JP2010154285A - Relaying station and relaying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relaying station and a relaying method for alleviating delay in the relaying operation. <P>SOLUTION: The relaying station includes a means for receiving a first data having a plurality of first segments which are respectively given a first sequence number from a first radio communication apparatus for each first segment, a means for arranging the plurality of first segments received within a constant period in accordance with order of first sequence numbers and generating G pieces of groups by dividing the first segments among the segments to provide non-continuous first sequence numbers, a means for forming coupled data by coupling the first segment for each group and re-segmenting the coupled data into one or more second segments, a means for giving the continuous second sequence numbers starting from X+P (X is the second sequence number of the second segment at the last digit of the (M-1)th group and P is integer 3 or larger) of the first digit to the second segment included in the Mth group (M is integer equal to or larger than 2 and equal to or smaller than G), and a means for transmitting the second segment to the second radio communication apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a relay station and a relay method in a wireless communication system, for example, a reception and transmission method in a MAC (Media Access Control) layer of the relay station.

  For the next generation PHS (Personal Handy-phone System), physical layer and MAC layer standards are defined (Non-Patent Document 1).

  In the next-generation PHS standard, data higher than the MAC layer is divided into segments according to the MAC frame size mapped in the PHY payload. An appropriate MAC header is added to a MAC payload corresponding to the segment itself or a MAC payload including padding bits for size adjustment, and a MAC frame is generated. Further, a CRC code and a tail bit are added to the MAC frame to generate a PHY data unit, and this PHY data unit is mapped and transmitted on a radio resource divided by time and frequency.

  The MAC header includes some information necessary for reconstructing higher layer data by concatenating segments included in the MAC frame. In particular, the sequence number included in the MAC header is a consecutive number given in the order in which the transmission source device generated the MAC frame. In addition, the MAC header includes information on whether or not the upper layer data segment is included in the MAC frame, information on whether or not the segment is the top segment obtained by cutting out the upper layer data, and segment size information. . Based on this information and the order of the sequence numbers described above, segments can be extracted from the received MAC frame and concatenated to reconstruct upper layer data.

  In addition, when communication is performed between the base station and the terminal, a relay station is interposed between the base station and the terminal, and the relay station receives transmission data from the base station and relays it to the terminal. Or the utilization form that a relay station receives the transmission data from a terminal and relay-transmits to a base station is known (for example, nonpatent literature 1).

  Based on the next-generation PHS standard, when a relay station is interposed between a base station and a terminal and operated, the relay station is a terminal when viewed from the base station, and the relay station is the base station when viewed from the terminal. In the wireless communication between the base station and the relay station and between the relay station and the terminal, the following processing is usually performed in accordance with the procedures of the physical layer and the MAC layer.

  For example, it is assumed that the relay station receives data transmitted from the base station and relays the data to the terminal. In this case, assuming that the upper layer data is always relayed, the relay station looks at the MAC header of the received MAC frame. Reconstruct upper layer data based on information. Further, a segment is extracted from the reconstructed higher layer data according to the PHY payload size that can be used by the relay station for transmission, and a MAC header is added to the MAC payload including the segment to generate a MAC frame. Then, the above-described PHY data unit is generated from the MAC frame, this PHY data unit is mapped to a radio resource, and the relay station performs relay transmission.

  On the other hand, as another relay method, a method is also known in which relay transmission is performed in units of received MAC frames (Patent Document 1).

In this method, the relay station confirms the MAC header of the MAC frame received from the relay source device, and if higher layer data is included, the segment is extracted from the MAC payload. Depending on the MAC payload size available for transmission to the relay destination device by the relay station, if the segment can be transmitted as it is, the MAC frame is generated by adjusting the size with padding bits as necessary, Further, a PHY data unit is generated, mapped to a radio resource, and transmitted. If the size is too large, the segment is divided into an appropriate size to generate a plurality of MAC frames, and further a plurality of PHY data units are generated, mapped to a plurality of radio resources, and transmitted. In this method, relay transmission can be performed in units of MAC frames received by the relay station without performing reconstruction processing of higher layer data.
ARIB Standard STD-T95 “OFDMA / TDMA TDD Broadband Wireless Access System (Next Generation PHS) ARIB STANDARD”, 1.0 JP 2008-153778, paragraph 15, Fig. 10

  However, the method of relay transmission as it is in units of MAC frames received by the relay station as described above fills in the size difference between the data to be relayed and the radio resource that the relay station can use for relay transmission with padding bits, so the effective throughput is low. There is a problem that the transmission efficiency is poor.

  Therefore, considering transmission efficiency, the relay station must regenerate the transmission MAC frame after reconstructing higher layer data from the segments included in multiple received MAC frames instead of the received MAC frame unit as it is. Is usually considered.

  As described above, in the next-generation PHS standard, consecutive sequence numbers are always assigned in the order in which MAC frames are generated from segments cut out from higher layer data.

  Here, when data is transmitted from the base station to the terminal, if a relay station intervenes in the middle, as described above, the upper layer data is reconstructed once from the MAC frame received by the relay station, and then the relay A MAC frame is generated by re-cutting the segment into segments that are convenient for the station.

  However, the relay station may not always receive the received MAC frames in the order of the sequence numbers due to the occurrence of a CRC error, etc. It may be received in line.

  When reconstructing higher layer data from the received MAC frame, if the sequence number becomes discontinuous and some MAC frames are missing on the way, the missing MAC frame is usually The reconstruction of higher layer data is interrupted until it can be received by retransmission at a later time. As a result, the generation of the MAC frame relayed by the relay station is also delayed.

  Therefore, even if the MAC frame with the sequence number succeeding from the MAC frame missing in the middle is correctly received, and the radio resource for relay transmission by the relay station is secured at that time, Since the MAC frame for relay transmission is not ready, the resource cannot be used. As a result, there is a problem that the delay due to the relay transmission becomes larger because the relay transmission process is postponed.

  The present invention addresses these problems, and provides a relay station and a relay method that can reduce delay caused by relays.

The relay station as one aspect of the present invention,
A relay station that relays communication from the first wireless communication device to the second wireless communication device, and has first data having a plurality of first segments each assigned a first sequence number, Receiving means for receiving from the first wireless communication device every time;
A plurality of the first segments received within a predetermined time are arranged in the order of the first sequence numbers and divided between the segments where the first sequence numbers are discontinuous, so that G (G is an integer of 2 or more) Group generation means for generating a group;
Re-segmentation means for concatenating the first segments for each group to generate concatenated data and re-segmenting the concatenated data into one or more second segments;
For the second segment included in the Mth (M is an integer greater than or equal to 2 and smaller than G) th group, the top is X + P (X is the second sequence number of the second segment at the end of the M−1th group) , P is an integer of 3 or more) sequence number giving means for giving the second sequence numbers consecutive,
Transmitting means for transmitting the second segment to the second wireless communication device;
Is provided.

