Abstract
This work proposes novel techniques toward the design of optimal pilot sequences to perform channel estimation in block transmission systems over wideband frequency selective wireless fading channels. The framework developed is based on minimization of the Bayesian Cramer-Rao bound (BCRB) for the mean squared error (MSE) of the channel state information (CSI) estimate. Optimal pilot signals are determined for the four predominant classes of block transmission systems, viz. single carrier zero padding (SC-ZP), multi-carrier zero padding (MC-ZP), single carrier cyclic prefix (SC-CP) and multi-carrier cyclic prefix (MC-CP) systems. This makes the techniques developed general in nature and thus applicable in a wide variety of block transmission systems. As part of this study, succinct expressions and results are also derived to characterize the error rate performance, incorporating also the effect of CSI estimation error resulting due to the proposed algorithms. Finally, numerical results obtained via Monte-Carlo simulation are presented to illustrate and compare the CSI acquisition performance of optimal pilot designs with that of conventional designs and also validate the theoretical analysis for the error rate performance.
Highlights
The advent of 4G and 5G technologies coupled with the increase in popularity of multimedia rich applications is driving the current demand for high data rates in wireless networks
Results are not presented for the bit error rate (BER) performance in block transmission systems incorporating channel state information (CSI) estimation error. To address these issues that have not been tackled in the existing literature, this paper proposes a single framework for the design of optimal pilot signals in single carrier zero padding (SC-zero padding (ZP)), single carrier cyclic prefix (SC-cyclic prefix (CP)), multi-carrier zero padding (MC-ZP) and multi-carrier cyclic prefix (MC-CP) block-transmission formats
Since the proposed algorithm is based on minimizing the Bayesian Cramér-Rao bound (BCRB) that represents a lower bound on the mean squared error (MSE) of channel estimation, it yields the best possible performance
Summary
The advent of 4G and 5G technologies coupled with the increase in popularity of multimedia rich applications is driving the current demand for high data rates in wireless networks While this can be achieved via transmission over channels with ever increasing bandwidths, the high delay spreads and the resulting frequency selectivity of wireless channels, which in turn lead to significant distortion due to inter symbol interference (ISI), pose a severe challenge toward the practical implementation of such systems. Results are not presented for the BER performance in block transmission systems incorporating CSI estimation error To address these issues that have not been tackled in the existing literature, this paper proposes a single framework for the design of optimal pilot signals in SC-ZP, SC-CP, MC-ZP and MC-CP block-transmission formats. Worth noting is the fact that while SC-CP transmission achieves the full multi path diversity only for large block sizes, SC-ZP systems, in stark contrast, are able to do so for an arbitrary block size
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