JP5713130B2 - Communication section setting method, relay station, mobile station, mobile communication system - Google Patents

Description

  The present invention relates to a relay technology for wireless communication between a base station and a mobile station.

  In cellular mobile communication systems, progress is being made from UMTS (Universal Mobile Telecommunication System) to LTE (Long Term Evolution). LTE employs OFDM (Orthogonal Frequency Division Multiplexing) and SC-FDMA (Single Carrier-Frequency Division Multiple Access) as downlink and uplink radio access technologies, respectively, with a downlink peak transmission rate of 100 Mb / s or more and uplink. High-speed wireless packet communication with a peak transmission rate of 50 Mb / s or more is possible. The 3GPP (3rd Generation Partnership Project), an international standardization organization, is currently examining LTE-A (LTE-Advanced), a mobile communication system based on LTE, for further high-speed communication. LTE-A aims for a downlink peak transmission rate of 1 Gb / s and an uplink peak transmission rate of 500 Mb / s, and various new technologies are being studied for radio access systems and network architectures ( Non-patent documents 1 to 3). On the other hand, since LTE-A is a system based on LTE, it is attempted to maintain backward compatibility.

  As one of the methods for performing high-speed data communication, a method of introducing a relay node (RN) as shown in FIG. 1 to support communication between a base station and a mobile station has been studied (non-patented). Reference 2). A relay station relays between a base station (Doner eNB or eNB) and a mobile station (UE: User Equipment), and is installed in order to support high-speed data communication. As shown in FIG. 2, the link between the mobile station UE and the relay station RN is referred to as Uu, and the link between the base station (eNB) and the relay station (RN) is referred to as Un. In the following description, Uu may be referred to as an access link and Un as a backhaul link.

  Various systems can be considered as the form of the relay station, but the repeater system, decode & forward system, L2 system and L3 system are mainly studied. Here, the repeater relay station has only a function of amplifying a radio signal (data signal and noise). A decode & forward relay station has a function of amplifying only a data signal from radio signals. An L2 relay station has L2 functions such as a MAC layer. An L3 relay station has L3 functions such as an RRC layer and operates in the same manner as a base station. Note that an L3 relay station is called Type 1 RN in LTE-A.

  A method of deploying relay stations in cells is also being studied. For example, a deployment method in which a relay station is installed at the cell edge for the purpose of increasing the throughput at the cell edge, or a relay station is installed in a range (dead zone) where radio waves from the base station do not reach locally in the cell Deployment methods are mainly being studied.

    When transmitting and receiving data between a base station and a mobile station via an L3 relay station (Type1 RN), the same frequency band is set between the base station and the relay station, and between the relay station and the mobile station. In the case of inband relaying, it is preferable to prevent self-interference at the relay station. Self-interference (or “wraparound interference”) means that when a relay station receives downlink data addressed to itself from the base station, for example, and transmits downlink data addressed to the mobile station from the own station, This means that the transmission data goes around to the receiving section of its own station and interferes with the data from the base station. Similarly, in the case of uplink data, self-interference can occur. When self-interference occurs, the relay station cannot receive data correctly.

In order to overcome this self-interference problem, LTE-A has been studied under the following policy (Non-patent Document 2).
(A) Downlink: The relay station does not perform data transmission addressed to the mobile station in a downlink backhaul (DL backhaul) that is a subframe in which data is received from an upper base station.

(B) Uplink: The relay station does not perform data reception from the mobile station in the uplink backhaul (UL backhaul), which is a subframe for transmitting data to the upper base station.
Based on the above policy (A), when a downlink backhaul is set between the relay station and the base station as shown in FIG. 3, the subframe between the relay station and the mobile station is MBSFN (Multicast / Broadcast over Single Frequency Network) subframe. This is due to the following reason. That is, in the MBSFN subframe, the LTE compatible mobile station does not receive unicast data. Therefore, since the mobile station UE does not receive a part of the reference signal, it is not necessary to perform unnecessary measurement of the reference signal in the mobile station. More precisely, the relay station transmits PDCCH (Physical Downlink Control Channel), PHICH (Physical Hybrid ARQ Indicator Channel), and PCFICH (Physical Control Format Indicator Channel) as control signals addressed to the mobile station in the downlink backhaul. It is possible, but PDSCH cannot be transmitted. In order to receive the control signal, a reference signal is arranged in the first half of the MBSFN subframe (CTRL section in FIG. 3), but no reference signal is arranged in the second half of the MBSFN subframe.

  Based on the above policy (B), the relay station is controlled not to give an uplink data transmission permission (UL grant) to the mobile station 4 subframes (4 ms) before the uplink backhaul. This is to avoid the fact that if the mobile station is permitted to transmit uplink data within 4 ms of the uplink backhaul, the mobile station transmits data to the relay station via the uplink backhaul.

  Further, the relay station is controlled not to execute downlink data transmission to the mobile station 4 subframes (4 ms) before the uplink backhaul. This is due to the following reason. That is, LTE HARQ (Hybrid Automatic Repeat reQuest) stipulates that a transmission destination station returns an ACK / NACK signal 4 ms (for four subframes) after one station transmits data. Therefore, if the downlink data is transmitted to the mobile station in 4 ms of the uplink backhaul, the mobile station transmits an ACK / NACK signal to the relay station via the uplink backhaul.

  In uplink backhaul, PUCCH (Physical Uplink Control Channel) and PUSCH (physical uplink shared channel), which are control signals for relay stations, can be transmitted, but PUCCH and PUSCH, which are control signals transmitted by the mobile station, are transmitted. Cannot send.

3GPP TR 36.913 V8.0.1 (2009-03), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LTE-Advanced) (Release 8) 3GPP TR 36.912 V9.0.0 (2009-09), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Feasibility study for Further Advancements for E-UTRA (LTE-Advanced) (Release 9) 3GPP TS 36.133 V9.2.0 (2009-12), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for support of radio resource management (Release 9)

  As shown in Non-Patent Document 2, although the backhaul has been discussed for LTE-A, studies on which subframes in the radio frame should be set for downlink and uplink backhaul in LTE-A are underway. It has been. Therefore, if the backhaul is always fixed and set at the same subframe position in the radio frame, considering the relationship with the execution timing of HARQ (Hybrid Automatic Repeat reQuest), the following problems are encountered. is there. Hereinafter, this problem will be described in more detail. In the following description, as shown in FIG. 4, a 10 ms radio frame (Frame) is composed of 10 subframes # 0 to # 9 each having a 1 ms section as a TTI (Transmission Time Interval). It shall be.

  An example in which the backhaul is always set to the same subframe position in the radio frame will be described with reference to FIG. In FIG. 5, (a) is a downlink backhaul DL_BH, (b) is a downlink access link DL_AL, (c) is an uplink backhaul UL_BH, and (d) in consecutive frames (Frame_0, Frame_1, Frame_2, Frame_3,...). Is the uplink access link UL_AL, and (e) is the HARQ process (process number PID1,..., PID8) of the access link. In FIG. 5, a downward arrow indicates transmission of a downstream signal, and an upward arrow indicates transmission of an upstream signal.