The relay method as one aspect of the present invention includes:
A relay method executed in a relay station that relays communication from a first wireless communication apparatus to a second wireless communication apparatus, wherein first data having a plurality of first segments each assigned a first sequence number Receiving a segment from the first wireless communication device for each first segment;
A plurality of the first segments received within a predetermined time are arranged in the order of the first sequence numbers and divided between the segments where the first sequence numbers are discontinuous, so that G (G is an integer of 2 or more) A group generation step for generating a group;
Re-segmenting the first segment for each group to generate concatenated data and re-segment the concatenated data into one or more second segments;
For the second segment included in the Mth (M is an integer greater than or equal to 2 and less than or equal to G) th group, the top is X + P (X is the second sequence number of the second segment at the end of the M−1th group) , P is an integer greater than or equal to 3) and the sequence number assigning step for assigning the second sequence numbers consecutively starts with,
Transmitting the second segment to the second wireless communication device;
Is provided.

  According to the present invention, delay due to relay can be reduced.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

(First embodiment)
FIG. 2 shows a usage form in which the base station performs wireless communication with the terminal via the relay station in the next-generation PHS.

  In this usage mode, in the downlink, the base station 201 transmits downlink data to the relay station 203 existing in the communication area 202, and the relay station 203 relays the data to the terminal 204. In the case of this downlink, the base station 201 corresponds to the first radio communication device, and the terminal 204 corresponds to the second radio communication device. On the other hand, in the uplink, the terminal 204 transmits uplink data to the relay station 203, and the relay station 203 relays the data to the base station 201. In the case of this uplink, the terminal 204 corresponds to the first radio communication device, and the base station 201 corresponds to the second radio communication device. In the wireless connection via the relay station 203 in this usage mode, the relay station 203 behaves like a terminal from a base station and like a base station from a terminal.

  The next generation PHS is a TDD (Time Division Duplex) system, and as shown in FIG. 3, a total of 8 slots including 4 uplink slots and 4 downlink slots are included in a 5 ms frame defined in the physical layer. Further, as shown in FIG. 4, a subchannel (SCH) in which the system band is divided into 900 kHz intervals is defined in the frequency axis direction, and the PHY data is defined in a section (radio resource) divided by the slot and the subchannel. Map units.

  When a relay station exists, in the downlink, wireless communication is performed by dividing the four downlink slots into two wireless connections between the base station and the relay station and between the relay station and the terminal. For example, as shown in FIG. 5, a method of using the first two slots (A) from the base station to the relay station and the second two slots (B) from the relay station to the terminal among the four downlink slots can be considered. In this example, the data received in the slot (A) from the base station is transmitted from the relay station to the terminal using the same slot (B) of the 5 ms frame, or considering the decoding delay of the received data, The data is relay-transmitted from the relay station to the terminal using the slot (B) of the subsequent 5 ms frame.

  In the following, a detailed description will be given in detail until the downlink data is transmitted from the base station to the relay station, and the relay station relays the data to the terminal. That is, the relay operation by the relay station when the base station is the first wireless communication apparatus and the terminal is the second wireless communication apparatus will be described. However, the present invention is not limited to the downlink, and an equivalent procedure can be applied to the uplink.

  As shown in FIG. 1, the base station divides the upper layer data from the MAC layer (hereinafter referred to as upper layer data) according to the size of the PHY data unit that can be used by the base station for transmission, thereby dividing the segment. Generate. Here, the size of the PHY data unit is set in advance by the base station according to the state of the transmission path, and is notified in advance by the control channel to the terminal side (the relay station that relays transmission to the terminal is Since it behaves like a base station when viewed from the terminal, the PHY data unit size used when transmitting to the terminal is the one set by the relay station itself according to the status of the transmission path. In advance).

  Further, the base station generates a MAC frame by adding a MAC header including a sequence number or the like to the MAC payload including the generated segment. The sequence number assigned by the base station corresponds to the first sequence number of the present invention (note that the sequence number assigned by the relay station corresponds to the second sequence number as will be described later). A CRC check bit and a tail bit for error detection are added to the generated plurality of MAC frames to generate a PHY data unit. The PHY data unit is allocated to a part of the temporarily reserved radio resource (section divided by the slot and the subchannel shown in FIG. 4) to perform radio transmission. Each MAC frame (or each PHY data unit) generated based on the upper layer data corresponds to a first segment to which the first sequence number of the present invention is assigned. Forming the first data of the invention.

Also, three formats are defined in the MAC header including the sequence number and the like as shown in FIG. Each format contains several elements. The description of each element is as follows.
-B: Indicates whether it is the first segment when the upper layer data is divided into segments (1 bit, “1” for the first).
CD: Indicates the type of data contained in the MAC payload (2 bits, upper layer data if “11”).
MD: Indicates whether two or more upper layer data are included in the MAC payload.
-F: Indicates whether the MAC payload length is represented by L (1 bit, if it is “0”, it is represented by L).
-QI: Indicates the session ID.
• N: Indicates the sequence number (8 bits) (sequence numbers are always consecutive).
• L: Indicates the MAC payload size in bytes (8 or 16bit).
IX: Indicates the number of bytes transmitted before this MAC frame (8 or 16 bits) when upper layer data is divided into segments and transmitted.

  Here, the sequence number is information for rearranging the upper layer data divided into segments and reconstructing the sequence number, and the sequence number is given in the order in which the MAC frames to be transmitted by the transmission device are generated. However, since the sequence number is represented by 8 bits, it is a number from 0 to 255. When the maximum value 255 is reached, the next sequence number returns to 0.

  FIG. 7 is a diagram for explaining an example of processing until the base station divides upper layer data into a plurality of segments, adds a MAC header to a MAC payload including each segment, and generates a plurality of transmission MAC frames. is there.

