Base station, terminal, and communication method

Abstract

A base station, a terminal, and a communication method are described. The present disclosure includes a base station comprising: a circuit configured to set a control resource set (CORESET) in a physical downlink control channel (PDCCH) including control channel elements (CCEs); and a transmitter configured to transmit a downlink control signal in the CORESET, wherein the CCEs are formed by six resource element groups (REGs) in the CORESET, the six REGs are bundled into a REG bundle, and the REG bundle size of the REG bundle varies depending on the number of symbols in the CORESET.

Description

[0001] This application is a divisional application of the Chinese invention patent application with the application date of January 19, 2018, application number 201880015822.3, invention name “Base station, terminal and communication method”, and applicant being Panasonic Electric (USA) Intellectual Property Corporation. Technical Field

[0002] The present invention relates to a base station, a terminal and a communication method. Background Art

[0003] Research is underway on a communication system called the fifth generation mobile communication system (5G). In 5G, research is underway to flexibly provide functions for each use case that requires an increase in communication traffic volume, an increase in the number of connected terminals, high reliability, and low latency. There are three representative use cases, namely, extended mobile broadband (eMBB), massive Machin Type Communications (mMTC), and ultra-reliable and low-latency communications (URLLC). In the international standardization organization 3GPP (3rd Generation Partnership Project), research is underway on improving the communication system from two aspects: improving the LTE system and new RAT (Radio Access Technology) (for example, refer to non-patent document 1).

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-Patent Document 1: RP-161596, “Revision of SI: Study on New Radio Access Technology”, NTT DOCOMO, September 2016

[0007] Non-Patent Document 2: R1-1702765, "DL control channel design", Panasonic, February 2017 Summary of the Invention

[0008] In the new RAT, the configuration of multiple control resource sets (hereinafter referred to as "CORESETs") for terminals (UEs) is being studied as a region where a control signal channel including a DCI (Downlink Control Indicator) is allocated. However, in the new RAT, the configuration method of the CCEs (Control Channel Elements) that constitute the search space within the CORESETs has not been fully studied.

[0009] One embodiment of the present invention contributes to providing a base station, a terminal, and a communication method that appropriately arrange CCEs constituting a search space in a CORESET.

[0010] A base station of one embodiment of the present invention includes: a circuit that allocates a downlink control signal to a control channel area composed of multiple control channel elements (CCE); and a transmitter that sends the downlink control signal, where the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0011] A terminal of one embodiment of the present invention includes: a receiver that receives a downlink control signal in a control channel area composed of multiple control channel elements (CCE); and a circuit that decodes the downlink control signal, wherein the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs among the REGs constituting the CCE and configured in adjacent resource blocks is a power of 2.

[0012] A communication method according to one embodiment of the present invention includes the following steps: allocating a downlink control signal to a control channel area composed of a plurality of control channel elements (CCE), sending the downlink control signal, wherein the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0013] A communication method according to one embodiment of the present invention includes the following steps: receiving a downlink control signal in a control channel area composed of a plurality of control channel elements (CCE), decoding the downlink control signal, wherein the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0014] A base station of one embodiment of the present invention includes: a circuit that sets a control resource set CORESET in a physical downlink control channel PDCCH including a control channel element CCE; and a transmitter that sends a downlink control signal in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and the REG bundle size of the REG bundle varies according to the number of code elements of the CORESET.

[0015] A communication method according to one embodiment of the present invention includes the following steps: setting a control resource set CORESET in a physical downlink control channel PDCCH including a control channel element CCE; and sending a downlink control signal in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and the REG bundle size of the REG bundle is different according to the number of code elements of the CORESET.

[0016] An integrated circuit for a base station according to one embodiment of the present invention includes: a controller circuit that controls: setting a control resource set CORESET in a physical downlink control channel PDCCH including a control channel element CCE; and sending a downlink control signal in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and the REG bundle size of the REG bundle is different according to the number of code elements of the CORESET.

[0017] Furthermore, these general or specific methods can be implemented as systems, devices, methods, integrated circuits, computer programs, or storage media, or can be implemented by any combination of systems, devices, methods, integrated circuits, computer programs and storage media.

[0018] Effects of the Invention

[0019] According to one embodiment of the present invention, CCEs constituting a CORESET can be appropriately arranged.

[0020] Further advantages and effects of one embodiment of the present invention will be apparent from the description and accompanying drawings. These advantages and / or effects may be provided separately by the features described in several embodiments and the description and accompanying drawings, and it is not necessary to provide all features in order to obtain one or more of the same features. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A It shows an example of REG mapping (Frequency first mapping).

[0022] Figure 1B This shows a mapping example of REG (Frequency first mapping).

[0023] Figure 1C It shows an example of REG mapping (time first mapping).

[0024] Figure 1D This shows an example of REG mapping (Time first mapping).

[0025] Figure 2A This shows an example of REG bundling.

[0026] Figure 2B This shows an example of REG bundling.

[0027] Figure 2C This shows an example of REG bundling.

[0028] Figure 3 An example of REG mapping is shown when the number of REGs per CCE is 4, the number of symbols is 3, and the REG bundling size is 2.

[0029] Figure 4 This shows an example of the number of REGs constituting the same DCI per symbol per aggregation level.

[0030] Figure 5 A partial configuration of a base station according to the first embodiment is shown.

[0031] Figure 6 A partial configuration of a terminal according to the first embodiment is shown.

[0032] Figure 7 The structure of the base station according to the first embodiment is shown.

[0033] Figure 8 The structure of the terminal according to the first embodiment is shown.

[0034] Figure 9 An example of operations of the base station and the terminal according to the first embodiment is shown.

[0035] Figure 10A An example of REG mapping in operation example 1-1 of embodiment 1 is shown (a case where the number of symbols is 1).

[0036] Figure 10B An example of REG mapping in operation example 1-1 of embodiment 1 is shown (a case where the number of symbols is 2).

[0037] Figure 10C An example of REG mapping in operation example 1-1 of Embodiment 1 is shown (a case where the number of symbols is 4).

