Extended orthogonal space-time block coding scheme in asynchronous two-way cooperative relay networks over frequency-selective fading channels

Abstract

In this paper, we propose a new robust closed-loop extended orthogonal space-time block coding (EO-STBC) scheme for two-way four relay networks over frequency selective fading channels with imperfect synchronization. It is a three time slot scheme where the first one is specified for the two terminals while the other two are specified for amplify-and-forward (AF) relays. An orthogonal frequency division multiplexing (OFDM) data structure is employed at the two terminals using cyclic prefix (CP) insertion to combat the effect of multipaths and time asynchronicity. Full spatial diversity with array gain and code rate of 2 over 3 is achieved through applying a simple feedback approach over only two relays. Simulation results are used to show the performance improvements resulting from the proposed system. Furthermore, our scheme uses a simple symbol-wise maximum likelihood (ML) decoder to extract the information data. © 2011 IEEE

Distributed space-time block coding for two-way wireless relaying networks: Improved performance under imperfect synchronization

“…The literature has few approaches to mitigate this issue for TWRNs, where most of these methods deal with the imperfect synchronization by using Analog Network Coding (ANC), some of them based on the use of Orthogonal Frequency Division Modulation (OFDM) with Cyclic Prefix (CP) and the other are based on convolutional coding, leading to extracomputational complexity at relaying nodes and the receiving terminals [14]- [16]. In [6], [7], a simple PIC based detector is proposed to mitigate the performance degradation in two and four relaying nodes TWRN, respectively.…”

“…However, most of the existing research on D-STBC, whether in one or two-way networks, assume perfect synchronization among the relaying nodes, so that all the received symbols have the same timing and propagation delay [4]- [7]. Unfortunately, this assumption is unrealistic or at the very least it imposes conditions that will be difficult or even impossible to achieve in a real world networks [8].…”

A Study on Orthogonal Space-time Block Codes for Cooperative Function

“…Mannai et al [7] studied a new robust closed-loop extended orthogonal space-time block coding (EO-STBC) scheme for twoway four relay networks over frequency selective fading channels with imperfect synchronization. It is a three time slot scheme where the first one is specified for the two terminals while the other two are specified for amplify-and-forward (AF) relays.…”

“…The capacity (2.1) is a random variable and does not give a single-number representation of channel quality. Two straightforward summaries are commonly used: the mean (or ergodic) capacity [9][10][11] and capacity outage [3,7,9,12]. Capacity outage measures (usually based on simulation) are often denoted C0:1 or C0:01, i.e., Now they can focus on the information theoretic capacity of a MIMO system.…”

“…Multipath fading has been habitually obscurity in wireless transmission. However, MIMO successfully takes advantage of random fading [2][3][4][5][6] and when available, multipath delay spread [7,8] for improving the quality of wireless communication. That improved performance requires no extra spectrum, but demands added hardware and complexity (Figure 3).…”