Space-time Block Coded Spatial Modulation Research Articles

Quasi-Orthogonal Space-Time Block Coded Spatial Modulation

The introduction of space-time block code (STBC) can efficiently increase the diversity of original spatial modulation (SM). However, the spectral efficiency of STBC will be reduced gradually with the increase of the transmit antennas. In this contribution, we conceive a novel quasi-orthogonal space-time block coded spatial modulation (QOSTBC-SM) design for multiple-input and multiple-out (MIMO) transmission by reaping their respective benefits, while improving the spectral efficiency compared to conventional space-time block coded spatial modulation (STBC-SM). More specifically, in the proposed QOSTBC-SM structure, the information bits are conveyed via the active antenna index, as well as the QOSTBC blocks at the transmitter, while at the receiver, a low-complexity detection scheme is proposed. Furthermore, a closed-form union bound of the bit error rate (BER) is also quantified by theoretical derivation. Finally, our simulation results demonstrate that QOSTBC-SM is capable of outperforming the conventional counterpart as STBC-SM with higher spectral efficiency.

Optimized Distributed Generalized Reed-Solomon Coding with Space-Time Block Coded Spatial Modulation.

We present a well-known generalized Reed–Solomon (GRS) code incorporated with space-time block coded spatial modulation (STBC-SM) for wireless networks, which is capable of enjoying coded cooperation between the source and the relay. In the proposed distributed GRS-coded STBC-SM (DGRSC-STBC-SM) scheme, the source and relay nodes use distinct GRS codes. At the relay, we employ the concept of information selection to choose the message symbols from the source for further encoding. Thus, the codewords jointly constructed by the source and relay are generated at the destination. For achieving the best codeword set at the destination, we propose an optimal algorithm at the relay to select partial symbols from the source. To reduce the computational complexity, we propose a more practical algorithm with low complexity. Monte Carlo simulation results show that the proposed scheme using the low-complexity algorithm can achieve near-optimal error performance. Furthermore, our proposed scheme provides better error performance than its corresponding coded non-cooperative counterpart and the existing Reed–Solomon coded cooperative SM (RSCC-SM) scheme under identical conditions.

Constant-Envelope Space-Time Shift Keying

From the power amplifier's perspective, the peak-to-average power ratio (PAPR) is of essential importance, especially for both single-RF and reduced-RF multiple-input multiple-output (MIMO) single-carrier schemes. In this context, many of the diversity-oriented index modulation schemes—including the full-RF space-time shift keying (STSK) and the single-RF asynchronous STSK (ASTSK) that invoke randomized signals—exhibit eroded energy-efficiency. To circumvent this problem, we propose a holistic signal construction approach for single-RF, reduced-RF, and full-RF MIMO setups, which always achieve both perfect 0 dB PAPR transmission and inter-channel interference (ICI) free signal detection. More explicitly, first of all , we conceive a new family of single-RF constant-envelope ASTSK (CE-ASTSK), which is capable of substantially outperforming conventional spatial modulation (SM) in both Rayleigh fading and Ricean fading associated with increasing line-of-sight (LoS) power. Second , we propose the new full-RF CE-STSK concept, which is capable of outperforming the orthogonal space-time block codes (STBCs) without either increasing PAPR or imposing ICI. This is particularly beneficial because the conventional linear dispersion code (LDC) approaches always compromise the orthogonality of STBC and hence impose ICI. Third , we also conceive the reduced-RF versions of CE-STSK, which outperform both generalized spatial modulation (GSM) and space-time block coded spatial modulation (STBC-SM). Finally , the proposed schemes are intrinsically amalgamated with turbo detection assisted channel coding, which further confirms the superiority of CE-ASTSK and CE-STSK over SM and STBC in the single-RF and full-RF modes, respectively.

RF mirror media‐based space‐time block coded spatial modulation techniques for two time‐slots

Space-time block coded spatial modulation (STBC-SM) with cyclic structure (STBC-CSM) employs cyclical rotation of activated transmit antenna pairs to transmit Alamouti codewords taken from two different constellation sets to improve the spectral efficiency of STBC-SM. Furthermore, existing literature has shown that media-based modulation (MBM), which employs radio frequency (RF) mirrors demonstrate significant improvement in error performance of wireless systems. Hence, this study proposes the application of MBM to STBC-CSM and STBC-SM in the form of media-based STBC-CSM (MBSTBC-CSM) and MBSTBC-SM, respectively. The theoretical framework of the union-bound on average bit-error probability of M-QAM MBSTBC-CSM and MBSTBC-SM, for the maximum-likelihood (ML) detector is formulated and agrees well with Monte Carlo simulations. Furthermore, due to the large computational complexity of the ML detector, the authors propose a low-complexity near-ML detector for MBSTBC-CSM and MBSTBC-SM, which achieves a near-ML bit error rate performance with reduction in computational complexity.