[0038] Figure 11 An example of the number of REGs constituting the same DCI per symbol per aggregation level in operation example 1-1 of the first embodiment is shown.

[0039] Figure 12 An example of the number of REGs constituting the same DCI per symbol per aggregation level in operation example 1-1 of the first embodiment is shown.

[0040] Figure 13 A mapping example of the constituent REGs of Operation Example 1-2 of the first embodiment is shown.

[0041] Figure 14 An example of the number of REGs constituting the same DCI per symbol per aggregation level in operation example 1-2 of embodiment 1 is shown.

[0042] Figure 15 An example of DMRS mapping in operation example 1-3 of embodiment 1 is shown (a case where the number of symbols is 2).

[0043] Figure 16A An example of DMRS mapping in operation example 1-3 of embodiment 1 is shown (a case where the number of symbols is 4).

[0044] Figure 16B An example of DMRS mapping in operation example 1-3 of embodiment 1 is shown (a case where the number of symbols is 4).

[0045] Figure 17A An example of REG mapping according to the second embodiment is shown (when the number of symbols is 2).

[0046] Figure 17B An example of REG mapping according to the second embodiment (a case where the number of symbols is 4) is shown.

[0047] Figure 17C An example of REG mapping according to the second embodiment (a case where the number of symbols is 3) is shown.

[0048] Figure 17D An example of REG mapping according to the second embodiment is shown (when the number of symbols is 6).

[0049] Figure 18 An example of the number of REGs constituting the same DCI per symbol per aggregation level according to the second embodiment is shown (a case where the number of symbols is 2).

[0050] Figure 19An example of the number of REGs constituting the same DCI per symbol per aggregation level according to the second embodiment is shown (a case where the number of symbols is 4).

[0051] Figure 20 An example of the number of REGs constituting the same DCI per symbol per aggregation level according to the second embodiment is shown (a case where the number of symbols is 3).

[0052] Figure 21 An example of the number of REGs constituting the same DCI per symbol per aggregation level according to the second embodiment is shown (a case where the number of symbols is 6). DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0054] As mentioned above, in the new RAT, the CORESET, which serves as the control channel area containing control signals (DCI), is configured in the UE. The UE monitors (blindly decodes) the search space within the configured CORESET to detect DCI addressed to it. Furthermore, the study is defining the search space where DCI is allocated using CCEs.

[0055] Here, in the new RAT, the number of REGs (Resource Element Groups) per CCE is considered to be between 4 and 8. Also, the number of symbols configured with CORESET ranges from 1 symbol to all symbols within a slot or subframe.

[0056] However, due to the combination of the number of REGs per CCE and the number of symbols in the configured CORESET, the number of REGs per symbol in each CCE may be uneven. If the number of REGs between symbols in a CCE is uneven, the received SINR (Signal to Interference and Noise Ratio) per symbol will vary, making it difficult to adjust power between CCEs.

[0057] The following describes this in more detail.

[0058] DCI is transmitted by one or more CCEs. Here, the number of CCEs used for one DCI is called the "aggregation level." In other words, the aggregation level indicates the amount of resources used to transmit DCI. When DCI is transmitted by a CORESET (PDCCH region), for example, in aggregation level 1, DCI is transmitted by one CCE, and in aggregation level 2, DCI is transmitted by two CCEs.

[0059] Furthermore, as one method of forming a plurality of REGs of a CCE, a method of setting one symbol within one PRB (Physical Resource Block) as a "REG" is under study (for example, see Figure 1A ).

[0060] In the case of such a method, as the structure of CCE, consider the following Figure 1A and Figure 1B As shown, the case where CCE (sometimes also expressed as NR-CCE) is composed of REGs configured in the same codeword, and Figure 1C and Figure 1D As shown, a CCE is constituted by REGs arranged in a plurality of symbols.

[0061] The case where the REGs constituting 1CCE are arranged in the same codeword is called "frequency-first mapping". Frequency-first mapping has advantages such as reducing the number of codewords occupied by CCE and increasing the amount of resources allocated to PDSCH (Physical Downlink Shared Channel). On the other hand, the case where the REGs constituting 1CCE are arranged in multiple codewords is called "time-first mapping". When there is a limit on the transmit power that can be used for each codeword, time-first mapping has advantages such as being able to increase the transmit power because CCE can be transmitted using multiple codewords (for example, refer to non-patent document 2).

[0062] Furthermore, new RATs are also investigating a method called "REG bundling." REG bundling involves placing multiple REGs that make up the same CCE in adjacent PRBs, sharing the reference signal (DMRS: Demodulation Reference Signal) in those adjacent PRBs between the REGs to improve channel estimation accuracy.

[0063] Figures 2A to 2C : This shows an example of mapping (configuration example) of REGs when the number of REGs configured in adjacent PRBs, that is, the number of bundles (hereinafter referred to as "REG bundle size") is set to 2. Figures 2A to 2C As shown, two REGs constituting the same CCE are arranged in adjacent PRBs. Thus, even when multiple DMRSs are not arranged in the time direction (symbol direction), channel estimation can be interpolated in the frequency direction, thereby improving channel estimation accuracy.

[0064] Here, when the number of REGs per CCE is set to 4 or 8 and the number of symbols in CORESET is set to 3, it is difficult to evenly arrange the REGs per CCE in 3 symbols. Figure 3 An example of REG mapping is shown when the number of REGs per CCE is set to 4, the number of symbols in CORESET is set to 3, and the REG bundling size is set to 2. Figure 4 express Figure 3 In the REG mapping example shown, the number of REGs constituting the same DCI for each symbol per aggregation level (sometimes also expressed as AL) is shown.

[0065] For example, in Figure 3 In the case of medium aggregation level 1 (AL1), that is, when the number of REGs to which DCI is allocated is 4, 2 REGs are allocated in 2 symbols among 3 symbols, and no REG is allocated in the remaining 1 symbol. Figure 3 In the case of medium aggregation level 2 (AL2), that is, when the number of REGs to which DCI is allocated is 8, among 3 symbols, in 1 symbol ( Figure 3 In the example of symbol #0), 4 REGs are configured, and the remaining 2 symbols ( Figure 3 In the example of , two REGs are allocated to symbols #1 and #2 respectively. The same applies to aggregation levels 4 and 8 (AL4 and AL8).

