JP4675825B2 - Data transfer method - Google Patents

Description

  The present invention relates to a data transfer method when a base station and a radio terminal transmit and receive data via a repeater, and in particular, the repeater is obtained by aggregating a plurality of received data (frames). The present invention relates to a data transfer method for transmitting a received frame to a destination base station or wireless terminal.

  In the third-generation mobile phone system that is currently popular, voice communication is not IP, but in the future, it is predicted that all communication including voice will also be IP. For example, in the following Non-Patent Document 1, which is a US wireless standard, standardization regarding such IP broadbandization in mobile communication is performed.

  FIG. 21 is a diagram illustrating an example of a network (wireless communication system) configuration defined in Non-Patent Document 1 below. This network includes a base station (hereinafter referred to as BS), a plurality of It is composed of a wireless terminal (Mobile Station, hereinafter referred to as MS). Hereinafter, a conventional wireless communication system will be described with reference to FIG.

  In FIG. 21, two types of ellipses are drawn with the BS as the center and the communication range with the BS. The inner ellipse indicates an area where the propagation environment from the BS is good, and the outer ellipse indicates an area where the propagation environment from the BS is bad. The outside of the ellipse indicates an area where communication with the BS is impossible. For convenience, the communication area with the BS is classified into three stages, but the propagation environment is determined by physical characteristics such as distance attenuation, fading, multipath, carrier frequency, etc. in the propagation path. . In addition, the back of the building shows a situation where communication is not possible due to shadowing. In the following Non-Patent Document 1, a modulation / demodulation method using OFDM (Orthogonal Frequency Division Multiplexing) using OFDM, an OFDMA (Orthogonal Frequency Division Multiple Access), a method using a single carrier, and the like are defined.

  Next, a plurality of wireless terminals (MS) in the communication area will be described. Each MS belongs to one of “area with good propagation environment”, “area with bad propagation environment”, and “area where communication is impossible” classified for convenience in the above description. Here, in a normal communication system, each terminal (equivalent to BS, MS, etc.) that performs communication needs to satisfy the prescribed communication quality regardless of the propagation environment. As the communication quality, for example, a packet error rate (hereinafter referred to as PER) is used.

  Therefore, in the example shown in FIG. 21, MSs # 1 and # 2 belonging to an area with a good propagation environment can communicate with the BS using a highly efficient transmission rate. On the other hand, the MSs # 3 to # 5 belonging to an area where the propagation environment is bad communicate with the BS using a low-efficient transmission rate in order to satisfy the specified communication quality, or data with a short packet length. Need to communicate with BS. Since MS # 6 to MS # 9 belong to an area where communication with the BS is impossible, the signals from the BS cannot be received.

  Therefore, when data of the same size is communicated between the BS and the MS, in order to satisfy the same PER, in an area where the propagation environment is poor, a modulation scheme or coding which is less efficient than an area where the propagation environment is good The rate is used (see FIG. 22). As a result, the system throughput of the cell decreases due to the influence of terminals belonging to areas where the propagation environment is bad.

  Here, a conventional technique for solving the problem that the throughput is lowered due to an influence on a terminal belonging to an area having a poor propagation environment will be described with reference to FIG. FIG. 23 shows a relay station (hereinafter referred to as “RS”) arranged in the wireless communication system shown in FIG. 21 to expand the communication area (Cell Expansion) and complement the communication area (reduce cell hole). 1 shows a configuration example of a realized wireless communication system. Specifically, a wireless communication system in which RS # 1 is arranged on a building for expansion of a communication area, and RS # 2 to RS # 4 are installed to complement outside the communication area / communication area is shown. ing. Communication between BS and RS may be caused by interference due to multipaths from other buildings or degradation of propagation quality due to distance attenuation. However, by using a directional antenna, high transmission power, etc. It is assumed that the communication is performed in a better state than the communication between the BS and the MS. In addition, after RS installation, MS # 3-MS # 9 will communicate via RS.

  By arranging the repeater as shown in FIG. 23, the MS # exists at the cell edge or the like and is inefficient in the wireless communication system (wireless communication system in which no repeater is shown) shown in FIG. 3-MS # 6 has a better propagation environment for repeaters. Therefore, it becomes possible to use a more efficient modulation scheme or coding rate, and the system throughput is improved (see FIG. 24). Further, the MS can communicate with the RS with less transmission power than when communicating with the BS.

IEEE Std 802.26-2004, October 2004

  Next, problems of the conventional technique using the above-described repeater will be described. FIG. 25 is a diagram illustrating an example of a wireless communication system to which the related art is applied. This wireless communication system includes a base station (BS), a repeater (RS), and MSs (MS # 1, MS # 2, MS # 3, MS # 4, ...) connected to the RS and communicating with the BS. MS # n). In describing the effect of the RS shown in FIG. 23, one RS and a wireless terminal connected thereto are shown for convenience, but the present invention is not limited to this mode.

