【摘要】 该文从最大化信道容量(数据通过速率)的目标出发,基于简化的QAM调制统一误比特率表达式,用Lagrange乘数法给出了给定发送功率和QoS要求约束条件下最优功率和调制方式分配的闭式解,并利用Obit分配排除衰落大的子载波,成功地解决了实际的正功率和调制方式分配的要求。最后使用连续调制离散化近似(O,QPSK,16QAM和64QAM)的方法逼近基于连续调制优化的分配结果,仿真结果说明这种离散逼近的方法带来的信道容量损失可以忽略,并且能够保证给定的QoS要求,这种方式适合于可变速率的业务。更多还原

【Abstract】 In this paper, the optimization of channel capacity (equivalent to data throughput) is proposed for variable-rate service, which is solved with the Lagrangian multiplier method based on a simplified BER formula for m-QAM modulation. The closed-form solution for the optimization problem is given and the practical constraint of positive power and modulation mode allocation is solved by null transmission on those deep-faded subcarriers. Finally discrete modulation mode (0, QPSK, 16QAM and 64QAM) is used to approach the optimally allocated continuous modulation mode, and simulation results demonstrate that the capacity loss from this approaching is negligible and QoS is guaranteed.更多还原