[0066] That is, Figure 4 As shown, in AL1, the REGs constituting 1CCE for DCI transmission are arranged only in 2 symbols and not in 1 symbol. Figure 4 As shown, in AL2, AL4, and AL8, the REGs that make up the multiple CCEs used for DCI transmission are unevenly distributed across symbols. Consequently, the number of REGs varies across symbols in one or more CCEs used for DCI transmission, resulting in variations in the received SINR for each symbol and making it difficult to adjust power across CCEs.

[0067] Therefore, the following describes a method for facilitating power adjustment between CCEs by uniformly arranging REGs constituting a plurality of CCEs used for DCI transmission between symbols to suppress dispersion in received SINR per symbol.

[0068] (Implementation 1)

[0069] [Overview of the Communication System]

[0070] The communication system according to each embodiment of the present invention includes a base station 100 and a terminal 200 (UE).

[0071] Figure 5 1 is a block diagram showing a part of the configuration of the base station 100 according to the embodiment of the present invention. Figure 5In the illustrated base station 100, a signal allocating unit 105 allocates a downlink control signal (DCI) to a control channel region (CORESET) composed of a plurality of control channel elements (CCEs). A transmitting unit 106 transmits the downlink control signal.

[0072] Figure 6 2 is a block diagram showing a part of the structure of the terminal 200 according to the embodiment of the present invention. Figure 6 In the terminal 200 shown, a receiver 201 receives a downlink control signal (DCI) in a control channel region (CORESET) composed of a plurality of control channel elements (CCEs). A DCI receiver 203 decodes the downlink control signal (blind decoding).

[0073] Here, the number of resource element groups (REGs) constituting a CCE is a power of 2, which means that the bundling size of the number of REGs arranged in adjacent resource blocks among the REGs constituting a CCE is a power of 2.

[0074] [Structure of base station]

[0075] Figure 7 is a block diagram showing the configuration of the base station 100 according to this embodiment. Figure 7 In the present invention, base station 100 includes CORESET setting section 101, DCI generating section 102, error correction coding section 103, modulation section 104, signal allocation section 105, transmission section 106, reception section 107, signal separation section 108, demodulation section 109, and error correction decoding section 110.

[0076] CORESET configuration section 101 configures a CORESET for each terminal 200 (UE). CORESET configuration (definition) includes, for example, the number of PRBs, PRB numbers, symbol numbers, symbol numbers, scrambling IDs used for the CORESET, the mapping method (localized or distributed) for each CORESET, and Quasi Collocation (QCL). CORESET configuration section 101 generates upper-layer signaling (e.g., SIB (System Information Block) or specific RRC (Radio Resource Control)) including CORESET configuration information indicating the CORESET configuration. CORESET configuration section 101 outputs the upper-layer signaling to error correction coding section 103 and outputs the CORESET configuration information to signal allocation section 105.

[0077] The DCI generation unit 102 generates DCI including resource allocation information (DL allocation information or UL allocation information) for a DL (Downlink) data signal or a UL (Uplink) data signal, and outputs the DCI to the signal allocation unit 105. Furthermore, the DCI generation unit 102 outputs the DL allocation information of the generated DCI to the signal allocation unit 105 and the UL allocation information to the signal separation unit 108.

[0078] Error correction coding section 103 performs error correction coding on the transmission data signal (DL data signal) and upper layer signaling (CORESET setting information) input from CORESET setting section 101 , and outputs the coded signal to modulation section 104 .

[0079] Modulation section 104 modulates the signal received from error correction coding section 103 and outputs the modulated signal to signal distribution section 105 .

[0080] Signal allocation section 105 allocates the signals (DL data signals, upper layer signaling) received from modulation section 104 to downlink resources based on the DL allocation information input from DCI generation section 102. Furthermore, signal allocation section 105 allocates the DCI input from DCI generation section 102 to resources (one or more CCEs within a CORESET) based on the CORESET configuration information input from DCI generation section 102. For example, signal allocation section 105 may change the mapping of REGs or the mapping of search spaces to CCEs based on the number of symbols in the CORESET configured as indicated in the CORESET configuration information. This generates a transmit signal, which is output to transmission section 106.

[0081] Transmitting section 106 performs radio transmission processing such as up-conversion on the transmission signal input from signal distribution section 105 , and transmits the signal to terminal 200 via the antenna.

[0082] Receiving section 107 receives a signal transmitted from terminal 200 via an antenna, performs wireless reception processing such as down-conversion on the received signal, and outputs the signal to signal separating section 108 .

[0083] Signal separation section 108 separates the UL data signal from the reception signal received by reception section 106 based on the UL allocation information input from DCI generation section 102 , and outputs the separated signal to demodulation section 109 .

[0084] Demodulation section 109 performs demodulation processing on the signal input from signal separation section 108 , and outputs the obtained signal to error correction decoding section 110 .

[0085] Error correction decoding section 110 decodes the signal input from demodulation section 109 to obtain a received data signal (UL data signal) from terminal 200 .

[0086] [Structure of the terminal]

[0087] Figure 8 is a block diagram showing the structure of the terminal 200 according to this embodiment. Figure 8 In the embodiment, terminal 200 includes a receiving unit 201, a signal separation unit 202, a DCI receiving unit 203, a demodulation unit 204, an error correction decoding unit 205, a setting information receiving unit 206, an error correction coding unit 207, a modulation unit 208, a signal allocation unit 209, and a transmission unit 210.

[0088] The receiving unit 201 receives the received signal via the antenna, performs reception processing such as down-conversion on the received signal, and then outputs it to the signal separation unit 202. The received signal includes, for example, DL data signals, higher layer signaling (including CORESET configuration information), or DCI (including resource allocation information, etc.).