“Near-Perfect” Finite-Cardinality Generalized Space-Time Shift Keying

Two decades of full-diversity high-rate MIMO research has created perfect Space-Time Block Codes (STBCs), including the Golden code. However, the major stumbling block of their wide-spread employment is their limited energy-efficiency. On one hand, the superposition of their signals results in a high Peak-to-Average Power Ratio (PAPR). On the other hand, the total number of equivalent Inter-Antenna Interference (IAI) contributions that the receiver has to deal with is increased to IAI = M 2 upon using M Transmit Antennas (TAs), which is a substantial extra price compared to the IAI = M of V-BLAST. Against this background, we propose a new family of Finite-Cardinality Generalized Space-Time Shift Keying (FC-GSTSK). More explicitly, the proposed FC-GSTSK is capable of outperforming both V-BLAST and STBC, which is the ultimate objective of full-diversity high-rate MIMO design. Furthermore, following the index modulation philosophy, the proposed FC-GSTSK replaces the signal-additions by the data-carrying signal-selection process. As a benefit, the FC-GSTSK substantially reduces the PAPR of signal transmission. As a further advantage, the equivalent IAI imposed on signal detection is reduced back to the same level as that of the V-BLAST. Moreover, the proposed FC-GSTSK is even capable of consistently outperforming the perfect STBCs in terms of its Peak Signal to Noise-power Ratio (PSNR) that takes into account the power consumption at the transmitter. As a further advance, the reduced-RF-chain based version of FC-GSTSK is also capable of outperforming both Generalized Spatial Modulation (GSM) and Space-Time Block Coded Spatial Modulation (STBC-SM) without increasing the PAPR and the equivalent IAI.

Spatial Permutation Modulation for Multiple-Input Multiple-Output (MIMO) Systems

Spatial modulation (SM) for the multiple-input-multiple-output (MIMO) system has attracted research interests due to its high energy and spectral efficiency. SM creates a new modulation dimension by activating a single transmit antenna according to the data bits. In this paper, we propose spatial permutation modulation (SPM) that modulates data bits to a permutation vector and activates the transmit antenna at successive time instants accordingly. The SPM achieves higher diversity and thus lower error rate since the permutation vector disperses data along the time coordinate. The theoretical model of diversity and error rate are derived in both the slow-fading channel and fast-fading channel, leading to systematic and the fast SPM design exploration. Additionally, to show that the SPM can be easily combined with other SM-based techniques, space-time block coded spatial permutation modulation (STBC-SPM) and quadrature spatial permutation modulation (QSPM) is exemplarily designed based on space-time block coded spatial modulation (STBC-SM) and quadrature spatial modulation (QSM), respectively. The numerical results demonstrate the accuracy of our theoretical analyses and the superior SPM/STBC-SPM/QSPM performances to SM/STBC-SM/QSM, respectively, especially under the severe environments like low receive diversity or spatially-correlated channel, where SM fails to provide satisfactory performance. Under the environments where systems are allowed to operate with high throughputs, SPM also achieves lower error rate performance than SM. Last but not least, inspired by SM, numerous index modulation (IM) have been invented by activating various transmission entities, e.g., subcarrier in the orthogonal frequency division multiplexing (OFDM) system. The generalization from the SM to SPM can be easily applied to another IM system for the design of index permutation modulation (IPM).

Improved Super-Orthogonal Trellis-Coded Spatial Modulation Using STBC-CSM

Trellis coded modulation (TCM) is a scheme that enhances the error performance without extra power not bandwidth. This paper presents a modified Super-Orthogonal Trellis-Coded Spatial Modulation (SOTC-SM) based on a cyclic structure of the Space Time Coding. The developed code benefits from expanded codebook of the Space Time Block Coded Spatial Modulation (STBC-SM) to enhance the coding gain. The set-partitioning and the code design based on the expanded codebook was given for codes with rate of 2 and 3 bps and can be easily extended to higher rates. The Bit-Error Rate (BER) performance of the proposed scheme was evaluated via computer simulation. It was shown that the proposed scheme outperforms the SOTC-SM performance for the same number of transmit antennas.

