control information addressed to a terminal, it is possible to shorten the time until the result of error detection for downlink control information addressed to another terminal is obtained. Such an action is useful for realizing ultra-reliable low-latency communication while improving the transmission efficiency of information related to interference components.

Third Embodiment FIG. 10 is a diagram illustrating an example of contents of reference information according to a third embodiment. The reference information illustrated in FIG. 10 has a third error detection code D104 in addition to the content example of the reference information according to the first embodiment, similarly to the reference information according to the second embodiment shown in FIG. Unlike the second error detection code D103, the third error detection code D104 is an error detection code related to a partial area of downlink control information for another terminal. As illustrated in FIG. 7, various parameters are set in the downlink control information. However, the parameters of the downlink control information required to remove the interference component due to the downlink data signal destined for another terminal multiplexed by the non-orthogonal multiple access scheme are not all but some of the parameters illustrated in FIG. 7 . Therefore, in the third embodiment, the error detection code generated for the set of parameters necessary for estimation of the interference component is stored in the reference information as the third error code D104. Thereby, the code length of the error detection code can be further compressed than the second error detection code D103 which is the error detection code for the entire downlink control information.

The flow of processing in the radio terminal 10 and the radio base station 20 according to the third embodiment is the same as that of the second embodiment. However, when generating the third error detection code D104, the radio base station 20 according to the third embodiment may perform processing in accordance with the above-described purpose. For example, when the radio base station 20 according to the third embodiment generates the first downlink control information addressed to the first radio terminal 10A, all of the second downlink control information addressed to the second radio terminal 10B is generated. Instead, the third error detection code D104 may be generated based on a set of parameters necessary for estimation of the interference component. An example of a set of parameters necessary for estimation of interference components is, for example, eight information elements from the sixth information element D206 to the thirteenth information element D213 illustrated in FIG.

When the wireless terminal 10 according to the third embodiment also performs error detection based on the third error detection code D104, the process may be performed in accordance with the above-described purpose. For example, when the first wireless terminal 10A according to the third embodiment performs error detection based on the third error detection code D104, the first wireless terminal 10A makes an error with respect to all of the second downlink control information acquired based on the reference information. Instead of performing detection, error detection may be performed on a set of parameters required to estimate an interference component.

According to the third embodiment, the third error detection code D104 can compress the code length of the error detection code more than the second error detection code D103 which is the error detection code for the entire downlink control information. . Such an action is further useful for realizing ultra-reliable low-latency communication while improving the transmission efficiency of information on interference components.

<Modification 1> FIG. 11 is a diagram showing an example of contents of reference information according to Modification 1. As shown in FIG. The reference information illustrated in FIG. 11 is a 2-bit first information element (the number of other terminals DCI mapping information) D220 and three second information elements (the other terminal information [1] to the other terminal information [3]) D230 , D240 and D250. Each of the second information elements D230, D240, D250 has a 2-bit first sub information element (Aggregation Level Index) D231 and a 6-bit second sub information element (start CCE) D232, The information element indicates the position of a radio resource in which downlink control information directed to another related terminal is arranged. In other words, the first sub information element D231 corresponds to the size information D102 illustrated in FIG. The second sub information element D232 corresponds to the start position information D101 illustrated in FIG. In the example of FIG. 11, the first information element D220 indicates the number of second information elements D230, D240, D250 stored in the reference information. Although the example of FIG. 11 illustrates three second information elements D230, D240, and D250 being stored, the first modification is not limited thereto. For example, the reference information according to the first modification may have one second information element.

<Modification 2> The reference information D10 illustrated in each of the embodiments and the modifications described above includes start position information D101 and size information D102. However, the reference information D10 in the present application is not limited to this. For example, the reference information D10 may include the start position information D101 but not include the size information D102. For example, in the wireless communication system 1 in which the size of the wireless resource to which the downlink control information for the second wireless terminal is allocated is defined as fixed, the size information D102 may be omitted. Thereby, the reference information can be further compressed. Such an action is further useful for realizing ultra-reliable low-latency communication while improving the transmission efficiency of information on interference components.