[0089] The signal separation unit 202 separates the uplink signal from the received signal and outputs it to the demodulation unit 204. Furthermore, based on the information indicating the CORESET configuration input from the configuration information reception unit 206, the signal separation unit 202 identifies the resource corresponding to the CORESET to be monitored by the receiving unit (the CORESET to be separated) from the received signal received from the reception unit 201, separates the signal allocated in the resource, and outputs it to the DCI reception unit 203. Furthermore, based on the DL allocation information input from the DCI reception unit 203, the signal separation unit 202 separates the DL data signal from the received signal and outputs it to the demodulation unit 204.

[0090] DCI receiving section 203 attempts to decode the signal allocated to the resources corresponding to the CORESET, input from signal demultiplexing section 202, and detects (receives) DCI addressed to itself. DCI receiving section 203 outputs the UL allocation information indicated in the received DCI to signal allocation section 209 and outputs the DL allocation information to signal demultiplexing section 202.

[0091] Demodulation section 204 demodulates the signal input from signal separation section 202 , and outputs the demodulated signal to error correction decoding section 205 .

[0092] Error correction decoding section 205 decodes the demodulated signal received from demodulation section 204 , outputs the obtained received data signal, and outputs the obtained upper layer signaling to configuration information receiving section 206 .

[0093] Configuration information receiving section 206 determines the CORESET configuration for each terminal 200 based on the CORESET configuration information included in the upper layer signaling output from error correction decoding section 205 . Configuration information receiving section 206 then outputs the determined information to signal demultiplexing section 202 .

[0094] Error correction coding section 207 performs error correction coding on the transmission data signal (UL data signal) and outputs the coded data signal to modulation section 208 .

[0095] Modulation section 208 modulates the data signal input from error correction coding section 207 and outputs the modulated data signal to signal distribution section 209 .

[0096] Signal allocating section 209 determines the resources to which data is allocated based on the UL allocation information input from DCI receiving section 203 . Signal allocating section 209 then allocates the data signal input from modulating section 209 to the determined resources and outputs the result to transmitting section 210 .

[0097] Transmitting section 210 performs transmission processing such as up-conversion on the signal input from signal distribution section 209 and transmits the signal via an antenna.

[0098] [Operations of Base Station 100 and Terminal 200]

[0099] The operations in base station 100 and terminal 200 having the above configurations will be described in detail.

[0100] Figure 9 It is a sequence diagram showing the operations of the base station 100 and the terminal 200 .

[0101] Base station 100 configures a CORESET for each terminal 200 (ST101). Base station 100 transmits the configured CORESET configuration information to terminal 200 using upper layer signaling (ST102). Next, base station 100 generates DCI containing resource allocation information, etc. (ST103). Base station 100 allocates the generated DCI to any search space within the CORESET configured in ST101 and transmits it to terminal 200 (ST104). Details of the mapping method (allocation method) for the CCEs (REGs) that constitute a CORESET will be described later.

[0102] On the other hand, terminal 200 monitors the CORESET (search space) based on the CORESET setting information included in the upper layer signaling received in ST102 and detects DCI addressed to the terminal itself ( ST105 ).

[0103] Next, the details of the mapping method of CCE (REG) constituting CORESET are described.

[0104] Hereinafter, operation examples 1-1 to 1-3 of this embodiment will be described respectively.

[0105] <Action Example 1-1>

[0106] In operation example 1-1, regarding mapping to CCEs and REGs of a CORESET, it is assumed that the number of REGs constituting a CCE (the number of REGs per CCE) is a power of 2, and the REG bundling size is a power of 2.

[0107] Furthermore, in Operation Example 1-1, it is assumed that the number of symbols for which CORESET is set is a power of 2.

[0108] With this configuration, even when the number of symbols of the CORESET configured in the terminal 200 is different, the mapping of REGs constituting the CCEs in the CORESET is common, and the mapping of REGs becomes simple.

[0109] Furthermore, by setting the REG bundling size to a power of 2, different subcarrier spacings (mathematically) are allocated in the same time slot, making adjustment easier when performing interference control between cells.

[0110] Figures 10A to 10C The number of REGs per CCE is 4 (=2 2 ), REG bundle size is 2 (=2 1 ) is an example of REG mapping.

[0111] exist Figures 10A to 10C In the example, it is assumed that the mapping of REGs is time-first mapping. That is, the REGs constituting one CCE are configured in the time direction (symbol) in units of REG bundle size rather than in the frequency direction (PRB). Figures 10A to 10C In the present embodiment, it is assumed that the mapping of the search space to the CCE is also time-first. That is, the base station 100 prioritizes the allocation of DCI in the time direction (symbol) over the frequency direction (PRB) per CCE. As a result, the REGs constituting the CCEs used for DCI transmission are allocated in symbols as different as possible, based on the REG bundling size.

[0112] Figure 10A The number of symbols representing CORESET is 1 (=2 0 ) in the case of REG mapping example.

[0113] like Figure 10AAs shown in FIG1 , when the number of symbols in a CORESET is 1, all REGs constituting a CCE are allocated in the same symbol (symbol #0) even in time-first mapping. Therefore, by limiting the number of symbols in a CORESET to 1, for example, even without separately defining frequency-first mapping, frequency-first mapping can be implemented with the same design as time-first mapping.

[0114] In particular, in high frequency bands, such as millimeter wave bands, it is considered to change the beam (precoding) for each symbol. In this case, the terminal 200 (UE) changes the beam (precoding) configured in 1 symbol by Figure 10A ) monitor multiple signals with different symbols, making time division multiplexing easier. Therefore, in high-frequency bands, it is also effective to limit the number of symbols in the CORESET to 1.

[0115] Figure 10B The number of symbols representing CORESET is 2 (=2 1 ) in the case of REG mapping example.

[0116] like Figure 10B As shown, when the number of symbols in the CORESET is 2, two REGs constituting the CCE are arranged in symbol #0, and the remaining two REGs are arranged in symbol #1. That is, two REGs constituting the CCE are arranged in two symbols, each in units of the REG bundling size.

