无循环前缀正交频分复用多址上行链路处理算法

Parameters Estimation and Signal Detection for OFDMA Uplink Without CP Based on Time Oversampling

提出了一种无循环前缀正交频分复用多址(OFDMA)上行链路发射信号帧结构,为消除因无循环前缀造成的正交频分复用(OFDM)符号块间干扰(IBI),接收端对接收信号进行时域过采样,对过采样后OFDM符号中无符号块间干扰部分采用最小均方误差(MMSE)算法进行信号检测.采用最大似然估计算法进行时间同步和频偏参数估计,利用伪随机(PN)序列的相关性对信道参数进行估计.仿真证明:本文提出的频偏信道参数估计算法具有良好的抗噪特性、衰落信道适应性和高的估计精度,而MMSE算法也具有较好的误比特率性能.

A transmit signal frame structure for orthogonal frequency division multiple access （OFDMA） uplink without cyclic prefix（CP） was proposed. In order to combat the inter-block interference （IBI） of OFDM symbol by reason of without CP, this paper presented a new signal detection scheme for OFDMA uplink without CP, which is based on time oversampling. The proposed signal detection scheme adopts ordered successive detection based on a minimum mean square error （MMSE） criterion to treat with the part of orthogonal frequency division multiplexing （OFDM） symbol without IBI. A maximum-likelihood timing synchronization and carrier frequency offset estimation algorithm was proposed to obtain timing synchronization and the carrier frequency offset parameter. The time domain channel estimation algorithm in this paper is based on correlation of PN sequence. The simulation results demonstrate the carrier frequency offset and channel estimation algorithm can get more accurate parameters estimation, meanwhile it is immune to the noise and adapts to the fading channel, the MMSE signal detection algorithm can provide better bit error rate performance.