  The head segment of the upper layer data n is distinguished by the element B of the MAC header. Therefore, the format 1 is applied to the MAC frame 1 including the head segment, and the MAC header 1 in which the element B is set to 1 is added to the MAC payload including the head segment. At this time, the element L of the MAC header 1 has a value larger than the MAC payload length, and indicates the size of the entire upper layer data before being divided into segments. The sequence number of the MAC header 1 is k. This is because the sequence number of the last segment of the previous upper layer data n-1 is k-1, and it is necessary to be an integer value continuous to k-1.

  Subsequently, MAC headers 2, 3, 4,... 9 are respectively added to the MAC payload including the intermediate segment to generate MAC frames 2-9. At this time, the elements N of the MAC headers 2 to 9 are always consecutive integer sequence numbers k + 1 to k + 8.

Since the last segment is 10 bytes in size and the MAC payload size is 40 bytes, the MAC frame 10 is generated by adding the MAC header 10 after adjusting the size difference with padding bits. In the MAC header 10 added to the MAC payload including the last segment, the amount of padding can be seen by looking at the element L. Further, the sequence number N of the MAC header 10 is an integer k + 9 that is continuous with the sequence number k + 8 of the previous segment (therefore, the sequence number of the first segment of the subsequent higher layer data n + 1 is k + 10).
As described above, the MAC frame generated from each segment cut out from one upper layer data is appended with CRC and TAIL as a PHY data unit, and each PHY data unit is mapped to a radio resource and transmitted. Is done. That is, data (first data) having a plurality of PHY data units (a plurality of first segments each assigned with a first sequence number) generated based on upper layer data is obtained for each PHY data unit (first Send every segment).

  Here, it is assumed that each MAC frame is transmitted within one frame of a 5 ms frame as shown in FIG. 8 or transmitted across two or more 5 ms frames as shown in FIG. In the following description, a case as shown in FIG. 9 is assumed.

  Next, a process until the relay station receives the MAC frame transmitted from the base station and the relay station transmits the upper layer data extracted from the MAC frame to the terminal will be described with reference to FIG.

  The relay station receives the transmission data from the base station included in one frame (fixed time) of 5 ms width by the receiving means, and extracts the MAC frame that can be correctly received by the CRC check from the received PHY data unit. Further, it is determined whether to relay by looking at the MAC header information included in the MAC frame. Here, considering the case where the upper layer data is necessarily relayed, it can be determined whether or not the upper layer data is included by the element CD of the MAC header.

  Next, the MAC header element N included in the relayed MAC frame, that is, the sequence number (first sequence number) is seen, and the relayed MAC frames are arranged in the order of the sequence number. Further, MAC frames having consecutive sequence numbers are selected and grouped and numbered in order. In other words, if there is a MAC frame with a discontinuous sequence number in the middle, the group will be divided before and after. In this way, the base station arranges MAC frames received within one frame (fixed time) in order of sequence number and divides the MAC frames in which the sequence numbers become discontinuous into G (G is an integer of 2 or more). Generate a group of This processing is performed by group generation means provided in the base station, and the group generation means is included in the PHY / MAC frame processing unit 2707 of the base station (see FIG. 27). However, even if the sequence numbers are consecutive, if the MAC header element B is “1”, that is, if there is a MAC frame including the top segment of the upper layer data, the group is divided before and after that.

  The example of FIG. 10 shows a case where all the sequence numbers of MAC frames that can be correctly received by the CRC check are continuous and there is no discontinuous portion. In this case, MAC frames are arranged in order of sequence numbers in STEP 10-1 of FIG. 10, and MAC frames having consecutive sequence numbers are grouped in STEP 10-2. There is only one group 1 with consecutive sequence numbers. In STEP 10-3, segments are extracted from the MAC frame, and in STEP 10-4, the segments are concatenated based on the MAC header to generate partial concatenated data (also simply referred to as concatenated data) of higher layer data. Generation of concatenated data by concatenating segments is performed as one function by re-segmentation means provided in the base station. As will be described later, the re-segmentation means also performs a process of re-segmenting the concatenated data into one or more segments (second segments). The re-segmentation means is included in the PHY / MAC frame processing unit (see FIG. 27) of the base station.

  Here, the relay station holds a received MAC frame management table as shown in FIG. 11, and manages the header information of the MAC frame received by this table.

  In the table of FIG. 11, “MAC Seq Num” indicates the sequence number of the MAC frame (value of element N of the MAC header), and “completion flag” indicates whether the relay transmission processing of the received data is completed (“1” "Complete", "0" not complete), "Resend flag" indicates whether or not the received MAC frame has been retransmitted ("1" means retransmission, "0" means no retransmission). Also, the table holds the group number of each MAC frame so that different groups can be distinguished from each other.

  In the header of the MAC frame including the top segment of the upper layer data, the size (L) of the entire upper layer data is described. The L value of the header of the MAC frame including the head segment is necessary for specifying the last segment of the upper layer data when the segments are connected.

  In the example of FIG. 11, the segment of sequence number 12 is the first segment (the value of B is 1), and the segments are connected in order from this segment. Since the IX value indicates the total size of the segments that have been transmitted so far, the sum of the IX value corresponding to a certain segment and the size of the certain segment (= MAC Payload Size) is the IX value corresponding to the next segment. It is sufficient to check in order and connect them. At this time, if the sum of the IX value corresponding to a certain segment and the segment size matches the overall size of the upper layer data (L value described in the header of the first segment), that segment becomes the last segment. Therefore, the concatenation process ends there. Here, since the segment 19 is the last segment, the concatenation process ends here.

  Next, in order to generate a MAC frame for relay transmission, the relay station uses the re-segmentation means to convert the partial concatenated data concatenated by the received segments of each group according to the MAC payload size that can be used by the relay station for transmission. Segment to generate one or more segments (second segment).

  In the example shown in FIG. 10, the number of groups is one, and the generated partial data of the upper layer data is only one. Therefore, according to the MAC payload size that can be transmitted by the relay station as shown in FIG. A segment is cut out, an appropriate MAC header is added, and a MAC frame is generated and transmitted.

  Here, the sequence number set in the transmission MAC frame (corresponding to the second sequence number of the present invention) is determined by the relay station according to its transmission state, and the MAC frame transmitted from the base station to the relay station. Note that this is independent of the sequence number set to (corresponding to the first sequence number of the present invention). The determination and assignment of the sequence number (second sequence number) is performed by sequence number assigning means provided in the base station. The sequence number assigning means is included in the header information generating unit (see FIG. 27) of the base station as will be described later.

  As shown in FIG. 11, the first segment of group number 1 is the top segment of the higher layer data. In this example, when a segment is cut out from the partially connected data of group 1, the first segment has a sequence number 34 and the MAC frame format is 1, as shown in FIG.

