The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Network life time maximization is becoming an important design goal in wireless sensor networks. Energy harvesting has recently become a preferred choice for achieving this goal as it provides near perpetual operation. We study such a sensor node with an energy harvesting source and compare various architectures by which the harvested energy is used. We find its Shannon capacity when it is transmitting...
In this paper, we exploit cooperative diversity, channel diversity and multi-user diversity gains in an OFDMA-based wireless relay network by studying a joint channel and relay assignment problem. This problem turns out to be NP-hard. First, a mixed integer linear programming formulation is presented to provide optimal solutions. We then present a constant factor approximation algorithm and two heuristic...
In this paper, we investigate the convergence behavior of the primal-dual scaled gradient algorithm (PDSGA) for solving distributed network utility maximization problems under time-varying fading channels. Our analysis shows that the proposed PDSGA converges to a limit region rather than a point under FSMC channels. We also show that the asymptotic tracking errors are given by O(T̅/N̅), where T̅ and...
This paper is concerned with the performance analysis of decode-and-forward cooperative diversity wireless communication systems over general fading channels. New exact expressions are derived for the average mutual information with multiple relay nodes and arbitrary power allocations. This facilitates evaluating the performance of several suboptimal power allocation schemes which distribute the total...
We consider the energy-efficient network resource allocation that minimizes a cost function of average user powers for multi-hop wireless networks. A class of fair cost functions is derived to balance the tradeoff between efficiency and fairness in energy-efficient designs. Based on such cost functions, optimal routing, scheduling and power control schemes are developed. Relying on stochastic optimization...
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...
It has been shown that channel state information (CSI) at transmitter can significantly increase the performance of a relay system. However, most of the existing designs assume perfect CSI at the transmitters. Since most practical systems can only obtain partial CSI at the transmitters, it is necessary to analyze the relay channels with limited CSI feedback. Our objective in this paper is to find...
Capacity and coverage of a Frequency Division Multiple Access (OFDMA) network can be greatly enhanced by dynamically allocate the radio transmission resources. By including the radio resources of cooperative nodes and taking into account the fairness issue, we present a simple suboptimal solution to the problem of radio resource allocation in relaybased OFDMA cellular systems. We restrict our investigation...
We consider power allocation (PA) and relay positioning in a dual-hop decode-and-forward relaying system over Nakagami-m fading channels. We investigate adaptive power allocation (PA) with fixed relay location, optimal relay location with fixed power allocation and joint optimization of the PA and relay location under transmit power constraint in order to minimize outage probability and average error...
In this paper, we investigate the asymptotic e-outage capacity of a half-duplex large fading relay network, which consists of one source node, one destination node, and N relay nodes. The relay nodes are assumed to be randomly deployed in a given area and under fatal independent random attacks with probability p. With a total power constraint on all the nodes, we examine the e-outage rate of the amplify-and-forward...
This paper derives an optimal power allocation (PA) to maximize the effective average signal-to-noise ratio (SNR) of distributed space-time coding (DSTC) in wireless relay networks, where the locations of the relays can be anywhere between the source and destination. It is first shown that in maximizing the average SNR, not all the relays might be active, and hence the code performance might be compromised...
We present and analyze two different power allocation strategies for considerably improving the average bit error rate (BER) performance of wireless multihop systems with an arbitrary number of regenerative relay stations. In both cases, the power allocation is done based on instantaneous channel state information subject to an overall sum power constraint as well as possible additional per-node power...
An amplify-and-forward relaying network where the source is orthogonal to all the relays but the relays are nonorthogonal (SORNAF) is studied. The problem of relay power optimization in a SORNAF relaying scheme is formulated as a nonconcave fractional program. Selection amplify-and-forward (SAF) relaying is a possible power allocation strategy previously proposed for the SORNAF scheme. A necessary...
In this paper, we provide a saturation throughput analysis of the IEEE 802.11 protocol at the data link layer by including the impact of both transmission channel and capture effects in Rayleigh fading environment. Impacts of both non-ideal channel and capture effects, specially in an environment of high interference, become important in terms of the actual observed throughput. As far as the 4-way...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.