Modified codewords design for space–time block coded spatial modulation

Two kinds of modified codewords for space–time block coded spatial modulation (STBC-SM) are presented in this study. The first modified codeword introduces a concept of flexible coefficients into the M-ary phase shift keying STBC-SM. A method is proposed to obtain the optimal flexible coefficients. Moreover, the first modified codewords can also be applied to the systems developed from the STBC-SM. In the second provided codewords, super-orthogonal space–time trellis codes are applied in STBC-SM. Therefore, a higher spectral efficiency is obtained compared with the original STBC-SM. Finally, the simulation results and theoretical analysis demonstrate these performance advantages of the two kinds of modified codewords for STBC-SM.

UHDTV 방송을 위한 공간 변조 다중 안테나 시스템 수신 성능 분석

In this paper, the reception performance of spatial modulation multiple-output multiple-input (MIMO) is analyzed for high speed terrestrial broadcasting. The MIMO scheme is required to reduce the inter symbol interference (ISI) and spatial correlation. The spatial modulation scheme solves the problem of ISI, but the spatial correlation degrades the reception performance of SM scheme. The space-time block coded spatial modulation (STBC-SM) is combined the SM system with space-time block code (STBC) for reducing the effects of the spatial correlation. However, the STBC-SM scheme degrades the spectral efficiency by transmitting same data in the two symbol period. The double space-time transmit diversity with spatial modulation (DSTTD-SM) scheme transmits the data with full antenna combination. To adapt these SM MIMO systems into the terrestrial broadcasting system, the reception performance is analyzed using computer simulation in SUI channel environments.

Soft‐output space‐time block coded spatial modulation

Space-time block coded spatial modulation (STBC-SM) is a recently proposed multiple-input–multiple-output transmission scheme, which combines spatial modulation (SM) and Alamouti's space-time block code (STBC) in such a manner so as to retain the primary advantages of SM and STBC, while avoiding their drawbacks, resulting in an improved system error performance. In this study, the authors propose a soft-output maximum-likelihood (ML) detector (SOMLD) and a soft-output low-complexity near-ML detector (SOLCD) for STBC-SM transmission. Monte-Carlo simulations demonstrate that the error performance of the proposed schemes are able to closely match that of the hard decision ML detector for uncoded channel conditions, while significant improvement in error performance is demonstrated for coded systems. Furthermore, compared with SOMLD, SOLCD imposes a significantly lower computational complexity, while achieving near-ML error performance.

Super-orthogonal trellis-coded spatial modulation

Spatial modulation (SM), which employs the indices of multiple transmit antennas to transmit information in addition to the conventional M-ary signal constellations, is a novel transmission technique that has been proposed for multiple-input multiple-output systems. In this study, a new class of space-time trellis codes, called ‘super-orthogonal trellis-coded SM’ (SOTC-SM), is proposed. These codes combine set partitioning and a super set of space-time block coded SM (STBC-SM) codewords to achieve maximal diversity and coding gains by exploiting both SM and space-time block codes. Unlike super-orthogonal space-time trellis codes (SOSTTCs), which parametrise the orthogonal STBCs, these new codes expand the antenna constellation using the principle of SM. Systematic construction methods are presented for the SOTC-SM scheme and design examples are given for 2, 4 and 8 trellis states, at 2, 3 and 4 bits/s/Hz spectral efficiencies. The approximate bit-error probability performance of SOTC-SM is derived and shown to match computer simulation results. A simplified maximum likelihood detection method for the proposed scheme is given. It is shown through computer simulations that the proposed SOTC-SM schemes achieve significantly better error performance than SOSTTCs with comparable complexity.

Space-Time Block Coded Spatial Modulation

A novel multiple-input multiple-output (MIMO) transmission scheme, called space-time block coded spatial modulation (STBC-SM), is proposed. It combines spatial modulation (SM) and space-time block coding (STBC) to take advantage of the benefits of both while avoiding their drawbacks. In the STBC-SM scheme, the transmitted information symbols are expanded not only to the space and time domains but also to the spatial (antenna) domain which corresponds to the on/off status of the transmit antennas available at the space domain, and therefore both core STBC and antenna indices carry information. A general technique is presented for the design of the STBC-SM scheme for any number of transmit antennas. Besides the high spectral efficiency advantage provided by the antenna domain, the proposed scheme is also optimized by deriving its diversity and coding gains to exploit the diversity advantage of STBC. A low-complexity maximum likelihood (ML) decoder is given for the new scheme which profits from the orthogonality of the core STBC. The performance advantages of the STBC-SM over simple SM and over V-BLAST are shown by simulation results for various spectral efficiencies and are supported by the derivation of a closed form expression for the union bound on the bit error probability.