Comparison of space-time architecture performance for UMTS under time-varying Rayleigh fading channel

Recent advances in space-time signal processing have enabled the realization of multiple-input multiple-output (MIMO) communication systems. It is highly probable that MIMO architectures will be important contenders for the next generation mobile communication systems (3G/4G). We investigate a receiver comprising two main processing blocks: a MIMO processor providing the spatial diversity and a UMTS processor. These are combined to produce a space-time UMTS (ST-UMTS) receiver system. Two ST-UMTS uplink receiver architectures are proposed. In the first configuration, the MIMO processor precedes the UMTS processor. In the second configuration, the MIMO processor operates after the UMTS processor. We compare their BER performance through the use of computer simulations. The BER performance curves show a small performance difference between the two architectures. Analysis into other aspects, such as capacity and MAI handling capability, is needed to compare the performance of the two architectures. However, both architectures present a solution to enhancing the data throughput of existing UMTS systems.