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Node localization has long been established as a key problem in the sensor networks. Self-mapping in wireless sensor network which enables beacon-based systems to build a node map on-the-fly extends the range of the sensor network's applications. A variety of self-mapping algorithms have been developed for the sensor networks. Some algorithms assume no information and estimate only the relative location...
In this paper, we consider the power allocation problem in a network coded multiuser two-way relaying network, where multiple pairs of users exchange information with the help of a relay node. An auction-based power allocation scheme is proposed to solve the power competition among multiple user pairs. To maximize the utility of the whole pair, each two users in the pair bid as a single player, with...
Opportunistic Network Coding (ONC) has attracted much attention recently. The main improvement of ONC over the traditional network coding is that ONC allows the encoding node to decide whether it employs network coding based on the status of all its input streams. However, due to the nature of fading, wireless links may not always be reliable. Thus, the performance gain of ONC over traditional methods...
Aiming at improving the QoS performance over fading channels, this paper presents an analysis of the effective capacity for a relay-assisted communication system which utilizes a cooperative packet retransmission protocol at the link-layer in conjunction with AMC-based multi-rate transmission at the physical layer. In the considered model, a source (S) node employs AMC to transmit delay-constrained...
In this paper, we propose a new multiple relay selection scheme with the availability of outdated channel state information (CSI) for decode and forward (DaF) relay systems, namely the plus normalized threshold opportunistic relay selection ($N$+NT-ORS). In particular, we first opportunistically select best relays out of all relays in the decoding subset with respect to CSI. Then the ratios of...
the MAC scheduler is an important and crucial entity of the Long Term Evolution (LTE) and is responsible for efficiently allocating the radio resources among mobile users who have different QoS demands. The scheduler takes different considerations into account such as throughput and fairness when deciding the allocation of the scarce radio resources. LTE is an all IP packet system in which guaranteeing...
In this paper, we study distributed channel assignment in wireless networks with applications to peer discovery in ad hoc wireless networks. We model channel assignment as a coloring problem for spatial point processes in which n nodes are located in a unit cube uniformly at random and each node is assigned one of K colors, where each color represents a channel. The objective is to maximize the spatial...
In this paper, we study the diversity-multiplexing tradeoff (DMT) of two-way relay channels (TWRC) with multi-antenna relay at finite signal-to-noise ratio (SNR). A two-phase decode-and-forward (DF) relay protocol and Rayleigh fading environment are considered. We first derive upper and lower bounds on the outage probability. These bounds are very tight for all practical SNR regions. Based on these...
We consider a wireless communication model where a large number of transmitter-receiver pairs share a common Rayleigh fading channel without any coordination between them. The performance of a simple coexistence etiquette is analyzed in details, where packets are allowed to be transmitted from a given terminal only if the signal-to-interference-plus-noise ratio (SINR) at their intended receiver exceeds...
A distributed space-time block code (STBC) based on a decode-and-forward (DF) protocol is proposed for two-path successive relaying. By making the two relay nodes transmit and listen in turn, the proposed distributed STBC can achieve not only full rate but also full diversity when the relay nodes can correctly decode the information symbols from the source node and when the inter-relay channels are...
The opportunistic cooperation schemes, where only the “best” relay is selected to forward the message, are well performed in outage probability but with poor fairness among relays. In this paper, we introduce the concept “outage priority based fairness” (OPF), aiming at improving the fairness appropriately without outage performance deterioration. A novel cooperation scheme is proposed to meet the...
In this paper, we investigate the performance of selection cooperation in the presence of imperfect channel estimation. In particular, we consider a cooperative scenario with multiple relays and amplify-and-forward protocol over frequency flat fading channels. In the selection scheme, only the "best" relay which maximizes the effective signal-to-noise ratio (SNR) at the receiver end is selected...
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...
This paper studies the performance limits of two-way relay channel (TWRC) at finite signal-to-noise ratio (SNR) in Rayleigh fading environment. A two-phase decode-and-forward (DF) protocol is considered. We first derive closed-form expressions for both outage probability and diversity-multiplexing tradeoff (DMT). Our results are general and suitable for any time sharing and any rate allocation in...
Fairness and system throughput, influenced by wireless interference, are major objectives of resource allocation in wireless networks. Whereas traditionally max-min fairness protocols have been developed for wired networks (where interference is not a factor for network performance), in this paper we investigate the problem of flow routing and fair bandwidth allocation under the constraints of the...
This paper proposes a Multi-relay Cooperative Automatic Repeat ReQuest protocol (MC-ARQ) for IEEE 802.11 based wireless networks. The proposed distributed relay selection scheme not only selects the best relays but also solves the collision problem among multiple contending relays, by sorting the relays in the network according to their instantaneous channel quality with the destination node. No prior...
In this paper, we study the application of cooperative diversity to wireless broadcast channels, a fundamental building block of wireless communication networks. Several cooperative broadcast protocols will be proposed, and information theoretic metrics are developed to facilitate performance evaluation. Provided that there is no direct S-D link, the proposed protocols can achieve a multiplexing gain...
Adaptive modulation has been widely adopted in broadband wireless communication systems to improve spectrum efficiency. On the other hand, user cooperative diversity has been investigated to improve system coverage and efficiency. How to take the advantage of adaptive modulation for user cooperative transmissions to maximize network throughput under the constraint of the bit error rate (BER) requirement...
This paper addresses the problem of discovering least interfering paths in the context of multipath routing in multihop wireless networks using the SINR based interference model. Whereas traditionally interference has been quantified using the protocol model, we propose a disjoint multipath interference aware routing algorithm, known as DMPR:SINR, using a weighted SINR conflict graph to quantify interference...
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