<Hardware Configuration> Finally, the hardware configuration of each apparatus used in the above-described first to third embodiments will be briefly described. FIG. 12 is a diagram showing an example of a hardware configuration of the wireless terminal 10 and the wireless base station 20 in the wireless communication system 1.

The wireless terminal 10 illustrated in FIG. 12 includes a wireless communication circuit 101, a processing circuit 102, and a memory 103. In the radio terminal 10 shown in FIG. 12, the illustration of the antenna is omitted. The wireless terminal 10 may also include a display device such as a liquid crystal display, an input device such as a touch panel, and a battery such as a lithium-ion rechargeable battery.

The wireless communication circuit 101 receives a baseband signal from the processing circuit 102 in the downlink (also referred to as downlink), generates a wireless signal of a predetermined output level from the baseband signal, and wirelessly transmits the signal via an antenna. It is configured to radiate a signal into space. In addition, in the uplink (also referred to as uplink), the wireless communication circuit 101 receives a wireless signal input from an antenna, converts the wireless signal into a baseband signal, and supplies the baseband signal to the processing circuit 102. Configured to The wireless communication circuit 101 can be communicably connected to the processing circuit 102 through a transmission circuit. As the transmission circuit, for example, a transmission circuit conforming to a standard such as M-PHY or Dig-RF can be mentioned. As described above, the wireless communication circuit 101 has an aspect as a communication unit (also referred to as a transmission / reception unit or a first transmission / reception unit) having a function of performing wireless communication with the wireless base station 20.

The processing circuit 102 is a circuit configured to perform baseband signal processing. The processing circuit 102 is configured to generate a baseband signal in the uplink based on the protocol stack in the wireless communication system and to output the baseband signal to the wireless communication circuit 101. In addition, the processing circuit 102 is configured to perform reception processing such as demodulation and decoding on the downlink based on a protocol stack in the wireless communication system with respect to a baseband signal input from the wireless communication circuit 101. In other words, in the uplink, the processing circuit 102 transmits from the upper layer to the lower layer toward the radio base station 20 as a receiving device according to the procedure of the protocol stack in which the function of wireless communication is divided into a plurality of layers. It has an aspect as a circuit that sequentially processes data and transmits it through the wireless communication circuit 101. Further, in the downlink, the processing circuit 102 sequentially processes radio signals received via the radio communication circuit 101 from the lower layer to the upper layer in accordance with the protocol stack procedure in which the function of radio communication is divided into a plurality of layers. Side as a circuit to be Here, in the downlink, receiving an input of a baseband signal from the wireless communication circuit 101 has an aspect of receiving a wireless signal from the wireless base station 20 via the wireless communication circuit 101.

The processing circuit 102 may be, for example, an arithmetic device that realizes the operation of the wireless terminal 10 according to the various embodiments described above by reading and executing a program stored in the memory 103. In other words, the processing circuit 102 has an aspect as an execution subject of the flow of processing in the wireless terminal 10 illustrated in FIG. Examples of the processing circuit 102 include a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), and a field programmable gate array (FPGA). The processing circuit 102 may be a multi-core processor including two or more cores. Also, the processing circuit 102 may implement two or more processing circuits 102 according to each layer in the protocol stack of the wireless communication system. For example, the processing circuit 102 that executes processing as a MAC entity belonging to the MAC (Medium Access Control) layer, the processing circuit 102 that executes processing as an RLC entity that belongs to the RLC (Radio Link Control) layer, and PDCP (Packet Data) The processing circuit 102 that executes processing as a PDCP entity belonging to the Convergence Protocol) layer may be implemented separately. The processing circuit 102 is also referred to as a C-CPU. The wireless terminal 10 may implement, in addition to the processing circuit 102, a processor circuit also referred to as an A-CPU that executes an application. Note that the processing circuit 102 may be mounted on one chip together with a processor circuit also referred to as an A-CPU, or may be mounted as an individual chip. The processing circuit 102 has an aspect as a control unit (also referred to as a first control unit) having a function of controlling the operation of the wireless terminal 10.

