Communication device and communication method

Abstract

To provide a communication device capable of properly setting the radio waveform.SOLUTION: The communication device includes: a control circuit that sets a radio waveform of a signal depending on the radio frequency band used to transmit or receive signals; and a communication circuit that transmits or receives signals based on the setting of the radio waveform.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a communication device and a communication method. [Background technology]

[0002] In cellular wireless communications, including 5G NR (New Radio access technology), communications are carried out using baseband radio waveforms. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TS 38.300, V15.3.0 “NR; NR and NG-RAN Overall Description; Stage 2 (Release 16)”, 2021-06 [Non-patent document 2] Kosuke Yamazaki, Takeo Ozeki, Yoshiaki Amano, Takahide Murakami, Hiroyuki Shinbo, and Yoji Kishi, "PROPOSAL FOR A USER-CENTRIC RAN ARCHITECTURE TOWARDS BEYOND 5G," IEICE Technical Report, vol. 121, no. 189, SAT2021-43, pp. 4-10, October 2021. Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is room for discussion on how to appropriately configure the radio waveform.

[0005] Non-limiting embodiments of the present disclosure contribute to providing a communication device and a communication method that can appropriately set a radio waveform. [Means for solving the problem]

[0006] A communication device according to one embodiment of the present disclosure includes a control circuit that sets a radio waveform of a signal in accordance with a radio frequency band used to transmit or receive the signal, and a communication circuit that transmits or receives the signal based on the setting of the radio waveform.

[0007] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0008] According to an embodiment of the present disclosure, the radio waveform can be appropriately set.

[0009] Further advantages and benefits of certain aspects of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0010] [Figure 1] A block diagram showing an example of the configuration of a part of a communication device. [Figure 2] A block diagram showing an example of the configuration of a communication device [Figure 3] A diagram showing an example of radio waveform generation operation DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0012] In cellular wireless communications including 5G NR, for example, communications are carried out using baseband radio waveforms (also called signal waveforms) defined by the system, regardless of radio frequency bands (also called carrier frequencies or frequency bands).

[0013] For example, in Long Term Evolution (LTE), OFDM with a cyclic prefix (CP) added (hereinafter referred to as "CP-OFDM") is used for the downlink radio waveform, and DFT-S-OFDM with a CP added (hereinafter referred to as "CP-DFT-S-OFDM") is used for the uplink radio waveform. Also, for example, in 5G NR, CP-OFDM is used for the downlink radio waveform, and CP-OFDM or CP-DFT-S-OFDM is used for the uplink radio waveform (see, for example, Non-Patent Document 1).

[0014] OFDM stands for Orthogonal Frequency Division Multiplexing, and DFT-S-OFDM stands for Discrete Fourier Transform-spread-OFDM, which is also sometimes called Single Carrier-Frequency Division Multiple Access (SC-FDMA).

[0015] In the 6G system (sixth generation mobile communication system), the use of radio waves in the terahertz band (or sub-terahertz band) of 100 GHz or higher is being considered. For example, Non-Patent Document 2 proposes a system that uses terahertz waves for communication near terminals.

[0016] In the 6G system, for example, in addition to the terahertz band, existing frequency bands will also be used, so radio waves in a variety of radio frequency bands, from frequency bands below 1 GHz (sub-gigahertz band) to the terahertz band (e.g., 300 GHz band), can be used. If communications are performed using the same radio waveform for these various radio frequency bands, various restrictions may arise.

[0017] For example, multicarrier transmission such as OFDM has good error rate characteristics in frequency-selective fading environments, and is expected to realize high-speed transmission through Multiple-Input Multiple Output (MIMO) transmission. On the other hand, OFDM has a high signal peak-to-average power ratio (PAPR) and requires a large backoff for the power amplifier input, which requires transmission at a power level sufficiently low compared to the maximum output of the power amplifier. For example, the higher the radio frequency band, the greater the propagation attenuation, and it is difficult to achieve high output with a low-cost power amplifier. Therefore, when OFDM is used as a radio waveform, the transmittable power is limited, which can easily lead to a reduction in the coverage area.

[0018] In addition, single-carrier transmission such as DFT-S-OFDM has a low PAPR, does not require a large backoff for the power amplifier input, and can transmit at high power according to the maximum output of the power amplifier, thereby enabling a wide coverage area.However, single-carrier transmission is prone to degradation in error rate performance in frequency-selective fading environments, and throughput is likely to be limited.

[0019] In one non-limiting embodiment of the present disclosure, for example, a method for appropriately setting (or generating) a signal of a radio waveform to be used in each of various radio frequency bands will be described. For example, a communication device (e.g., at least one of a base station and a terminal) may set a radio waveform according to the radio frequency band used for communication and generate a baseband signal of the set radio waveform.

[0020] [Communication System Overview] A communication system according to an embodiment of the present disclosure includes at least one communication device 100. The communication device 100 may be, for example, a base station (also referred to as a gNB) or a terminal (for example, user equipment (UE)).

[0021] The communication device 100 may, for example, perform at least one of transmission and reception of signals in a plurality of radio frequency bands.

