Adaptive M -ary quadrature amplitude spatial modulation

Abstract

Spatial modulation (SM) is a low complexity, highly spectral efficient multiple-input -multiple-output scheme that has been proposed in the literature. The authors apply adaptive modulation to conventional SM in order to maximise the average throughput of the scheme. For this to be possible, the equivalent received signal-to-noise ratio (SNR) needs to be defined and is done so via two proposed approaches: using the first-order statistics SNR and using the average statistics SNR. Average theoretical bit-error-rate (BER) bounds are derived for both of these SNR approaches. Also, adaptive M-ary quadrature amplitude spatial modulation switching levels are determined to maximise the throughput while meeting the average target BER. The Monte Carlo simulation results successfully validate the derived theoretical BER bounds and also prove that the average throughput is improved in comparison to conventional SM. The two proposed definitions for the equivalent received SNR are confirmed to yield comparable BER and throughput performances via simulations, implying that the equivalent received SNR can be defined using either approach.

Instantaneous Bit Error Rate Based ASM Scheme for MPSK Spatial Modulation

“…The LC-ML detector for PSK in [2] is used for detection in this paper. This contributes to a reduction in computational complexity of the proposed system compared with other adaptive SM schemes [7,9,10] that use the ML detection method in [11] for detection.…”

“…In order to achieve this, various closed-loop schemes have been considered. These schemes can be broadly classified into transmit antenna selection [5,6] and adaptive modulation [7,9,10].…”

“…Adaptive modulation can be used to improve either throughput or error performance. In terms of improving throughput the authors in [7] proposed an adaptive QAM SM scheme. Average theoretical BER bounds are derived based on the received SNR.…”

Σχήματα Ιεραρχικής Και Χωρικής Διαμόρφωσης Σε Περιβάλλοντα Γενικευμένων Διαλείψεων

“…Με σκοπό τη μεγιστοποίηση του ρυθμού μετάδοσης υπό σταθερή APEP, στην [112] αξιοποιούνται οι στατιστικές πρώτης τάξης για το SNR σε δίαυλο Rayleigh επιλέγοντας τα αντίστοιχα κατώφλια αλλαγής της τάξης του αστερισμού QAM. Αντίστοιχα, ο πομπός στην [113] προσαρμόζει την τάξη της διαμόρφωσης QAM για διαφορετικά στιγμιότυπα του πίνακα H με σκοπό την ελαχιστοποίηση της ABEP διατηρώντας τη μέση φασματική απόδοση σταθερή.…”