WO2018179433A1 - Wireless device, wireless system, and processing method - Google Patents

Abstract

A first wireless device (110) comprises a transmission unit (111) and a control unit (112). The transmission unit (111) is capable of sending data signals to a second wireless device (120). A control unit (112) causes the transmission unit (111) to: transmit data signals at a first frequency and a second frequency that have a first interval therebetween, during a first hour; and transmit data signals at a third frequency and a fourth frequency having a second interval therebetween that differs from the first interval, during a second hour differing from the first hour.

Description

Wireless device, wireless system, and processing method

The present invention relates to a wireless device, a wireless system, and a processing method.

3GPP (3rd Generation Partnership Project), which has developed specifications for a mobile communication system called the so-called LTE (Long Term Evolution) system, has begun basic study work for formulating specifications for so-called fifth generation mobile communication systems.

Regarding the fifth generation mobile communication system, ITU-R presents eMBB, mMTC, and URLLC as main services (for example, see Non-Patent Document 1 below). ITU-R is an abbreviation for International Telecommunication Union Radiocommunications Sector (International Telecommunication Union Radiocommunication Division). eMBB is an abbreviation for enhanced Mobile Broad Band. mMTC is an abbreviation for massive machine type communications. URLLC is an abbreviation for Ultra-Reliable and Low Latency Communications.

3GPP has determined the wireless requirements of the next generation system based on the recommendation of ITU-R and has started the basic study of the system (for example, see Non-Patent Document 2 below). As techniques for improving the reliability of wireless transmission, techniques relating to frequency diversity for transmitting the same data at different frequencies, time diversity for transmitting the same data at different times, and the like are known.

However, with the above-described conventional technology, there is a case where the transmission delay cannot be reduced while suppressing the deterioration of the reception characteristics. For example, when time diversity is used, if the time interval for transmitting the same data is lengthened, the transmission delay increases. Also, if the time interval for transmitting the same data is shortened, the time diversity effect is reduced and the reception characteristics are degraded.

In one aspect, an object of the present invention is to provide a wireless device, a wireless system, and a processing method that can reduce transmission delay while suppressing deterioration in reception characteristics.

In order to solve the above-described problem and achieve the object, in one embodiment, a wireless device capable of transmitting a data signal to another wireless device has a first frequency having a first interval with each other at a first time, and Transmitting the data signal at each of the second frequencies, and transmitting the data signal at each of a third frequency and a fourth frequency having a second interval different from the first interval at a second time different from the first time. A transmitting wireless device, a wireless system and a processing method are proposed.

In another embodiment, a wireless device capable of receiving a data signal from another wireless device is transmitted at each of a first frequency and a second frequency having a first interval in a first time. Radio that receives the data signal and receives the data signal transmitted at each of a third frequency and a fourth frequency having a second interval different from the first interval at a second time different from the first time. An apparatus, a wireless system and a processing method are proposed.

In one aspect, the present invention has an effect that transmission delay can be reduced while suppressing deterioration of reception characteristics.

FIG. 1 is a diagram illustrating an example of a wireless system according to the first embodiment. FIG. 2 is a diagram illustrating an example of a low-delay transmission system to which the wireless system according to the embodiment is applied. FIG. 3 is a diagram of an example of the transmitter according to the first embodiment. FIG. 4 is a diagram of an example of the receiver according to the first embodiment. FIG. 5 is a diagram illustrating an example of a hardware configuration of the transmitter according to the embodiment. FIG. 6 is a diagram illustrating an example of a hardware configuration of the receiver according to the embodiment. FIG. 7 is a diagram of an example of diversity transmission (Nmax = 2) by the transmitter according to the first embodiment. FIG. 8 is a sequence diagram illustrating an example of processing by the low-delay transmission system according to the first embodiment. FIG. 9 is a flowchart of an example of processing performed by the transmitter according to the first embodiment. FIG. 10 is a flowchart of an example of processing performed by the receiver according to the first embodiment. FIG. 11 is a diagram (part 1) illustrating an example of determination of F and ΔF by the receiver according to the first embodiment. FIG. 12 is a diagram (part 2) illustrating an example of determination of F and ΔF by the receiver according to the first embodiment. FIG. 13 is a diagram illustrating an example of diversity transmission (Nmax = 3) by the transmitter according to the first embodiment. FIG. 14 is a sequence diagram illustrating an example of processing by the low-delay transmission system according to the second embodiment. FIG. 15 is a flowchart of an example of processing performed by the transmitter according to the second embodiment. FIG. 16 is a flowchart of an example of processing performed by the receiver according to the second embodiment.

Hereinafter, embodiments of a wireless device, a wireless system, and a processing method according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
(Radio system according to the first embodiment)
FIG. 1 is a diagram illustrating an example of a wireless system according to the first embodiment. As illustrated in FIG. 1, the wireless system 100 according to the embodiment includes a first wireless device 110 and a second wireless device 120. In the example illustrated in FIG. 1, a case where a data signal is wirelessly transmitted from the first wireless device 110 to the second wireless device 120 will be described.

The first wireless device 110 includes a transmission unit 111 and a control unit 112. The transmission unit 111 can transmit a data signal to the second radio apparatus 120 under the control of the control unit 112. The control unit 112 controls the transmission unit 111 to transmit the same data signal at each of the first frequency and the second frequency in the first time. The first time is, for example, a time resource assigned to transmission of a data signal from the first radio apparatus 110 to the second radio apparatus 120. The first frequency and the second frequency are each frequency having a first interval. The first interval is a frequency interval greater than zero.

In addition, the control unit 112 controls the transmission unit 111 to transmit the same data signal as the data signal transmitted in the first time at each of the third frequency and the fourth frequency in the second time. . The third frequency and the fourth frequency are frequencies having a second interval. The second interval is a frequency interval greater than 0 and different from the first interval. The second time is a time resource different from the first time. For example, the second time is a time resource after the first time or a time resource before the first time.

The second radio apparatus 120 includes a receiving unit 121 and a control unit 122. The receiving unit 121 can receive a data signal from the first radio apparatus 110 under the control of the control unit 122. The control unit 122 performs control to cause the reception unit 121 to receive the data signal transmitted by each of the first frequency and the second frequency in the first time.

Further, the control unit 122 performs control to cause the reception unit 121 to receive data signals transmitted by the third frequency and the fourth frequency, respectively, in the second time described above. However, the control unit 122 may not cause the reception unit 121 to receive the data signal at the second time when the reception unit 121 can decode the data signal received at the first time. In this case, when the receiving unit 121 cannot decode the data signal received at the first time, the control unit 122 performs control to cause the receiving unit 121 to receive the data signal at the second time.

Thus, according to the wireless system 100, in the first time, the same data signal can be transmitted by each of the first frequency and the second frequency having the first interval. Further, in the second time different from the first time, the same data signal can be transmitted by each of the third frequency and the fourth frequency having a second interval different from the first interval. Thereby, the receiving characteristic in the 2nd radio | wireless apparatus 120 can be improved according to each effect of a frequency diversity, a time diversity, and a frequency space | interval diversity. The reception characteristic is, for example, an error rate such as BLER (Block Error Rate).

Also, for example, even if the interval between the first time and the second time is reduced in order to reduce the transmission delay, the decrease in the effect of time diversity can be compensated by frequency interval diversity. Thereby, it is possible to reduce transmission delay while suppressing deterioration of reception characteristics. For this reason, for example, a highly reliable and low-delay radio system can be realized.