[0022] Fig. 1 is a block diagram showing an example of the configuration of a portion of a communication device 100. In the communication device 100 shown in Fig. 1, a control unit (e.g., corresponding to a control circuit) sets a radio waveform of a signal according to a radio frequency band used for transmitting or receiving the signal. A communication unit (e.g., a communication circuit) transmits or receives the signal based on the setting of the radio waveform.

[0023] [Example of communication device configuration] FIG. 2 is a block diagram showing an example of the configuration of communication device 100 according to this embodiment.

[0024] At least one of the encoding unit 101 to the windowing processing unit 108 and the CP removal unit 120 to the decoding unit 127 shown in Fig. 2 may be included in, for example, the control unit shown in Fig. 1. Furthermore, at least one of the DA conversion unit 109 to the AD conversion unit 119 shown in Fig. 2 may be included in, for example, the communication unit shown in Fig. 1.

[0025] <Send process> 2, the processing performed by coding section 101, modulation section 102, precoding section 103, DFT section 104, resource mapping section 105, inverse fast fourier transform (IFFT) section 106, CP adding section 107, and windowing processing section 108 may be referred to as "baseband signal processing." Also, in FIG. 2, the processing performed by DA conversion section 109, low pass filter (LPF) 110, up-converter (UPC) 111, band pass filter (BPF) 112, power amplifier (PA) 113, and duplexer 114 may be referred to as "analog / radio frequency (RF) processing."

[0026] 2, the DFT unit 104, resource mapping unit 105, IFFT unit 106, CP adding unit 107, and windowing processing unit 108 may be included in a "radio waveform generating unit 150" that generates a radio waveform. The processing of each component included in the radio waveform generating unit 150 may be omitted, for example, in accordance with an instruction from a control unit (not shown). For example, the communication device 100 (for example, a control unit) may determine whether or not to perform processing of each component included in the radio waveform generating unit 150 depending on the radio frequency band (for example, the terahertz band or the millimeter wave band) used for signal transmission (an example will be described later).

[0027] 2, the UPC 111, the BPF 112, the PA 113, and the duplexer 114 may be provided separately for each radio frequency band used for transmission. In the example shown in FIG. 2, the UPC 111-1, the BPF 112-1, the PA 113-1, and the duplexer 114-1 may be provided for a low frequency band (e.g., the millimeter wave band), and the UPC 111-2, the BPF 112-2, the PA 113-2, and the duplexer 114-2 may be provided for a high frequency band (e.g., the terahertz band).

[0028] Furthermore, when MIMO transmission is performed using a plurality of antennas in each radio frequency band, the processing after Precoding section 103 shown in FIG. 2 may be performed for each antenna system.

[0029] In FIG. 2, an encoding unit 101 performs error correction encoding on a signal using an encoding method such as turbo encoding, low density parity check (LDPC) encoding, or polar encoding.

[0030] The modulation unit 102 maps the coded bit string to an IQ constellation such as Quadrature Phase Shift Keying (QPSK) and 16-Quadrature Amplitude Modulation (16QAM), for example, and generates modulation symbols.

[0031] Precoding section 103 performs, for example, precoding processing for MIMO transmission (for example, weighting processing on modulation symbols) on modulation symbols input from modulation section 102. Note that if communication device 100 does not perform MIMO transmission, precoding section 103 does not need to perform processing.

[0032] DFT section 104 performs DFT processing (also called DFT spreading or DFT precoding) on ​​the signal input from precoding section 103, for example.

[0033] The resource mapping unit 105 maps the signal after the DFT processing to frequency resources (for example, subcarriers or resource blocks (RBs)) used for transmission.

[0034] The IFFT unit 106 performs, for example, IFFT processing on the signal mapped to the frequency resource.

[0035] CP adding section 107 adds a CP by, for example, copying a sample of a part of the signal after IFFT (for example, the rear part of the OFDM symbol) to the beginning.

[0036] The windowing processing unit 108 performs windowing processing on the signal (for example, OFDM symbols) after adding a CP. The windowing processing is processing for reducing out-of-band radiation power due to discontinuity between OFDM symbols, for example. For the windowing processing, for example, a window function of a root raised cosine waveform may be used. Furthermore, the windowing processing unit 108 may perform weighted overlap and add (WOLA) processing, for example, to overlap adjacent OFDM symbols.

[0037] The DA conversion unit 109 performs digital-to-analog conversion on the signal (radio waveform) input from the radio waveform generation unit 150 (for example, the windowing processing unit 108).

[0038] The LPF 110 performs LPF processing to pass desired low-frequency components of the signal input from the DA conversion unit 109, for example.

[0039] The UPC 111, for example, up-converts the frequency of the signal input from the LPF 110 to a transmission frequency. Note that the UPC 111 may be, for example, a multi-stage up-converter.

[0040] The BPF 112 performs filtering on the signal input from the UPC 111, for example, to pass desired band components.

[0041] The PA 113 amplifies, for example, the signal input from the BPF 112 to a desired transmission power.

