摘要
针对采用成形偏移QPSK(SOQPSK)调制的短帧突发通信系统在大频偏条件下的载波恢复问题,提出了一种导频和解调软信息联合辅助的载波同步算法.该算法首先利用少量的导频序列进行载波偏差粗估计,然后在粗估计值附近的一定区间内进一步细搜索,以SOQPSK解调软信息均方值最大化为准则,得到精确的载波估计值.仿真结果表明,在信噪比大于0dB、导频序列长度为30bit时,该算法能够以较低的运算复杂度校正小于符号速率一半的载波频偏,克服相位模糊,实现有效的载波同步,获得接近最佳相干解调的误比特性能.在误比特率为10-2～10-5时,信噪比损失在0.3dB以内.
To solve the carrier recovery problem with large frequency offset in short burst communication systems using shaped-offset quadrature phase shift keying（SOQPSK）, a joint pilot and demodulation soft information assisted carrier synchronization algorithm is proposed. First, coarse synchronization based on a few short pilot sequences is carried out. Then, further fine search is done around the coarse synchronization estimation region. The precise carrier synchronization parameters are obtained based on the maximum- mean-square soft output of SOQPSK. Simulation results show that at Eb/N0 ≥ OdB the proposed algorithm can eliminate large carrier offsets by as much as half the symbol rate, resist phase confusion and achieve effective carrier synchronization with 30 pilot bits and low computation complexity, achieving a BER performance which is very near the optimal coherent demodulation performance. When BER is in the region of 10^-2～10^-5, SNR degradation is below 0.3 dB.
出处
《西安电子科技大学学报》
EI
CAS
CSCD
北大核心
2013年第4期14-20,101,共8页
Journal of Xidian University
基金
国家自然科学基金资助项目(60902039
61271175)
中央高校基本科研业务费专项资金资助项目(K50511010014
K5051201043
CHD2011JC088)
长安大学基础研究支持计划
关键词
SOQPSK
导频
软信息
载波同步
SOQPSK
pilot
soft information
carrier synchronization
