自适应变速率MQAM在VHF/UHF频段的应用研究

Research on Application of Adaptive Variable-Rate MQAM in VHF/UHF Band

从电磁波在无线移动信道的传播特点入手,分析了无线移动衰落信道对数字信号传输的影响,并设计了一个在VHF/UHF频段以自适应变速率MQAM为核心技术实现高频带利用率的通信系统。该系统通过检测接收信号能量来调整调制电平数的方法,可以克服诸如“检测误码控制自适应调整”等方法存在的调整滞后的问题。在无线信道中的仿真表明,该系统的有效频带利用率大于3.2bit/s/Hz,高于该频段现有无线数据通信系统的相应指标。

Based on the characteristics of electromagnetic wave＇s propagation over mobile radio channels, the effect of mobile radio fading channels on data transmission was analyzed, Then a communication system working in VHF/UHF band was designed to make high bandwidth efficiency. The core technology of the system is adaptive variable-rate MQAM. It adjusts the modulation level by means of detecting the energy of the received signal, so the problem of adjustment delay could be overcome. The problem exists in methods such as adaptive adjustment by symbol error detection. The results of wireless-channel simulation show that the bandwidth efficiency of this system is more than 3.2bit/s/Hz, which is better than the corresponding index of existing wireless data communication systems in VHF/UHF band.