  In FIGS. 5A to 5D, black positions indicate that a backhaul or access link cannot be set. For example, in FIG. 5A, since downlink access links are used for transmitting control information in subframes # 0, # 4, # 5, and # 9, a downlink backhaul cannot be set in these subframes. . Therefore, in this example, the downlink backhaul is set in subframe # 1 in all consecutive frames. According to LTE regulations, an ACK / NACK signal (A / N) is sent back 4 ms after data transmission (data), so that the relay station for data transmission of the base station eNB in subframe # 1 RN returns an ACK / NACK signal (A / N) to subframe # 5. Therefore, in FIG. 5C, an uplink backhaul is set in subframe # 5. In FIGS. 5A and 5C, the downstream or upstream backhaul section is highlighted with a solid bold line.

  If a downlink backhaul is set in subframe # 1 and an uplink backhaul is set in subframe # 5, an access link cannot be set in the same subframe. Therefore, as shown in FIGS. 5B and 5D, the position of subframe # 1 is displayed in black on the downlink access link (cannot be set), and the position of subframe # 5 is displayed on the uplink access link. Is displayed in black (cannot be set).

  As shown in FIG. 5, there are two problems when the backhaul is always set at the same subframe position within one frame.

  The first problem is that backward compatibility with LTE is lost. As described above, according to LTE regulations, an ACK / NACK signal (A / N) is returned 4 ms after data transmission (data), but when a backhaul as shown in FIG. 5 is set, An ACK / NACK signal is returned after 6 ms, and the LTE specification is not satisfied. In the example of FIG. 5, the ACK / NACK signal from the base station eNB for data transmission of the uplink backhaul (subframe # 5) is the downlink backhaul (subframe # 1) of the next frame. However, if it is not necessary to maintain backward compatibility with LTE regarding the HARQ return timing, this is not a big problem.

  Next, the second problem is that, in the backhaul configuration shown in FIG. 5, the HARQ process and its sections in which the HARQ of the access link cannot be used are scattered, and efficient scheduling of the access link is performed in the relay station RN. It will be difficult.

  In the example shown in FIG. 5, some of the HARQ processes (4 locations; indicated by bold lines) with process numbers PID2, PID4, PID6, and PID8 cannot be used. That is, in the HARQ process with process numbers PID2, PID4, PID6, and PID8, the access link cannot be used because the uplink data transmission timing matches the uplink backhaul of frames Frame_2, Frame_3, Frame_0, and Frame_1. Therefore, when new data transmission is performed, a schedule is set while avoiding specific sections of the unavailable HARQ process which are scattered as shown in FIG. Therefore, the complexity of scheduling increases and the efficiency of the access link decreases.

  In view of the above, in one aspect of the invention, in setting a communication section between a base station and a relay station in a mobile communication system including a relay station that relays wireless communication between the base station and the mobile station, It is an object of the present invention to provide a communication section setting method, a relay station, a mobile station, and a mobile communication system that suppress a decrease in link efficiency.

  According to one aspect of the present disclosure, a communication section setting method in a mobile communication system including a relay station that relays wireless communication between a base station and a mobile station, wherein a transmission subframe from the relay station to the mobile station In the section that becomes the MBSFN subframe, the relay station receives the transmission signal from the base station, and the relay station transmits the signal to the base station by limiting the transmission of the signal from the mobile station to the relay station. At least one of the uplink communication sections to be transmitted is set, and communication processing including data transmission and an acknowledgment after the data transmission is managed on the access link between the mobile station and the relay station A plurality of communication processes are provided, and the upstream data of the specific communication process is limited to a specific communication process among the plurality of communication processes. Can set the uplink communication section at a timing corresponding to the signal timing, after a predetermined time of each uplink communication section set, it sets the downlink communication path comprises a communication section setting method is provided.

  According to the present disclosure, in setting a communication section between a base station and a relay station in a mobile communication system including a relay station that relays wireless communication between the base station and the mobile station, the efficiency of the access link is reduced. Can be suppressed.

The block diagram of the mobile communication system containing the relay station for supporting communication of a base station and a mobile station. The figure which shows the link structure between a base station, a relay station, and a mobile station. The figure which shows the setting guideline of a well-known backhaul. The figure for demonstrating the structure of 1 frame. The figure for demonstrating the problem at the time of setting backhaul always to the position of the same sub-frame within a radio | wireless frame. The figure for demonstrating the setting conditions in the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 1st Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which shows an example of the backhaul setting method of 2nd Embodiment. The figure which arranged the backhaul set by the backhaul setting method illustrated to FIGS. 8-1 to 8-8. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which shows an example of the backhaul setting method of 3rd Embodiment. The figure which arranged the backhaul set by the backhaul setting method illustrated to FIGS. 10-1 to 10-8. The figure which shows an example of the area of Measurement gap set in 4th Embodiment. The block diagram which shows schematic structure of the relay station of 5th Embodiment. The block diagram which shows schematic structure of the mobile station of 5th Embodiment. The flowchart which shows an example of operation | movement of the relay station of 5th Embodiment. The flowchart which shows an example of operation | movement of the relay station of 5th Embodiment. The flowchart which shows an example of operation | movement of the mobile station of 5th Embodiment. The flowchart which shows an example of operation | movement of the mobile station of 5th Embodiment.

  Hereinafter, a plurality of embodiments will be described. In the following description, the base station is abbreviated as eNB, the relay station is RN, and the mobile station is abbreviated as appropriate. The base station eNB of the present embodiment is a donor base station (Donor eNB or DeNB) that supports a backhaul with the relay station RN. HARQ is appropriately referred to as indicating a process (first communication process) including data transmission and a confirmation response after a predetermined time from the data transmission.

  In the following description, “backhaul section” refers to one or a plurality of sections among a plurality of sections set in units of TTI (Transmission Time Interval) in a single radio frame. . In the present embodiment, the TTI is a time in units of subframes (1 ms). “Setting a backhaul” may mean setting or specifying a backhaul as a subframe in a radio frame. Note that this embodiment is applicable even when the TTI is not a time in units of subframes.

(1) 1st Embodiment Hereinafter, the backhaul setting method of 1st Embodiment is demonstrated.
The backhaul setting method of this embodiment is a method in the case where backward compatibility with LTE is maintained with respect to HARQ return timing. That is, here, regarding the HARQ return timing, it is assumed that an ACK / NACK signal (A / N; confirmation response) is returned 4 ms after data transmission (data). This backhaul configuration method is intended to reduce the number of HARQ processes (communication processes) that are partially unavailable, to reduce the complexity of the schedule, and to improve the efficiency of the access link. Yes.

First, setting conditions for the backhaul setting method of the present embodiment will be described with reference to FIG. FIG. 6 is a diagram of the same format as FIG. 5 described above.
That is, in FIG. 6, in consecutive frames (Frame_0, Frame_1, Frame_2, Frame_3,...), (A) is the downlink backhaul DL_BH, (b) is the downlink access link DL_AL, (c) is the uplink backhaul UL_BH, ( d) shows the uplink access link UL_AL, and (e) shows the HARQ process (process number PID1,..., PID8) as the communication process of the access link, respectively, in units of 1 ms, or the operation timing. In FIG. 6, a downward arrow indicates transmission of a downstream signal, and an upward arrow indicates transmission of an upstream signal.

  In FIGS. 6A to 6D, black positions indicate that a backhaul link or access link cannot be set. In FIGS. 6A to 6D, a subframe surrounded by a solid thick frame line means that a backhaul or an access link is secured in the subframe.

