JP5319303B2 - Base station apparatus, mobile station, synchronization signal transmission method, and synchronization signal reception method - Google Patents

Abstract

A radio communication system includes a plurality of mobile stations and a plurality of base station devices which perform communication with the mobile stations by using the OFDM method. The radio communication system includes sequence definition means which defines a sequence of first synchronization signals and a transmission patter of first synchronization signals and second synchronization signals. According to a cell ID or a cell ID group, the transmission timings of a P-SCH sequence and P-SCH and S-SCH are decided by a synchronization signal control unit 209<SUB>1</SUB>.

Description

  The present invention relates to a radio communication system to which orthogonal frequency division multiplexing OFDM (Orthogonal Frequency Division Multiplexing) is applied in the downlink, and more particularly to a base station apparatus, a mobile station, a synchronization signal transmission method, and a synchronization signal reception method communication control method.

  Long Term Evolution (LTE) has been studied by W-CDMA standardization organization 3GPP as a successor to W-CDMA and HSDPA, and as a radio access system, downlink is OFDM and uplink SC-FDMA (Single-Carrier Frequency Multiple Access) has been studied (see, for example, Non-Patent Document 1).

  OFDM is a method in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is transmitted on each frequency band, and the subcarriers interfere with each other even though they partially overlap on the frequency. By arranging them closely, it is possible to achieve high-speed transmission and increase frequency utilization efficiency.

  SC-FDMA is a transmission method that can reduce interference between terminals by dividing a frequency band and performing transmission using different frequency bands among a plurality of terminals. Since SC-FDMA has a feature that fluctuations in transmission power are reduced, it is possible to realize low power consumption and wide coverage of a terminal.

  In LTE, two types of CPs, Long CP and Short CP, having different lengths are prepared as cyclic prefix (CP) for reducing the influence of intersymbol interference caused by delay waves in OFDM. For example, the Long CP is applied to a cell having a large cell radius, and is applied when an MBMS (Multimedia Broadcast Multicast Service) signal is transmitted, and the Short CP is applied to a cell having a small cell radius. When the Long CP is applied, the number of OFDM symbols in 1 Transmission Time Interval (TTI) is 6, and when the Short CP is applied, the number of OFDM symbols in 1 TTI is 7. TTI is also called a sub-frame.

  By the way, in general, in a wireless communication system using W-CDMA, LTE, or the like, a mobile station is based on a synchronization signal or the like at power-on, standby, communication, or intermittent reception during communication. Therefore, it is necessary to detect a cell having good radio quality for the local station. This process is called cell search in the sense of searching for a cell to which a radio link is to be connected. The cell search method is generally determined based on the time required for the cell search and the processing load on the mobile station when performing the cell search. That is, the cell search method must be a method in which the time required for the cell search is short and the processing load on the mobile station when performing the cell search is small.

  In W-CDMA, cell search is performed using two types of synchronization signals, Primary SCH (P-SCH) and Secondary SCH (S-SCH). Similarly, in LTE, P- The use of two types of synchronization signals, SCH and S-SCH, has been studied.

For example, as a cell search method, a cell search method for transmitting a P-SCH having one sequence and an S-SCH having a plurality of sequences at a time interval of once every 5 ms has been studied (Non-Patent Document). 2). In the above method, the downlink reception timing from each cell is specified by the P-SCH, and the reception frame timing is detected and the cell ID or the group (Group ID) is detected by the S-SCH transmitted to the same TTI. The cell-specific information such as is specified. Here, for the demodulation and decoding of the S-SCH, it is generally possible to use a channel estimation value obtained from the P-SCH. When cell IDs are grouped, the cell IDs are detected from the cell IDs belonging to the group IDs of the detected cells. For example, the cell ID is calculated based on the signal pattern of the pilot signal. Alternatively, the cell ID may be included as an information element of the S-SCH without grouping the cell IDs. In this case, the mobile station can detect the cell ID when the S-SCH is demodulated and decoded.
However, when the cell search method is applied, in an inter-station synchronization system in which signals from each cell are synchronized, based on a channel estimation value obtained from P-SCHs transmitted in the same sequence from a plurality of cells. Since S-SCH transmitted in different sequences from a plurality of cells is demodulated and decoded, there is a problem that the transmission characteristics of S-SCH deteriorates. Here, the transmission characteristics include, for example, the time required for cell search. In the case of a non-stationary synchronization system in which signals from each cell are not synchronized, the reception timing of the P-SCH sequence transmitted from a plurality of cells differs among the plurality of cells. No problem arises.
In order to prevent the deterioration of S-SCH characteristics in the inter-station synchronization system as described above, a cell search method in which the number of P-SCH sequences is 1 to 2 or more, for example, 7 or 8, is being studied. (Non-Patent Document 3).
Alternatively, a method of transmitting P-SCH at different transmission intervals for each cell has been proposed in order to prevent S-SCH characteristic deterioration in the inter-station synchronization system as described above (Non-Patent Document 4). In the above-described method, P-SCH having different reception timings from a plurality of cells can be used in S-SCH demodulation / decoding, so that it is possible to prevent the above-described deterioration of S-SCH characteristics.
By the way, it is considered that the larger the number of P-SCH sequences in Non-Patent Document 3 and the type of P-SCH transmission interval in Non-Patent Document 4 described above, the better. This is because, when the number of P-SCH sequences and the types of P-SCH transmission intervals are small, the probability that the P-SCH sequences are the same in adjacent cells, or the P-SCH transmission intervals are the same. This is because the probability of S-SCH characteristic deterioration in the inter-station synchronization system increases.
In addition, the time required for the cell search, that is, the cell search transmission characteristics and the processing load of the mobile station when performing the cell search are in a trade-off relationship, and the cell setting depends on the parameter setting or operation method. It is desirable to be able to select whether the transmission characteristics of search are important or whether the processing load of the mobile station is important when performing cell search.
3GPP TR 25.814 (V7.0.0), "Physical Layer Aspects for Evolved UTRA," June 2006 R1-062990, Outcome of cell search drafting session R1-062636, Cell Search Performance in Tightly Synchronized Network for E-UTRA R1-070428, Further analysis of initial cell search for Approach 1 and 2-single cell scenario BMPopovic, "Generalized chirp-like polyphase sequence with optimum correlation properties," IEEE Trans. Inform. Theory, vol.38, pp. 1406-1409, July 1992. RLFrank and SAZadoff, "Phase shift pulse codes with good periodic correlation properties," IRE Trans. Inform. Theory, vol. IT-8, pp. 381-382, 1962. R1-062487 Hierarchical SCH signals suitable for both (FDD and TDD) modes of E-UTRA R1-070146, S-SCH Sequence Design

  However, the background art described above has the following problems.

  In the case of the cell search method in which the number of P-SCH sequences is 7 or 8 (Non-patent Document 3), the mobile station uses the P-SCH to downlink by increasing the number of P-SCH sequences. The processing load for specifying the timing of the signal increases.