  In the subsequent MAC frame, the sequence number is incremented in order, the segment is cut out in accordance with the MAC payload size, and the MAC header value is determined. The MAC frame format should be 2. The last segment cut out may not fit the MAC payload size, so use MAC frame format 3 to specify the segment size with the MAC header element L and process the remainder with padding bits. Good. Note that format 2 may be used when it is not necessary to add padding bits to the last segment.

  Here, the relay station has the transmission MAC frame management table of FIG. 13, and manages the header information of the transmission MAC frame generated as described above using this table.

  Next, consider a case where there is a portion where the sequence numbers are discontinuous.

  FIG. 14 shows a case where a relay station receives MAC frames when there is a part where the sequence numbers are discontinuous and the number of groups is 2 (G = 2), and transmits upper layer data extracted from them to the terminal It is a figure explaining the example of the process until it does.

  In this case, the base station uses the group generation means to arrange the MAC frames in which the sequence numbers are consecutive in STEP 14-2 by arranging them in the order of the sequence numbers in STEP 14-1 in FIG. Two groups, group 1 and group 2, are generated. Next, the base station extracts the segment from the MAC frame in STEP 14-3 by the re-segmentation means, concatenates the segments based on the MAC header in STEP 14-4, and partially concatenates the upper layer data in each group. Generate data. Since there are two groups, two partially linked data are also generated.

  The header information of the received MAC frame is managed by the received MAC frame management table as described above, and the table of this example is as shown in FIG. In the table of FIG. 15, blank lines corresponding to missing sequence numbers are inserted between group 1 and group 2, but this is for ease of viewing and there is no problem even if they are packed.

  Next, the relay station uses the above re-segmentation means to generate the MAC frame to be relayed according to the MAC payload size that can be used by the relay station to transmit the partial concatenated data concatenated by the received segments of each group. To generate one or more segments (second segments) for each group.

  First, the process is the same as in the case of FIG. 10 until a segment is cut out from the partially connected data generated from the first group 1 and a MAC frame is generated. Specifically, as shown in FIG. 16, a segment is cut out from the partially concatenated data of group 1 according to the MAC payload size that can be transmitted by the relay station, an appropriate MAC header is added, and a MAC frame is generated and transmitted. Further, for the MAC frame that has undergone relay transmission processing, the contents of the MAC header and the like are held in the transmission MAC frame management table as described above, and the current table is as shown in FIG.

  Next, the process enters a process of generating a MAC frame by extracting a segment from the partially concatenated data of group 2 in FIG. 16. At this time, the MAC frame that should be arranged between group 1 and group 2 cannot be received. The sequence number cannot be determined so as to be “continuous” in order from the sequence number of the last MAC frame generated from the partially concatenated data of 1. In the conventional method, as described above, it waits until the retransmission is completed and starts generating the MAC frame for relay transmission when the necessary data is available. Is bad.

  Therefore, the sequence number that has been advanced by some amount from the sequence number of the last MAC frame generated from the partially connected data of group 1 is the MAC frame generated from the first segment extracted from the partially connected data of group 2 It shall be a sequence number. That is, some sequence numbers are reserved and unused. Here, the amount by which the sequence number is advanced is represented by P, and P is an integer of 3 or more. This is in order to consider a case where a break in higher layer data is included in a MAC frame portion that has not been received yet. If there is a break in the upper layer data, it is necessary to distinguish the sequence numbers of the MAC frames before and after the different ones, so that at least two unused numbers are secured.

  As described above, when the sequence number is advanced, the sequence numbering method does not become continuous between the group 1 and the group 2, but this is because the data that has not been received yet (that is, at the end of the group 1). A segment having a sequence number (first sequence number) between the sequence number of the segment located (first sequence number) and the sequence number of the segment located at the beginning of group 2 (first sequence number) (MAC frame or When the PHY data unit)) is received at a later time, it is reserved in advance as a number used to send the data. Later, when unreceived data that has been missed in the middle is received in time, a problem arises in the segment concatenation order on the terminal side by generating and transmitting a MAC frame so that the reserved sequence number is always used up. Do not leave. In this way, when the terminal finally receives the MAC frames and arranges them in the order of the sequence numbers, the numbers do not become discontinuous, and the upper layer data can be reconstructed without any problem.

  Here, as described above, a method for determining a specific amount P to advance the sequence number in advance is required, but in this embodiment, the amount by which the sequence number of the received MAC frame is discontinuous is determined. Use. Assuming that there is little difference in the usage of radio resources available between the relay source device and the relay station and between the relay station and the relay destination device, when the relay station receives the MAC frame, the sequence If the amount of deviation of the part where the number is discontinuous is matched, the reservation amount of the sequence number can be determined with a simple process.

  For example, in the example of FIG. 14, with reference to the table of FIG. 15, it can be seen that the amount of sequence number deviation at the time of reception is 4 (= 18-14). Therefore, since the sequence number of the last transmission MAC frame generated from the partially connected data of group 1 in FIG. 17 is 35, the first transmission MAC when the relay station transmits the segment of the partially connected data of group 2 The sequence number assigned to the frame starts from 39 which is increased by four. Specifically, as shown in FIG. 18, a transmission MAC frame is generated by adding a MAC header in which a sequence number 39 is set to the first segment cut out from the partially connected data of group 2. A MAC header in which the subsequent sequence number 40 is set is added to the second segment to generate a transmission MAC frame.

  In general, sequence numbers may be assigned to segments included in the Mth group (M is an integer of 2 to G). That is, for the segment (second segment) included in the Mth group, the head is X + P (X is the sequence number (second sequence number) of the last segment (second segment) of the M−1th group, A consecutive sequence number (second sequence number) starting with P is an integer of 3 or more is assigned.

  As described above, when relay transmission is completed after a sequence number is obtained, the contents of FIG. 17 are updated as shown in FIG. By looking at FIG. 19, it can be confirmed that there is an unused sequence number. When a MAC frame that has not been received with sequence numbers 15, 16, and 17 can be received later, when the relay station transmits partial concatenated data generated from the segments included therein, the sequence number is The MAC frame must be generated and transmitted so that 36, 37, and 38 are always used up.

  Next, a method of generating and sending a transmission MAC frame using all unused sequence numbers when a MAC frame that has not been received in the middle can be correctly received at a later time will be described.