  The RS and each MS communicate with the BS by setting a connection identifier (hereinafter referred to as CID) for communicating with the BS. Here, the CID is mapped to the BS, RS, and MS addresses, and it is possible to determine whether or not the frame is addressed to the own terminal. Further, this CID can be set for each application, uplink, downlink, etc., and one MS can have a plurality of CIDs. FIG. 25 shows an example in which each MS has three CIDs. For example, MS # 1 has a connection of CID # 11, CID # 12, and CID # 13 with a BS. Is shown.

  As an example, when communication is performed between the BS and the MS # 1, the CID # 11 to CID # 13 determined by the BS and the MS # 1 are used. FIG. 25 shows a state where communication is performed using CID # 11. Specifically, MS # 1 transmits data to RS, and RS receives data from MS # 1. It shows a state where the transferred data is transferred to the BS.

  In this description, the RS terminates the protocol with PHY / MAC and the RS simply transfers the MS data (see FIG. 26). However, the RS terminates the protocol with PHY. The termination is not limited to the MAC layer, the IP layer, and the TCP / UDP layer. In that case, it is also possible to newly set the CID for the data of the CID from the MS (for example, CID # 11 from the MS # 1) between the BS and the RS, and replace the header for transmission. (See FIG. 27). It is also possible to encapsulate data (packets) received from the MS, further transfer with a new CID.

  However, even if the RS performs any of the transfer methods described above, the data between the BS and the RS and the data between the MS and the RS have a one-to-one correspondence. When a lot of MSs are connected, there is a problem that the traffic between the BS and the RS is consumed.

  Here, IEEE 802.11n, which is one of the standards for wireless LANs, proposes a frame aggregation method (frame aggregation method) that bundles and transmits a plurality of short packets to achieve high efficiency. This is a technique for improving efficiency by combining a plurality of frames (aggregating a plurality of frames) and generating and transmitting a new frame. IEEE802.11n assumes a wireless communication system configured with a base station (referred to as Access Point (AP) in IEEE802.11n) and a wireless terminal (referred to as Station (STA) in IEEE802.11n) (see FIG. 28), communication via a repeater as described above is not considered (communication via a repeater is not defined). In a wireless communication system to which IEEE 802.11n is applied, a base station manages each wireless terminal. Basically, each base station and a terminal are identified using a unique MAC address. Yes. Further, CSMA / CA is used as an access method, which is basically different from the method studied in Non-Patent Document 1.

  Various studies have been made on the frame aggregation method, and representative examples include an MSDU aggregation method, an MPDU aggregation method, and a RIFS bursting method.

  The MSDU aggregation method mainly concatenates a plurality of MSDUs (MAC Service Data Units) having the same destination address, a MAC header (MAC Header) for the concatenated data, and an FCS (Frame Check Sequence) for determining success or failure of reception. ) Is added to the frame format, and is also used in the IEEE802.11n MAC layer. Although this method is simple and highly efficient, there is a problem that the packet length cannot be increased in a situation where the propagation environment is bad because only one FCS is attached to the entire frame.

  In addition, the MPDU aggregation method has a frame format in which a MAC header and a plurality of MPDUs (MAC Protocol Data Units) composed of Data and FCS are concatenated, and a Delimiter (delimiter) is inserted between each MPDU to indicate the head of the MPDU It is a method that is also used in the MAC layer of IEEE 802.11n. In this method, since FCS is added to each data, even if an error occurs in the data before and after concatenation, reception is successful for packets that are judged to be normal. Therefore, it is highly robust. On the other hand, since the MAC header and FCS are connected to each Data, there is a disadvantage that it is inefficient compared to the MSDU aggregation method.

  In addition, the RIFS Bursting scheme features a frame sequence in which a frame including a preamble for PHY synchronization, a data field for demodulation, and a PSDU (PHY Service Data Unit) is continuously transmitted in a short time interval (RIFS: Reduced Interframe Space). This method is also used in the IEEE 802.11n PHY layer. This method is simple and highly robust because the modulation degree of each packet can be changed. On the other hand, each frame has a disadvantage that it is inefficient compared to the MSDU aggregation method and the MPDU aggregation method because a preamble, a data field for demodulation, a MAC header, FCS, and the like are added to Data. is doing.

  However, in any of the above-described frame aggregation schemes, a newly generated frame is transmitted to the MAC address that is physically determined by the MS, so the frames are naturally bundled for each MAC address. Therefore, instead of concatenating frames according to a specific application or QoS, the main purpose is to concatenate frames for a specific MAC address or a plurality of specific MAC addresses. Further, for a plurality of destination MAC addresses, frame aggregation can be applied to packets for the downlink, but there is a problem that it cannot be applied to packets for the uplink.

  Also, as described above, it is assumed that frame aggregation is applied to downlink packets transmitted directly from the BS to the MS, and cannot be applied to downlink packets from the BS to the RS. There was a problem. That is, a method of applying the above-described frame aggregation scheme to communication between BS and RS is not disclosed, and there is a problem that the existing frame aggregation scheme cannot be applied as it is.

  The present invention has been made in view of the above, and enables frame aggregation to be applied to communication between a base station (BS) and a repeater (RS), thereby realizing high efficiency of data transfer. The purpose is to obtain a data transfer method.