  Specifically, in LTE, subframes # 0, # 4, # 5, and # 9 are used for the Primary Synchronization Channel, Paging, Secondary Synchronization Channel, and Paging, respectively, in the downlink access link. Downlink backhaul cannot be set in the frame. Therefore, in the downlink backhaul DL_BH, subframes # 0, # 4, # 5, and # 9 are painted black in each frame, and in the downlink access link DL_AL, subframes # 0, # 4, and # 5 are included in each frame. , # 9 is surrounded by a solid thick border. Furthermore, 4ms after transmission from relay station RN on downlink access links of subframes # 0, # 4, # 5, and # 9, the uplink access link is used to return the ACK / NACK signal (A / N). Is done. Therefore, in the uplink access link UL_AL, subframes # 4, # 8, # 9, and # 3 are surrounded by solid bold lines in each frame, and in the uplink backhaul UL_BH, subframes # 4, # 8 are included in each frame. , # 9, # 3 are painted black.

  Next, based on the setting conditions for the backhaul setting method shown in FIG. 6, a specific backhaul setting method of the present embodiment will be described with reference to FIGS. FIGS. 7-1 to 7-8 are diagrams of the same format as FIG. FIGS. 7-1 to 7-8 show a case where the HARQ processes having process numbers PID1 to PID8 are at least partially unavailable HARQ processes. In FIGS. 7-1 to 7-8, the timing of HARQ that cannot be executed is indicated by a bold line.

  FIG. 7A illustrates a backhaul setting method in a case where only the HARQ process with the process number PID1 among the HARQ processes with the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID1.

  In FIG. 7A, 3 backhauls are secured in 4 consecutive frames. That is, in FIG. 7A, the downlink backhaul is set in subframe # 2 of frame Frame_1, subframe # 8 of frame Frame_2, and subframe # 6 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 6 of Frame_1, subframe # 2 of frame Frame_3, and subframe # 0 of frame Frame_0 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7A, all the HARQ that cannot be executed (the execution timing of the thick line) are the same HARQ process (that is, process number PID1). Belonging to.

  FIG. 7-2 illustrates a backhaul setting method in a case where only the HARQ process with the process number PID2 among the HARQ processes with the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID2.

  In FIG. 7-2, 3 backhauls are secured in 4 consecutive frames. That is, in FIG. 7-2, a downlink backhaul is set in subframe # 3 of frame Frame_1, subframe # 1 of frame Frame_2, and subframe # 7 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 1 in Frame_0, subframe # 7 in frame Frame_1, and subframe # 5 in frame Frame_2.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-2, all the HARQ that cannot be executed (the execution timing of the thick line) is the same HARQ process (that is, process number PID2) Belonging to.

  FIG. 7C illustrates a backhaul setting method in a case where only the HARQ process having the process number PID3 among the HARQ processes having the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID3.

  In FIG. 7-3, three backhauls are secured in four consecutive frames. That is, in FIG. 7C, a downlink backhaul is set in subframe # 6 of frame Frame_0, subframe # 2 of frame Frame_2, and subframe # 8 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, It is set to subframe # 2 of Frame_0, subframe # 0 of frame Frame_1, and subframe # 6 of frame Frame_2.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-3, all the HARQ that cannot be executed (the execution timing of the thick line) is the same HARQ process (that is, process number PID3) Belonging to.

  FIG. 7-4 illustrates a backhaul setting method in a case where only the HARQ process with process number PID4 among the HARQ processes with process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID4.

  In FIG. 7-4, 3 backhauls are secured in 4 consecutive frames. That is, in FIG. 7-4, a downlink backhaul is set in subframe # 7 of frame Frame_0, subframe # 3 of frame Frame_2, and subframe # 1 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 1 of Frame_1, subframe # 7 of frame Frame_2, and subframe # 5 of frame Frame_3 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-4, all the HARQ that cannot be executed (the execution timing of the thick line) is the same HARQ process (that is, process number PID4) Belonging to.

  FIG. 7-5 shows a backhaul setting method when only the HARQ process with the process number PID5 among the HARQ processes with the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID5.

  In FIG. 7-5, three downstream backhauls are secured in four consecutive frames. That is, in FIG. 7-5, downlink backhaul is set in subframe # 8 of frame Frame_0, subframe # 6 of frame Frame_1, and subframe # 2 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 2 of Frame_1, subframe # 0 of frame Frame_2, and subframe # 6 of frame Frame_3 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-5, all the HARQ that cannot be executed (the execution timing of the thick line) is the same HARQ process (that is, process number PID5) Belonging to.

  FIG. 7-6 illustrates a backhaul setting method in a case where only the HARQ process having the process number PID6 among the HARQ processes having the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID6.

  In FIG. 7-6, three backhauls are secured in four consecutive frames. That is, in FIG. 7-6, a downlink backhaul is set in subframe # 1 of frame Frame_0, subframe # 7 of frame Frame_1, and subframe # 3 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 5 of Frame_0, subframe # 1 of frame Frame_2, and subframe # 7 of frame Frame_3 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-6, all the HARQ that cannot be executed (the execution timing of the thick line) are the same HARQ process (that is, process number PID6) Belonging to.

  FIG. 7-7 shows a backhaul setting method in a case where only the HARQ process with the process number PID7 among the HARQ processes with the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID7.

  In FIG. 7-7, the downlink backhaul is secured 3 times out of 4 consecutive frames. That is, in FIG. 7-7, a downlink backhaul is set in subframe # 2 of frame Frame_0, subframe # 8 of frame Frame_1, and subframe # 6 of frame Frame_2. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 6 of Frame_0, subframe # 2 of frame Frame_2, and subframe # 0 of frame Frame_3 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-7, all the unexecutable HARQ (execution timing of bold lines) are the same HARQ process (that is, process number PID7) Belonging to.

  FIG. 7-8 illustrates a backhaul setting method in a case where only the HARQ process with the process number PID8 among the HARQ processes with the process numbers PID1 to PID8 cannot partially execute HARQ. That is, the HARQ process in which HARQ cannot be partially executed is limited to the process number PID8.

  7-8, three backhauls are secured in four consecutive frames. That is, in FIG. 7-8, a downlink backhaul is set in subframe # 3 of frame Frame_0, subframe # 1 of frame Frame_1, and subframe # 7 of frame Frame_2. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 7 of Frame_0, subframe # 5 of frame Frame_1, and subframe # 1 of frame Frame_3 are set.

  In this uplink backhaul, the uplink access link cannot be used, but as shown in (e) of FIG. 7-8, all the HARQ that cannot be executed (the execution timing of the thick line) is the same HARQ process (that is, process number PID8) Belonging to.

  As described above, in the backhaul setting method of the present embodiment, the backhaul is set so that the number of HARQ processes in which the HARQ of the uplink access link cannot be partially executed is limited to one. Therefore, although the frequency of backhaul setting (3 times out of 4 frames) is relatively low, HARQ processes that cannot partially execute HARQ on the uplink link are aggregated to reduce scheduling complexity, and Access link efficiency is improved.

(2) Second Embodiment Hereinafter, a backhaul setting method according to a second embodiment will be described.
The backhaul setting method of this embodiment is a method in the case where backward compatibility with LTE is maintained with respect to HARQ return timing. That is, here, regarding the HARQ return timing, it is assumed that an ACK / NACK signal (A / N) is returned 4 ms after data transmission (data). This embodiment is different from the first embodiment in that the frequency of setting the backhaul is increased. Thereby, compared with the case of 1st Embodiment, it is aimed at maintaining the efficiency of an access link, increasing the setting frequency of a backhaul more.

