WO2018016121A1 - Dispositif de communication, procédé de commande et programme - Google Patents

Dispositif de communication, procédé de commande et programme Download PDF

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Publication number
WO2018016121A1
WO2018016121A1 PCT/JP2017/009935 JP2017009935W WO2018016121A1 WO 2018016121 A1 WO2018016121 A1 WO 2018016121A1 JP 2017009935 W JP2017009935 W JP 2017009935W WO 2018016121 A1 WO2018016121 A1 WO 2018016121A1
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WO
WIPO (PCT)
Prior art keywords
ofdm signal
timing
signal
symbol
ofdm
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PCT/JP2017/009935
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English (en)
Japanese (ja)
Inventor
和秀 戸田
昌也 柴山
和也 森脇
典征 橋本
トマス ブルジョア
恭宏 末柄
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Kddi株式会社
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Publication of WO2018016121A1 publication Critical patent/WO2018016121A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes

Definitions

  • the present invention relates to a communication device, a control method, and a program, and specifically relates to an interference control technique in a wireless communication system.
  • Non-Patent Document 1 a communication system using an orthogonal frequency division multiplexing (OFDM) signal that does not use a cyclic prefix.
  • a next-generation communication method signal may be transmitted on a different frequency channel in the same frequency band as a current-generation communication method signal using an OFDM signal using a cyclic prefix. is assumed. Further, it can be assumed that an OFDM signal using a cyclic prefix and an OFDM signal not using a cyclic prefix coexist in the same frequency band as a signal of the next generation communication method.
  • the receiving device simultaneously executes demodulation processing of a plurality of OFDM signals included in the same frequency band received in the same time interval.
  • the receiving apparatus may receive the first OFDM signal using the cyclic prefix and the second OFDM signal not using the cyclic prefix at the same time.
  • the receiving apparatus demodulates the first OFDM signal.
  • the receiving apparatus executes a receiving process in which the cyclic prefix is removed from the first OFDM signal and discrete Fourier transform is performed.
  • the receiving apparatus receives the second OFDM signal at the same time as the first OFDM signal, and simultaneously with the reception processing of the first OFDM signal, the first OFDM signal is also received from the second OFDM signal. The reception process is executed.
  • the second OFDM signal after the cyclic prefix removal loses orthogonality, and as a result, the first OFDM signal is lost. It can interfere with the OFDM signal.
  • the present invention generates an OFDM signal that does not use a cyclic prefix that does not interfere with the OFDM signal that uses a cyclic prefix.
  • a communication apparatus provides a second OFDM signal that does not use a cyclic prefix while another apparatus transmits a first orthogonal frequency division multiplexing (OFDM) signal that uses a cyclic prefix.
  • OFDM orthogonal frequency division multiplexing
  • the accompanying drawings are included in the specification, constitute a part thereof, show an embodiment of the present invention, and are used to explain the principle of the present invention together with the description.
  • FIG. 1 is a diagram illustrating a configuration example of a wireless communication system according to the present embodiment.
  • the wireless communication system of FIG. 1 includes, for example, two transmission devices and two reception devices. This is only an example, and there may be three or more transmission devices and only one reception device.
  • a first transmitter transmits a first orthogonal frequency division multiplexing (OFDM) signal using a cyclic prefix (CP), and a second transmitter transmits a second OFDM signal that does not use a CP. Shall be sent.
  • the first receiving apparatus is a receiving apparatus that is the destination of the first OFDM signal, and receives the first OFDM signal and the second OFDM signal at the same time.
  • OFDM orthogonal frequency division multiplexing
  • CP cyclic prefix
  • the first receiving apparatus is a receiving apparatus that is the destination of the first OFDM signal, and receives the first OFDM signal and the second OFDM signal at the same time.
  • the second receiving apparatus is a receiving apparatus that is the destination of the second OFDM signal. Although omitted in FIG. 1, the second receiving apparatus can receive the first OFDM signal together with the second OFDM signal.