  It is another object of the present invention to provide a data transfer method capable of applying frame aggregation to uplink communication (transmission from MS to BS, transmission from MS to RS, and transmission from RS to BS).

  In order to solve the above-mentioned problems and achieve the object, the present invention provides a relay communication apparatus that constitutes a wireless communication system that receives a data sequence received from one or more specific transmission source communication apparatuses for a destination communication apparatus. In the case of receiving an aggregation frame that includes only a single data frame or a data sequence of the same destination, it is included in the received frame within a specific time after receiving the frame. In the same destination data sequence receiving step of receiving another frame (single data frame or aggregation frame) including only the data sequence of the same destination as the destination of the data sequence, and in the same destination data sequence receiving step, a single data frame And / or received multiple aggregation frames Based on all the data series included in the frame and the transmission source information of each data series and the destination information indicating the destination of each data series, the multiple data series and the destination information associated with each are included. An aggregation frame generating step for generating an aggregation frame.

  According to the present invention, it is possible to perform aggregation between frames with different transmission sources, which cannot be aggregated by the conventional method. Therefore, it is possible to improve efficiency of data transfer and improve system throughput. Play.

  Embodiments of a data transfer method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a first embodiment of a wireless communication system to which a data transfer method according to the present invention is applied. This wireless communication system includes a base station (BS) 10, a repeater (RS) 20, and wireless terminals (MS) 30 to 33. The BS 10 is connected to the backbone network by wired or the like, and communicates with the subordinate RS 20 and the MS 30. Further, the RS 20 is arranged for coverage expansion of the BS 10, improvement of throughput at the cell edge, reduction of communication area / out-of-service area (reducing coverage holes), and the like. Here, RS20 has accommodated MS31-33. Further, the MSs 31 to 33 are in a state in which direct communication with the BS 10 is not possible. And MS31-33 performs communication with BS10 and a backbone network via RS20.

  Also, the CID added to each of the BS 10, RS 20, and MSs 30 to 33 or the number starting from the RS-CID indicates an example of a connection identifier (CID) handled by each terminal. In the present embodiment, it is assumed that the BS 10 manages all RS-CIDs and CIDs. In the following description, it is assumed that the BS 10 and the RS 20 recognize how the MSs 30 to 33 are connected to the wireless communication system. Regarding this recognition, it is assumed that the MS transmits a connection request to the BS or RS and recognizes it through the process of Authentication and Association. For convenience, the description will be made assuming that only the RS 20 and the MS 30 are connected to the BS 10, but the configuration of the radio communication system is not limited to this, and the radio communication has a configuration in which a plurality of RSs and MSs are connected to the BS 10. The present invention can also be applied to a system.

  FIG. 2 is a diagram illustrating a configuration example of a frame aggregation frame (a frame after bundling frames corresponding to a plurality of CIDs, hereinafter referred to as an FA frame) in the present embodiment. This FA frame includes a GM Header (General MAC Header, hereinafter referred to as a GM header), a FA Sub Header (Frame Aggregation Sub Header, hereinafter referred to as an FA sub header), a plurality of Data, and a frame check for the entire FA frame. It consists of CRC (Cyclic Redundancy Check) which is a sequence. Here, the GM header follows IEEE 802.16-2004 and IEEE 802.16e-2005, which are existing wireless standards, HT (Header Type), 1 bit, EC (Encryption Control), 1 bit, Type (type of subheader) ), 6 bits, ESF (Extended Subheader Field), 1 bit, CI (CRC Indicator), 1 bit, EKS (Encryption Key Sequence), 2 bits, Rsv (Reserved), 1 bit, LEN (packet length), 11 bits, CID, 16 bits, HCS (Header Check Sequence), 8 bits are included.

  In the FA frame of the present embodiment, Rsv (1 bit), which is a reserved area included in the GM header, is newly defined as FAI (Frame Aggregation Subheader Indicator), and this FAI is used behind the GM header. Indicates whether an FA subheader is added. Further, when information indicating that the FA subheader is added to the FAI (when the FAI is “1”), the field assigned as the conventional CID is set between the BS and the RS. Is used as a field indicating an RS-CID which is a CID used in the above (set RS-CID for a conventional CID field).

  FIG. 3 is a diagram illustrating a configuration example of the FA subheader of the FA frame used in the present embodiment. This FA subheader indicates the number of packets to be bundled (aggregated), a subheader type (Sub Header Type) field indicating the type of the subheader, a type (Type) field for notifying the method and type of FA. And a common field including a number field and an extension field for each CID to be aggregated. The extension field includes an FC (Fragmentation Control) field indicating a fragmentation state, a CID field indicating an aggregated CID, an LEN (Length) field indicating the length of the aggregated data, and the like. In the FA frame having the configuration shown in FIG. 2, the data corresponding to CID # 311, CID # 312 and CID # 321 is aggregated, and therefore the extension field is repeated three times in this FA frame.