In addition, the control unit 112 of the first radio apparatus 110 provides, for example, information that can specify each of the above-described frequencies (first frequency, second frequency, third frequency, and fourth frequency) to the transmission unit 111. Control may be performed to transmit to the two wireless devices 120. Thereby, for example, even in the configuration in which the first radio apparatus 110 determines each frequency described above, the second radio apparatus 120 can receive the data signal from the first radio apparatus 110 with diversity.

The first frequency and the third frequency described above can be set to the same reference frequency, for example. The reference frequency is, for example, a frequency assigned for data signal transmission from the first radio apparatus 110 to the second radio apparatus 120. In this case, the information that can identify each frequency described above includes, for example, information indicating the first frequency, information indicating the first interval (for example, F described later), and the second interval (for example, F1 described later). It can be realized by the information indicating.

In this case, the second radio apparatus 120 can specify the first frequency and the third frequency based on the information indicating the first frequency. Further, the second radio apparatus 120 can specify the second frequency based on the information indicating the first frequency and the information indicating the first interval. Further, the second radio apparatus 120 can identify the fourth frequency based on information indicating the first frequency and information indicating the second interval.

Alternatively, instead of the information indicating the second interval described above, information indicating a difference between the first interval and the second interval (for example, ΔF described later) may be used. In this case, the second radio apparatus 120 includes information indicating the first interval, information indicating the difference between the first interval and the second interval, information specifying the second interval and indicating the first frequency, The fourth frequency can be specified based on the specified second interval.

As described above, the first radio apparatus 110 transmits information indicating a part of the above-described frequencies and information indicating a difference between the part of the frequencies and the other frequencies. The amount of signaling from the first wireless device 110 to the second wireless device 120 can be reduced. However, the information that can specify each frequency described above is not limited thereto, and may be information that directly indicates each frequency, for example.

Further, the information that can identify each frequency described above may be individually transmitted by the first wireless device 110 to the second wireless device 120, or each wireless device that performs wireless communication with the first wireless device 110. 1st radio | wireless apparatus 110 may alert | report.

For example, the control unit 112 of the first radio apparatus 110 may control the transmission unit 111 to transmit the information that can specify the first time and the second time to the second radio apparatus 120. Good. Thereby, for example, even in the configuration in which the first radio apparatus 110 determines the first time and the second time described above, the second radio apparatus 120 can receive the data signal from the first radio apparatus 110 with diversity.

(Low-delay transmission system to which the wireless system according to the embodiment is applied)
FIG. 2 is a diagram illustrating an example of a low-delay transmission system to which the wireless system according to the embodiment is applied. The low delay transmission system 200 shown in FIG. 2 includes a transmitter 210 and a receiver 220. The first radio apparatus 110 shown in FIG. 1 can be realized by the transmitter 210, for example. The second radio apparatus 120 shown in FIG. 1 can be realized by the receiver 220, for example.

In the example shown in FIG. 2, a case where the transmitter 210 wirelessly transmits a data signal to the receiver 220 will be described. For wireless transmission of this data signal, the IP layer or Layer 1/2 is used. IP is an abbreviation for Internet Protocol. The transmitter 210 is a base station such as eNB (evolved Node B). Receiver 220 is a terminal such as a UE (User Equipment: user terminal). However, the transmitter 210 may be a terminal such as a UE. The receiver 220 may be a base station such as an eNB.

Further, the low-delay transmission system 200 shown in FIG. 2 can be applied to automatic driving control of a car, remote control of a robot in a factory, a dangerous place, or the like. Wireless communication for these controls requires high reliability and low delay characteristics. For example, in the next generation mobile communication system specified by 3GPP, services such as the above-described URLLC are newly introduced.

For example, in data transmission related to human life such as automatic driving of automobiles, both low delay and ultra-high reliability are required. In 3GPP, for Layer 1/2 of data in such a wireless section, the transmission delay time is within 1 [ms] and the data transmission success rate is defined as 10 to the fifth power.

In the transmission of data signals from the transmitter 210 to the receiver 220, for example, HARQ is used as a time diversity transmission method. HARQ is an abbreviation for Hybrid Automatic Repeat reQuest (hybrid automatic repeat request). In this case, the HARQ may be, for example, a HARQ of a chase combination that combines power on the receiving side. However, the time diversity transmission used for transmission of the data signal from the transmitter 210 to the receiver 220 is not limited to HARQ, and can be various time diversity transmissions.

(Transmitter according to the first embodiment)
FIG. 3 is a diagram of an example of the transmitter according to the first embodiment. As illustrated in FIG. 3, the transmitter 210 includes, for example, an antenna 301, an RF receiving unit 302, and a reception control signal processing unit 303. Further, the transmitter 210 includes, for example, a transmission control unit 304, a data signal generation unit 305, a pilot signal generation unit 306, a control signal generation unit 307, multiplexing units 308a to 308c, an RF transmission unit 309, an antenna, and the like. 310 and a retransmission control unit 311. RF is an abbreviation for Radio Frequency.

The antenna 301 receives a signal wirelessly transmitted from another wireless device such as the receiver 220, and outputs the received signal to the RF receiving unit 302. The RF receiver 302 performs an RF reception process on the signal output from the antenna 301. The RF reception processing by the RF receiver 302 includes, for example, amplification, frequency conversion from the RF band to the baseband, conversion from an analog signal to a digital signal, and the like. The RF reception unit 302 outputs the signal subjected to the RF reception process to the reception control signal processing unit 303.

The reception control signal processing unit 303 demodulates the control signal included in the signal output from the RF reception unit 302 and decodes the demodulated control signal. Reception control signal processing section 303 then outputs the control signal obtained by decoding to transmission control section 304. The control signal output from the reception control signal processing unit 303 to the transmission control unit 304 includes a response signal (ACK or NACK) from the receiver 220 to the data signal transmitted from the transmitter 210 to the receiver 220.

The control signal output from the reception control signal processing unit 303 to the transmission control unit 304 includes, for example, wireless section characteristic information indicating an evaluation value of wireless section characteristics (wireless quality) between the transmitter 210 and the receiver 220. Is included. As an example of the wireless section characteristic information, a CQI value indicating the wireless section characteristic with an index value can be used. CQI is an abbreviation for Channel Quality Indicator.

Further, the control signal output from the reception control signal processing unit 303 to the transmission control unit 304 includes information indicating F and ΔF determined by the receiver 220, for example. F and ΔF will be described later.

The transmission control unit 304 controls data signal generation by the data signal generation unit 305, control signal generation by the control signal generation unit 307, and retransmission control by the retransmission control unit 311. For example, the transmission control unit 304 selects the MCS value of the data signal to be transmitted to the receiver 220 based on the radio section characteristic information output from the reception control signal processing unit 303. Then, the transmission control unit 304 controls the data signal generation unit 305 to apply the modulation scheme and the coding scheme indicated by the selected MCS value to the data signal. MCS is an abbreviation for Modulation and Coding Scheme.

Also, the transmission control unit 304 controls the frequency of each identical data signal generated by the data signal generation unit 305 based on the information indicating F and ΔF output from the reception control signal processing unit 303. Also, the transmission control unit 304 controls the control signal generation unit 307 to transmit a control signal including the selected MCS value. If the response signal from the receiver 220 output from the reception control signal processing unit 303 is NACK, the transmission control unit 304 controls the retransmission control unit 311 to retransmit the corresponding data signal.

A data signal to be transmitted from the transmitter 210 to the receiver 220 is input to the data signal generation unit 305 and the retransmission control unit 311. The data signal generation unit 305 generates first to fourth data signals in accordance with control from the transmission control unit 304. The first to fourth data signals are data signals indicating the same data. The first and second data signals are each data signal transmitted by the same time resource and transmitted by each frequency resource whose frequency interval is F. The third and fourth data signals are data signals transmitted by the same time resource after the first and second data signals and transmitted by each frequency resource whose frequency interval is F1. The first to fourth data signals will be described later (see, for example, FIG. 7).

