在中继端运动与静止两种情况下分析了一个两用户放大转发协同通信系统的误码率(symbol-error-rate,SER)性能。首先得到M-PSK调制下的SER封闭表达式与相应上界,以此提出一个最优功率分配方案(optimum power allocation,OPA),目的是使得SER最小,然后讨论了在最优与等功率分配(equal power allocation,EPA)两种方案下中继按照椭圆拓扑运动时对SER的影响。EPA方案下,精确最优中继位置恰在源端与目的端的中点处,但是在OPA方案下最优位置却离目的端更近,并且,无论中继端运动还是静止,OPA方案都能得到比EPA更好的SER性能。
The symbol-error-rate (SER) performance is analyzed for a two-user amplify-and-forward cooperative communication system when the relay is movable and immoveable. By making use of M-PSK modulation, a closed-form SER formulation and corresponding upper bound are derived. Then the approximately optimum power allocation (OPA) method is given to minimize the SER performance. With the OPA and equal power allocation (EPA) method, the influence of relay location on SER is discussed by making use of a simple ellipse topology. Exact optimum relay location is the mid-point between the source and destination with EPA, while it is near the destination with OPA case. Furthermore, the OPA method outperforms the EPA case with a SER performance improvement whether the relay is moveable or not.