  Next, the relationship between the RS-CID used between the BS and the RS and the CID used between the MS and the BS (or RS) will be described. FIG. 4 is a diagram illustrating an example of a lookup table used in the BS 10 and the RS 20. In this embodiment, CID # 311, CID # 312 and CID # 321 are associated with RS-CID # 201, and CID # 322 and CID # 331 are associated with RS-CID # 202. It has been. In this embodiment, as shown in FIG. 4, one RS-CID corresponds to one CID. This is because when one CID is assigned to a plurality of RS-CIDs, the RS-CID may not be consistent in the case where the connection created by the BS 10 and the RS 20 is terminated. Because there is. For example, when CID # 332 is associated with both RS-CID # 203 and RS-CID # 204, by interrupting the connection of RS-CID # 203, CID # 332 Part of your traffic may be interrupted.

  Next, an operation in which the BS 10 transmits data to the MSs 31 to 33 will be described. 5 and 6 are diagrams showing an example of a state in which the BS 10 transmits data to the MSs 31 and 32. FIG. In FIG. 5, the BS 10 first includes data associated with the CID # 311, data associated with the CID # 312, and data associated with the CID # 321 with respect to the RS 20. Send the associated data. Specifically, the BS 10 includes a GM header (GMH) including RS-CID # 201, an FA subheader (FA SubH) including each CID (CID # 311, CID # 312, and CID # 321), An FA frame configured by Data is generated and transmitted to the RS 20.

  After receiving the frame transmitted by the BS 10, the RS 20 checks the FA subheader included in the frame, and checks which CID and data related to the CID are included. If CID # 311 is included as a result of the confirmation, RS 20 generates a frame including CID # 311 and data associated therewith and transmits it to MS31. Similarly, if CID # 312 and CID # 321 are included, the data associated with CID # 312 and the data associated with CID # 321 are respectively transmitted to the destination MS.

  Next, an operation in which the MSs 31 to 33 transmit data to the BS 10 will be described. When it is desired to transmit data associated with CID # 311 to the BS 10, the MS 31 transmits CID # 311 and data associated therewith (CID # 311 and a frame including data corresponding thereto) to the RS 20. When receiving the CID # 311 and the data associated therewith, the RS 20 associates them with the RS-CID # 201 (generates an FA frame as shown in FIG. 2). If there are other CIDs and data that need to be associated with RS-CID # 201, these are also associated with RS-CID # 201.

  For example, when the RS 20 receives the CID # 311 and data associated therewith, the RS 20 receives a frame including the CID and data that need to be associated with the RS-CID # 201 within a specified time. When a frame including a CID and data that need to be associated with RS-CID # 201 is received, the CID and data included in the received frame, the received CID # 311 and the associated CID # 311 Associate data with RS-CID # 201. That is, all the data received within the specified time (limited to data that needs to be associated with RS-CID # 201) and an FA frame including the CID are generated.

  Then, the RS 20 transmits the generated FA frame to the BS 10. Note that FIG. 5 shows a state where an FA frame in which data for three CIDs is aggregated is transmitted. However, when there is no traffic for the corresponding CID, as shown in the example shown in FIG. Only data for the CID (CID # 312 and CID # 321 in this example) is aggregated and transmitted.

  Thus, in the present embodiment, a new RS-CID is defined for use in communication between the base station (BS) and the repeater (RS), and a connection using this RS-CID is further defined. And a plurality of conventional wireless terminal connections (base station-wireless terminal connections) are bundled and transmitted (aggregated) in the defined connections. This eliminates the need to transmit a frame for each connection (connection based on the MAC address) established between the base station and each wireless terminal as in the conventional method, and improves the efficiency of the frame sequence, the efficiency of the feedback, and High throughput can be realized.

  In addition, since the propagation environment between the repeater and the wireless terminal becomes better than the propagation environment between the conventional base station and the wireless terminal, a high-efficiency modulation scheme and coding rate can be used even when transmitting data of the same frame length. Can be used, and the packet transmission time is shortened. As a result, delay and jitter can be reduced in communication between the repeater and the wireless terminal.

  In this embodiment, the CID included in the FA subheader is used to manage a plurality of connections (see FIG. 3). Instead of management using the CID, management is performed using a MAC address. Management is performed using a CID (hereinafter referred to as “Compressed CID”) whose number of bits is reduced (compressed) for high efficiency, and management is performed using other connection identifiers / terminal identifiers. , That is good. In this embodiment, the FA subheader is newly defined as a MAC Subheader. However, it can also be assigned to an Extended Sub Header or a MAC signaling header type defined in IEEE 802.16e-2005. Note that a method of assigning the FA subheader to the Extended Sub Header will be described in the following embodiments.

  Further, the Rsv (1 bit) area in the GM header is newly defined as FAI, and this FAI is used to indicate whether or not the FA subheader is added after the GM header. . For example, the FA subheader may be directly detected using SubHeader Type or the like without using FAI.

  In order to avoid errors in the FA subheader, a parity bit or CRC may be added to the header. Furthermore, a FA frame having a configuration in which a unique delimiter (Delimiter) is added may be used so that the receiving terminal can automatically detect the head of the FA subheader or the Data field.