[0042] The duplexer 114 switches between transmission and reception, which may be switched at the timing of switching between uplink and downlink in a Time Division Duplex (TDD) frame, for example.

[0043] <Reception process> 2, the processing of the duplexer 114, low noise amplifier (LNA) 115, BPF 116, down-converter (DNC) 117, LPF 118, and AD conversion unit 119 may be referred to as "analog / RF processing." Also, in FIG. 2, the processing of the CP removal unit 120, fast Fourier transform (FFT) unit 121, resource demapping unit 122, inverse discrete fourier transform (IDFT) unit 123, channel estimation unit 124, MIMO reception processing unit 125, demodulation unit 126, and decoding unit 127 may be referred to as "baseband signal processing."

[0044] 2, the CP removal unit 120, FFT unit 121, resource demapping unit 122, IDFT unit 123, channel estimation unit 124, and MIMO reception processing unit 125 may be included in a "radio waveform processing unit 160" that performs processing related to radio waveforms. The processing of each component included in the radio waveform processing unit 160 may be omitted, for example, in accordance with an instruction from a control unit (not shown). For example, the communication device 100 (for example, a control unit) may determine whether or not to perform processing of each component included in the radio waveform processing unit 160 depending on the radio frequency band (for example, the terahertz band or the millimeter wave band) used to receive signals (an example will be described later).

[0045] 2, the duplexer 114, the LNA 115, the BPF 116, and the DNC 117 may be provided separately for each radio frequency band used for reception. In the example shown in FIG. 2, the duplexer 114-1, the LNA 115-1, the BPF 116-1, and the DNC 117-1 may be provided for a low frequency band (e.g., the millimeter wave band), and the duplexer 114-2, the LNA 115-2, the BPF 116-2, and the DNC 117-2 may be provided for a high frequency band (e.g., the terahertz band).

[0046] In FIG. 2, the received signal output from the duplexer 114 is input to the LNA 115 .

[0047] The LNA 115 amplifies the received signal input from the duplexer 114 .

[0048] The BPF 116 performs filtering on the signal input from the LNA 115 to pass desired band components.

[0049] The DNC 117 down-converts the frequency of the signal input from the BPF 116 .

[0050] The LPF 118 performs LPF processing to pass desired low-frequency components of the signal input from the DNC 117 .

[0051] The AD conversion unit 119 performs analog-to-digital conversion on the signal input from the LPF 118 .

[0052] The CP removal unit 120 removes the CP added to the signal input from the AD conversion unit 119 .

[0053] The FFT unit 121 performs FFT processing (for example, conversion from time components to frequency components) on the signal input from the CP removal unit 120.

[0054] The resource demapping unit 122 uses the signal input from the FFT unit 121 to extract a signal of a frequency resource (for example, a subcarrier or a resource block) to which data is allocated.

[0055] The IDFT unit 123 performs IDFT processing on the signal input from the resource demapping unit 122 .

[0056] The channel estimation unit 124 estimates channel (propagation path) fluctuations using, for example, a reference signal (for example, a reference signal (RS)) included in the signal after FFT.

[0057] The MIMO reception processing unit 125 performs MIMO reception processing including channel equalization on the signal input from the IDFT unit 123, and detects each multiplexed stream signal, based on, for example, the channel estimation result input from the channel estimation unit 124. Note that when MIMO transmission is not performed, the MIMO reception processing unit performs channel equalization but does not need to detect stream signals.

[0058] The demodulation unit 126 converts modulation symbols modulated by a modulation method such as QPSK and 16QAM into a bit string.

[0059] The decoding unit 127 performs a decoding process on a bit string that has been coded using a coding method such as an LDPC code.

[0060] [Example of communication device operation] Next, an example of the operation of the communication device 100 will be described.

[0061] As an example, an operation example of the radio waveform generating unit 150 of the communication device 100 will be described.

[0062] Whether or not each processing unit of the radio waveform generation unit 150 (for example, the DFT unit 104, the IFFT unit 106, the CP adding unit 107, and the windowing processing unit 108) operates may be set according to the radio frequency band used for transmission. For example, the operation of each processing unit of the radio waveform generation unit 150 may differ depending on the radio frequency band used for transmission. Therefore, for example, the radio waveform generated in the radio waveform generation unit 150 may differ depending on the radio frequency band used for transmission.

[0063] In the following, as an example, a case will be described in which terahertz waves (for example, an example of a high frequency band) and millimeter waves (for example, an example of a low frequency band) are used as radio frequency bands used by communication device 100 for transmission.

[0064] For example, when using terahertz waves, the radio waveform generation unit 150 may set the radio waveform so that IFFT processing is not performed on the transmission signal, and when using millimeter waves, the radio waveform generation unit 150 may set the radio waveform so that IFFT processing is performed on the transmission signal. As a result, when using terahertz waves, transmission does not use subcarriers, and when using millimeter waves, transmission uses subcarriers. Therefore, when using terahertz waves, it is possible to reduce the PAPR compared to when using millimeter waves.

