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Multiple Accesses Broadcasting (MABC) is a spectral efficient protocol in two-way relay channel (TWRC). The drawback of this protocol in decode-and-forward (DF) mode is decoding complexity at the relay's side. Erroneous decoding at the relay can bring about error propagation that leads to performance degradation in all of the relay networks operating in the DF mode. In this paper, we propose ML detection...
We consider the performance of small-scale heterogeneous cooperative networks in which some nodes can transmit and/or receive using channels not available to other nodes, i.e., multimodal communication networks. As an example, we assume the presence of an additional wired channel in a conventional diamond relay network operating under the Laneman protocol, and we find analytical expressions for outage...
We propose two scheduling protocols which are applicable to two-hop relay networks based on mobile WiMAX system: the first protocol adopts a persistent scheduling (PS) scheme in both hops, called the PS-PS protocol, while the second protocol adopts the PS scheme only in the first hop and the dynamic scheduling (DS) scheme in the second hop, called the PS-DS protocol. We optimize the above two protocols...
We evaluate the outage probability and the spectral efficiency of cooperative multi-hop networks, where L relay nodes are placed at each hop and an MDS (Maximum Distance Separable) code of coding rate 1/L is employed at the link-layer. A codeword of the MDS code is partitioned into L blocks. When each relay node receives two or more codeword blocks of the MDS code, it aggregates the blocks, corrects...
We study the power allocation algorithms in the case of multi-source multi-relay (MSMR) amplify-and-forward wireless cooperative network in this paper. In this MRMS system, we consider that multiple users would communicate with one destination node with the help of multiple relay nodes in the same time. To guarantee the quality-of-service (QoS) for all the users and reduce the power consumption, we...
Three low-complexity relay-selection strategies, namely, selective amplify and forward (S-AF), selective decode and forward (S-DF), and amplify and forward with partial relay selection (PRS-AF) in a spectrum-sharing scenario are studied. First, we consider a scenario where perfect channel state information (CSI) is available. For these scenarios, the respective asymptotic outage behaviors of the secondary...
In this paper, we analyze the bit error rate (BER) performance of a single relay selection with network coding (S-RS-NC) scheme in two-way relay channels. In this scheme, two source nodes first broadcast their information to the relays sequentially. A single relay which optimizes the system performance is selected. The selected relay decodes the received signals from two sources, performs network...
We propose a cooperative orthogonal space-time block codes (OSTBC) transmission scheme in the adaptive-gain amplify-and-forward MIMO relaying with NS source antennas, NR relay antennas, and ND destination antennas, and analyze the asymptotic performance of the proposed scheme. Specifically, we explore the instantaneous channel state information (CSI) of source-to-relay channel and design an OSTBC...
One proven solution to improve the reliability of a wireless channel is to use relays. We focus on the estimate-and-forward (EF) relay protocol where the relay node estimates the source symbol and then forwards it to the destination. We assume the soft information sent by the relay is the expected value of the symbol transmitted by the source. With bit-error-rate (BER) as a metric, we show that EF...
We consider a wireless network in which a source terminal communicates with a destination and a relay terminal is occasionally present in close proximity to the source without source's awareness, suggesting oblivious protocols. We incorporate a two-layer broadcast approach into two cooperative strategies based on the decode-and-forward scheme - Sequential Decoded-and Forward (SDF) and the Block-Markov...
Power saving is an important issue in wireless networks. This paper proposed an energy-efficient cooperative relay selection scheme that utilized the transmission power more efficiently in cooperative relaying systems. The nodes in the network were deployed with multiple antennas and the decode-and-forward relaying protocol was used. The optimization problem of energy efficiency in cooperative relaying...
For optimizing the performance of cooperative communication system, it presents a multi-relay amplify forwarding (AF) and decoded forwarding (DF) cooperation node selection algorithm based on the residual energy, considering jointly the residual energy information of nodes and channel state information(CSI) to optimize network lifetime, using the weighting function to select the relay set. Simulation...
Cooperative communication has been recently proposed as a way to improve the performance of wireless communication. However, due to the half duplex constraint, most of the relay networks face a fundamental challenge in terms of multiplexing loss. In this paper, we present an adaptive cooperation via relay selection (ACRS) protocol that improves spectral efficiency. This protocol lets the source transmit...
In downlink relay systems, the conventional straightforward relaying scheme named decode-and-forward (DF) protocol is used at relay station (RS) to decode the data received from base station (BS) and forward the decoded data to the mobile station (MS) to improve the spatial diversity gain. However, conventional DF mode is spectral inefficient and not capacity optimal since the wireless channels in...
Adaptive network coded cooperation (ANCC) scheme has been shown to have better performance than the conventional repetition-based schemes and the space-time coded cooperation (STCC) frameworks for data transmissions from a large collection of terminals to a common destination in large wireless networks. However, the random selection strategy for ANCC protocol may generate many short cycles in the...
Cooperative communication exploits the broadcast nature of wireless channel and uses relay nodes to provide better reliability and higher data rates without increasing power and bandwidth. In this paper, the energy analysis of the asynchronous polarized cooperative (APC) scheme is performed. APC employs multiple antennas at the relay and destination nodes to achieve full duplex amplify-and-forward...
Considering the issues involved in the multiple relaying cooperation such as the perfect synchronization and high complexity, some single-relay selection schemes are presented in this paper for two-way relaying networks, where this network is consisted of two source nodes and multiple relay nodes, each node with single antenna. The novel single-relay selection schemes based on the transmission rate...
In this paper, we investigate the optimal power and time allocation for a wireless relay network, called BCFR (Broadcasting Channel with Fixed Relay), where the relay node is limited by the half-duplex operation. Introducing a relay in two-node broadcasting channel for a node which has a link of bad quality or requires higher transmission rate enlarges the rate region with well-designed power and...
In this paper, we investigate the impact of network coding at the relay node on the stable throughput rate in multicasting cooperative wireless networks. The proposed protocol adopts Network-level cooperation, as in contrast to the traditional physical layer cooperative protocols; and in addition, it uses random linear network coding at the relay node. The traffic is assumed to be bursty and the relay...
In cooperative systems, the fractional incremental relaying (FIR) protocol can achieve higher spectral efficiency than the traditional incremental relaying (IRL) protocol by transmitting a fraction of packet, instead of the whole packet, at a time when retransmission is needed. The incremental redundancy (IRD) protocol can also be utilized when retransmission is necessary. Based on the two protocols,...
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