  Furthermore, a CRC may be individually added to the Data field. In this case, even if an error occurs in a part of the FA frame including a specific Data and a CRC for the Data, the head part of the next Data in which an error has occurred in the delimiter added to the head of each Data Can be detected. Therefore, no error occurs in all the aggregated frames, and only the data in which an error has occurred can be retransmitted, thereby improving efficiency. In addition, when CRC is individually added to the Data field, the CRC for the entire frame (the CRC included at the end of the FA frame in FIG. 2) may be ignored, or the CRC itself is deleted. The FA frame may be used.

  Further, in the present embodiment, the present invention is applied to a radio communication system having a configuration as shown in FIG. 1 (a configuration in which RS 20 is connected to BS 10 and MSs 31 to 33 communicate with BS 10 via RS 20). The operation of the present invention has been described. However, the present invention is not limited to this, and the present invention can also be applied to a wireless communication system having a configuration as shown in FIG. In that case, the above-mentioned frame aggregation is applied to the RS 21 and 22 and the MS 34 and 35 traffic connected to the RS 20. That is, BS 10 and RS 20 communicate using FA frames generated based on RS 21 and 22 and MS 34 and 35 traffic. Furthermore, communication between RS20 and RS21 is performed using FA frames generated based on the traffic of MSs 31 to 33 connected to RS21.

Embodiment 2. FIG.
Next, the data transfer method according to the second embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. In the present embodiment, only the parts different from the first embodiment will be described.

  FIG. 8 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the second embodiment. This FA frame differs from the FA frame used in Embodiment 1 (see FIG. 2) only in that an FA subheader is inserted in front of Data corresponding to each CID. Also in this embodiment, the GM header of the FA frame shown in FIG. 8 follows IEEE 802.16-2004 and IEEE 802.16e-2005, which are existing wireless standards.

  FIG. 9 is a diagram illustrating a configuration example of the FA subheader of the FA frame used in the second embodiment. This FA subheader is different from the FA subheader used in Embodiment 1 (see FIG. 3) in that the extension fields (corresponding to FC, CID, LEN, and Other fields) are not repeated in the FA subheader. .

  As described above, in the present embodiment, the RS communicates with the upper BS (or RS) using the FA frame having the configuration shown in FIGS. 8 and 9. Thereby, the effect similar to Embodiment 1 mentioned above can be acquired.

  As described in the first embodiment, not only a method of managing a plurality of connections using a CID but also a MAC address or the like may be used for management. Moreover, it is good also as a FA frame of the structure which added CRC to FA subheader or Data field as needed.

Embodiment 3 FIG.
Next, the data transfer method according to the third embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the second embodiment described above. In the present embodiment, only the parts different from the second embodiment will be described.

  FIG. 10 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the third embodiment. In this FA frame, instead of the GM header of the FA frame (see FIG. 8) of Embodiment 2 and the subsequent FA subheader, a newly defined MMR Header (Mobile Multiple Relay Header, hereinafter referred to as MMR header) is used. Prepare. In this MMR header, FAI (1 bit) of the GM header of Embodiment 2 is set to 1, and 1st CID FC, 1st CID Num, 1st LEN, and 1st CID indicating information on the first CID are added. Other parts are the same as those in the second embodiment.

  Thus, in this embodiment, data transfer is performed using an FA frame having a newly defined MMR header instead of the GM header and the subsequent FA subheader. As a result, the frame size can be reduced as compared with the second embodiment, and data can be transferred more efficiently.

  As described in the first embodiment, not only a method of managing a plurality of connections using a CID but also a MAC address or the like may be used for management. Moreover, it is good also as a FA frame of the structure which added CRC to FA subheader or Data field as needed.

Embodiment 4 FIG.
Next, the data transfer method according to the fourth embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. In the present embodiment, only the parts different from the first embodiment will be described.

  FIG. 11 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the fourth embodiment. This FA frame includes a newly defined MMR header in place of the GM header of the FA frame (see FIG. 2) of Embodiment 1 and the subsequent FA subheader. The MMR header of the present embodiment is obtained by setting the FAI (1 bit) of the GM header of the first embodiment to 1, and further adding information groups (CID FC, CID Num, LEN, CID) for each CID. Other parts are the same as those in the first embodiment.

  Thus, in this embodiment, data transfer is performed using an FA frame having a newly defined MMR header instead of the GM header and the subsequent FA subheader. As a result, the frame size can be reduced as compared with the case of Embodiment 1, and data can be transferred more efficiently.

  As described in the first embodiment, not only a method of managing a plurality of connections using a CID but also a MAC address or the like may be used for management. Moreover, it is good also as a FA frame of the structure which added CRC to FA subheader or Data field as needed.

Embodiment 5. FIG.
Next, the data transfer method according to the fifth embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. In the present embodiment, only the parts different from the first embodiment will be described.

  FIG. 12 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the fifth embodiment. FIG. 13 is a diagram illustrating a configuration example of the FA subheader of the FA frame used in the fifth embodiment.

  In the first to fourth embodiments described above, since it is assumed that an FA frame is generated by aggregating frames including Data fields having different lengths, the data length of each Data field is inserted into the FA frame. It was. Note that such a method (aggregation type) for aggregating frames including Data fields having different lengths is defined as an explicit scheme (Explicit Frame Aggregation for Different Multi CIDs).