  • one of the transmitting device and the receiving device may be a base station device and the other may be a mobile unit or a fixed terminal device, but both may be terminal devices, and the present invention is not limited to these examples.
  • the OFDM signal here refers to all signals using carriers orthogonal to each other, and is a concept including DFT-S-OFDM (DFT spread OFDM) and the like.
  • the wireless communication system of FIG. 1 is a time synchronization system, but is not limited thereto.
  • the second transmission apparatus can control the second OFDM signal according to the information regarding the timing of the window for removing the CP of the first OFDM signal in the first reception apparatus
  • Asynchronous systems can be used.
  • the window for removing the CP refers to a time interval in which the receiving apparatus extracts a component in the time domain to be subjected to Fourier transform.
  • the first OFDM signal and the second OFDM signal can be transmitted simultaneously by frequency division multiplexing in one of frequency bands such as an 800 MHz band, a 2 GHz band, and a 3 to 4 GHz band, for example.
  • the receiving device collectively receives signals in the same frequency band.
  • the first receiving apparatus since the first receiving apparatus is an apparatus that receives the first OFDM signal, the first receiving apparatus removes the CP by removing the CP in each of one or more symbols included in the first OFDM signal. A discrete Fourier transform (DFT) is performed on the later symbols.
  • DFT discrete Fourier transform
  • the first receiving apparatus may simultaneously receive the second OFDM signal in the same frequency band.
  • CP removal which is processing in the time domain, is also executed for the second OFDM signal. It becomes. That is, the second OFDM signal is subjected to DFT after the signal component in the section corresponding to the CP of the first OFDM signal is removed.
  • the orthogonality originally secured is lost, and the frequency component of the second OFDM signal leaks into the adjacent frequency band. It may interfere with the first OFDM signal that has been separated on the axis.
  • FIGS. 2A and 2B This is due to the discontinuity of the component of the second OFDM signal at the start timing and end timing of the window.
  • FIGS. 2A and 2B This state is schematically shown in FIGS. 2A and 2B.
  • the first OFDM signal and the second OFDM signal are transmitted in the radio section without frequency components overlapping each other by frequency division multiplexing.
  • the second OFDM signal does not interfere with the first OFDM signal in the radio section.
  • the amplitude at the start timing and end timing of the symbols of the second OFDM signal is continuous.
  • FIG. 2B when the first OFDM signal receiving apparatus removes the CP, the time interval component corresponding to the CP of the second OFDM signal is simultaneously removed.
  • the amplitude of the second OFDM signal becomes discontinuous, the frequency component of the second OFDM signal spreads, and interferes with the first OFDM signal.
  • the second transmission apparatus in order to prevent such interference, the second transmission apparatus generates the second OFDM signal so as to suppress the above-described discontinuity.
  • the second OFDM signal is obtained by band-limiting the OFDM signal with a predetermined filter, and has the same time length as the first OFDM signal. Then, it is assumed that the first OFDM signal and the second OFDM signal are transmitted in synchronization. At this time, if the end timing of the window used for CP removal in the reception processing of the first OFDM signal is the boundary between two symbols of the main wave of the first OFDM signal, The amplitude of the main wave of the second OFDM signal is (almost) zero. Therefore, in this case, as indicated by 301 in FIG.
  • the second transmission device sets the amplitude of the second OFDM signal at the start timing of the window in the reception process at the first reception device to a sufficiently small predetermined value. Make the following (almost zero). Thereby, even if some signal components are removed by CP removal of the first OFDM signal, continuity of the signal is ensured in the second OFDM signal, and as a result, the frequency of the second OFDM signal is increased. The amount of components leaking into adjacent frequency bands is reduced.
  • the reception amplitude of the second OFDM signal in the first receiving device may not be (nearly) zero at the above-described window end timing.
  • the second transmission apparatus is configured so that the reception amplitude of the second OFDM signal in the first reception apparatus is not more than a predetermined value that is sufficiently small at the window end timing. Signal generation may be performed.