  Alternatively, in the case of a method of transmitting P-SCH at different transmission intervals for each cell (Non-Patent Document 4), there is a limitation on the type of transmission interval of P-SCH, and due to the above limitation, the characteristics of S-SCH are There is a possibility of deterioration. That is, in the above method, there are only three types of P-SCH transmission intervals, and therefore there is a possibility that the characteristics of S-SCH may deteriorate in an area where four or more cells are congested. In the above method, since the transmission interval of the P-SCH differs between the Long CP and the Short CP, it is necessary to perform a cell search assuming the cases of the Long CP and the Short CP. In other words, the processing load is twice that of a method that does not consider whether Long CP or Short CP is used in the cell.

  Therefore, in view of the above-described problems, the present invention aims to prevent degradation of S-SCH characteristics in an inter-station synchronization system and reduce the processing load on a mobile station in cell search, A mobile station, a wireless communication system, a synchronization signal transmission method, and a synchronization signal reception method are provided.

  Another object of the present invention is to provide a base station apparatus and a mobile station that can flexibly adjust the trade-off relationship between the S-SCH characteristic degradation in the inter-station synchronization system and the processing load of the mobile station in the cell search. Another object of the present invention is to provide a radio communication system, a synchronization signal transmission method, and a synchronization signal reception method.

In order to solve the above problems, the wireless communication system of the present invention is:
A wireless communication system comprising a plurality of mobile stations and a plurality of base station apparatuses that communicate with the mobile stations using an OFDM scheme in the downlink:
Sequence defining means for defining a plurality of first synchronization signal sequences;
Transmission pattern defining means for defining transmission patterns of a plurality of first synchronization signals and second synchronization signals;
It is one of the features to provide.

In order to solve the above problems, the base station apparatus of the present invention
A base station apparatus in a wireless communication system comprising a plurality of mobile stations and a plurality of base station apparatuses that communicate with the mobile station using an OFDM scheme in the downlink:
Sequence selection means for selecting one first synchronization signal sequence from a plurality of first synchronization signal sequences;
A transmission pattern selection means for selecting a transmission pattern of one first synchronization signal and a second synchronization signal from a plurality of transmission patterns of the first synchronization signal and the second synchronization signal;
Transmitting means for transmitting the first synchronization signal and the second synchronization signal;
It is one of the features to provide.

In order to solve the above problems, the mobile station of the present invention
A mobile station used in a wireless communication system including a base station apparatus that performs communication using the OFDM scheme in the downlink:
First receiving means for receiving a first synchronization signal;
Sequence acquisition means for acquiring the type of sequence of the first synchronization signal;
Transmission pattern acquisition means for acquiring transmission patterns of the first synchronization signal and the second synchronization signal;
Detection means for detecting a cell ID or a set of cell IDs based on a type of the first synchronization signal sequence and a transmission pattern of the first synchronization signal and the second synchronization signal;
One of the features is to have

In order to solve the above-described problem, a synchronization signal transmission method of the present invention includes:
A synchronization signal transmission method in a wireless communication system comprising a mobile station and a base station apparatus that communicates with the mobile station using an OFDM scheme in the downlink:
A sequence selection step of selecting one first synchronization signal sequence from a plurality of first synchronization signal sequences;
A transmission pattern selection step of selecting a transmission pattern of one first synchronization signal and a second synchronization signal from a plurality of transmission patterns of the first synchronization signal and the second synchronization signal;
It is one of the features to provide.

In order to solve the above-described problem, a synchronization signal receiving method of the present invention includes:
A synchronization signal receiving method in a radio communication system comprising a mobile station and a base station apparatus that communicates with the mobile station using an OFDM scheme in the downlink:
A first receiving step for receiving the first synchronization signal;
A sequence acquisition step of acquiring a sequence type of the first synchronization signal;
A transmission pattern acquisition step of acquiring transmission patterns of the first synchronization signal and the second synchronization signal;
A detection step of detecting a cell ID or a set of cell IDs based on a type of the first synchronization signal sequence and a transmission pattern of the first synchronization signal and the second synchronization signal;
It is one of the features to provide.

  According to the embodiments of the present invention, a base station apparatus, a mobile station, a wireless communication system, which can prevent the deterioration of S-SCH characteristics in an inter-station synchronization system and reduce the processing load of a mobile station in a cell search, A synchronization signal transmission method and a synchronization signal reception method can be realized.

  In addition, a base station apparatus, mobile station, radio communication system, and synchronization signal transmission method capable of flexibly adjusting the trade-off relationship between S-SCH characteristic degradation in an inter-station synchronization system and processing load on a mobile station in cell search In addition, a synchronization signal receiving method can be realized.

It is a block diagram which shows the structure of the radio | wireless communications system concerning the Example of this invention. It is explanatory drawing which shows the structure of a wireless frame. It is explanatory drawing which shows the structure of TTI. It is a partial block diagram which shows the base station apparatus which concerns on one Example of this invention. It is a block diagram which shows the baseband signal processing part of the base station apparatus which concerns on one Example of this invention. It is a figure which shows an example of a synchronous signal transmission pattern. It is a figure which shows an example of the combination of a P-SCH sequence number and a synchronous signal transmission pattern. It is a figure which shows an example of a synchronous signal transmission pattern. It is a figure which shows an example of the combination of a P-SCH sequence number and a synchronous signal transmission pattern. It is a figure which shows an example of a synchronous signal transmission pattern. It is a figure which shows an example of the combination of a P-SCH sequence number and a synchronous signal transmission pattern. It is a figure which shows an example of a synchronous signal transmission pattern. It is a figure which shows an example of the combination of a P-SCH sequence number and a synchronous signal transmission pattern. It is a partial block diagram which shows the mobile station which concerns on one Example of this invention. 5 is a flowchart illustrating a synchronization signal transmission method according to an embodiment of the present invention. 5 is a flowchart illustrating a synchronization signal receiving method according to an embodiment of the present invention.

Explanation of symbols

50 ₁ , 50 ₂ , 50 ₃ , 50 _k cells 100 ₁ , 100 ₂ , 100 ₃ , 100 _n mobile station 102 transmitting / receiving antenna 104 amplifier unit 106 transmitting / receiving unit 108 baseband processing unit 109 cell search unit 110 call processing unit 112 application unit 200 base station apparatus 202 transmission / reception antenna 204 amplifier unit 206 transmission / reception unit 208 baseband processing unit 210 call processing unit 212 transmission path interface 208 ₁ RLC processing unit 208 ₂ MAC processing unit 208 ₃ encoding unit 208 ₄ data modulation unit 208 ₅ multiplexing unit 208 ₆ Series-parallel converter 208 ₇ Multiplier 208 ₈ Multiplier 208 ₉ Scramble code generator 208 ₁₀ Amplitude adjuster 208 ₁₁ Synthesizer 208 ₁₂ IFFT (IDFT)
208 ₁₃ CP adding section 208 ₁₃
209 Synchronization signal generator 209
209 ₁ synchronization signal control unit 209 ₂ synchronization signal generation unit 209 ₃ data modulation unit 209 ₄ serial / parallel conversion unit 209 ₅ multiplier 209 ₆ amplitude adjustment unit 300 access gateway device 400 core network

  Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  A radio communication system according to an embodiment of the present invention will be described with reference to FIG.

