Research On Compressed Sensing And Its Application In60GHz Channel Estimation

The growing demands for high-speed data streams and broadband wireless services have significantly driven the worldwide researches on60GHz millimeter-wave frequency band communications, which is mainly designed for the wireless accessing network such as the Pico-cellular mobile systems, the wireless local area networksand wireless personal area networks. In order to achieve the targeted ultra-high throughput in the next generation WLAN systems, the new WLAN/WPAN standards are currently developed by the IEEE802standardization committee. The main motivation for60GHz millimeter-wave communications is the availability of abundant unauthorized spectrum resources, which enables the realization of Gbps transmission as well as the worldwide broader market of60GHz products and therefore attracts a large number of famous manufacturers.We may notice from the60GH millimeter-wave channels that, dramatically different from the narrow-band systems, except for the overall sparsity of channel MPCs that attenuated by following an exponent decay function, the local sparse property introduced by the cluster phenomenon may greatly facilitate the practical designs of efficient reconstruction algorithm. Based on the cluster identification results, the local sparsity can be observed, i.e. the few nonzero coefficients occurring in each cluster, which may be are referred to as the block cluster-sparsity. By explicitly taking such a specific block structures into account, both in terms of the recovery algorithm and in terms of the measure that are used to characterize the performance, a novel cluster sparsity compressive sensing (CS-CS) algorithm for60GHz channel estimation is proposed. The reconstruction performance (i.e. reconstruction error and iterative convergence) is compared with the classical ROMP algorithms based on the extensive experimental simulations. It has been shown that the proposed CS-CS algorithm can significantly enhances the accuracy of60GHz channel estimations, and simultaneously exhibits a much faster iteration behavior. The advantage of such a new CS-CS may be essentially attributed to the full exploitation the specific cluster-sparsity, except for the overall sparsity as in conventional sense.The remainder of this paper is organized as follows. In Section I, we discussed60GHz channeling model and the simulated60GHz millimeter CIRs, for both the line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios in typical short-range indoor applications, have been plotted. In Section Ⅱ, we highlighted that the60GHz multipath channel is relatively special, which may show quite different characteristics and we briefly introduced the classical CS theory. In Section Ⅲ, we analyze the60GHz multipath channel and then draw the conclusion that Attributed to the enormous emission bandwidth (typically surpassing2GHz) and the resulting fair time resolution as well as the involved many objects in operation environments, the60GHz propagation is always intensive multipath channel, which also assumes the received resolvable MPCs arrive in clusters. That is, the rays within a cluster (or a group) may have independent phases as well as independent amplitudes distribution whose variances decay exponentially with cluster and rays delays. In Section IV and V, block sparsity embodied by the multiple clusters is developed, and on this basis, the more competitive cluster-sparsity based compressed sensing algorithm for the channel estimations of60GHz millimeter-wave is developed. Then the comprehensive experimental simulations and comparative performance analysis are provided. Finally, we conclude the whole investigation in Section VI.