JP2009153048A - Mobile station device, base station device, radio communication system, and retransmission method of random access preamble - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently retransmit a random access preamble. <P>SOLUTION: A mobile station device 55 applied to a radio communication system wherein any one frequency band on a frequency axis is allocated to a random access channel and disposed on a time axis at fixed time intervals and any random access channel is used to transmit a random access preamble from the mobile station device to a base station device, is provided with: a control section 53 which selects, when retransmission of the random access preamble to a base station device 40 occurs, a random access channel of a frequency band different from the frequency band of the random access channel used for the last transmission of the random access preamble; and a transmission section 61 which uses the selected random access channel to retransmit the random access preamble. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention assigns any one frequency band on the frequency axis to a random access channel and arranges it on the time axis at a certain time interval, and uses any random access channel from the mobile station apparatus to the base station apparatus. The present invention relates to a technique for retransmitting a random access preamble.

  Conventionally, in 3GPP (3rd Generation Partnership Project), the W-CDMA system has been standardized as a third generation cellular mobile communication system, and services have been started sequentially. In addition, HSDPA with higher communication speed has also been standardized and the service has started.

  On the other hand, in 3GPP, the evolution of third generation radio access (Evolved Universal Terrestrial Radio Access; hereinafter referred to as “EUTRA”) is being studied. An OFDM (Orthogonal Frequency Division Multiplexing) scheme has been proposed as a downlink of EUTRA. Further, a single carrier communication scheme of DFT (Discrete Fourier Transform) -spread OFDM scheme has been proposed as an uplink of EUTRA.

  FIG. 14 is a diagram illustrating a configuration of the downlink and uplink channels of EUTRA. The downlink of EUTRA includes downlink pilot channel DPiCH (Downlink Pilot Channel), downlink synchronization channel DSCH (Downlink Synchronization Channel), downlink shared channel PDSCH (Physical Downlink Shared Channel), downlink control channel PDCCH (Physical Downlink Control Channel). ), A common control channel CCPCH (Common Control Physical Channel).

  The uplink of EUTRA includes an uplink pilot channel UPiCH (Uplink Pilot Channel), a random access channel RACH (Random Access Channel), an uplink shared channel PUSCH (Physical Uplink Shared Channel), and an uplink control channel PUCCH (Physical Uplink Control Channel). (Non-patent Documents 1 and 2).

  Regarding the random access channel RACH, in Non-Patent Document 3, one random access channel is prepared in one subframe on the frequency axis, a plurality of random access channels are prepared in one frame, and a plurality of mobile station apparatuses It is supposed to support access from. This random access channel is notified to the mobile station apparatus as broadcast information.

  FIG. 15 is a diagram illustrating an example of an uplink configuration. Here, the horizontal axis represents time and the vertical axis represents frequency. FIG. 15 shows the configuration of one radio frame, and this radio frame is divided into a plurality of radio resources. In this example, the radio resource is configured in units of an area of 180 kHz in the frequency direction and 1 ms in the time direction. A random access channel RACH, an uplink shared channel PUSCH, and an uplink control channel PUCCH are allocated to these areas as shown in FIG. The minimum unit of the random access channel RACH uses a band of 1080 kHz.

  A unit of 1 ms in the time direction is called a subframe, and a unit of 10 ms in the time direction (10 subframes) is called a frame. FIG. 16 is a diagram illustrating a configuration example of a random access channel. As shown in FIG. 16, the random access channels are arranged at regular intervals in the time axis direction. Further, as shown in FIG. 15, the random access channel is arranged to hop at a constant period.

  The greatest purpose of using the random access channel is to synchronize the mobile station apparatus and the base station apparatus in the uplink. In addition, it is also considered to shorten the connection time by transmitting several bits of information such as a scheduling request for allocating radio resources (Non-Patent Document 2). Random access includes two access methods: Contented based Random Access and Non-contented based Random Access. Contented based Random Access is random access that may collide between mobile station apparatuses, and is normally performed random access. Non-contention based Random Access is random access in which no collision occurs between mobile station apparatuses. In order to quickly synchronize between the mobile station apparatus and the base station apparatus, it is led by the base station apparatus in a special case such as handover. Is done.

  In random access, only the preamble is transmitted for synchronization. The preamble includes a signature which is a signal pattern representing information, and several tens of types of signatures can be prepared to express several bits of information. At present, it is assumed that 6-bit information is transmitted, and it is assumed that 64 types of signatures are prepared. The 6-bit information is assumed to be assigned information such as 5 bits for random ID and the remaining 1 bit for downlink path loss / CQI (Channel Quality Indicator).

  FIG. 17 is a diagram illustrating an example of a procedure of Contented based Random Access. First, the mobile station apparatus selects a signature from a random ID, downlink path loss / CQI information, and the like, and transmits a random access preamble on the random access channel RACH (message 1 (step P1)). When the base station apparatus receives the preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, performs scheduling to transmit an L2 / L3 (Layer2 / Layer3) message, RA-RNTI (Random Access-Radio Network Temporary) indicating a response addressed to the mobile station apparatus that has assigned a temporary C-RNTI (Cell-Radio Network Temporary Identity) and transmitted a random access preamble to the random access channel RACH to the downlink control channel PDCCH Identity), and the random access including synchronization timing deviation information, scheduling information, Temporary C-RNTI, and signature ID number (or random ID) of the received preamble on the downlink shared data channel PDSCH. Response is transmitted (message 2 (step P2)).

  Upon confirming that the downlink control channel PDCCH has RA-RNTI, the mobile station apparatus confirms the content of the random access response arranged in the downlink shared data channel PDSCH, and transmits the signature ID number (or random number) of the transmitted preamble. ID) is extracted, a synchronization error is corrected, and information for identifying a mobile station apparatus such as C-RNTI (or Temporary C-RNTI) or IMSI (International Mobile Subscriber Identity) with a scheduled radio resource Is transmitted (message 3 (step P3)).

  Note that the mobile station device continues to wait for a random access response from the base station device for a certain period, and when it does not receive the random access response including the signature ID number of the transmitted preamble, it transmits the random access preamble again. When the base station apparatus receives the L2 / L3 message from the mobile station apparatus, a collision occurs between the mobile station apparatuses using C-RNTI (or Temporary C-RNTI) or IMSI included in the received L2 / L3 message. A contention resolution for determining whether or not this occurs is transmitted to the mobile station apparatus (message 4 (step P4)).

  If the mobile station apparatus does not detect the signature ID number of the preamble transmitted in the random access response, the mobile station apparatus detects the message 3 transmission failure or the identification information of the own mobile station apparatus in the contention resolution. If not, the process starts again from transmission of the random access preamble (Non-Patent Document 4).

FIG. 18 is a diagram illustrating an example of a procedure of Non-contented based Random Access. First, the base station apparatus selects a signature ID number and notifies the mobile station apparatus (message 1 (step Q1)). The mobile station apparatus uses the notified signature and transmits a random access preamble through a random access channel (message 2 (step Q2)). When the base station apparatus receives the preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, and transmits the random access preamble to the random access channel RACH to the downlink control channel PDSCH. RA-RNTI or C-RNTI indicating a response addressed to the mobile station apparatus is arranged, and a random access response including synchronization timing deviation information is transmitted (message 3 (step Q3)). The mobile station apparatus corrects the synchronization timing shift from the received random access response (Non-Patent Document 4).
3GPP TS (Technical Specification) 36.211, V1.10 (2007-05), Technical Specification Group Radio Access Network, Physical Channel and Modulation (Release 8) 3GPP TS (Technical Specification) 36.212, V1.20 (2007-05), Technical Specification Group Radio Access Network, Multiplexing and channel coding (Release 8) R1-07436, Texas Instruments, “Random Access slot Configurations”, 3GPP TSG RAN WG1 Meeting # 50, Athens, Greene, 20-24 August, 2007 3GPP TS (Technical Specification) 36.300, V8.10 (2007-06), Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Reverend ERC.