  In contrast, in the present embodiment, it is assumed that an FA frame is generated by aggregating frames including a Data field having the same length. Therefore, as shown in FIGS. 12 and 13, the FA frame of the present embodiment includes one basic data length as Basic Length, and omits the individual LEN fields for each Data field. Other parts are the same as those of the FA frame of the first embodiment. Such a method of aggregating frames including Data fields having the same length is defined as an Implicit Frame Aggregation for Different Multi CIDs.

  In the above description, the case where the frames including the same length Data field are aggregated based on the FA frame of the first embodiment has been described. However, based on the FA frame of the third and fourth embodiments. It is also possible to do.

  As described above, in the present embodiment, when data having the same length (Data field) are aggregated, an FA frame including only common data length information is generated. Thereby, compared with the case where the FA frame having the configuration of the first to fourth embodiments described above is used, a smaller-sized FA frame can be generated, and higher efficiency can be realized.

  As described in the first embodiment, not only a method of managing a plurality of connections using a CID but also a MAC address or the like may be used for management. Moreover, it is good also as a FA frame of the structure which added CRC to FA subheader or Data field as needed.

Embodiment 6 FIG.
Next, the data transfer method according to the sixth embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. This embodiment is an extension of the first to fifth embodiments. Therefore, in the present embodiment, only those extended portions will be described.

  FIG. 14 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the sixth embodiment. In FIG. 14, the FA frame of Type # 1 is an extension of the FA frame of Embodiment 1 (see FIG. 2). Specifically, a CRC is added to each Data field. In addition, the reliability of the FA subheader can be improved by adding CRC or Parity to the FA subheader. Furthermore, it is possible to add a delimiter consisting of a unique bit pattern for detecting the head position of each Data field. As a result, when an error occurs in the packet, it is possible to identify the Data field in which the error has occurred and the normal Data field. Therefore, it is not necessary to retransmit the entire frame when a packet error occurs, and high efficiency can be realized.

  When the Type # 1 FA frame is used, the CRC result for each Data field can be used, and the CRC result for the entire frame (the CRC added to the end of the frame) can be ignored.

  The FA frame of Type # 2 is an extension of the FA frame of Embodiment 2 (see FIG. 8). More specifically, a CRC is added to each FA subheader and the Data field corresponding thereto (following). It is also possible to add a delimiter consisting of a unique bit pattern for detecting the head position of each FA subheader. As a result, when an error occurs in the packet, it is possible to identify the FA subheader and Data field in which the error has occurred and those that can be normally received in the subsequent FA subheader and Data field. Therefore, it is not necessary to retransmit the entire frame when a packet error occurs, and high efficiency can be realized.

  Note that when using a Type # 2 FA frame, the CRC result for the entire frame can be ignored, as in the case of using a Type # 1 FA frame.

  The FA frames of Type # 3 and # 4 are extensions of the FA frames of Embodiments 3 and 4 (see FIGS. 10 and 11), respectively. The specific extension method is the same as that of Type # 1 and # 2 described above, and is a method in which CRC is added to the Data field or FA subheader and Data field. In addition, a delimiter for enabling identification of a region where an error has occurred and a region where the error has not occurred may be added immediately before the target region of each CRC.

  Types # 5 to # 7 are obtained by extending the FA frame (see FIG. 12) used when the frames including the Data field having the same length as shown in the fifth embodiment are aggregated. Type # 5 is based on the FA frame of the first embodiment, and is an extension of the FA frame used when aggregating frames including the same length Data field. Type # 6 and # 7 are obtained by modifying the FA frame of Type # 5 into a configuration having an MMR header, and improving the efficiency by reducing the size of the header portion. The effect is the same as that of Type # 1 to # 4 described above.

  As described above, in the present embodiment, in the frame aggregation operation, an FA frame having a format in which CRC is added to each Data field is generated. As a result, on the FA frame receiving side, when a packet error occurs, it is possible to determine the error area, and it is possible to reduce the amount of data to be retransmitted and improve efficiency.

  In addition, it is good also as using the FA frame of the format which deleted CRC with respect to the whole flame | frame as shown in FIG. In this case, the frame size is reduced and efficiency can be improved.

Embodiment 7 FIG.
Next, the data transfer method according to the seventh embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. In a conventional GM header (GM header defined by IEEE 802.16-2004 and IEEE 802.16e-2005, which are existing wireless standards), a LEN (Length) field indicating a frame length is 11 bits. For this reason, the conventional data transfer method has a restriction that only FA frames having a maximum packet length of 2048 bytes calculated from 11 bits can be generated. That is, even when the propagation environment between the BS and the RS is good, and even when a highly efficient modulation method and coding method can be used, the frame length can be increased to improve the MAC transmission efficiency. It was impossible due to restrictions.

