Improved Spatial Modulation for High Spectral Efficiency

Spatial Modulation (SM) is a technique that can enhance the capacity of MIMO schemes by exploiting the index of transmit antenna to convey information bits. In this paper, we describe this technique, and present a new MIMO transmission scheme that combines SM and spatial multiplexing. In the basic form of SM, only one out of MT available antennas is selected for transmission in any given symbol interval. We propose to use more than one antenna to transmit several symbols simultaneously. This would increase the spectral efficiency. At the receiver, an optimal detector is employed to jointly estimate the transmitted symbols as well as the index of the active transmit antennas. In this paper we evaluate the performance of this scheme in an uncorrelated Rayleigh fading channel. The simulations results show that the proposed scheme outperforms the optimal SM and V-BLAST (Vertical Bell Laboratories Layered space-time at high signal-to-noise ratio (SNR). For example, if we seek a spectral efficiency of 8 bits/s/Hz at bit error rate (BER) of 10^-5, the proposed scheme provides 5dB and 7dB improvements over SM and V-BLAST, respectively.Comment: 7 pages, 4 figures, 1 table, International Journal of Distributed and Parallel Systems (IJDPS) Vol.3, No.2, March 201

Realistic performance measurement for body-centric spatial modulation links

Spatial Modulation is a new transmission mode which increases spectral efficiency by employing information-driven transmit antenna selection. This performance is realized at a reduced hardware complexity and cost because only a single radio-frequency transmit chain is necessary. A measurement campaign is performed to assess the characteristics of spatial modulation over a body-centric communication channel, transmitting from a walking person with textile antennas integrated into the front and back sections of a garment, towards a base-station in realistic conditions. In the transmitted frames, additional spatial multiplexing as well as space-time coded data blocks are included. The off-body communication link is analyzed for line-of-sight as well as non line-of-sight radio wave propagation, comparing the characteristics of the different transmission modes under equal propagation conditions and for an equal channel capacity of 2 bit/s/Hz

Investigation of VBLAST Equalization Technique for Underwater Acoustic Communications

Underwater Acoustic Communications (UWAC) is an emerging technology in the field of underwater communications, and it is challenging because of the signal attenuation of the sound waves. Multiple Input and Multiple-Output (MIMO) is introduced in UWAC because of its support in enhancing the data throughput even under the conditions of interference, signal fading, and multipath. The paper presents the concept and analysis of 2× 2 MIMO UWAC systems that uses a 4- QAM spatial modulation scheme thus minimizing the decoding complexity and overcoming the Inter Channel Interference (IChI). Bit Error Rate (BER) investigation is carried out over different link distances under acoustic Line of Sight (LOS). The utilization of Zero Forcing (ZF) and Vertical-Bell Laboratories Layered Space-Time (VBLAST) equalizers, which estimates the transmitted data proves a success of removing Inter Symbol Interference (ISI).  The ISI caused due to multipath effect and scattering in UWAC can be reduced by iterative process considered in VBLAST.  A study is made on how the distance between the transmitter and the receiver and the Doppler Effect has its impact on the performance of the system

Investigation of VBLAST Equalization Technique for Underwater Acoustic Communications

Underwater Acoustic Communications (UWAC) is an emerging technology in the field of underwater communications, and it is challenging because of the signal attenuation of the sound waves. Multiple Input and Multiple-Output (MIMO) is introduced in UWAC because of its support in enhancing the data throughput even under the conditions of interference, signal fading, and multipath. The paper presents the concept and analysis of 2× 2 MIMO UWAC systems that uses a 4- QAM spatial modulation scheme thus minimizing the decoding complexity and overcoming the Inter Channel Interference (IChI). Bit Error Rate (BER) investigation is carried out over different link distances under acoustic Line of Sight (LOS). The utilization of Zero Forcing (ZF) and Vertical-Bell Laboratories Layered Space-Time (VBLAST) equalizers, which estimates the transmitted data proves a success of removing Inter Symbol Interference (ISI).  The ISI caused due to multipath effect and scattering in UWAC can be reduced by iterative process considered in VBLAST.  A study is made on how the distance between the transmitter and the receiver and the Doppler Effect has its impact on the performance of the system

