A novel reduced-complexity soft decision (SoD)-aided detector is proposed for the recent concept of space-time shift keying (STSK), where the detector's achievable performance is capable of closely approaching tha...
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A novel reduced-complexity soft decision (SoD)-aided detector is proposed for the recent concept of space-time shift keying (STSK), where the detector's achievable performance is capable of closely approaching that of the optimal maximum a posteriori (MAP) detector. More specifically, we exploit a hybrid combination of the modified matched filtering concept and of reduced-complexity exhaustive search for the sake of reducing the MAP detector's decoding complexity. Furthermore, we extended this detector to support the class of generalized STSK (GSTSK) scheme that subsumes diverse multiple-input-multiple-output (MIMO) arrangements. The proposed reduced-complexity SoD-aided GSTSK detector also attains significantly lower complexity than the MAP detector while imposing only marginal performance degradation, which is in the range of 1-2 dB. As an optional means of further reducing complexity, the Markov Chain Monte Carlo (MCMC) algorithm is invoked for the proposed GSTSK detector. Our EXtrinsic Information Transfer (EXIT) chart analysis reveals that the proposed STSK detector is capable of closely approaching the optimal performance, whereas the GSTSK detector advocated exhibits a modest performance gap with respect to the max-log MAP detector.
Mobile handsets, classified as portable devices, are regulated on the amount of user electromagnetic exposure. The widely accepted exposure measurement is the specific absorption rate (SAR). Despite the prevalence of ...
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Mobile handsets, classified as portable devices, are regulated on the amount of user electromagnetic exposure. The widely accepted exposure measurement is the specific absorption rate (SAR). Despite the prevalence of SAR constraints throughout the world, there has been barely any work on the design and analysis of communication signals for SAR-constrained wireless systems. In this paper, we show that multiple-antenna systems greatly reduce the SAR measurements when proper precoders are used. Fifth-generation (5G) and beyond cellular systems will be expected to support high rate uplinks, making multiple transmit antennas on user equipment a necessity. Our proposed SAR-aware transmission for multiple-antenna systems can be applied in 5G handsets to reduce the SAR and increase the rate. Assuming that channel knowledge is available at the transmitter and the receiver, we perform capacity analysis for multiple-antenna systems under both transmit power and SAR constraints. Analytical and numerical results demonstrate substantial performance improvements over schemes that ignore the SAR constraint. Our work shows that SAR-constrained precoders have structures similar to precoders designed for spatially correlated channels.
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