JP2008124832A - Base station device, mobile station, radio communication system, cell search method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system in which system frequency bandwidth is 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz or 20 MHz, for instance, wherein the system frequency bandwidth of a base station device is reliably detected upon initial cell search. <P>SOLUTION: A synchronous channel signal is extracted from a reception signal, a synchronous sequence index is identified based on the synchronous channel signal, and an identifier indicating the system frequency bandwidth is detected from a cell inherent information index corresponding to the synchronous sequence index is detected to carry out the initial cell search. Also, in the case the identifier is detected, a non-initial cell search is carried out based on the synchronous channel signal not having the identifier mapped to a central frequency bandwidth of each bandwidth when the system frequency bandwidth corresponding to the identifier is divided by the maximum reception frequency bandwidth thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a base station apparatus, a mobile station apparatus, a radio communication system, a cell search method, and a program that can use a plurality of different system frequency bandwidths.

  In 3GPP (3rd Generation Partnership Project), a W-CDMA (Wideband Code Division Multiple Access) method is standardized as a third generation wireless access method (3G) of cellular mobile communication, and a service is started. Further, 3G evolution (Evolved Universal Terrestrial Radio Access, hereinafter referred to as “EUTRA”) and 3G network evolution (Evolved Universal Terrestrial Radio Access Network, hereinafter referred to as “European TR”, referred to as “U”, hereinafter referred to as “U”, referred to as “U”). . In addition, as a radio link from the base station apparatus to the mobile station apparatus (hereinafter referred to as “downlink”, a radio link from the mobile station apparatus to the base station apparatus is referred to as “uplink”), OFDM ( An Orthogonal Frequency Division Multiplexing method has been proposed.

  As the EUTRA technology, a technology such as an adaptive modulation and coding scheme (AMCS) based on adaptive radio link control (link adaptation) such as channel coding is applied to the OFDM scheme. For downlink radio channel arrangement in the OFDM scheme, time division multiplexing TDM (frequency division multiplexing), frequency division multiplexing FDM (frequency division division) using radio resources of the OFDM frequency axis (subcarrier) and time axis (OFDM symbol). Multiplexing) or a method of multiplexing in time and frequency by a combination of TDM and FDM has been proposed. Non-Patent Document 1 proposes a downlink radio frame configuration and a radio channel arrangement method.

  FIG. 13 is a diagram illustrating an example of a downlink radio frame configuration and radio channel arrangement of EUTRA assumed based on the proposal of 3GPP. The downlink radio frame is configured by a plurality of two-dimensional radio resource blocks (RBs) including a frequency bandwidth Bch and a time-axis subframe in a group of a plurality of frequency-axis subcarriers.

  For example, on the frequency axis, the maximum transmission / reception frequency bandwidth BW (hereinafter referred to as “system frequency bandwidth”) of the base station apparatus is 20 MHz, the RB frequency bandwidth Bch is 180 kHz, the subframe is 1.0 ms, and the subframe is 1.0 ms. When the carrier frequency bandwidth Bsc is set to 15 kHz and one radio frame is set to 10 ms, 1000 RBs are included in the downlink, 12 RBs are included in one RB, and the system frequency bandwidth is 20 MHz (effective The total frequency bandwidth (18 MHz) includes 1200 subcarriers. Ts represents the OFDM symbol length.

  As shown in FIG. 13, the common pilot channel CPICH (Common Pilot Channel) is arranged at the head of each subframe, and the broadcast channel BCH (Broadcast Channel) and the synchronization channel SCH (Synchronization Channel) are at the head of each radio frame. Is arranged. A plurality of synchronization channels SCH and broadcast channels BCH can be arranged in one radio frame (10 msec). The remaining part of each RB is used as a traffic channel TCH (Traffic Channel) and distributed to each mobile station apparatus using AMCS.

  The synchronization channel SCH is used for initial synchronization and cell search (including initial cell search and non-initial cell search) of OFDM received signals. The mobile station apparatus performs carrier frequency offset identification, OFDM symbol timing synchronization, radio frame timing synchronization, cell search, and the like using the synchronization channel SCH. The broadcast channel BCH includes base station device specific information, neighboring cell information, common control information transmitted to each mobile station device, and the like.

(1) Description of Synchronization Channel SCH As described above, the synchronization channel SCH inserted in the EUTRA downlink radio frame is used for initial synchronization of OFDM received signals, cell search, and the like. The synchronization channel SCH includes carrier frequency offset synchronization, OFDM symbol timing synchronization, radio frame timing synchronization, cell or sector specific physical layer index (c = 1, 2,..., C, hereinafter referred to as cell ID), and The direct / indirect information index associated with the cell ID is included. Further, the synchronization channel SCH includes cells such as the number of transmission antennas of the base station device, a broadcast channel frequency bandwidth that depends on the system frequency bandwidth unique to the base station device, the CP (Cyclic Prefix) length of the OFDM symbol, and radio frame timing. Or, a unique index related to the sector configuration is included.

  Here, the direct / indirect information index related to the cell ID and the unique index related to the cell or sector configuration are combined and defined as a cell specific information index (w = 1, 2,..., W). If the synchronization channel SCH does not have a unique index related to the cell or sector configuration, w corresponds to the direct / indirect information index related to the cell ID (c). Furthermore, when directly related to the cell ID (c), w = c or w and c can have a one-to-one correspondence.

  The configuration of the synchronization channel SCH includes initial synchronization characteristics such as carrier frequency offset and OFDM symbol timing detection accuracy, detection time, detection probability of a cell specific information index (w) (or synchronization sequence index (g), described later), and detection time. Cell search characteristics, system overhead (ratio of resources occupied by the synchronization channel SCH and overall radio frame resources), and the amount of calculation of signal processing in the mobile station apparatus. For example, the first synchronization channel can be expressed so that a large number of cell-specific information indexes (w) can be expressed with a small number of synchronization channel SCH resources while considering the improvement of initial synchronization characteristics, the improvement of cell search characteristics, and the processing amount of the mobile station apparatus. Various synchronization channel SCH configurations such as P-SCH, second synchronization channel S-SCH, and hierarchy / non-hierarchy have been proposed (see Non-Patent Document 1).

  The synchronization channel SCH (or the second synchronization channel S-SCH) has a synchronization sequence index (g = 1, 2,..., G) such as a GCL sequence having a different GCL (Generalized Chirp Like) sequence index in a cell or sector. ) And the synchronization sequence index (g = 1, 2,..., G) is associated with the cell-specific information index (w) (for example, g = w, or g and w are 1: 1). A method for detecting the cell specific information index (w) by detecting the synchronization sequence index (g) has been proposed (see Non-Patent Document 1).

(2) Explanation on Cell Search Procedure When the mobile station apparatus returns from outside the coverage when the power is turned on, an initial cell search ICS (Initial Cell Search) is performed to search for a cell to camp on, and when waiting for communication (idle mode). ), Or during communication (active mode), non-initial cell search NCS (also referred to as non-initial cell search) is required for neighbor cell measurement for cell reselection or handover. In the EUTRA system, a three-stage cell search procedure similar to the W-CDMA system has been proposed (see Non-Patent Document 1).