[0117] Figure 10C The number of symbols representing CORESET is 4 (=2 2 ) in the case of REG mapping example.

[0118] like Figure 10C As shown, when the number of symbols in the CORESET is 4, the REGs constituting one CCE are respectively arranged in two symbols in units of the REG bundling size (2REG). In addition, for example, the REGs constituting two CCEs for transmitting DCI of aggregation level 2 are respectively arranged in four different symbols.

[0119] like Figure 10B and Figure 10C As shown, by arranging the REGs of each CCE, the REGs constituting one or more CCEs used for DCI transmission are evenly arranged for each symbol.

[0120] For example, Figure 11 This shows the case where the number of REGs per CCE is 4, the number of symbols is 2, and the number of REG bundles is 2 (for example, see Figure 10B An example of the number of REGs per symbol for each aggregation level (AL1, AL2, AL4, AL8). Figure 11As shown, it can be seen that the number of REG pairs per symbol constituting CCEs used to transmit the same DCI is the same at all aggregation levels.

[0121] also, Figure 12 This shows a case where the number of REGs per CCE is 4, the number of symbols is 4, and the number of REG bundles is 2 (for example, see Figure 10C ) is an example of the number of REGs per symbol per aggregation level. Figure 12 As shown in FIG. 1 , in AL1, 4 REGs constituting 1 CCE for DCI transmission are evenly allocated in 2 symbols. Figure 12 As shown, it can be seen that in AL2, AL4, and AL8, the number of REG pairs per symbol constituting CCEs used to transmit the same DCI is the same in all aggregation levels.

[0122] In this way, by arranging the power-of-two REGs constituting each CCE in a power-of-two symbol in units of the REG bundling size, the number of REGs constituting the CCE used for DCI transmission becomes uniform for each symbol, facilitating power adjustment between CCEs.

[0123] Furthermore, since the mapping of REGs and the mapping to the search space of CCEs are based on time-first mapping, PDCCH (DCI) is allocated to multiple symbols when the aggregation level is large, there is an advantage that power improvement becomes easy.

[0124] Furthermore, by setting the REG bundling size to a power of 2, even when there are terminals 200 with different subcarrier spacings, the PRB spacing in the frequency domain can be made uniform, thereby improving resource utilization efficiency.

[0125] <Action Examples 1-2>

[0126] Operation Example 1-1 describes a case where the number of symbols in the CORESET is a power of 2. In contrast, Operation Example 1-2 describes a case where the number of symbols in the CORESET is a value other than a power of 2.

[0127] For example, when the number of symbols of CORESET is a symbol number other than a power of 2, the mapping of REGs is set as a reference for mapping REGs with a symbol number that is larger than the number of symbols of CORESET and closest to a power of 2.

[0128] Specifically, when the number of code elements in CORESET is 3, Figure 13 As shown, the number of symbols described in the operation example 1-1 is 4 (=2 2 ) of the REG mapping (for example, refer to Figure 10C), the mapping of REGs in the codewords of CORESET is set by puncturing or rate matching the final codeword.

[0129] In this way, although the number of REGs actually used differs from the reference REG mapping, the number of REGs per symbol constituting CCEs used to transmit the same DCI becomes equal at aggregation levels 2, 4, and 8. Furthermore, since a common REG mapping design can be used for all symbols, there is an advantage such as a simplified design.

[0130] For example, Figure 14 It shows the number of REGs per symbol at each aggregation level when the number of REGs per CCE is 4, the number of symbols is 3, and the number of REG bundling is 2. Figure 14 The mapping based on REGs is shown when the number of REGs per CCE is 4, the number of symbols is 4, and the number of REG bundles is 2 (for example, refer to Figure 10C 、 Figure 12 ), the number of REGs per symbol when puncturing or rate matching is performed on the final symbol. Figure 14 As shown, it can be seen that in AL2, AL4, and AL8, the number of REG pairs per symbol constituting CCEs used to transmit the same DCI is equal in all aggregation levels.

[0131] In addition, if Figure 14 As shown, in AL1, the REG constituting one CCE used for DCI transmission may be allocated within two symbols or within one symbol. In AL1, when the number of REGs allocated is one symbol, that is, when the number of REGs is half of the typical number (4 REGs), it is considered that sufficiently good reception quality cannot be expected. Therefore, in AL1, terminal 200 may be limited to monitoring only CCEs allocated within two symbols.

[0132] Furthermore, in the case where the number of symbols in the CORESET is a number other than a power of 2, the case where symbols are punctured or rate matched is described using the mapping design of REGs in a number of symbols greater than the number of symbols in the CORESET as a reference. However, in the case where the number of symbols in the CORESET is a number other than a power of 2, symbols may be repeated using the mapping design of REGs in a number of symbols less than the number of symbols in the CORESET as a reference. For example, in the case where the number of symbols in the CORESET is 5, the mapping of REGs in the case where the number of symbols in the CORESET is 4 (for example, refer to Figure 10C ) as a benchmark, by repeating the final symbol (symbol #3) or the beginning symbol (symbol #0), the mapping of REG can also be set when the number of symbols is 5.

[0133] As described above, according to Operation Example 1-2, even when the number of symbols in a CORESET is a number other than a power of 2, the number of REGs constituting CCEs used for DCI transmission becomes uniform for each symbol, making power adjustment between CCEs easier.

[0134] Note that the operation example 1-2 is not limited to the case where the number of symbols in the CORESET is 3 or 5.

[0135] <Action Examples 1-3>

[0136] In operation example 1-3, in addition to operation example 1-1, REGs of the same CCE are bundled and arranged in the same PRB. That is, REGs constituting one CCE are arranged in multiple symbols of the same frequency in units of the REG bundling size.

[0137] In addition, at this time, the DMRS used for demodulation of the CCE is arranged in the first symbol among the multiple symbols in which the CCE is arranged, and is not arranged in the remaining symbols.

[0138] If this is done, the number of DMRSs can be reduced.