  In Contented based Random Access, when two or more mobile station apparatuses select the same signature and transmit a random access preamble simultaneously using the same random access channel, a collision of random access preambles occurs. When a collision occurs, the base station apparatus fails to detect the random access preamble, and the signature ID number of the preamble transmitted in the random access response is not included. If the preamble is successfully detected but a collision occurs during transmission of the L2 / L3 message (message 3), the base station apparatus may fail to receive message 3, or the mobile station may be included in the contention resolution. Device identification information may not be included. In such a case, the random access preamble must be retransmitted.

  In addition, when the transmission power of the transmitted random access preamble is low, or when the random access preamble does not reach the base station device due to fluctuations in the radio propagation path, the base station device cannot detect the random access preamble, so the retransmission of the random access preamble Have to do. In the case of retransmission, it is considered to increase the transmission power of the random access preamble transmitted last time or to retransmit at a later time.

  However, since details regarding retransmission of the random access preamble have not been determined, control during retransmission cannot be performed efficiently. Furthermore, frequency hopping cannot be performed efficiently when the random access preamble is retransmitted. Also, in Non-Contented based Random Access, when the mobile station apparatus cannot receive a response from the base station apparatus, it retransmits random access. Even in this case, frequency hopping cannot be efficiently performed when the random access preamble is retransmitted.

  The present invention has been made in view of such circumstances, and provides a mobile station apparatus, a base station apparatus, a radio communication system, and a random access preamble retransmission method capable of performing efficient retransmission of a random access preamble. The purpose is to do.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the mobile station apparatus of the present invention allocates any one frequency band on the frequency axis to the random access channel, arranges it on the time axis at a certain time interval, and uses any random access channel to A mobile station apparatus that is applied to a radio communication system that transmits a random access preamble to a base station apparatus from the apparatus, and when retransmission of the random access preamble to the base station apparatus occurs, at the time of transmission of the previous random access preamble A control unit that selects a random access channel having a frequency band different from the frequency band of the used random access channel, and a transmission unit that retransmits the random access preamble using the selected random access channel. Yes.

  As described above, when retransmission of the random access preamble to the base station apparatus occurs, a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble is selected, and the selected random access is selected. Since retransmission of a random access preamble is performed using a channel, frequency hopping can be performed, and retransmission having a frequency diversity effect can be performed.

  (2) Moreover, in the mobile station apparatus of the present invention, when retransmission of the random access preamble to the base station apparatus occurs, the control unit determines that the frequency band of the latest random access channel is the same as that of the previous random access preamble transmission. When the same frequency band as the used random access channel, the retransmission of the random access preamble is suspended and the subsequent random access channel is different from the frequency band of the random access channel used at the time of the previous random access preamble transmission. A random access channel of a band is selected, and the transmission unit retransmits a random access preamble using the selected random access channel.

  With this configuration, when the random access load is low, frequency hopping can be performed for the random access channel, and retransmission having a frequency diversity effect can be performed.

  (3) Further, in the mobile station apparatus of the present invention, when retransmission of a random access preamble to the base station apparatus occurs, the control unit selects a plurality of random access channels within a certain period as selection candidates, and selects the selection candidates. Random access channel having a frequency band different from the frequency band of the random access channel used when the random access preamble was transmitted last time is selected from the random access channels, and the transmission unit uses the selected random access channel to perform random access. The access preamble is retransmitted.

  With this configuration, when the random access load is high, frequency hopping can be performed for the random access channel, and retransmission having a frequency diversity effect can be performed.

  (4) The mobile station apparatus of the present invention allocates any one frequency band on the frequency axis to the random access channel, arranges it on the time axis at a constant time interval, and uses any random access channel. A mobile station apparatus that is applied to a radio communication system that transmits a random access preamble from a mobile station apparatus to a base station apparatus, wherein a plurality of transmission antennas and retransmission of the random access preamble to the base station apparatus have occurred If the frequency band of the last random access channel is the same as the frequency band of the random access channel used during the previous random access preamble transmission, select a transmission antenna that is different from the transmission antenna used during the previous random access preamble transmission. On the other hand, the most recent random access The control unit for selecting the same transmission antenna as the transmission antenna used at the time of the previous random access preamble transmission when the frequency band of the channel is different from the frequency band of the random access channel used at the time of the previous random access preamble transmission; And a transmitter that retransmits the random access preamble using the latest random access channel with the transmitted antenna.

  Thus, when retransmission of the random access preamble to the base station apparatus occurs, if the frequency band of the latest random access channel is the same as the frequency band of the random access channel used at the time of transmission of the previous random access preamble, Select a transmission antenna that is different from the transmission antenna used when transmitting the access preamble, but if the frequency band of the most recent random access channel is different from the frequency band of the random access channel that was used during the previous transmission of the random access preamble, Select the same transmission antenna as that used when transmitting the random access preamble, and retransmit the random access preamble using the nearest random access channel with the selected transmission antenna. Since performed, if the random access load is low, it is possible to the antenna hopping, it is possible to perform the retransmission with the antenna diversity effect.

  (5) Also, the mobile station apparatus of the present invention allocates any one frequency band on the frequency axis to the random access channel, arranges it on the time axis at a constant time interval, and uses any random access channel. A mobile station apparatus that is applied to a radio communication system that transmits a random access preamble from a mobile station apparatus to a base station apparatus, wherein a plurality of transmission antennas and retransmission of the random access preamble to the base station apparatus have occurred In this case, a plurality of random access channels within a certain period are selected as selection candidates, and a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the random access preamble is selected from the random access channel of the selection candidate. When selecting the last random access While selecting the same transmission antenna as the transmission antenna used when transmitting the preamble, a random access channel having the same frequency band as the random access channel used when transmitting the previous random access preamble is selected from the selected random access channel. When selecting, a control unit that selects a transmission antenna different from the transmission antenna used at the time of transmission of the previous random access preamble, and the random access preamble of the random access preamble using the selected random access channel with the selected transmission antenna. And a transmission unit that performs retransmission.

  In this way, when retransmission of the random access preamble to the base station apparatus occurs, a plurality of random access channels within a certain period are selected as selection candidates, and used at the time of the previous random access preamble transmission from the selection candidate random access channels. When selecting a random access channel of a frequency band different from the frequency band of the random access channel, while selecting the same transmission antenna as the transmission antenna used during the transmission of the previous random access preamble, from the random access channel of the selection candidate, When selecting a random access channel that has the same frequency band as the random access channel that was used when the previous random access preamble was transmitted, it is used when the previous random access preamble was transmitted. A transmission antenna different from the transmission antenna is selected, and the selected transmission antenna is used to retransmit the random access preamble using the selected random access channel, so that antenna hopping is performed when the random access load is high. Thus, it is possible to perform retransmission having an antenna diversity effect.

