Four branch diversity measurements at 1.7 GHz for indoor wireless communications

Wireless communication systems must operate in buildings where multipath propagation and the dynamic environment create severe signal fading which necessitates the use of diversity techniques. The authors directly compare three techniques at 1.75 GHz based on envelope fading measurements in a university building using a 4-branch receiver. The variations of the envelope fading distributions with and without diversity are measured during numerous one minute intervals and the effect on the average error rate performance of differential phase shift keying modulation (DPSK) is presented. Results based on cumulative distribution functions indicate that the difference between the worst case envelope fading and the average statistics over all measurements is significant. The results suggest that variations in envelope fading statistics and diversity performance should be considered in a worst case link design and that 2 and 4-branch diversity is effective under this worst case fading