Further, when the retransmission data is output from the retransmission control unit 311, the data signal generation unit 305 performs the first to second operations based on the retransmission data output from the retransmission control unit 311 according to the control from the transmission control unit 304. 4 data signals are generated. Then, the data signal generation unit 305 outputs the generated first and second data signals to the multiplexing unit 308a. In addition, the data signal generation unit 305 outputs the generated third and fourth data signals to the multiplexing unit 308b.

Pilot signal generation section 306 generates pilot signals having different frequencies, and outputs the generated pilot signals to multiplexing sections 308a and 308b, respectively.

The control signal generation unit 307 generates first to fourth control signals corresponding to the first to fourth data signals, respectively, according to the control from the transmission control unit 304. Then, the control signal generation unit 307 outputs the generated first and second control signals to the multiplexing unit 308a. In addition, the control signal generation unit 307 outputs the generated third and fourth control signals to the multiplexing unit 308b.

The multiplexing unit 308 a includes the first and second data signals output from the data signal generation unit 305, the data signal output from the pilot signal generation unit 306, and the third and third data signals output from the control signal generation unit 307. 4 control signals are frequency multiplexed (or frequency time multiplexed). Then, the multiplexing unit 308a outputs the frequency multiplexed (or frequency time multiplexed) signal to the multiplexing unit 308c.

The multiplexing unit 308b includes the third and fourth data signals output from the data signal generation unit 305, the data signal output from the pilot signal generation unit 306, and the third and third data signals output from the control signal generation unit 307. 4 control signals are frequency multiplexed (or frequency time multiplexed). Then, the multiplexing unit 308b outputs the frequency multiplexed (or frequency time multiplexed) signal to the multiplexing unit 308c.

The multiplexing unit 308c frequency multiplexes the signals output from the multiplexing units 308a and 308b, and outputs the frequency-multiplexed signal to the RF transmission unit 309.

The RF transmission unit 309 performs RF transmission processing of the signal output from the multiplexing unit 308c. The RF transmission processing by the RF transmission unit 309 includes, for example, conversion from a digital signal to an analog signal, frequency conversion from a baseband to an RF band, amplification, and the like. The RF transmission unit 309 outputs the signal subjected to the RF transmission process to the antenna 310. The antenna 310 wirelessly transmits the signal output from the RF transmission unit 309 to another communication device (for example, the receiver 220).

The retransmission control unit 311 has a retransmission data buffer for storing the input data signal. Then, according to control from transmission control section 304, retransmission control section 311 outputs the data signal stored in the retransmission data buffer to data signal generation section 305 as retransmission data.

1 can be realized by, for example, the data signal generation unit 305, the multiplexing units 308a to 308c, the RF transmission unit 309, the antenna 310, and the retransmission control unit 311. The control unit 112 of the first radio apparatus 110 illustrated in FIG. 1 can be realized by the transmission control unit 304, for example.

In the example illustrated in FIG. 3, the configuration including two multiplexing units (multiplexing units 308a and 308b) has been described as the configuration when the number of continuous automatic transmissions (Nmax) by the transmitter 210 is two. It is not restricted to such a configuration. For example, when the number of continuous automatic transmissions (Nmax) by the transmitter 210 is three times or more, a configuration including three or more multiplexing units may be employed.

(Receiver according to the first embodiment)
FIG. 4 is a diagram of an example of the receiver according to the first embodiment. As illustrated in FIG. 4, the receiver 220 includes, for example, an antenna 401, an RF reception unit 402, a reception data signal processing unit 403, a reception data signal buffer 404, and an ACK / NACK signal generation unit 405. . The receiver 220 includes a reception pilot signal processing unit 406, a radio section characteristic evaluation unit 407, a control signal generation unit 408, a reception control signal processing unit 409, an RF transmission unit 410, and an antenna 411. .

The antenna 401 receives a signal wirelessly transmitted from another communication device (for example, the transmitter 210) and outputs the signal to the RF receiving unit 402. The RF reception unit 402 performs an RF reception process on the signal output from the antenna 401. The RF reception processing by the RF reception unit 402 includes, for example, amplification, frequency conversion from the RF band to the baseband, conversion from an analog signal to a digital signal, and the like. The RF reception unit 402 outputs the signal subjected to the RF reception processing to the reception data signal processing unit 403, the reception pilot signal processing unit 406, and the reception control signal processing unit 409.

The reception data signal processing unit 403 performs reception processing of a data signal included in the signal output from the RF reception unit 402. For example, the reception data signal processing unit 403 performs reception processing by a decoding method based on the MCS value output from the reception control signal processing unit 409. Reception data signal processing section 403 outputs the data signal obtained by the reception processing to reception data signal buffer 404. Reception data signal processing section 403 outputs the data signal error detection result in the reception processing to ACK / NACK signal generation section 405.

The reception data signal buffer 404 stores the data signal output from the reception data signal processing unit 403. The data signal stored by the reception data signal buffer 404 is used for combining with the retransmitted data signal, for example, when the HARQ method is used as the retransmission method.

The ACK / NACK signal generation unit 405 generates a response signal based on the error detection result output from the reception data signal processing unit 403. For example, the ACK / NACK signal generation unit 405 generates an ACK when the reception data signal processing unit 403 obtains a normal data signal, and the reception data signal processing unit 403 does not obtain a normal data signal. Generates a NACK. Then, the ACK / NACK signal generation unit 405 outputs the generated response signal (ACK or NACK) to the RF transmission unit 410 as a control signal.

The reception pilot signal processing unit 406 performs reception processing of a pilot signal included in the signal output from the RF reception unit 402, and outputs the pilot signal obtained by the reception processing to the radio section characteristic evaluation unit 407. Radio section characteristic evaluation section 407 calculates radio section characteristic information between transmitter 210 and receiver 220 based on the pilot signal output from reception pilot signal processing section 406.

For example, the radio section characteristic evaluation unit 407 calculates the radio section characteristic information using a measurement result such as RSSI or RSRP based on the reception result output from the reception pilot signal processing unit 406. RSSI is an abbreviation for Received Signal Strength Indicator (received signal strength). RSRP is an abbreviation for Reference Signal Received Power (reference signal received power). For the wireless section characteristic information, for example, a CQI value indicating the wireless section characteristic (quality) as an index value can be used.

Moreover, the radio section characteristic evaluation unit 407 may determine the above-described F and ΔF based on the reception result output from the reception pilot signal processing unit 406. The wireless section characteristic evaluation unit 407 outputs the calculated wireless section characteristic information, F and ΔF, to the control signal generation unit 408.

The control signal generation unit 408 generates a control signal including the wireless section characteristic information, F and ΔF output from the wireless section characteristic evaluation unit 407, and outputs the generated control signal to the RF transmission unit 410. The reception control signal processing unit 409 performs reception processing of a control signal included in the signal output from the RF reception unit 402. The reception control signal processing unit 409 outputs the MCS value included in the control signal obtained by the reception processing to the reception data signal processing unit 403.

The RF transmitter 410 receives the response signal (ACK or NACK) output from the ACK / NACK signal generator 405 and the control signal output from the control signal generator 408. The RF transmission unit 410 performs an RF transmission process on the input signal. The RF transmission processing by the RF transmission unit 410 includes, for example, conversion from a digital signal to an analog signal, frequency conversion from a baseband to an RF band, amplification, and the like. The RF transmission unit 410 outputs the signal subjected to the RF transmission process to the antenna 411. The antenna 411 wirelessly transmits the signal output from the RF transmission unit 410 to another communication device (for example, the transmitter 210).