  (6) Moreover, the base station apparatus of this invention allocates any one frequency band on a frequency axis to a random access channel, arrange | positions on a time axis at a fixed time interval, and uses any random access channel. 6. A base station apparatus applied to a radio communication system that transmits a random access preamble from a mobile station apparatus to a base station apparatus, comprising: random access from a mobile station apparatus according to claim 1; A base station side receiving unit that receives a preamble, a calculating unit that calculates a retransmission time interval when the mobile station apparatus retransmits a random access preamble based on the received random access preamble, and the calculated retransmission time interval And a base station side transmitting unit that transmits information indicating the above to the mobile station apparatus.

  With this configuration, when retransmission of the random access preamble occurs in the mobile station apparatus, a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble is selected, and the selected random access channel is selected. It is possible to retransmit the random access preamble using the access channel. As a result, frequency hopping can be performed in the mobile station apparatus, and retransmission having a frequency diversity effect can be performed.

  (7) Also, in the wireless communication system of the present invention, any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a constant time interval, and any one of the random access channels is used. A wireless communication system for transmitting a random access preamble from a mobile station device to a base station device, wherein the mobile station device according to any one of claims 1 to 5 and the base station device according to claim 6 It is characterized by comprising.

  With this configuration, when a random access preamble is retransmitted to the base station apparatus, a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble is selected, and the selected random access is selected. Since retransmission of a random access preamble is performed using a channel, frequency hopping can be performed, and retransmission having a frequency diversity effect can be performed.

  (8) Further, according to the random access preamble retransmission method of the present invention, any one of the frequency bands on the frequency axis is allocated to the random access channel and arranged on the time axis at a constant time interval. A random access preamble retransmission method for transmitting a random access preamble from a mobile station apparatus to a base station apparatus using a channel, wherein the mobile station apparatus retransmits a random access preamble to the base station apparatus Selecting a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble, and retransmitting the random access preamble using the selected random access channel. To have.

  As described above, when retransmission of the random access preamble to the base station apparatus occurs, a random access channel having a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble is selected, and the selected random access is selected. Since retransmission of a random access preamble is performed using a channel, frequency hopping can be performed, and retransmission having a frequency diversity effect can be performed.

  According to the present invention, it is possible to efficiently perform frequency hopping or antenna hopping when retransmitting a random access preamble, and to perform retransmission capable of obtaining a frequency diversity effect or an antenna diversity effect.

(First embodiment)
Next, an embodiment according to the present invention will be described with reference to the drawings. In the radio communication system according to the present embodiment, the arrangement positions of the random access channels are arranged at regular intervals on the time axis as shown in FIG. 15, and one random access channel (random access resource) on the frequency axis. Have Further, a system that hops at regular intervals between a low frequency band and a high frequency band is assumed.

  When resending the random access preamble, two cases are conceivable. One is when the random access load is low, and the other is when the random access load is high. The random access load is determined by the number of random access preambles received by the base station device, and the random access load status is notified from the base station device to the mobile station device.

  The reason for retransmission when the random access load is low is that the transmission power of the random access preamble is lower than the collision of random access preambles between mobile station devices, or the main cause is due to the influence of the radio propagation path Conceivable. When retransmitting, it is effective to increase the transmission power of the random access preamble or to transmit the random access preamble at different frequency positions in order to obtain the frequency diversity effect.

  The reason for retransmission when the random access load is high is considered to be mainly due to collision of random access preambles between mobile station apparatuses. In the case of retransmission, it is effective to distribute random access on the time axis so that the mobile station apparatuses to be retransmitted do not collide again. Of course, it is also effective to increase the transmission power of the random access preamble or to transmit the random access preamble at different frequency positions in order to obtain the frequency diversity effect.

  For this reason, when retransmitting the random access preamble, the mobile station apparatus differs from the frequency position used for the previous random access preamble transmission from the time positions (random access opportunities) of the random access channel that can be transmitted. Select and transmit the time position of the random access channel at the frequency position. Further, random access is distributed on the time axis according to the random access load.

  In other words, if the random access load is low and it is determined that the random access response has not been successfully received (such as when the random access preamble transmission fails or when the random access response reception fails), the random access response The access transmission process is executed immediately. The frequency position of the random access channel is confirmed, and if the frequency position is different from the frequency position where the previous random access preamble was transmitted, the random access preamble is transmitted. On the other hand, if the frequency position is the same as the frequency position where the previous random access preamble was transmitted, it waits until the time position of the random access channel at a different frequency position (random access is suspended or postponed), and the random access channel at a different frequency position. The random access preamble is retransmitted when the time position is reached. Note that the reselected signature is used as the signature of the random access preamble to be retransmitted.

  Also, if it is determined that the random access response has not been successfully received when the random access load is high (for example, when the random access preamble transmission fails or when the random access response reception fails), within a certain period of time. The time position of the random access channel is selected from among random access channels (between several frames or several random access channels). If the selected random access channel is a random access channel with the same frequency position as the frequency position where the previous random access preamble was transmitted, the time position of the random access channel is reselected and the frequency position where the random access preamble was transmitted last time Random access preambles are transmitted on random access channels at different frequency positions.

  When the number of random access retransmissions exceeds a certain threshold, the failure of the random access procedure is detected, notified to the upper layer, and reset from the upper layer.

  FIG. 1 is a diagram illustrating how a random access preamble is retransmitted when the random access load is low. It is assumed that the mobile station apparatus transmits a random access preamble through a random access channel with a random access number 1. If the mobile station device does not receive a random access response including the signature number of the random access preamble transmitted by the mobile station device within the random access reception period, the mobile station device determines the position of the random access channel after the random access response reception period. Check.

  Since the second random access channel of the b frame shown in FIG. 1 is at the same frequency position as the previously transmitted random access channel, the mobile station apparatus waits for retransmission until the next random access channel. Since the third random access channel of the b frame is at a different frequency position from the previously transmitted random access channel, the mobile station apparatus transmits a random access preamble using the third random access channel of the b frame.

  FIG. 2 is a diagram illustrating how the random access preamble is retransmitted when the random access load is high. It is assumed that the mobile station apparatus transmits a random access preamble through a random access channel with a random access number 1. If the mobile station apparatus does not receive a random access response including the signature number of the random access preamble transmitted by the mobile station apparatus within the random access reception period, the mobile station apparatus selects from the random access channels within a certain period. Select the time position of the random access channel. Then, the mobile station apparatus confirms the frequency position of the selected random access channel, and if it is the same random access channel as the frequency position of the previously transmitted random access channel, selects the random access time position again, and selects a different frequency position. Select until the random access channel is reached. Then, the mobile station apparatus transmits a random access preamble using the selected random access channel.

  In FIG. 2, when the range of the fixed period is 2 frames, the random access channel is randomly selected from the second random access channel of the b frame and the first random access channel of the d frame. If the first random access channel of c frame is selected, the frequency position is the same frequency position as the previously transmitted random access preamble, so the mobile station apparatus selects a random access channel again and selects a different frequency position. Repeat selection until. FIG. 2 shows a case where the mobile station apparatus selects and retransmits c-frame number 2.

