Pre- and Post-DFT Combining Space Diversity Receiver for Wideband Multi-Carrier Systems

The basic receive space diversity combining methods, i.e. Maximum Ratio Combining (MRC), Equal Gain Combining (EGC) and Selection Combining (SC), are studied in this work for Preand PostDFT combining wideband multi-carrier receivers. A common system model for both these schemes are devised. The outage and mean capacity and Frame Error Rate (FER) simulations show that Pre-DFT combining techniques performs quite comparatively in indoor scenario, while PostDFT combining performs far better in outdoor scenario. Compared to Pre-DFT combining schemes in indoor scenario, Post-DFT MRC and SC obtain an increment of 1.4 and 0.9 bps/Hz respectively in terms of 10% outage capacity. At 10−3 of FER, Post-DFT MRC obtains a gain 2 dB and 4 dB in required Signal to Noise Ratio (SNR) for indoor and outdoor scenario respectively. In contrary to performance degradation, Pre-DFT schemes require much less computational complexities and they are simpler to implement compared to Post-DFT schemes.