The memory 103 is a circuit configured to store and hold data and programs related to baseband signal processing executed by the processing circuit 102. The memory 103 is configured to include at least one or both of a non-volatile storage device and a volatile storage device. For example, RAM (Random Access Memory), ROM (Read Only Memory), SSD (Solid State Drive), HDD (Hard Disk Drive), etc. may be mentioned. In FIG. 12, a memory 103 is a generic term for various storage devices such as a main storage device and an auxiliary storage device. As in the processing circuit 102, two or more memories 103 may be mounted in the memory 103 in accordance with each layer in the protocol stack of the wireless communication system. For example, a memory 103 used for processing as a MAC entity belonging to the MAC layer, a memory 103 used for processing as an RLC entity belonging to the RLC layer, and a memory 103 used for processing as a PDCP entity belonging to the PDCP layer , May be implemented separately.

The wireless base station 20 illustrated in FIG. 12 includes a wireless communication circuit 201, a processing circuit 202, a memory 203, and a wired communication circuit 204. In the radio base station 20 shown in FIG. 12, the illustration of the antenna is omitted.

The wireless communication circuit 201 receives a baseband signal from the processing circuit 202 in the downlink, generates a wireless signal of a predetermined output level from the baseband signal, and radiates the wireless signal into space via an antenna. Configured Further, the wireless communication circuit 201 is configured to receive a wireless signal input from an antenna, convert the wireless signal into a baseband signal, and supply the baseband signal to the processing circuit 202 in the uplink. The wireless communication circuit 201 can also be communicably connected to the processing circuit 202 via a transmission path such as CPRI (Common Public Radio Interface), and is also referred to as RRH (Remote Radio Head) or RRE (Remote Radio Equipment). It can be done. Further, the combination of the wireless communication circuit 201 and the processing circuit 202 is not limited to one-to-one, and one wireless communication circuit 201 may be associated with a plurality of processing circuits 202 or a plurality of wireless communication circuits 201 may be combined. It is also possible to associate one processing circuit 202 or associate a plurality of wireless communication circuits 201 with a plurality of processing circuits 202. As described above, the wireless communication circuit 201 has an aspect as a communication unit (also referred to as a transmission / reception unit or a second transmission / reception unit) having a function of performing wireless communication with the wireless terminal 10.

The processing circuit 202 is a circuit configured to perform baseband signal processing. The processing circuit 202 is configured to generate a baseband signal in the downlink based on the protocol stack in the wireless communication system and to output the baseband signal to the wireless communication circuit 201. In addition, the processing circuit 202 is configured to perform reception processing such as demodulation and decoding on the uplink based on the protocol stack in the wireless communication system, on the baseband signal input from the wireless communication circuit 201. In other words, in the downlink, the processing circuit 202 transmits the transmission data for the radio terminal 10 as the receiving device from the upper layer to the lower layer in accordance with the protocol stack procedure in which the function of wireless communication is divided into a plurality of layers. It has an aspect as a circuit that sequentially processes and transmits via the wireless communication circuit 201. Further, in the uplink, the processing circuit 202 sequentially processes radio signals received via the wireless communication circuit 201 from the lower layer to the upper layer in accordance with the protocol stack procedure in which the function of wireless communication is divided into a plurality of layers. Side as a circuit to be Here, receiving an input of a baseband signal from the wireless communication circuit 201 in the uplink has an aspect of receiving a wireless signal from the wireless terminal 10 via the wireless communication circuit 201.

The processing circuit 202 may be, for example, an arithmetic unit that implements the operation of the radio base station 20 according to the various embodiments described above by reading and executing a program stored in the memory 203. In other words, the processing circuit 202 has an aspect as an execution subject of the processing flow in the radio base station 20 illustrated in FIG. 8. Examples of the processing circuit 202 include a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), and a field programmable gate array (FPGA). The processing circuit 202 may be a multi-core processor including two or more cores. Also, the processing circuitry 202 may implement more than one processing circuitry 202 depending on each layer in the protocol stack of the wireless communication system. For example, the processing circuit 202 that performs processing as a MAC entity that belongs to the MAC layer, the processing circuit 202 that performs processing as an RLC entity that belongs to the RLC layer, and the processing circuit that performs processing as a PDCP entity that belongs to the PDCP layer 202 may be implemented separately. As described above, the processing circuit 202 has an aspect as a control unit (also referred to as a second control unit) having a function of controlling the operation of the radio base station 20.