The wireless communication system 1000 is a system to which, for example, Evolved UTRA and UTRAN (also known as Long Term Evolution or Super 3G) is applied, and a plurality of base station apparatuses (eNBs: eNode B) 200 _m (200 ₁ , 200 _2). , 200 ₃ ,... 200 _m , m is an integer of m> 0) and a plurality of mobile stations (UE: User Equipment) 100 _n (100 ₁ , 100 ₂ , 100 ₃ ,... 100 _n , n is n > An integer of> 0). The base station device 200 _m is connected to an upper station, for example, the access gateway device 300, and the access gateway device 300 is connected to the core network 400. Here, the mobile station 100 _n is connected to one of the base station apparatuses 200 _m and Evolved UTRA and in any of the cells 50 _k (50 ₁ , 50 ₂ , 50 ₃ ,... 50 _k , k is an integer of k> 0). Communication is performed by UTRAN. Here, the mobile station 100 _n establishes a communication channel with any one of the base station devices 200 _m and establishes a communication channel with any one of the base stations 200 _m and the base station 200 _m , so that there is no communication. It is assumed that things in a state are mixed.
The base station device 200 _m transmits a synchronization signal. The mobile station 100 _n is located in one of the cells 50 _k (50 ₁ , 50 ₂ , 50 ₃ ,... 50 _k , k is an integer of k> 0), and is turned on or in communication At the time of intermittent reception or the like, a cell search for detecting a cell having good radio quality for the own station is performed based on the synchronization signal. In other words, the mobile station 100 _n detects the symbol timing and the frame timing using the synchronization signal, and uses a cell ID (cell-specific scramble code generated from the cell ID) or a set of cell IDs (hereinafter cell ID). Cell-specific control information such as a group) is detected.
Here, the cell search is performed both when the mobile station 100 _n is in a communication state and when it is in a no-communication state. For example, the cell search in the communication state includes a cell search for detecting a cell having the same frequency and a cell search for detecting a cell having a different frequency. The cell search in the no-communication state includes, for example, a cell search at power-on and a cell search at standby.
Hereinafter, since the base station apparatus 200 _m (200 ₁ , 200 ₂ , 200 ₃ ,... 200 _m ) has the same configuration, function, and state, the base station apparatus 200 _m is hereinafter referred to as the base station 200 _m unless otherwise specified. Proceed with the explanation.

Hereinafter, since the mobile station 100 _n (100 ₁ , 100 ₂ , 100 ₃ ,... 100 _n ) has the same configuration, function, and state, the following description will be given as the mobile station 100 _n unless otherwise specified. To proceed.
Hereinafter, since the cells 50 _k (50 ₁ , 50 ₂ , 50 ₃ ,... 50 _k ) have the same configuration, function, and state, the following description will be given as the cell 50 _k unless otherwise specified. .

  Radio communication system 1000 employs OFDM (Orthogonal Frequency Division Multiple Access) for the downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) for the uplink as the radio access scheme. As described above, OFDM is a scheme in which a frequency band is divided into a plurality of narrow frequency bands (subcarriers) and data is transmitted on each frequency band. SC-FDMA is a transmission method that can reduce interference between terminals by dividing a frequency band and performing transmission using different frequency bands among a plurality of terminals.

  Here, communication channels in Evolved UTRA and UTRAN will be described.

For the downlink, a downlink shared physical channel (PDSCH) shared by each mobile station 100 _n and a downlink control channel for LTE are used. In the downlink, the mobile station information and transport format information mapped to the downlink shared physical channel, the mobile station information and transport format information mapped to the uplink shared physical channel, by the downlink control channel for LTE, The acknowledgment information of the uplink shared physical channel is notified, and user data is transmitted through the downlink shared physical channel.

In the downlink, the base station apparatus 200 _m transmits a synchronization signal for the mobile station 100 _n to perform cell search.

For the uplink, an uplink shared physical channel (PUSCH) shared by each mobile station 100 _n and an uplink control channel for LTE are used. There are two types of uplink control channels: channels that are time-multiplexed with uplink shared physical channels and channels that are frequency-multiplexed.

  In the uplink, downlink quality information (CQI: Channel Quality Indicator) to be used for scheduling of the shared physical channel in the downlink, adaptive modulation and coding (AMC: Adaptive Modulation and Coding) by the uplink control channel for LTE. And acknowledgment information (HARQ ACK information) of the downlink shared physical channel is transmitted. Also, user data is transmitted through the uplink shared physical channel.

  In downlink transmission, as shown in FIG. 2, one radio frame (Radio Frame) is 10 ms, and there are 10 TTIs in one Radio Frame. Also, as shown in FIG. 3, 1 TTI is composed of 2 subframes (Sub-frames), and 1 Sub-frame includes 6 OFDM symbols when a short CP (Short CP) is used, When long CP is used, it is composed of 7 OFDM symbols. The TTI described above may be referred to as a Sub-frame, and the Sub-frame described above may be referred to as a slot. In this case, ten sub-frames exist in one radio frame, and one sub-frame is composed of two slots (one slot), and one slot is 6 when a short CP (short CP) is used. When OFDM symbols and long CP are used, it is composed of 7 OFDM symbols.

Next, base station apparatus 200 _{m according} to an embodiment of the present invention will be described with reference to FIG.

  The base station apparatus 200 according to the present embodiment includes a transmission / reception antenna 202, an amplifier unit 204, a transmission / reception unit 206, a baseband signal processing unit 208, a call processing unit 210, and a transmission path interface 212.

Packet data transmitted from the base station apparatus 200 _m to the mobile station 100 _n via the downlink is subjected to baseband signal processing from the upper station located above the base station apparatus 200, for example, the access gateway apparatus 300 via the transmission path interface 212. Input to the unit 208.

  The baseband signal processing unit 208 divides and combines packet data, RLC layer transmission processing such as RLC (radio link control) retransmission control transmission processing, MAC retransmission control, for example, HARQ (Hybrid Automatic Repeat Request) transmission processing, Scheduling, transmission format selection, channel coding, inverse fast Fourier transform (IFFT) processing is performed, and the data is transferred to the transmission / reception unit 206. The baseband signal processing unit 208 performs a synchronization signal generation process as will be described later. The synchronization signal is multiplexed with the packet data and transferred to the transmission / reception unit 206.