[0139] Figure 15 An example of mapping of DMRS and REG is shown when the number of COREST symbols is 2, the number of REGs per CCE is 4, and the REG bundling size is 2.

[0140] exist Figure 15 In the example, since the REG bundling size is 2, the REGs constituting the same CCE are arranged in two adjacent PRBs. In addition, the REGs constituting the same CCE are arranged in two symbols #0 and #1 of the same frequency (2PRBs) in units of the REG bundling size.

[0141] At this time, if Figure 15 As shown, DMRS constitutes CCE for transmitting the same DCI, and REGs arranged in the same frequency in units of REG bundling size are arranged in the first symbol #0 among the arranged symbols. Figure 15 As shown, DMRS is not allocated in symbol # 1. In this case, terminal 200 performs channel estimation in symbol # 1 using DMRS of symbol # 0 in which REGs constituting the same CCE are allocated.

[0142] then, Figure 16A and Figure 16B An example of mapping of DMRS and REGs is shown when the number of COREST symbols is 4, the number of REGs per CCE is 4, and the REG bundling size is 2.

[0143] exist Figure 16A and Figure 16B In, with Figure 15 Likewise, since the REG bundling size is 2, the REGs constituting the same CCE are arranged in two adjacent PRBs.

[0144] exist Figure 16A In the example, the REGs constituting the same CCE are configured in the same PRB (2PRB) in units of REG bundling.

[0145] At this time, DMRS constitutes CCEs used for transmitting the same DCI, and REGs arranged in the same frequency in units of the REG bundling size are arranged in the leading symbol among the arranged symbols.

[0146] For example, in Figure 16A In the case of aggregation level 2, the two CCEs used for transmitting the same DCI are allocated in the four symbols #0 to #3 of the same PRB (for example, refer to PRB #0, #1). In this case, in PRB #0, #1, DMRS is allocated in the first symbol #0 and is not allocated in the remaining symbols #1 to #3. Therefore, in the PRB ( Figure 16A In PRB #0, #1), in addition to symbol #1, terminal 200 can also use the DMRS of symbol #0 in demodulation in symbol #2 and symbol #3.

[0147] On the other hand, in the case of aggregation level 1, as Figure 16A Among the symbols of one CCE (REG) configured for the transmission of the same DCI, DMRS is configured in the first symbol ( Figure 16A That is, in the case of aggregation level 1, DMRS is arranged in the first symbol among the symbols in which REGs constituting each CCE are arranged.

[0148] In addition, Figure 16BIn the case of aggregation level 2, the two CCEs used for transmitting the same DCI are configured in different PRBs (for example, PRB#0, #1 and PRB#8, #9). In this case, for each frequency (2PRB) in which the REGs constituting these CCEs are configured in units of REG bundling size, the DMRS is respectively configured in the beginning codeword among the codewords configured with the REG. For example, in the case where the two CCEs used for transmitting the same DCI are CCEs in codewords #0, #1 configured in PRB#0, #1, and CCEs in codewords #2, #3 configured in PRB#8, #9, the DMRS is respectively configured in the beginning codewords #0, #2 among the codewords configured with the CCEs of PRB#0, #1 and PRB#8, #9. In this case, the terminal 200 is configured in the Figure 16B In the CCEs in codewords #0 and #1, channel estimation is performed using the DMRS configured in codeword #0, and in the CCEs configured in codewords #2 and #3, channel estimation is performed using the DMRS configured in codeword #2.

[0149] Thus, according to example 1-3, DMRSs are shared across CCEs allocated across multiple symbols within the same PRB. Specifically, by allocating DMRSs in the leading symbol and omitting them in the remaining symbols, the number of DMRSs can be reduced. Furthermore, terminal 200 can use the DMRSs allocated in the leading symbol to pre-demodulate DCI allocated in subsequent symbols.

[0150] Furthermore, in the case where multiple UEs are determined to share DMRS, such as Figure 16B As shown, at aggregation level 2, even if two CCEs are allocated in different PRBs, terminal 200 can use the DMRS in the first PRB where each CCE is allocated for channel estimation. This approach prevents precoding changes for each CCE, but reduces the amount of DMRS resources by the amount of DMRS allocated in subsequent PRBs. Furthermore, when DMRSs are spatially or code-multiplexed, a portion of the DMRS multiplexed in the first symbol can be used for preceding symbols and another portion for succeeding symbols.

[0151] The above describes the operation examples 1-1 to 1-3.

[0152] As described above, in this embodiment, for mapping of CCEs and REGs arranged in a CORESET, the number of REGs per CCE is set to a power of 2, and the size of the REG bundle is set to a power of 2.

[0153] That is, the multiple REGs that make up a CCE are divided into powers of 2, using the REG bundle size as a unit. This simplifies REG mapping design. For example, by also setting the number of symbols in a CORESET to a power of 2, REGs are evenly allocated within each symbol within each CCE, using the REG bundle as a unit. This makes the number of REGs uniform across symbols in one or more CCEs used for DCI transmission, preventing variations in the received SINR per symbol and simplifying power adjustment between CCEs.

[0154] Furthermore, in this embodiment, the REG mapping configuration for a case where the number of symbols is a power of 2 is used as a reference. Based on this REG mapping configuration, through symbol puncturing, repetition, or rate matching, it is possible to implement REG mapping for a CORESET with a symbol number other than a power of 2. Consequently, even when the number of symbols in a CORESET is not a power of 2, the number of REGs can be made uniform between symbols, preventing variations in the received SINR per symbol and simplifying power adjustment between CCEs.

[0155] As described above, according to this embodiment, the CCEs constituting the CORESET can be appropriately arranged.

[0156] Furthermore, in the above description, the number of REGs per CCE is 4 (=2 2 ), REG bundle size is 2 (=2 1 ) is an example of REG mapping in the case of , but the REG bundle size can also be set to 4 (=2 2 In this case, the REGs constituting the CCE are arranged in the same symbol. In addition, the number of REGs constituting the CCE (the number of REGs per CCE) is 8 (=2 3 ), the REG bundle size can be set to 2 (=2 1 )、4(=2 2 ) or 8(=2 3 ).

