21,601 research outputs found

    Multi-Antenna Assisted Virtual Full-Duplex Relaying with Reliability-Aware Iterative Decoding

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    In this paper, a multi-antenna assisted virtual full-duplex (FD) relaying with reliability-aware iterative decoding at destination node is proposed to improve system spectral efficiency and reliability. This scheme enables two half-duplex relay nodes, mimicked as FD relaying, to alternatively serve as transmitter and receiver to relay their decoded data signals regardless the decoding errors, meanwhile, cancel the inter-relay interference with QR-decomposition. Then, by deploying the reliability-aware iterative detection/decoding process, destination node can efficiently mitigate inter-frame interference and error propagation effect at the same time. Simulation results show that, without extra cost of time delay and signalling overhead, our proposed scheme outperforms the conventional selective decode-and-forward (S-DF) relaying schemes, such as cyclic redundancy check based S-DF relaying and threshold based S-DF relaying, by up to 8 dB in terms of bit-error-rate.Comment: 6 pages, 4 figures, conference paper has been submitte

    Performance evaluation of different CRL distribution schemes embedded in WMN authentication

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    Wireless Mesh Networks (WMNs) have emerged as a promising technology to provide low cost and scalable solutions for high speed Internet access and additional services. In hybrid WMNs, where mesh clients also act as relaying agents and form a mesh client network, it is important to provide users with an efficient anonymous and accountable authentication scheme. Accountability is required for the malicious users that are to be identified and revoked from the network access and related services. Promising revocation schemes are based on Certification Revocation Lists (CRLs). Since in hybrid WMNs mesh clients also authenticate other clients, distribution of these CRLs is an important task. In this paper, we propose and examine the performance of different distribution schemes of CRLs and analyze authentication performance in two scenarios: in one scenario all mesh routers and mesh clients obtain CRLs and in the second one, CRLs are held only by the mesh routers and mesh clients acting as relaying agents require CRL checking to be performed from the router in authenticating another client

    DMT Optimal Cooperative Protocols with Destination-Based Selection of the Best Relay

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    We design a cooperative protocol in the context of wireless mesh networks in order to increase the reliability of wireless links. Destination terminals ask for cooperation when they fail in decoding data frames transmitted by source terminals. In that case, each destination terminal D calls a specific relay terminal B with a signaling frame to help its transmission with source terminal S. To select appropriate relays, destination terminals maintain tables of relay terminals, one for each possible source address. These tables are constituted by passively overhearing ongoing transmissions. Hence, when cooperation is needed between S and D, and when a relay B is found by terminal D in the relay table associated with terminal S, the destination terminal sends a negative acknowledgment frame that contains the address of B. When the best relay B has successfully decoded the source message, it sends a copy of the data frame to D using a selective decode-andforward transmission scheme. The on-demand approach allows maximization of the spatial multiplexing gain and the cooperation of the best relay allows maximization of the spatial diversity order. Hence, the proposed protocol achieves optimal diversitymultiplexing trade-off performance. Moreover, this performance is achieved through a collision-free selection process

    Synchronous Relaying Of Sensor Data

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    In this paper we have put forth a novel methodology to relay data obtained by inbuilt sensors of smart phones in real time to remote database followed by fetching of this data . Smart phones are becoming very common and they are laced with a number of sensors that can not only be used in native applications but can also be sent to external nodes to be used by third parties for application and service development
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