  FIG. 14 is a flowchart illustrating an example of a cell search procedure in the EUTRA system. In step 1 (R1, first stage), a carrier frequency offset corresponding to the maximum power synchronization channel SCH by the autocorrelation or cross-correlation processing in the time domain is applied to the received signals of the plurality of synchronization channels SCH, OFDM symbols Timing detection is performed. In step 2 (R2, second stage), the carrier frequency offset and OFDM symbol timing correction is performed based on the detection result, the OFDM signal is demodulated (CP removal, DFT conversion), and the synchronization sequence mapped to the synchronization channel SCH in the frequency domain The index (g) is detected, and the cell specific information index (w) is identified. When the cell ID (c) is directly included in the cell specific information index (w), the cell ID is identified.

  Indirect information of the cell ID (c) in the cell specific information index (w), for example, a scrambling group SG (Scramble Group) index (h = 1, 2,..., H, used in the W-CDMA system) If H = 64 in the case of the W-CDMA system is identified, a plurality of scrambling code SC (Scramble Code) indexes (scrambled group SG index (h)) (step 3 (R3, third stage)) ( s = 1, 2,..., S, S = 512 in the case of the W-CDMA system, for example, one scrambling group SG index (h) has eight scrambling code SC indexes (s ), The number of received reference signals RS is 8 times. The cell ID (c) (assuming that i = c is assumed here) is identified using the downlink reference signaling channel DRSCH with the maximum power.

  As a technical requirement of EUTRA / EUTRAN, spectrum flexibility is required for fusion and coexistence with existing 2G and 3G mobile communication services, and different system frequency bandwidths, for example, 1.25 MHz. Support for spectrum allocation of 5 MHz, 5 MHz, 10 MHz, and 20 MHz (Support for spectrum allocations of differential size) is required. In addition, it is required to support a mobile station apparatus having transmission / reception capabilities of different frequency bandwidths, for example, 10 MHz and 20 MHz mobile station apparatus capabilities (UE Capability) for different system frequency bandwidths (Non-Patent Document 2). reference).

  Further, since the base frequency of the base station apparatus RF (Radio Frequency) of the EUTRA / EUTRAN system is shared with the frequency spectrum of the existing W-CDMA system, the RF center frequency and channel number UARFCN used for W-CDMA (UTRA It is necessary to match the absolute radio frequency channel number (see Non-Patent Document 3), as shown in FIG. 15, the synchronization channel SCH and / or the broadcast channel BCH are divided into frequency rasters because of the frequency raster (200 kHz) relationship. In order to meet the above requirements, there is a method in which a part of the system frequency bandwidth, for example, 1.25 MHz is arranged around the base station apparatus RF center frequency (see Non-Patent Document 1) .

  In addition, when the frequency bandwidth (mobile station device capability) owned by the mobile station device is smaller than the system frequency bandwidth, the frequency band position to be used during the initial cell search and standby cell search, and during the cell search during communication A method of designation (center frequency shift) is shown (see Non-Patent Document 1). This will be described with reference to FIG. For example, when the system frequency bandwidth is 20 MHz and the mobile station apparatus capability is 10 MHz, the mobile station apparatus is powered on, and first performs an initial cell search at intervals of W-CDMA channel number UARFCN (frequency raster: 200 KHz). (Including band search). In the initial cell search, by receiving the power of the synchronization channel SCH of 1.25 MHz, the effective cell signal of the center 1.25 MHz of the system frequency bandwidth is detected, and the synchronization channel SCH is received. Thereafter, the broadcast channel BCH is received.

  The broadcast channel BCH includes system frequency bandwidth information and frequency shift information for designating a frequency band position to be used by each mobile station apparatus having different mobile station apparatus capabilities. When the mobile station apparatus in standby (idle mode) shifts to communication (active mode), the mobile station apparatus moves to the use frequency band position according to the control information and starts packet data communication.

  On the other hand, as shown in FIG. 17, for the base station apparatus having the 20 MHz system frequency bandwidth, the base station apparatus RF center frequency, that is, the center frequency of the 20 MHz system frequency bandwidth, the upper 10 MHz bandwidth, There is a method in which three 1.25 MHz synchronization channels SCH and broadcast channel BCH are arranged in accordance with the center frequency and the center frequency of the lower 10 MHz bandwidth (see Non-Patent Document 4).

  In this method, an initial cell search by the base station apparatus RF center frequency, a non-initial cell search, that is, a cell search during standby (idle mode), and a center frequency of the upper / lower 10 MHz bandwidth (which does not match the channel number UARFCN) A cell search can be performed during communication (active mode). The mobile station device in the active mode needs to perform a cell search during communication of neighboring cells at the time of handover. The mobile station device in the idle mode needs to perform a standby cell search for the serving cell and the neighboring cell when updating the paging information and broadcast information.

  FIG. 18 is a diagram illustrating the center frequency when the system frequency band of the base station apparatus is 20 MHz, and the 10 MHz frequency band used by the mobile station apparatus in the system frequency band. As shown in FIG. 18, the center frequency of the usage frequency band of the mobile station apparatus may be slightly shifted depending on how the guard band is set in the usage frequency band of the mobile station apparatus.

FIGS. 19 to 23 are diagrams illustrating the configuration of the synchronization channel SCH. For example, the number of transmission antennas of the base station apparatus, the broadcast channel frequency bandwidth, the CP length of the OFDM symbol, and the radio frame timing are each set to two states. The cell configuration ID total number (W) is 16 (4 bits). If the system frequency bandwidth of the base station apparatus is 20 MHz, the total number of subcarriers is 1201, the central subcarrier is excluded, and the subcarrier interval of the reference signal RS is 6, as shown in FIG. When the mapped synchronization sequence length (for example, the length of the GCL sequence) is 72 subcarriers (synchronization channel bandwidth 1.25 MHz = 6 RBs), the sector-specific physical layer index total number (C) according to equation (1) Is 840, that is, 840 sectors can be identified.
C = int (S / W) U (1)
Here, C is the total number of cell IDs (c), U is the total number of reference signal RS sequence indexes, W is the total number of cell configuration IDs (w), and S is the synchronization sequence index (s) mapped to the synchronization channel SCH. Indicates the total number.

Also, the synchronization channel can adopt the configuration shown in FIGS. In FIG. 20, synchronization channels are arranged every other subcarrier with respect to FIG. 19. In FIG. 21, the synchronization channel P-SCH and the synchronization channel S-SCH are alternately arranged. In FIG. 22, the synchronization channel P-SCH and the synchronization channel S-SCH are alternately arranged every other subcarrier. In FIG. 23, the first synchronization channel and the second synchronization channel are arranged in the time axis direction. Other combinations of synchronization channel configurations are also envisioned.
3GPP TR (Technical Report) 25.814, Physical Layer Aspects for Evolved UTRA. http: // www. 3 gpp. org / ftp / Specs / html-info / 25814. htm 3GPP TR (Technical Report) 25.913, Requirements for evolved Universal Terrestrial Radio Access (UTRA) and Universal Terrestrial Radio Acces. http: // www. 3 gpp. org / ftp / Specs / html-info / 25913. htm 3GPP TS 25.101, V6.8.0 (2005-06), User Equipment (UE) radio transmission and reception (FDD), http: // www. 3 gpp. org / ftp / Specs / html-info / 25-series. htm R1-062217, Samsung, SCH structure concealing EUTRA spectrum allocation, 3GPP TSG RAN WG1 Meeting # 46, Tallinn, Estonia, Aug. 28-Sept. 1, 2006 http: // www. 3 gpp. org / ftp / tsg_ran / WG1_RL1 / TSGR1_46 / Docs /

  However, the initial cell search by the base station apparatus RF center frequency and the non-initial cell search, that is, the waiting cell search, and the in-communication cell search by the center frequency of the upper / lower 10 MHz bandwidth (which does not match the channel number UARFCN) are performed. If this is done, three pieces of broadcast information necessary for cell search must also be arranged. However, if the non-initial cell search is configured to be performed at the upper / lower 10 MHz, broadcast information of the base station apparatus RF center frequency is not necessary. That is, if the non-initial cell search is performed in another frequency band, unnecessary radio resources are used.

