JP2010056765A - Wireless communication system, base station, mobile station and wireless communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a wireless communication system for further effectively using a wireless communication band. <P>SOLUTION: The wireless communication system includes: a receiving means (equivalent to 61, 62) for detecting at least one of difference between a ranging slot to which a reference signal is transmitted and reference timing, difference between a received power value and a received power reference value, and difference between a received frequency with a prescribed frequency when a base station 4 which performs ranging with a mobile station receives the reference signal for executing the ranging from the mobile station; a scheduler means (equivalent to 69, 72, 73, 74) for creating ranging response information including correction information for correcting the difference within an allowable range when it is determined that the difference detected by the receiving means is out of the allowable range; and a transmitting means (65, 61) for transmitting a MAP message for notifying transmission timing of a downlink burst signal including the ranging response information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication system that performs ranging.

  When a mobile station starts communication with a base station, a conventional wireless communication system performs ranging for correcting signal transmission timing of the mobile station and the like for the purpose of appropriately transmitting and receiving uplink signals. Specifically, the base station calculates a correction amount for the signal transmission timing, transmission power, transmission frequency, etc. of the mobile station based on the signal received from the mobile station, and notifies the mobile station of the correction information. The mobile station performs correction according to the correction information notified from the base station. Ranging is performed not only when starting communication but also after starting communication, or when the base station determines that correction is necessary (see Non-Patent Document 1 below).

IEEE P / D3 (February 2008) “Part 16: Air Interface for Broadband Wireless Access Systems” p.83-p.85, p.90-p.94, p.335-p.349, p.695-697

  However, according to the above-described conventional technique, an RNG-RSP (Ranging Response) message transmitted by the base station as a response to a CDMA (Code Division Multiple Access) code transmitted by the mobile station is a message size depending on the content of the response. Is a very short message of several bytes, but the MAC header, CRC (Cyclic Redundancy Check), and message associated with the construction of the MAC PDU (Protocol Data Unit) are used for transmission. Burst specific information including the position and size of the included burst is required. In the prior art, there is a problem that these overheads hinder effective use of the radio communication band. In addition, there is a problem that the probability that an error occurs in a message increases due to these overheads.

  In addition, in the conventional RNG-RSP message, since the mobile station cannot be identified and the radio quality cannot be specified in the base station, it is necessary to broadcast the modulation scheme and coding rate as a robust setting. There is a problem that the above-described overhead compresses the wireless communication band.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a radio communication system, a base station, a mobile station, and a radio communication method that effectively use a radio communication band when performing ranging.

  In order to solve the above-described problems and achieve the object, the present invention provides a wireless communication system that performs ranging between a base station and a mobile station, wherein the base station performs ranging from a mobile station that establishes downlink synchronization. When the specified signal for executing the specified signal is received, the difference from the reference timing in the ranging slot in which the specified signal is transmitted, the difference between the received power value and the received power reference value, the difference between the received frequency and the specified frequency Whether the difference detected by the receiving means (corresponding to the TRX unit 61 and the demodulating / decoding unit 62 in the embodiments described later) is within an allowable range or not is detected. When the difference is determined to be outside the allowable range, scheduler means (schedule) for creating ranging response information including correction information for correcting the difference within the allowable range is determined. Transmission, which includes the ranging response information in a MAP message, which is a broadcast message notifying the transmission timing of the downlink burst signal. Means (corresponding to the encoding / modulation unit 65, TRX unit 61, etc.), and included in the ranging response information when the mobile station receives a MAP message including ranging response information from the base station. Correction means (corresponding to the TRX unit 41, the demodulation / decoding unit 42, the MAP analysis unit 43, the transmission management unit 44, the encoding / demodulation unit 50, the transmission correction unit 51, etc.) for correcting according to the correction information. Features.

  According to the present invention, there is an effect that a radio communication band in ranging can be reduced.

