分布式多小区联合传输中的自适应反馈比特分配

Adaptive Feedback Bit Allocation in Distributed Multi-cell Joint Transmission

基于有限反馈的分布式多小区联合传输系统,提出一种自适应比特分配方案.通过分析有限反馈造成的系统总速率损失,得到速率损失近似上界与用户分配给各信道的反馈比特数的闭式函数关系.根据该闭式表达提出了一种自适应反馈比特分配方案,该方案基于不同信道的反馈比特数对速率的影响,在用户各信道之间自适应分配反馈比特数,显著减小了有限反馈带来的速率损失,提高了系统速率.算法复杂度分析表明,该方案无需增加额外的周期性反馈信息,也无需巨大的计算量,易于在实际系统中实现.仿真结果验证了该方案的性能.

In this paper, we propose an adaptive feedback bit allocation strategy for distributed multi-cell pre-coding systems with limited feedback. By analyzing the rate loss of multi-cell joint transmission caused by limited feedback, we provide an approximate upper bound as a function of allocated feedback bit for each channel. Based on this rate loss, an adaptive feedback bit allocation strategy is proposed. The strategy effectively reduces the rate loss due to limited feedback, and thus significantly increases the system rate. Without additional periodical feedback and heavy computation overhead, the proposed strategy is feasible in real systems. Good performance has been shown in simulation.