[0065] Furthermore, for example, when terahertz waves are used, the radio waveform generation unit 150 performs DFT processing on the transmission signal as a radio waveform setting, whereas when millimeter waves are used, the radio waveform setting does not require DFT processing on the transmission signal. As a result, when terahertz waves are used, multi-carrier transmission is performed, and when millimeter waves are used, single-carrier transmission is performed. Therefore, when millimeter waves are used, it is possible to reduce the PAPR compared to when terahertz waves are used.

[0066] Furthermore, for example, when terahertz waves are used, the radio waveform generating section 150 may not add a CP to the transmission signal as part of the radio waveform settings, but when millimeter waves are used, the radio waveform generating section 150 may add a CP to the transmission signal as part of the radio waveform settings. As a result, when millimeter waves are used, the addition of a CP improves resistance to delayed waves (multipath) compared to when terahertz waves are used.

[0067] Furthermore, for example, when terahertz waves are used, the radio waveform generating section 150 may not perform windowing processing on the transmission signal as a radio waveform setting, but may perform windowing processing as a radio waveform setting when millimeter waves are used. As a result, when millimeter waves are used, out-of-band radiation power is reduced (or radiation is in a narrower band) compared to when terahertz waves are used.

[0068] FIG. 3 shows examples (operation examples 1 to 4) of whether or not each processing unit of the radio waveform generating unit 150 (for example, the DFT unit 104, the IFFT unit 106, the CP adding unit 107, and the windowing processing unit 108) operates.

[0069] In FIG. 3, "◯" indicates that the corresponding processing unit performs an operation, and "×" indicates that the corresponding processing unit does not perform an operation.

[0070] <Example 1> In the first operational example, for example, the DFT process is not performed, but the IFFT process, the CP addition, and the windowing process are performed.

[0071] In Operation Example 1, DFT processing is not performed, and IFFT processing is performed, thereby converting data signals mapped to frequency domain resources (e.g., subcarriers) into time domain signals and transmitting the signals. Therefore, in Operation Example 1, the communication device 100 transmits the transmission signals as OFDM signals (e.g., multicarrier signals).

[0072] Furthermore, in the first operational example, the addition of a CP improves resistance to delayed waves (multipath), and the windowing process reduces out-of-band radiation power.

[0073] In addition, since Operation Example 1 is multi-carrier transmission, the PAPR is higher and the transmission output is more likely to be limited compared to single-carrier transmission. Therefore, Operation Example 1 is preferably applied to cases where, for example, propagation attenuation is smaller, delay dispersion is larger, or the usable frequency band may be more limited. Therefore, Operation Example 1 may be applied, for example, when the radio frequency is low.

[0074] <Example 2> In the second operational example, all of the DFT processing, IFFT processing, CP addition, and windowing processing are performed.

[0075] In the second operation example, the DFT process is performed before the IFFT process, thereby converting the frequency components of the data signal mapped to each subcarrier back into a time domain signal. Therefore, in the second operation example, the communication device 1 transmits the transmission signal as a single-carrier signal.

[0076] Furthermore, in the second operational example, the addition of a CP improves resistance to delayed waves (multipath), and the windowing process reduces out-of-band radiation power (or radiates radiation to a narrower band).

[0077] Operation Example 2 is preferably applied to cases where, for example, delay dispersion is large or the available frequency band may be more limited. Furthermore, since Operation Example 2 is single-carrier transmission, it can suppress PAPR compared to multi-carrier transmission, and therefore may be applied to cases where the radio frequency is higher than Operation Example 1.

[0078] <Example 3> In the third operational example, the DFT process and the IFFT process are performed, but the CP addition and the windowing process are not performed.

[0079] Operation example 3 is single-carrier transmission, similar to operation example 2. Furthermore, in operation example 3, CP addition and windowing processing are not performed, so there is low resistance to delayed waves (multipath), and out-of-band radiation power is likely to increase (or radiation to a wider band is likely). For this reason, operation example 3 is preferably applied to cases where delay dispersion is smaller or where the available frequency band is wider.

[0080] Therefore, compared with Operation Example 1 and Operation Example 2, Operation Example 3 may be applied when the radio frequency is higher.

[0081] <Example 4> In the fourth operational example, none of the DFT processing, IFFT processing, CP addition, and windowing processing is performed.

[0082] Therefore, in operation example 4, the communication device 100 transmits the data signal as is as a time domain signal sequence. Therefore, in operation example 4, the transmission signal is a single-carrier signal to which neither CP addition nor windowing processing is performed.

[0083] Furthermore, in Operation Example 4, similar to Operation Example 3, the resistance to delayed waves (multipath) is low and out-of-band radiation power is likely to increase (or radiation to a wider band is likely to occur). For this reason, Operation Example 4 is preferably applied to cases where delay dispersion is smaller or where the usable frequency band is wider. Therefore, Operation Example 4 may be applied to cases where the radio frequency is higher compared to Operation Examples 1 and 2.

[0084] Furthermore, Operation Example 4 does not perform DFT processing and IFFT processing, for example, does not use subcarriers for transmission, and therefore can reduce the PAPR compared to Operation Example 3. Therefore, Operation Example 4 may be applied when the radio frequency is higher than Operation Example 3, for example.