  On the other hand, since the system frequency bandwidth of the base station apparatus varies from 1.25 MHz to 20 MHz, the initial cell search procedure needs to be unified without depending on the system frequency bandwidth. Furthermore, the system frequency bandwidth of the base station apparatus is included in the broadcast information, and when the broadcast information cannot be acquired at the initial cell search, it is impossible to acquire the system frequency bandwidth information.

  Also, at the time of initial cell search of a system frequency bandwidth other than 20 MHz, the mobile station device needs to acquire broadcast information at the RF center frequency of the base station device. Therefore, at the initial cell search of the system frequency bandwidth of 20 MHz, it is necessary to be able to detect that the mobile station apparatus is a system of at least 20 MHz frequency bandwidth.

  The present invention has been made in view of such circumstances, and in a system whose system frequency bandwidth is, for example, 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, or 20 MHz, a base station apparatus at the time of initial cell search An object of the present invention is to provide a base station device, a mobile station device, a radio communication system, a cell search method, and a program capable of reliably detecting the system frequency bandwidth of the system.

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the base station apparatus of the present invention is a base station apparatus applied to a radio communication system that uses a plurality of different system frequency bandwidths, and is provided with an identifier-attached synchronization channel signal having an identifier indicating the system frequency bandwidth. And a channel mapping unit that maps the identifier-attached synchronization channel signal to a center frequency band of the system frequency bandwidth.

  In this way, since the synchronization channel signal with an identifier having an identifier indicating the system frequency bandwidth is mapped to the center frequency band of the system frequency bandwidth, the mobile station apparatus having a different frequency bandwidth to be used is By receiving the synchronization channel (SCH2) in the center frequency band, it is possible to reliably grasp the system frequency bandwidth.

  (2) Moreover, in the base station apparatus of the present invention, the control signal generation unit generates a synchronization channel signal not having the identifier, and the channel mapping unit moves the system frequency bandwidth to a communication partner. A synchronization channel signal not having the identifier is mapped to a center frequency band of each bandwidth when divided for each maximum reception frequency bandwidth of the station apparatus.

  Thus, the synchronization channel signal having no identifier is mapped to the center frequency band of each bandwidth when the system frequency bandwidth is divided for each maximum reception frequency bandwidth of the mobile station apparatus that is the communication partner. The mobile station apparatuses using different frequency bandwidths can reliably perform the non-initial cell search by receiving the synchronization channel (SCH1) in the center frequency band during the non-initial cell search.

  (3) Moreover, in the base station apparatus of the present invention, a part of the cell specific information index included in the synchronization channel signal is the identifier.

  Thus, since a part of the cell specific information index is the identifier, the total number of cell IDs (c) is not drastically reduced due to the identifier indicating the system frequency band. Can be secured sufficiently.

  (4) Further, the mobile station apparatus of the present invention is a mobile station apparatus applied to a radio communication system using a plurality of different system frequency bandwidths, and extracts a control signal from a received signal. A cell search unit for performing an initial cell search for identifying a synchronization sequence index based on the synchronization channel signal and detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index; It is characterized by providing.

  Thus, when performing the initial cell search, the identifier indicating the system frequency bandwidth is detected from the cell specific information index, so that the system frequency band can be ascertained reliably.

  (5) In the mobile station apparatus of the present invention, when the cell search unit detects the identifier, the system frequency bandwidth corresponding to the identifier is divided for each maximum reception frequency bandwidth of itself. A non-initial cell search is performed based on a synchronization channel signal that does not have the identifier mapped to the center frequency band of each bandwidth.

  Thus, when the identifier is recognized in the initial cell search, the mobile station apparatus can perform a frequency shift and perform a non-initial cell search based on the broadcast channel in its own maximum reception frequency band. As a result, it is possible to reliably recognize the system frequency bandwidth even for mobile station apparatuses having different frequency bands, so that it is not necessary to map the broadcast channel to the center frequency of the system frequency bandwidth, and radio resources are effectively used. It can be used.

  (6) Moreover, the radio | wireless communications system of this invention is comprised from the base station apparatus in any one of Claims 1-3, and the mobile station apparatus of Claim 4 or Claim 5. It is characterized by.

  According to this configuration, since the synchronization channel signal with an identifier having an identifier indicating the system frequency bandwidth is mapped to the center frequency band of the system frequency bandwidth, the mobile station apparatus using a different frequency bandwidth can perform the initial cell search. Sometimes, by receiving the synchronization channel (SCH2) in the center frequency band, it is possible to reliably grasp the system frequency bandwidth.

  (7) The cell search method of the present invention is a cell search method for a mobile station apparatus applied to a radio communication system using a plurality of different system frequency bandwidths, and extracts a synchronization channel signal from a received signal. A step of identifying a synchronization sequence index based on the synchronization channel signal, and an initial cell search by detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index And when the identifier is detected, the identifier mapped to the center frequency band of each bandwidth when the system frequency bandwidth corresponding to the identifier is divided for each maximum reception frequency bandwidth of the identifier. Step for performing non-initial cell search based on synchronization channel signal not possessed Is characterized in that it comprises the, at least.

  In this way, since the synchronization channel signal with an identifier having an identifier indicating the system frequency bandwidth is mapped to the center frequency band of the system frequency bandwidth, the mobile station apparatus having a different frequency bandwidth to be used is By receiving the synchronization channel (SCH2) in the center frequency band, it is possible to reliably grasp the system frequency bandwidth.

  (8) A program according to the present invention is a program for controlling a cell search operation of a mobile station apparatus applied to a radio communication system using a plurality of different system frequency bandwidths, from a received signal to a synchronization channel signal. , A process of identifying a synchronization sequence index based on the synchronization channel signal, and an initial cell search by detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index When the identifier is detected, the system frequency bandwidth corresponding to the identifier is mapped to the center frequency band of each bandwidth when divided for each maximum reception frequency bandwidth. A process for performing a non-initial cell search based on a synchronization channel signal having no identifier. When, a series of processes including, is characterized by being configured as instructions a computer can execute.

  In this way, since the synchronization channel signal with an identifier having an identifier indicating the system frequency bandwidth is mapped to the center frequency band of the system frequency bandwidth, the mobile station apparatus having a different frequency bandwidth to be used is By receiving the synchronization channel (SCH2) in the center frequency band, it is possible to reliably grasp the system frequency bandwidth.