The memory 203 is a circuit configured to store and hold data and programs related to baseband signal processing executed by the processing circuit 202. The memory 203 is configured to include at least one or both of a non-volatile storage device and a volatile storage device. For example, RAM (Random Access Memory), ROM (Read Only Memory), SSD (Solid State Drive), HDD (Hard Disk Drive), etc. may be mentioned. In FIG. 12, a memory 203 is a generic term for various storage devices such as a main storage device and an auxiliary storage device. Note that, as with the processing circuit 202, two or more memories 203 may be mounted in the memory 203 in accordance with each layer in the protocol stack of the wireless communication system. For example, a memory 203 used for processing as a MAC entity belonging to the MAC layer, a memory 203 used for processing as an RLC entity belonging to the RLC layer, and a memory 203 used for processing as a PDCP entity belonging to the PDCP layer , May be implemented separately.

The wired communication circuit 204 converts it into packet data of a format that can be output to another device and transmits it to the other device, or extracts data etc. from packet data received from the other device, and the memory 203 or processing circuit Output to 202 or the like. Examples of other devices may include other wireless base stations, MME (Mobility Management Entity), SGW (Serving Gateway), and the like. The MME and SGW are also referred to as core nodes, and the logical communication interface used to communicate with the core nodes is also referred to as an S1 interface. The logical communication interface used to communicate with other wireless base station devices is also referred to as an X2 interface.

The features and advantages of the embodiments will be apparent from the foregoing detailed description. This is intended to cover the features and advantages of the embodiments as described above without departing from the spirit and scope of the claims. Also, all modifications and variations should be readily apparent to those skilled in the art. Accordingly, there is no intention to limit the scope of the inventive embodiments to those described above, and it is also possible to rely on appropriate modifications and equivalents included in the scope disclosed in the embodiments. For example, each step disclosed in the present specification does not necessarily have to be processed in chronological order according to the order described as an example of the processing flow, and is within the scope of the present invention described in the claims. The order of steps may be changed, or a plurality of steps may be performed in parallel. In addition, the circumstances that may occur in the fifth generation mobile communication system revealed in the above detailed description can be found when the fifth generation mobile communication system is considered from one aspect, and the other aspects are considered. It should be noted that in other cases other circumstances may be found. In other words, the features and advantages of the present invention are not limited to the application for solving the problems specified in the above detailed description.

Finally, the configuration of the embodiment of the present disclosure shows an example for embodying the technical idea of the present invention, and is not intended to limit the present invention to the configuration of this embodiment. The present invention is equally applicable to the other embodiments included in the claims. For example, it should be noted that the terms in the present disclosure may be renamed in the future specification of the fifth generation mobile communication system.

DESCRIPTION OF SYMBOLS 1 wireless communication system 10 wireless terminal 101 wireless communication circuit 102 processing circuit 103 memory 20 wireless base station 201 wireless communication circuit 202 processing circuit 203 memory 204 wired communication circuit 30 area

Claims (15)

