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In this paper, we consider asynchronous two-way wireless relay networks with amplify-and-forward protocol (AF- TWRN), where the distributed space-time code (DSTC) is utilized without synchronization among relays to assist the communication between two terminals. We analyze the pairwise error probability (PEP) behavior of DSTC for AF-TWRN under frequency-selective channels. From our analysis, it is...
In the space-time cooperative relay orthogonal frequency division multiplexing (OFDM) system, a challenge is the lack of perfect timing synchronization, which degrades the performance of the receiver greatly. This paper investigates a timing synchronization scheme to solve this problem. Unlike the conventional algorithms, our attempt primarily aims to obtain the different time delays of source and...
In most cooperative communications works, perfect synchronization among relay nodes is assumed in order to achieve cooperative diversity. However, this assumption is not realistic due to the distributed nature of each relay node. In this paper, we propose a family of distributed space-time trellis code (DSTTC) that does not require the synchronization assumption. It is shown that the proposed DSTTC...
In this paper, we study the asynchronous cooperative diversity schemes employing the amplify-and-forward (AF) protocols over the frequency-selective channel. We consider three time-division-multiple-access (TDMA) based cooperation protocols and derive the corresponding pairwise error probabilities (PEP). From our analysis, it is seen that of the paths from the source to relays and from relays to the...
In order to achieve predictability, time-triggered communication systems have been proposed for use in in-vehicle applications, in particular for safety-critical applications. Timing properties play a crucial role in a time-triggered system as activities in such a system are all triggered by the passage of time. In this paper, we propose techniques for specifying and verifying the timing properties...
In current cooperative communication schemes, to achieve cooperative diversity, synchronization between terminals is usually assumed, which may not be practical. In this paper, shift-orthogonal space-time block codes (SOSTBC) for relay networks without the assumption of synchronization is described. Then based on the set of zero correlation zone (ZCZ) sequence, the definitions of zero cross-correlation...
To date, synchronized phasor measurements have been used mainly for power system model validation, postevent analysis, real-time display, and other similar activities. However, synchrophasors have a greater potential than monitoring and visualization. Synchrophasors will increasingly contribute to the reliable and economical operation of power systems as real-time control and protection schemes become...
In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated...
Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for asynchronous cooperative communications. They show that certain of the binary space-time trellis codes derived from the Hammons-El Gamal stacking construction are delay tolerant and can be used in the multilevel code constructions by Lu and Kumar to produce delay tolerant space-time codes for...
Expected growth in use and implementation of wireless sensor networks (WSNs) in different environments and for different applications creates new security challenges. In WSNs, a malicious node may initiate incorrect path information, change the contents of data packets, and even hijack one or more genuine network nodes. As the network reliability completely depends on individual nodespsila presence...
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