Performance Of Space-time Block Codes Research Articles

Performance comparison of space-time block and trellis codes in the MIMO land mobile satellite channels

Due to the crowded orbits and shortage of frequency resources, the use of MIMO technology to improve spectrum efficiency and an increase of the capacity have become a necessary trend of broadband satellite communication. Firstly, we analyze the main influenced factors and compare the bit error rate (BER) performance of space-time block code (STBC) scheme and space-time trellis code (STTC) scheme. Then we build up the model of land mobile satellite (LMS) channel under different environments by using 3-state Markov chain. This paper emphatically studies the BER performance of STTC and STBC in the MIMO satellite channel. The main emphasis is placed on the effects of different factors, such as terminal environment and elevation angles, on the BER performance of STBC and STTC schemes. Simulation results indicate that performance of STTC in Rayleigh channel is obviously improved with the increasing number of transmitting and receiving antennas, but the encoder state has little impact on the performance. In the Rayleigh channel, the performance of Alamouti code is better than that of STTC. In the LMS channel, performance of these two kinds of space-time coding in open area is optimal, and in the urban area it is the worst. Nevertheless, performance of STTC is slightly superior to the performance of STBC under different circumstances. Under the same environmental conditions, BER of STBC and STTC reduces with the increase of the satellite altitude angle, and therefore, the BER curves of STTC fall faster.

Space-time block coding for undersea acoustic links

Current research in undersea communication scenario focuses on the applications of undersea acoustic networks in environmental data collection, pollution monitoring, offshore surveillance, coastal surveillance, etc. The various constraints encountered in undersea acoustic communications are mainly low bandwidth, high latency, high failure rates of acoustic links, and multipath propagation effects. Multipath effects in undersea environments are due to the reflection of sound by the sea surface and sea bottom as well as refraction of sound in water. As a result, the receiver gets a bewildering mix of signals. The receiving subsystems of the undersea networks perform special signal processing techniques for regenerating the data streams from the multipath composite signals in a MIMO configurable network. The performance of Space-Time Block Coding (STBC) diversity technique has been adopted in this paper for improving the reliability of the undersea network. In the simplest form of MIMO configuration, two transmitting transducers send out the data stream and its modified versions in two time slots on independently fading environments, leading to substantial improvements in the error rate performance. For a shallow water medium range channel, which exhibits the Rayleigh fading characteristics, the error rate performance has been found to be 7 x 10-6 for 16-QAM based STBC.

English

In this paper, an analysis for the bit error rate (BER) performance of space-time block codes (STBC) from generalized orthogonal designs for QAM modulation has been presented. Space-time block codes (STBC) offer high diversity gain and among which orthogonal STBCs are very attractive due to its relatively simpler design and low decoding complexity. Performance of Alamouti STBC and Orthogonal STBC with rate ½ for different transmitting and receiving antennas under Rayleigh fading situation has been analyzed. The decoding techniques used for this analysis are ZF, MMSE and ML. In all the cases, the bit error rate has been treated as the figure of merit and its change with SNR are observed due to different parameter variations of the channel distribution as well as different antenna configurations.

Effect of Generalized-K Fading on the Performance of Symmetric Coordinate Interleaved Orthogonal Designs

In this letter, an efficient method of evaluating the performance of space-time block codes (STBCs) from symmetrically structured coordinate interleaved orthogonal designs (CIODs) is presented over generalized-K MIMO fading channels. By effectively approximating the moment generating function (MGF), we derive approximate closed-form expressions for the symbol pairwise error rate (SPER) and corresponding tight approximate symbol error rate (SER) of STBCs from symmetric CIODs. Finally, various Monte-Carlo simulations are performed to validate our theoretical results.

Channel capacity and space-time block coding for coherent optical MIMO multi-mode fiber links

The capacity enhancement for random coherent optical multiple-input multiple-output (MIMO) channels in multi-mode fiber (MMF) links is investigated theoretically. Additionally, the performance of space-time block coding (STBC) techniques for achieving high reliability optical MIMO transmission is numerically examined. A comparative study is performed by considering several schemes that employ multiple transmitters/receivers. Simulation results of these schemes, in terms of bit error rate (BER) as a function of optical signal to noise ratio (OSNR), are provided.

Space-time block code based MIMO encoding for large core step index plastic optical fiber transmission systems

The performance of Space-Time Block Codes combined with Discrete MultiTone modulation applied in a Large Core Step-Index POF link is examined theoretically. A comparative study is performed considering several schemes that employ multiple transmitters/receivers and a fiber span of 100 m. The performance enhancement of the higher diversity order configurations is revealed by application of a Margin Adaptive Bit Loading technique that employs Chow's algorithm. Simulations results of the above schemes, in terms of Bit Error Rate as a function of the received Signal to Noise Ratio, are provided. An improvement of more than 6 dB for the required electrical SNR is observed for a 3 × 1 configuration, in order to achieve a 10(-3) BER value, as compared to a conventional Single Input Single output scheme.

Effect of joint spatial correlation on the diversity performance of space-time block codes

We characterize the effect of joint spatial correlation on the diversity performance of multiple-input multiple-output (MIMO) systems. The joint spatial correlation is structured by the coupling matrix whose elements determine the average power coupling between the transmit and receive eigenmodes. We first derive the closed-form expression for the exact symbol error probability (SEP) of orthogonal space-time block codes over jointly correlated MIMO Rayleigh-fading channels. We then show that the achievable diversity order is equal to the number of nonzero elements of the power coupling matrix and establish the Schur monotonicity theorems on the SEP and the effective fading figure as a functional of elements of the power coupling matrix.