  FIG. 3 is a diagram illustrating how the random access preamble is retransmitted when the random access load is high. The mobile station apparatus calculates a time position of a random access channel that is different from the frequency position of the previously transmitted random access channel from random access channels within a certain period of time, and includes the random access channel at the calculated time position. Random access channel is selected at random. In FIG. 3, assuming that the range of a certain period is 2 frames, the mobile station apparatus selects the random access channel number of the b frame at a different frequency position from the random access channel of the second frame to the random access channel of the d frame. 3. Random access channel number 2 for c frame and random access channel number 1 for d frame are calculated. Using these three random access channels as selection candidates, an appropriate random access channel is selected from these candidates. FIG. 3 shows a case where the mobile station apparatus selects c-frame random access channel number 2. The mobile station apparatus transmits a random access preamble using the selected random access channel.

  FIG. 4 is a block diagram illustrating a schematic configuration of the base station apparatus according to the first embodiment. The base station apparatus 40 includes a data control unit 41, an OFDM modulation unit 42, a scheduling unit 43, a channel estimation unit 44, a DFT-S-OFDM (DFT-Spread-OFDM) demodulation unit 46, a control data extraction unit 47, a preamble detection unit. 48, a synchronization timing measurement unit 49, and a radio unit 50. The scheduling unit 43 includes a DL scheduling unit 43a, a UL scheduling unit 43b, and a control data creation unit 43c.

  The data control unit 41 processes the input user data and control data according to an instruction from the scheduling unit 43. That is, the scheduling unit 43 maps the control data to the downlink control channel PDCCH, the downlink synchronization channel DSCH, the downlink pilot channel DPiCH, the common control channel CCPCH, and the downlink shared channel PDSCH, and transmits transmission data ( User data) is mapped to the downlink shared channel PDSCH.

  The OFDM modulation unit 42 performs data signal modulation, serial / parallel conversion of the input signal, performs OFDM signal processing such as IFFT (Inverse Fast Fourier Transform) conversion, CP (Cyclic Prefix) insertion, and filtering, and generates an OFDM signal. The radio unit 50 up-converts OFDM-modulated data to a radio frequency and transmits it to the mobile station apparatus. Further, the radio unit 50 receives uplink data from the mobile station apparatus, down-converts it into a baseband signal, and converts the received data into a channel estimation unit 44, a DFT-S-OFDM demodulation unit 46, and a preamble detection unit. 48 and the synchronization timing measurement unit 49.

  The channel estimation unit 44 estimates the radio channel characteristics from the uplink pilot channel UPiCH, and outputs the radio channel estimation result to the DFT-S-OFDM demodulation unit 46. In addition, a radio channel estimation result is output to the scheduling unit 43 in order to perform uplink scheduling from the uplink pilot channel UPiCH. The uplink communication scheme is assumed to be a single carrier scheme such as DFT-S-OFDM, but may be a multicarrier scheme such as the OFDM scheme.

  The control data extraction unit 47 confirms the correctness of the received data and notifies the scheduling unit 43 of the confirmation result. If the received data is correct, the received data is separated into user data and control data. Among the control data, layer 2 control data such as downlink CQI information and downlink data ACK / NACK are output to the scheduling unit 43, and other layer 3 control data and user data are output to the upper layer. To do. If the received data is incorrect, it is stored for combining with the retransmitted data, and the combining process is performed when the retransmitted data is received.

  The scheduling unit 43 includes a DL scheduling unit 43a that performs downlink scheduling, a UL scheduling unit 43b that performs uplink scheduling, and a control data creation unit 43c. The DL scheduling unit 43a transmits user data and control data to each downlink channel from CQI information notified from the mobile station device, data information of each user notified from the upper layer, and control data generated by the message generating unit. Schedule for mapping. The UL scheduling unit 43b performs scheduling for mapping user data to each uplink channel from the uplink radio channel estimation result input from the channel estimation unit 44 and the resource allocation request received from the mobile station apparatus. The control data creation unit 43c stores information on random access such as uplink data ACK / NACK, random access channel configuration (random access opportunity, hopping pattern, etc.) and information indicating random access transmission status (random access load). Control data such as a broadcast information message, a random access response message, and a contention resolution message are generated.

  The preamble detection unit 48 detects a preamble from the received signal, calculates a synchronization timing shift amount, and reports the signature ID number and the synchronization timing shift amount to the scheduling unit 43. Further, the scheduling unit 43 is also notified of the random access transmission status of the mobile station apparatus periodically from the number of received random access preambles. Further, the transmission range of the preamble retransmission (the number of random access channels or the number of frames) is calculated from the transmission status of the random access preamble transmission, and is notified to the scheduling unit 43.

  The synchronization timing measurement unit 49 measures the uplink pilot channel UPiCH to maintain synchronization, measures a synchronization timing shift, and reports the measurement result to the scheduling unit 43.

  FIG. 5 is a block diagram showing a schematic configuration of the mobile station apparatus according to the first embodiment. The mobile station apparatus 55 includes a data control unit 51, a DFT-S-OFDM (DFT-Spread-OFDM) modulation unit 52, a scheduling unit 53, an OFDM demodulation unit 54, a channel estimation unit 56, a control data extraction unit 57, and a synchronization correction unit. 58, a preamble generation unit 59, a signature selection unit 60, and a radio unit 61. The scheduling unit 53 includes a UL scheduling unit 53a, a control data analysis unit 53b, a control data creation unit 53c, and a RACH calculation unit 53d. The scheduling unit 53 constitutes a control unit, and the radio unit 61 constitutes a transmission unit.

  User data and control data are input to the data control unit 51. The data control unit 51 is arranged to transmit user data and control data on the uplink shared channel PUSCH and the uplink control channel PUCCH according to an instruction from the scheduling unit 53. Further, the data control unit 51 arranges an uplink pilot channel UPiCH. The DFT-S-OFDM modulation unit 52 performs data modulation, performs DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, etc., and DFT-Spread-OFDM Generate a signal. The uplink communication scheme is assumed to be a single carrier scheme such as DFT-Spread-OFDM, but it may be a multicarrier scheme such as the OFDM scheme.

  The synchronization correction unit 58 corrects the transmission timing from the synchronization information input from the control data extraction unit 57 and outputs data modulated to match the transmission timing to the radio unit 61. Radio section 61 sets a predetermined radio frequency to a frequency to be used, up-converts the modulated data to a radio frequency, and transmits the radio data to the base station apparatus. Also, the radio unit 61 receives downlink data from the base station apparatus, down-converts it to a baseband signal, and outputs the received data to the OFDM demodulator 54.

  The channel estimation unit 56 estimates radio channel characteristics from the downlink pilot channel DPiCH and outputs the estimation result to the OFDM demodulation unit 54. Further, in order to notify the base station apparatus of the radio channel estimation result, the estimated radio channel characteristic is converted into CQI information, and the CQI information is output to 53 in the scheduling unit. The OFDM demodulator 54 demodulates the received data from the radio channel estimation result of the channel estimator 56. The control data extraction unit 57 separates the received data into user data and control data. Among the control data, uplink synchronization information is output to the synchronization correction unit 58, scheduling information and other layer 2 control data are output to the scheduling unit 53, and layer 3 control data and user data are output to the upper layer. .

  The signature selection unit 60 selects a signature ID number used in random access according to an instruction from the scheduling unit 53, and outputs the selected signature ID number to the preamble generation unit 59. The preamble generation unit 59 generates a random access preamble including a signature corresponding to the signature ID number selected by the signature selection unit 60, and outputs the random access preamble to the DFT-S-OFDM modulation unit 52.

