Distributed differential beamforming and power allocation for cooperative communication networks

Many coherent cooperative diversity techniques for wireless relay networks have recently been suggested to improve the overall system performance in terms of the achievable data rate or bit error rate (BER) with low decoding complexity and delay. However, these techniques require channel state information (CSI) at the transmitter side, at the receiver side, or at both sides. Therefore, due to the overhead associated with estimating CSI, distributed differential space-time coding techniques have been suggested to overcome this overhead by detecting the information symbols without requiring any (CSI) at any transmitting or receiving antenna. However, the latter techniques suffer from low performance in terms of BER as well as high latency and decoding complexity. In this paper, a distributed differential beamforming technique with power allocation is proposed to overcome all drawbacks associated with the later techniques without needing CSI at any antenna and to be used for cooperative communication networks. We prove through our analytical and simulation results that the proposed technique outperforms the state-of-the-art techniques in terms of BER with comparably low decoding complexity and latency

A low complexity distributed differential scheme based on orthogonal space time block coding for decode-and-forward wireless relay networks

This work proposes a new differential cooperative diversity scheme with high data rate and low decoding complexity using the decode-and-forward protocol. The proposed model does not require either differential encoding or channel state information at the source node, relay nodes, or destination node where the data sequence is directly transmitted and the differential detection method is applied at the relay nodes and the destination node. The proposed technique enjoys a low encoding and decoding complexity at the source node, the relay nodes, and the destination node. Furthermore, the performance of the proposed strategy is analyzed by computer simulations in quasi-static Rayleigh fading channel and using the decode-and-forward protocol. The simulation results show that the proposed differential technique outperforms the corresponding reference strategies

Hybrid location-based routing in ad-hoc wireless networks

This thesis is concerned with the development and analysis of a newhybrid location-based routing protocol for ad hoc wireless networks.A feature that permeates throughout this work is the use of all availablelocation information within the network in order to minimize therouting overhead. Such minimization leads to an enhanced scalabilityperformance for the network.More directly, we can say the main contribution of this thesis is thatit introduces a new Hybrid Location-based Ad-hoc Routing protocol(HLAR) designed specifically with optimal scalability performance inmind. The HLAR protocol combines features of reactive routing withgeographic routing in such a manner so as to efficiently use all locationinformation available, and to gracefully exit to reactive routing as thelocation information degrades. An important aspect of HLAR is thatit can be spatially dependent - meaning different physical areas of thenetwork may utilize different routing procedures simultaneously. Akey feature of HLAR is the consideration given to realistic locationerrors within the protocol design.Through detailed analysis and detailed Monte Carlo simulations weinvestigate the scalability of the HLAR protocol within different environmentsand different target applications. A particular focus is theuse of HLAR within the Vehicular ad hoc Network (VANET) environment.We demonstrate how HLAR is the ideal routing protocolfor emerging VANET systems in that it produces effectively optimalscalability over a wide range of the anticipated environment variables.We demonstrate that similar scalability performance is expected forslower moving pedestrian ad hoc networks.We also introduce a simplified version of HLAR, which we refer toas Geographic Routing with Congestion Avoidance (GRCA), which isspecifically designed for VoIP applications. The GRCA protocol couplesa congestion avoidance algorithm specifically designed for VoIP,to a greedy geographic forwarding algorithm in order to deliver twokey attributes that hitherto are not simultaneously present in anyother single ad hoc routing protocol. Specifically, GRCA maximizesVoIP capacity whilst remaining scalable, and obtains an up-to factorof two improvement in VoIP capacity relative to other well known adhoc routing protocols

A low complexity distributed differential scheme based on orthogonal space time block coding for decode-and-forward wireless relay networks

This work proposes a new differential cooperative diversity scheme with high data rate and low decoding complexity using the decode-and-forward protocol. The proposed model does not require either differential encoding or channel state information at the source node, relay nodes, or destination node where the data sequence is directly transmitted and the differential detection method is applied at the relay nodes and the destination node. The proposed technique enjoys a low encoding and decoding complexity at the source node, the relay nodes, and the destination node. Furthermore, the performance of the proposed strategy is analyzed by computer simulations in quasi-static Rayleigh fading channel and using the decode-and-forward protocol. The simulation results show that the proposed differential technique outperforms the corresponding reference strategies