[0085] Furthermore, since Operation Example 4 does not perform DFT processing and IFFT processing, it is possible to reduce power consumption. For example, the wider the signal bandwidth, the higher the power consumption of DFT processing and IFFT processing tends to be. Therefore, compared with Operation Examples 1 to 3, Operation Example 4 may be applied when the radio frequency at which a wider bandwidth can be used is high.

[0086] Operation examples 1 to 4 have been described above.

[0087] As an example, the radio waveform generating unit 150 may generate a radio waveform by the processing of Operation Example 1 when using a radio frequency band of millimeter waves (e.g., 24 GHz to 72 GHz), and may generate a radio waveform by the processing of any of Operation Examples 2 to 4 when using a radio frequency band of terahertz waves (e.g., 100 GHz or higher).

[0088] Alternatively, the radio waveform generating unit 150 may generate a radio waveform by processing in operation example 1 or operation example 2 when using a millimeter wave radio frequency band, and may generate a radio waveform by processing in operation example 3 or operation example 4 when using a terahertz wave radio frequency band.

[0089] Alternatively, the radio waveform generating unit 150 may generate a radio waveform by the processing of Operation Example 1 when using a radio frequency in the sub-6 GHz band (e.g., 100 MHz to 6 GHz), generate a radio waveform by the processing of Operation Example 2 when using a millimeter wave radio frequency band, and generate a radio waveform by the processing of Operation Example 3 or Operation Example 4 when using a terahertz wave radio frequency band.

[0090] The association between the radio frequency band used for transmission and the radio waveform used in that radio frequency band (for example, the radio waveform generated by any of operation examples 1 to 4 shown in Figure 3) is not limited to the example described above, and other associations may also be used.

[0091] For example, the higher the radio frequency used for transmission, the more the radio waveform generating section 150 may generate a radio waveform according to the operation example with the higher number among operation examples 1 to 4 shown in FIG.

[0092] As described above, in this embodiment, the communication device 100 sets the radio waveform of the transmission signal according to the frequency band (for example, carrier frequency) used for transmission. This enables the communication device 100 to transmit the data signal using a radio waveform suitable for the radio frequency band used for transmission, thereby enabling improvement in throughput and coverage performance.

[0093] Furthermore, as shown in FIG. 3, the communication device 100 switches whether or not each processing unit in the radio waveform generation unit 150 is performing a process (On or Off) depending on the radio frequency band used for transmission (or the radio waveform to be generated). For this reason, in the communication device 100, a processing unit (for example, the radio waveform generation unit 150) for generating a radio waveform is shared among a plurality of different radio frequency bands. Therefore, according to this embodiment, the communication device 100 does not need to have an individual processing unit for each radio frequency band, for example, and the configuration can be simplified. Furthermore, by switching whether or not a process is performed depending on the radio frequency band, the communication device 100 can generate a radio waveform suitable for the radio frequency band to be used through simple processing.

[0094] The embodiments of the present disclosure have been described above.

[0095] (Variation 1) In the first modification, the radio waveform (for example, the operation of the radio waveform generating section 150) may be set based on the propagation environment of the communication in the communication device 100 (communication in the radio frequency band used).

[0096] For example, in a line-of-sight (LOS) environment, which is a propagation environment assumed in a communication system, propagation attenuation tends to be small, and the amount of delay of delayed waves (multipath) tends to be small and the number of delayed waves tends to be small.

[0097] On the other hand, in a non-line-of-sight (NLOS) environment, which is a propagation environment assumed in a communication system, communication is performed using diffracted or reflected waves, so propagation attenuation is large and the delay amount of delayed waves tends to be large and numerous.

[0098] Therefore, for example, the communication device 100 may generate a radio waveform according to operation example 1, which is multi-carrier (OFDM) transmission, in a line-of-sight environment, and may generate a radio waveform according to any of operation examples 2 to 4, which are single-carrier transmission, in a non-line-of-sight environment.

[0099] Alternatively, the communication device 100 may apply, for example, the above-mentioned operational example when the radio frequency is high (e.g., the operational example with the higher number in Figure 3) in a line-of-sight environment, and may apply the above-mentioned operational example when the radio frequency is low (e.g., the operational example with the lower number in Figure 3) in a non-line-of-sight environment.

[0100] In other words, communication device 100 may perform the same operation as when using terahertz waves as described above in a line-of-sight environment, and may perform the same operation as when using millimeter waves as described above in a non-line-of-sight environment.

[0101] <Variation 2> In the second modification, the operation of the radio waveform (for example, the radio waveform generating unit 150) may be set based on the antenna directivity used in the radio frequency band used by the communication device 100.

[0102] For example, the stronger the antenna directivity (for example, the thinner the generated beam), the greater the transmission power (power radiated from the antenna) that the communication device 100 can transmit with. Also, for example, the stronger the antenna directivity, the smaller the amount of delay of the delayed waves and the fewer the number of delayed waves tend to be.