1 can be realized by, for example, the antenna 401, the RF receiving unit 402, and the received data signal processing unit 403. The control unit 122 of the second radio apparatus 120 illustrated in FIG. 1 can be realized by the reception data signal processing unit 403 and the reception control signal processing unit 409, for example.

(Hardware configuration of transmitter according to embodiment)
FIG. 5 is a diagram illustrating an example of a hardware configuration of the transmitter according to the embodiment. The transmitter 210 illustrated in FIG. 3 can be realized by the communication apparatus 500 illustrated in FIG. 5, for example, when applied to a base station such as eNB. The communication device 500 includes a CPU 501, a memory 502, a wireless communication interface 503, and a wired communication interface 504. The CPU 501, the memory 502, the wireless communication interface 503, and the wired communication interface 504 are connected by a bus 509.

A CPU 501 (Central Processing Unit) controls the entire communication device 500. The memory 502 includes, for example, a main memory and an auxiliary memory. The main memory is, for example, a RAM (Random Access Memory). The main memory is used as a work area for the CPU 501. The auxiliary memory is, for example, a nonvolatile memory such as a magnetic disk, an optical disk, or a flash memory. Various programs for operating the communication device 500 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the CPU 501.

The wireless communication interface 503 is a communication interface that performs communication with the outside of the communication device 500 (for example, the receiver 220) wirelessly. The wireless communication interface 503 is controlled by the CPU 501. The wired communication interface 504 is a communication interface that performs communication with the outside of the communication device 500 (for example, a host device of the transmitter 210) by wire. The wired communication interface 504 is controlled by the CPU 501.

3 includes the antenna 301, the RF receiving unit 302, the RF transmitting unit 309, and the antenna 310, for example, included in the wireless communication interface 503. The reception control signal processing unit 303, the transmission control unit 304, the data signal generation unit 305, and the pilot signal generation unit 306 illustrated in FIG. 3 can be realized by at least one of the CPU 501 and the wireless communication interface 503, for example. The control signal generation unit 307, the multiplexing units 308a to 308c, and the retransmission control unit 311 illustrated in FIG. 3 can be realized by at least one of the CPU 501 and the wireless communication interface 503, for example.

(Hardware configuration of receiver according to embodiment)
FIG. 6 is a diagram illustrating an example of a hardware configuration of the receiver according to the embodiment. When applied to a terminal such as a UE, for example, the receiver 220 illustrated in FIG. 4 can be realized by the communication apparatus 600 illustrated in FIG. 6, for example. The communication device 600 includes a CPU 601, a memory 602, a user interface 603, and a wireless communication interface 604. The CPU 601, the memory 602, the user interface 603, and the wireless communication interface 604 are connected by a bus 609.

The CPU 601 governs overall control of the communication device 600. The memory 602 includes, for example, a main memory and an auxiliary memory. The main memory is, for example, a RAM. The main memory is used as a work area for the CPU 601. The auxiliary memory is a non-volatile memory such as a magnetic disk or a flash memory. Various programs for operating the communication device 600 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the CPU 601.

The user interface 603 includes, for example, an input device that receives an operation input from the user, an output device that outputs information to the user, and the like. The input device can be realized by a key (for example, a keyboard) or a remote controller, for example. The output device can be realized by, for example, a display or a speaker. Further, an input device and an output device may be realized by a touch panel or the like. The user interface 603 is controlled by the CPU 601.

The wireless communication interface 604 is a communication interface that performs communication with the outside of the communication device 600 (for example, the transmitter 210) wirelessly. The wireless communication interface 604 is controlled by the CPU 601.

The antenna 401, the RF receiving unit 402, the RF transmitting unit 410, and the antenna 411 illustrated in FIG. 4 are included in the wireless communication interface 604, for example. The reception data signal processing unit 403, the reception data signal buffer 404, and the ACK / NACK signal generation unit 405 illustrated in FIG. 4 can be realized by at least one of the CPU 601 and the wireless communication interface 604, for example. Reception pilot signal processing section 406, wireless section characteristic evaluation section 407, control signal generation section 408, and reception control signal processing section 409 can be realized by at least one of CPU 601 and wireless communication interface 604, for example.

(Diversity transmission by the transmitter according to the first embodiment (Nmax = 2))
FIG. 7 is a diagram of an example of diversity transmission (Nmax = 2) by the transmitter according to the first embodiment. In FIG. 7, the horizontal axis indicates time, and the vertical axis indicates frequency. FIG. 7 illustrates a case where the number of times that the transmitter 210 continuously transmits the data signal to the receiver 220 (continuous automatic transmission number Nmax) is two.

Transmitter 210 wirelessly transmits data signals 711, 712, 721, 722 to receiver 220, for example. The data signals 711, 712, 721, 722 are data signals indicating the same data.

Data signals 711 and 712 are data signals transmitted at the same time t1. Data signals 721 and 722 are data signals transmitted at the same time t2. Data signals 711 and 721 are data signals transmitted at the reference frequency f_1. The reference frequency f_1 is a frequency used for transmitting a data signal from the transmitter 210 to the receiver 220, and is notified from the transmitter 210 to the receiver 220 by a radio control signal, for example. The data signal 712 is a data signal transmitted at a frequency f_2 whose frequency interval with the reference frequency f_1 is F. The data signal 722 is a data signal transmitted at a frequency f_3 having a frequency interval F1 from the reference frequency f_1.

That is, the frequency interval F is an interval between the reference frequency f_1 and the frequency f_2 (F = f_1−f_2). The frequency interval F1 is an interval between the reference frequency f_1 and the frequency f_3 (F = f_1−f_3). The difference between the frequency interval F and the frequency interval F1 is ΔF (F1 = F + ΔF). ΔF is a value smaller than 0 or larger than 0 (ΔF <0 or ΔF> 0).

Suppose that the time interval between the time t1 when the data signals 711 and 712 are transmitted and the time t2 when the data signals 721 and 722 are transmitted is T2. The time interval T2 is set to a sufficiently small value with respect to an allowable transmission delay amount (for example, 1 [ms]). Thus, in addition to the combination of time diversity and frequency diversity, the diversity effect can be further improved by using frequency interval diversity. For this reason, for example, the diversity effect which is reduced by reducing the time interval T2 in order to reduce the transmission delay can be compensated by the frequency interval diversity.

The receiver 220 performs diversity reception that decodes the original data based on at least one of the data signals 711, 712, 721, and 722. For example, the receiver 220 performs the decoding process in the order of the data signals 711, 712, 721, 722 until the data is successfully decoded. Alternatively, the data signals 711 and 712 may be combined to perform decoding processing, and if decoding fails, the data signals 721 and 722 may be combined to perform decoding processing. Alternatively, the receiver 220 may perform decoding processing by combining the data signals 711, 712, 721, 722. However, the diversity reception by the receiver 220 based on the data signals 711, 712, 721, 722 is not limited to these and can be various diversity receptions.

Further, for example, the transmitter 210 notifies the receiver 220 of the reference frequency f_1, and transmits control information such as F1, T2, Nmax, F, and ΔF using the reference frequency f_1. The receiver 220 receives the data signal 711 transmitted at the frequency f_1 based on the frequency f_1 notified from the transmitter 210, and controls F1, T2, Nmax, F, and ΔF transmitted at the frequency f_1. Information can be received.