  Embodiments of a wireless communication system 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 wireless communication system according to the present embodiment. This wireless communication system includes a network 1, a server 2, an upper station 3, a base station 4, and a mobile station 5. The network 1 is a network such as an IP (Internet Protocol) network or an ATM (Asynchronous Transfer Mode) network, and transmits and receives packets between the server 2 and the upper station 3. The upper station 3 is an access gateway device or a radio control device that accommodates the base station 4. The base station 4 is connected to the upper station 3 and transmits / receives packets such as user data and control information to / from the upper station 3. In FIG. 1, only the mobile station 5 is shown as a mobile station under the base station 4, but actually, a plurality of mobile stations are connected.

  When starting communication with the base station 4, the mobile station 5 starts ranging and transmits a CDMA code to the base station 4. When receiving the CDMA code, the base station 4 determines whether or not the mobile station 5 needs to be corrected, and generates information necessary for a ranging response. The base station 4 includes the generated information as ranging response information in a DL-MAP (Downlink MAP) message and transmits it to the mobile station 5. When the correction information is indicated by the ranging response information, the mobile station 5 performs correction according to the correction information, and then performs ranging again. The ranging operation is performed not only when the mobile station 5 starts communication with the base station 4 but also periodically after the start of communication, and the mobile station 5 transmits the CDMA code to the base station. This is also performed when an uplink bandwidth allocation is requested to 4.

  Here, before explaining the characteristics of the present embodiment, a conventional ranging method as a premise thereof will be described by focusing on the frame. For example, in mobile WiMAX (Worldwide Interoperability for Microwave Access), ranging is performed at the time of network entry by the following procedure. First, after the mobile station 5 has successfully established downlink synchronization with the base station 4, the mobile station 5 transmits a UL code such as a ranging CDMA code number and ranging area information from a UCD (Uplink Channel Descriptor) message broadcast by the base station 4. Get parameters for subframe.

  FIG. 2 is a diagram illustrating a conventional arrangement of symbols and subchannels in a frame used by a mobile station and a base station during ranging. Each frame includes a DL subframe 10-n (n = 1, 2,...) And a UL subframe 11-n. The gap between subframes is a transmission / reception switching gap. FIG. 2 shows a frame # 1 composed of DL subframe 10-1 and UL subframe 11-1, and a frame # 2 composed of DL subframe 10-2 and UL subframe 11-2. Yes.

  The DL subframe 10-1 in FIG. 2 includes a preamble 12-1, an FCH (Frame Control Header) 13-1, a DL-MAP message 14-1, and a UL-MAP 15-1. The preamble 12-1 is data for establishing synchronization at the physical layer level. The FCH 13-1 is a header that stores configuration information of the DL-MAP message 14-1. The DL-MAP message 14-1 accommodates downlink burst configuration information, and the UL-MAP 15-1 accommodates uplink burst configuration information. The UL subframe 11-1 in FIG. 2 includes a ranging area 16. The DL subframe 10-2 has the same configuration as the DL subframe 10-1, but the DL-MAP message 14-2 includes burst specific information 18 indicating information of the downlink burst 17 in itself.

  The mobile station 5 randomly selects a ranging slot arranged in the CDMA code number and the ranging area 16, and transmits the CDMA code using the selected slot. When the base station 4 detects the CDMA code transmitted by the mobile station 5, the base station 4 calculates the difference from the reference timing of the ranging slot, the difference from the received power reference value of the received power, and the difference from the specified received frequency of the received frequency. . When it is determined that these differences are outside the allowable range for starting communication, correction information is set in a response message (RNG-RSP message) and transmitted. This RNG-RSP message is transmitted in another frame (frame # 2) due to processing delay in the base station 4. That is, when the base station 4 calculates the number of slots necessary for transmitting the RNG-RSP message and assigns a downlink burst (downlink burst 17), the DL-MAP message 14-2 receives the transmission position of the downlink burst 17 and The burst specific information 18 indicating the size is set, and the DL-MAP message 14-2 and the downlink burst 17 are broadcast.