  According to the present invention, in a system having a system frequency bandwidth (for example, 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz, and 20 MHz), the system frequency bandwidth of the base station apparatus can be reliably detected during the initial cell search. It becomes possible.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram for explaining an example of the physical channel configuration of EUTRA. FIG. 1 shows an example of an “uplink / downlink” physical channel configuration assumed for EUTRA based on the proposal of 3GPP.

EUTRA downlink physical channels include the following types of channels. That is,
(1) Downlink Reference Signaling Channel (DRSCH) (Downlink Reference Signaling Channel),
(2) Downlink synchronization channel SCH (Downlink Synchronization Channel),
(3) Downlink broadcast channel BCH (Downlink Broadcast Channel),
(4-1) Downlink shared control signaling channel DSSCH (Downlink Shared Control Signaling Channel), and
(4-2) A downlink shared data channel DSDCH (Downlink Shared Data Channel).

With the above (4-1) downlink shared control signaling channel DSCSCH and downlink shared data channel DSDCH,
(4) A downlink scheduling channel DSCH (Downlink Scheduling Channel) is configured.

In addition, as the uplink physical channel of EUTRA, there are the following types of channels. That is,
(1) Uplink Contention-based Channel UCBCH (Uplink Contention-based Channel),
(2) Uplink scheduling channel USCH (Uplink Scheduling Channel),
(3) Uplink reference signaling channel URSCH (Uplink Reference Signaling Channel).

  FIG. 2 is a diagram illustrating an arrangement example of the downlink synchronization channel SCH according to this embodiment in which the system frequency bandwidth is 20 MHz. As in the case shown in FIG. 17, the synchronization channel SCH includes the base station apparatus RF center frequency, that is, the center frequency (SCH2) of the 20 MHz system frequency bandwidth, the center frequency (SCH1) of the upper 10 MHz bandwidth, and the lower 10 MHz. Three synchronization channels SCH are arranged in accordance with the center frequency (SCH1) of the bandwidth. As an example, the frequency bandwidth of the synchronization channel SCH is 1.25 MHz.

  However, unlike the case shown in FIG. 17, in FIG. 2, two broadcast channels BCH are arranged according to the center frequency of the upper 10 MHz bandwidth and the center frequency of the lower 10 MHz bandwidth, and It is not placed at the RF center frequency. Here, in order to clarify the problem in the frequency direction, in FIG. 2, the concept in the time direction is removed. Of course, the synchronization channel SCH, broadcast channel BCH, and normal data channel are also multiplexed in the time direction. In this case, the initial cell search by the base station apparatus RF center frequency and the non-initial cell search by the center frequency of the upper / lower 10 MHz bandwidth (which does not match the channel number UARFCN), that is, the standby cell search and the in-communication cell search are performed. Can do.

  Here, the initial cell search means that a mobile station apparatus (such as when the power is turned on) that is not yet connected to the network performs a band search at an interval of channel number UARFCN (200 kHz) to detect a synchronization channel SCH, that is, a synchronization sequence. The index (g) is detected, and the cell specific information index (w) for identifying the cell ID (c) is obtained from the synchronization sequence index (g). Further, the cell search during communication means that the active mode mobile station apparatus detects a synchronization channel SCH of an adjacent cell, compares the characteristics with the serving cell (currently communicating cell), and determines the handover. . The standby cell search means that the idle mode mobile station apparatus detects the synchronization channel SCH of the serving cell (currently standby cell) and the synchronization channel SCH of the adjacent cell when paging information or broadcast information is updated. . Since the mobile station apparatus performs the standby operation in the upper / lower 10 MHz band, it is not necessary to arrange the broadcast channel BCH at the base station apparatus RF center frequency.

  However, as shown in FIG. 2, during the initial cell search, unlike the base station apparatus having a specific system frequency bandwidth equal to or lower than the 10 MHz system frequency bandwidth, the broadcast channel BCH does not exist at the base station apparatus RF center frequency. The mobile station apparatus fails to acquire the broadcast channel BCH after the initial cell search. That is, in the case of a base station apparatus having a 20 MHz system frequency bandwidth, it has a system frequency bandwidth of 20 MHz or less, for example, a system frequency bandwidth of 10 MHz, 5 MHz, 2.5 MHz, or 1.25 MHz as shown in FIG. Unlike the base station apparatus, the mobile station apparatus normally cannot know information on the system frequency bandwidth of the base station apparatus included in the broadcast channel BCH. If the mobile station device cannot know the specific system frequency bandwidth of the base station device, it cannot acquire the broadcast channel BCH arranged in the upper / lower 10 MHz band of 20 MHz.

  Therefore, in the present embodiment, the system frequency bandwidth information is included in the synchronization channel SCH of the base station apparatus RF center frequency used for the initial cell search of the base station apparatus having the 20 MHz system frequency bandwidth. Note that the physical structure of the synchronization channel SCH adopts the same structure as the conventional one.

  Various configurations have been conventionally proposed as the synchronization channel SCH. In the present embodiment, attention is paid to the synchronization sequence index (g) arranged in the synchronization channel SCH regardless of the structure of the synchronization channel SCH and the configuration of the synchronization sequence. is doing. The length of the synchronization sequence that can be arranged is determined by the structure of the synchronization channel SCH, and the type of synchronization sequence, that is, the number of synchronization sequence numbers that can be expressed by the synchronization sequence pattern, that is, the total number (G) of synchronization sequence indexes can be determined. . The synchronization sequence index (g) has a one-to-one correspondence with the cell specific information index (w), and the cell specific information index (w) is identified by identifying the synchronization channel SCH, that is, identifying the synchronization sequence index (g). And the unique information of the cell configuration such as the cell ID can be identified.

  As described above, the synchronization channel SCH includes the cell ID (c), the direct / indirect information index related to the cell ID (c), the number of transmission antennas of the base station apparatus, and the system frequency bandwidth specific to the base station apparatus. And a unique index related to a cell or sector configuration, such as a broadcast channel frequency bandwidth, a CP (Cyclic Prefix) length of an OFDM symbol, and a radio frame timing. Here, the cell unique information index (w) is defined by combining the direct / indirect information index related to the cell ID (c) and the unique index related to the cell or sector configuration.

  In order to easily explain the present invention, as an example, only the cell ID (c) is associated with the cell specific information index (w). For example, there is a case where the cell specific information index (w) and the cell ID (c) have a one-to-one correspondence. In addition, in order not to impair generality, the cell specific information index (w) includes indirect information of the cell ID (c), for example, the scrambling group SG index (h), and / or cell specific configuration information, for example, It may include the number of transmission antennas of the base station apparatus or the broadcast channel frequency bandwidth depending on the system frequency bandwidth unique to the base station apparatus, the CP (Cyclic Prefix) length of the OFDM symbol, the radio frame timing, and the like.

  As one example, it is assumed that there are 512 types of cell ID (c) as employed in the W-CDMA system. That is, C = 512. There are 512 types of scrambling code SC index (h) corresponding to each cell, that is, H = 512.

  First, a cell ID (c), an identifier of a base station apparatus having a system frequency bandwidth of 10 MHz or less, and an identifier of a base station apparatus having a system frequency bandwidth of 10 MHz or less (hereinafter referred to as “20 MHz band identifier (y = 1, 2)” and Let's consider a method of expressing. In this case, for example, as shown in FIG. 4, if the total number (G) of synchronization sequence indexes arranged in the synchronization channel SCH is 512, the 20 MHz band identifier (y) needs 1 bit in two states. Therefore, the remaining synchronization sequence index (g) can express the cell unique information index (w), that is, the cell ID (c). That is, when the total number (G) of the synchronization sequence index is 512, it can represent a 1-bit 20 MHz band identifier (y) in two states and an 8-bit cell ID in 256 states. Here, as is apparent from FIG. 4, the cell ID (c) that can be expressed is halved.

