Data generation apparatus, data generation method, base station, mobile station, synchronication detection method, sector identification method, information detection method and mobile communication system

Abstract

[Problems] To reduce a cell search process including sector identification without increasing a load on a transmission / reception device.[Means for Solving Problems] A synchronization channel (SCH) contained in a down link of a multi-carrier mobile communication system is multiplied by a sector unique code and a cell unique code (step S1). The multiplication result is allocated to a sub-carrier on the frequency axis (step S2) and subjected to a spread process and an IFFT process (steps S3, S4). Furthermore, GI is inserted and D / A conversion are performed (steps S5, S6). A multi-carrier is transmitted from a directivity antenna of each sector (step S7). A reception side identifies the SCH position by the self-correlation method or the mutual correlation method and performs the FFT. After this, the reception side simultaneously performs identification of a sector by detecting a sector unique code and acquisition of cell unique information by demodulating a cell unique code.

Description

TECHNICAL FIELD[0001]The present invention relates to mobile communication of the E-UTRA (Evolved-UTRA) standard adopting a multicarrier communication scheme, and more particularly to a data generation apparatus, data generation method, base station, mobile station, synchronization detection method, sector identification method, information detection method and mobile communication system for generating data of a synchronization channel (SCH) included in a downlink (transmission) signal.BACKGROUND ART[0002]In recent years, the third generation mobile communication (3G) including W-CDMA systems has been in widespread use on a worldwide basis. Currently, the fourth generation mobile communication (4G) has further been considered to implement communication rates of 100 Mb / s to 1 Gb / s on downlink. However, it is not easy to completely shift from 3G to 4G. Therefore, attention is directed toward E-UTRA (Evolved-UTRA) for increasing the rate in communication using a frequency band of 3G w...

AI Technical Summary

Benefits of technology

[0082]According to the invention, by a sector common code being multiplied by a sector specific code, it is possible to identify a sector only by despreading and correlation detection using the SCH without using a pilot channel. Accordingly, with respect to sector identification, the need is eliminated for despreading and correlation detection processing using a pilot channel, and it is possible to reduce the capacity of memory to be used in correlation calculation using the pilot channel.

[0083]Further, since the SCH is multiplied by the sector specific code, it is possible to eliminate interference between sectors even in a boundary of the sectors. Furthermore, it is possible to obtain the effect of enhancing anti-fading characteristics by randomizing effect produced by code multiplication. It is easy to increase the number of sector specific codes (orthogonal codes) assigned for each sector according to an increase in the number of sectors, and to respond to the sector configuration flexibly.

[0084]Moreover, when the number of subcarriers of the SCH is adequate (to multiply by the cell specific code of the SCH), it is also possible to directly identify a cell ID only by the SCH. In this case, the cell search processing including sector identification is completed by 2-step processing using only the SCH (2-step cell search), and the search time can be reduced as compared with the conventional 3-step cell search.

[0085]Further, by devising structures, contents and arrangements on the frequency axis of a cell specific code and sector specific code to multiply, it is possible to prevent the sector specific code and cell specific code from imposing an adverse effect on each other, and to suppress a decrease in information transmission accuracy. Furthermore, each information can be demodulated independently (i.e. in parallel processing). By this means, it is possible to reduce the processing time of a cell search including a sector search.

[0086]In other words, a 2m-chip code is generated by combining two orthogonal m-chip codes, the m-chip code is used for sector identification, the other m-chip code is used for identification of cell specific information, and further, the cell specific information is transmitted as phase difference information between subcarriers (that are more preferably adjoined on the frequency axis) multiplied by a sector specific code element of the same value. It is thereby possible to efficiently transmit the sector specific information and cell specific information, while the receiving side can divide and extract both of the information with efficiency.

[0087]Further, in the cell search method of the invention, it is possible to complete the cell search by timing detection of the SCH (first step) on the time axis by an auto-correlation method using periodicity of the SCH or cross-correlation method using time waveforms of replica codes of the sector specific codes, and identification of a sector ID and cell ID (second step) based on information on the frequency axis. Accordingly, it is possible to reduce the search process as compared with the conventional 3-step cell search. Further, correlation detection using a pilot channel is required only in demodulating a data channel while being not required in a cell search, and it is thereby possible to achieve reductions (such as a reduction in memory capacity and the like) in loads of hardware used for correlation calculation of the pilot channel. Furthermore, since the sector specific code is multiplexed on the SCH, with respect to sector identification, it is possible to obtain effects of having resistance to interference between sectors and fading. However, when the number of subcarriers is not adequate, the cell ID cannot be identified directly only by the SCH, and there may be a case that cell ID group information is only detected. In this case, the cell ID can be identified by implementing despreading and correlation detection using a pilot channel as processing of the third step.

Problems solved by technology

However, it is not easy to completely shift from 3G to 4G.

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