  In the scheduling unit 53, the control data analysis unit 53b analyzes the control information input from the control data extraction unit 57, outputs the scheduling information to the UL scheduling unit 53a, and determines the synchronization timing included in the random access response or the synchronization information. Information is output to the synchronization correction unit 58. Further, the control data analysis unit 53b outputs a broadcast information message including information on random access transmission such as information indicating the configuration of the random access channel and the transmission status of the random access to the signature selection unit 60 and the RACH calculation unit 53d. Further, the control data analysis unit 53b instructs the control data creation unit 53c to return ACK.

  The control data creation unit 53 c creates ACK / NACK and other control data and outputs them to the data control unit 51. The UL scheduling unit 53a causes the data control unit 51 to map data and control information to each uplink channel based on scheduling information input from an upper layer and control information input from the control data analysis unit 53b. Instruct.

  The RACH calculation unit 53d selects the position (frequency position, time position, etc.) of the random access channel RACH from the notified random access transmission-related information and the retransmission status (the previously transmitted frequency position, the number of retransmissions, etc.). Also, a random access channel that transmits a random access preamble is selected. In addition, the scheduling unit 53 instructs the signature selection unit 60 to perform random access according to an instruction from an upper layer.

  FIG. 6 is a flowchart illustrating an operation example of the mobile station apparatus according to the first embodiment. First, the mobile station apparatus acquires information on random access broadcast from the base station apparatus (step S1), resets the number of random access transmissions (step S2), and enters a random access channel selection process. It is determined whether the transmission is initial transmission (step S3). If the transmission is initial transmission, the random access channel closest in time is selected from the configuration of the random access channel in the acquired random access information, and the random transmission channel is selected. The access transmission process starts.

  On the other hand, in the case of retransmission in step S3, the time position of the random access channel closest in time is confirmed. It is determined whether or not the frequency position of the random access channel is a random access channel having the same frequency position as that of the previously transmitted random access channel (step S4). (Step S5). On the other hand, in the case of different frequency positions in step S4, the random access transmission process is entered.

  In the random access transmission process, a signature to be included in the random access preamble is selected (step S6), a random access preamble is generated, and the random access preamble is transmitted using the selected random access channel (step S7). After transmitting the random access preamble, a random access response reception process is performed.

  It is determined whether or not a random access response included in the signature ID number of the random access preamble transmitted within the random access response reception period has been received (step S8). If not received, retransmission preparation processing is performed. In the retransmission preparation process, it is determined whether or not the maximum number of random access transmissions (the maximum number of random access preambles including retransmissions performed in one random access) has been exceeded (step S9). If this happens, the upper layer is notified (step S10), and the random access is terminated.

  If the maximum number of random access transmissions is not exceeded in step S9, the number of random access transmissions is counted up (step S11). Next, it is determined whether or not the random access load is high (step S12). When the random access addition is high, a random access channel time position within a certain range is selected at random, and the process waits for the selected time position (step S12). S13). Then, the process proceeds to step S3, and a random access channel selection process is performed. On the other hand, if the random access load is low in step S12, the process proceeds to step S3 to perform a random access channel selection process.

  In step S8, when a random access response including the signature ID number of the random access preamble transmitted by the mobile station apparatus is received within the random access response reception period, the L2 / L3 message transmission process is executed. That is, before transmitting the L2 / L3 message, the uplink transmission timing is corrected from the synchronization timing shift information included in the random access response (step S14). Next, an L2 / L3 message is created (step S15), and the L2 / L3 message is transmitted to the base station apparatus (step S16). A response to the L2 / L3 message is confirmed from the base station apparatus, and it is determined whether or not the L2 / L3 message has been successfully transmitted (step S17). When the transmission of the L2 / L3 message is successful, it waits for the contention resolution message reception period, the contention resolution message from the base station apparatus, and determines whether or not the contention resolution message has been received ( Step S18). When the contention resolution message is received, the random access is terminated.

  If transmission of the L2 / L3 message fails in step S17, the process proceeds to step S9, and retransmission preparation processing is performed. If no contention resolution message is received in step S18, the process proceeds to step S9 to perform retransmission preparation processing.

  FIG. 7 is a flowchart showing another operation example of the mobile station apparatus according to the first embodiment. The mobile station apparatus acquires information on random access broadcast from the base station apparatus (step T1), resets the number of random access transmissions (step T2), and enters a random access channel selection process. In the case of initial transmission, the random access channel that is closest in time is selected from the configuration of the random access channel in the acquired random access information, and in the case of retransmission, the time position selected in the retransmission preparation process is selected. A random access channel is selected (step T3).

  In the random access transmission process, a signature to be included in the random access preamble is selected (step T4), a random access preamble is generated, and the random access preamble is transmitted through the selected random access channel (step T5). After transmitting the random access preamble, a random access response reception process is performed.

  It is determined whether or not a random access response included in the signature ID number of the random access preamble transmitted during the random access response reception period has been received (step T6). If not received, retransmission preparation processing is performed. In the retransmission preparation process, it is determined whether or not the maximum number of random access transmissions (the maximum number of random access preambles including retransmission performed in one random access) has been exceeded (step T7). If this happens, the upper layer is notified (step T8), and the random access is terminated. On the other hand, if the maximum number of random access transmissions is not exceeded in step T7, the number of random access transmissions is counted up (step T9), and it is determined whether the random access load is high (step T10).

  In step T10, when the random access load is high, the position of the random access channel within a certain range (back-off selection period) in which transmission is possible is confirmed, and the frequency transmitted last time in the random access channel time position within the certain range. A time position is randomly selected from random access channels different from the position (step T11). As one selection method, a time position is randomly selected from random access channel time positions within a certain range, and the frequency position of the selected random access channel is confirmed. If the selected random access channels are at the same frequency position, a random access channel time position within a certain range is selected again at random, and this is repeated until a random access channel at a different frequency position is selected.

  Another selection method is to randomly select a time position from among random access channel time positions within a certain range, confirm the frequency position of the selected random access channel, and select the random access channel to the same frequency position. In the case of (2), a random access channel at a different frequency position that is closest in time is selected. As another selection method, the random function configuration (frequency position pattern) of the setting information related to the random access and the frequency position at which the previous random access preamble was transmitted is added as the input of the random function, and the random function is output. Always outputs the time position of the random access channel different from the frequency position at which the previous random access preamble was transmitted.

  For example, in the case of a random access channel structure that changes the frequency position in units of subframes, an even number of random access subframe numbers (for example, the random access channel exists at a higher frequency position) and an odd number (for example, random access channel) May be output from a random function. Also, for example, in the case of a random access channel structure in which the frequency position is changed in units of frames, the even number of the frame number (for example, the random access channel exists at a high frequency position) and the odd number (for example, the frequency of the random access channel is low) Any one of them may be output from a random function.

  Next, while waiting for the selected time position (back-off time), the process proceeds to step T3 to enter a random access channel selection process.

  On the other hand, if the random access load is low in step T10, it is determined whether or not the frequency position is the same as the previous time (step T12). If the frequency position is not the same as the previous time, the process proceeds to step T3 and the random access is performed. The channel selection process starts. In step T12, if it is the same frequency position as the previous time, it waits until the next random access channel (step T13), and the determination in step T12 is performed.

