基于多种调制方式的超宽带空时网格编码

为结合多入多出系统和超宽带的优点来实现高速高效的传输,将空时编码技术应用于超宽带系统中,讨论了基于脉冲位置调制(PPM:Pulse-Position Modulation)、脉冲幅度调制(PAM:Pulse-Amplitude Modulation)以及双正交调制3种不同方式的超宽带空时网格编码方案。考虑在发送和接收端已知信道状态信息,分别建立了3种方案的发射接收模型。仿真结果表明,在高斯信道和IEEE802.15.3a信道条件下,采用PPM的超宽带空时网格编码方案的性能都远优于其他两种方案,当信噪比为8dB时,误码率降低10~100倍。进一步考虑在存在多用户干扰条件下,该系统性能随用户数的增加而下降。

Space-Time Trellis Coding for UWB Systems Based on Different Modulations

To exploit the advantages of both UWB(Ultra WideBand) and MIMO(Multiple Input Multiple Output),STTC(Space-Time Trellis Codes) is applied to UWB systems, and STTC UWB systems with different modulations are discussed.Models of three schemes employing PPM(Pulse Position Modulation),PAM(Pulse Amplitude Modulation) and biorthogonal modulation are set up separately,and it is assumed that the channel state information can be obtained at both transmitter and receiver.Simulation results show STTC UWB with PPM can achieve much better performance than the others under both Gaussian and IEEE802.15.3a channel.The bit error rate of STTC UWB with PPM is 10~100 times lower than the other two while the signal to noise ratio is 8 dB.So the scheme employing PPM is preferred and we further find when MUI(Multi User Interference) is considered the performance degrades when the number of users increases.