用Duffing振子阵列解调微弱π/4-DQPSK信号

Using the Duffing oscillator arrays to demodulate the weakπ/4-DQPSK signal

首次提出了微弱π/4-DQPSK信号Dumng振子阵列的解调算法,并用计算机对此算法进行了相应的仿真验证,同时还创造性地提出了星座图重叠划分,功率谱熵计算阵列和Dumng振子码元分界点搜寻器。先将π/4-DQPSK星座图的8个点划分成相重叠的四个区域,然后用功率谱熵来判定不同区域内Dumng振子的不同响应,最后依据当前时刻Duffing振子阵列的不同响应来断定所传送的数字信息。计算机仿真结果表明,本算法切实可行,在高斯信道中解调信噪比最低可达-15.6 dB。

Concerning the high BER and the phase ambiguity of the π/4-DQPSK signal＇s traditional demodulation method in low SNR, the demodulation method based on duffing oscillator arrays was studied. π/4-DQPSK signal＇s 8 phases correspond with the 8 points in its constellation figure, firstly, the constellation is divided into 4 overlapping regions and each region contains 3 phases, then we put the π/4-DQPSK into the Duffing oscillator arrays as the tested signal, we can know which regions the current π/4-DQPSK is in from he power spectrum entropy of Duffing oscillator arrays＇s output signal. Later, use a set of decision rules to decide which point the current signal belong and recovered the I, Q branch signals. Finally, use the differential decoding and parallel /serial conversion to recover the digital information which we sent out. The simulation results show that this demodulation method is suitable for demodulating the π/4-DQPSK signal in Gaussian channel and Rice channel.