衰落环境下B3G移动通信系统有效信道容量优化的研究

研究Rayleigh衰落信道下B3G移动通信系统有效信道容量的优化问题。首先,回顾了有衰落时的Shannon信道容量,并根据信道信息确定最佳功率控制方案;然后,根据系统给定的掉话概率Pout确定最佳的干扰门限值α0*,使系统总干扰最小;最后,在定义系统有效信道容量概念的基础上利用拉格朗日乘子法推导出最大化系统有效信道容量的发射数据速率。研究表明,α0*与功率控制干扰因子ρ、接收机可分辨出的路径数M以及系统掉话率等有关。数值仿真结果证明了理论推导的正确性,并得出结论:对于给定的α0*,只要选取M≥4,功率控制干扰因子ρ≤0.5,系统有效信道容量就存在全局最大值。

A Study on the Effective Channel Capacity for B3G Mobile Communication Systems Under the Rayleigh Fading Environments

This paper studies the optimization of the effective channel capacity of the B3G mobile communication system under the Rayleigh fading environments.Firstly,the results for Shannon capacity of fading channels with channel side information are reviewed,where the capacity is achieved by using an optimal power control scheme.Secondly,an optimal interference threshold α*0 is set for a given system outage probability Pout to minimize the total interference.Finally,the effective channel capacity of the system is defined and a transmission data rate is determined with the Lagrangian multiplier method to maximize the effective channel capacity.It is shown that α*0 is dependent on the interference factorρ,the number of diversity paths identified by the receiver M,and the outage probability of the system.Numerical results are provided to validate the theoretical deductions.We conclude that the total effective channel capacity will be maximized as long as M≥4 and ρ≤0.5 for a proper value of α*0.