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Most current wireless IEEE 802.11 networks rely on a power-threshold based carrier-sensing multi-access (CSMA) mechanism to prevent packet collisions, in which a transmitter permits its transmission only if the locally measured aggregate interference power from all existing transmissions is below a prespecified power-sensing threshold. However, such a mechanism can not completely guarantee interference-safe...
It is by now well-known that wireless networks with file arrivals and departures are stable if one uses α-fair congestion control and back-pressure based scheduling and routing. In this paper, we examine whether α-fair congestion control is necessary for flow-level stability. We show that stability can be ensured even with very simple congestion control mechanisms, such as a fixed window size scheme...
Backlog-based wireless access schemes are simple and inherently distributed, yet provide a striking capability to match the optimal throughput performance of centralized scheduling mechanisms in a wide range of scenarios. Unfortunately, the type of activation rules for which throughput optimality has been established, may result in excessive backlogs and delays. The use of more aggressive/persistent...
The mean packet delay (MPD) of multi-hop wireless ad-hoc networks (WANET) has a major impact on the networks performance and quality of service. In this paper we analyze the performance of slotted carrier sense multiple access (CSMA) WANET under a MPD constraint. The MPD is determined by the mean number of hops between sources and destination pairs, the back-off probability and the outage probability...
This paper studies the optimal transmission policy for a Gilbert-Elliott Channel. The transmitter has two actions: sending aggressively or sending conservatively, with rewards depending on the action chosen and the underlying channel state. The aim is to compute the scheduling policy to determine which actions to choose at each time slot in order to maximize the expected total discounted reward. We...
The liberalization of wireless spectrum markets has been envisioned as a method for improving mobile communication services and accommodating the increasing traffic volumes of wireless users. It has been assumed that competition among operators will foster optimal utilization of wireless spectrum and ensure the provision of cost-efficient wireless services to users. However, spectrum markets often...
The goal of this paper is to investigate how incomplete information on the fading channel gains impacts transmission parameters. We consider in an OFDM network with transmitters and jammers. To deal with this situation we employ a Bayesian approach by introducing different type of user and jammer corresponding to their knowledge of the network environment. To get an insight of the problem, the signal...
This paper addresses the joint pricing and network selection problem in cognitive radio networks, considering both the point of view of network users and the Primary Operator. The problem is formulated as a Stackelberg (leader-follower) game where first the PO sets the network subscription price to maximize its revenue. Then, users perform the network selection process, deciding whether to pay for...
We propose a new linear-regression model for the estimation of the path-loss exponent and the parameters of the shadowing from the propagation-loss data collected by the mobiles with respect to their serving base stations. The difficulty consists in deriving the parameters of the distribution of the propagation loss with respect to an arbitrary base station from these regarding the strongest one....
We develop a framework to model and study cellular networks with randomly wandering users. Our model captures user displacement resulting from random mobility patterns and arrival positions, which in turn influences the transmission rates. We model the user movements by a random walk with exponential wandering times. Each cell is composed of disjoint (transmission) rate regions and we model each rate...
Using additional antennas and signal processing techniques to build a full-duplex radio is becoming a popular topic in the networking research community. However, additional antennas are used for MIMO (multiple input multiple output) transmissions, traditionally, and it is well-known that increasing the number of antennas on either transmitter or receiver side increases the MIMO link capacity. Therefore,...
In this paper, we develop novel two-tier interference management strategies that enable macrocell users (MUEs) to improve their performance, with the help of open-access femtocells. To this end, we propose a rate-splitting technique using which the MUEs optimize their uplink transmissions by dividing their signals into two types: a coarse message that is intended for direct transmission to the macrocell...
Since dynamic wireless networks evolve over time, optimal routing computations need to be performed frequently on time-varying network topologies. However, it is often infeasible or expensive to gather the current state of links for the entire network all the time. We provide a thorough analytical characterization of the effect of various link-state sampling strategies operating under a limited sampling...
We design fast iterative policies for resource allocation in the uplink of LTE. We generalize recent works on iterative delay and queue based scheduling policies to more general system settings. We model all constraints due to contiguous bandwidth allocation, peak transmit power and fractional power control. We design a novel mechanism for inferring the packet delays approximately from the buffer...
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