  1. A wireless communication system capable of providing a wireless service by a non-orthogonal multiple access scheme, comprising:
    A wireless base station and a plurality of wireless terminals;
    The wireless base station is
    A process of selecting a first wireless terminal and a second wireless terminal for multiplexing downlink data signals on the same downlink radio resource by the non-orthogonal multiple access scheme among the plurality of radio terminals;
    The first downlink control information, which is downlink control information related to the first downlink data signal addressed to the first wireless terminal, and the second downlink control information related to the second downlink data signal addressed to the second wireless terminal A process of storing reference information indicating a position of a radio resource in which the downlink control information of
    Using a radio communication circuit, a downlink signal in which the first downlink control information, the second downlink control information, the first downlink data signal, and the second downlink data signal are arranged The process to send,
    With processing circuitry to perform
    The first wireless terminal is
    A process of acquiring first downlink control information addressed to the first wireless terminal from the downlink signal transmitted by the wireless base station;
    A process of acquiring the second downlink control information addressed to the second wireless terminal based on the reference information acquired from the first downlink control information;
    A process of receiving the second downlink data signal addressed to the second wireless terminal based on the second downlink control information;
    A process of removing an interference component due to the second downlink data signal from the downlink signal;
    A process of receiving the first downlink data signal addressed to the first wireless terminal based on the first downlink control information from the downlink signal after removal of the interference component;
    With processing circuitry to perform
    A wireless communication system characterized in that.
  2. The wireless communication system according to claim 1,
    The downlink signal has a plurality of radio resources defined at least on a frequency axis and a time axis,
    Among the plurality of radio resources, a control area is formed by a set of radio resources located forward in the time axis, and a data area is formed by a set of radio resources located behind the control area in the time axis. Yes,
    Each of the radio resources in the control area is distinguishable by a resource number assigned to the radio resource in the control area,
    The reference information includes the resource number corresponding to one radio resource among the one or more radio resources in which the second downlink control information is arranged in the control area, and the second downlink control information And the number of connections indicating the number of radio resources,
    The processing circuit of the first wireless terminal obtains the second downlink control information addressed to the second wireless terminal based on the resource number obtained from the reference information and the connection number.
    A wireless communication system characterized in that.
  3. The wireless communication system according to claim 1 or 2,
    The processing circuit of the wireless base station adds an error detection code capable of detecting an error of the second downlink control information to the reference information stored in the first downlink control information;
    The processing circuit of the first wireless terminal uses the error detection code included in the reference information acquired from the first downlink control information to acquire the second downlink control acquired based on the reference information. Perform error detection of information,
    A wireless communication system characterized in that.
  4. The wireless communication system according to claim 3,
    The error detection code is generated based on a parameter related to reception of the second downlink data signal addressed to the second wireless terminal in the second downlink control information,
    The first wireless terminal performs error detection of a parameter related to reception of the second downlink data signal in the second downlink control information using the error detection code acquired from the reference information.
    A wireless communication system characterized in that.
  5. The wireless communication system according to any one of claims 1 to 4, wherein
    The first wireless terminal is a wireless terminal having a higher SN ratio than the second wireless terminal.
    A wireless communication system characterized in that.
  6. A wireless base station capable of communicating with a plurality of wireless terminals by a non-orthogonal multiple access scheme,
    A process of selecting a first wireless terminal and a second wireless terminal for multiplexing downlink data signals on the same downlink radio resource by the non-orthogonal multiple access scheme among the plurality of radio terminals;
    The first downlink control information, which is downlink control information related to the first downlink data signal addressed to the first wireless terminal, and the second downlink control information related to the second downlink data signal addressed to the second wireless terminal A process of storing reference information indicating a position of a radio resource in which the downlink control information of
    Using a radio communication circuit, a downlink signal in which the first downlink control information, the second downlink control information, the first downlink data signal, and the second downlink data signal are arranged The process to send,
    With processing circuitry to perform
    A wireless base station characterized by
  7. The radio base station according to claim 6, wherein
    The downlink signal has a plurality of radio resources defined at least on a frequency axis and a time axis,
    Among the plurality of radio resources, a control area is formed by a set of radio resources located forward in the time axis, and a data area is formed by a set of radio resources located behind the control area in the time axis. Yes,
    Each of the radio resources in the control area is distinguishable by a resource number assigned to the radio resource in the control area,