  In step T6, when the random access response including the signature ID number of the random access preamble transmitted by the mobile station apparatus is received within the random access response reception period, the transmission process of the L2 / L3 message is executed. That is, before transmitting the L2 / L3 message, the uplink transmission timing is corrected from the synchronization timing shift information included in the random access response (step T14). Next, an L2 / L3 message is created (step T15), and the L2 / L3 message is transmitted to the base station apparatus (step T16). A response to the L2 / L3 message is confirmed from the base station apparatus, and it is determined whether or not the L2 / L3 message has been successfully transmitted (step T17). When the transmission of the L2 / L3 message is successful, it waits for the contention resolution message reception period, the contention resolution message from the base station apparatus, and determines whether or not the contention resolution message has been received ( Step T18). When the contention resolution message is received, the random access is terminated.

  On the other hand, if transmission of the L2 / L3 message has failed in step T17, the process proceeds to step T7, and retransmission preparation processing is performed. If no contention resolution message is received in step T18, the process proceeds to step T7, and retransmission preparation processing is performed.

  Next, the operation of the base station apparatus according to this embodiment will be described. When the base station apparatus receives the random preamble from the mobile station apparatus, the base station apparatus calculates a synchronization timing shift between the mobile station apparatus and the base station apparatus from the preamble, and performs scheduling to transmit an L2 / L3 (Layer2 / Layer3) message. . Then, a Temporary C-RNTI (Cell-Radio Network Temporary Identity) is assigned, and a RA-RNTI (Random Access-Radio) indicating a response addressed to the mobile station apparatus that has transmitted the random access preamble to the random access channel RACH to the downlink control channel PDCCH. Network Temporary Identity) is arranged, and a random access response including synchronization timing shift information, scheduling information, Temporary C-RNTI, and signature ID number of the received preamble is transmitted to the downlink shared data channel PDSCH. When receiving the L2 / L3 message from the mobile station apparatus, the contention resolution is transmitted to the mobile station apparatus.

  In addition, the base station apparatus counts and averages the number of random access preambles received in each random access channel, determines “more / less” transmission of the random access preamble of the mobile station apparatus, and determines the result as the random access channel The information is included in information related to random access such as the configuration of the mobile station apparatus and notified to the mobile station apparatus. Further, the transmission range of the preamble retransmission (the number of random access channels or the number of frames) is calculated from the transmission status of the random access preamble transmission of the mobile station apparatus, and is included in information on random access and notified to the mobile station apparatus. For example, the case where there are many transmissions of the random access preamble transmission status is divided into two stages (the most / the most). When the transmission status is the highest, the number of retransmittable random access channels is 10, and when there are many, the retransmission is performed. The number of possible random access channels is five. Then, the mobile station apparatus is notified by including it in information related to random access.

  As described above, according to the first embodiment, frequency hopping can be performed, and retransmission having a frequency diversity effect can be performed.

  As a modification, a case where the configuration of the random access channel is different will be described. For example, in FIG. 15, resources for the uplink control channel PUCCH may be changed. In this case, the random access channel is shifted by one block for the uplink control channel PUCCH. In the above embodiment, control in the case of the same frequency at the time of retransmission of random access has been described. However, when resources for the uplink control channel PUCCH are changed, the frequency may not be completely the same. Therefore, in a random access channel arrangement, a random access channel existing at a high frequency position is simply defined as a random access channel 1 and a random access channel existing at a low frequency position is defined as a random access channel 2, and the random access used last time is defined. If the random access channel 1 is used, the random access channel 2 may be used for retransmission. That is, two random access channel structures are defined, and retransmission is performed in a subframe having a structure different from the subframe in which random access was previously performed. Therefore, the portion described as the frequency position in the above embodiment can also be described as a subframe structure.

(Second Embodiment)
In this embodiment, a case where a plurality of transmission antennas are provided will be described. In the first embodiment, the random access channel to be retransmitted uses a random access channel at a frequency position different from the frequency position of the previously transmitted random access channel, so that a frequency diversity effect can be obtained when retransmitting. I was doing. In the present embodiment, the same idea is adopted, and when there are a plurality of antennas, the diversity effect is obtained by switching the transmission antennas.

  In other words, when the random access load is low and it is determined that the random access response has not been successfully received (for example, when the random access preamble transmission fails or when the random access response reception fails), the random access The transmission process is executed immediately. The frequency position of the random access channel is confirmed. If the frequency position is the same as that at the previous transmission, an antenna different from the antenna at the previous transmission is selected as the transmission antenna. On the other hand, if the frequency position is different from the previous transmission, the same antenna as the previous transmission is selected as the transmission antenna, and the random access preamble is transmitted. As a result, the time required for retransmission is shortened, and a diversity effect can be obtained regardless of the frequency position of the previous random access channel.

  Also, if the random access load is high and it is determined that the random access response has not been successfully received (for example, if the random access preamble transmission fails or if the random access response reception fails), a certain period Select the time position of the random access channel from the random access channels within (several frames or several random access channels), and if the random access channel has the same frequency position as the frequency position where the random access preamble was transmitted last time, A random access preamble is transmitted by selecting an antenna different from the transmitted antenna. On the other hand, in the case of a random access channel having a frequency position different from the frequency position transmitted last time, the same antenna as the previous time is selected and a random access preamble is transmitted. When the number of random access retransmissions exceeds a certain threshold, the failure of the random access procedure is detected, notified to the upper layer, and reset from the upper layer.

  FIG. 8 and FIG. 9 are diagrams illustrating how the random access preamble is retransmitted when the random access load is low. First, as shown in FIG. 8, it is assumed that the mobile station apparatus transmits a random access preamble using a transmission antenna 1 through a random access channel with a random access number 1. If the mobile station device does not receive a random access response including the signature number of the random access preamble transmitted by the mobile station device within the random access reception period, the mobile station device determines the position of the random access channel after the random access response reception period. Confirm and select the random access channel of random access number 2 of the nearest b frame. Since the mobile station apparatus is at the same frequency position as the frequency position of the previously transmitted random access channel, the mobile station apparatus transmits a random access preamble using an antenna 2 different from the previously transmitted antenna 1.

  Next, as shown in FIG. 9, it is assumed that the mobile station apparatus transmits a random access preamble using a transmission antenna 1 on a random access channel with a random access number 1. If the mobile station device does not receive a random access response including the signature number of the random access preamble transmitted by the mobile station device within the random access reception period, the mobile station device determines the position of the random access channel after the random access response reception period. Confirm and select the random access channel of random access number 1 of the nearest b frame. Since the mobile station apparatus has a frequency position different from the frequency position of the previously transmitted random access channel, the mobile station apparatus transmits a random access preamble using the same antenna 1 as the previously transmitted antenna 1.

  10 and 11 are diagrams illustrating a state of retransmission of the random access preamble when the random access load is high. It is assumed that the mobile station apparatus transmits a random access preamble using a transmission antenna 1 on a random access channel with a random access number 1. If the random access response that includes the signature number of the random access preamble transmitted by the mobile station device within the random access reception period is not received, check the position of the random access channel after the random access response reception period. Several consecutive random access channels (or random access channels for several frames) from near random access channels are set as retransmittable random access channels.

  Here, the number of retransmittable random access channels is five. The random access channels that can be retransmitted are the random access channel number 2 and random access channel number 3 of the b frame, the random access channel number 1 of the c frame, the random access channel number 2 and the random access channel number 3 of the random access channel number 3. . Then, the time position of one random access channel is randomly selected from the five random access channels, the frequency position of the selected random access channel is confirmed, and the antenna to be transmitted is determined. If the selected random access channel is b-frame random access channel number 2 and c-frame random access channel number 1 and random access channel number 3, the frequency position is the same as the previously transmitted frequency position. Is switched to antenna 2 and a random access preamble is transmitted.

