JP2017011350A - System, method and device for radio relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform carrier sense at transfer while performing full duplex relay, to enable transfer processing according to a busy/idle state of a frequency channel.SOLUTION: A transmission station device includes means for dividing a data frame into a plurality of subframe to transmit them. A radio relay device receives the data frame on each subframe basis. The radio relay device includes means for repeating the processing of: performing carrier sense on a frequency channel when one subframe can be received normally; detecting the reception level of a residual after a signal component of the received subframe is canceled from the whole reception signal; and if the reception level is a predetermined threshold or greater, determining the frequency channel is busy, so as to await the transfer of the subframe concerned and receive the next subframe, whereas if the reception level is lower than the threshold, performing processing to transfer inclusive of a subframe having been awaited before that time.SELECTED DRAWING: Figure 1

Description

  According to the present invention, a data frame transmitted from a transmitting station device to a receiving station device via a predetermined frequency channel is received by a wireless relay device, regenerated, and immediately transferred (full-duplex relay) using the frequency channel. The present invention relates to a relay system, a wireless relay device, and a wireless relay method.

FIG. 5 shows a configuration example and problems of a conventional wireless relay system.
In FIG. 5, the wireless relay system is configured to transfer data from a transmitting station (base station) device 51 to a receiving station (terminal station) device 53 via a wireless relay device 52. The wireless relay device 52 immediately performs data reception from the transmission station device 51 and data transmission to the reception station device 53 using full-duplex relay technology (Non-Patent Document 1). At this time, since data reception and data transmission are immediately performed at the same frequency, the wireless relay device 52 performs a wraparound cancellation process for suppressing wraparound.

  Here, when there is a transmission station device 54 and a reception station device 55 of different systems, and the transmission station device 54 operates independently of the system of the transmission station device 51 -the radio relay device 52 -the reception station device 53, the transmission station device 54 transmits May cause interference to the radio relay device 52 and the receiving station device 53. In addition, a signal transmitted by the wireless relay device 52 may interfere with the receiving station device 55.

  For example, the transmitting station device 51 transmits the data frame 1, the wireless relay device 52 receives the data frame 1 and transmits it immediately after the retransmission process, and the receiving station device 53 receives the data frame 1 if normal. . Here, when the wireless relay device 52 starts transmission (transfer) of the data frame 1, since the data frame 1 from the transmission station device 51 is being received, carrier sense cannot be performed.

  On the other hand, when the transmission station device 54 is transmitting the data frame 2 when the wireless relay device 52 starts transmission (transfer) of the data frame 1, the data transmitted by the wireless relay device 52 at the reception station device 53 There is a possibility that the data frame 2 collides between the frame 1 and the transmission station device 54 and the data frame 1 cannot be normally received.

Jung II Choiy, et.al., “Achieving Single Channel, Full Duplex Wireless Communication”, Proceedings of the 16th ACM Annual International Conference on Mobile Computing and Networking, 2010 (MobiCom'10)

  In a conventional wireless relay device, carrier sense cannot be performed when a received signal is transferred immediately using full-duplex relay technology, and transfer processing is performed without checking for the presence of interference from other transmitting station devices. Yes. For this reason, there is a possibility that the receiving station apparatus cannot receive normally due to the interference signal.

  The present invention performs carrier sense at the time of transfer while performing full-duplex relay, enables transfer processing according to the busy / idle status of the frequency channel, and avoids collisions due to interference signals at the receiving station device to improve throughput. It is an object of the present invention to provide a wireless relay system, a wireless relay method, and a wireless relay device that can be performed.

  A first invention is a wireless relay system in which a data frame transmitted from a transmitting station device to a receiving station device is received by a wireless relay device, reproduced, and immediately transferred by the frequency channel. The transmitting station apparatus includes means for dividing a data frame into a plurality of subframes and transmitting the data frame. The radio relay apparatus receives a data frame in units of subframes, and the frequency when a single subframe is normally received. Perform carrier sense on the channel, detect the remaining reception level after canceling the signal component of the received subframe from the entire received signal, and if the reception level is equal to or higher than a predetermined threshold, determine that the frequency channel is busy and Waits for frame transfer and repeats the process of receiving the next subframe. Comprising means for performing processing of transferring including the sub-frame that are waiting.