  Hereinafter, a specific backhaul setting method of the present embodiment will be described with reference to FIGS. 8-1 to 8-8. FIGS. 8-1 to 8-8 are diagrams of the same format as FIG. FIGS. 8-1 to 8-8 illustrate a case where the HARQ processes having process numbers PID1 to PID8 are HARQ processes that cannot execute HARQ at all timings. In FIGS. 8-1 to 8-8, the timing of HARQ that cannot be executed is indicated by a bold line. In FIGS. 8-1 to 8-8, contrary to the setting conditions shown in FIG. 6, the position of the subframe that cannot be used as the uplink access link is displayed with a thick black dotted line and painted black. .

  In the backhaul setting method shown in FIGS. 8-1 to 8-8, the downlink backhaul is added to the backhaul setting method shown in FIGS. A backhaul is secured. In each of the backhaul setting methods shown in FIGS. 8-1 to 8-8, the number of uplink backhauls is ensured by setting HARQ processes that cannot execute HARQ at all timings.

  In the backhaul setting method illustrated in FIG. 8A, a downlink backhaul is newly set in the subframe # 8 of the frame Frame_0 as compared with the method illustrated in FIG. 7A. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 2 of frame Frame_1.

  Further, by setting the HARQ process with process number PID1 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, an uplink backhaul is set in subframe # 8 of frame Frame_0 and subframe # 4 of frame Frame_2 corresponding to the uplink access link in the HARQ process of process number PID1. Furthermore, in order to enable reception of an ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 8 of frame Frame_0), the frame Frame_0 4ms before that is received. Uplink backhaul is set in subframe # 4. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in (e) of FIG. 8A, the HARQ process that cannot execute HARQ is shifted by 4 ms from some HARQ processes (PID1 and PID1). PID5). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8B, a downlink backhaul is newly set in the subframe # 1 of the frame Frame_0 as compared with the method illustrated in FIG. 7B. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Set to subframe # 5 of frame Frame_0.

  Also, by setting the HARQ process with process number PID2 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, an uplink backhaul is set in subframe # 9 of frame Frame_0 and subframe # 3 of frame Frame_3 corresponding to the uplink access link in the HARQ process of process number PID2. Furthermore, in order to enable reception of the ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 1 of frame Frame_0), the frame Frame_3 4ms before that is received. Uplink backhaul is set in subframe # 7. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 8E, the HARQ process that cannot execute HARQ is shifted by 4 ms from some HARQ processes (PID2 and PID2). PID6). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8C, a downlink backhaul is newly set in the subframe # 8 of the frame Frame_1 as compared with the method illustrated in FIG. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 2 of frame Frame_2.

  Further, by setting the HARQ process with process number PID3 as the HARQ process in which HARQ cannot be executed at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 8 of frame Frame_1 and subframe # 4 of frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID3 are set as the uplink backhaul. Furthermore, in order to enable reception of an ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 8 of the frame Frame_1), the frame Frame_1 4ms before that is received. Uplink backhaul is set in subframe # 4. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in (e) of FIG. 8-3, HARQ processes that cannot execute HARQ are shifted by 4 ms from some HARQ processes (PID3 and PID3). PID7). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8D, a downlink backhaul is newly set in the subframe # 1 of the frame Frame_1 as compared with the method illustrated in FIG. 7D. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 5 of frame Frame_1.

  Also, by setting the HARQ process with process number PID4 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 3 of frame Frame_0 and subframe # 9 of frame Frame_1 corresponding to the uplink access link in the HARQ process with process number PID4 are set as the uplink backhaul. Further, in order to enable reception of an ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 1 of the frame Frame_1), the frame Frame_0 4ms before that is received. Uplink backhaul is set in subframe # 7. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in (e) of FIG. 8-4, HARQ processes that cannot execute HARQ are shifted by 4 ms from some HARQ processes (PID4 and PID4). PID8). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8-5, a downlink backhaul is newly set in the subframe # 8 of the frame Frame_2 as compared with the method illustrated in FIG. 7-5. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 2 of frame Frame_3.

  Further, by setting the HARQ process with process number PID5 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 4 of frame Frame_0 and subframe # 8 of frame Frame_2 corresponding to the uplink access link in the HARQ process with process number PID5 are set as the uplink backhaul. Further, in order to enable reception of an ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 8 of the frame Frame_2), the frame Frame_2 4ms before that is received. Uplink backhaul is set in subframe # 4. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in (e) of FIG. 8-5, HARQ processes that cannot execute HARQ are shifted by 4 ms from some HARQ processes (PID5 and PID5). PID1). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8-6, a downlink backhaul is newly set in the subframe # 1 of the frame Frame_2 as compared with the method illustrated in FIG. 7-6. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 5 of frame Frame_2.

  Further, by setting the HARQ process with process number PID6 as the HARQ process in which HARQ cannot be executed at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 3 of frame Frame_1 and subframe # 9 of frame Frame_2 corresponding to the uplink access link in the HARQ process of process number PID6 are set as the uplink backhaul. Furthermore, in order to enable reception of the ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 1 of the frame Frame_2), the frame Frame_1 4ms before that is received. Uplink backhaul is set in subframe # 7. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 8E (e), HARQ processes that cannot execute HARQ are shifted by 4 ms from some HARQ processes (PID6 and PID6). PID2). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8-7, a downlink backhaul is newly set in the subframe # 8 of the frame Frame_3 as compared with the method illustrated in FIG. 7-7. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Is set to subframe # 2 of frame Frame_0.

  Also, by setting the HARQ process with process number PID7 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 4 of frame Frame_1 and subframe # 8 of frame Frame_3 corresponding to the uplink access link in the HARQ process of process number PID7 are set as the uplink backhaul. Furthermore, in order to enable reception of an ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 8 of frame Frame_3), the frame Frame_3 4ms before that is received. Uplink backhaul is set in subframe # 4. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 8E (e), the HARQ process that cannot execute HARQ is shifted by 4 ms from some HARQ processes (PID7 and PID7). PID3). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  In the backhaul setting method illustrated in FIG. 8-8, a downlink backhaul is newly set in the subframe # 1 of the frame Frame_3 as compared with the method illustrated in FIG. 7-8. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. As a result, in order to return an ACK / NACK signal (A / N) from the relay station RN after 4 ms after data transmission (data) from the base station eNB in this additionally set downlink backhaul, the uplink backhaul , Set to subframe # 5 of frame Frame_3.

  Also, by setting the HARQ process with process number PID8 as the HARQ process that cannot execute HARQ at all timings, a larger number of uplink backhauls can be secured. That is, subframe # 3 of frame Frame_2 and subframe # 9 of frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID8 are set as the uplink backhaul. Furthermore, in order to enable reception of the ACK / NACK signal (A / N) from the base station eNB in the additionally set downlink backhaul (subframe # 1 of the frame Frame_3), the frame Frame_2 4ms before that is received. Uplink backhaul is set in subframe # 7. In order to secure a larger number of uplink backhauls in this way, unlike the LTE-based setting conditions shown in FIG. 6, the newly configured uplink backhaul does not transmit via the uplink access link. Are controlled by the relay station RN.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 8E (e), HARQ processes that cannot execute HARQ are shifted by 4 ms from some HARQ processes (PID8 and PID8). PID4). Thereby, it is possible to set four downlink backhauls and seven uplink backhauls per four frames.

