Decision of Transmit Relays and Transmit Power of Double Opportunistic Transmit Cooperative Relaying System in Rayleigh Fading Channels

摘要

Recently, cooperative diversity has been introduced to wireless ad-hoc networks for power saving and for diversity gain over fading channel. The space diversity gain is obtained from the multiple copies of signals from the several cooperating relays. Consequently this diversity gain saves the power of the networks. However, a receiver generally has fixed number of branches at a destination. Therefore the excess number of transmit relays does not contribute to the performance improvement, and only waste the network power and radio resources. Therefore, we propose a method which is adjusting the average number of transmit relays, and controlling the transmit power of the relays locally to satisfy the required performance in double opportunistic transmit (DOT) relaying system. Numerical analysis shows that average number of transmit relays decreases with the increase of threshold and vice versa. And we noticed that the transmit power of relays for the required system performance can be controlled locally.