Performance Research On Wireless Relay Communication System Over Cascaded Channels

The paper studies the performance of dual-hop transmissions with fixed gain relaysand relays selection in dual-hop communication system. In mobile-to-mobile (M2M)wireless communication system, both the transmitter and receiver are in motion andtheir antennas are relatively at lower elevations invalidating the conventional fadingmodels. Cascaded fading channel model is accepted to be a more realistic description ofthe M2M channel.Firstly, we analyze the performance of a relay selection scheme with thedecode-and-forward (DF) protocol. Only the “best” relay, which satisfies an index ofmerit, is selected. The outage probability of the destination is derived, and compareswith other channels models. Secondly, the end-to-end performance of dual-hoptransmissions with fixed gain relays over Generalized-K fading channels is studied, newclosed-form expressions are derived for the moments of the end-to-end signal-to-noise(SNR). Useful performance criteria are studied; the average end-to-end SNR andthe amount of fading, which are expressed in closed form, the end-to-end approximatecapacity and its up-bound are also obtained. Furthermore, the closed-form expression isobtained of for the gain of semi-blind relays over cascaded Generalized-K fadingchannels. Finally, in the dual-hop relay communication system, DAF(differentialamplify-and-forward) scheme is introduced, and the outage probability expression ofthe destination is derived.