Then, the receiver 220 receives the data signal 712 whose frequency is separated from the data signal 711 by F based on F included in the received control information. The receiver 220 receives a data signal 721 that is transmitted with a delay of T2 from the data signals 711 and 712, based on Nmax included in the received control information. Further, the receiver 220 receives a data signal 722 having a frequency separated from the data signal 721 by F1 based on F1 included in the received control information.

(Processing by the low-delay transmission system according to the first embodiment)
FIG. 8 is a sequence diagram illustrating an example of processing by the low-delay transmission system according to the first embodiment. In the transmitter 210 (for example, base station) and the receiver 220 (for example, terminal) of the low-delay transmission system 200 according to the first embodiment, for example, the steps shown in FIG. 8 are executed. Bidirectional communication between the transmitter 210 and the receiver 220 shown in FIG. 8 is performed by, for example, FDD or TDD. FDD is an abbreviation for Frequency Division Duplex. TDD is an abbreviation for Time Division Duplex.

First, the transmitter 210 wirelessly transmits a pilot signal to the receiver 220 (step S801). Further, transmitter 210 continues to transmit the pilot signal to receiver 220 wirelessly after step S801. Next, the receiver 220 determines CQI, F, and ΔF based on the measurement result of the pilot signal received in step S801 (step S802). A method for determining F and ΔF will be described later (see, for example, FIGS. 11 and 12).

Next, the receiver 220 transmits information indicating CQI, F, and ΔF determined in step S802 to the transmitter 210 (step S803). The transmission in step S803 can be executed using, for example, an RRC (Radio Resource Control) message from the receiver 220 to the transmitter 210 or a Layer-1 or Layer-2 control signal.

Next, the transmitter 210 determines F1, T2, and Nmax (the number of continuous automatic transmissions) (step S804). For example, the transmitter 210 calculates F1 by F1 = F + ΔF based on F and ΔF indicated by the information received in step S803. For example, transmitter 210 determines T2 and Nmax based on the CQI received in step S803 and the correspondence information in which the combination of T2 and Nmax is associated with each CQI. Alternatively, the transmitter 210 may determine T2 and Nmax based on the communication type of the receiver 220 and the like. In the example shown in FIG. 8, it is assumed that 2 is determined as Nmax.

Next, the transmitter 210 transmits information indicating F1, T2, and Nmax, F, and ΔF determined in step S804 to the receiver 220 (step S805). Note that the transmitter 210 may not transmit the information indicating F and ΔF in step S805. The transmission in step S805 can be executed using, for example, an RRC message from the transmitter 210 to the receiver 220 or a Layer-1 or Layer-2 control signal. Next, it is assumed that new data to be transmitted to the receiver 220 is generated in the transmitter 210 (step S806).

Next, the transmitter 210 wirelessly transmits the data signal generated by performing processing such as channel coding to the data generated in step S806 and the control signal to the receiver 220 (step S807). In step S807, the transmitter 210 transmits a data signal using the F indicated by the information received in step S803 at the reference frequency f_1 and the frequency f_2 whose frequency interval between the frequencies f_1 is F. (Frequency interval F). Further, the transmitter 210 transmits the control signal to the receiver 220 using the reference frequency f_1, for example.

Also, the control signal transmitted in step S807 includes information such as an MCS value for decoding the data signal transmitted in step S807, for example. On the other hand, the receiver 220 receives the data signal transmitted at the frequency interval F in step S807 using F determined in step S802 or F indicated by the information received in step S803. In addition, the receiver 220 decodes the received data signal based on the MCS value included in the received control signal.

Next, the transmitter 210 retransmits the data signal and the control signal wirelessly transmitted in step S807 to the receiver 220 at the timing when the continuous transmission interval T2 has elapsed from the wireless transmission in step S807 (step S808). In step S808, the transmitter 210 transmits a data signal at the reference frequency f_1 and frequency f_3 using F1 = F + ΔF based on F and ΔF indicated by the information received in step S803 (frequency interval F1). . The frequency f_3 is a frequency whose frequency interval with the frequency f_1 is F1. Further, the transmitter 210 transmits the control signal to the receiver 220 using the reference frequency f_1, for example. On the other hand, the receiver 220 is transmitted at the frequency interval F1 using F and ΔF determined in step S802 or F1 (= F + ΔF) calculated from F and ΔF indicated by the information received in step S803. Receive data signals. In addition, the receiver 220 decodes the received data signal based on the MCS value included in the received control signal.

Next, the receiver 220 wirelessly transmits a response signal (ACK or NACK) corresponding to the reception result of the data signal in steps S807 and S808 to the transmitter 210 (step S809). Further, receiver 220 determines F and ΔF based on the measurement result of the pilot signal received from transmitter 210 after step S801 (step S810). The determination of F and ΔF in step S810 is the same as the determination of F and ΔF in step S802, for example.

Next, the receiver 220 transmits each piece of information indicating F and ΔF determined in step S810 to the transmitter 210 (step S811). Transmission of each information by step S811 can be performed using the RRC message from the receiver 220 to the transmitter 210, for example.

Next, it is assumed that new data or retransmission data to be transmitted to the receiver 220 is generated in the transmitter 210 (step S812). For example, if NACK is transmitted from the receiver 220 to the transmitter 210 in step S809, retransmission data is generated in step S812. If ACK is transmitted from the receiver 220 to the transmitter 210 in step S809 and new data to be transmitted to the receiver 220 is input to the transmitter 210, new data is generated in step S812.

Steps S813 to S815 are the same as steps S807 to S809. However, in step S813, the transmitter 210 transmits a data signal using F indicated by the information received in step S811. In step S814, the transmitter 210 transmits a data signal using F1 = F + ΔF based on F and ΔF indicated by the information received in step S811.

Note that the receiver 220 does not have to determine F in step S810. In this case, the receiver 220 may not transmit information indicating F in step S811. In this case, the transmitter 210 transmits the data signal in steps S813 and S814 using F indicated by the information received in step S803 and ΔF indicated by the information received in step S811.

(Processing by the transmitter according to the first embodiment)
FIG. 9 is a flowchart of an example of processing performed by the transmitter according to the first embodiment. The transmitter 210 according to the first embodiment executes, for example, each step shown in FIG. First, the transmitter 210 starts transmitting a pilot signal (step S901). Step S901 is executed, for example, when the pilot signal generation unit 306 generates a pilot signal and outputs the pilot signal to the multiplexing units 308a and 308b.

Next, the transmitter 210 receives information indicating CQI, F, and ΔF from the receiver 220 (step S902). Step S902 is executed by monitoring the control signal received by the reception control signal processing unit 303, for example.

Next, the transmitter 210 determines F1, T2, and Nmax (the number of continuous automatic transmissions), and transmits information indicating the determined F1, T2, and Nmax to the receiver 220 (step S903). Step S903 is executed by the transmission control unit 304 and the control signal generation unit 307, for example. For example, the transmission control unit 304 determines F1 (= F + ΔF) based on F and ΔF indicated by each piece of information received in step S902. Further, transmission control section 304 determines T2 and Nmax based on the CQI received in step S902, for example. Control signal generating section 307 outputs a control signal including F1, T2, and Nmax determined by transmission control section 304 to multiplexing sections 308a and 308b.

Next, the transmitter 210 determines whether or not data to be transmitted to the receiver 220 is generated (step S904), and waits until data to be transmitted to the receiver 220 is generated (step S904: No loop). ). Step S904 is executed, for example, when the transmission control unit 304 monitors the data signal input to the data signal generation unit 305.

In step S904, when data to be transmitted to the receiver 220 is generated (step S904: Yes), the transmitter 210 sets N to “0” (step S905). N is information stored in a memory (eg, the memory 502) of the transmitter 210. Step S905 is executed by the transmission control unit 304, for example.