  FIG. 9 is a diagram in which the backhaul set by the backhaul setting method illustrated in FIGS. 8-1 to 8-8 is arranged. In FIG. 9, when the configuration is 0 to 7, it corresponds to the transmission / reception timing set in FIGS. 8-1 to 8-8, respectively. SFN (System Frame Number) means a frame number, and the frames of SFN satisfying SFN mod 4 = 0, 1, 2, 3 are frames Frame_0, 1, 2, 2 in FIGS. 8-1 to 8-8, respectively. It corresponds to 3.

  FIG. 9A shows subframe #i (i = 0,..., 9) in which the relay station RN receives the ACK / NACK signal for each configuration value, that is, the downlink backhaul #i. . An uplink backhaul is set in subframe # (i-4) 4 ms before subframe #i described here.

  FIG. 9B shows subframe #i (i = 0,..., 9) in which relay station RN transmits an ACK / NACK signal, that is, uplink backhaul #i. That is, the downlink backhaul is set in subframe # (i−4) 4 ms before subframe #i described here. The uplink backhaul not described in FIG. 9B is appropriately determined according to the value of each configuration, that is, the uplink transmission timing of the HARQ process to be aggregated.

  As described above, in the backhaul setting method of the present embodiment, in order to secure more setting frequency of downlink and uplink backhaul, among HARQ processes, HARQ processes that cannot execute HARQ are aggregated. did. This makes it possible to increase the frequency of setting the backhaul, facilitate scheduling on the access link in the relay station RN, and maintain both access link efficiency at a high level.

  For example, referring again to FIG. 8A, the downlink backhaul is not set 4 ms after the uplink backhaul set in the subframe # 2 of the frame Frame_1. For this reason, it is not preferable that the relay station RN transmits data (user data or the like) that requires a return of the ACK / NACK signal to the base station eNB through the uplink backhaul set in the subframe # 2 of the frame Frame_1. This is because the downlink backhaul is not set 4 ms after the uplink backhaul set in the subframe # 2 of the frame Frame_1. Therefore, in the uplink backhaul set by the backhaul setting method shown in FIGS. 8-1 to 8-8, in the case where the downlink backhaul is not set after 4 ms, the relay station RN is connected to the base station eNB. Send data that does not require a ACK / NACK signal response. The data that does not require the return of the ACK / NACK signal is, for example, data for CQI (Channel Quality Indicator) report.

  Although the data type transmitted in a part of the configured uplink backhaul is limited, it is possible to secure more uplink backhaul setting frequency by appropriately managing the data transmitted in each uplink backhaul. It can also be said.

(3) Third Embodiment Hereinafter, a backhaul setting method according to a third embodiment will be described.
In 2nd Embodiment, the example which ensured the downlink backhaul in each flame | frame was shown by providing an additional backhaul with respect to the backhaul set in 1st Embodiment. However, the downlink backhaul of each frame can be set arbitrarily. In other words, regarding the HARQ return timing, the number of HARQ processes that cannot execute HARQ partially or wholly, assuming that an ACK / NACK signal (A / N) is returned 4 ms after data transmission (data). What is necessary is just to set a backhaul as much as possible. An example different from the second embodiment of such a backhaul setting method will be described below.

  Hereinafter, a specific backhaul setting method of the present embodiment will be described with reference to FIGS. 10-1 to 10-8. 10-1 to 10-8 are diagrams of the same format as FIG. FIGS. 10-1 to 10-8 show the case where the HARQ process with process numbers PID1 to PID8 and the HARQ process with process numbers PID5 to PID8 shifted after 4 ms are partially HARQ processes that cannot execute HARQ. Show. In FIGS. 10-1 to 10-8, the timing of HARQ that cannot be executed is indicated by a bold line.

  The backhaul setting method shown in FIGS. 10-1 to 10-8 is different from the method shown in FIGS. 8-1 to 8-8 in that two HARQ processes that cannot partially execute HARQ are set. .

  In FIG. 10A, a downlink backhaul is secured in each of four consecutive frames. That is, in FIG. 10A, a downlink backhaul is set in subframe # 8 of frame Frame_0, subframe # 6 of frame Frame_1, subframe # 8 of frame Frame_2, and subframe # 6 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 2 in Frame_1, subframe # 0 in frame Frame_2, subframe # 2 in frame Frame_3, and subframe # 0 in frame Frame_0.

  Here, the HARQ process with process number PID1 and the HARQ process with process number PID5 shifted 4 ms after the HARQ process with process number PID1 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 4 of frame Frame_2 corresponding to the uplink access link in the HARQ process of process number PID1 and subframe # 4 of frame Frame_0 corresponding to the uplink access link in the HARQ process of process number PID5 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are included in some HARQ processes (PID1 and PID1). PID 5) shifted by 4ms is collected. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-2, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10-2, a downlink backhaul is set in subframe # 1 of frame Frame_0, subframe # 3 of frame Frame_1, subframe # 1 of frame Frame_2, and subframe # 3 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 5 in Frame_0, subframe # 7 in frame Frame_1, subframe # 5 in frame Frame_2, and subframe # 7 in frame Frame_3.

  Here, the HARQ process with process number PID2 and the HARQ process with process number PID6 shifted after 4 ms from the HARQ process with process number PID2 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 9 of frame Frame_0 corresponding to the uplink access link in the HARQ process with process number PID2 and subframe # 9 of frame Frame_2 corresponding to the uplink access link in the HARQ process with process number PID6 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of the setting of the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E, the HARQ process in which HARQ cannot be partially executed is a part of HARQ processes (PID2 and PID2). PID6) shifted by 4ms is aggregated. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-3, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10C, the downlink backhaul is set in subframe # 6 of frame Frame_0, subframe # 8 of frame Frame_1, subframe # 6 of frame Frame_2, and subframe # 8 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, It is set to subframe # 0 of Frame_1, subframe # 2 of frame Frame_2, subframe # 0 of frame Frame_3, and subframe # 2 of frame Frame_0.

  Here, the HARQ process with process number PID3 and the HARQ process with process number PID7 shifted after 4 ms from the HARQ process with process number PID3 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 4 in frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID3 and subframe # 4 in frame Frame_1 corresponding to the uplink access link in the HARQ process with process number PID7 Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of the setting of the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are included in some HARQ processes (PID3 and PID3). PID 7) shifted by 4 ms. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-4, a downlink backhaul is secured in each of four consecutive frames. That is, in FIG. 10-4, a downlink backhaul is set in subframe # 3 of frame Frame_0, subframe # 1 of frame Frame_1, subframe # 3 of frame Frame_2, and subframe # 1 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 7 in Frame_0, subframe # 5 in frame Frame_1, subframe # 7 in frame Frame_2, and subframe # 5 in frame Frame_3.

  Here, the HARQ process with process number PID4 and the HARQ process with process number PID8 shifted 4 ms after the HARQ process with process number PID4 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 9 of frame Frame_1 corresponding to the uplink access link in the HARQ process with process number PID4 and subframe # 9 of frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID8 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are part of HARQ processes (from PID4 and PID4). PID 8) shifted by 4ms is collected. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-5, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10-5, a downlink backhaul is set in subframe # 8 of frame Frame_0, subframe # 6 of frame Frame_1, subframe # 8 of frame Frame_2, and subframe # 6 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 2 in Frame_1, subframe # 0 in frame Frame_2, subframe # 2 in frame Frame_3, and subframe # 0 in frame Frame_0.