  In the wireless relay system of the first invention, when determining whether or not the subframe has been normally received, the wireless relay device proceeds to processing after carrier sense of the frequency channel if it has been normally received, In the case where normal reception is not possible, there is provided means for discarding a transfer-waiting subframe constituting one data frame and a subframe received thereafter.

  In the wireless relay system of the first invention, the wireless relay device does not perform carrier sense when the subframe of the next data frame is received after the transfer processing of the subframe constituting one data frame. In this configuration, the subframe transfer process is continued.

  A second invention is a wireless relay method in which a data frame transmitted from a transmitting station device to a receiving station device is received by a wireless relay device, regenerated, and immediately transferred through the frequency channel. The transmitting station apparatus performs processing to divide the data frame into a plurality of subframes and transmits the data frame, and the wireless relay apparatus receives the data frame in units of subframes and when one subframe is normally received. Performing carrier sense on the frequency channel, detecting the remaining reception level after canceling the signal component of the subframe received from the entire received signal by carrier sense, and frequency channel if the reception level is equal to or higher than a predetermined threshold Is busy, waits for subframe transfer, and receives the next subframe. Returns, and performing a process of transferring including the sub-frame the reception level is waiting until it is less than the threshold value.

  In the wireless relay method of the second invention, when determining whether or not the subframe has been normally received, the wireless relay device proceeds to the processing after the carrier sense of the frequency channel if it has been normally received, When it is not possible to receive normally, there is a step of discarding the transfer-waiting subframes constituting one data frame and the subframes received thereafter.

  In the wireless relay method of the second invention, the wireless relay device does not perform carrier sense when the subframe of the next data frame is received after the transfer processing of the subframe configuring one data frame. And continuing the sub-frame transfer process.

  According to a third aspect of the present invention, there is provided a wireless relay device that receives a data frame transmitted from a transmitting station device to a receiving station device through a predetermined frequency channel, reproduces the data frame, and immediately transfers the data frame through the frequency channel. A data frame transmitted from a transmitting station apparatus divided into a plurality of subframes is received, and when one subframe is normally received, carrier sense is performed on the frequency channel, and the subframe received from the entire received signal is received. Processing for detecting the remaining reception level with the signal component canceled and determining that the frequency channel is busy if the reception level is equal to or higher than a predetermined threshold, and waiting for the transfer of the subframe to receive the next subframe If the reception level is less than the threshold value, a means for performing a transfer process including the subframes waiting until then is provided.

  In the wireless relay device of the third invention, when determining whether or not the subframe has been normally received, if the subframe has been normally received, the process proceeds to the processing after the carrier sense of the frequency channel, and cannot be normally received Includes a means for discarding a transfer-waiting subframe constituting one data frame and a subframe received thereafter.

  In the present invention, a transmitting station device divides a data frame into a plurality of subframes and transmits the data frame, and a wireless relay device receives the subframe, performs carrier sense before starting the transfer of the first subframe, and is busy. If it is idle, it can be transferred sequentially including idle subframes. By canceling the signal component of the subframe from all received signals at the time of this carrier sense, only the interference component can be extracted, so that carrier sense is possible even with full-duplex relay. Thereby, it is possible to improve the throughput by avoiding the collision due to the interference signal in the receiving station apparatus.

It is a figure which shows the Example structure of the radio relay system of this invention. It is a figure which shows the reception state of the sub-frame at the time of carrier sense. It is a figure which shows the reception state of the sub-frame at the time of carrier sense. It is a figure which shows the process sequence of the radio relay apparatus of this invention. It is a figure which shows the structural example and subject of the conventional wireless relay system.

FIG. 1 shows an embodiment of the wireless relay system according to the present invention.
In FIG. 1, the wireless relay system of this embodiment is configured to transfer data from a transmitting station (base station) device 10 to a receiving station (terminal station) device 30 via a wireless relay device 20. The subframe division transmission unit 11 of the transmission station apparatus 10 divides the data frame into a plurality of subframes and transmits the data frames. At the end of each subframe, an FCS region used for determining whether or not the subframe is a normal subframe transmitted from the transmitting station apparatus 10 by performing error detection (for example, CRC check) is provided.

  The regenerative relay unit 21 of the radio relay apparatus 20 receives data frames in units of subframes, and normally receives the first subframe 1 transmitted from the transmission station apparatus 10 by, for example, error detection by CRC check (demodulation / decoding). ), If subframe 1 is normally received and the carrier sense described below is performed and the frequency channel is idle, subframe 1 and the subsequent subframes are sequentially transferred. If the frequency channel is busy, it waits for the transfer of subframe 1 and performs the same processing for the subsequent subframe 2 and subsequent data. When the frequency channel becomes idle, the data including the subframe that is on standby All subframes constituting the frame are sequentially transferred.

