一种改进的OFDM自适应调制方法

An improved adaptive OFDM modulation method

为了使信号的传输更加准确和快速,建立了自适应OFDM系统。对该系统的信道功率和比特进行更加合理的分配,各个信道增益不一样导致衰落不一样,采用传统的固定调制方式,则衰落往往由最差的信道决定不能很好的利用信道资源。首先,根据已经有一些经典算法分析其缺点和实用范围,最后以Fischer算法为基础对其改进。首先,依据确定信道信息对功率、比特基于误码率原则进行分配,接着对于功率分配进一步优化。即联合功率和比特分配。然后已有的算法和改进的算法在同一信道下比特和功率分配进行比较,说明改进算法的比特和功率分配的更加合理。最后仿真了信噪比与误比特率的关系曲线图,结果表明:在信噪比为16-24d B时改进算法的误比特率能够比原有的算法误码率降低5倍,甚至更好。基本满足人们通信过程中稳定性、速度快、服务质量等要求以外更加保证误比特率,更好满足人们愿意。

In order to make more accurate and fast, the transmission of signals adaptive OFDM system is established. Channel power and bits of the system more reasonable distribution of each channel gain different lead to decline, the traditional way of fixed modulation, decline is often determined by the worst channel can not make good use ofth~ channel resources. First of all, according to the already some classic algorithms to analyze its defects and practical scope, the final Fischer algorithm based on its improvement. First of all, according to the determined channel information to distribution of power and bits based on the principle of error rate, and then further optimized for power distribution. The joint power and bit allocation. And then have some algorithm and improved algorithm under the same channel bit and power allocation, improved algorithm