[0157] Furthermore, in the above description, the case where base station 100 notifies terminal 200 of the CORESET configuration information configured via upper layer signaling is described. However, the CORESET configuration information may be defined between base station 100 and terminal 200. In this case, notification of the CORESET configuration via upper layer signaling is not required.

[0158] (Implementation Method 2)

[0159] The base station and terminal of this embodiment have the same basic structure as the base station 100 and terminal 200 of embodiment 1, so the same Figure 7 and Figure 8 To explain.

[0160] In this embodiment, regarding the mapping of CCEs and REGs in a core set, the number of REGs per CCE is set to 6, and the size of the REG bundle is changed according to the number of symbols in the core set.

[0161] In this way, even when the number of REGs per CCE is 6, the number of REGs arranged in each symbol can be made uniform when the number of symbols in the CORESET is 2, 3, or 4.

[0162] Hereinafter, an example of operation of this embodiment will be described in detail.

[0163] In the following, it is assumed that the number of REGs per CCE is 6, the REG bundling size is 3 when the number of symbols in a core set is a power of 2 (1, 2, 4, 8, ...), and the REG bundling size is 2 when the number of symbols in a core set is 3 or 6. Furthermore, an aggregation level of 2 is assumed.

[0164] Figures 17A to 17D An example of REG mapping according to this embodiment is shown.

[0165] <When the number of CORESET symbols is a power of 2>

[0166] Figure 17A and Figure 17B This shows an example of REG mapping when the number of symbols in CORESET is a power of 2. Specifically, Figure 17A This shows an example of REG mapping when CORESET is 2 symbols. Figure 17B This shows an example of REG mapping when CORESET is 4 symbols.

[0167] like Figure 17A and Figure 17B As shown, when the number of code elements in CORESET is a power of 2, the REG bundling size is 3.

[0168] Here, if we assume a time-first mapping, then Figure 17A and Figure 17B As shown in , each CCE is configured in 2 symbols. Figure 17B As shown, when the CORESET is 4 symbols, three REGs constituting the two CCEs used for DCI transmission are arranged in each of the four symbols at aggregation level 2. Although not shown, when the number of symbols in the CORESET is another value that is a power of 2 (1 symbol or 8 symbols), the REG bundling size can also be set to 3.

[0169] <When the number of symbols in CORESET is 3 or 6>

[0170] Figure 17C This shows an example of REG mapping when CORESET is 3 symbols. Figure 17D This figure shows an example of REG mapping when CORESET is 6 symbols.

[0171] like Figure 17C and Figure 17D As shown, when the number of code elements in CORESET is 3 or 6, the REG bundling size is 2.

[0172] Here, if we assume a time-first mapping, then Figure 17C and Figure 17D As shown in , each CCE is configured in 3 codewords. Figure 17D As shown, when the CORESET is 6 symbols, at aggregation level 2, two REGs constituting two CCEs for DCI transmission are arranged in each of the 6 symbols.

[0173] Figure 18 、 Figure 19 、 Figure 20 、 Figure 21 These represent the case where the number of REGs per CCE is set to 6 and the number of symbols in CORESET is set to 2, 4, 3, and 6 (see Figures 17A to 17D ) is an example of mapping REGs for each aggregation level (AL1, AL2, AL4, AL8).

[0174] exist Figure 18 The number of symbols in the CORESET shown is 2, and Figure 20 The number of symbols of the CORESET shown is 3, and the number of REGs arranged in each symbol is equal in all aggregation levels.

[0175] In addition, Figure 19 The number of symbols in the CORESET shown is 4, and Figure 21 The number of symbols in the CORESET shown is 6. At aggregation levels 2 and above, the number of REGs arranged in each symbol is equal. Figure 19 When the number of symbols of the CORESET shown is 4, the REGs constituting the DCI are arranged in 2 symbols. Figure 21 When the number of symbols of the CORESET shown is 6, the REGs constituting the DCI are arranged in 3 symbols.

[0176] Thus, in this embodiment, the number of REGs per CCE is set to 6, and the REG bundle size is adjusted according to the number of symbols in the CORESET. Thus, within each CCE, REGs are evenly arranged within each symbol, using REG bundles as units. Consequently, the number of REGs becomes uniform across symbols within one or more CCEs used for DCI transmission, preventing variations in the received SINR per symbol and simplifying power adjustment between CCEs.

[0177] Furthermore, the CORESET codeword number 5, codeword number 7, etc. not shown in the above examples can be expanded to the actual CORESET codeword number by using truncation, rate matching or repetition, similar to action examples 1-3, with the mapping design of the codeword number close to the actual CORESET codeword number (for example, codeword number 2, 3, 4, 6) as the benchmark.

[0178] Furthermore, the number of symbols in CORESET may be limited to 1, 2, 3, 4, 6, or 8, which are easy to allocate to the 6 REGs per CCE.

[0179] The embodiments of the present invention have been described above.

[0180] Furthermore, in the above embodiment, physical mapping is used as an example for the frequency domain (PRB#), but logical mapping is also applicable. In the case of logical mapping, the logical mapping is changed to physical mapping, so even if the frequency domain is continuous in the logical mapping, it is configured in physically separated positions, thus achieving frequency diversity effect.

[0181] Furthermore, in order to obtain a frequency diversity effect, an example is shown in which the REGs constituting each CCE are arranged in PRBs that are bundled differently for each REG. However, the mapping of the REGs constituting each CCE is not limited to this.

[0182] In addition, the control resource set (CORESET) is sometimes also called a search space.

[0183] Furthermore, multiple CORESETs may be configured for the UE. For example, in the above embodiment, symbol #0 is shown as the first symbol in which the CORESET is configured, but other CORESETs may be configured from subsequent symbols.

[0184] Furthermore, the upper layer signaling may be replaced by MAC signaling. In the case of MAC signaling, the frequency of changes to the UE configuration can be increased compared to RRC signaling.

[0185] In addition, the DMRS may also be a reference signal with a different name.