  On the other hand, when the state in which the subframe cannot be normally received continues and the subframe that has been normally received for the first time is not the first subframe 1 of the data frame, the subsequent subframes constituting the data frame are not transferred. In addition, if the subframe is normally received but the channel is busy and repeats waiting for transfer, if there is a subframe that cannot be received normally, the data frame including the subframe that is on standby is included. No subframe is transferred.

  A feature of the present invention is that, in addition to the above-described transfer processing in units of subframes, the carrier sense unit 22 uses for transmission / reception according to an instruction from the regenerative relay unit 21 before transferring the first subframe 1 that has been normally received. The carrier sense is performed in the frequency channel. The reception state of the subframe at this time is shown in FIG.

  FIG. 2 (1) shows a state where a subframe and an interference signal overlap at the time of carrier sense, and when both reception levels are equal, a CRC check error occurs and the subframe cannot be received. In this case, other subframes constituting the data frame are also discarded.

  FIGS. 2 (2) and 2 (3) show a state in which a subframe and an interference signal overlap at the time of carrier sense, but can be received as a subframe because the reception level of the interference signal is small. When the first subframe 1 transmitted from the transmitting station device 10 has been successfully received, the carrier sense unit 22 cancels the signal component of the subframe received from the entire received signal, and determines the remaining reception level as an interference component. Extract as It is determined whether or not the reception level of this interference component is equal to or higher than a predetermined threshold. As shown in FIG. 2 (2), if the reception level is equal to or higher than the predetermined threshold, it is determined that the frequency channel is busy. As shown in (2), if it is less than the threshold value, it is determined to be idle.

  The regenerative repeater 21 of the wireless relay device 20 receives subframe 1 normally, and when the carrier sense unit 22 determines that the frequency channel is idle, it also sequentially transfers subframe 1 and subframe 2 and subsequent frames. On the other hand, if the carrier sense unit 22 determines that the frequency channel is busy, the storage unit 23 is made to wait for the subframe 1. Next, the regenerative relay unit 21 determines whether or not the subframe 2 is normally received, and receives the subframe 2 normally, and when the carrier sense unit 22 determines that the frequency channel is idle, the storage unit 23, the subframe 1 stored in the frame 23 and the subframe 2 and subsequent frames are sequentially transmitted. This is shown in FIG. If the frequency channel is busy when subframe 2 is received, the same processing is repeated. However, when a missing subframe occurs during the repetition, the subsequent subframes that make up the data frame including the waiting subframe are not transferred as described above.

FIG. 4 shows a processing procedure example of the wireless relay device of the present invention.
In FIG. 4, the radio relay apparatus starts with no signal being received or being transferred (idle) (S1), and receives a subframe length signal (S2). A CRC check is performed on this signal, and it is confirmed whether or not the subframe from the transmitting station apparatus is normally received (S3). Here, when it is confirmed that the first subframe 1 has been normally received, carrier sense peculiar to the present invention is performed. That is, the signal component of the subframe received from the entire received signal is canceled and the remaining reception level is extracted as an interference component, and it is determined whether or not the reception level of this interference component is equal to or greater than a predetermined threshold (S4). Here, if the reception level of the interference component is less than the predetermined threshold, it is determined that the frequency channel is idle, and subframe 1 and all subframes constituting the data frame that arrives thereafter are sequentially transferred (S5). .

  On the other hand, if the reception level of the interference component is equal to or higher than the predetermined threshold, it is determined that the frequency channel is busy, and subframe 1 is stored in storage 23 by waiting for transfer (S6), and the process returns to step S2 to return to the next subframe. The reception process is continued. If it is confirmed that the subframe 2 has been normally received, it is similarly determined whether or not the reception level of the interference component is equal to or higher than a predetermined threshold (S3, S4). Here, if the reception level of the interference component is less than a predetermined threshold, it is determined that the frequency channel is idle, and as shown in FIG. 3, all the subframes constituting the data frame including the subframe 1 waiting for transfer are included. Are sequentially transferred (S5).

