Abstract
In this paper, we present an efficient distributed differential quasi-orthogonal space-time block code (DD-QOSTBC) system for multiple relay networks. First, we propose the DD-QOSTBC transmission which considers two robust STBC-like subsystems in amplify-and-forward multiple relaying over flat fading channel. It is assumed that source has two antennas, and relays and destination have a single antenna. With robust STBC-like subsystem structure, we show that our robust subsystems can be used for an efficient joint suboptimal differential decoding based on a maximum likelihood criterion. Finally, we accomplish the performance evaluation on the proposed DD-QOSTBC system in terms of bit-error-rate.
Highlights
Differential modulation has been regarded as an attractive solution to improve the spectral efficiency with pilot signal elimination at the transmitter
In this paper, we present an efficient distributed differential quasi-orthogonal space-time block code (DD-QOSTBC) system for multiple relay networks
With robust space time block code (STBC)-like subsystem structure, we show that our robust subsystems can be used for an efficient joint suboptimal differential decoding based on a maximum likelihood criterion
Summary
Differential modulation has been regarded as an attractive solution to improve the spectral efficiency with pilot signal elimination at the transmitter. It is difficult to obtain the channel state information (CSI) between transceivers in those channels but differential modulation can be adopted without channel estimations Due to this property, differential modulation is used for timing and frequency synchronization in order to initiate the frame decoding [1]. The advantages of MIMO systems, such as capacity and diversity improvements are compared with singleinput single-output (SISO) system adopting the combination of the differential modulation and an orthogonal space time block code (STBC) [3,4,5]. We propose the efficient joint suboptimal differential decoding (JSDD) utilizing a maximum likelihood (ML) criterion This JSDD rapidly updates both error distances of the detected DD-QOSTBC symbols and additional information to calculate weighting factor.
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