Outage analysis of interference-limited systems using STBC with co-channel MIMO interferers

The performance of Space-Time Block Coding (STBC) with co-channel MIMO interference is investigated. For an interference-limited environment, the closed-formexpressions for the probability density functions of the signalto-interference ratio are derived and applied to analyze the outage probability with three typical types of co-channel MIMO interferers: STBC, open-loop spatial multiplexing and closed-loop spatial multiplexing. Both theoretical analyses and simulation results show that the performance of STBC is independent of the MIMO modes used in the interfering links.

The performance of space-time block codes from coordinate interleaved orthogonal designs over nakagami-m fading channels

Space-time block codes (STBCs) from coordinate interleaved orthogonal designs (CIODs) offer several advantages including full-diversity and single-symbol decodability. In an effort to assess their performance in quasi-static frequency nonselective i.i.d. Nakagami-m fading channels, we analyze the error rate, outage capacity, and information outage probability. First, based on an accurate closed-form formula for the average symbol pairwise error rate (SPER), we derive tight union upper and lower bounds on the symbol-error rate (SER). Second, we apply Gaussian and Gamma approximations to provide closed form expressions for the outage capacity. Third, using high signal-to-noise ratio (SNR) and moment-matching approximation techniques, we also derive accurate closed-form approximations for the information outage probability (IOP). Finally, we show that STBCs from CIODs provide full-diversity by deriving SER based and IOP-based asymptotic and instantaneous diversity orders. Monte-Carlo simulations show that the analytical results agree with simulation experiments.

Performance analysis of orthogonal space-time block codes over time-selective channels, and applications to code design of Gi systems

Many existing works on space-time block codes (STBC) assume the channels are block-wise constant, but this assumption does not always hold. In the more general case of time-selective channels, the channel matrix is no longer orthogonal, so inter-symbol interference (ESI) is generated and the performance is greatly reduced. Several decoders have been proposed to eliminate the ESI, but it remains unclear how and to what extent the performance is affected by the ISI. In this paper, we introduce an approach to analyze the performance of STBC over time-selective channels, with arbitrary numbers of antennas for which orthogonal STBC's are defined. Exact error performances are obtained in closed form. Furthermore, the analysis reveals the relationship between the ISI and the structure of STBC matrices. Considering G i systems, we then propose one proposition and two design criteria, following which it is easy to design or search for better STBC's that have less ISI compared with the original code matrix.

Macro-Diversity Scheme for a Point-to-Multipoint Communication System by means of D-STBC Method in Fast Fading Environment

In recent years, the space-time block coding (STBC) method has attracted attention to provide transmission diversity in mobile communication systems. Although the STBC method is very effective in slow fading environments, its performance in fast fading environments has yet to be clearly verified. In this paper we propose a railway radio communication system using space-time coding in cooperation with two base stations. Here, we considered the differential STBC (D-STBC) method in railway communication system to overcome difficulties caused by the fast fading environment. We have compared the performance of STBC and D-STBC method where there is frequency offset between two base stations. Moreover, we have presented the simulation result of overall performance of the system including frequency offset and transmission time delay when operating D-STBC method. The overall evaluation on this paper shows that the D-STBC method is suitable for realizing highly reliable railway communication systems.

Performance Analysis of Space-Time Block Codes in Flat Fading MIMO Channels with Offsets

We consider the effect of imperfect carrier offset compensation on the performance of space-time block codes. The symbol error rate (SER) for orthogonal space-time block code (OSTBC) is derived here by taking into account the carrier offset and the resulting imperfect channel state information (CSI) in Rayleigh flat fading MIMO wireless channels with offsets.

Performance of Space-Time Block Coding in Powerline and Satellite Communications

In this paper Space-Time Block Coding (STBC) is examined in powerline and satellite communications, comparing the gains that this coding-modulation technique provides to these communications systems. The powerline environment is assumed to be a frequency-selective, multipath fading environment with Additive White Class A Noise (AWCN), which is used to model the actual powerline noise characteristics. The satellite channel for urban area, modeled as a combination of Rayleigh and log-normal processes with the presence of Additive White Gaussian Noise (AWGN) is also studied. System efficiency is enhanced by the application of Orthogonal Frequency Division Multiplexing (OFDM), convolutional coding and block interleaving and the performance of different Phase Shift Keying (PSK) modulation schemes under the imposed channel conditions is investigated. The performance of the system is assessed by the commonly used Bit Error Rate (BER) vs. Signal to Noise Ratio (SNR) diagrams and there is also a comparison regarding the throughput efficiency among the examined systems. As stated in the results section, STBC can be used in powerline and satellite communications providing remarkable results, comparable to those in terrestrial wireless communications where STBC is nowadays a rather mature technique

On decoding algorithm and performance of space-time block codes

In this letter, we present a unified mathematical expression for the decoding algorithm of space-time block codes (STBC). Based on the unified expression, we make a comparison of the STBC transmit diversity and the maximal-ratio combining MRC receive diversity, and analyze the symbol error probability for the STBC transmissions. The effects of the channel correlation and the number of transmit and receive antennas on the performance of the STBC are discussed.

Space-time block coding for wireless communications: performance results

We document the performance of space-time block codes, which provide a new paradigm for transmission over Rayleigh fading channels using multiple transmit antennas. Data is encoded using a space-time block code, and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. Maximum likelihood decoding is achieved in a simple way through decoupling of the signals transmitted from different antennas rather than joint detection. This uses the orthogonal structure of the space-time block code and gives a maximum likelihood decoding algorithm which is based only on linear processing at the receiver. We review the encoding and decoding algorithms for various codes and provide simulation results demonstrating their performance. It is shown that using multiple transmit antennas and space-time block coding provides remarkable performance at the expense of almost no extra processing.