  The transmission / reception unit 206 performs frequency conversion processing for converting the baseband signal output from the baseband signal processing unit 208 into a radio frequency band, and then is amplified by the amplifier unit 204 and transmitted from the transmission / reception antenna 202. Here, the baseband signal is the above-described packet data, synchronization signal, or the like.

On the other hand, for data transmitted from the mobile station 100 _n to the base station apparatus 200 _m via the uplink, a radio frequency signal received by the transmission / reception antenna 202 is amplified by the amplifier unit 204, and frequency-converted by the transmission / reception unit 206. It is converted into a band signal and input to the baseband signal processing unit 208.

  The baseband signal processing unit 208 performs FFT processing, IDFT processing, error correction decoding, MAC retransmission control reception processing, and RLC layer reception processing on the input baseband signal, via the transmission path interface 212. It is transferred to the access gateway device 300.

  The call processing unit 210 performs state management of the radio base station 200 and resource allocation.

  Next, the configuration of the baseband signal processing unit 208 will be described with reference to FIG. In addition, since the embodiment according to the present invention mainly relates to the downlink, in the same figure, the portion related to the downlink processing is shown, and the portion related to the uplink processing is omitted.

The baseband signal processing unit 208 includes a RLC processing unit _{208 1, MAC (Medium Access Control} ) processing unit 208 _2, an encoding unit 208 _3, a data modulation unit 208 _4, a multiplexing unit 208 _5, deserializer and parts 208 _6, a multiplier 208 _7, a multiplier 208 _8, a scramble code generator 208 _9, an amplitude adjusting unit _{208 10,} a combining unit _{208 11,} and IFFT (IDFT) _{208 12,} CP adding section 208 ₁₃ and a synchronization signal generation unit 209.

Transmission data sequence of downlink packet data received from the transmission path interface unit, in the RLC processing unit 208 _1, segmentation and concatenation, transmission processing of RLC layer transmission processing such as the RLC retransmission control is performed, MAC processor 208 in _2, the transmission processing of HARQ (Hybrid Automatic Repeat reQuest), scheduling, selection of transmission format, after the transmission processing of the MAC layer assignment such frequency resources is performed, encoded in the encoding unit 208 _3, a data is data modulated in modulation section 208 _4. Then, the transmission data sequence which is data-modulated, pilot symbol in multiplexing section 208 ₅ are multiplexed, the transmission data sequence in which the pilot symbols are multiplexed, on the frequency axis is parallel conversion in the serial-parallel conversion unit 208 ₆ It is converted into N information symbol sequences and arranged on the frequency axis. Here, the pilot symbol is, for example, a Donlink reference signal. For N information symbol sequences aligned on the frequency axis, in each of N multipliers 208 _7, the scrambling code scrambling code generating unit 208 ₉ outputs is multiplied in the frequency direction, further, the scrambling code Is multiplied by the amplitude adjustment sequence value output from the amplitude adjustment unit 208 _{10 in} each of the N multiplication units 208 ₈ , and is output to the synthesis unit 208 ₁₁ . Combining unit 208 _11, the symbol sequence of the scrambling code and amplitude adjusting sequence value-multiplied sequence length N, the sync signal generated in the synchronization signal generating unit 209, specific to corresponding one of the N subcarriers Multiplex on subcarriers.
As described below, TTI number and Sub-frame number synchronization signal is transmitted is determined by the synchronization signal control unit 209 _1. In the TTI number and the sub-frame number to which the synchronization signal is transmitted, downlink packet data having a sequence length N obtained by multiplying the synchronization signal generated in the synchronization signal generation unit 209 by the scramble code and the amplitude adjustment sequence value. In the TTI number and the sub-frame number that are multiplexed with respect to the symbol sequence of, and the synchronization signal is not synchronized, the synchronization signal generated in the synchronization signal generation unit 209 is not multiplexed, and is multiplied by the scramble code and the amplitude adjustment sequence value. only the symbol sequence of downlink packet data of the sequence length N is transmitted to the inverse Fourier transform unit 208 _12. The subcarrier on which the synchronization signal is multiplexed is located at the center of the entire bandwidth, for example. The bandwidth of the subcarrier on which the synchronization signal is multiplexed is 1.25 MHz.
The inverse Fourier transform unit (IFFT unit) 208 ₁₂ converts the N symbols into orthogonal multicarrier signals. CP adding section _{208 13,} to the multi-carrier signal for each Fourier target time, it inserts a CP. There are two types of CP length (CP length), Long CP and Short CP, and which CP length is used for each cell is selected.

A synchronization signal generation process in the synchronization signal generation unit 209 will be described. The synchronization signal is composed of a first synchronization signal (hereinafter referred to as P-SCH) and a second synchronization signal (hereinafter referred to as S-SCH). The synchronization signal generation unit 209 includes a synchronization signal control unit 209 ₁ , a synchronization signal generation unit 209 ₂ , a data modulation unit 209 ₃ , a serial / parallel conversion unit 209 ₄ , a multiplier 209 _5, and an amplitude adjustment unit 209 ₆ It comprises. The synchronization signal control unit 209 ₁ is connected to the synchronization signal generation unit 209 ₂ .

The synchronization signal control unit 209 ₁ determines the P-SCH sequence number, the P-SCH, and the S based on the cell ID or cell ID group of the cell for which the base station apparatus 200 _m provides communication using Evolved UTRA and UTRAN. -Determine the TTI number and Sub-frame number at which the SCH is transmitted. Here, the cell ID group is a set of cell IDs that can be specified when the mobile station demodulates and decodes the P-SCH and S-SCH. For example, after specifying the cell ID group, the mobile station may specify the cell based on the pilot signal, that is, the signal pattern of the Reference Signal. In this case, for example, the reference signal signal pattern and the cell ID are defined in advance.
The synchronization signal control unit 209 _1, the sequence number of the P-SCH, and notifies the sync signal generator 209 ₂ as the synchronization signal sequence information. Also, the TTI number and Sub-frame number the P-SCH and S-SCH are transmitted, and notifies the sync signal generator 209 ₂ as synchronization signal transmission timing information.

