Turbo multiuser detector with multimedia transmission for intelligent transportation systems

DS/CDMA system is one of the candidates to support multiuser multimedia service due to its many attractive properties for the wireless channel. In intelligent transportation systems, signals from moving vehicles are allocated in a same bandwidth. Therefore, the signals of the low-power users can be distorted by those of high-power users. To avoid this problem, turbo multiuser detector proposed for an intelligent transportation system. As a multimedia transmission strategy, a variable spreading length (VSL) approach is employed by assigning several spreading codes to distinguish each user with constant chip rate. The bit error rate of the proposed system is derived and simulated in both AWGN and Rayleigh fading channels. From the simulation results, it is confirmed that the bit error rate is affected by the number of multiple users rather than difference of each data transmission rate.