  In addition, when the selected random access channel is the random access channel number 3 of b frame and the random access channel number 2 of c frame, the frequency position is different from the previously transmitted frequency position. Random access preamble is transmitted. In FIG. 10, since the random access channel number 1 of the c frame is selected, the antenna 2 is switched to transmit the random access preamble. On the other hand, in FIG. 11, since the random access channel number 3 of the b frame is selected, the random access preamble is transmitted with the antenna 1 as it is.

  FIG. 12 is a block diagram illustrating a schematic configuration of the mobile station apparatus according to the second embodiment. The mobile station apparatus 120 includes a data control unit 121, a DFT-S-OFDM (DFT-Spread-OFDM) modulation unit 122, a scheduling unit 123, an OFDM demodulation unit 124, a channel estimation unit 126, a control data extraction unit 127, and a synchronization correction unit. 128, a preamble generation unit 129, a signature selection unit 130, a radio unit 131, and an antenna switching unit 132 having an antenna 132a (antenna 1) and an antenna 132b (antenna 2). The scheduling unit 123 includes a UL scheduling unit 123a, a control data analysis unit 123b, a control data creation unit 123c, and a RACH calculation unit 123d. The scheduling unit 123 constitutes a control unit, and the radio unit 131 constitutes a transmission unit.

  User data and control data are input to the data control unit 121. The data control unit 121 is arranged to transmit user data and control data on the uplink shared channel PUSCH and the uplink control channel PUCCH according to an instruction from the scheduling unit 123. Also, an uplink pilot channel UPiCH is arranged. The DFT-S-OFDM modulation unit 122 performs data modulation, performs DFT-S-OFDM signal processing such as DFT conversion, subcarrier mapping, IFFT conversion, CP (Cyclic Prefix) insertion, filtering, etc., and DFT-Spread-OFDM signal Is generated. The uplink communication scheme is assumed to be a single carrier scheme such as DFT-Spred-OFDM, but may be a multicarrier scheme such as the OFDM scheme.

  The synchronization correction unit 128 corrects the transmission timing from the synchronization information input from the control data extraction unit 127 and outputs data modulated to match the transmission timing to the radio unit 131. Radio section 131 sets a frequency to be used for a predetermined radio frequency, up-converts the modulated data to a radio frequency, and transmits the radio data to the base station apparatus. Radio section 131 receives downlink data from the base station apparatus, down-converts it into a baseband signal, and outputs the received data to OFDM demodulation section 124.

  Channel estimation section 126 estimates the radio channel characteristics from downlink pilot channel DPiCH and outputs the estimation result to OFDM demodulation section 124. Further, in order to notify the base station apparatus of the radio propagation path estimation result, the estimated radio propagation characteristics are converted into CQI information, and the CQI information is output to the scheduling unit 123. The OFDM demodulator 124 demodulates the received data from the radio channel estimation result of the channel estimator 126. The control data extraction unit 127 separates the received data into user data and control data. Among the control data, uplink synchronization information is output to the synchronization correction unit 128, scheduling information and other layer 2 control data are output to the scheduling unit 123, and layer 3 control data and user data are output to the upper layer. .

  The signature selection unit 130 selects a signature ID number used in random access according to an instruction from the scheduling unit 123, and outputs the selected signature ID number to the preamble generation unit 129. The preamble generation unit 129 generates a random access preamble including a signature corresponding to the signature ID number selected by the signature selection unit 130, and outputs the random access preamble to the DFT-S-OFDM modulation unit 122.

  In the scheduling unit 123, the control data analysis unit 123b analyzes the control information input from the control data extraction unit 127, outputs the scheduling information to the UL scheduling unit 123a, and determines the synchronization timing included in the random access response or the synchronization information. Information is output to the synchronization correction unit 128. In addition, the control data analysis unit 123b outputs a broadcast information message including information on random access transmission such as information indicating the configuration of the random access channel and the transmission status of random access to the signature selection unit 130 and the RACH calculation unit 123d. In addition, the control data creation unit 123c is instructed to return ACK. The control data creation unit 123 c creates ACK / NACK and other control data and outputs them to the data control unit 121.

  The UL scheduling unit 123a instructs the data control unit 121 to map data and control information to each uplink channel based on scheduling information input from an upper layer and control information from the control data analysis unit 123b. . The RACH calculation unit 123d selects the position (frequency position, time position, etc.) of the random access channel RACH from the notified random access transmission-related information and the retransmission status (frequency position transmitted last time, antenna transmitted last time, number of retransmissions, etc.). To do. Also, a random access channel to be used at the time of retransmission of random access is selected. If the random access channel selected at the time of retransmission is the same frequency position as the previous random access preamble transmission, select an antenna different from the previous random access preamble transmission and switch the antenna to the antenna switching unit to switch the antenna. Instruct.

  In addition, the scheduling unit 123 instructs the signature selection unit 130 to perform random access according to an instruction from the upper layer. The antenna switching unit 132 switches the antenna to be used according to an instruction from the scheduling unit 123.

  Note that the configuration of the base station apparatus according to the present embodiment is the same as that of the first embodiment, and a description thereof will be omitted.

  FIG. 13 is a flowchart showing an operation example of the mobile station apparatus according to the second embodiment. First, the mobile station apparatus acquires information on random access broadcast from the base station apparatus (step R1), and resets the number of random access transmissions (step R2). Then, the random access channel selection process starts. In the random access channel selection process, it is determined whether or not the transmission is an initial transmission (step R3). If the transmission is an initial transmission, the random time nearest from the configuration of the random access channel in the acquired random access information is determined. Select an access channel.

  In step R3, in the case of retransmission, the time position of the random access channel closest in time is confirmed. It is confirmed whether the frequency position of this random access channel is a random access channel having the same frequency position as the frequency position of the previously transmitted random access channel. If the frequency position is the same, the transmission antenna is switched and the random access transmission process is started (step R4). In the case of a different frequency position, the same transmission antenna as the previous time is used, and the random access transmission process is started (step R4).

  In the random access transmission process, a signature to be included in the random access preamble is selected (step R5), a random access preamble is generated, and the random access preamble is transmitted through the selected random access channel (step R6). After transmitting the random access preamble, the random access response is received.

  In the random access response reception process, it is determined whether or not a random access response including the signature ID number of the random access preamble transmitted during the random access response reception period has been received (step R7). Perform processing. In the retransmission preparation process, it is determined whether or not the maximum number of random access transmissions (the maximum number of random access preambles including retransmissions performed in one random access) has been exceeded (step R8). Notifies the upper layer (step R9) and terminates the random access.

  If the maximum number of random access transmissions has not been exceeded in step R8, the number of random access transmissions is counted up (step R10). Next, it is determined whether or not the random access load is high (step R11). If the random access load is high, a random access channel time position within a certain range is selected at random, and the process waits until the selected time position (step R11). R12). Then, the process proceeds to step R3 to perform a random access channel selection process. If the random access load is low in step R11, the process proceeds to step R3, and a random access channel selection process is performed.