  FIG. 3 is a diagram illustrating a conventional configuration of a MAC PDU including an RNG-RSP message transmitted in a downlink burst. The MAC PDU in FIG. 3 includes a MAC header 20, an RNG-RSP message 21, and a CRC 22. The RNG-RSP message 21 includes a message type 23, CDMA code reception information 24, status reception information 25, correction information 26, and frequency change information 27. Here, the message type 23 is a message type. The CDMA code reception information 24 is information for the mobile station to determine the message destination, and includes a frame number, a symbol offset, a subchannel offset, and a CDMA code number when the base station 4 receives the CDMA code. The status reception information 25 is information indicating success or failure of ranging, and indicates one of “Success”, “Continue”, and “Abort”. For example, when the correction information 26 is provided, the mobile station 5 is notified to perform the ranging again by setting “Continue”. If there is no information to be corrected, the mobile station 5 is notified of the end of ranging by setting “Success”. When the frequency change information 27 is given, a transition to a different frequency is instructed by setting “Abort”. The correction information 26 includes information that the base station 4 determines to correct, such as the transmission timing correction amount, transmission power correction amount, and transmission frequency correction amount of the mobile station 5. The frequency change information 27 includes information for instructing a shift to a different frequency.

  FIG. 4 is a diagram illustrating a conventional configuration of a DL-MAP message (DL-MAP message 14-2). The burst specific information 18 includes a symbol offset 32 and a subchannel offset 33 as a transmission position of a downlink burst, and a symbol number 35 and a subchannel number 36 as size information. The power boost 34 is the value of the power boost applied to that subcarrier. The burst specific information 18 further includes information such as a burst profile 31 indicating the modulation scheme and coding rate of the downlink burst, and the repetition number 37 as the number of repetitions of the same information.

  Next, the radio communication system of the present embodiment will be described on the premise of the conventional ranging method as described above. FIG. 5 is a diagram illustrating a configuration example of a mobile station (mobile station 5) according to the present embodiment. The mobile station 5 includes a transmission / reception antenna 40, a TRX unit 41, a demodulation / decoding unit 42, a MAP analysis unit 43, a transmission management unit 44, a radio quality measurement unit 45, a communication control unit 46, and a packet assembly unit. 47, an upper layer unit 48, an upstream transmission buffer unit 49, an encoding / demodulating unit 50, and a transmission correcting unit 51.

  The TRX unit 41 transmits and receives radio signals to and from the base station 4 via the transmission / reception antenna 40. The demodulation / decoding unit 42 performs digital signal processing on the signal received from the base station 4 and demodulates and decodes the received signal. Then, the obtained control information and user data are output to the communication control unit 46, and a MAP message (DL-MAP message, UL-MAP) is output to the MAP analysis unit 43. The MAP analysis unit 43 acquires burst specific information for receiving a downlink burst from the MAP message and instructs the demodulation / decoding unit 42 to receive a burst. Further, as the information for transmitting the uplink signal / upstream burst from the MAP message, the upstream management unit 44 obtains the upstream bandwidth allocation information included in the UL burst (not shown) in the UL subframe of FIG. Notify Further, the MAP analysis unit 43 has a ranging response information analysis function. That is, the MAP analysis unit 43 acquires ranging response information from the MAP message and notifies the transmission management unit 44 of it.

  The communication control unit 46 generates and analyzes a control message transmitted / received to / from the base station 4 and outputs the received user data to the packet assembly unit 47. For example, when the received control message is a control message (RNG-RSP message), the ranging response information is notified to the transmission management unit 44 after analyzing the message. The packet assembling unit 47 assembles a packet addressed to the upper layer unit 48 output from the communication control unit 46. In addition, description regarding retransmission control such as hybrid ARQ (Automatic repeat-request) is omitted here.

  The transmission management unit 44 manages the transmission of signals / messages to be transmitted by the communication control unit 46 and user data from the upper layer unit 48 held in the upstream transmission buffer unit 49. Specifically, a transmission instruction of a bandwidth allocation request to the base station 4 or an uplink transmission instruction based on the upstream bandwidth allocation information notified from the MAP analysis unit 43 is performed to the encoding / modulation unit 50. . The encoding / modulation unit 50 performs encoding processing and modulation processing on the uplink transmission signal in accordance with an instruction from the transmission management unit 44. Then, the TRX unit 41 transmits the modulated signal to the base station 4 via the transmission / reception antenna 40. Further, the radio quality measurement unit 45 measures downlink radio quality information such as CINR (Carrier to Interference plus Noise Ratio) based on the received signal. Then, the TRX unit 41 transmits the measurement result processed by the encoding / modulation unit 50 in accordance with the transmission instruction of the transmission management unit 44 to the base station 4.