  FIG. 20 shows a case where a MAC frame that has not been received in the middle can be received correctly at a later time. First, in STEP 20-1, the MAC frames are arranged in the order of sequence numbers. Next, it is known that there are three sequence numbers of MAC frames that are grouped in consecutive parts of the sequence numbers and that have not been received, that is, from FIGS. 15 to 15, 16, and 17. The frame is extracted (STEP 20-2). Further, segments are extracted from the extracted MAC frame (STEP 20-3), and these segments are concatenated to generate partial concatenated data (second concatenated data) of higher layer data (STEP 20-4). Also, by including the MAC frame information received here in the table, the state of the table is updated from FIG. 19 to FIG.

  Here, in FIG. 21, the group numbers are 1 → 3 → 2 from the top of the table row and are not in ascending order, so the group numbers are changed to be in ascending order from the top as shown in FIG. Further, in order to correspond to this, also in the table of FIG. 19, the corresponding group number portion is changed as shown in FIG. In this example, group number 2 is changed to number 3. This operation is necessary for performing processing according to the processing flow described later.

  Next, as shown in FIG. 24, the partial concatenated data (second concatenated data) is cut into three segments in accordance with the size that can be transmitted by the relay station. In general, using the above-described sequence number deviation amount P (P = 4 in this example), the partial concatenated data (second concatenated data) is cut into P−1 segments. The last segment may be adjusted by inserting padding bits if there is a size difference from the MAC payload.

  Further, a MAC header is added so that the three unused sequence numbers 36, 37, and 38 are used up, and a transmission MAC frame is generated to perform relay transmission. Generally, X + 1 to X + P-1 (where X is the sequence number of the last segment of the (M-1) th group as described above (second sequence number)) Are assigned consecutive sequence numbers (second sequence numbers). As a result, all unused sequence numbers are used up. When the relay transmission is completed, the transmission MAC frame table of FIG. 23 is updated as shown in FIG.

  FIG. 26 is a flowchart showing a processing flow until the relay station in this embodiment receives a MAC frame and relays it.

  First, in step 26-1, a MAC frame that has been correctly received by the CRC check within a 5 ms frame (fixed time) is specified, and the process proceeds to step 26-2.

  In step 26-2, the MAC header of the MAC frame that has been correctly received is read to group the MAC frames, and the received MAC frame management table is updated. At this time, the group numbers in the received MAC frame management table are changed in ascending order from the top. Similarly, the transmission MAC frame management table is changed so that the group numbers are in ascending order from the top. Proceed to step 26-3.

  In step 26-3, segment concatenation is performed for the group whose completion flag is “0” in the received MAC frame management table, and the process proceeds to step 26-4.

  In step 26-4, the smallest group number K having the completion flag “0” is selected from the received MAC frame management table, and the process proceeds to step 26-5.

  In step 26-5, it is confirmed whether there is unreceived data linked between the data of the groups K-1 and K.

  In step 26-6, when there is unreceived data connected between the data of groups K-1 and K (NO in step 26-5), it is confirmed whether the data of group K is retransmission data. If it is retransmission data (NO in step 26-6), the process returns to step 26-1. In this case, retransmitted data having consecutive sequence numbers is made to wait until reception of all data is completed.

  In step 26-8, if the data of group K is not retransmission data (YES in step 26-6), the partially concatenated data generated from group K is re-segmented, and the sequence number of the first segment is sequentially set as X + P. Generate a MAC frame and relay it. X is a transmission MAC frame generated from the group K-1 and has the largest sequence number. P is an integer greater than or equal to 3, and in this example, the value of P is adjusted to the amount of deviation in which the sequence numbers are discontinuous between groups of received MAC frames. When the deviation amount is 2, the value of P is the lowest value of 3, and when the deviation amount is 3 or more, the value of P is set to the same value as the deviation amount, for example. Furthermore, the transmission MAC frame management table is updated based on the transmitted MAC frame information. Proceed to step 26-12.

  In step 26-7, when there is no unreceived data linked between the data of groups K-1 and K (YES in step 26-5), it is confirmed whether the data of group K is retransmission data.

  In step 26-9, if the data of group K is retransmission data (YES in step 26-7), the transmission MAC frame management table is checked, and the reserved sequence number that is not used is found. Check if it exists.

  If an unused sequence number is reserved in step 26-10 (YES in step 26-9), a MAC frame is generated and relayed so that all the numbers are used up. Furthermore, the transmission MAC frame management table is updated based on the transmitted MAC frame information. Proceed to step 26-12.

  In step 26-11, if the data of group K is not retransmission data (NO in step 26-7) or if an unused sequence number is not reserved (NO in step 26-9), partial concatenated data of group K Are segmented, and a MAC frame is generated from each segment and relayed. As a rule, the sequence number is set to a sequential value with the sequence number of the first segment as X + 1 as a rule. Furthermore, the transmission MAC frame management table is updated based on the transmitted MAC frame information. Proceed to step 26-12.

  In step 26-12, the completion flag of group K in the received MAC frame management table is changed to “1”, and the flow proceeds to step 26-13.

  In step 26-13, it is confirmed whether there is a group whose completion flag is “0” after group K. If not, the process ends. If there is, the process returns to Step 26-4.

  FIG. 27 is a block diagram illustrating an example of a relay station configuration.

  A signal from the base station is received by the antenna 2702, and the received signal is down-converted to a baseband signal by the RF processing unit 2703.

  The baseband reception digital processing unit 2704 acquires digital reception data by performing demodulation processing of the baseband signal, and the acquired reception data is sent to the communication control unit 2706 that performs frame processing and protocol processing in the PHY / MAC layer. send. The RF processing unit 27 and the baseband reception digital processing unit 2704 correspond to the receiving means of the present invention. An antenna 2702 may be included in the receiving means.

  The PHY / MAC frame processing unit 2707 of the communication control unit 2706 extracts the PHY data unit from the received data, performs a CRC check on the portion from which the TAIL bit has been removed, and receives the MAC for which no error was detected by the CRC check. Take out the frame. The extracted received MAC frame is temporarily stored in the data buffer 2708. This data buffer 2708 is used for holding partial concatenated data obtained by concatenating segments extracted from the MAC frame, and also for temporarily holding higher layer data that has been reconstructed after concatenation.

  The extracted received MAC frame is sent to the header information extracting unit 2711 to extract the MAC header, and the MAC header information is stored in the received MAC frame management table 2709.