  Therefore, as shown in FIG. 5, cell IDs (c) 1 to 511 are used as normal cell IDs, and cell ID 512 is a special ID for a 20 MHz frequency bandwidth system. That is, it is used as a 20 MHz band identifier (y). This 20 MHz band identifier (y) is arranged at the center frequency (matching the channel number UARFCN) of the 20 MHz system frequency bandwidth as the synchronization channel SCH2 for initial cell search. Therefore, in the initial cell search in the 20 MHz frequency bandwidth system, the mobile station apparatus does not acquire the cell ID (c) but only detects that the system frequency bandwidth is 20 MHz.

  On the other hand, the synchronization channel SCH1 for non-initial cell search is selected and arranged for each cell out of a total of 511 from cell ID (c = 1) to cell ID (c = 511). A base station apparatus having a system frequency bandwidth of 10 MHz or less uses a cell ID (c = 1) to a cell ID (c = 511) as the cell ID (c).

  As shown in FIG. 5, the cell specific information index (w) may include indirect information of the cell ID (c), for example, cell ID group information, and other cell specific configuration information such as the number of base station apparatus transmission antennas. One of the cell specific information indexes (w), for example, w = 512 may be used for the 20 MHz band identifier (y).

  Also, as shown in FIG. 6, the total number (G) of synchronization sequence indexes arranged in the synchronization channel SCH is 512, and the number of antennas is two. Since the number of antennas requires one bit in two states, the remaining synchronization sequence index (g) can express the cell specific information index (w), that is, the cell ID (c). That is, when the total number (G) of synchronization sequence indexes is 512, the number of 1-bit antennas in 2 states and the cell ID of 8 bits in 256 states can be represented. Then, as shown in FIG. 6, for each state of the number of antennas, cell IDs (c) # 1 to 255 are used as normal cell IDs, and cell ID # 256 is used as a frequency bandwidth of 20 MHz. It is used as a special ID for the system, that is, a 20 MHz band identifier (y). This 20 MHz band identifier (y) is arranged at the center frequency (matching the channel number UARFCN) of the 20 MHz system frequency bandwidth as the synchronization channel SCH2 for initial cell search. Therefore, in the initial cell search in the 20 MHz frequency bandwidth system, the mobile station apparatus does not acquire the cell ID (c) but only detects that the system frequency bandwidth is 20 MHz.

  Further, as shown in FIG. 7, the 256th cell ID in which the number of antennas is in either state may be used as the 20 MHz band identifier (y). In FIG. 7, the 256th cell ID (c) when the number of antennas is 2 is used as the 20 MHz band identifier (y). The 256th cell ID (c) when the number of antennas is 1 may be used as the 20 MHz band identifier (y).

  With such a configuration, all base station apparatuses having a 20 MHz system frequency bandwidth transmit the same synchronization channel SCH2 as a 20 MHz band identifier (y). Therefore, when transmission timing synchronization is obtained among a plurality of base station apparatuses, interference in the radio section is reduced, and it is possible to suppress transmission power for the synchronization channel SCH2 of the base station apparatus. In addition, during the initial cell search, different cell IDs (C) are not transmitted from other base station apparatuses to interfere with each other, leading to a reduction in cell search time. Actual cell identification, that is, identification of direct / indirect information of the cell ID (c) included in the cell-specific information index (w) is performed using the synchronization channel SCH1.

(A) Configuration of Transmission Unit of Base Station Device FIG. 8 is a block diagram showing a configuration of the transmission unit of the base station device (cell or sector) according to this embodiment. FIG. 8 shows a transmission unit of one sector. When one base station apparatus is configured by three sectors, three transmission units illustrated in FIG. 8 are provided. Further, in the case where a single sector includes a plurality of (1 to 4) transmission antennas, a plurality of (1 to 4) transmission units corresponding to the plurality of transmission antennas illustrated in FIG. 8 can be configured. . Here, as an example, a transmission unit in which one transmission antenna corresponds to one sector will be described.

  The transmission unit 10 includes a serial-parallel conversion (S / P) unit 11, a control signal generation unit 12, a channel mapping unit 13, an IDFT conversion unit (Inverse Discrete Fourier Transform) 14, a parallel-serial conversion unit (P / S) 15, CP (Cyclic Prefix) insertion unit 16, DAC processing unit (digital / analog signal conversion) 17, radio unit (TX) 18, and transmission antenna 19.

  The transmission data of each mobile station apparatus shown in FIG. 13 (for example, mobile station apparatuses MS1, 2, and 3 in FIG. 13) is input to the serial / parallel converter (S / P) 11, and after parallel data conversion, channel mapping is performed. Input to the unit 13. The channel mapping unit 13 uses the CQI measurement result fed back from the mobile station device (the channel estimation / output of the CQI measurement unit 30 of the receiving unit of the mobile station device shown in FIG. 10), and the radio propagation path of the mobile station device Adaptive modulation (AMCS) is performed to select a radio resource block RB suitable for the transmission, and transmission data is mapped to a predetermined RB. User data mapped to the traffic channel TCH generates an OFDM signal by the IDFT conversion unit 14, and passes through a parallel / serial conversion unit (P / S) 15, a CP insertion unit 16, and a DAC processing unit (digital / analog signal conversion) 17. , And input to the radio unit (TX) 18. In the radio unit (TX) 18, the signal is transmitted as a downlink signal by the transmission antenna 19 to the mobile station apparatus through the filtering process of the OFDM signal, the frequency conversion, and the like.

  On the other hand, a reference signal RS, a scrambling code SC signal (including a scrambling code SC index), a synchronization channel SCH signal (including a cell specific information index (w)), a broadcast channel BCH signal, shared by the control signal generator 12 A control signal such as an individual control signal is generated and input to the channel mapping unit 13. The channel mapping unit 13 maps each control signal to the common control channel as shown in FIG.

(1) Generation of Reference Signal RS Conventionally, various reference sequences and arrangement methods (mapping methods) between cells and sectors have been proposed as the reference signal RS. Here, as one example, the length of the reference sequence is defined by the system frequency bandwidth of the base station apparatus defined in advance, and an orthogonal reference sequence is used between the three sectors. The reference signal RS is a downlink channel estimation for downlink radio channel quality measurement (Downlink-channel-quality measurement) for applying AMCS technology, correlation demodulation or correlation detection in a mobile station apparatus. used for for coherent demodulation / detection at the UE). When the synchronization channel SCH includes indirect information of the cell ID (c), for example, the scrambling group SG index (h), it is also used for cell search.

