Effect of User Mobility in Coded Cooperative Systems with Joint Partner and Cooperation Level Selection

In cooperative diversity systems, single antenna nodes may share their antennas to achieve a performance comparable to multi-antenna systems. Cooperative diversity is efficiently provided by the coded cooperation algorithm (Hunter and Nosratinia, 2002) where users cooperate by mutually transmitting their FEC-coded data. This paper studies the effect of user mobility on the outage probability performance of coded cooperation with two users. For this study the authors assumed that users do not always move and that for moving users, fading channel characteristics depend on the motion speed. Considering these two mobility factors, scenarios were defined for which the outage probabilities were analytically derived. The effects of user speed and the level of cooperation are further investigated by simulation. Finally a simple method for the dynamic selection of partners required for successful cooperation by adapting the cooperation level was proposed and discussed the effect of mobility and transmission power on the performance of this method.