  The PHY / MAC frame processing unit 2707 extracts a segment included in the MAC payload of the received MAC frame, and divides G (G is an integer of 2 or more) groups by dividing the segment into segments with discontinuous sequence numbers. Perform the processing to generate (group generating means processing), the process of connecting segments for each group to generate partially connected data (concatenated data generating processing by one function of re-segmentation means), etc. The upper layer data that has been configured and reconfigured is temporarily held in the data buffer 2708 in the communication control unit 2706. The partially concatenated data generated by the PHY / MAC frame processing unit 2707 is also temporarily stored in the data buffer 2708.

  In addition, the PHY / MAC frame processing unit 2707 also performs re-segmentation of the upper layer data temporarily stored in the data buffer 2708, partial concatenated data, and MAC frame generation processing. In particular, the PHY / MAC frame processing unit 2707 performs re-segmentation processing (re-segmentation processing by another function of the re-segmentation means) of the partially concatenated data concatenated in the relay processing. The header of the transmission MAC frame is generated using the header information generation unit 2712. Information on the MAC header of the transmission MAC frame is stored in the transmission MAC frame management table 2710.

  The header information generation unit (sequence number assigning means) 2712 has a sequence number advance amount determination unit 2713, and using this sequence number advance amount determination unit 2713, the processing of STEP 26-8 in the processing flow of FIG. Process to advance the number. In this process, from the received MAC frame management table 2709, the amount by which the sequence number is discontinuous between groups of received MAC frames is determined as the amount P to advance the sequence number. The header information generation unit (sequence number assigning means) 2712 is based on the transmission MAC frame management table 2710, and the sequence of the last segment by re-segmentation of the partial concatenated data generated from the group K-1 by this amount of the sequence number. From the value advanced from the number, it allocates to the segment by the re-segmentation of the partial connection data generated from the group K. When the sequence number is determined in this way and the MAC header is determined by the header information generation unit 2712, the MAC header is sent to the PHY / MAC frame processing unit 2707, and the PHY / MAC frame processing unit 2707 determines the transmission MAC frame. Generated.

  After generating the transmission MAC frame, the PHY / MAC frame processing unit 2707 sends the transmission MAC frame to the baseband transmission digital processing unit 2705, and the baseband transmission digital processing unit 2705 converts it into a baseband signal. The baseband signal is up-converted by the RF processing unit 2703 and wirelessly transmitted via the antenna 2702, whereby relay transmission is performed.

  The data is sent to the baseband transmission digital processing unit, up-converted by the RF processing unit 2703, wirelessly transmitted, and relay transmission is performed.

  In this embodiment, an example in which relay processing is performed in units of one hour frame is shown, but the present invention is not limited to this, and relay processing is performed in units of two or more time frames (predetermined constant time). Is also possible.

  In this embodiment, the MAC frame received by the relay station is grouped and concatenated, and re-segmented, so that radio resources used for communication with the terminal that is the relay transmitting partner (here, radio resources are (For example, frequency band, communication time, etc.) can be used in consideration of actual communication path conditions. That is, it is possible to optimally use radio resources. When it is not necessary to consider such optimization of radio resources, concatenation of MAC frames and re-segmentation are not necessary. The relay station newly adds a second sequence number to the segment included in the received MAC frame, and further includes a MAC header element that matches the connection status of the wireless circuit between the relay station and the relay destination communication device. A MAC frame may be generated by adding a MAC header and transmitted to the terminal.

  As described above, according to the present embodiment, even if a part is not received and missing, it is possible to start the transmission process of the next transmittable MAC frame first without waiting for the completion of the retransmission. In this way, relay transmission is performed first when there is data that can be transmitted, so that relay processing can be reduced compared to the method of relay transmission after waiting for completion of retransmission. It becomes possible to reduce the delay caused by the above.

(Second Embodiment)
In the first embodiment, the specific amount that the sequence number is advanced in advance is matched with the shift amount of the portion where the sequence number is discontinuous when the relay station receives the MAC frame. On the other hand, in this embodiment, the amount by which the sequence number is advanced is estimated as follows.

  In this embodiment, the data size is estimated using the IX value of the MAC header element. The IX value indicates the total size of the segments transmitted before the MAC frame including the IX value. The IX value corresponds to the total size information of the present invention. Therefore, for example, in the case of FIG. 15, since the IX value at sequence number 14 is 90 and the segment size of sequence number 14 is 20, the sum is 110, and this size has already been received. Next, since the IX value at sequence number 18 is 250, the total data size V that has not been received in the middle can be estimated by calculation of 250−110 = 140. Thus, the sum of the segments having the sequence numbers between the sequence number 14 of the last segment of group 1 (M-1th group) and the sequence number 18 of the first segment of group 2 (Mth group) Estimate size V. However, since the value estimated here may include not only net data but also padding data, the size of data retransmitted later from the base station may be smaller than the value estimated here.

  Next, the average size W of the MAC payload that the relay station can use for relay transmission at that time is obtained. In the case of FIG. 15, the MAC payload size of each MAC frame having a completion flag of 0 received within a 5 ms frame is known from the table, and can be calculated by obtaining the average value. In FIG. 15, the sum up to the MAC payload size 30 of the sequence number 19 is obtained by excluding the part not received midway from the MAC payload size 60 of the sequence number 12, and the average value may be obtained. If there are other usable MAC payloads other than those shown in FIG. 15, the average size is calculated including these other MAC payloads.

  Furthermore, when the amount P (integer) for advancing the sequence number is used, the value of the number of unused sequence numbers “P−1” is determined to be the minimum integer equal to or greater than V / W. That is, the value of “P” is determined to be (the minimum integer equal to or greater than V / W) +1. However, when V / W or more and the minimum integer is 2 or less, the value of P is set to the minimum value of 3.

(Third embodiment)
In the present embodiment, the amount by which the sequence number is advanced is estimated by a method different from the first and second embodiments.

  First, in the present embodiment, as in the second embodiment, the data size V that has been missed and is not received is estimated. The estimation method is the same as in the second embodiment.

  Furthermore, the size of the MAC payload that can be used when the relay station assumes relay transmission at that time, the size V is examined, the number of MAC payloads Z required to send data of size V is calculated, and the sequence number is Advancing amount P is determined to be Z + 1. The number of MAC payloads that the relay station can use for relay transmission and their respective sizes are notified in advance from the base station. In the example of FIG. 15, for example, MAC payloads of MAC frames with sequence numbers 18 and 19 and other available MAC payloads are used as available MAC payloads. Therefore, the number of segments Z generated when re-segmenting the total size V of the unreceived data in the middle with the available MAC payload notified in advance is necessary for transmitting data of size V Is the number of MAC payloads. Therefore, this number Z + 1 may be set as the sequence number advance amount P. However, when this value is 2 or less, the value of P is set to the minimum value of 3.