  Next, processing when the mobile station 5 configured as described above performs ranging will be described. When starting the ranging, the communication control unit 46 requests the transmission management unit 44 to transmit a CDMA code. The transmission management unit 44 selects a CDMA code number and a ranging slot in the upstream ranging area 16 and instructs the encoding / modulation unit 50 to transmit the CDMA code number to the base station 4. When the ranging response information is received from the base station 4 as the response, the transmission management unit 44 notifies the transmission correction unit 51 of the correction information notified from the MAP analysis unit 43 or the communication control unit 46. The transmission correction unit 51 instructs the encoding / modulation unit 50 to correct signal transmission timing, transmission power, transmission frequency, and the like. The encoding / modulation unit 50 performs correction based on the instructed correction information, and instructs the TRX unit 41 to correct the transmission frequency. In addition, when performing ranging again with the above correction, the transmission management unit 44 takes the lead and executes the same processing as described above.

  Next, the operation of the base station according to the present embodiment will be described. FIG. 6 is a diagram illustrating a configuration example of the base station (base station 4) of the present embodiment. The base station 4 includes a transmission / reception antenna 60, a TRX unit 61, a demodulation / decoding unit 62, a mapping unit 63, a radio quality management unit 64, an encoding / modulation unit 65, a wired transmission / reception unit 66, and a distribution function. Unit 67, packet holding unit 68, scheduler 69, communication control unit 70, packet assembly unit 71, correction determination unit 72, and comparison determination unit 73. The mapping unit 63 further includes a ranging response generation unit 74.

  The TRX unit 61 transmits and receives radio signals to and from the mobile station 5 via the transmission / reception antenna 60. The demodulation / decoding unit 62 performs digital signal processing on the signal received from the mobile station 5 and demodulates and decodes the received signal. Demodulation / decoding is performed based on burst specific information for receiving an uplink burst notified from the mapping unit 63. The encoding / modulating unit 65 encodes and modulates a signal to be transmitted to the mobile station 5. Then, the TRX unit 61 transmits the obtained modulated signal to the mobile station 5 via the transmission / reception antenna 60. Encoding / modulation is performed based on downlink burst specific information notified from the mapping unit 63.

  When the wired transmission / reception unit 66 receives a packet from the upper station 3, the wired transmission / reception unit 66 outputs the packet to the distribution function unit 67. The distribution function unit 67 outputs a packet of a control message transmitted / received between itself and the upper station 3 to the communication control unit 70. Further, user data packets are classified into queues 68-1 to 68-m (m = 1, 2,...) Of the packet holding unit 68 according to mobile stations and communication quality (QoS, priority, etc.). And accumulate.

  The radio quality management unit 64 measures the uplink radio quality such as CINR for the signal received from the mobile station 5, and holds the result as the uplink radio quality information. Also, downlink radio quality information reported from the mobile station 5 is held.

  The scheduler 69 determines the radio quality and QoS of each mobile station, the fairness between the mobile stations, the packet retention amount in the queues 68-1 to 68-m, the amount of control messages transmitted from the communication control unit 70 to each mobile station, and the like. Based on this, downlink bandwidth allocation is performed. Also, the modulation scheme and coding rate for downlink transmission are determined and notified to the mapping unit 63. Further, a packet corresponding to the amount of information that can be transmitted is extracted from the corresponding queue of the packet holding unit 68 or the control message received from the communication control unit 70, and a transmission packet is constructed and notified to the mapping unit 63. The packet to be extracted may be a part of the packet or a plurality of packets.