  Here, the HARQ process with process number PID5 and the HARQ process with process number PID1 shifted after 4 ms from the HARQ process with process number PID5 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 4 in frame Frame_0 corresponding to the uplink access link in the HARQ process with process number PID5 and subframe # 4 in frame Frame_2 corresponding to the uplink access link in the HARQ process with process number PID1 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are part of HARQ processes (from PID5 and PID5). PID1) shifted by 4ms is aggregated. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-6, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10-6, the downlink backhaul is set in subframe # 1 of frame Frame_0, subframe # 3 of frame Frame_1, subframe # 1 of frame Frame_2, and subframe # 3 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 5 in Frame_0, subframe # 7 in frame Frame_1, subframe # 5 in frame Frame_2, and subframe # 7 in frame Frame_3.

  Here, the HARQ process with process number PID6 and the HARQ process with process number PID2 shifted after 4 ms from the HARQ process with process number PID6 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 9 of frame Frame_2 corresponding to the uplink access link in the HARQ process with process number PID6 and subframe # 9 of frame Frame_0 corresponding to the uplink access link in the HARQ process with process number PID2 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are part of HARQ processes (PID6 and PID6). 4ID shifted PID2). Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-7, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10-7, the downlink backhaul is set in subframe # 6 of frame Frame_0, subframe # 8 of frame Frame_1, subframe # 6 of frame Frame_2, and subframe # 8 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, It is set to subframe # 0 of Frame_1, subframe # 2 of frame Frame_2, subframe # 0 of frame Frame_3, and subframe # 2 of frame Frame_0.

  Here, the HARQ process with process number PID7 and the HARQ process with process number PID3 shifted after 4 ms from the HARQ process with process number PID7 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 4 in frame Frame_1 corresponding to the uplink access link in the HARQ process with process number PID7 and subframe # 4 in frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID3 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are part of HARQ processes (from PID7 and PID7). 4ID shifted PID3). Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  In FIG. 10-8, a downlink backhaul is secured in each of the four consecutive frames. That is, in FIG. 10-8, the downlink backhaul is set in subframe # 3 of frame Frame_0, subframe # 1 of frame Frame_1, subframe # 3 of frame Frame_2, and subframe # 1 of frame Frame_3. Downstream backhaul is set at the same position for frames following frames Frame_0 to Frame_3. In order to return an ACK / NACK signal (A / N) from the relay station RN 4 ms after data transmission (data) from the base station eNB in the downlink backhaul set in this way, Subframe # 7 in Frame_0, subframe # 5 in frame Frame_1, subframe # 7 in frame Frame_2, and subframe # 5 in frame Frame_3.

  Here, the HARQ process with process number PID8 and the HARQ process with process number PID4 shifted after 4 ms from the HARQ process with process number PID8 are set as HARQ processes that cannot partially execute HARQ. As a result, a larger number of uplink backhauls can be secured. That is, subframe # 9 of frame Frame_3 corresponding to the uplink access link in the HARQ process with process number PID8 and subframe # 9 of frame Frame_1 corresponding to the uplink access link in the HARQ process with process number PID4 are transmitted to the uplink backhaul. Is set. Although different from the LTE-based setting conditions shown in FIG. 6, the relay station RN controls the part of the configured uplink backhaul so that transmission via the uplink access link is not performed.

  As a result of setting the downlink backhaul and the uplink backhaul in this way, as shown in FIG. 10E (e), HARQ processes in which HARQ cannot be partially executed are part of HARQ processes (from PID8 and PID8). PID 4) shifted by 4 ms. Accordingly, it is possible to set four down backhauls and six up backhauls per four frames.

  FIG. 11 is a diagram in which the backhaul set by the backhaul setting method illustrated in FIGS. 10-1 to 10-8 is arranged. In FIG. 11, when the configuration is 0 to 7, it corresponds to the transmission / reception timing set in FIGS. 10-1 to 10-8. SFN frames in which SFN mod 4 = 0, 1, 2, 3 is established correspond to frames Frame_0, 1, 2, 3 in FIGS. 10-1 to 10-8, respectively.

  FIG. 11A shows subframe #i (i = 0,..., 9) in which the relay station RN receives the ACK / NACK signal, that is, the downlink backhaul #i, for each configuration value. . An uplink backhaul is set in subframe # (i-4) 4 ms before subframe #i described here.

  FIG. 11B shows subframe #i (i = 0,..., 9) in which relay station RN transmits an ACK / NACK signal, that is, uplink backhaul #i. That is, the downlink backhaul is set in subframe # (i−4) 4 ms before subframe #i described here. The uplink backhaul not described in FIG. 11B is appropriately determined according to the value of each configuration, that is, the uplink transmission timing of the HARQ process to be aggregated.

  As described above, in the backhaul setting method of the present embodiment, in order to secure as many downlink and uplink backhaul setting frequencies as possible, among HARQ processes, HARQ processes that cannot execute HARQ are aggregated. did. As in the second embodiment, this makes it possible to increase the frequency of setting the backhaul, facilitate scheduling in the access link at the relay station RN, and maintain high access link efficiency at a high level. Is possible.

(4) Fourth Embodiment Hereinafter, a backhaul setting method according to a fourth embodiment will be described.
In the first to third embodiments, the backhaul setting method based on the premise of maintaining backward compatibility with LTE regarding the HARQ return timing has been described. That is, in the first to third embodiments, it is assumed that an ACK / NACK signal (A / N) is returned 4 ms after data transmission (data). However, if backward compatibility with LTE is not assumed, the access link efficiency can be increased by a method different from the method described in the first to third embodiments.

  In the present embodiment, unlike LTE regulations, it is assumed that an ACK / NACK signal is returned 4 ms after downlink data transmission and an ACK / NACK signal is returned 6 ms after uplink data transmission. If this premise is followed, as illustrated in FIG. 5, the positions of the downlink backhaul and the uplink backhaul can be always constant in each frame. Although FIG. 5 shows an example in which the downlink backhaul is set to the subframe # 1, the present invention is not limited to this. As long as the uplink backhaul is set 4 ms after the downlink backhaul, the downlink backhaul can be set at an arbitrary position in one frame.

  As shown in FIG. 5, when downlink backhaul is set to subframe # 1, HARQ cannot be executed at some timing of each HARQ process of process numbers PID2, PID4, PID6, and PID8. As already mentioned. In the present embodiment, a section in which this HARQ cannot be executed is set to a measurement gap defined by LTE.

  As described in Non-Patent Document 3, the measurement gap is a section of 6 ms for downlink and 7 ms for uplink provided for handover of the mobile station UE. For example, 40 ms is defined as the measurement gap interval. In this measurement gap, the mobile station UE switches the reception frequency and performs radio quality measurement in a frequency band different from the frequency band of the relay station RN that is currently communicating. That is, since uplink transmission from the mobile station UE to the relay station RN is performed in the measurement gap, there is no problem even if HARQ cannot be executed in the measurement gap.

  FIG. 12 is a diagram showing a measurement gap section when a backhaul is set at the timing shown in FIG. FIG. 12 differs from FIG. 5 in that a section of (f) Measurement gap is added. In FIG. 12F, as an example, a measurement gap section of the mobile stations UE1 to UE4 is shown.

