Tongxin xuebao (Jan 2012)
Cooperative multiple access broadcast transmission strategy and performance analysis in asymmetric two-way relay system
Abstract
In a two-way relay system where two nodes exchange information via a half-duplex relay,the achievable data rates of both directions are limited by the weaker link.When the two-way channel is asymmetric due to relay positioning or channel fading,the sum rate of the two-way relay system will suffer from severe degradation.In order to compensate for the performance degradation caused by the weaker l k,a novel three-time-slot cooperative multiple access broadcast strategy was proposed where the source node with better channel quality cooperatively transmitted with the relay node and each node transmitted at the maximum rate of each link.As a result,the weighted sum rate of the two-way relay system can be thus improved.The upper bound of the capacity for the new strategy and an achievable rate region with decode-and-forward protocol were derived.Time slot allocation and power allocation at the relay were optimized to achieve the maximum weighted sum rate.Simulation results show that the proposed strategy outperforms existing strategies under asymmetric channel conditions both in AWGN and Rayleigh fading channels.