    The reference information includes the resource number corresponding to one radio resource among the one or more radio resources in which the second downlink control information is arranged in the control area, and the second downlink control information And a connected number indicating the number of wireless resources,
    A wireless base station characterized by
  8. The radio base station according to claim 6 or 7,
    The processing circuit adds an error detection code capable of detecting an error in the second downlink control information to the reference information stored in the first downlink control information.
    A wireless base station characterized by
  9. The radio base station according to claim 8, wherein
    The error detection code is generated based on a parameter related to the reception of the second downlink data signal addressed to the second wireless terminal in the second downlink control information.
    A wireless base station characterized by
  10. The radio base station according to any one of claims 6 to 9, wherein
    The first wireless terminal is a wireless terminal having a higher SN ratio than the second wireless terminal.
    A wireless base station characterized by
  11. A first wireless terminal among a plurality of wireless terminals capable of communicating with a wireless base station by a non-orthogonal multiple access scheme,
    A process of acquiring, from the downlink signal transmitted by the wireless base station, first downlink control information which is downlink control information related to a first downlink data signal addressed to the first wireless terminal;
    From the first downlink control information, downlink control information on a second downlink data signal addressed to a second wireless terminal that is another wireless terminal other than the first wireless terminal among the plurality of wireless terminals A process of acquiring reference information indicating a position of a radio resource in which the second downlink control information is arranged;
    A process of acquiring the second downlink control information related to the second downlink data signal addressed to the second wireless terminal based on the reference information;
    A process of receiving the second downlink data signal addressed to the second wireless terminal based on the second downlink control information;
    A process of removing an interference component due to the second downlink data signal from the downlink signal;
    A process of receiving the first downlink data signal addressed to the first wireless terminal based on the first downlink control information from the downlink signal after removal of the interference component;
    With processing circuitry to perform
    A first wireless terminal characterized in that.
  12. The first wireless terminal according to claim 11, wherein
    The downlink signal has a plurality of radio resources defined at least on a frequency axis and a time axis,
    Among the plurality of radio resources, a control area is formed by a set of radio resources located forward in the time axis, and a data area is formed by a set of radio resources located behind the control area in the time axis. Yes,
    Each of the radio resources in the control area is distinguishable by a resource number assigned to the radio resource in the control area,
    The reference information includes the resource number corresponding to one radio resource among the one or more radio resources in which the second downlink control information is arranged in the control area, and the second downlink control information And the number of connections indicating the number of radio resources,
    The processing circuit of the first radio terminal acquires the second downlink control information addressed to the second radio terminal based on the resource number acquired from the reference information and the number of radio resources. ,
    A first wireless terminal characterized in that.
  13. A first wireless terminal according to claim 11 or 12,
    The processing circuit of the wireless base station adds an error detection code capable of detecting an error of the second downlink control information to the reference information stored in the first downlink control information;
    The processing circuit of the first wireless terminal uses the error detection code included in the reference information acquired from the first downlink control information to acquire the second downlink control acquired based on the reference information. Perform error detection of information,
    A first wireless terminal characterized in that.
  14. The first wireless terminal according to claim 13, wherein
    The error detection code is generated based on a parameter related to reception of the second downlink data signal addressed to the second wireless terminal in the second downlink control information,
    The first wireless terminal performs error detection of a parameter related to reception of the second downlink data signal in the second downlink control information using the error detection code acquired from the reference information.
    A first wireless terminal characterized in that.
  15. A first wireless terminal according to any of claims 11 to 14, wherein
    The first wireless terminal is a wireless terminal having a higher SN ratio than the second wireless terminal.
    A first wireless terminal characterized in that.
PCT/JP2017/023203 2017-06-23 2017-06-23 Wireless communication system enabling non-orthogonal multiple access, wireless communication base station, and wireless terminal WO2018235263A1 (en)

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JP2015041941A (en) * 2013-08-23 2015-03-02 株式会社Nttドコモ Wireless base station, relay station and wireless communication method
JP2016187118A (en) * 2015-03-27 2016-10-27 Kddi株式会社 Base station device, terminal device, communication method, and communication system
JP2017513384A (en) * 2014-04-02 2017-05-25 エルジー エレクトロニクス インコーポレイティド Method and apparatus for transmitting and receiving signals in a wireless communication system

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Publication number Priority date Publication date Assignee Title
JP2015041941A (en) * 2013-08-23 2015-03-02 株式会社Nttドコモ Wireless base station, relay station and wireless communication method
JP2017513384A (en) * 2014-04-02 2017-05-25 エルジー エレクトロニクス インコーポレイティド Method and apparatus for transmitting and receiving signals in a wireless communication system
JP2016187118A (en) * 2015-03-27 2016-10-27 Kddi株式会社 Base station device, terminal device, communication method, and communication system

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