[0186] Furthermore, the above-described Embodiment 1 and Embodiment 2 may be combined. That is, based on the case where the number of REGs per CCE is a power of 2 (Embodiment 1) and the case where the number of REGs per CCE is 6 (Embodiment 2), the base station 100 and the terminal 200 may determine the REG bundling size or the number of symbols in the CORESET and set the REG mapping.

[0187] The present invention can be implemented through software, hardware, or software in conjunction with hardware. Each functional block described in the above embodiments can be partially or entirely implemented as an integrated circuit, or LSI. Each process described in the above embodiments can also be partially or entirely controlled by a single LSI or a combination of LSIs. An LSI can be composed of individual chips or a single chip, encompassing some or all of the functions. An LSI can also include data input and output. Depending on the degree of integration, an LSI is sometimes referred to as an IC, system LSI, super LSI, or ultra LSI. Integrated circuit methods are not limited to LSIs; they can also be implemented using dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, can also be used. The present invention can also be implemented as digital processing or analog processing. Furthermore, with advances in semiconductor technology or other technologies derived therefrom, if integrated circuit technology that can replace LSIs emerges, such technology can naturally be used to integrate functional blocks. There is also the possibility of applying biotechnology, etc.

[0188] The base station of the present invention includes: a circuit that allocates a downlink control signal to a control channel area composed of multiple control channel elements (CCE); and a transmitter that sends the downlink control signal, where the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0189] In the base station of the present invention, the number of symbols in which the control channel region is allocated is a power of 2.

[0190] In the base station of the present invention, the REGs constituting one CCE are arranged in the time direction with priority given to the frequency direction using the bundling size as a unit.

[0191] In the base station of the present invention, the circuit arranges the downlink control signal in the time direction with priority over the frequency direction in units of the CCE.

[0192] In the base station of the present invention, the REGs constituting one CCE are arranged in a plurality of symbols of the same frequency in units of the bundling size.

[0193] In the base station of the present invention, a reference signal is allocated to the first symbol among the plurality of symbols, and no reference signal is allocated to the remaining symbols.

[0194] The base station of the present invention includes: a circuit that allocates a downlink control signal to a control channel area composed of multiple control channel elements (CCE); and a transmitter that sends the downlink control signal, the number of resource element groups (REGs) constituting the CCE is 6, and when the number of code elements configured in the control channel area is a power of 2, the bundling size representing the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is 3, and when the number of code elements configured in the control channel area is 3 or 6, the bundling size is 2.

[0195] The terminal of the present invention includes: a receiver that receives a downlink control signal in a control channel area composed of multiple control channel elements (CCE); and a circuit that decodes the downlink control signal, wherein the number of resource element groups (REGs) constituting the CCE is a power of 2, indicating that the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0196] The communication method of the present invention includes the following steps: allocating a downlink control signal to a control channel area composed of multiple control channel elements (CCE), sending the downlink control signal, the number of resource element groups (REGs) constituting the CCE is a power of 2, and the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE is a power of 2.

[0197] The communication method of the present invention includes the following steps: receiving a downlink control signal in a control channel area composed of multiple control channel elements (CCE), decoding the downlink control signal, the number of resource element groups (REGs) constituting the CCE being a power of 2, and the bundling size of the number of REGs configured in adjacent resource blocks among the REGs constituting the CCE being a power of 2.

[0198] One embodiment of the present invention is useful for a mobile communication system.

[0199] Description of labels

[0200] 100 base stations

[0201] 101CORESET setting unit

[0202] 102DCI generation unit

[0203] 103, 207 error correction coding units

[0204] 104, 208 modulation units

[0205] 105, 209 signal distribution unit

[0206] 106, 210 sending unit

[0207] 107, 201 receiving units

[0208] 108, 202 signal separation unit

[0209] 109, 204 demodulation units

[0210] 110, 205 error correction decoding unit

[0211] 200 Terminal

[0212] 203DCI receiving unit

[0213] 206 Setting information receiving unit

Claims

1. A base station, comprising: a circuit for setting a control resource set CORESET in a physical downlink control channel PDCCH comprising a control channel element CCE; as well as a transmitter for transmitting a downlink control signal in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and The REG bundling size of the REG bundling varies according to the number of symbols of the CORESET.

2. The base station according to claim 1, wherein The number of symbols of the CORESET is indicated by higher layer signaling.

3. The base station according to claim 1, wherein The number of symbols of the CORESET is the duration of the CORESET. 4 . The base station according to claim 1 , wherein when the number of symbols of the core set is 2 or 3, the CCEs are arranged on a plurality of symbols of the core set. The base station according to claim 1 , wherein: A common demodulation reference signal DMRS is used for each REG bundle in the REG bundle. The base station according to claim 1 , wherein: REGs included in each of the REG bundles are adjacent to each other.

7. A communication method, comprising: A control resource set CORESET is set in a physical downlink control channel PDCCH including a control channel element CCE; as well as sending downlink control signals in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and The REG bundling size of the REG bundling varies according to the number of symbols of the CORESET.

8. The communication method according to claim 7, wherein: The number of symbols of the CORESET is indicated by higher layer signaling.

9. The communication method according to claim 7, wherein: The number of symbols of the CORESET is the duration of the CORESET.

10. The communication method according to claim 7, wherein when the number of symbols of the CORESET is 2 or 3, the CCE is arranged over a plurality of symbols of the CORESET.

11. The communication method according to claim 7, wherein: A common demodulation reference signal DMRS is used for each REG bundle in the REG bundle.

12. The communication method according to claim 7, wherein: REGs included in each of the REG bundles are adjacent to each other.

13. An integrated circuit for a base station, comprising: A controller circuit that controls: A control resource set CORESET is set in a physical downlink control channel PDCCH including a control channel element CCE; as well as sending downlink control signals in the CORESET, wherein the CCE is formed by six resource element groups REG in the CORESET, the six REGs are bundled into a REG bundle, and The REG bundling size of the REG bundling varies according to the number of symbols of the CORESET.

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