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In this paper, we study the delay/throughput trade-off with opportunistic relaying over channels with random connections, in which the channel connections are independent and identically distributed (i.i.d.). Previous work~\cite{CA:07} which proposed an opportunistic relaying scheme has focused on the throughput analysis only, we show that the opportunistic relaying scheme provides an upper bound...
Beaconless position-based forwarding protocols have recently evolved as a promising solution for packet forwarding in wireless sensor networks. However, as the network density grows, the overhead incurred grows significantly. As such, end-to-end energy and delay performance is adversely impacted. Motivated by the need for a forwarding mechanism that is more tolerant to growth in node density, an alternative...
The time-varying feature of wireless channels usually makes the hard delay bound for data transmissions unrealistic to guarantee. In contrast, the statistically-bounded delay with a small violation probability has been widely used for delay quality-of-service (QoS) characterization and evaluation. While existing research on the statistical-delay control mainly focused on the single-hop links, in this...
An analytical framework for the link-level end-to-end (e2e) queueing performance evaluation in a multiuser wireless relay network with automatic repeat request (ARQ)-based error control is presented. The e2e system consisting of a base station, a relay station, and multiple users is modeled as a probabilistic tandem of two finite queues for the relay and each user. The transmissions from the users...
The performance of opportunistic forwarding in the multi-hop cognitive radio networks (CRN) is dependent on the efficient detection of spectrum opportunities and the diversity of relay links. To find appropriate spectrum opportunities, effective spectrum sensing is essential in a CRN, especially under highly dynamic channel conditions. In this paper, a novel channel metric is proposed to determine...
Recently developments in the field of telecommuni-cations and network technology has been formed new paradigm shift in defense weapon system. The military also developing the Tactical Information Communication Network (TICN) system to meet the changing aspects of these wars. To equip its function from the battlefield, TICN system have to be received real-time information from the battlefield troop,...
Mobile data relay agents (or ferries) have the potential to build wireless backbones over which sparsely located, unconnected nodes can communicate in a delay-tolerant fashion. Paths taken by agents determine the quality of such delay tolerant networks (DTNs). We consider the problem of determining agent paths that minimize the maximum pair wise latency in the network. We introduce the concept of...
Hybrid cellular-ad hoc network is the combination of cellular networks and ad hoc networks. Such a network is addressed to increase spatial reuse and save deployment cost. In the literature, most researchers paid attention to technical issues such as architecture and capacity of hybrid networks. In fact, before this kind of hybrid network becomes practical, some commercial issues should also be considered...
This paper addresses the medium access control (MAC) and physical (PHY) cross-layer design of a time-division multiple access protocol (TDMA) where users with good channels are allowed to relay the packets of other users with less favorable conditions. All signals are combined at the central node using signal processing tools in order to achieve diversity. The work is focused on an asymmetrical scenario...
Future mobile tactical networks are being developed to support an increased variety of data services (e.g. Blue Force Tracking, intelligence image or video reporting) in addition to the more traditional voice services. Such networks rely on an IP-based MANET stack, running over a UHF (Ultra-High Frequency) radio interface. Unlike legacy VHF (Very-High Frequency) radios, characterized by low bitrates...
This paper describes the micro-architecture and circuit techniques for building multipliers with micro-electromechanical (MEM) relays. By optimizing the circuits and micro-architecture to suit relay device characteristics, the performance of the relay based multiplier is improved by a factor of ∼8× over any known static CMOS-style implementation, and ∼4× over CMOS pass-gate equivalent implementations...
We consider cooperative communications where nodes forward information for each other to achieve reliable communication. Cooperative communication is realized through various protocols such as Decode-and-Forward which are primarily designed with the assumption that nodes are always willing to cooperate. However, in practical systems nodes may violate the rules of cooperation with the selfish intention...
This article investigates the efficacy of a joint-design of adaptive modulation and coding (AMC) at the physical (PHY) layer with an adaptive Rmax-truncated selective-repeat automatic repeat request (ARQ) protocol at the medium access control (MAC) layer to maximize the throughput of cooperative amplify-and-forward (CAF) relay networks under prescribed delay and/or error performance constraints. Specifically,...
We consider Quality-of-Information (QoI) aware transmission policies in the presence of time-varying links in a mobile ad hoc network. QoI, tailored for military tactical networks, is defined by a set of attributes relevant to the application. Time-varying nature of links in practical networks leads to uncertainty in evaluating QoI utility to be delivered to end users. This delivered-QoI utility is...
This is the second in a two-part series of papers on statistical performance analysis of a general cross-layer automatic repeat request (ARQ) cooperative diversity (ACD) system. In order to obtain the theoretical formulas of end-to-end performance parameters, we develop a time division multiple access (TDMA)-based absorbing Markov model to help find all possible transition probabilities of each transmission...
In this paper, the energy efficiency of cooperative ARQ transmission in Amplify-and-Forward (AF) relay networks is discussed. The average total energy consumed per bit for cooperative ARQ under Quality of Service (QoS) constraints is formulated. With numerical method, the objective is optimized over the transmission data rate, the transmit power of the source and the relay, given fixed maximum retransmission...
Cognitive radio (CR) is an exciting technology to improve spectrum utilization. However, spectrum availability can change very fast due to primary user's activity, which makes most of existing CR routing protocols fail to work because they are designed for cognitive radio networks (CRNs) with slow variation of spectrum availability. Opportunistic routing is a promising routing paradigm for CRNs with...
Delay tolerant networks are intermittently connected. In this paper, we propose a DTN routing scheme EBR. The scheme is based on the idea of exploiting inter-contact time between mobile nodes to predict the number of nodes with no copy a node will encounter within the expected delay. In EBR, every node with message copies dynamically chooses the number of copies by itself. We evaluate the performance...
Supporting high mobility is essential to mobile ad hoc networks in a wide range of emerging applications such as vehicular networks. Communication links of an established communication path that extends between source and destination nodes are often broken under a high mobility environment. Although a new communication route can be established when a break in the communication path occurs, repeatedly...
In this paper, we propose a new scheduler able to extend the wireless coverage by using an incentive approach for potential mobile relaying nodes. Indeed, the cost of cooperation can be expensive in terms of QoS and energy consumption which do not motivate the nodes to cooperate. Our incentive approach rewards the cooperative nodes. The percentage of cooperation is considered in the QoS management...
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