(Fourth embodiment)
In the present embodiment, the amount by which the sequence number is advanced is estimated by a method different from the first to third embodiments.

  First, in the present embodiment, as in the second embodiment, the data size V that has been missed and is not received is estimated. The estimation method is the same as in the second embodiment.

  Furthermore, it is assumed that the MAC payload size when transmitting at the minimum MCS (Modulation and Channel coding Scheme) defined in the standard, that is, at the minimum transmission rate, is H. The size that can be transmitted at the minimum MCS (minimum transmission rate) is known information defined in the standard. When the sequence number is advancing amount P, it is determined that the number of unused sequence numbers “P−1” is a minimum integer equal to or greater than V / H. That is, the value of “P” is determined to be (the minimum integer equal to or greater than V / H) +1. However, when V / H or more and the minimum integer is 2 or less, the value of P is set to the minimum value of 3.

(Fifth embodiment)
In the first embodiment, in FIG. 24, since the unused sequence numbers 36, 37, and 38 can be used up, they can be divided into three segments, but the number of sequence numbers that must be used up is the same. The number of segments cannot always be generated.

  Only a small MAC payload size that can be used for relay transmission by the relay station can be secured, and if segments are segmented from partially concatenated data, the number of segments may exceed the number of sequence numbers that must be used up. For example, in FIG. 28, four segments are generated for the number of sequence numbers that must be used up.

  In such a case, the same sequence number 38 may be assigned to the latter two segments as shown in FIG. In general, consecutive sequence numbers from X + 1 to X + P-2 are assigned to the first to P-2th segments, and a sequence number of X + P + 1 is commonly assigned to all the P-1 and subsequent segments.

  Here, in principle, sequence numbers are assigned consecutive numbers without discontinuity, but the next-generation PHS standard stipulates that MAC frames having the same sequence number may exist. In this procedure, even when the number of segments is larger than the number of sequence numbers that must be used up by using this rule at the time of relay transmission, “sequence numbers should be assigned consecutive numbers without discontinuity”. The principle can be observed. In this case, the actual order of MAC frames with the same sequence number can be specified by referring to the value of IX in the MAC header.

(Sixth embodiment)
In this embodiment, in order to use up unused sequence numbers 36, 37, and 38, it is divided into three segments almost equally, and a MAC payload that can contain the size of the segment is selected. . As shown in FIG. 29, the 140-byte partially concatenated data is substantially equally divided into three segments, and a MAC payload that can include each segment is selected. In this case, since 10 bytes are divided as a unit, it is almost equally divided into three segments of 50 bytes, 50 bytes, and 40 bytes. The size difference between the segment and the MAC payload may be padded as necessary. When the segment size is larger than the MAC payload size, for example, excess data at the end of the segment may be cut out and assigned to another MAC payload.

  As described above, the number of segments equal to the number of sequence numbers that need to be used up first is divided first, and after that, only the size adjustment needs to be taken into consideration, so the processing can be reduced.

(Seventh embodiment)
In the sixth embodiment, in FIG. 29, in order to use up unused sequence numbers 36, 37, and 38, it is almost equally divided into three segments. This is preferable in terms of reducing the delay.

  For example, as shown in FIG. 30, it is assumed that the MAC payload size that can be used when the relay station performs relay transmission can be large, and that only two segments can be generated by cutting out the partial concatenated data from the front. That is, it is assumed that only R segments less than P-1 can be generated using the deviation P. In this case, all of the data is sent in the MAC frames of the two previous sequence numbers 36 and 37, and dummy data may be inserted in the subsequent unnecessary portion of the sequence number 38. That is, sequence numbers X + 1 to X + R are assigned to the R segments, and the remaining sequence numbers X + R + 1 to X + P-1 may be assigned to dummy data. In this case, the MAC header can be used only including dummy sequence numbers because the data size is 0, that is, the element L is 0, so that only dummy data can be sent.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

Drawing for explaining from upper layer data to MAC frame generation in the next generation PHS standard. The figure for demonstrating the utilization form in which a base station performs radio | wireless communication with a terminal via a relay station in the next generation PHS standard. The figure for demonstrating the relationship between a 5ms frame and a slot in a physical layer. The figure for demonstrating the relationship between the slot of a 5 ms frame, and a subchannel. The figure for demonstrating an example which uses a downlink slot selectively between a base station and a relay station, and between a relay station and a terminal in a downlink. The figure for demonstrating the kind of MAC frame format of next generation PHS. The figure for demonstrating until upper layer data is divided | segmented into a segment and a MAC frame is produced | generated. The figure for demonstrating an example in which the produced | generated MAC frame is transmitted in a 5 ms frame area. The figure for demonstrating an example in which the produced | generated MAC frame is transmitted over several 5ms frame area. A diagram for explaining an example from when a relay station receives a MAC frame transmitted by a relay source device and reconstructs partially linked data of upper layer data from segments included in the MAC frame (an unreceived MAC frame in the middle) If not). The figure which shows the content of the reception MAC frame management table which a relay station hold | maintains. The figure for demonstrating until it produces | generates a MAC frame according to the MAC payload size which a relay station can utilize by relay transmission from the produced | generated partial connection data (when there is only one group). The figure which shows the content of the transmission MAC frame management table which a relay station hold | maintains. A diagram for explaining an example from when a relay station receives a MAC frame transmitted by a relay source device and reconstructs partially linked data of upper layer data from segments included in the MAC frame (an unreceived MAC frame in the middle) If there is). The figure which shows the content of the reception MAC frame management table which a relay station hold | maintains. The figure for demonstrating until it produces | generates a MAC frame according to the MAC payload size which can be utilized by relay transmission from the partial connection data which the relay station produced | generated (when there exist multiple groups). The figure which shows the content of the transmission MAC frame management table which a relay station hold | maintains. The figure for demonstrating until it produces | generates the MAC frame which relays the partial connection data produced | generated from the segment of the group 2 into a segment according to the MAC payload size which a relay station can utilize by relay transmission. The figure which shows the content of the reception MAC frame management table which a relay station hold | maintains. The figure for demonstrating the segment connection of the part, when a relay station receives the MAC frame with the sequence number which was missing on the way later. The figure which shows the content of the reception MAC frame management table which a relay station hold | maintains. The figure which shows the content of the reception MAC frame management table which a relay station hold | maintains. The figure which shows the content of the transmission MAC frame management table which a relay station hold | maintains. The figure for demonstrating an example which produces | generates a MAC frame using up the sequence number which must be used up. The figure which shows the content of the transmission MAC frame management table which a relay station hold | maintains. The figure for demonstrating the flow of a relay process. The figure for demonstrating one structural example of a relay station. The figure for demonstrating an example which produces | generates a MAC frame using up the sequence number which must be used up. The figure for demonstrating an example which produces | generates a MAC frame using up the sequence number which must be used up. The figure for demonstrating an example which produces | generates a MAC frame using up the sequence number which must be used up.