  When the scheduler 69 receives a bandwidth allocation request from the mobile station 5, the scheduler 69 performs uplink bandwidth allocation based on the radio quality and QoS of each mobile station, fairness between mobile stations, and the bandwidth request amount from the mobile station. Further, the modulation scheme and coding rate of uplink transmission are determined and notified to the mapping unit 63. Further, when the scheduler 69 receives a packet transmitted from the mobile station 5 by the uplink bandwidth allocation via the demodulation / decoding unit 62, the scheduler 69 outputs the control message to the communication control unit 70, and if it is user data, the packet assembly. To the unit 71. When the scheduler 69 distinguishes the CDMA code, control message, and user data received from the demodulation / decoding unit 62, the scheduler 69 sets the message format of the received information such as the slot (channel type) that receives the information and the connection identification information. refer. In addition, description regarding retransmission control such as hybrid ARQ is omitted here.

  The mapping unit 63 constructs a downlink MAP message including burst specific information based on the downlink packet and downlink band allocation information notified from the scheduler 69. Similarly, an uplink MAP message is constructed based on the notified uplink bandwidth allocation information. Then, a downlink transmission instruction is notified to the encoding / modulation unit 65 together with the downlink packet and the MAP message constructed above. Note that the downlink bandwidth allocation in the scheduler 69 is performed in consideration of the bandwidth for MAP message transmission constructed by the mapping unit 63.

  The packet assembling unit 71 assembles the packet, and outputs the packet assembling unit 66 when the assembling is completed. The wired transmission / reception unit 66 transmits the assembled packet to the upper station 3.

  Next, processing when the base station 4 configured as described above performs ranging will be described. When the TRX unit 61 of the base station 4 receives the CDMA code from the mobile station 5, the demodulation / decoding unit 62 detects the CDMA code, detects the difference from the reference timing of the ranging slot, and the received power reference value of the received power. Detect differences, differences in reception frequency from specified reception frequency, etc. Then, the detected difference is notified to the scheduler 69 together with the received CDMA code number, frame number, symbol offset, and subchannel offset. The scheduler 69 inquires of the correction determination unit 72 whether or not these differences are within an allowable range for starting / continuing communication. The correction determination unit 72 determines the difference received from the inquiry by comparing it with allowable ranges for predetermined reception timing, reception power, and reception frequency. If even one value is outside the allowable range, correction information including the transmission timing correction amount, transmission power correction amount, transmission frequency correction amount, etc. of the mobile station 5 is created and notified to the scheduler 69. If correction is not necessary as a result of determination, the fact is notified to the scheduler 69.

  Further, the scheduler 69 inquires of the comparison determination unit 73 whether the ranging response information including the correction information is transmitted as an RNG-RSP message or an information element of the DL-MAP message, and the comparison determination unit 73 determines Control for transmitting ranging response information is performed according to (described later). For example, when the comparison determination unit 73 determines to transmit the ranging response information as an information element of the DL-MAP message, the scheduler 69 requests the mapping unit 63 to that effect. Upon receiving the request, the ranging response generation unit 74 of the mapping unit 63 generates an information element of the DL-MAP message as ranging response information.

  On the other hand, when the comparison determination unit 73 determines to transmit the ranging response information as the RNG-RSP message, the scheduler 69 requests the communication control unit 70 to generate the RNG-RSP message. The communication control unit 70 generates an RNG-RSP message and outputs it to the scheduler 69. The scheduler 69 notifies the mapping unit 63 to transmit the RNG-RSP message. The generation of the RNG-RSP message may be performed by the scheduler 69 in order to shorten the generation processing time.

  The MAP message or RNG-RSP message generated in this way is transmitted when the mapping unit 63 instructs the encoding / modulation unit 65 to perform downlink transmission. If the correction determination unit 72 determines that correction is not necessary, a response may be made using the information element of the RNG-RSP message or MAP message. However, no correction is required in uplink bandwidth allocation performed as a response to the CDMA code. The above response may be omitted because it can also serve as a response to that effect.