For example, as shown in FIG. 6, the wireless communication system 1000 defines four TTI numbers and Sub-frame numbers at which P-SCH and S-SCH are transmitted, and synchronization signal transmission pattern # 1, It is defined as # 2, # 3, # 4. In this example, since the synchronization signal is transmitted at TTI number # 1 and TTI number # 6, the synchronization signal is transmitted at equal intervals, and the averaging process of a plurality of frames is facilitated in the mobile station. Further, in this example, P-SCH is mapped to the last OFDM symbol of Sub-frame, so that P-SCH is used regardless of whether Long CP or Short CP is used in the mobile station. -SCH demodulation can be performed. This is because, in the last OFDM symbol of the sub-frame, the sixth OFDM symbol when the Long CP is applied and the seventh OFDM symbol when the Short CP are applied are temporally coincident. In other words, the timing at the beginning and end of the subframe is the same for both the short CP and the long CP.
Then, as shown in FIG. 7A, the wireless communication system 1000 uses the four P-SCH sequences and the two synchronization signal transmission patterns to form the eight P-SCH sequences and the synchronization signal transmission patterns. You may define the combination of. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number and the TTI number and Sub-frame number at which the P-SCH and S-SCH are transmitted can be determined. At this time, as one of information elements mapped to S-SCH, whether the synchronization signal, that is, P-SCH and S-SCH is transmitted in synchronization signal transmission patterns # 1 and # 4. May be included. At this time, the mobile station can determine, for example, whether the transmission is performed in the synchronization signal transmission pattern # 1 or # 4 based on the information element included in the S-SCH.
When the combinations shown in FIG. 7A are defined, if the combination numbers are different, the P-SCH does not collide in time or the sequence is different, so that the characteristics of the S-SCH deteriorate. It becomes possible to prevent.
Alternatively, as illustrated in FIG. 7B, the wireless communication system 1000 uses eight P-SCH sequences and two synchronization signal transmission patterns, and uses eight P-SCH sequences and synchronization signal transmission patterns. You may define the combination of. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated.
By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number, and the TTI number and Sub-frame number at which P-SCH and S-SCH are transmitted can be determined. At this time, as one of the information elements mapped to S-SCH, whether the synchronization signal, that is, P-SCH and S-SCH is transmitted in synchronization signal transmission pattern # 2 or # 3. The information may not be included. For example, the mobile station can determine whether the transmission is performed using the synchronization signal transmission pattern # 2 or # 3 based on the time interval of the received P-SCH.
When the combinations shown in FIG. 7B are defined, if the combination numbers are different, the P-SCH does not collide in time or the sequence is different, so that the characteristics of the S-SCH deteriorate. It becomes possible to prevent.
Alternatively, as illustrated in FIG. 7C, the wireless communication system 1000 uses nine P-SCH sequences and three synchronization signal transmission patterns to form nine P-SCH sequences and synchronization signal transmission patterns. You may define the combination of. At this time, in the wireless communication system, the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. You may associate with the combination of. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number, and the TTI number and Sub-frame number at which P-SCH and S-SCH are transmitted can be determined. At this time, as one of the information elements mapped to the S-SCH, the synchronization signal, that is, the P-SCH and the S-SCH are transmitted in any of the synchronization signal transmission patterns # 1, # 2, and # 3. It does not have to include information on whether or not For example, the mobile station can determine which of the synchronization signal transmission patterns # 1, # 2, and # 3 is transmitted based on the received P-SCH time interval.
When the combinations shown in FIG. 7C are defined, even when the combination numbers are different, there is a case where the P-SCH collides in time, but there is a case where the P-SCH does not collide in time. , It is possible to prevent a little deterioration of the characteristics of S-SCH. On the other hand, since only three P-SCH sequences are used to define a combination of nine P-SCH sequences and synchronization signal transmission patterns, the processing load on the mobile station can be reduced.
Furthermore, by defining the combination shown in FIG. 7C, it is possible to select the combination more flexibly when associating the cell ID or the cell ID group with the combination shown in FIG. 7C. Become. For example, only the combinations # 2, # 3, # 5, # 6, # 8, and # 9 can be used in a cell in an area where it is desired to prevent the degradation of S-SCH characteristics as much as possible. In this case, the P-SCH sequence and the synchronization signal transmission pattern used are equivalent to those in FIG. 7B, and the P-SCH does not collide with time, so that the degradation of the S-SCH characteristics is prevented as much as possible. Is possible. On the other hand, all of the combinations # 1 to # 9 can be used in a cell in an area where the S-SCH characteristics may be somewhat degraded. In this case, it becomes easy to associate the cell ID or the cell ID group with the combination.
In FIG. 7C, the synchronization signal patterns are # 1, # 2, and # 3, but may be # 2, # 3, and # 4 instead.
Alternatively, as shown in FIG. 7D, the wireless communication system 1000 uses two P-SCH sequences and four synchronization signal transmission patterns, and uses eight P-SCH sequences and synchronization signal transmission patterns. You may define the combination of. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number, and the TTI number and Sub-frame number at which P-SCH and S-SCH are transmitted can be determined. At this time, as one of information elements mapped to the S-SCH, the synchronization signal, that is, the P-SCH and the S-SCH are the synchronization signal transmission patterns # 1, # 2, # 3, and # 4. Information on which is being transmitted may be included. At this time, for example, the mobile station can determine which of the synchronization signal transmission patterns # 1, # 2, # 3, and # 4 is being transmitted based on the information element included in the S-SCH.
When the combinations shown in FIG. 7D are defined, there are cases where the P-SCHs collide in time even when the combination numbers are different, but there are cases where the P-SCHs do not collide in time. , It is possible to prevent a little deterioration of the characteristics of S-SCH. On the other hand, since only two P-SCH sequences are used to define a combination of eight P-SCH sequences and synchronization signal transmission patterns, the processing load on the mobile station can be reduced.
Furthermore, by defining the combinations shown in FIG. 7D, it is possible to select the combination more flexibly when associating the cell ID or cell ID group with the combination shown in FIG. 7D. . For example, only the combinations # 1, # 4, # 5, and # 8 can be used in a cell in an area where it is desired to prevent the degradation of S-SCH characteristics as much as possible. In this case, the P-SCH sequence and the synchronization signal transmission pattern to be used are equivalent to those in FIG. 7A, and the P-SCH does not collide with time, so that the degradation of the S-SCH characteristics is prevented as much as possible. Is possible. On the other hand, all the combinations # 1 to # 8 can be used in a cell in an area where the S-SCH characteristics may be somewhat degraded. In this case, the cell ID or the cell ID group can be easily associated with the above combination.
In FIG. 6 described above, P-SCH and S-SCH are transmitted using TTI number # 1 and TTI number # 6. Instead, they are transmitted using TTI number # 1 and TTI number # 5. Also good. That is, by transmitting the synchronization signal at different intervals, it becomes possible for the mobile station to easily detect the boundary of the radio frame from the P-SCH transmission interval. In this case, P-SCH and S-SCH transmitted at TTI number # 1 and TTI number # 5 are transmitted in the same manner as when P-SCH and S-SCH are transmitted at TTI number # 1 and TTI number # 6. The synchronization signal transmission patterns # 1, # 2, # 3, and # 4 shown in FIG. 6 are defined for the SCH, and the P-SCH shown in FIGS. 7 (a), (b), (c), and (d) are defined. Combinations of sequence numbers and synchronization signal transmission patterns are defined, and cell IDs or cell ID groups are associated with combinations of P-SCH sequence numbers and synchronization signal transmission patterns.