Explanation of symbols

201: Base station (BS)
202: Communication area 203: Relay station (RS)
204: Terminal (MS)
2702: Antenna 2703: RF processing unit 2704: Baseband reception digital processing unit 2705: Baseband transmission digital processing unit 2706: Communication control unit 2707: PHY / MAC frame processing unit 2708: Data buffer 2709: Reception MAC frame management table 2710: Transmission MAC frame management table 2711: header information extraction unit 2712: header information generation unit 2713: sequence number advance amount determination unit

Claims (10)

A relay station that relays communication from the first wireless communication device to the second wireless communication device, and has first data having a plurality of first segments each assigned a first sequence number, Receiving means for receiving from the first wireless communication device every time;
A plurality of the first segments received within a predetermined time are arranged in the order of the first sequence numbers and divided between the segments where the first sequence numbers are discontinuous, so that G (G is an integer of 2 or more) Group generation means for generating a group;
Re-segmentation means for concatenating the first segments for each group to generate concatenated data and re-segmenting the concatenated data into one or more second segments;
For the second segment included in the Mth (M is an integer greater than or equal to 2 and smaller than G) th group, the top is X + P (X is the second sequence number of the second segment at the end of the M−1th group) , P is an integer of 3 or more) sequence number giving means for giving the second sequence numbers consecutive,
Transmitting means for transmitting the second segment to the second wireless communication device;
Relay station equipped with. The receiving means includes, after the predetermined time, a first sequence number of a first segment located at the end of the M-1th group and a first sequence number of a first segment located at the beginning of the Mth group. Receive a first segment with a first sequence number between and
The segment generating means generates second connected data by connecting the first segments received after the predetermined time by the receiving means, and converts the second connected data into P-1 second segments. Re-segment,
2. The relay station according to claim 1, wherein the sequence number assigning unit assigns consecutive second sequence numbers of X + 1 to X + P−1 to the P−1 second segments. The receiving means includes, after the predetermined time, a first sequence number of a first segment located at the end of the M-1th group and a first sequence number of a first segment located at the beginning of the Mth group. Receive a first segment with a first sequence number between and
The segment generation unit generates the second connection data by connecting the first segments received by the reception unit after the predetermined time, and generates the second connection data by a second number greater than P-1. Re-segment into segments,
The sequence number assigning means assigns X + 1 to X + P-2 consecutive second sequence numbers to the second segment from the first to the P-2th, and all the second segments after the P-1th are X + P-. The relay station according to claim 1, wherein a second sequence number of 1 is assigned in common. The receiving means includes, after the predetermined time, a first sequence number of a first segment located at the end of the M-1th group and a first sequence number of a first segment located at the beginning of the Mth group. Receive a first segment with a first sequence number between and
The segment generation unit generates the second connection data by connecting the first segments received by the reception unit after the predetermined time, and generates the second connection data as R number less than P−1. Re-segment into two segments,
The sequence number assigning means assigns consecutive second sequence numbers X + 1 to X + R to the R second segments, and assigns second sequence numbers X + R + 1 to X + P-1 to dummy data, respectively.
The relay station according to claim 1, wherein the segment transmission unit transmits the dummy data in addition to the second segment. The value of P is a value obtained by subtracting the value of the first sequence number of the last segment of the M-1th group from the value of the first sequence number of the first segment of the Mth group. The relay station according to claim 1, wherein the relay station is a relay station. The total size information up to the immediately preceding first segment is added to each of the first segments,
The sequence number assigning means uses the total size information, the first sequence number of the first segment located at the end of the M-1th group, and the first segment located at the beginning of the Mth group Calculating the total size V of the first segments having a first sequence number between
The value of the P is a minimum integer equal to or greater than a value obtained by dividing the V by the H, where H is a size of a second segment that can be transmitted at a predetermined minimum transmission rate. The relay station according to any one of 1 to 4. The total size information up to the immediately preceding first segment is added to each of the first segments,
The sequence number assigning means uses the total size information, the first sequence number of the first segment located at the end of the M-1th group, and the first segment located at the beginning of the Mth group Calculating the total size V of the first segments having a first sequence number between
Calculating an average segment size W of the first segment group received within the predetermined time period;
The relay station according to any one of claims 1 to 4, wherein the value of P is a value obtained by adding 1 to a minimum integer equal to or greater than a value obtained by dividing the V by the W. The sequence number assigning means, after the predetermined time, includes a first sequence number of a first segment located at the end of the M−1th group and a first segment number located at the beginning of the Mth group. Assuming that a first segment having a first sequence number between the sequence numbers is received at the predetermined time, the number of segments Z generated by re-segmentation of the concatenated data of these first segments And determine the value of P to be Z + 1.
The relay station according to claim 1, wherein the relay station is a relay station. The relay station according to any one of claims 1 to 8, wherein the predetermined fixed time is a time frame section defined by a system. A relay method executed in a relay station that relays communication from a first wireless communication apparatus to a second wireless communication apparatus, wherein first data having a plurality of first segments each assigned a first sequence number Receiving a segment from the first wireless communication device for each first segment;
A plurality of the first segments received within a predetermined time are arranged in the order of the first sequence numbers and divided between the segments where the first sequence numbers are discontinuous, so that G (G is an integer of 2 or more) A group generation step for generating a group;
Re-segmenting the first segment for each group to generate concatenated data and re-segment the concatenated data into one or more second segments;
For the second segment included in the Mth (M is an integer greater than or equal to 2 and smaller than G) th group, the top is X + P (X is the second sequence number of the second segment at the end of the M−1th group) , P is an integer greater than or equal to 3) and the sequence number assigning step for assigning the second sequence numbers consecutively starts with,
Transmitting the second segment to the second wireless communication device;
Relay method with.

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