  Next, the ranging operation in the radio communication system including the mobile station and the base station configured as described above will be described by focusing on the frame. FIG. 7 is a diagram illustrating an arrangement example of symbols and subchannels in a frame used by a mobile station and a base station during ranging in the radio communication system according to the present embodiment. In FIG. 7, frame # 3 equivalent to frame # 1 and frame # 4 different from frame # 2 are shown. The frame of FIG. 7 differs from the conventional frame of FIG. 2 in that a DL subframe 10-2B is provided instead of the DL subframe 10-2. The DL subframe 10-2B includes ranging response information 18B instead of the burst specific information 18, and directly transmits the information notified by the burst specific information 18 and transmitted by the downlink burst 17 using the ranging response information 18B. .

  The mobile station 5 randomly selects a ranging slot arranged in the ranging area 16 of the UL subframe 11-1 of frame # 3 and transmits a CDMA code to the base station 4. In the base station 4 that has received the CDMA code, the comparison / determination unit 73 determines whether to transmit ranging response information for the CDMA code as an RNG-RSP message or as an information element of a DL-MAP message. Specifically, the comparison determination unit 73 calculates the data length of the ranging response information when the ranging response information is transmitted as an information element of the DL-MAP message, and compares it with a predetermined threshold value. For example, when the data length of the ranging response information calculated above is equal to or less than a predetermined threshold, the comparison determination unit 73 uses the ranging response information (ranging response) as an information element of the DL-MAP message (DL-MAP message 14-2B). Information 18B) is determined to be transmitted. On the other hand, when the predetermined threshold value is exceeded, the DL-MAP message length becomes longer and the message error rate becomes higher. Therefore, it is determined that the ranging response information is transmitted in another burst using the RNG-RSP message as usual.

  The predetermined threshold is determined based on, for example, “burst specific information length” that is an information element of the DL-MAP message. In addition, the comparison determination unit 73 may perform determination based on the number of correction information included in the ranging response information 18B in order to reduce the load of the above-described data length calculation processing. That is, when the number of items of transmission timing correction amount, transmission power correction amount, and transmission frequency correction amount, which are correction contents, is equal to or smaller than a predetermined constant, it is determined that the ranging response information 18B is transmitted by the DL-MAP message 14-2B.

  FIG. 8 is a diagram illustrating a configuration example of the DL-MAP message 14-2B constructed including the ranging response information 18B. The ranging response information 18B includes CDMA code reception information 24, status reception information 25, correction information 26, and frequency change information 27, like the conventional RNG-RSP message illustrated in FIG. If there is no information to be corrected, the correction information 26 may not be included. Further, if it is not necessary to instruct a shift to a different frequency, the frequency change information 27 may not be included.

  Further, when the frame in the wireless communication system is configured not to include the burst specific information in the DL-MAP message but to include the burst specific information in the SUB-MAP separated from the DL-MAP message, the ranging response information 18B is included in the SUB. -It may be included in the MAP. FIG. 9 is a diagram illustrating an example in which ranging response information 18B is included in the SUB-MAP 19 in the DL subframe 10-2C including the SUB-MAP separated from the DL-MAP message. Compared with DL subframe 10-2B, DL subframe 10-2C includes conventional DL-MAP message 14-2 instead of DL-MAP message 14-2B, and further includes SUB-MAP19.

  In the present embodiment, the case where the CDMA code is used as the ranging method has been described, but the present invention is not limited to this. For example, the communication method of the present embodiment can be applied to any wireless communication system in which ranging is performed by a mobile station transmitting and receiving a prescribed signal at a signal transmission timing determined by a base station. In this case, the CDMA code reception information included in the ranging response information includes signal identification information corresponding to the wireless communication system, that is, information for identifying a prescribed signal received by the base station by the mobile station, Information for identifying the signal transmission timing at the mobile station can be considered. In addition, if there is information for identification by the mobile station, a plurality of transmission timings and a plurality of prescribed signals may exist.

  As described above, in this embodiment, when the ranging response information is transmitted as an information element of the DL-MAP message, when the data length of the ranging response information is equal to or less than a predetermined threshold, the ranging response information is It was decided to transmit by including in the DL-MAP message instead of the RNG-RSP message. As a result, when the message length is short, it is not necessary to transmit the overhead information that has conventionally been generated by transmitting the RNG-RSP message, so that the wireless communication band can be used effectively. In addition, loss of ranging response information due to a message error on the wireless line can be reduced.