  For example, when the propagation environment is good, by using a more efficient modulation scheme and coding rate (for example, 64QAM and coding rate = 3/4), even when sending frames of the same length, low A frame can be transmitted in a shorter time than when an efficient modulation scheme and coding rate (for example, BPSK and coding rate = 1/2) are used. Therefore, in the same time, when the propagation environment is good, it is possible to send many frames. To that end, it can be considered to improve the efficiency by extending the frame length to be transmitted at one time. However, due to the limitation of the maximum packet length, the effect of frame aggregation can be obtained effectively. There wasn't. By extending the frame length, the PER increases in the same environment. However, as shown in the sixth embodiment, it is possible to retransmit effectively by adding a CRC to each Data field. It is possible to cope with an increase in PER due to the extension of the packet length.

  Therefore, in this embodiment, a data transfer method that can extend the frame length and improve the transmission efficiency will be described.

  First, as a first method, as shown in FIG. 16, Rsv (1 bit) in the GM header is assigned to the LEN (Length) field (11 bits) as an Extended Length. Thereby, the LEN field can be expanded to 12 bits (= 4096 bytes).

  Next, as a second method, when Rsv in the GM header is used and the area is 1, the LEN field in the FA sub-header is replaced with the existing LEN field (LEN field in the GM header). Used to indicate the frame length of the FA frame. In this case, the sum of the GM header length (fixed value) and the LEN field described in the FA subheader is the frame length. In this way, by using Rsv, it becomes possible to simultaneously notify that the FA subheader is connected later. In the data transfer methods of the first to sixth embodiments described above, an FA frame having a size exceeding 2048 bytes can be obtained. Can be generated. Further, since the data transfer method is the same as that shown in the first to sixth embodiments, the description thereof is omitted.

  As described above, in this embodiment, the LEN field is extended using the Rsv area of the existing GM header so that an FA frame having a data length longer than that of the conventional one can be generated. As a result, it is possible to generate a FA frame having a size larger than that of the conventional one, and to improve transmission efficiency.

Embodiment 8 FIG.
Next, the data transfer method according to the eighth embodiment will be described. The configuration of the wireless communication system of the present embodiment is the same as that of the first embodiment described above. In Embodiments 1 to 7 described above, the FA frame is generated using the newly defined FA subheader or MMR header. Here, in IEEE 802.16e-2005, an extended subheader group (extended subheader group) is defined, but frame aggregation using the extended subheader is not defined at all (an extended subheader used for frame aggregation). Is not specified). Therefore, in this embodiment, a data transfer method performed by generating an FA frame using an extended subheader included in the extended subheader group will be described.

  FIG. 17 and FIG. 18 are diagrams showing the configuration of the extended subheader group defined in IEEE 802.16e-2005. FIG. 19 is a diagram showing a list of extended subheader types (ES Type) defined for use in the downlink (DL), and FIG. 20 is defined for use in the uplink (UL). It is a figure which shows the list of completed extended subheader types.

  From FIG. 19, the extended subheader types 0 to 5 for DL are already defined in IEEE 802.16e-2005. Similarly, from FIG. 20, 0 to 4 extended UL header types are already defined. Therefore, the extended subheader type 6 is used in each of DL and UL as an FA subheader used in the data transfer method according to the present invention. Note that the extended subheader type used to indicate the FA subheader may be other than 6 as long as it is not defined above (6 to 127 for DL and 5 to 127 for UL). Use one of them as it is left).

  Note that the FA subheader actually used in the first to seventh embodiments is assigned to the extended subheader body. For example, in the case of Embodiment 1, the FA subheader having the configuration shown in FIG. 3 is assigned to the extended subheader body as it is. Therefore, the configuration of the FA frame used in the present embodiment is the same as that of the FA subheader and MMR included in the FA frame used in any of Embodiments 1 to 7, except that the extended subheader (the extended subheader type is IEEE 802.16e-). In 2005).

  Further, since the data transfer method is the same as that shown in the first to seventh embodiments, the description thereof is omitted.

  As described above, in the present embodiment, an FA subheader having a format conforming to an existing extended subheader group is defined, and frame aggregation is performed using the FA subheader. As a result, the data transfer method according to the present invention can be easily applied to an existing wireless communication system.

  As described above, the data transfer method according to the present invention is useful for a wireless communication system, and is particularly suitable for a data transfer method used by a repeater installed for the purpose of expanding / complementing a communication area.

It is a figure which shows the structural example of Embodiment 1 of the radio | wireless communications system to which the data transfer method concerning this invention is applied. 6 is a diagram illustrating a configuration example of a frame aggregation frame (FA frame) according to Embodiment 1. FIG. 6 is a diagram illustrating a configuration example of an FA subheader of an FA frame used in Embodiment 1. FIG. It is a figure which shows an example of a lookup table. It is a figure which shows an example of a mode that BS transmits data with respect to MS. It is a figure which shows an example of a mode that BS transmits data with respect to MS. It is a figure which shows the structural example of Embodiment 1 of the radio | wireless communications system to which the data transfer method concerning this invention is applied. FIG. 10 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the second embodiment. 6 is a diagram illustrating a configuration example of an FA subheader of an FA frame used in Embodiment 2. FIG. FIG. 10 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the third embodiment. FIG. 10 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the fourth embodiment. FIG. 10 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the fifth embodiment. FIG. 20 is a diagram illustrating a configuration example of an FA subheader of an FA frame used in the fifth embodiment. FIG. 20 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the sixth embodiment. FIG. 20 is a diagram illustrating a configuration example of an FA frame used in the data transfer method according to the sixth embodiment. FIG. 38 is a diagram illustrating a configuration example of a GM header of an FA frame used in the seventh embodiment. It is a figure which shows the structure of the extended subheader group prescribed | regulated in IEEE802.16e-2005. It is a figure which shows the structure of the extended subheader group prescribed | regulated in IEEE802.16e-2005. It is a figure which shows the list | wrist of the extended subheader type (ES Type) prescribed | regulated for using in a downlink. It is a figure which shows the list | wrist of the extended subheader type (ES Type) prescribed | regulated for using in uplink (UL). It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a subject. It is a figure for demonstrating a subject. It is a figure for demonstrating a subject. It is a figure for demonstrating a subject.