Next, the transmitter 210 transmits a data signal and a control signal to the receiver 220 (step S906). Step S906 is executed by, for example, the transmission control unit 304, the data signal generation unit 305, and the control signal generation unit 307. Next, the transmitter 210 increments N (N = N + 1) (step S907). Step S907 is executed by the transmission control unit 304, for example. Next, the transmitter 210 determines whether or not N has reached Nmax determined in step S903 (step S908). Step S908 is executed by the transmission control unit 304, for example.

In step S908, when N has not reached Nmax (step S908: No), the transmitter 210 returns to step S906 and retransmits the data signal and the control signal to the receiver 220. At this time, transmitter 210 retransmits the data signal and the control signal to receiver 220 with a time interval of T2 determined in step S903 from the previous transmission of the data signal and control signal in step S906.

In step S908, when N reaches Nmax (step S908: Yes), the transmitter 210 receives an ACK or NACK for the data signal transmitted in step S906 from the receiver 220 (step S909). Step S909 is executed by monitoring the control signal received by the reception control signal processing unit 303, for example.

Next, the transmitter 210 determines whether or not the response signal received in step S909 is ACK (step S910). Step S910 is executed by, for example, the transmission control unit 304. When it is not ACK (step S910: No), the transmitter 210 moves to step S905. When it is ACK (step S910: Yes), the transmitter 210 moves to step S904.

(Processing by the receiver according to the first embodiment)
FIG. 10 is a flowchart of an example of processing performed by the receiver according to the first embodiment. The receiver 220 according to the first embodiment executes, for example, each step shown in FIG. First, the receiver 220 receives and measures a pilot signal from the transmitter 210 (step S1001). Step S1001 is executed by, for example, reception pilot signal processing section 406 and radio section characteristic evaluation section 407.

Next, receiver 220 determines CQI, F, and ΔF based on the measurement result of the pilot signal in step S1001, and transmits information indicating the determined CQI, F, and ΔF to transmitter 210 (step S1002). ). Step S1002 is executed by, for example, the wireless section characteristic evaluation unit 407 and the control signal generation unit 408. For example, radio section characteristic evaluation unit 407 determines CQI, F, and ΔF based on the measurement result of the pilot signal, and outputs the determined CQI, F, and ΔF to control signal generation unit 408. The control signal generation unit 408 generates a control signal including CQI, F, and ΔF output from the wireless section characteristic evaluation unit 407, and outputs the generated control signal to the RF transmission unit 410.

Next, the receiver 220 receives information indicating F1, T2, Nmax, F, and ΔF from the transmitter 210 (step S1003). Step S1003 is executed, for example, by monitoring the control signal received by the wireless section characteristic evaluation unit 407. Next, the receiver 220 starts monitoring the received signal from the transmitter 210 (step S1004). Step S1004 is executed, for example, when the reception data signal processing unit 403 and the reception control signal processing unit 409 start monitoring the signal output from the RF reception unit 402.

Next, the receiver 220 sets N and A to “0” (step S1005). N and A are information stored in a memory (eg, memory 602) of receiver 220, for example. Step S1005 is executed by the received data signal processing unit 403, for example. Next, the receiver 220 determines whether there is received data from the transmitter 210 based on the monitoring result started in step S1004 (step S1006). Wait until it is determined that there is received data (step S1006: No loop). Step S1006 is executed by at least one of the reception data signal processing unit 403 and the reception control signal processing unit 409.

If it is determined in step S1006 that there is received data (step S1006: Yes), the receiver 220 increments N (N = N + 1) (step S1007). Step S1007 is executed by the received data signal processing unit 403.

Next, the receiver 220 decodes the received data from the transmitter 210 determined to be present in step S1006 (step S1008). Step S1008 is executed, for example, when the reception data signal processing unit 403 performs a decoding process based on the MCS value from the reception control signal processing unit 409.

Next, the receiver 220 determines whether or not the received data has been successfully decoded in step S1008 (step S1009). Step S1009 is executed by the received data signal processing unit 403, for example. If the decoding is successful (step S1009: Yes), the receiver 220 sets A to “1” (step S1010). Step S1010 is executed by received data signal processing section 403, for example.

Next, the receiver 220 determines whether or not N has reached Nmax received from the transmitter 210 in step S1003 (step S1011). Step S1011 is executed by the received data signal processing unit 403, for example. If N has not reached Nmax (step S1011: No), the receiver 220 proceeds to step S1006. If N has reached Nmax (step S1011: Yes), the receiver 220 determines whether A is “1” (step S1012). Step S1011 is executed by the received data signal processing unit 403, for example.

In step S1012, when A is “1” (step S1012: Yes), the receiver 220 transmits ACK to the transmitter 210 (step S1013), and proceeds to step S1001. Step S1013 is executed by the ACK / NACK signal generation unit 405, for example. When A is not “1” (step S1012: No), the receiver 220 transmits a NACK to the transmitter 210 (step S1014), and proceeds to step S1001. Step S1014 is executed by the ACK / NACK signal generation unit 405, for example.

In step S1009, when decoding is not successful (step S1009: No), the receiver 220 determines whether N is greater than 1 (step S1015). Step S1015 is executed by received data signal processing section 403, for example. When N is not larger than 1 (step S1015: No), it can be determined that the immediately preceding received data is the first transmission data. In this case, the receiver 220 stores the previous received data in the received data signal buffer 404 (buffer) (step S1016), and proceeds to step S1011. Step S1016 is executed by received data signal processing section 403, for example.

In step S1015, if N is greater than 1 (step S1015: Yes), it can be determined that the immediately preceding received data is retransmission data. In this case, the receiver 220 synthesizes and decodes the immediately previous received data and the data (data in the buffer) in the received data signal buffer 404 (step S1017). Step S1017 is executed by received data signal processing section 403, for example.

Next, the receiver 220 determines whether or not the decoding in step S1017 is successful (step S1018). Step S1018 is executed by received data signal processing section 403, for example. When the decoding is not successful (step S1018: No), the receiver 220 proceeds to step S1011. When the decoding is successful (step S1018: Yes), the receiver 220 sets A to “1” (step S1019), and proceeds to step S1011. Step S1019 is executed by received data signal processing section 403, for example.

(Determination of F and ΔF by the receiver according to the first embodiment)
FIG. 11 and FIG. 12 are diagrams illustrating an example of determination of F and ΔF by the receiver according to the first embodiment. In FIG. 11, the horizontal axis represents time, and the vertical axis represents received power at the receiver 220. Delay waves 1101 to 1104 indicate delay waves received by the receiver 220 in pilot signals transmitted from the transmitter 210 to the receiver 220. For example, the receiver 220 acquires the dispersion characteristics of the pilot signal in the time domain based on the measurement results of the delay waves 1101 to 1104.

12, the horizontal axis indicates the frequency, and the vertical axis indicates the received power at the receiver 220. The frequency dispersion characteristic 1200 is a dispersion characteristic in the frequency domain of a pilot signal transmitted from the transmitter 210 to the receiver 220. The receiver 220 can obtain the frequency dispersion characteristic 1200 by Fourier-transforming the dispersion characteristic in the time domain of the pilot signal acquired based on the measurement results of the delay waves 1101 to 1104 shown in FIG.

Further, the receiver 220 detects a plurality of coherent bands 1211 to 1214 in the frequency dispersion characteristic 1200. Then, the receiver 220 calculates the bandwidth of the coherent bandwidths 1211-1124,..., That is, the average value and deviation of the coherent bandwidth (Coherent Bandwidth). In addition, the receiver 220 determines F and ΔF based on the calculated average value and deviation of the coherent bandwidth.