(2) Generation of Scrambling Code SC Signal As a scrambling code SC signal, various sequences and arrangement methods (mapping methods) between cells and sectors have been proposed. As one example, the control signal generation unit 12 includes the length of the scrambling code SC specified from the control data, or the length of the scrambling code SC calculated from information such as the system frequency bandwidth of the base station apparatus, and the scrambling. The scrambling code SC index (s) calculated from the control data information such as the group SG index (h) is substituted into a predetermined scrambling code SC generation formula to generate a predetermined scrambling code SC and channel mapping To the unit 13. The channel mapping unit 13 maps the scrambling code SC as shown in FIG. 9 to each subcarrier (scrambling process). However, the scrambling process is not performed on the synchronization channel SCH signal.

(3) Generation of Synchronization Channel SCH Signal The control signal generation unit 12 generates a synchronization channel SCH signal based on the synchronization channel SCH generation information specified from the control data. The synchronization channel SCH generation information includes the system frequency bandwidth of the base station apparatus, the insertion position of the synchronization channel SCH signal in the radio frame, the number of repetitions, the first synchronization channel P-SCH, and the second synchronization channel S-SCH. Information such as physical signal configuration is included. In the present embodiment, the information is not limited, and a synchronization sequence index (g = 1, 2,...) That is one of synchronization-related specific information included in the synchronization channel SCH (P-SCH and S-SCH). , G).

  The control signal generation unit 12 is configured to provide cell information such as direct / indirect information of the cell ID (c) designated from the control data, the number of transmission antennas of the base station apparatus, the broadcast channel frequency bandwidth, the CP length of the OFDM symbol, and the radio frame timing. Alternatively, a cell-specific information index (w) including a sector structure-related unique index is calculated, and a synchronization sequence associated with w (for example, g = w or a one-to-one correspondence between g and w). The index (g) is determined. g is substituted into a predetermined synchronization sequence generation formula, a predetermined synchronization sequence is generated, and output to the channel mapping unit 13. When the system frequency bandwidth of the base station apparatus is 10 MHz or less, the channel mapping unit 13 generates a synchronization channel SCH of 1.25 MHz at the RF center frequency of the base station apparatus as shown in FIG.

  When the system frequency bandwidth of the base station apparatus is 20 MHz, as shown in FIG. 5, the generated synchronization sequence (for example, one of synchronization sequence indexes g = 1, 2,... 511, g = 2 Is output to the channel mapping unit 13. As shown in FIG. 2, the channel mapping unit 13 generates the synchronization channel SCH1 at the center frequency of the upper 10 MHz bandwidth and the center frequency of the lower 10 MHz bandwidth. Also, as shown in FIG. 5, a synchronization sequence corresponding to g = 512 representing a 20 MHz band identifier is generated and output to the channel mapping unit 13. As shown in FIG. 2, the channel mapping unit 13 generates a synchronization channel SCH2 of 1.25 MHz at the RF center frequency of the base station apparatus.

(4) Generation of broadcast channel BCH signal and shared / individual control signal The control signal generation unit 12 extracts broadcast information such as system-specific parameters and cell / sector-specific parameters from the control data, generates a broadcast channel BCH signal, Also, from the control data, individual control information such as a shared control signal required by the mobile station apparatus, a layer 1 / layer 2 control signal, a position of the RB assigned to the packet data addressed to the own station, and an AMCS parameter is extracted, and a shared / individual control signal is obtained. Is input to the channel mapping unit 13. The channel mapping unit 13 maps the generation of the broadcast channel BCH signal and the shared / dedicated control signal to the broadcast channel BCH and the common control channel as shown in FIG.

(B) Configuration of Receiving Unit of Mobile Station Device FIG. 10 is a block diagram showing a configuration of the receiving unit of the mobile station device according to this embodiment. When one sector is composed of a plurality of (1 to 4) transmitting antennas, the mobile station apparatus can be composed of a plurality (1 to 4) receiving units (branches) corresponding to the plurality of receiving antennas. . Here, as an example, a receiving unit (one receiving antenna branch) corresponding to one receiving antenna will be described. The receiving unit 20 of the mobile station apparatus includes a receiving antenna 21, a radio unit (RX) 22, an ADC (analog / digital signal conversion) processing unit 23, a CP deletion unit 24, a parallel / serial conversion unit (P / S) 25, a DFT. A conversion unit (Discrete Fourier Transform, Discrete Fourier Transform) 26, a channel demapping unit 27, a parallel-serial conversion unit (P / S) 28, a control signal extraction unit 29, a channel estimation / CQI measurement unit 30, and a cell search unit 31 are included. It is.

  The downlink radio signals transmitted from the plurality of sectors and the plurality of transmission antennas illustrated in FIG. 8 are combined at the end of the reception antenna 21 in FIG. 10 and are analogized such as filtering of the radio unit (RX) 22 and frequency conversion. / Digital signal conversion (ADC) is converted into a digital baseband signal. The CP deletion unit 24 deletes the CP part based on the OFDM symbol timing of the cell search result that is the output of the cell search unit 31 described later. The serial / parallel converter (S / P) performs serial / parallel conversion, and the DFT converter 26 performs OFDM signal demodulation. The channel demapping unit 27 demodulates the traffic channel TCH and the common control channel, the traffic channel TCH data is converted by the parallel / serial conversion unit (P / S) 28, and the packet data addressed to the own station is demodulated. The common control channel data is sent to the control signal extraction unit 29.

  On the other hand, based on the input signal from the channel demapping unit 27, the control signal extraction unit 29 is a control signal such as a synchronization channel SCH signal, a scrambling code SC signal, a reference signal RS, a broadcast channel BCH signal, and a shared / individual control signal. To extract.

(1) Extraction of synchronization channel SCH signal The operation of the mobile station apparatus is divided into an initial cell search and a non-initial cell search. In the case of the initial cell search, the radio unit (RX) 22 tunes to the RF center frequency of the base station apparatus and demodulates the OFDM signal. The control signal extraction unit 29 extracts the synchronization channel SCH signal (SCH 2 in the case of a 20 MHz system frequency band field) from the channel demapping unit 27 and outputs it to the cell search unit 31. The cell search unit 31 detects the carrier frequency offset of the received signal, detects and corrects the OFDM symbol timing, and identifies the synchronization sequence index (g).

  When the cell ID (c) is detected by the detected synchronization sequence index (g), that is, the cell unique information index (w), the cell search unit 31 detects the detected reference sequence index (for example, corresponding to three sectors). , R = 1, 2, 3) are output to the channel estimation / CQI measurement unit 30 and the scrambling code SC index (s) is output to the channel demapping unit 27. The OFDM symbol timing is output to the DFT converter 26 and the like. The channel demapping unit 27 generates a local scrambling code SC using the scrambling code SC index (s), and suffers from the OFDM symbol input to the channel demapping unit 27 by the descrambling process. The scrambling code SC is deleted, and the broadcast channel BCH is extracted. Note that the synchronization channel SCH signal is not scrambled on the transmission side, and therefore the synchronization channel SCH signal can be separated (extracted) directly from the received signal.

  When the 20 MHz band identifier (y) is detected by the detected synchronization sequence index (g), that is, the cell specific information index (w), the cell search unit 31 determines that the synchronized base station apparatus has the system frequency bandwidth Is determined to be 20 MHz. As shown in FIG. 16, the radio unit (RX) 22 of the mobile station apparatus tunes to the center frequency of the upper 10 MHz bandwidth or the center frequency of the lower 10 MHz bandwidth according to the instruction of the base station apparatus, and performs non-initial cell search. To do.