  Further, for example, as shown in FIG. 8, the wireless communication system 1000 defines two TTI numbers and Sub-frame numbers for transmitting P-SCH and S-SCH, and each includes synchronization signal transmission pattern # 1. , # 2 is defined. In this example, since the synchronization signal is transmitted at TTI number # 1 and TTI number # 5, the synchronization signal is transmitted at different intervals, and the boundary of the radio frame can be easily detected at the mobile station. It becomes possible. Further, in this example, P-SCH is mapped to the last OFDM symbol of Sub-frame, so that P-SCH is used regardless of whether Long CP or Short CP is used in the mobile station. -SCH demodulation can be performed. This is because, in the last OFDM symbol of the sub-frame, the sixth OFDM symbol when the Long CP is applied and the seventh OFDM symbol when the Short CP are applied are temporally coincident. A characteristic of this synchronization signal transmission pattern is that S-SCH is transmitted only to TTI number # 1 in one Radio Frame, and S-SCH is not transmitted in the case of TTI number # 5. Since the P-SCH transmission intervals are not uniform, the mobile station can easily detect the boundary of the radio frame, and the mobile station demodulates the S-SCH only at the TTI number # 1. In TTI number # 1, since the OFDM symbols for transmitting P-SCH and S-SCH are different between synchronization signal transmission patterns # 1 and # 2, P-SCH does not collide in time. It is possible to prevent the characteristics of S-SCH from deteriorating.

Then, as shown in FIG. 9, the wireless communication system 1000 uses the four P-SCH sequences and the two synchronization signal transmission patterns to combine the eight P-SCH sequences and the synchronization signal transmission patterns. It may be defined. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number, and the TTI number and Sub-frame number at which P-SCH and S-SCH are transmitted can be determined. At this time, as one of information elements mapped to S-SCH, whether the synchronization signal, that is, P-SCH and S-SCH is transmitted in synchronization signal transmission pattern # 1 or # 2 The information may not be included. At this time, for example, the mobile station can determine whether the transmission is performed in synchronization signal transmission pattern # 1 or # 2 based on the received P-SCH time interval.

Further, for example, as shown in FIG. 10, the wireless communication system 1000 defines three TTI numbers and Sub-frame numbers for transmitting P-SCH and S-SCH, respectively, and each includes synchronization signal transmission pattern # 1. , # 2, and # 3. In this example, since the synchronization signal is transmitted at TTI number # 1 and TTI number # 6, the synchronization signal is transmitted at equal intervals, and the averaging process of a plurality of frames is facilitated in the mobile station. This synchronization signal pattern has a feature that the transmission timing of the P-SCH does not match when the synchronization signal transmission patterns are different.
Then, as illustrated in FIG. 11, the wireless communication system 1000 uses the three P-SCH sequences and the three synchronization signal transmission patterns to combine nine P-SCH sequences and the synchronization signal transmission patterns. It may be defined. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m cell ID to which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Or based on a cell ID group, the sequence number of P-SCH and the TTI number and Sub-frame number by which P-SCH and S-SCH are transmitted can be determined. At this time, as one of information elements mapped to the S-SCH, the synchronization signal, that is, the P-SCH and the S-SCH are transmitted in any of the synchronization signal transmission patterns # 1, # 2, and # 3. May be included. At this time, for example, the mobile station can determine which of the synchronization signal transmission patterns # 1, # 2, and # 3 is transmitted based on the information element included in the S-SCH.
When the combinations shown in FIG. 11 are defined, when the combination numbers are different, it is possible to prevent the P-SCH from colliding in time or the characteristics of the S-SCH from being deteriorated due to different sequences. It becomes possible.

Further, for example, as shown in FIG. 12, the radio communication system 1000 defines four TTI numbers and Sub-frame numbers at which P-SCH and S-SCH are transmitted, and each includes a synchronization signal transmission pattern # 1. , # 2, # 3, and # 4. In this example, since the synchronization signal is transmitted at TTI number # 1 and TTI number # 6, the synchronization signal is transmitted at equal intervals, and the averaging process of a plurality of frames is facilitated in the mobile station. This synchronization signal pattern has a feature that the transmission timing of the P-SCH does not match when the synchronization signal transmission patterns are different. Also, the difference from the synchronization signal transmission pattern shown in FIG. 10 is that, in the synchronization signal transmission pattern shown in FIG. 10, the OFDM symbols to which P-SCH and S-SCH are mapped are within 1 Sub-frame. In the synchronization signal transmission pattern shown in FIG. 12, the OFDM symbols to which P-SCH and S-SCH are mapped are contained within 2 Sub-frames, that is, within 1 TTI, instead of within 1 Sub-frame.
Then, as illustrated in FIG. 13, the wireless communication system 1000 uses two P-SCH sequences and four synchronization signal transmission patterns to combine eight P-SCH sequences and synchronization signal transmission patterns. It may be defined. At this time, the wireless communication system is configured such that the cell ID or the cell ID group, the P-SCH sequence, and the synchronization signal transmission pattern are set so that the combination of the adjacent cell, the P-SCH sequence, and the synchronization signal transmission pattern is not the same. A combination may be associated. By such an association is performed by the wireless communication system 1000, the synchronization signal control unit 209 ₁ of the base stations 200 _m of the cell in which the base stations 200 _m provides communications using the Evolved UTRA and UTRAN Based on the cell ID or the cell ID group, the P-SCH sequence number, and the TTI number and Sub-frame number at which P-SCH and S-SCH are transmitted can be determined. At this time, as one of information elements mapped to the S-SCH, the synchronization signal, that is, the P-SCH and the S-SCH are the synchronization signal transmission patterns # 1, # 2, # 3, and # 4. It does not have to include information on which is being transmitted. At this time, for example, the mobile station can determine which of the synchronization signal transmission patterns # 1, # 2, # 3, and # 4 is transmitted based on the received P-SCH time interval.
When the combinations shown in FIG. 13 are defined, when the combination numbers are different, it is possible to prevent the P-SCH from colliding in time or the characteristics of the S-SCH from being deteriorated due to different sequences. It becomes possible.
In general, the communication area provided by the base station apparatus 200 _m is divided into two or more areas. This is called sectorization. When the base station apparatus 200 _m has a plurality of sectors, the cell ID or the cell ID group may be used as an ID of an area combining all the sectors of the base station apparatus 200 _{m. It} may be used as the ID of each sector of _m . When the cell ID or the cell ID group is used as an ID of an area including all the sectors of the base station apparatus 200 _m , the synchronization signal sequence, the TTI number and the sub-frame number at which the synchronization signal is transmitted. Is set for each base station apparatus 200 _m . When the cell ID or the cell ID group is used as the ID of each sector of the base station apparatus 200 _m , the combination of the synchronization signal sequence and the TTI number and the sub-frame number to which the synchronization signal is transmitted is It is set for each sector of the base station apparatus 200 _m .
Examples of P-SCH sequences include CAZAC (Constant Amplitude Zero Auto Correlation Sequence) sequences (Non-patent Literature 5), Frank Series (Non-patent Literature 6), and Modulated Franck Literature (Non-Patent Literature 6) ), Golay series (Non-Patent Document 7), Double Repeatable Golay Complementary sequence (Non-Patent Document 7), PN (Pseudo Random) series, and the like may be used.
In addition, as the S-SCH sequence, a two-layer S-SCH sequence (Non-Patent Document 8) obtained by multiplying an orthogonal sequence by a scramble sequence that is a non-orthogonal sequence may be used, or a plurality of different S-SCH sequences. S-SCH sequences (for example, Japanese Patent Application No. 2006-077821) may be used. As the orthogonal sequence, a Walsh-Hadamard sequence, a phase rotation orthogonal sequence, and a PN sequence may be used, and as the non-orthogonal sequence, a CAZAC sequence such as a GCL sequence, a Golay sequence, a Double Repeatable Complementary sequence, and the like are used. It may be.