[0103] Therefore, for example, when the antenna directivity is strong (or when a strong directional antenna is used), the communication device 100 may generate a radio waveform using operation example 1, which is multi-carrier (OFDM) transmission, and when the antenna directivity is weak (or when a weak directional antenna is used), the communication device 100 may generate a radio waveform using one of operation examples 2 to 4, which are single-carrier transmission.

[0104] Alternatively, for example, when the antenna directivity is strong, the communication device 100 may apply the above-mentioned operational example for a high radio frequency (for example, the operational example with a higher number in Figure 3), and when the antenna directivity is weak, the communication device 100 may apply the above-mentioned operational example for a low radio frequency (for example, the operational example with a lower number in Figure 3).

[0105] In other words, when the antenna directivity is strong, the communication device 100 may perform the same operation as when using terahertz waves as described above, and when the antenna directivity is weak, the communication device 100 may perform the same operation as when using millimeter waves as described above.

[0106] The antenna directivity may be expressed as antenna gain. For example, the communication device 100 may determine that the antenna directivity is strong when the antenna gain is equal to or greater than a threshold, and may determine that the antenna directivity is weak when the antenna gain is less than the threshold. For example, the communication device 100 may set an operation for generating a radio waveform according to the antenna gain.

[0107] <Variation 3> In the third modification, the radio waveform (for example, the operation of the radio waveform generating unit 150) may be set based on the subcarrier spacing (SCS) used in the radio frequency band used by the communication device 100.

[0108] For example, the narrower the subcarrier spacing, the longer the OFDM symbol length and the more likely it is that a long CP can be used, whereas the wider the subcarrier spacing, the shorter the OFDM symbol length and the more likely it is that it is difficult to use a long CP.

[0109] Therefore, for example, when the subcarrier spacing is narrow (e.g., when the subcarrier spacing is less than a threshold), the communication device 100 may generate a radio waveform according to operation example 1 or operation example 2, in which a CP is added, and when the subcarrier spacing is wide (e.g., when the subcarrier spacing is equal to or greater than a threshold), the communication device 100 may generate a radio waveform according to operation example 3 or operation example 4, in which a CP is not added.

[0110] For example, when the subcarrier spacing is wide, the communication device 100 may perform the same operation as when using terahertz waves as described above, and when the subcarrier spacing is narrow, the communication device 100 may perform the same operation as when using millimeter waves as described above.

[0111] Alternatively, for example, when the subcarrier spacing is wide, the communication device 100 may generate a radio waveform by an operation that does not add a CP (for example, a process in which DFT processing and CP addition are not performed, and IFFT processing and windowing processing are performed) as a variation of operation example 1.

[0112] <Variation 4> In the fourth modification, the radio waveform (for example, the operation of the radio waveform generating section 150) may be set based on the CP length used in the radio frequency band used by the communication device 100.

[0113] For example, a longer CP length is more likely to be used in a propagation environment with a larger delay amount of delayed waves (multipath), and a shorter CP length is more likely to be used in a propagation environment with a smaller delay amount.

[0114] Therefore, for example, for the same reason as in variant example 1, when the CP length is long (for example, when the CP length is equal to or greater than a threshold), the communication device 100 may generate a radio waveform using operation example 1, which is multi-carrier (OFDM) transmission, and when the CP length is short (for example, when the CP length is less than a threshold), the communication device 100 may generate a radio waveform using one of operation examples 2 to 4, which are single-carrier transmission.

[0115] For example, when the CP length is short, the communication device 100 may perform the same operation as when using terahertz waves as described above, and when the CP length is long, the communication device 100 may perform the same operation as when using millimeter waves as described above.

[0116] Modifications 1 to 4 have been described above.

[0117] It is also possible to combine at least two of the above-described embodiment and modifications 1 to 4. For example, the radio waveform applied in each frequency band may be set (or switched or changed) according to predetermined conditions such as the propagation environment or settings of the communication device 100 (for example, antenna gain, subcarrier spacing, or CP length).

[0118] For example, the radio waveform may be determined depending on the combination of the radio frequency band to be used, as described in the first embodiment, and the propagation environment, as described in the first modification. For example, the communication device 100 may generate different radio waveforms for line-of-sight and non-line-of-sight environments when using millimeter waves, and line-of-sight and non-line-of-sight environments when using terahertz waves.

[0119] 3, Operation Example 1 may be called "OFDM (or CP OFDM)," Operation Examples 2 and 3 may be called "DFT-S-OFDM" or "SC-FDMA," and Operation Example 4 may be called "Single Carrier (SC)." Operation Example 2 may be called "CP DFT-S-OFDM" or "CP SC-FDMA," and Operation Example 3 may be called "CP-less DFT-S-OFDM" or "CP-less SC-FDMA."

[0120] The millimeter wave band may also be read as the frequency of "Frequency range 2 (FR2)", and the sub-6 GHz band may also be read as the frequency of "Frequency range 1 (FR1)".

[0121] The radio frequency is also sometimes called the carrier frequency.

[0122] Furthermore, the number of frequency bands used by the communication device 100 is not limited to two or three, and may be four or more frequency bands. For example, the radio waveform generation unit 150 may set the radio waveforms to be generated in each of the four or more frequency bands individually for each frequency band. The frequency bands may be, for example, Operating bands (such as n1 and n2) described in 3GPP TS38.104 V17.4.0.