  When performing the non-initial cell search, the control signal extraction unit 29 extracts the synchronization channel SCH1 signal of the adjacent cell at the center frequency of the upper 10 MHz bandwidth, for example, from the channel demapping unit 27 as shown in FIG. Output to the search unit 31. The cell search unit 31 detects and corrects the carrier frequency offset of the received signal, the OFDM symbol timing, identifies the synchronization sequence index (g) of the adjacent cell, that is, detects the cell specific information index (w) of the adjacent cell. The detected reference sequence index (r) of the neighboring cell is output to the channel estimation / CQI measuring unit 30, and the scrambling code SC index (s) of the neighboring cell is output to the channel demapping unit 27. The OFDM symbol timing of the adjacent cell is output to the DFT converter 26 and the like. The channel demapping unit 27 generates a local scrambling code SC using the scrambling code SC index (s) of the adjacent cell, and the disk demapping unit 27 applies a disc to the OFDM symbol of the adjacent cell input to the channel demapping unit 27. By the rumble process, the received scrambling code SC is deleted, and the broadcast channel of the adjacent cell is extracted.

(2) Extraction of Reference Signal RS and Channel Estimation / CQI Measurement The channel demapping unit 27 uses the scrambling group SG index (s) from the cell search unit 31 to generate a local scrambling code SC, and descrambles Perform processing. The control signal extraction unit 29 extracts the reference symbol from the channel demapping unit 27 and outputs the reference symbol to the channel estimation / CQI measurement unit 30 and the cell search unit 31. The channel estimation / CQI measurement unit 30 performs radio channel state estimation (channel estimation) using the reference symbol, and outputs it to a user data demodulation unit (not shown).

  On the other hand, the power of the reference signal RS of each RB is measured using the local reference signal RS, converted into a signal format defined in advance by the system, and fed back to the base station apparatus through the uplink. When the GCL sequence is used as the reference symbol, for example, a local reference signal is generated by the reference sequence index (r), the extracted reference signal RS is correlated, and IDFT conversion (a frequency domain signal is converted into a time domain). Channel estimation can be performed by a series of filtering processing (removal of interference components and noise components) and DFT transform (time domain signal is converted to frequency domain).

(3) Extraction of Broadcast Channel BCH Signal and Shared / Dedicated Control Signal The control signal extraction unit 29 extracts the broadcast channel BCH signal shown in FIG. 13 and provides broadcast information such as system-specific parameters and cell / sector-specific parameters. Demodulate. The individual control information such as the shared control signal required by the mobile station apparatus, the layer 1 / layer 2 control signal, the position of the RB assigned to the packet data addressed to the own station, and the AMCS parameter is extracted from the first OFDM symbol of each RB. The individual control signal is demodulated and output to a user data demodulator (not shown).

(4) Cell search method (procedure)
The cell search unit 31 receives a plurality of reference signals RS and a multiplexed signal of the synchronization channel SCH transmitted from a plurality of sectors and a plurality of transmission antennas. In the cell search unit 31, carrier frequency offset synchronization, OFDM symbol timing synchronization, radio frame timing synchronization, sector specific information index (w), reference sequence index (r), scrambling code SC index (s) identification, and each reference signal RS received power is detected and output as a cell search result. The reference sequence index (r) is output to the channel estimation / CQI measurement unit 30, a local reference signal RS is generated, and channel estimation and CQI calculation are performed. The scrambling code SC index (s) is output to the channel demapping unit to perform descrambling processing of the scrambling code.

  FIG. 11 is a flowchart showing the operation of the cell search unit 31. Here, the operation will be described from the state of camping (waiting) when power is turned on or when returning from outside the coverage. In order to search for a cell, the mobile station apparatus starts an initial cell search (step S1). Band search is performed at an interval of channel number UARFCN (200 kHz), and a synchronization channel SCH (SCH2 in the case of a 20 MHz system frequency bandwidth) is detected at the RF center frequency of the base station apparatus. Synchronize carrier frequency offset and OFDM symbol timing corresponding to the maximum power synchronization channel SCH by time-domain auto-correlation or cross-correlation processing for the received signals of the plurality of synchronization channels SCH, and a synchronization sequence index ( g) is detected (step S1).

  Next, it is determined whether the detected synchronization sequence index (g), that is, the corresponding cell specific information index (w) is a 20 MHz band identifier (y) (step S2), and a 20 MHz band identifier (y). If the cell ID (c) is not, the process proceeds to step S5, where the reference sequence index (r) and the scrambling code index (s) are identified, and the broadcast channel BCH is demodulated (step S5). S5), transition to the standby state (idle mode). The non-initial cell search is performed at the RF center frequency of the base station apparatus.

  On the other hand, if it is a 20 MHz band identifier (y) in step S2, frequency shift is performed (step S3), cell ID (c) is detected by the synchronization channel SCH1 (step S4), and reference sequence index (r). And the scrambling code index (s) are identified, the broadcast channel BCH is demodulated (step S5), and a transition is made to the standby state (idle mode). Non-initial cell search is performed at the center frequency of upper / lower 10 MHz.

  The standby cell search is performed according to the flowchart shown in FIG. That is, the cell ID (c) is detected by the synchronization channel SCH1 (step S6), the reference sequence index (r) and the scrambling code index (s) are identified, and the broadcast channel BCH is demodulated (step S7). ).

  As described above, when the mobile station apparatus detects the 20 MHz band identifier (y), the mobile station apparatus performs frequency shift to the upper / lower 10 MHz. At this time, the upper / lower frequency positions may be selected at random by the mobile station apparatus, or may be selected using the hash value of the identification ID of the mobile station apparatus. Use of the hash value of the mobile station apparatus identification ID is effective because the network can manage the frequency position of the mobile station apparatus.

  As described above, when the synchronization channels SCH1 and SCH2 in the 20 MHz system frequency bandwidth are arranged, the non-initial cell search is performed in the same frequency band. Therefore, for example, when the mobile station apparatus stores the frequency position of the synchronization channel SCH in the memory in advance, that is, when it is not necessary to scan the frequency raster in the band search, the synchronization channel SCH2 having a center frequency of 20 MHz. Need not be used at all. Therefore, the synchronization channel SCH2 having a center frequency of 20 MHz has a minimum function, and the necessity of arranging a broadcast channel BCH having a center frequency of 20 MHz can be eliminated. In this respect, this embodiment is also effective in terms of effective use of resources.

  Here, the SCH1 is configured to be arranged at the center frequency of the upper 10 MHz bandwidth or the lower 10 MHz bandwidth, but the SCH1 can also be arranged at a position temporally divided from the SCH2. In particular, in order to correspond to a mobile station apparatus having 10 MHz and 20 MHz mobile station apparatus capability (UE Capability), 20 MHz SCH 1 is arranged in the upper 10 MHz bandwidth or the lower 10 MHz bandwidth, but the system only has the 20 MHz mobile station apparatus capability. In, it is effective to arrange SCH1 and SCH2 at positions separated in terms of time or frequency. It is possible to detect the system frequency bandwidth by separating SCH1 and SCH2 in terms of time or frequency and receiving SCH2, because the processing procedure in different system frequency bandwidths is different from the detection of SCH2, respectively. It is effective in the sense that the system frequency bandwidth can be configured differently.

