Performance Of Orthogonal Space-time Block Research Articles

Performance analysis of orthogonal space‐time block codes over Nakagami‐qMIMO RFID backscattering channels

The authors employ the conditional moment generating function approach to analyse the performance of orthogonal space-time block codes over Nakagami- q (Hoyt) multiple-input multiple-output radio frequency identification backscattering channels. New exact and asymptotic symbol error rate expressions are derived for the case of two and four receiving antennas N = 2 , 4 . The exact expressions are in the form of a sum of infinite series while the asymptotic ones are in the closed form. The diversity order that the system can achieve is found to be L , where L is the number of tag antennas, and the performance of this system is found to be more sensitive to the channel condition (the q parameter) of the forward link than that of the backscattering link. The theoretical results (exact and asymptotic) are verified through comparison with simulation results.

Robust Precoded OSTBC for GFDM Systems

Generalized Frequency Division Multiplexing (GFDM) has been proposed recently as a candidate for the next generation wireless communications systems (5G) due to its attractive properties that seem to cover the envisioned applications. In order to make GFDM more robust to multipath fading effects the techniques of space-time block codes (STBC) can be added to its implementation. In this article, we consider the performance of orthogonal space-time block coded (OSTBC) GFDM systems over Rayleigh fading channel. In addition, to further enhance performance, Discrete Prolate Spheroidal Sequences (DPSSs or multi-tapers) can be exploited to turn conventional GFDM to an improved orthogonal system. In this work we investigated a precoded OSTBC Multitaper GFDM system along with conventional GFDM. The symbol error rate (SER) performance for precoded OSTBC-(M)GFDM systems over a Rayleigh fading channel is examined and a good match between simulation results and analytical expressions is seen to exist.

Performance Analysis of Orthogonal STBC in Generalized- $K$ Fading MIMO Channels

This paper investigates the performance of orthogonal space-time block codes over generalized-K fading multiple-input-multiple-output (MIMO) channels. We present exact analytical expressions for three important performance measures, namely, outage probability, average capacity, and average symbol error rate (SER). In addition, we derive simple expressions for key parameters dictating the system performance at the high and low signal-to-noise ratio (SNR) regimes, i.e., diversity order, coding gain, minimum energy per information bit, and wideband slope, which provide insight on how various key system parameters, such as number of antennas and fading severity level, affect the performance of the system.

Cascaded generalised-K fading channel

A versatile fading distribution that generalises many commonly used models for multi-path and shadow fading is the so-called generalised-K (KG) distribution. By considering the product of N independent but not necessarily identically distributed (n.i.d.) squared KG random variables (RVs), we derive exact closed-form expressions for the moment generating function, probability density function, cumulative distribution function and the moments of the cascaded KG fading channel. Expressions for the ergodic capacity and the error performance of different digital modulation schemes are also obtained. Based on the above mentioned formulas, we analyse the performance of orthogonal space-time block codes over multiple-input multiple-output keyhole KG fading channels. Various performance evaluation results demonstrate the proposed mathematical analysis.

Optimal Superimposed Training Design for Spatially Correlated Fading MIMO Channels

The problem of channel estimation for spatially correlated fading multiple-input multiple-output (MIMO) systems is considered. Based on the channel's second order statistic, the minimum mean-square error (MMSE) channel estimator that works with the superimposed training signal is first developed. The problem of designing the optimal superimposed signal is then addressed and solved with an iterative optimization algorithm. Results show that under the constraint of equal training power and bandwidth efficiency, our optimal design of the superimposed training signal leads to a significant reduction in channel estimation error when compared to the conventional design of time-multiplexing training, especially for slowly time-varying channels with a large coherence time. The issue of power allocation between the information-bearing and training signals for detection enhancement is also investigated. Simulation results demonstrate excellent bit-error-rate performance of orthogonal space-time block codes with our proposed channel estimation.

On the Error Probability of Orthogonal Space-Time Block Codes Over Keyhole MIMO Channels

It has been shown recently that multiple-input multiple-output (MIMO) fading channels could experience a keyhole phenomenon, under which the performance of MIMO systems will be degraded in terms of link quality as well as capacity. In this paper, the performance of orthogonal space-time block codes in MIMO fading channels under keyhole condition is analyzed. Closed-form expressions for the error probability of space-time block codes as well as diversity gains of keyhole channels are derived. We prove that the maximum spatial diversity gain of a keyhole channel with to transmit and n receive antennas is min(m, n) when m ne n. In the case of m = n, the achievable diversity gain is less than n but higher than n - 1. Accordingly, for space-time block codes in keyhole channels, there are two forms of error rate expressions for m ne n and m = n, respectively. Furthermore, coding gains of various space-time block codes in keyhole channels are obtained. Simulation results are also provided to demonstrate the accuracy of our analytical results.

On the performance of orthogonal space-time block coding with quantized feedback

Orthogonal space-time block coding (OSTBC) is a recent technique that provides maximal diversity gains on a space-time channel at a very modest computational cost. Recently, several authors have suggested to improve the performance of an OSTBC system by using a feedback of channel state information from the receiver to the transmitter. In this letter, we study the performance of an OSTBC system with quantized low-rate feedback. We establish conditions under which the system achieves full diversity and we also analyze the performance of a method that employs a feedback consisting of only one information bit.