11 and 12, the receiver 220 determines F and ΔF based on the coherent bandwidth of the pilot signal received from the transmitter 210, for example. For example, the receiver 220 may calculate F and F based on the average value and deviation of the coherent bandwidth of the pilot signal from the transmitter 210 calculated from the frequency dispersion characteristic 1200 of the received power of the delayed waves 1101 to 1104 of the received pilot signal. ΔF is determined. Thereby, F and ΔF that increase the effect of frequency interval diversity can be determined.

Thus, according to the first embodiment, at time t1, the same data signal can be transmitted by each of the frequency f_1 and the frequency f_2 having the frequency interval F. Also at time t2, it is possible to transmit the same data signal at each of frequency f_1 and frequency f_3 having the frequency interval F1 = F + ΔF. Thereby, the receiving characteristic (for example, BER) in the 2nd radio | wireless apparatus 120 can be improved by each diversity effect of a frequency diversity, a time diversity, and a frequency space | interval diversity.

Further, for example, even if the interval (T2) between the time t1 and the time t2 is reduced in order to reduce the transmission delay, the decrease in the effect of time diversity can be compensated for by the frequency interval diversity. Thereby, it is possible to reduce transmission delay while suppressing deterioration of reception characteristics. For this reason, for example, it is possible to realize a wireless system that satisfies the requirements of reliability and delay amount required by URLLC.

(Diversity transmission by the transmitter according to the first embodiment (Nmax = 3))
FIG. 13 is a diagram illustrating an example of diversity transmission (Nmax = 3) by the transmitter according to the first embodiment. In FIG. 13, the horizontal axis indicates time, and the vertical axis indicates frequency. FIG. 13 illustrates a case where the number of times that the transmitter 210 continuously transmits the data signal to the receiver 220 (continuous automatic transmission number Nmax) is three.

The transmitter 210 wirelessly transmits data signals 1311, 1312, 1321, 1322, 1331, and 1332 to the receiver 220, for example. Data signals 1311, 1312, 1321, 1322, 1331, and 1332 are all data signals indicating the same data.

Data signals 1311 and 1312 are data signals transmitted at the same time t1. Data signals 1321 and 1322 are data signals transmitted at the same time t2. Data signals 1331 and 1332 are data signals transmitted at the same time t3. Data signals 1311, 1321, and 1331 are data signals transmitted at the reference frequency f_1. The data signal 1312 is a data signal transmitted at a frequency f_2 whose frequency interval with the reference frequency f_1 is F. Data signals 1322 and 1332 are data signals transmitted at a frequency f_3 having a frequency interval F1 from the reference frequency f_1.

Also, each time interval between the time t1 when the data signals 1311 and 1312 are transmitted, the time t2 when the data signals 1321 and 1322 are transmitted, and the time t3 when the data signals 1331 and 1332 are transmitted is T2. To do. In this case, the time interval T2 × 2 is set to a sufficiently small value with respect to, for example, an allowable transmission delay amount (for example, 1 [ms]).

As in the example shown in FIG. 13, time diversity in which the same data signal is transmitted three times may be used. In the example illustrated in FIG. 13, the frequency interval between the data signals 1321 and 1322 and the frequency interval between the data signals 1331 and 1332 are the same F1, but the configuration is not limited thereto. For example, the frequency interval between the data signals 1331 and 1332 may be the same F as the frequency interval of the data signals 1311 and 1312. Further, the frequency interval between the data signals 1331 and 1332 may be F2 which is different from F and F1.

Also, the number of times that the transmitter 210 transmits the same data signal is not limited to two times (for example, see FIG. 7) or three times (for example, see FIG. 13), and can be any number of two or more. However, the sum of the time intervals of the transmission of the same data signal by the transmitter 210 a plurality of times is set to a sufficiently small value with respect to an allowable transmission delay amount (for example, 1 [ms]).

(Embodiment 2)
In the second embodiment, parts different from the first embodiment will be described. Although the configuration in which receiver 220 determines F and ΔF has been described in Embodiment 1, the configuration in which transmitter 210 determines F and ΔF will be described in Embodiment 2.

(Processing by the low-delay transmission system according to the second embodiment)
FIG. 14 is a sequence diagram illustrating an example of processing by the low-delay transmission system according to the second embodiment. In the transmitter 210 (for example, a base station) and the receiver 220 (for example, a terminal) of the low-delay transmission system 200 according to the second embodiment, for example, each step shown in FIG. 14 is executed.

The bidirectional communication between the transmitter 210 and the receiver 220 shown in FIG. 14 is executed by, for example, TDD. In this case, the same frequency is used for transmission of a radio signal from the transmitter 210 to the receiver 220 and transmission of a radio signal from the receiver 220 to the transmitter 210. Therefore, the transmitter 210 can estimate the reception quality of the pilot signal from the transmitter 210 at the receiver 220 based on the measurement result of the pilot signal from the receiver 220.

First, the receiver 220 wirelessly transmits a pilot signal to the transmitter 210 (step S1401). Receiver 220 continues to transmit the pilot signal to transmitter 210 continuously after step S1401. Next, the transmitter 210 determines F1, T2, Nmax, F, and ΔF based on the measurement result of the pilot signal received in step S1401 (step S1402). The determination method of F and ΔF based on the measurement result of the pilot signal by the transmitter 210 is the same as the determination method of F and ΔF based on the measurement result of the pilot signal by the receiver 220 described above, for example. Further, based on the determined F and ΔF, the transmitter 210 calculates F1 by F1 = F + ΔF. The method for determining T2 and Nmax by transmitter 210 is the same as the method for determining T2 and Nmax by receiver 220 described above, for example. In the example shown in FIG. 14, it is assumed that 2 is determined as Nmax.

Next, the transmitter 210 transmits information indicating F1, T2, Nmax, F, and ΔF determined in step S1402 to the receiver 220 (step S1403). The transmission in step S1403 can be executed using, for example, an RRC message from the transmitter 210 to the receiver 220. As described above, since F1 = F + ΔF, the transmitter 210 may not transmit information indicating any one of F1, F, and ΔF to the receiver 220.

Steps S1404 to S1407 shown in FIG. 14 are the same as steps S806 to S809 shown in FIG. However, in step S1405, the transmitter 210 transmits a data signal using the F determined in step S1402 at the reference frequency f_1 and the frequency f_2 whose frequency interval between the frequencies f_1 is F ( Frequency interval F). On the other hand, the receiver 220 receives the data signal transmitted at the frequency interval F using F indicated by the information received in step S1403.

In step S1406, transmitter 210 transmits a data signal at reference frequency f_1 and frequency f_3 using F1 = F + ΔF based on F and ΔF determined in step S1402 (frequency interval F1). On the other hand, the receiver 220 is transmitted at the frequency interval F1 using F1 (= F + ΔF) calculated from F and ΔF indicated by the information received at step S1403 or F1 indicated by the information received at step S1403. Receive data signals.

Steps S1408 to S1411 shown in FIG. 14 are the same as steps S812 to S815 shown in FIG.

Further, after step S1407, the transmitter 210 may newly determine F and ΔF based on the measurement result of the pilot signal received from the receiver 220 after step S1401. The determination of F and ΔF is the same as the determination of F and ΔF in step S1402, for example. In this case, the transmitter 210 transmits a data signal using F and ΔF newly determined in steps S1409 and S1410.

Further, after step S1407, the transmitter 210 may newly determine ΔF based on the measurement result of the pilot signal received from the receiver 220 after step S1401. This determination of ΔF is the same as the determination of ΔF in step S1402, for example. In this case, the transmitter 210 transmits a data signal using F determined in step S1402 and the newly determined ΔF in steps S1409 and S1410.

