Selection diversity combining with multiple antennas for MM-wave indoor wireless channels

In this paper, we present predetection and postdetection combining schemes for selection diversity reception with multiple antennas for millimeter-wave indoor wireless radio channels, For those combining schemes, a reduction in complexity Is achieved by limiting the number of combined signals to small values and by increasing the number of received signals, Bit error rate (BER) performance of binary phase shift keying (BPSK) with predetection combining of selected signals (CSS) and BER performance of differential BPSK with postdetection CSS are analyzed for slow fading and Rayleigh-distributed envelope maximal ratio combining of signals that statistics, Predetection comes from a single group or several groups of diversity channels as well as postdetection combining of received signals for groups of channels are considered, In comparing predetection combining with groups (PCG) and predetection combining of the best signals (PCB); we observe that the required signal-to-noise ratio (SNR) for achieving a certain BER is approximatively the same (with PCG having a slight advantage of 0.5 dB) for a given number, N, of diversity channels and L combined signals, Furthermore, PCG is equivalent to PCB for L = N since both techniques then correspond to conventional predetection maximal ratio combining (MRC), PCG and PCB are also equivalent when L = 1 as both schemes then correspond to conventional selection combining, A small degradation of approximately 2 dB in the required SNR is observed when postdetection diversity reception with groups (PDG) is used instead of PCG, For L = N, PDG reduce to post detection MRC, Because the time variations on some channels may be fast enough to preclude the implementation of coherent detection, the PDG technique is considered more suitable than PCB or PCG for indoor wireless communication systems operating in the mm-wave band.