  The characteristic operations of the present invention as described above are performed by causing a computer to execute a program. That is, the program of the present invention is a program for controlling a cell search operation of a mobile station apparatus applied to a radio communication system using a plurality of different system frequency bandwidths, and extracts a synchronization channel signal from a received signal. Processing, processing for identifying a synchronization sequence index based on the synchronization channel signal, and processing for detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index and performing an initial cell search When the identifier is detected, the identifier is mapped to the center frequency band of each bandwidth when the system frequency bandwidth corresponding to the identifier is divided for each maximum reception frequency bandwidth. Non-initial cell search based on unsynchronized synchronization channel signal It is characterized in that a series of processes including, configured as instructions a computer can execute.

  In this way, since the synchronization channel signal with an identifier having an identifier indicating the system frequency bandwidth is mapped to the center frequency band of the system frequency bandwidth, the mobile station apparatus having a different frequency bandwidth to be used is By receiving the synchronization channel (SCH2) in the center frequency band, it is possible to reliably grasp the system frequency bandwidth.

  The above program can be obtained in a state of being recorded on a recording medium such as a CD-ROM or a DVD. In addition, such a program is transmitted by a computer as a transmission device via a transmission medium such as a communication network including a public telephone line, a dedicated telephone line, a cable TV line, a wireless communication line, etc. constituting the network. It can also be obtained by receiving the received signal. This signal is a computer data signal embodied in a predetermined carrier wave including a program. At the time of this transmission, it is only necessary to transmit at least a part of the program in the transmission medium. That is, it is not necessary for all data constituting the program to exist on the transmission medium at a time. Further, the transmission method for transmitting a program from the computer includes a case where data constituting the program is transmitted continuously and a case where it is transmitted intermittently.

It is a figure which shows the example of the downlink radio frame structure and radio channel arrangement | positioning of EUTRA assumed based on the proposal of 3GPP. It is a figure which shows the example of arrangement | positioning of the downlink synchronization channel SCH of this embodiment whose system frequency bandwidth is 20 MHz. It is a figure which shows the system frequency bandwidth of 20 MHz, 10 MHz, 5 MHz, 2.5 MHz, and 1.25 MHz. It is a figure which shows a synchronous sequence index and a cell specific information index. It is a figure which shows a synchronous sequence index and a cell specific information index. It is a figure which shows a synchronous sequence index and a cell specific information index. It is a figure which shows a synchronous sequence index and a cell specific information index. It is a block diagram which shows the transmission part of a base station apparatus. It is a figure which shows the example of mapping of the scrambling code SC. It is a block diagram which shows the receiving part of a mobile station apparatus. It is a figure which shows the procedure of an initial cell search and a non-initial cell search. It is a flowchart which shows the procedure of a standby cell search. It is a figure which shows the example of the downlink radio frame structure and radio channel arrangement | positioning of EUTRA assumed based on the proposal of 3GPP. It is a flowchart which shows the example of the cell search procedure in an EUTRA system. It is a figure which shows the system frequency bandwidth of 20 MHz, 10 MHz, 5 MHz, 2.5 MHz, and 1.25 MHz. It is a figure which shows the method of the frequency band position designation (center frequency shift) which should be used of the mobile station apparatus which uses a 10-MHz bandwidth with respect to the base station apparatus which uses a 20-MHz system frequency bandwidth. It is a figure which shows arrangement | positioning of the synchronous channel SCH with respect to the base station apparatus which has a system frequency bandwidth of 20 MHz. It is a figure which shows the example of the center frequency of the frequency band which the mobile station apparatus which uses a 10-MHz bandwidth with respect to the base station apparatus which uses a 20-MHz system frequency bandwidth. It is a figure which shows the structure of the synchronous channel SCH. It is a figure which shows the structure of the synchronous channel SCH. It is a figure which shows the structure of the synchronous channel SCH. It is a figure which shows the structure of the synchronous channel SCH. It is a figure which shows the structure of the synchronous channel SCH.

Explanation of symbols

10 Transmitter (base station device)
11 S / P conversion unit 12 Control signal generation unit 13 Channel mapping unit 14 IDFT conversion unit 15 P / S conversion unit 16 CP insertion unit 17 DAC processing unit (digital / analog signal conversion)
18 Radio section (TX)
19 Transmitting antenna 20 Receiving unit (mobile station device)
21 receiving antenna 22 radio unit (RX)
23 ADC processing unit (analog / digital signal conversion)
24 CP deletion unit 25 S / P conversion unit 26 DFT conversion unit 27 Channel demapping unit 28 P / S conversion unit 29 Control signal extraction unit 30 Channel estimation / CQI measurement unit 31 Cell search unit

Claims (8)

A base station apparatus applied to a wireless communication system using a plurality of different system frequency bandwidths,
A control signal generator for generating a synchronization channel signal with an identifier having an identifier indicating a system frequency bandwidth;
A base station apparatus comprising: a channel mapping unit that maps the synchronization channel with an identifier to a center frequency band of the system frequency bandwidth. The control signal generator generates a synchronization channel signal without the identifier;
The channel mapping unit maps the synchronization channel signal not having the identifier to a center frequency band of each bandwidth when the system frequency bandwidth is divided for each maximum reception frequency bandwidth of a mobile station apparatus that is a communication partner. The base station apparatus according to claim 1, wherein:   The base station apparatus according to claim 1 or 2, wherein a part of a cell specific information index included in the synchronization channel signal is the identifier. A mobile station apparatus applied to a wireless communication system using a plurality of different system frequency bandwidths,
A control signal extractor for extracting a synchronization channel signal from the received signal;
A cell search unit for performing an initial cell search for identifying a synchronization sequence index based on the synchronization channel signal and detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index; A mobile station apparatus.   When the cell search unit detects the identifier, the system frequency bandwidth corresponding to the identifier is mapped to the center frequency band of each bandwidth when divided for each maximum reception frequency bandwidth of itself. 5. The mobile station apparatus according to claim 4, wherein non-initial cell search is performed based on a synchronization channel signal not having the identifier.   A wireless communication system comprising the base station apparatus according to any one of claims 1 to 3 and the mobile station apparatus according to claim 4 or 5. A cell search method for a mobile station apparatus applied to a wireless communication system using a plurality of different system frequency bandwidths,
Extracting a synchronization channel signal from the received signal;
Identifying a synchronization sequence index based on the synchronization channel signal;
Performing an initial cell search by detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index;
When the identifier is detected, the system frequency bandwidth corresponding to the identifier is not synchronized with the identifier mapped to the center frequency band of each bandwidth when divided for each maximum reception frequency bandwidth of itself. And a non-initial cell search based on the channel signal. A program for controlling a cell search operation of a mobile station apparatus applied to a wireless communication system using a plurality of different system frequency bandwidths,
A process of extracting a synchronization channel signal from the received signal;
A process of identifying a synchronization sequence index based on the synchronization channel signal;
A process of detecting an identifier indicating a system frequency bandwidth from a cell specific information index corresponding to the synchronization sequence index and performing an initial cell search;
When the identifier is detected, the system frequency bandwidth corresponding to the identifier is not synchronized with the identifier mapped to the center frequency band of each bandwidth when divided for each maximum reception frequency bandwidth of itself. A program comprising a series of processes including a process of performing a non-initial cell search based on a channel signal as an instruction group that can be executed by a computer.

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