  In this embodiment, when the data length of the ranging response information included in the DL-MAP message exceeds a predetermined threshold, the DL-MAP message length becomes longer and the message error rate becomes higher. -An RSP message is transmitted in another burst. As a result, the utilization efficiency of the radio band can be optimized and the influence on other mobile stations due to the loss of the DL-MAP message can be reduced.

Embodiment 2. FIG.
In Embodiment 1, the base station calculates the data length of the ranging response information when the ranging response information is the information element of the DL-MAP message, and uses the data length to transmit the ranging response information to the mobile station It was decided to switch. In the present embodiment, a method of transmitting a plurality of RNG-RSP messages in the same frame when a plurality of CDMA codes are received will be described. Hereinafter, processing different from that of the first embodiment will be described.

  Conventionally, when transmitting an RNG-RSP message, burst specific information set in the DL-MAP message is required for each RNG-RSP message. For this reason, when a plurality of CDMA codes are received and a plurality of RNG-RSP messages are transmitted within the same frame, the DL-MAP message length becomes longer according to the number of RNG-RSP messages.

  FIG. 10 is a diagram illustrating a configuration example of a MAC PDU including an RNG-RSP message in the present embodiment. The RNG-RSP message 21B of FIG. 10 includes the message type 23 described above, a plurality of ranging response information (corresponding to the thick frame portion in the figure), and a response information number 28 newly defined. The response information number 28 is the number of ranging response information. The ranging response information includes CDMA code reception information 24-p, status reception information 25-p, correction information 26-p, and frequency change information 27-p (p: natural number). The RNG-RSP message 21B is generated by the communication control unit 70 shown in FIG. 6 as in the first embodiment, but may be generated by the scheduler 69. Here, the scheduler 69 inquires the comparison determination unit 73 about a plurality of ranging response information to be transmitted in the same frame, and the ranging response information determined by the comparison determination unit 73 to be transmitted in the RNG-RSP message. Are included in one RNG-RSP message.

  As described above, in the present embodiment, a plurality of ranging response information is included in one RNG-RSP message. Thereby, the burst specific information set to a DL-MAP message can be made into one. Further, by combining with the configuration of Embodiment 1, it is possible to further effectively use the radio communication band and further reduce the loss rate of the DL-MAP message.

  As described above, the wireless communication system according to the present invention is useful for a wireless communication system that performs ranging, and in particular, in the system, a function in which a base station includes ranging response information in an RNG-RSP message and transmits it. Suitable for having

It is a figure which shows the structural example of a radio | wireless communications system. It is a figure which shows the conventional arrangement | positioning of the symbol and subchannel in the frame which a mobile station and a base station use at the time of ranging. It is a figure which shows the conventional structure of MAC PDU containing a RNG-RSP message. It is a figure which shows the conventional structure of a DL-MAP message. It is a figure which shows the structural example of a mobile station. It is a figure which shows the structural example of a base station. It is a figure which shows the example of arrangement | positioning of the symbol and subchannel in the frame which a mobile station and a base station use at the time of ranging. It is a figure which shows the structural example of the DL-MAP message constructed | assembled including ranging response information. It is a figure which shows the example which included ranging response information in SUB-MAP. It is a figure which shows the structural example of MAC PDU containing a RNG-RSP message.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Network 2 Server 3 Upper station 4 Base station 5 Mobile station 40 Transmission / reception antenna 41 TRX part 42 Demodulation / decoding part 43 MAP analysis part 44 Transmission management part 45 Radio quality measurement part 46 Communication control part 47 Packet assembly part 48 Upper layer part 49 Uplink transmission buffer unit 50 Encoding / demodulating unit 51 Transmission correcting unit 60 Transmitting / receiving antenna 61 TRX unit 62 Demodulating / decoding unit 63 Mapping unit 64 Radio quality management unit 65 Encoding / modulating unit 66 Wired transmitting / receiving unit 67 Distribution function unit 68 Packet holding Unit 68-m queue 69 scheduler 70 communication control unit 71 packet assembly unit 72 correction determination unit 73 comparison determination unit 74 ranging response generation unit

Claims (8)