(Processing by the transmitter according to the second embodiment)
FIG. 15 is a flowchart of an example of processing performed by the transmitter according to the second embodiment. The transmitter 210 according to the second embodiment executes, for example, each step illustrated in FIG. First, the transmitter 210 receives and measures a pilot signal from the receiver 220 (step S1501). Next, transmitter 210 determines F1, T2, Nmax, F and ΔF based on the measurement result of the pilot signal in step S1501, and receives each information indicating the determined F1, T2, Nmax, F and ΔF. It transmits to the machine 220 (step S1502).

Steps S1503 to S1509 shown in FIG. 15 are the same as steps S904 to S910 shown in FIG. However, in step S1507, the transmitter 210 determines whether N has reached Nmax determined in step S1502.

(Processing by the receiver according to the second embodiment)
FIG. 16 is a flowchart of an example of processing performed by the receiver according to the second embodiment. The receiver 220 according to the second embodiment executes, for example, each step illustrated in FIG. First, the receiver 220 starts transmitting a pilot signal to the transmitter 210 (step S1601). Steps S1602 to S1618 shown in FIG. 16 are the same as steps S1003 to S1019 shown in FIG.

Thus, according to the second embodiment, even in the configuration in which transmitter 210 determines F and ΔF, similarly to the first embodiment, it is possible to reduce the transmission delay while suppressing the deterioration of the reception characteristics. .

As described above, according to the wireless device, the wireless system, and the processing method, it is possible to reduce transmission delay while suppressing deterioration of reception characteristics.

For example, when the variation factors of the characteristics of a certain radio section are a plurality of different types of causes (for example, Doppler shift, presence of a delayed wave with a long time length, multipath, etc.), combining different types of diversity transmission methods, The resistance to fluctuations in the characteristics of the radio section is increased. For this reason, the stability of transmission of a radio signal increases.

For example, in an environment with many multipaths such as an urban area, fluctuations in radio reception characteristics in the frequency domain become large. This is because when a receiver receives multipaths transmitted through different paths, amplitude changes due to phase differences between the multipaths, and the effect of the phase differences appears depending on the frequency. The change in the amplitude due to the phase difference between the multipaths is caused by, for example, canceling out the amplitudes in the case of reverse-phase synthesis reception. In addition, as the number of multipaths increases, the variation in radio reception characteristics in the frequency domain becomes more complicated.

In such an environment, the effect of frequency diversity is increased. However, the characteristics (for example, reception amplitude at the receiver) may deteriorate at the same time at a plurality of frequencies used for transmission. For this reason, for example, it is conceivable to combine frequency diversity with time diversity that provides diversity in the time domain. For example, wireless communication between a base station and an automobile is strongly affected by both Doppler shift and multipath. For this reason, for example, a large diversity gain can be obtained by applying a combination of frequency diversity and time diversity to wireless communication between a base station and an automobile.

However, transmission by time diversity is not suitable for application where low-delay transmission is required because the transmission delay of a radio signal increases. On the other hand, if the time interval for transmitting a radio signal is shortened in time diversity, there is a problem in that although transmission delay is reduced, diversity gain is reduced.

On the other hand, according to each embodiment described above, when data signals are continuously transmitted by frequency diversity (time diversity transmission), for example, the frequency interval is changed between the first transmission and the second transmission. Thereby, diversity can be given to the frequency interval, and diversity gain can be increased. Therefore, even if the time interval for transmitting radio signals in time diversity is shortened, the reduction in diversity gain can be suppressed. For this reason, it is possible to reduce transmission delay while suppressing deterioration of reception characteristics.

DESCRIPTION OF SYMBOLS 100 Radio system 110 1st radio | wireless apparatus 111 Transmitter 112,122 Control part 120 2nd radio | wireless apparatus 121 Receiver 200 Low-delay transmission system 210 Transmitter 220 Receiver 301,310,401,411 Antenna 302,402 RF receiver 303 , 409 Reception control signal processing section 304 Transmission control section 305 Data signal generation section 306 Pilot signal generation section 307, 408 Control signal generation section 308a, 308b, 308c Multiplexing section 309, 410 RF transmission section 311 Retransmission control section 403 Reception data signal processing Unit 404 reception data signal buffer 405 ACK / NACK signal generation unit 406 reception pilot signal processing unit 407 radio section characteristic evaluation unit 500,600 communication device 501 601 CPU
502, 602 Memory 503, 604 Wireless communication interface 504 Wired communication interface 509, 609 Bus 603 User interface 711, 712, 721, 722, 1311, 1312, 1321, 1322, 1331, 1332 Data signal 1101-1104 Delay wave 1200 Frequency dispersion Characteristics 1211-1214 ... Coherent bandwidth

Claims (10)

1. A transmitter capable of transmitting a data signal to another wireless device;
   The transmitting unit transmits the data signal at each of a first frequency and a second frequency having a first interval in a first time, and the first interval in a second time different from the first time. A control unit for transmitting the data signal at each of a third frequency and a fourth frequency having a second interval different from each other;
   A wireless device comprising:
2. The control unit causes the transmission unit to transmit information capable of specifying the first frequency, the second frequency, the third frequency, and the fourth frequency to the other wireless device. The wireless device according to claim 1.
3. The third frequency is the same frequency as the first frequency,
   The control unit, for the transmission unit, information indicating the first frequency, information indicating the first interval, information indicating the second interval or between the first interval and the second interval Transmitting information indicating the difference to the other wireless device,
   The wireless device according to claim 1, wherein the wireless device is a wireless device.
4. 4. The control unit according to claim 1, wherein the control unit causes the transmission unit to transmit information capable of specifying the first time and the second time to the other radio device. A wireless device according to 1.
5. The first interval and the second interval are each interval based on a coherent bandwidth of a radio signal received by the other radio device from its own device. The wireless device described.
6. The first interval and the second interval are averages of coherent bandwidths of the radio signals calculated from dispersion characteristics in the frequency domain of the received power of delayed waves of radio signals received from the other devices by the other radio devices. The radio apparatus according to claim 5, wherein each interval is based on a value and a deviation.
7. A receiver capable of receiving data signals from other wireless devices;
   In the first time, the receiving unit receives the data signal transmitted by each of the first frequency and the second frequency having a first interval, and in the second time different from the first time, A control unit for receiving the data signal transmitted by each of the third frequency and the fourth frequency having a second interval different from the first interval;
   A wireless device comprising:
8. A first wireless device capable of transmitting a data signal to another wireless device, wherein the data signal is transmitted at each of a first frequency and a second frequency having a first interval in a first time, A first wireless device for transmitting the data signal at each of a third frequency and a fourth frequency having a second interval different from the first interval at a second time different from one hour;
   A second wireless device capable of receiving the data signal from the first wireless device, receiving the data signal transmitted at each of the first frequency and the second frequency in the first time; A second wireless device for receiving the data signal transmitted at each of the third frequency and the fourth frequency at the second time;
   A wireless system comprising:
9. A wireless device capable of transmitting data signals to other wireless devices
   Transmitting the data signal at each of a first frequency and a second frequency having a first interval with each other at a first time;
   Transmitting the data signal at each of a third frequency and a fourth frequency having a second interval different from the first interval in a second time different from the first time;
   A processing method characterized by the above.
10. A wireless device capable of receiving data signals from other wireless devices
    Receiving the data signal transmitted at each of a first frequency and a second frequency having a first interval with each other at a first time;
    Receiving the data signal transmitted at each of a third frequency and a fourth frequency having a second interval different from the first interval at a second time different from the first time;
    A processing method characterized by the above.

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