  • the second transmission apparatus can generate the second OFDM signal so that the reception amplitude at the first reception apparatus is equal to or less than a predetermined value only at the start timing or end timing of the window described above.
  • the second transmitting apparatus is the first receiving apparatus in the interval after the period of the symbol preceding the symbol before the start timing of the window related to the symbol.
  • the second OFDM signal may be generated so that the reception amplitude is a predetermined value or less.
  • the second transmitting apparatus is the first receiving apparatus in the section before the symbol period after the symbol after the end timing of the window for the certain symbol.
  • the second OFDM signal may be generated so that the reception amplitude is a predetermined value or less.
  • FIG. 4 shows a hardware configuration example of the second transmission device described above.
  • the second transmission device is referred to as a transmission device when there is no particular limitation.
  • the transmission device has a hardware configuration as shown in FIG. 4, and includes, for example, a CPU 401, a ROM 402, a RAM 403, an external storage device 404, and a communication device 405.
  • the CPU 401 executes a program that realizes each function of the second transmission device described above, which is recorded in any of the ROM 402, the RAM 403, and the external storage device 404.
  • the CPU 401 is an example of a processor, and may be replaced by another processor such as an ASIC (application-specific integrated circuit), or may be replaced by a reconfigurable processor such as an FPGA (field programmable gate array). Also good.
  • ASIC application-specific integrated circuit
  • FPGA field programmable gate array
  • a transmission apparatus controls the communication apparatus 405 by CPU401, for example, and communicates with another apparatus.
  • the communication device 405 can transmit at least an OFDM signal that does not use a CP, and can also receive a signal.
  • the communication device 405 transmits an OFDM signal using a CP or a signal of another wireless communication method. And may be configured to receive.
  • the communication device 405 may be capable of transmitting signals in a plurality of frequency bands as well as in one frequency band. For example, both a cellular communication method and a wireless LAN communication method may be used. .
  • the communication device 405 may be configured to perform wired communication.
  • the transmission apparatus is schematically illustrated as having one communication apparatus 405, but is not limited thereto.
  • the transmission device may include a first communication device for cellular communication and a second communication device for wireless LAN communication. Further, the transmission device may have separate communication devices for wired communication and wireless communication.
  • the transmission apparatus may include dedicated hardware for executing each function, or may execute other parts with a computer that executes a part of the hardware and operates the program. Further, all functions of the transmission device may be executed by a computer and a program.
  • FIG. 5 is a diagram illustrating a functional configuration example of the transmission apparatus according to the present embodiment.
  • the transmission apparatus includes a transmission unit 501, a reception unit 502, a timing acquisition unit 503, and a signal generation unit 504.
  • the transmission device may have functions (not shown) such as various functions of information processing equipment including the transmission device, for example, and has at least a function of either a base station device or a terminal device in cellular communication. Shall.
  • the transmission unit 501 transmits the above-described second OFDM signal generated by the signal generation unit 504 described later.
  • the transmission unit 501 includes, for example, an antenna and a circuit used for outputting a radio signal via the antenna.
  • the receiving unit 502 receives a radio signal transmitted from another device.
  • the receiving unit 502 includes, for example, an antenna and a circuit for processing a radio signal received via the antenna and extracting data. Note that the transmission unit 501 and the reception unit 502 can share one or more antennas and circuits.
  • the timing acquisition unit 503 acquires information on at least one of the start timing and the end timing of the window used when removing the CP in the first OFDM signal receiving apparatus.
  • the downlink signal can be transmitted synchronously between the base stations, so that the end timing of the CP portion when the terminal itself transmits the first OFDM signal is It can be specified as the start timing.
  • the transmission apparatus can specify the symbol boundary as the window end timing.
  • the timing of this window can be specified regardless of whether or not the transmission apparatus actually transmits the first OFDM signal.
  • the transmission apparatus can estimate the timing of the above-described window related to the first OFDM signal based on, for example, a timing advance signal received from the base station apparatus.