A wireless communication system that performs ranging between a base station and a mobile station,
The base station is
When a specified signal for performing ranging is received from a mobile station that has established downlink synchronization, a difference from a reference timing in a ranging slot in which the specified signal is transmitted, a difference between a received power value and a received power reference value, Receiving means for detecting at least one of a difference between a receiving frequency and a specified frequency;
It is determined whether or not the difference detected by the receiving means is within an allowable range, and when it is determined that the difference is outside the allowable range, correction information for correcting the difference within the allowable range is included. Scheduler means for creating the ranging response information,
Transmission means for transmitting the MAP message, which is a broadcast message for notifying the downlink burst signal transmission timing, including the ranging response information;
With
The mobile station is
Correction means for performing correction according to correction information included in the ranging response information when a MAP message including ranging response information is received from the base station;
A wireless communication system comprising: The scheduler means includes
When the ranging response information is included in the MAP message and transmitted, the data length of the ranging response information is calculated, the calculated data length is compared with a predetermined threshold,
When the data length is equal to or less than a predetermined threshold, it is determined to transmit the ranging response information included in a MAP message, and notify the transmission means to that effect,
When the data length exceeds a predetermined threshold, the ranging response information is determined to be included in a downlink message different from the MAP message and transmitted, and the downlink message is generated and output to the transmission unit. The wireless communication system according to claim 1.   When the receiving means receives a prescribed signal from a plurality of mobile stations, the scheduler means adds a plurality of ranging response information determined to be included in the downlink message to be transmitted to one RNG-RSP message as the downlink message. The wireless communication system according to claim 2, wherein the wireless communication system includes and outputs to the transmission unit. When a specified signal for performing ranging is received from a mobile station that has established downlink synchronization, a difference from a reference timing in a ranging slot in which the specified signal is transmitted, a difference between a received power value and a received power reference value, Receiving means for detecting at least one of a difference between a receiving frequency and a specified frequency;
It is determined whether or not the difference detected by the receiving means is within an allowable range, and when it is determined that the difference is outside the allowable range, correction information for correcting the difference within the allowable range is included. Scheduler means for creating the ranging response information,
Transmitting means for transmitting the MAP message, which is a broadcast message notifying the downlink burst signal transmission timing, including the ranging response information;
A base station comprising: The scheduler means includes
When the ranging response information is included in the MAP message and transmitted, the data length of the ranging response information is calculated, the calculated data length is compared with a predetermined threshold,
When the data length is equal to or less than a predetermined threshold, it is determined to transmit the ranging response information included in a MAP message, and notify the transmission means to that effect,
When the data length exceeds a predetermined threshold, the ranging response information is determined to be included in a downlink message different from the MAP message and transmitted, and the downlink message is generated and output to the transmission unit. The base station according to claim 4.   When the receiving means receives a prescribed signal from a plurality of mobile stations, the scheduler means adds a plurality of ranging response information determined to be included in the downlink message to be transmitted to one RNG-RSP message as the downlink message. 6. The base station according to claim 5, wherein the base station outputs the data to the transmission unit. When a MAP message including ranging response information is received from the base station according to any one of claims 4 to 6, a correcting unit that performs correction according to correction information included in the ranging response information;
A mobile station comprising: A wireless communication method in a wireless communication system that performs ranging between a base station and a mobile station,
When the base station receives a specified signal for performing ranging from a mobile station that has established downlink synchronization, a difference from a reference timing in a ranging slot in which the specified signal is transmitted, a received power reference of a received power value A detection step of detecting at least one of a difference from a value and a difference between a reception frequency and a specified frequency;
When the base station determines whether or not the difference detected by the detection step is within an allowable range, and determines that the difference is outside the allowable range, to correct the difference within the allowable range Ranging response information creating step for creating ranging response information including correction information of
A ranging response transmission step in which the base station transmits the MAP message including the ranging response information in a MAP message that is a broadcast message for notifying a downlink burst signal transmission timing;
When the mobile station receives a MAP message including ranging response information from the base station, a correction step of performing correction according to the correction information included in the ranging response information;
A wireless communication method comprising:

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