  Each mobile station UE connected to the relay station RN is assigned to one of the HARQ processes with process numbers PID1 to PID8. Therefore, in the present embodiment, for a mobile station UE assigned to a HARQ process including an HARQ section that cannot be executed, the section including the HARQ that cannot be executed is set as a measurement gap section. For example, in the example illustrated in FIG. 12, it is assumed that the mobile station UE1 is assigned to the process number PID6. At this time, a measurement gap section including a section of subframes # 5 to # 9 of frame Frame_0 is set for mobile station UE1. In the example shown in FIG. 12, mobile stations UE2, UE3 and UE4 are assigned to process numbers PID8, PID2 and PID4, respectively, and a measurement gap section is set in the same manner.

  In the backhaul setting method of the present embodiment, the setting of the backhaul itself is performed by the same method as in the first to third embodiments described above. In the present embodiment, a measurement gap section including a HARQ section that cannot be executed is set for the mobile station UE. That is, since each mobile station UE sets a measurement gap in a section where the access link cannot be used, it is possible to maintain the efficiency of the access link while ensuring a large backhaul setting frequency.

  Note that the setting of the backhaul shown in FIG. 12 is merely an example for explaining the present embodiment. The measurement gap section including the non-executable HARQ section may be set for the mobile station UE allocated to the HARQ process including the non-executable HARQ, and the position of the backhaul in one frame is not limited. . Therefore, it is clear that the setting of the measurement gap section of this embodiment can be applied to the first to third embodiments described above. That is, the present invention can also be applied to the case where the LTE ACK / NACK signal reply timing is maintained. For example, in the case of the backhaul setting method shown in FIG. 8A, the measurement gap section including the section from the subframe # 4 of the frame Frame_0 to the subframe # 6 of the frame Frame_1 (the section in which HARQ cannot be executed) This is set for the mobile station UE assigned to the process number PID5.

(5) Fifth Embodiment Hereinafter, a relay station and a mobile station according to a fifth embodiment will be described.
In the present embodiment, configurations and operations of the relay station and the mobile station for executing the processes of the first to fourth embodiments described above will be described.

(5-1) Configuration of Relay Station FIG. 13 is a block diagram showing a schematic configuration of the relay station.
As illustrated in FIG. 13, the relay station RN of the present embodiment relays wireless communication between the base station eNB and the mobile station UE. The relay station RN includes transmission / reception units 31 and 32, a Uu HARQ unit 35, an Un HARQ unit 36, and a control unit 40. The control unit 40 includes a backhaul management unit 45, an access link management unit 46, and a HARQ management unit 47.

  The transmission / reception unit 31 (first transmission / reception unit) performs transmission / reception processing with the mobile station UE. The transmission / reception unit 32 (second transmission / reception unit) performs transmission / reception processing with the base station eNB. This relay station RN demodulates and decodes the received signal once when relaying wireless communication between the base station eNB and the mobile station UE. Then, the demodulated and decoded data signal in the received signal is subjected to scheduling and then encoded and modulated again and transmitted. For example, when the downlink signal is OFDM, the transmission / reception unit 32 separates the data signal in units of subcarriers by performing FFT processing on the OFDM signal received from the base station eNB, and performs demodulation and decoding processing on the data signal. Do. The data signal is encoded and modulated again, and is mapped to a predetermined radio frame format by the scheduler 33. The transmission / reception unit 31 performs conversion to time domain signals (IFFT processing) for each subcarrier, time domain signal synthesis processing, CP (Cyclic Prefix) addition processing, and the like.

  The Uu HARQ unit 35 executes HARQ for data transmission / reception with the mobile station UE. HARQ processing is already known and will not be described in detail here. For example, the Uu HARQ unit 35 generates a data block obtained by performing error correction coding on information bits when transmitting data addressed to the mobile station UE. Then, if the data block is not correctly received by the mobile station UE (when the transmission / reception unit 31 receives a NACK signal), the Uu HARQ unit 35 generates another data created based on the same information bits. Processing such as generating a block is performed. These data blocks are transmitted from the transmission / reception unit 31. Further, the Uu HARQ unit 35 generates an ACK / NACK signal, which is a data confirmation response from the mobile station UE, addressed to the mobile station UE. This ACK / NACK signal is transmitted from the transmission / reception unit 31.

Similar to the Uu HARQ unit 35, the Un HARQ unit 36 executes HARQ with respect to data transmission / reception with the base station eNB.
The transmission / reception unit 32 of the relay station RN receives a backhaul setting message in which configuration data (see FIGS. 9 and 11) related to backhaul setting is described from the base station eNB. And the backhaul management part 45 of the control part 40 sets and manages the backhaul between base stations eNB based on the data of the configuration contained in the backhaul setting message. Note that the backhaul setting message is transferred to the mobile station UE to which the relay station RN is connected.

  The access link management unit 46 of the control unit 40 refers to the backhaul section set by the backhaul management unit 45 and sets the downlink backhaul in the MBSFN subframe. Further, the access link management unit 46 permits uplink data transmission (in PDCCH) 4 ms before the uplink backhaul so that the mobile station UE does not perform uplink data transmission on the uplink backhaul set by the backhaul management unit 45. Manage not to give (UL grant) to be sent.

  The access link manager 46 serving as the first measurement section manager is a mobile station assigned to the HARQ process, which includes a measurement gap calculated by the HARQ manager 47 and including a section in which HARQ cannot be executed in a specific HARQ process. Can be set to UE. Note that the access link management unit 46 generates a measurement gap setting message in which information about the section of the measurement gap is described as a message addressed to the mobile station UE.

  The HARQ management unit 47 as the first communication management unit manages the HARQ process in TTI units of subframes. The HARQ management unit 47 assigns HARQ processes with process numbers PID1 to PID8 for each connected mobile station UE. Furthermore, the HARQ management unit 47 calculates a HARQ process that is not used in the access link with the mobile station UE and a section in which HARQ cannot be executed in the HARQ process, based on the backhaul setting message received from the base station eNB.

(5-2) Configuration of Mobile Station FIG. 14 is a block diagram showing a schematic configuration of the mobile station.
As shown in FIG. 14, the mobile station UE of this embodiment performs transmission / reception of radio communication with the relay station RN. The mobile station UE includes a transmission / reception unit 61 and a control unit 70. The control unit 70 includes a Uu HARQ management unit 75 (second communication management unit) and a measurement gap management unit 76 (second measurement section management unit).

The transmission / reception unit 61 performs transmission / reception processing with the relay station RN or the base station eNB. Note that the transmission / reception processing of the transmission / reception unit 61 is the same as the processing of the relay station RN.
Based on the configuration data received from the relay station RN through the transmission / reception unit 61, the Uu HARQ management unit 75 calculates the HARQ section that cannot be executed among the HARQ processes assigned to the own station, To manage the communication timing of access links. The measurement gap management unit 76 sets (assigns) a measurement gap section according to the section described in the measurement gap setting message received from the relay station RN. The measurement gap management unit 76 further performs a process of measuring a signal in a frequency band different from the frequency band of the relay station RN that is currently communicating by switching the reception frequency in this section.

(5-3) Operation of Relay Station RN Next, an example of operation of the relay station RN mainly related to backhaul setting will be described with reference to FIGS. 15 and 16. 15 and 16 are flowcharts showing an example of the operation of the relay station RN. The flowchart of FIG. 15 shows the operation of the relay station RN corresponding to the second and third embodiments, and the flowchart of FIG. 16 shows the operation of the relay station RN of the fourth embodiment.

