- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
This paper addresses the problem of initial acquisition in code division multiplexing employing Walsh-Hadamard code (WHCDM). Unlike pseudo-noise codes used in directsequence spread spectrum communications, Walsh-Hadamard code has many side lobes in its autocorrelation function. Wellknown initial acquisition schemes for direct-sequence spread spectrum communications, therefore, cannot be applied to WHCDM. In order to solve this problem, we propose an initial acquisition scheme for WHCDM with a novel approach. It detects the symbol timing on the basis of not the autocorrelation function of WalshHadamard code but the energy variance of the signal after demultiplexing. The results of computer simulation confirm that the proposed scheme provides rapid acquisition.