Performance Analysis and Optimal Detection of Spatial Modulation

In this paper, we propose the optimal detector for spatial modulation. The new detector performs significant better than the original (~4 dB gain), and we derive the closed form expression for the average bit error probability. The optimal detector of SM shows performance gain (~1.5 ?3 dB) over popular multiple antenna system, making it an excellent prospect for future wireless communication

An Analytical Design: Performance Comparison of MMSE and ZF Detector

By using multiple antennas at transmitter and receiver sides, the performance of the system can be enhanced in terms of high data rates by applying the concept of multiplexing and diversity as compared to single antenna systems. In this article we will study and compare the performance of BLAST architecture with different detectors like Zero Forcing (ZF), Minimum Mean Square Error (MMSE). Furthermore, we introduced OSIC schemes to improve the independent coded BLAST system and to combat the error propagation. We have also analyzed the BER performance of these MIMO schemes in Rayleigh and Rician fading channel. Finally we observed that the performance of BPSK and QPSK modulation techniques is almost same in BLAST architecture, while using the given detection techniques in both the channels and 16-QAM modulation technique gives the worst result. Keywords: Binary Phase Shift Key (BPSK), Bit Error Rate (BER), Multiple input multiple output (MIMO),Maximum Likelihood (ML), Minimum mean square error (MMSE), Zero Forcing (ZF), Ordered Successive Interference Cancellation (OSIC), Quardrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), Independent identically distributed (i.i.d), Bell Laboratories Layered Space-Time (BLAST)  

On the Performance of Space Shift Keying for Optical Wireless Communications

International audienceIn this paper, we study the performance of Space Shift Keying (SSK) modulation applied to optical wireless channels. The optical Multiple-Input-Single-Output (MISO) channel used here is obtained through measurements. The experimental setup consists of two lasers and an optical receiver. Using the channel measurements, the performance of SSK is compared to the Single-Input-Single-Output (SISO) transmission case. We build upon a recent finding, obtained for a two-transmitter case, that power imbalance at the transmitters can enhance the performance of SSK, especially in highly correlated channels. It is found in this paper that SSK applied to real optical wireless channels outperforms SISO and Single-Input-Multiple-Output (SIMO) transmission if more than four optical transmitters are used. Furthermore, we show that Space Shift Keying can also exceed Multiple-Input-Multiple-Output (MIMO) setups which apply repetition coding as SSK exploits receive-diversity in a better way

Generalized space-time shift keying designed for flexible diversity-, multiplexing- and complexity-tradeoffs

In this paper, motivated by the recent concept of Spatial Modulation (SM), we propose a novel Generalized Space-Time Shift Keying (G-STSK) architecture, which acts as a unified Multiple-Input Multiple-Output (MIMO) framework. More specifically, our G-STSK scheme is based on the rationale that P out of Q dispersion matrices are selected and linearly combined in conjunction with the classic PSK/QAM modulation, where activating P out of Q dispersion matrices provides an implicit means of conveying information bits in addition to the classic modem. Due to its substantial flexibility, our G-STSK framework includes diverse MIMO arrangements, such as SM, Space-Shift Keying (SSK), Linear Dispersion Codes (LDCs), Space-Time Block Codes (STBCs) and Bell Lab’s Layered Space-Time (BLAST) scheme. Hence it has the potential of subsuming all of them, when flexibly adapting a set of system parameters. Moreover, we also derive the Discrete-input Continuous-output Memoryless Channel (DCMC) capacity for our G-STSK scheme, which serves as the unified capacity limit, hence quantifying the capacity of the class of MIMO arrangements. Furthermore, EXtrinsic Information Transfer (EXIT) chart analysis is used for designing our G-STSK scheme and for characterizing its iterative decoding convergence