基于比特对数似然比分集的WCDMA系统性能

Performance of WCDMA systems Based on Bit Log-likelihood Ratio Antenna of Diversity

研究比特对数似然比(BLLR)的天线分集是误比特率性能优于传统信噪比(SNR)天线分集的一种新技术,对组合空时分组码、2D-RAKE接收机和基于BLLR分集技术的MQAMWCDMA系统在相关MIMO Nakagami衰落信道上的误比特率性能进行蒙特卡洛仿真研究,并推导了接收相关的Nakagami衰落信道上采用BLLR检测的16QAM WCDMA系统平均误比特率的解析表达式。仿真结果表明,理论推导与仿真结果相吻合。对于BLLR的广义选择合并分集技术的系统误比特率性能优于SNR的广义选择合并系统;选取的可分离路径数越多系统性能越好,而平均路径强度的衰减速率越小,误比特率性能越好。

The antenna diversity based on bit log-likelihood ratio（BLLR） is a new technology which is better than that based on signal-to-noise ratio（SNR） in performance.The BER performance of MQAM WCDMA system combined with space-time block coding（STBC）,2D-RAKE receiver and bit log-likelihood ratio antenna diversity on correlated Nakagami fading channels has been investigated.Analytical expressions for the BER of 16QAM WCDMA system based on bit log-likelihood ratio approach over receiver correlated Nakagami fading channels is derived.Simulation results show that the scheme based on BLLR is superior to the scheme based on signal-to-noise ratio.The performance of WCDMA system becomes better with the increase of multipath components and multipath delay profile.