Efficient Channel-Estimation-Based Multiuser Detection for Underwater CDMA Systems
Efficient Channel-Estimation-Based Multiuser Detection for Underwater CDMA Systems
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DOI：
10.1109/joe.2008.2005355
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发表时间：
2008-10
影响因子：
4.1
通讯作者：
Eduard Calvo;Milica Stojanovic
中科院分区：
文献类型：
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作者：
Eduard Calvo;Milica Stojanovic
为降低高失真水下信道的最大似然检测器的复杂度，提出了一种基于循环坐标下降法的联合数据检测和信道估计的多用户检测算法。假设数据符号是可用的，它们被用来估计信道响应，而信道响应又被用来细化符号估计。自适应估计是使用最小均方误差作为整体优化标准。接收机是在多通道配置，它提供了必要的阵列处理增益的许多水下声通道。检测算法的复杂度与接收单元的数目成线性关系，并且不依赖于发射信号的调制电平。该算法已被测试，使用真实的数据在20 kHz频带的2公里浅水通道，表现出良好的效果。
Motivated by finding reduced complexity versions of the maximum-likelihood (ML) detector for highly distorted underwater channels, a multiuser detection (MUD) algorithm for joint data detection and channel estimation based on the cyclic coordinate descent method is proposed. Assuming that the data symbols are available, they are used to estimate the channel responses, which, in turn, are used to refine the symbol estimates. Adaptive estimation is performed using minimum mean square error as the overall optimization criterion. The receiver is implemented in a multichannel configuration, which provides the array processing gain necessary for many of the underwater acoustic channels. The complexity of the detection algorithm is linear in the number of receive elements and it does not depend on the modulation level of the transmitted signals. The algorithm has been tested using real data obtained over a 2-km shallow-water channel in a 20-kHz band, demonstrating good results.