  In step R7, when the random access response including the signature ID number of the random access preamble transmitted by the mobile station apparatus is received within the random access response reception period, the L2 / L3 message transmission process is executed. That is, before transmission of the L2 / L3 message, the uplink transmission timing is corrected from the synchronization timing shift information included in the random access response (step R13). An L2 / L3 message is created (step R14), and the L2 / L3 message is transmitted to the base station apparatus (step R15). A response to the L2 / L3 message is confirmed from the base station apparatus, and it is determined whether or not the transmission of the L2 / L3 message is successful (step R16). When the transmission of the L2 / L3 message is successful, the contention resolution message reception period is waited for the contention resolution message from the base station apparatus. It is determined whether or not a contention resolution message has been received (step R17). If a contention resolution message has been received, random access is terminated.

  If transmission of the L2 / L3 message fails in step R16, the process proceeds to step R8 to perform retransmission preparation processing. If no contention resolution message is received in step R17, the process proceeds to step R8 to perform retransmission preparation processing.

  As described above, according to the second embodiment, antenna hopping can be performed, and retransmission having an antenna diversity effect can be performed.

It is a figure which shows the mode of resending of random access preamble when random access load is low. It is a figure which shows the mode of resending of random access preamble when a random access load is high. It is a figure which shows the mode of resending of random access preamble when a random access load is high. It is a block diagram which shows schematic structure of the base station apparatus which concerns on 1st Embodiment. It is a block diagram which shows schematic structure of the mobile station apparatus which concerns on 1st Embodiment. 3 is a flowchart illustrating an operation example of the mobile station apparatus according to the first embodiment. 6 is a flowchart showing another example of operation of the mobile station apparatus according to the first embodiment. It is a figure which shows the mode of resending of random access preamble when random access load is low. It is a figure which shows the mode of resending of random access preamble when random access load is low. It is a figure which shows the mode of resending of random access preamble when a random access load is high. It is a figure which shows the mode of resending of random access preamble when a random access load is high. It is a block diagram which shows schematic structure of the mobile station apparatus which concerns on 2nd Embodiment. 6 is a flowchart illustrating an operation example of the mobile station apparatus according to the second embodiment. It is a figure which shows the structure of the channel of EUTRA downlink and an uplink. It is a figure which shows the structural example of an uplink. It is a figure which shows the structural example of a random access channel. It is a figure which shows the example of the procedure of Contented based Random Access. It is a figure which shows the example of the procedure of Non-contented based Random Access.

Explanation of symbols

40 base station apparatus 41 data control unit 42 OFDM modulation unit 43 scheduling unit 43a DL scheduling unit 43b UL scheduling unit 43c control data creation unit 44 channel estimation unit 46 DFT-S-OFDM demodulation unit 47 control data extraction unit 48 preamble detection unit 49 Synchronization timing measurement unit 50 Radio unit 51 Data control unit 52 DFT-S-OFDM modulation unit 53 Scheduling unit 53a UL scheduling unit 53b Control data analysis unit 53c Control data creation unit 53d RACH calculation unit 54 OFDM demodulation unit 56 Channel estimation unit 55 Movement Station device 57 Control data extraction unit 58 Synchronization correction unit 59 Preamble generation unit 60 Signature selection unit 61 Radio unit 120 Mobile station device 121 Data control unit 122 DFT-S-OFDM modulation unit 123 Turing unit 123a UL scheduling unit 123b Control data analysis unit 123c Control data creation unit 123d RACH calculation unit 124 OFDM demodulation unit 126 Channel estimation unit 127 Control data extraction unit 128 Synchronization correction unit 129 Preamble generation unit 130 Signature selection unit 131 Radio unit 132 Antenna Switching unit 132a Antenna 132b Antenna

Claims (8)

Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A mobile station apparatus applied to a radio communication system that transmits a preamble,
When retransmission of a random access preamble for the base station device occurs, a control unit that selects a random access channel of a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble;
And a transmitter that retransmits a random access preamble using the selected random access channel. When retransmission of the random access preamble to the base station device occurs, the control unit, when the frequency band of the latest random access channel is the same as the frequency band of the random access channel used at the time of the previous transmission of the random access preamble, Holds retransmission of the random access preamble, selects a random access channel that is a subsequent random access channel and a frequency band different from the frequency band of the random access channel that was used at the time of the previous transmission of the random access preamble,
The mobile station apparatus according to claim 1, wherein the transmission section retransmits a random access preamble using the selected random access channel. When retransmission of a random access preamble to the base station apparatus occurs, the control unit selects a plurality of random access channels within a certain period as selection candidates, and transmits a random access preamble from the selection candidate random access channel last time. Select a random access channel with a frequency band different from the frequency band of the used random access channel,
The mobile station apparatus according to claim 1, wherein the transmission section retransmits a random access preamble using the selected random access channel. Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A mobile station apparatus applied to a radio communication system that transmits a preamble,
Multiple transmit antennas,
When retransmission of the random access preamble to the base station apparatus occurs, if the frequency band of the latest random access channel is the same as the frequency band of the random access channel used when transmitting the previous random access preamble, the random access preamble of the previous random access preamble While selecting a transmission antenna that is different from the transmission antenna used for transmission, if the frequency band of the most recent random access channel is different from the frequency band of the random access channel used during transmission of the previous random access preamble, the previous random access preamble A control unit that selects the same transmission antenna as the transmission antenna used when transmitting
A mobile station apparatus comprising: a transmitter that retransmits a random access preamble using the nearest random access channel with the selected transmission antenna. Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A mobile station apparatus applied to a radio communication system for transmitting a preamble,
Multiple transmit antennas,
When retransmission of the random access preamble to the base station apparatus occurs, a plurality of random access channels within a certain period are selected as candidates, and the random access channel used at the time of transmission of the random access preamble last time from the random access channel of the selection candidate When selecting a random access channel of a frequency band different from the frequency band of the selected random access channel, the same transmission antenna as the transmission antenna used at the time of transmission of the previous random access preamble is selected, while the random access channel of the selection candidate is used for the previous random access channel. When selecting a random access channel that has the same frequency band as the random access channel that was used when transmitting the preamble, the transmission address that was used when the previous random access preamble was transmitted is selected. A control unit for selecting a different transmit antenna from the antenna,
A mobile station apparatus comprising: a transmission unit that retransmits a random access preamble using the selected random access channel with the selected transmission antenna. Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A base station apparatus applied to a radio communication system that transmits a preamble,
A base station side receiving unit for receiving a random access preamble from the mobile station device according to any one of claims 1 to 5;
Based on the received random access preamble, a calculation unit that calculates a retransmission time interval when the mobile station apparatus retransmits the random access preamble;
A base station apparatus comprising: a base station side transmitter that transmits information indicating the calculated retransmission time interval to the mobile station apparatus. Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A wireless communication system for transmitting a preamble,
The mobile station apparatus according to any one of claims 1 to 5,
A radio communication system comprising the base station apparatus according to claim 6. Any one frequency band on the frequency axis is allocated to the random access channel and arranged on the time axis at a fixed time interval, and the mobile station device randomly accesses the base station device using any random access channel. A retransmission method of a random access preamble for transmitting a preamble,
In the mobile station device, when retransmission of the random access preamble to the base station device occurs, select a random access channel of a frequency band different from the frequency band of the random access channel used at the time of transmission of the previous random access preamble,
A random access preamble retransmission method, wherein the random access preamble is retransmitted using the selected random access channel.

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