Explanation of symbols

10 Base station (BS)
20, 21, 22 Repeater (RS)
30, 31, 32, 33, 34, 35 Wireless terminal (MS)

Claims (11)

A data transfer method in a case where a relay device configuring a wireless communication system transfers a data sequence received from one or more specific source communication devices to a destination communication device,
When an aggregation frame including only a single data frame or a data sequence of the same destination is received, after receiving the frame, only a data sequence of the same destination as the destination of the data sequence included in the received frame is received within a specific time. other frame including a same destination data series reception step of receiving a single data frame or aggregation frame,
In the same destination data sequence reception step, when a plurality of single data frames and / or aggregation frames are received, all the data sequences included in the received frame and the transmission source information of each data sequence, and each data sequence An aggregation frame generating step for generating an aggregation frame including the plurality of data series and destination information associated with each of the plurality of data series, based on destination information indicating the destination of
Only including,
The aggregation frame is
The unused area in the General MAC Header (GM header) defined in IEEE 802.16-2004 and IEEE 802.16e-2005 is newly defined as FAI (Frame Aggregation Subheader Indicator), and the aggregation frame And a sub-header including data length, destination information, or transmission source information as detailed information about the data series included in the data sequence . Data transfer method according to claim 1, characterized in that the only sub-header that contains detailed information about all of the data sequence included in the aggregation frame, arranged immediately after the GM header. The data transfer according to claim 1 , wherein the subheader is generated for each data sequence included in the aggregation frame, and each subheader is arranged immediately before the data sequence corresponding to the detailed information in each subheader. Method. A data transfer method in a case where a relay device configuring a wireless communication system transfers a data sequence received from one or more specific source communication devices to a destination communication device,
When an aggregation frame including only a single data frame or a data sequence of the same destination is received, after receiving the frame, only a data sequence of the same destination as the destination of the data sequence included in the received frame is received within a specific time. The same destination data sequence receiving step for receiving a single data frame or an aggregation frame as the other frames included;
In the same destination data sequence reception step, when a plurality of single data frames and / or aggregation frames are received, all the data sequences included in the received frame and the transmission source information of each data sequence, and each data sequence An aggregation frame generating step for generating an aggregation frame including the plurality of data series and destination information associated with each of the plurality of data series, based on destination information indicating the destination of
Including
The aggregation frame is
A first header area newly defined as an FAI (Frame Aggregation Subheader Indicator) as an unused area in the General MAC Header (GM header) defined in IEEE 802.16-2004 and IEEE 802.16e-2005; as more information about the data sequence included in the aggregation frame, characterized in that it comprises a data length, a second header region including address information or transmission Motojo paper, MMR header a (Mobile Multiple Relay header) composed of and to Lud over data transfer method. The aggregation frame is:
Including an MMR header containing detailed information about the first data sequence included in the frame;
Further, for the second and subsequent data series, a subheader including detailed information about the data series included in the aggregation frame is generated for each data series, and each subheader corresponds to detailed information in each subheader. 5. The data transfer method according to claim 4 , wherein the data transfer method is arranged immediately before the data series. 5. The data transfer method according to claim 4 , further comprising a unique MMR header including detailed information on all data series included in the aggregation frame. When an aggregation frame including a data series of different destinations is received, a single data transfer frame is generated for each data series based on the data series included in the aggregation frame and the destination information of each data series. One data transfer frame generation step,
The data transfer method according to any one of claims 1 to 6 , further comprising: As information indicating the length of the aggregated frame, the data transfer method according to any one of claims 1 to 7, characterized in that to use the total value of the data length included in the detailed information. If the aggregated frame contains only data series of the same length, the data transfer method according to any one of claims 1 to 8, characterized in that it comprises length information for each data series only one. The aggregation frame is
The data transfer method according to any one of claims 1 to 9 , further comprising an individual CRC (Cyclic Redundancy Check) for each data series. As the GM header or MMR header included in the aggregation frame,
A claim characterized by using an extended subheader to which an unused type number in an extended subheader type (extended subheader type) indicating an extended subheader (extended subheader) defined in IEEE 802.16e-2005 is assigned. Item 11. The data transfer method according to any one of Items 1 to 10 .

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