  • the transmitting apparatus may assume that the second OFDM signal transmitted by itself is received by the base station apparatus in synchronization with the first OFDM signal transmitted by another apparatus by the timing advance signal. it can. For this reason, the transmitting apparatus assumes that one or more symbols of the second OFDM signal transmitted by itself are received at the same timing as the symbols of the first OFDM signal, and ends the CP of the first OFDM signal.
  • the timing may be estimated as the window start timing.
  • the transmission apparatus may estimate the symbol boundary of the first OFDM signal as the window end timing.
  • the transmitting device acquires information specifying the window timing directly or indirectly from the receiving device that is the partner device of its own communication. Also good. Further, for example, the second transmission device may acquire information related to window timing from the first transmission device.
  • the signal generation unit 504 generates a second OFDM signal based on the information about the window timing in the first OFDM signal receiving apparatus acquired by the timing acquisition unit 503. Specifically, as described above, the signal generation unit 504 has a predetermined reception amplitude of the second OFDM signal in the first OFDM signal receiving apparatus at at least one of the start timing and the end timing of the window. A second OFDM signal is generated so as to be less than or equal to the value. Note that the signal generation unit 504 may set the above-described reception amplitude to be equal to or less than a predetermined value in a section before the start timing of the window and after the end timing of the previous symbol section.
  • the signal generation unit 504 may make the above-described reception amplitude equal to or less than a predetermined value in a section after the start timing of the window and after the start timing of the subsequent symbol section. Further, the signal generation unit 504 includes the first and second reception amplitudes so as to be equal to or less than a predetermined value in a predetermined length section determined based on a delay profile, for example, including at least one of a window start timing and an end timing. Two OFDM signals may be generated.
  • the signal generation unit 504 generates a temporary modulation symbol.
  • the signal generation unit 504 obtains a temporary modulation symbol by mapping a bit string to be transmitted to a point on the IQ plane by a modulation scheme such as QPSK, 16QAM, or 64QAM.
  • the temporary modulation symbol corresponds to a time-domain signal, and is input to a serial / parallel converter (S / P converter) and parallelized, and then input to an M-point DFT (discrete Fourier transformer).
  • S / P converter serial / parallel converter
  • M-point DFT discrete Fourier transformer
  • the signal generation unit 504 generates the reception amplitude when the first OFDM signal receiving apparatus receives the second OFDM signal at a certain timing so that the reception amplitude is a predetermined value or less. . For this reason, the signal generation unit 504 inserts “0” as a transmission symbol corresponding to the certain timing. Therefore, the signal generation unit 504 generates Mh temporary modulation symbols when, for example, h “0” s are inserted.
  • the temporary modulation symbols that are parallelized with “0” inserted in part are converted into frequency domain signals composed of M samples by M-point DFT.
  • the signal converted into the frequency domain signal is input to the UF-OFDM modulator.
  • the input frequency domain signal is distributed and input to a plurality of N-point IDFTs (Inverse Discrete Fourier Transformers).
  • IDFT a frequency domain signal is converted into a time domain signal and output.
  • a plurality of IDFTs correspond to mutually different subbands. For example, when there are B IDFTs, M samples are input to each IDFT, for example, M / B and distributed to B subbands. To be sent.
  • each IDFT is band-limited by a filter of length L and then added and transmitted.
  • the filter can generate an OFDM signal that does not use the CP and has the same time length as the OFDM signal that uses the CP. Since M ⁇ N, not only the output of the M point DFT described above but also a sample related to “0” or another signal is input to at least a part of the N point IDFT.
  • the signal output by the M-point DFT is over-sampled N / M times by passing through the N-point IDFT.
  • the i-th sample input to the M-point DFT is the i ⁇ N / M-th sample in the output of the IDFT. From this, for example, by setting the k ⁇ M / N-th sample among the inputs in the M-point DFT to 0, the amplitude of the k-th sample of the output of the N-point IDFT can be reduced to a predetermined value or less.
