DefinePK

Abstract

Significance of properties of spreading codes in the performance of CDMA-based systems cannot be overemphasized. This paper investigates correlation properties and multiple-access performance of some m-sequences and Gold codes. The Gold codes were generated from appropriate combinations of preferred pairs of m-sequences, obtained from software implementation of linear feedback shift registers. The correlation properties of the codes were tested prior to their deployment in a multi-user spread-spectrum communication system. Software simulations were carried out on the system bit-error-rate performance for transmission of random QPSK symbols through the channel. Transmitted data were encoded using 31, 127, 511 and 2048-chip Gold codes. The system bit-error-rate was computed and analyzed for increasing number of interfering users. Simulation results show that under increasing load, bit-error-rate of the Gold codes exhibited no error floor or significant system saturation. The results show that certain Gold codes have better properties that make them excellent for multiple access applications.