Synchronization signal generator 209 _2, based on the synchronization signal sequence information and synchronization signal transmission timing information reported from the synchronization signal control unit 209 _1, generates a synchronization signal sequence. Here, the synchronization signal sequence is either P-SCH or S-SCH.

The synchronization signal sequence generated by the synchronization signal generation unit 209 ₂ is data-modulated by the data modulation unit 209 ₃ , and is further subjected to serial / parallel conversion by the serial / parallel conversion unit 209 ₄ to be converted into N _SCH symbol sequences on the frequency axis. Converted. The multiplier 209 ₅ multiplies the N _SCH symbol signals by the amplitude adjustment sequence value input by the amplitude adjustment unit 209 ₆ and outputs the result to the synthesis unit 208 ₁₁ .

  Next, the mobile station 100n according to the embodiment of the present invention will be described with reference to FIG.

In the figure, a mobile station 100 _n includes a transmission / reception antenna 102, an amplifier unit 104, a transmission / reception unit 106, a baseband signal processing unit 108, a cell search unit 109, a call processing unit 110, and an application unit 112. It has.

  As for downlink data, a radio frequency signal received by the transmission / reception antenna 102 is amplified by the amplifier unit 104, frequency-converted by the transmission / reception unit 106, and converted into a baseband signal. This baseband signal is subjected to FFT processing, error correction decoding, retransmission control reception processing, and the like in the baseband signal processing unit 108 and then transferred to the application unit 112. The baseband signal is also transmitted to the cell search unit 109.

  On the other hand, uplink packet data is input from the application unit 112 to the baseband signal processing unit 108. In the baseband signal processing unit 108, transmission processing for retransmission control (H-ARQ (Hybrid ARQ)), transmission format selection, channel coding, DFT processing, IFFT processing, and the like are performed and transferred to the transmission / reception unit 106.

  The transmission / reception unit 106 performs frequency conversion processing for converting the baseband signal output from the baseband signal processing unit 108 into a radio frequency band, and then is amplified by the amplifier unit 104 and transmitted from the transmission / reception antenna 102.

Further, cell search section 109 performs cell search using P-SCH and S-SCH included in the downlink signal. A cell search is performed based on the P-SCH sequence and the synchronization signal transmission pattern defined by the wireless communication system 1000 described above. That is, the cell ID or the cell ID group is detected by detecting the P-SCH sequence and the synchronization signal transmission pattern. When the cell ID group is detected, in order to specify the cells in the detected cell group, for example, the cells are specified based on the pilot signal and the signal pattern of the Dowlink Reference Signal. Then, after detecting the cell ID, broadcast information is received using a scrambling code associated with the cell ID, and the cell search process is terminated. The details of the P-SCH sequence and the synchronization signal transmission pattern defined by the wireless communication system 1000 are the same as those described in the base station apparatus 200 _m , and will not be repeated.
For example, the wireless communication system 1000 defines the synchronization signal transmission pattern in FIG. 6 and eight combinations of P-SCH sequences and synchronization signal transmission patterns in FIG. 7A and is mapped to the S-SCH. As one of the information elements, when the information on whether the synchronization signal, that is, P-SCH and S-SCH is transmitted in synchronization signal transmission pattern # 1 or # 4 is included, For example, the cell search unit 109 can determine which of the synchronization signal transmission patterns # 1 and # 4 is used for transmission based on an information element included in the S-SCH. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.
Alternatively, the wireless communication system 1000 defines the synchronization signal transmission pattern in FIG. 6 and the combinations of the eight P-SCH sequences and the synchronization signal transmission pattern in FIG. 7B and is mapped to the S-SCH. As one of the information elements, even if the synchronization signal, that is, the information indicating whether the P-SCH and S-SCH are transmitted in the synchronization signal transmission pattern # 2 or # 3 is not included, the cell The search unit 109 can determine, for example, whether the transmission is performed in the synchronization signal transmission pattern # 2 or # 3 based on the received P-SCH time interval. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.
Alternatively, the wireless communication system 1000 defines the synchronization signal transmission pattern in FIG. 6 and nine combinations of the P-SCH sequence and the synchronization signal transmission pattern in FIG. 7C and is mapped to the S-SCH. As one of the information elements, when the synchronization signal, that is, information indicating whether the P-SCH and S-SCH are transmitted in the synchronization signal transmission patterns # 1, # 2, and # 3 is not included In addition, the cell search unit 109 can determine which of the synchronization signal transmission patterns # 1, # 2, and # 3 is transmitted based on the received P-SCH time interval, for example. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.
Alternatively, the wireless communication system 1000 defines the synchronization signal transmission pattern in FIG. 6 and the combinations of the eight P-SCH sequences and the synchronization signal transmission pattern in FIG. 7D and is mapped to the S-SCH. As one of the information elements, information indicating whether the synchronization signal, that is, P-SCH and S-SCH is transmitted in synchronization signal transmission patterns # 1, # 2, # 3, and # 4 is included. The cell search unit 109 also determines whether the transmission is performed in the synchronization signal transmission patterns # 1, # 2, # 3, and # 4 based on the information element included in the S-SCH, for example. can do. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.

  Further, for example, information in which the wireless communication system 1000 defines the synchronization signal transmission pattern in FIG. 8 and the combinations of the eight P-SCH sequences and the synchronization signal transmission pattern in FIG. 9 and is mapped to the S-SCH. As one of the elements, even when the synchronization signal, that is, the information indicating whether the P-SCH and S-SCH are transmitted in the synchronization signal transmission patterns # 1 and # 2 is not included, the cell search is performed. For example, the unit 109 can determine whether the transmission is performed using the synchronization signal transmission pattern # 1 or # 2 based on the time interval of the received P-SCH. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.