  • the sample output by the IDFT is a time-domain signal transmitted as a radio signal after being band-limited by a filter.
  • the signal generation unit 504 considers the influence of the filter so that the amplitude is sufficiently small at the timing based on the information acquired by the timing acquisition unit 503 described above.
  • the position where “0” is inserted is adjusted. For example, when the amplitude of the p-th sample of the final signal is reduced and the filter is delayed by L samples, the (p ⁇ L) ⁇ M / N-th sample among the inputs in the M-point DFT is 0.
  • the signal generation unit 504 has the reception amplitude of the second OFDM signal at or below the predetermined value at the start timing / end timing of the window used when removing the CP.
  • a second OFDM signal can be generated.
  • the transmission apparatus acquires information regarding the timing of the window used for CP removal of the first OFDM signal in the reception apparatus for the first OFDM signal (S701). ).
  • the transmission device can acquire information related to the timing of the window actually used by the reception device of the first OFDM signal by receiving a notification from the reception device.
  • the transmission apparatus may estimate the window timing in the reception apparatus based on, for example, a timing advance signal.
  • the transmitting apparatus can know the timing of the CP of the first OFDM signal when the symbol of the first OFDM signal and the symbol of the second OFDM signal are synchronized, The window timing may be estimated from the timing.
  • the transmission apparatus is configured so that the reception amplitude of the first OFDM signal at the reception apparatus at the start timing and the end timing of the window specified based on the acquired information is equal to or less than a predetermined value.
  • a second OFDM signal is generated (S702). For example, as shown in 301 to 304 in FIG. 3, the transmission apparatus can perform the first operation in an arbitrary form so as to reduce the discontinuity generated in the amplitude of the second OFDM signal at the start timing and the end timing of the window. Two OFDM signals may be generated.
  • the transmission apparatus prevents the second OFDM signal from interfering with the first OFDM signal in the reception / demodulation process of the first OFDM signal, or the amount of interference. Can be made sufficiently small. Therefore, it is possible to suppress degradation in quality and frequency utilization efficiency when the first OFDM signal having CP and the second OFDM signal not having CP are simultaneously transmitted by frequency division multiplexing.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un dispositif de communication permettant de transmettre un second signal OFDM n'utilisant pas de préfixe cyclique pendant qu'un premier signal OFDM utilisant le préfixe cyclique est transmis par un autre dispositif, qui acquiert, dans un dispositif de réception pour le premier signal OFDM, des informations concernant la synchronisation d'une fenêtre utilisée lorsque le préfixe cyclique est retiré du premier signal OFDM, génère un ou plusieurs symboles de transmission du second signal OFDM de manière que l'amplitude dans le dispositif de réception du second signal OFDM atteigne une valeur prédéterminée ou une valeur inférieure à un premier temps où la fenêtre est commencée, et transmet le second signal OFDM comprenant lesdits symboles de transmission générés.
PCT/JP2017/009935 2016-07-22 2017-03-13 Dispositif de communication, procédé de commande et programme WO2018016121A1 (fr)

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JP2016144726A JP2018014687A (ja) 2016-07-22 2016-07-22 通信装置、制御方法及びプログラム
JP2016-144726 2016-07-22

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3139557A1 (fr) * 2015-09-03 2017-03-08 Alcatel Lucent Procédé et appareil pour réduire les interférences entre des signaux ofdm et des signaux filtrés universels à porteuses multiples (ufmc)

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3139557A1 (fr) * 2015-09-03 2017-03-08 Alcatel Lucent Procédé et appareil pour réduire les interférences entre des signaux ofdm et des signaux filtrés universels à porteuses multiples (ufmc)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
NOKIA ET AL.: "Initial uplink performance results for New Radio waveforms below 6 GHz", 3GPP TSG-RAN WG1#85 RL-165013, 23 May 2016 (2016-05-23), Retrieved from the Internet <URL:http://www.3gpp.org/ftp/tsg_ran/WGl_RL1/TSGR1_1122/Docs/R1-165013.zip> *

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