[0123] Furthermore, in the above embodiment, the operation on the transmitting side of the communication device 100 has been described. However, the communication device 100 may also perform radio waveform processing on the receiving side (for example, the radio waveform processing unit 160) depending on the radio frequency band used for reception. For example, the communication device 100 may determine (or assume) the radio waveform to be applied to a signal depending on the radio frequency band used for the signal to be received. For example, in the case of Operation Example 1 shown in FIG. 3, the radio waveform processing unit 160 may perform CP removal and FFT processing, but not IDFT processing. For example, in the case of Operation Example 2 shown in FIG. 3, the radio waveform processing unit 160 may perform CP removal, FFT processing, and IDFT processing. For example, in the case of Operation Example 3 shown in FIG. 3, the radio waveform processing unit 160 may perform FFT processing and IDFT processing without performing CP removal. For example, in the case of Operation Example 4 shown in FIG. 3, the radio waveform processing unit 160 may not perform CP removal, FFT processing, or IDFT processing.

[0124] Furthermore, in the communication device 100, the frequency bands used for transmission and reception, or the number of frequency bands, may differ.

[0125] Furthermore, the operation example shown in Fig. 3 is just an example, and the operation of the radio waveform generation unit 150 is not limited to the operation shown in Fig. 3. For example, the radio waveform generation unit 150 may perform IFFT processing and CP addition without performing DFT processing and windowing processing. Alternatively, for example, the radio waveform generation unit 150 may perform IFFT processing without performing DFT processing, CP addition, and windowing processing.

[0126] Moreover, instead of windowing processing, filtering processing may be performed, or other waveform shaping processing for limiting the frequency band may be used.

[0127] Furthermore, in the above embodiment, terahertz waves and millimeter waves have been described as examples of radio frequency bands, but this is not limited to these, and the frequency bands used for transmission or reception in communication device 100 may be other frequency bands or combinations of other frequency bands.

[0128] 2 (e.g., encoding section 101, modulation section 102, precoding section 103, DFT section 104, resource mapping section 105, IFFT section 106, CP adding section 107 and windowing section 108, CP removing section 120, FFT section 121, resource demapping section 122, IDFT section 123, channel estimating section 124, MIMO receiving processing section 125, demodulation section 126 and decoding section 127) is an example, and is not limited to this. For example, some of the configuration for performing baseband processing shown in FIG. 2 may not be provided, and other components may be included.

[0129] Furthermore, in communication device 100, the setting of the radio waveform to be used in each frequency band (or whether or not it is set) may be explicitly or implicitly notified (or set) to communication device 100 by another device, may be set in advance in communication device 100, or may be specified in advance in a standard.

[0130] The base station may be referred to as a gNodeB or a gNB, and the terminal may be referred to as a UE.

[0131] Furthermore, the notation "··· part" in the above-described embodiments may be replaced with other notations such as "··· circuitry," "··· device," "··· unit," or "··· module."

[0132] The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may be called an IC, system LSI, super LSI, or ultra LSI.

[0133] The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0134] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

[0135] The present disclosure may be implemented in any type of apparatus, device, or system (collectively referred to as a communications apparatus) that has a communications function. The communications apparatus may include a wireless transceiver and processing / control circuitry. The wireless transceiver may include a receiver and a transmitter, or both functions. The wireless transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0136] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (such as appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0137] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0138] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0139] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0140] A communication device according to one embodiment of the present disclosure includes a control circuit that sets a radio waveform of a signal in accordance with a radio frequency band used to transmit or receive the signal, and a communication circuit that transmits or receives the signal based on the setting of the radio waveform.

[0141] In one embodiment of the present disclosure, when a first radio frequency band is used, the control circuit performs Discrete Fourier Transform (DFT) processing on the signal as the radio waveform setting, and when a second radio frequency band lower than the first radio frequency band is used, the control circuit does not perform the DFT processing on the signal as the radio waveform setting.

[0142] In one embodiment of the present disclosure, when a first radio frequency band is used, the control circuit does not add a cyclic prefix (CP) to the signal as a setting of the radio waveform, and when a second radio frequency band lower than the first radio frequency band is used, the control circuit adds the CP to the signal as a setting of the radio waveform.

[0143] In one embodiment of the present disclosure, when a first radio frequency band is used, the control circuit does not perform windowing processing on the signal as a setting of the radio waveform, and when a second radio frequency band lower than the first radio frequency band is used, the control circuit performs the windowing processing as a setting of the radio waveform.

[0144] In one embodiment of the present disclosure, when a first radio frequency band is used, the control circuit does not perform Inverse Fast Fourier Transform (IFFT) processing on the signal as the radio waveform setting, and when a second radio frequency band lower than the first radio frequency band is used, the control circuit performs the IFFT processing on the signal as the radio waveform setting.

[0145] In one embodiment of the present disclosure, the control circuit sets a radio waveform of the signal based on a propagation environment of communication in the radio frequency band.

