多误码率固定速率OFDM自适应调制比特功率分配方法

Bit and power allocation of multiple bit error rate OFDM adaptive modulation

一些应用中需要多误码率的固定速率OFDM自适应调制。本文首先对该多载波自适应调制需求中的比特功率优化分配问题建模,并进一步限定各OFDM子信道采用正交幅度调制(QAM),基于子信道调制比特的任意正实数和无限粒度假设详细分析了子信道集合划分和比特功率分配问题,由此得到一种实用的次最优子信道集合划分和比特功率分配方法。分析和仿真表明由于可得到比特分配的闭式表达,因此该方法计算复杂度低,且性能良好,是一种实用的多误码率固定速率OFDM自适应调制比特功率优化分配方法。

Multiple bit error rate OFDM adaptive modulations are needed in some applications. Firstly, the problem of optimal bit-power allocation is modeled, and then with the use of QAM in OFDM subchannels and based on the assumptions of positive real number and infinite-granularity for modulated bits of subehannels, the problem is discussed and analyzed, and finally a suboptimal sub- channel sets partitioning and bit-power allocating method is developed. Analysis and simulations show that the algorithm performs well and is of low complexity since the bit allocating resuhs can be represented in close-form expression, so it can be concluded that it is a practical optimal bit-power allocating method for multiple bit error rate OFDM adaptive modulation.