New Signal Design for Enhanced Spatial Modulation with Multiple Constellations

International audienceIn this paper, we introduce a new signal design for the Enhanced Spatial Modulation (ESM) concept, which was recently proposed by the present authors. The basic idea of ESM is to convey information bits not only by the indexes of the active transmit antennas, but also by the types of the multiple constellations used. Design of the original ESM schemes involved one or more secondary modulations, which were derived using a single step of geometric interpolation in the signal constellation plane. In the new design, we go one step further in the interpolation process and derive additional modulations leading to a significant increase of the number of active antenna and modulation combinations used. A design example is given for 10 bits per channel use (bpcu) transmission using four transmit antennas two of which are active at a time. The new design is compared to conventional multi-stream spatial modulation (MSM) and to our previously proposed ESM scheme. The analysis and the simulation results confirm a signal-to-noise ratio (SNR) gain of 2.2 dB over MSM and 0.4 dB over ESM when the three schemes are operated at the same spectral efficiency

Enhanced Spatial Modulation with Multiple Constellations and Two Active Antennas

International audienceIn this paper, we focus on spatial modulation (SM) which uses two active transmit (TX) antennas, and we introduce an Enhanced Spatial Modulation (ESM) technique, which conveys information bits not only by the indexes of the active antennas, but also by the constellations transmitted from each of them. The main feature of the proposed technique is that in addition to a primary modulation, it uses a secondary modulation that is obtained through geometric interpolation in the signal space. The secondary modulation has a reduced transmit energy compared to the primary modulation, and this leads to significant performance gains for the same spectral efficiency. We also describe other variants of the proposed ESM scheme in which the primary modulation is partitioned into two or more subsets and the lower-energy subsets are used in a larger number of combinations. We give design examples using four transmit antennas and 16QAM and 64QAM as primary modulations. The proposed techniques are compared to Conventional SM (CSM) and the results indicate that they provide a significant performance gain over CSM in terms of the symbol vector error rate (SVER) performance

Linear Interference Suppression with Covariance Mismatches in MIMO-OFDM Downlink

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SINR Enhancement of Interference Rejection Combining for the MIMO Interference Channel

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Robust MIMO Detection Under Imperfect CSI Based on Bayesian Model Selection

International audienceA robust receiver for multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems is proposed. We are interested in the scenario when only a limited number of observations in both time and frequency domains are available. For this scenario, perfect channel state information is impossible to obtain and the receiver suffers from statistical information mismatch. To overcome this limitation, we first propose the optimum receiver by performing jointly channel and data estimation. For statistical information mismatch, we construct a finite set of covariance matrices and derive a model-selection scheme based on Bayesian Model Selection. Finally, the sliding-window scheme is used in order to enhance the model selection accuracy. Simulation results are presented, showing that the proposed scheme outperforms the conventional scheme under imperfect channel knowledge

Moving-Average Based Interference Suppression on Frequency Selective SIMO Channels

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