  When the transfer of all subframes constituting the data frame is completed in step S5, if the subframe of the next data frame has already been received, all the subframes constituting the data frame are sequentially transferred. Forward.

  In step S3, if the subframe from the transmitting station apparatus cannot be received normally, or if the first subframe received normally is not the first subframe 1, or if the subframe received normally is on standby due to channel busy If the next subframe cannot be normally received, the subframes that have been received / untransferred up to that point and all the subframes constituting the data frame to be received thereafter are discarded (S7).

DESCRIPTION OF SYMBOLS 10 Transmitting station apparatus 20 Radio relay apparatus 21 Regenerative relay part 22 Carrier sense part 23 Storage part 30 Receiving station apparatus 51,54 Transmitting station apparatus 52 Radio relay apparatus 53,55 Receiving station apparatus

Claims (8)

In a wireless relay system in which a data frame transmitted from a transmitting station device to a receiving station device is received by a wireless relay device, reproduced, and immediately transferred through the frequency channel.
The transmitting station apparatus comprises means for dividing the data frame into a plurality of subframes and transmitting the data frame,
The radio relay apparatus receives the data frame in units of subframes, performs carrier sense on the frequency channel when one subframe is successfully received, and receives the signal component of the subframe received from the entire received signal The process of detecting the remaining reception level that has been canceled, and determining that the frequency channel is busy if the reception level is equal to or greater than a predetermined threshold, waiting for the transfer of the subframe, and receiving the next subframe. Repeatedly, if the reception level is less than a threshold value, the wireless relay system includes means for performing a transfer process including a subframe that has been waiting until then. The wireless relay system according to claim 1,
When determining whether or not the subframe has been normally received, the wireless relay device proceeds to processing after carrier sense of the frequency channel if the subframe has been normally received. A wireless relay system comprising: means for discarding a subframe waiting for transfer and a subframe received thereafter, which constitute one data frame. The wireless relay system according to claim 1,
When the wireless relay apparatus receives a subframe of the next data frame after the transfer process of the subframe constituting one data frame, the radio relay apparatus continues without performing the carrier sense. A wireless relay system characterized in that the transfer process is continued. In a wireless relay method in which a data frame transmitted from a transmitting station device to a receiving station device is received by a wireless relay device, reproduced, and immediately transferred by the frequency channel.
The transmitting station apparatus performs processing of dividing the data frame into a plurality of subframes and transmitting the data frame,
The wireless relay device is
Receiving the data frame in units of subframes;
Performing carrier sense on the frequency channel when one subframe is successfully received;
Detecting a remaining reception level obtained by canceling a signal component of a subframe received from the entire reception signal by the carrier sense;
If the reception level is equal to or higher than a predetermined threshold, the frequency channel is determined to be busy, and the process of waiting for the transfer of the subframe and receiving the next subframe is repeated. And a step of performing a transfer process including a subframe that is waiting until then. The wireless relay method according to claim 4,
When determining whether or not the subframe has been normally received, the wireless relay device proceeds to processing after carrier sense of the frequency channel if the subframe has been normally received. A wireless relay method comprising: a step of discarding a subframe waiting for transfer and a subframe received thereafter, which constitute one data frame. The wireless relay method according to claim 4,
When the wireless relay apparatus receives a subframe of the next data frame after the transfer process of the subframe constituting one data frame, the radio relay apparatus continues without performing the carrier sense. A step of continuing the transfer process of the above. In a radio relay apparatus that receives and reproduces a data frame transmitted from a transmitting station apparatus to a receiving station apparatus on a predetermined frequency channel by a radio relay apparatus, and immediately transfers the data frame on the frequency channel.
The data frame transmitted from the transmitting station device divided into a plurality of subframes was received, and when one subframe was successfully received, carrier sense was performed on the frequency channel and received from the entire received signal The remaining reception level in which the signal component of the subframe is canceled is detected. If the reception level is equal to or higher than a predetermined threshold, the frequency channel is determined to be busy, waiting for transfer of the subframe, A radio relay apparatus comprising: means for repeating a process of performing reception, and performing a process of transferring including a subframe that has been waiting until then if the reception level is less than a threshold value. The wireless relay device according to claim 7,
When determining whether or not the subframe has been normally received, if the subframe is normally received, the process proceeds to the processing after the carrier sense of the frequency channel. If the subframe is not normally received, one data frame is formed. A wireless relay device comprising means for discarding a subframe waiting for transfer and a subframe received thereafter.

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