  First, referring to FIG. 15, the transmission / reception unit 32 of the relay station RN receives a backhaul setting message from the base station eNB (step S10). The backhaul management unit 45 acquires configuration data (Configuration; see FIGS. 9 and 11) described in the backhaul setting message (step S12). The backhaul management unit 45 sets a downlink backhaul and an uplink backhaul in each frame according to the value of SFN mod 4 based on the acquired configuration data. Next, the access link management unit 46 sets a downlink subframe (DL subframe) corresponding to the configuration data (eg, FIG. 9A) acquired in step S12, that is, an MBSFN subframe (MBSFN subframe) ( Step S14). Further, the access link management unit 46 sets the uplink backhaul according to the configuration data (for example, FIG. 9B) acquired in step S12, and the mobile station UE 4ms before the uplink backhaul. The transmission control signal (UL grant transmitted by PDCCH) is not given (step S16). The HARQ management unit 47 calculates a HARQ process that is not used in the access link with the mobile station UE based on the configuration data acquired in step S12 (step S18).

  Next, referring to FIG. 16, steps S30 and S32 are added to the flowchart of FIG. In step S30, the access link management unit 46 sets a measurement gap including a section in which HARQ cannot be executed in a specific HARQ process for the mobile station UE assigned to the HARQ process (step S30). Then, the transmission / reception unit 31 transmits a measurement gap setting message including information on the measurement gap section set in step S30 to the corresponding mobile station UE (step S32).

(5-4) Operation of Mobile Station Next, an example of operation of the mobile station UE will be described with reference to FIG. 17 and FIG. FIG.17 and FIG.18 is a flowchart which shows an example of operation | movement of the mobile station UE. The flowchart of FIG. 17 shows the operation of the mobile station UE corresponding to the second and third embodiments, and the flowchart of FIG. 18 shows the operation of the mobile station UE of the fourth embodiment.

  First, referring to FIG. 17, the transmission / reception unit 61 of the mobile station UE receives a backhaul setting message transmitted from the relay station RN (step S20). The Uu HARQ management unit 75 of the control unit 70 acquires configuration data described in the backhaul setting message acquired in step S20 (step S22). The Uu HARQ management unit 75 further calculates a non-executable HARQ section among the HARQ processes assigned to the own station based on the configuration data acquired in step S22 (step S24).

  Next, referring to FIG. 18, steps S40 to S44 are added to the flowchart of FIG. The transmitter / receiver 61 of the mobile station UE receives the measurement gap setting message (step S40). The measurement gap management unit 76 sets the measurement gap section described in the measurement gap setting message received in step S40 (step S42). In this measurement gap section, the mobile station UE measures a signal in a frequency band different from the frequency band of the relay station RN that is currently communicating. Furthermore, the measurement gap management unit 76 includes the downlink and uplink backhaul based on the configuration data described in the backhaul setting message acquired in step S20 in the measurement gap section set in step S42. Confirm (step S44).

  As mentioned above, although the embodiment of the present invention has been described in detail, the communication section setting method, the relay station, the mobile station, and the mobile communication system of the present invention are not limited to the above-described embodiment, and in a range not departing from the gist of the present invention. Of course, various improvements and changes may be made.

RN ... Relay station 31, 32 ... Transmission / reception unit 35 ... Uu HARQ unit 36 ... Un HARQ unit 40 ... Control unit 45 ... Backhaul management unit 46 ... Access link management unit 47 ... HARQ management unit UE ... Mobile station 61 ... Transmission / reception unit 70 ... Control part 75 ... Uu HARQ management part 76 ... Measurement gap management part

Claims (6)

A communication section setting method in a mobile communication system including a relay station that relays wireless communication between a base station and a mobile station,
In the section where the transmission subframe from the relay station to the mobile station becomes the MBSFN subframe, the downlink communication section in which the relay station receives the transmission signal from the base station, and the transmission of the signal from the mobile station to the relay station are restricted By setting at least one communication section of the uplink communication section for transmitting a transmission signal to the base station by the relay station,
On the access link between the mobile station and the relay station, a plurality of communication processes for managing communication processing including data transmission and confirmation response after the data transmission are provided,
The uplink communication section is set at a timing according to the timing of uplink data transmission of the specific communication process so that the communication process of the plurality of communication processes is not limited to a specific communication process. Can be set,
A downlink communication section is set after a predetermined time of each set uplink communication section;
Communication section setting method. Allocating a section in which the communication processing cannot be performed among the plurality of communication processes to a measurement period for measurement by a mobile station of a radio signal having a frequency different from a communication frequency between the relay station and the mobile station, In addition,
The communication section setting method according to claim 1. At least a part of the configured uplink communication section includes allocating to transmission of uplink data that does not require an acknowledgment from the base station,
The communication section setting method according to claim 1 or 2. A relay station that relays wireless communication between a base station and a mobile station,
A first transceiver for transmitting and receiving signals to and from the base station;
A second transmitter / receiver for transmitting / receiving signals to / from a mobile station;
The second transmitter / receiver sets the subframe to the mobile station as an MBSFN subframe, so that the first transmitter / receiver receives the transmission signal from the base station, and the mobile station transmits the signal to the relay station. A controller configured to set at least one communication section of the uplink communication section in which the first transmitter / receiver transmits a transmission signal to the base station by limiting,
A communication management unit for managing a plurality of communication processes for executing communication processing including data transmission and an acknowledgment after the data transmission on the access link between the mobile station and the relay station;
With
The control unit, at a timing according to the timing of uplink data transmission of the specific communication process, is limited to a specific communication process having a communication process that cannot execute the communication process among the plurality of communication processes. The uplink communication section can be set, and after a predetermined time of each set uplink communication section, a downlink communication section is set.
Relay station. A mobile station that performs radio communication with a base station via a relay station,
A transmission / reception unit for transmitting / receiving radio signals to / from the relay station;
In the section where the transmission subframe from the relay station to the mobile station becomes the MBSFN subframe, the downlink communication section in which the relay station receives the transmission signal from the base station, and the transmission of the signal from the mobile station to the relay station are restricted A communication management unit that manages communication timing with the relay station based on at least one of the communication sections of the uplink communication section that transmits a transmission signal to the base station at the relay station,
With
The communication section is a communication process in which communication processing cannot be executed among a plurality of communication processes that execute communication processing including data transmission and an acknowledgment after the data transmission on the access link between the mobile station and the relay station. Set to be limited to a certain communication process,
Mobile station. In a mobile communication system including a relay station that relays wireless communication between a base station and a mobile station,
The base station, in a section in which the transmission subframe from the relay station to the mobile station is an MBSFN subframe, a downlink communication section in which the relay station receives a transmission signal from the base station, and signal transmission from the mobile station to the relay station By setting at least one communication section of the uplink communication section that transmits a transmission signal to the base station at the relay station by restricting,
The relay station is provided with a plurality of communication processes for managing communication processing consisting of data transmission and an acknowledgment after the data transmission on the access link between the mobile station and the relay station,
The uplink communication section is set at a timing according to the timing of uplink data transmission of the specific communication process so that the communication process of the plurality of communication processes is not limited to a specific communication process. Can be set,
The mobile station sets a downlink communication section after a predetermined time of each set uplink communication section.

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