Alternatively, the wireless communication system 1000 defines a combination of the synchronization signal transmission pattern in FIG. 10 and nine combinations of P-SCH sequences and synchronization signal transmission patterns in FIG. For example, if the synchronization signal, that is, information indicating whether the P-SCH and S-SCH are transmitted in the synchronization signal transmission pattern # 1, # 2, or # 3 is included, the cell For example, the search unit 109 can determine which of the synchronization signal transmission patterns # 1, # 2, and # 3 is transmitted based on the information element included in the S-SCH. Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.
Alternatively, the radio communication system 1000 defines the synchronization signal transmission pattern in FIG. 12 and the combinations of the eight P-SCH sequences and the synchronization signal transmission pattern in FIG. 13 and is mapped to the S-SCH As one of the cases, the synchronization signal, that is, the information indicating whether the P-SCH and the S-SCH are transmitted in the synchronization signal transmission patterns # 1, # 2, # 3, and # 4 is not included. However, the cell search unit 109 can determine, for example, which of the synchronization signal transmission patterns # 1, # 2, # 3, and # 4 is transmitted based on the received P-SCH time interval. . Then, cell search section 109 can detect a cell ID or a cell ID group by detecting a P-SCH sequence and a synchronization signal transmission pattern.

  The call processing unit 110 manages communication with the base station 200, and the application unit 112 performs processing related to a layer higher than the physical layer and the MAC layer.

  Next, a synchronization signal transmission method in the wireless communication system 1000 according to the present embodiment will be described with reference to FIG.

In step S1502, the synchronization signal generation unit 209 of the base stations 200 _m acquires the cell ID or cell ID group.

In step S1504, the synchronization signal generation unit 209 of the base stations 200 _m based on the cell ID or cell ID group, to determine the sequence of P-SCH. Here, the P-SCH sequence may be selected from a plurality of P-SCH sequences.

In step S1506, the synchronization signal generation unit 209 of the base stations 200 _m based on the cell ID or cell ID group, determines the synchronization signal transmission pattern. Here, the synchronization signal transmission pattern may be selected from a plurality of synchronization signal transmission patterns.

  Also, a synchronization signal receiving method in the radio communication system 1000 according to the present embodiment will be described with reference to FIG.

  In step S1602, the P-SCH is received, and the P-SCH sequence number is acquired.

  In step S1604, a synchronization signal transmission pattern is acquired from the P-SCH transmission interval or information mapped to the S-SCH.

  In step S1606, a cell ID or a cell ID group is specified by the P-SCH sequence number and the synchronization signal transmission pattern.

Note that the definition of the P-SCH sequence and the synchronization signal transmission pattern defined by the above-described wireless communication system 1000 must match between the base station apparatus 200 _m and the mobile station 100 _n, and parameters common to the system, Or it is desirable that it is defined as a fixed value.

  The synchronization signal transmission pattern in the above-described example is defined by, for example, a TTI number and a Sub-frame number at which P-SCH and S-SCH are transmitted.

  According to the embodiments of the present invention, a base station apparatus, a mobile station, a wireless communication system, which can prevent the deterioration of S-SCH characteristics in an inter-station synchronization system and reduce the processing load of a mobile station in a cell search, A synchronization signal transmission method and a synchronization signal reception method can be realized.

  In addition, a base station apparatus, mobile station, radio communication system, and synchronization signal transmission method capable of flexibly adjusting the trade-off relationship between S-SCH characteristic degradation in an inter-station synchronization system and processing load on a mobile station in cell search In addition, a synchronization signal receiving method can be realized.

  In the above-described embodiment, an example in a system to which Evolved UTRA and UTRAN (also known as Long Term Evolution, or Super 3G) is described, but the base station apparatus and communication control method according to the present invention is as follows. The present invention can be applied to all systems using orthogonal frequency division multiplexing OFDM (Orthogonal Frequency Division Multiplexing) in the downlink.

    Although the present invention has been described with reference to particular embodiments, the embodiments are merely illustrative and those skilled in the art will appreciate various variations, modifications, alternatives, substitutions, and the like. . Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be realized by hardware, software, or a combination thereof. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

  This international application claims priority based on Japanese Patent Application No. 2007-006429 filed on January 15, 2007, the entire contents of which are incorporated herein by reference.

Claims (7)

A base station apparatus that communicates with a mobile station using a OFDM scheme in a downlink in a wireless communication system,
Sequence selection means for selecting one first synchronization signal sequence from a plurality of first synchronization signal sequences;
A transmission pattern selection means for selecting one of the transmission pattern from a plurality of transmission patterns for transmitting the first synchronization signal and a second synchronization signal,
Transmitting means for transmitting the first synchronization signal and the second synchronization signal according to the selected one transmission pattern ;
Ru with a group Chikyoku equipment. Before Symbol a first sync signal sequence and the previous SL one transmission pattern is selected based on the ID of the cell, the base station apparatus according to claim 1. Before SL first synchronization signal sequence and the one transmission pattern is selected to be different from the first sequence of synchronization signals and transmit pattern used is adjacent base station apparatus, according to claim 1 or 2 The base station apparatus as described in . A row intends mobile station communications using an OFDM scheme in the base station apparatus a downlink in a wireless communication system,
A receiving unit that will receive the first synchronization signal from the base station apparatus,
Sequence acquisition means for acquiring the type of sequence of the first synchronization signal;
Transmission pattern acquisition means for acquiring transmission patterns of the first synchronization signal and the second synchronization signal;
The type of sequence in the first synchronizing signal, based on the transmission pattern of the first synchronization signal and the second synchronization signals, detection means for detecting a set of cell ID or cell ID,
That having a transfer Dokyoku. Before Symbol transmission pattern acquisition means, based on at least one of the first receiving space and a second synchronization signal information element of the synchronization signal, the transmission of the first synchronization signal and the second synchronization signal pattern to get, mobile station of claim 4. A synchronization signal transmission method executed by a base station apparatus that communicates with a mobile station using a OFDM scheme in a downlink in a wireless communication system,
A sequence selection step of selecting one first synchronization signal sequence from a plurality of first synchronization signal sequences;
A transmission pattern selection step of selecting one transmission pattern from a plurality of transmission patterns for transmitting the first synchronization signal and a second synchronization signal,
A synchronization signal transmission method comprising: a transmission step of transmitting the first synchronization signal and the second synchronization signal according to the selected one transmission pattern . A synchronization signal receiving method rows intends mobile station communication is performed using the OFDM scheme in the base station apparatus a downlink in a wireless communication system,
A receiving step that will receive the first synchronization signal from the base station apparatus,
A sequence acquisition step of acquiring a sequence type of the first synchronization signal;
A transmission pattern acquisition step of acquiring transmission patterns of the first synchronization signal and the second synchronization signal;
Same that Yusuke and types of sequences of said first synchronizing signal, based on the transmission pattern of the first synchronization signal and a second synchronization signal, and a detection step of detecting a set of cell ID or cell ID Period signal reception method.

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