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Cooperative relay has been recognized as a promising approach for improving transmission efficiency and error performance in wireless networks. A number of realizations of cooperative relay communications, such as Amplify-and-Forward (AF), Decode-and-Forward (DF), have been proposed and the capacity gain of these replay approaches has been widely investigated. In this paper, we consider a cooperative...
In this paper we analyze performance of network coding focusing on two specific network coding schemes: XOR and random linear network coding. We have simulated different topologies and traffic patterns in order to provide better understanding of network coding behavior and its possible bottlenecks. As a part of our performance evaluation we address computational complexity of coding and decoding operations...
Enhanced Multimedia Broadcast/Multicast Service (eMBMS) is a new function defined in 3GPP Release 8 specification, which supports download delivery and streaming delivery to group users in LTE mobile networks. For download delivery, there are two mechanisms implemented in different entities to improve reliability: (1) At eBMSC (Enhanced Broadcast/Multicast Service Center), Raptor code is implemented...
In this paper we define the jointly optimum topology for the duplex transmission (uplink/downlink) in multihop cellular networks which is aware of the intercell interference and a protocol that reconfigures the optimum topology based on the observation of the temporal traffic in the network. In addition we also consider the application of network coding in cellular networks to combine the uplink and...
Cognitive radio networks (CRN) may greatly enhance the throughput based on a given bandwidth. CRN has a unique feature, consisting of uni-directional opportunistic wireless links, and packets may be cooperatively relayed from source node to destination node through one or multiple paths, while each path consists of multi-hop opportunistic wireless fading links. Effective end-to-end error control is...
In this paper, we show how to compute the Slepian-Wolf lower bound for the reconciliation of physical layer secret keys between two radio terminals. Two coding approaches, including the syndrome method and the parity method, have been proven to require the same number of bits exchanged between two terminals for the reconciliation in the noiseless environment. We also present a practical coding approach...
A classification-based method is proposed to select an optimal path for video streaming over multi-hop mesh networks. Our main contribution is translating of path selection over multi-hop networks to a standard classification problem. The classification is based on minimizing average video packet distortion at the receiving nodes. We also consider long range dependence (LRD) characteristics of variable...
To provide reliable video stream transmission over wireless networks, we propose a cross-layer design model in this paper. In the proposed model, the adaptive modulation and coding parameters at the physical layer, the ARQ parameters at the data link layer and the application-layer forward error correction (A-FEC) parameters at the application layer are jointly designed. Our objective is to maximize...
The paper addresses wireless the 2-Way Relay Channel (2-WRC) system with a Hierarchical Decode and Forward strategy. This strategy uses a Hierarchical eXclusive Code (HXC) that allows full decoding of the hierarchical symbols at the relay. The HXC represents two data sources only through the exclusive law and requires side information on the complementary data at the destination (which naturally holds...
Video streaming applications over wireless networks present many challenges owing to the high packet error rate and the error characteristics of consecutive packets. In order to solve these problems, this paper proposes a cross-layer Unequal Error Protection (UEP) Forward Error Correction (FEC) mechanism with an interleaved strategy for video streaming over wireless networks. The proposed novel UEP...
This paper investigates the downlink burst allocation problem in IEEE 802.16 OFDMA system. In order to increase the subchannel utilization and to improve the network throughput, a channel-aware renumbering (CSR) scheme and a channel-aware downlink burst allocation (CDBA) scheme are proposed in this paper. CSR considers the difference among subchannel qualities of MSs and logically renumbers the subchannels...
The two-phase MIMO NC (network coding) scheme can be used to boost the throughput in a two-way relay channel in which nodes are equipped with multiple antennas. The obvious strategy is for the relay node to extract the individual packets from the two end nodes and mix the two packets to form a network-coded packet. In this paper, we propose a new scheme called MIMO PNC (physical network coding), in...
It has been shown in the literature that network coding can improve the transmission efficiency of wireless broadcasting as compared to traditional ARQ schemes. In this paper, we propose an improved network coding scheme that can asymptotically achieve the theoretical lower bound on transmission overhead for a sufficiently large number of information blocks. The proposed scheme makes use of an index...
Before vehicle-to-vehicle-communication-based road safety becomes a reality, one of the challenges that needs to be resolved is efficient and timely recovery of safety packets that may be lost due to reception failure. Various types of retransmission-based recovery protocols have been proposed in the literature to address this problem. Although, retransmission can help recover some of the lost packets,...
In this paper, a transmission strategy of fountain codes over cooperative relay networks is proposed. When more than one relay nodes are available, we apply network coding to fountain-coded packets. By doing this, partial information is made available to the destination node about the upcoming message block. It is therefore able to reduce the required number of transmissions over erasure channels,...
In this paper, a low-complexity protocol for the K-parallel-path multihop channel is proposed. This protocol is based on a smart path selection combined with a small space-time code. It is proven to achieve full rate and full diversity, and to reach the optimum diversity-multiplexing gain tradeoff d*(r)=K(1-r)+. Some implementation issues such as the frame length or interferences between paths are...
Although the established capacity results for the classic three-node relay channel rely on the assumption of full-duplex relay nodes, it's practically difficult for radio transceivers to support simultaneous signal transmission and reception. Time-division half-duplex relay strategies have thus been proposed to address this limitation. Amplify-and-forward (AF) and decode-and-forward (DF) are two well-known...
In this paper, we present a practical adaptive multiple-input multiple-output (MIMO) transmission approach for broadband wireless multiuser systems. The proposed scheme adaptively switches between open-loop and closed-loop MIMO modes, depending on the users' channel conditions and required rates, as a means to enhance the system throughput and performance. Each mode is a combination of a MIMO transmission...
A novel combination of block spread orthogonal frequency division multiple access (BS-OFDMA) with space-time coded multiple input multiple output (STC MIMO) scheme is proposed for broadband wireless access uplink transmission. Using complex exponential spreading sequences, the block spreading technique can efficiently generate precoded OFDMA signal to exploit frequency diversity. An Alamouti STC MIMO...
We consider the joint exploitation of coding and diversity techniques to achieve efficient, reliable wireless transmission. The system of interest comprises a powerful non-binary low-density parity-check (LDPC) code that will be soft-decoded to supply strong error protection, a quadratic amplitude modulator (QAM) that directly takes in the non-binary LDPC symbols and will be soft-demodulated, and...
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