METHOD FOR CAPTURING CONTROL LOGIC CHANNEL USED IN CHINA MOBILE MULTIMEDIA BROADCASTING SYSTEM

摘要

A method for capturing Control Logic Channel (CLCH) used in China Mobile Multimedia Broadcasting (CMMB) system is disclosed in the present invention. The method comprises the following steps of: detecting a complex pseudorandom sequence scrambled on Orthogonal Frequency Division Multiplexing (OFDM) symbols of a current time slot in a variety of complex pseudorandom sequences by using a complex pseudorandom sequence carried in a discrete pilot frequency position firstly; after accurately identifying the complex pseudorandom sequence used by the current time slot, re-descrambling transmission indication information by using the complex pseudorandom sequence; after performing corresponding processes of soft demodulation and repetitive decoding according to the modulation code characteristic of the transmission indication information, detecting the transmission indication information; and then starting a corresponding time slot logic number accumulator by means of the time slot logic number comprised in the detected transmission indication information, until the number 0 time slot is captured. Applying the method of the present invention, the number 0 time slot corresponding to the Control Logic Channel can be captured reliably, control information of the broadcast system can be resumed accurately and the method can be realized easily.