[0146] In one embodiment of the present disclosure, the control circuit sets the radio waveform of the signal based on the directivity of an antenna used in the radio frequency band.

[0147] In one embodiment of the present disclosure, the control circuit sets the radio waveform of the signal based on the subcarrier spacing used in the radio frequency band.

[0148] In one embodiment of the present disclosure, the control circuit sets the radio waveform of the signal based on a cyclic prefix (CP) length used in the radio frequency band.

[0149] In a communication method according to one embodiment of the present disclosure, a communication device sets a radio waveform of a signal according to a radio frequency band used for transmitting or receiving the signal, and transmits or receives the signal based on the setting of the radio waveform. [Industrial Applicability]

[0150] One aspect of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0151] 100 Communication equipment 101 Encoding section 102 Modulation section 103 Precoding section 104 DFT section 105 Resource Mapping Unit 106 IFFT section 107 CP addition part 108 Windowing processing section 109 DA conversion section 110,118 LPF 111 UPC 112,116 BPF 113 PA 114 Duplexer 115 LNA 117 DNC 119 AD conversion section 120 CP removal section 121 FFT section 122 Resource Demapping Unit 123 IDFT Department 124 Channel Estimation Unit 125 MIMO receiving processing unit 126 Demodulation section 127 Decoding Unit

Claims

1. A control circuit that sets a radio waveform of a signal according to a radio frequency band used for transmitting or receiving the signal; a communication circuit that transmits or receives the signal based on the setting of the radio waveform; Equipped with the control circuit does not add a cyclic prefix (CP) to the signal as a setting of the radio waveform when using a first radio frequency band, and adds the CP to the signal as a setting of the radio waveform when using a second radio frequency band lower than the first radio frequency band. Communication equipment.

2. A control circuit that sets a radio waveform of a signal according to a radio frequency band used for transmitting or receiving the signal; a communication circuit that transmits or receives the signal based on the setting of the radio waveform; Equipped with the control circuit does not perform windowing processing on the signal as a setting of the radio waveform when a first radio frequency band is used, and performs the windowing processing as a setting of the radio waveform when a second radio frequency band lower than the first radio frequency band is used. Communication equipment.

3. A control circuit that sets a radio waveform of a signal according to a radio frequency band used for transmitting or receiving the signal; a communication circuit that transmits or receives the signal based on the setting of the radio waveform; Equipped with the control circuit does not perform Inverse Fast Fourier Transform (IFFT) processing on the signal as the setting of the radio waveform when a first radio frequency band is used, and performs the IFFT processing on the signal as the setting of the radio waveform when a second radio frequency band lower than the first radio frequency band is used; Communication equipment.

4. A control circuit that sets a radio waveform of a signal based on a communication propagation environment in a radio frequency band used for transmitting or receiving the signal; a communication circuit that transmits or receives the signal based on the setting of the radio waveform; A communication device comprising:

5. A control circuit that sets a radio waveform of a signal based on an antenna directivity used in a radio frequency band used for transmitting or receiving the signal; a communication circuit that transmits or receives the signal based on the setting of the radio waveform; A communication device comprising:

6. the control circuit sets a radio waveform of the signal based on a subcarrier spacing used in the radio frequency band.

6. A communication device according to claim 1.

7. the control circuit sets a radio waveform of the signal based on a cyclic prefix (CP) length used in the radio frequency band.

6. A communication device according to claim 1.

8. The communication device setting a radio waveform of the signal according to a radio frequency band used for transmitting or receiving the signal; transmitting or receiving the signal based on the setting of the radio waveform; When a first radio frequency band is used, a cyclic prefix (CP) is not added to the signal as a setting of the radio waveform, and when a second radio frequency band lower than the first radio frequency band is used, the CP is added to the signal as a setting of the radio waveform. Communication method.

9. A communication device comprising: setting a radio waveform of the signal according to a radio frequency band used for transmitting or receiving the signal; transmitting or receiving the signal based on the setting of the radio waveform; When a first radio frequency band is used, windowing processing is not performed on the signal as a setting of the radio waveform, and when a second radio frequency band lower than the first radio frequency band is used, the windowing processing is performed as a setting of the radio waveform. Communication method.

10. A communication device comprising: setting a radio waveform of the signal according to a radio frequency band used for transmitting or receiving the signal; transmitting or receiving the signal based on the setting of the radio waveform; When a first radio frequency band is used, the radio waveform setting is such that an Inverse Fast Fourier Transform (IFFT) process is not performed on the signal, and when a second radio frequency band lower than the first radio frequency band is used, the radio waveform setting is such that the IFFT process is performed on the signal. Communication method.

11. A communication device comprising: setting a radio waveform of the signal based on a communication propagation environment in a radio frequency band used for transmitting or receiving the signal; transmitting or receiving the signal based on the setting of the radio waveform; Communication method.

12. A communication device comprising: setting a radio waveform of the signal based on an antenna directivity used in a radio frequency band used for transmitting or receiving the signal; transmitting or receiving the signal based on the setting of the radio waveform; Communication method.

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