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We consider minimum-energy routing in a wireless network. We assume the use of ideal rateless codes, so that a node can accumulate transmission rates from the transmission of previous nodes on the routing path. Mutual information accumulation has significant advantages when compared with classical cooperative schemes that use energy accumulation. However, the resource allocation problem becomes more...
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...
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...
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...
In this paper, we address two issues in multihop wireless networks—poor end-to-end delay performance and high per-slot computational overhead of the classical max-weight algorithm. To reduce the end-to-end delay, we first propose a simple modification to the classical maximum weight scheduling algorithm that promotes the use of shorter paths by the packets. The significantly lower delays are shown...
We consider a cooperative relay network where a source node communicates to a destination node with the help of multiple relay nodes (RNs). RNs are assumed to be able to work in either active mode or sleep mode. To minimize the total energy consumption, working modes of RNs and power allocation need to be optimized. Based on the time scales of mode transition, we formulate two different energy minimization...
We consider resource allocation in the 3GPP Long Term Evolution (LTE) cellular uplink, which will be the most widely deployed next generation cellular uplink. The key features of the 3GPP LTE uplink (UL) are that it is based on a modified form of the orthogonal frequency division multiplexing based multiple acess (OFDMA), which enables channel dependent frequency selective scheduling, and that it...
In the Floating Content application, mobile nodes collectively store and disseminate messages relevant to a certain area by using the principles of opportunistic networking. The system operates in best effort fashion relying solely on the nodes located in the area of interest, which is referred to as the anchor zone of the message. Past work has focused on mobility models, where the nodes are constantly...
We analyze a cognitive radio network where the primary users (PUs) and cognitive radio (CR) devices are distributed over the two-dimensional plane according to two independent homogeneous Poisson processes. Any CR that lies within the detection region of some PU switches to a different channel in order to prevent causing harmful interference at the PU. Using the concepts of stochastic geometry, we...
In this paper, we introduce a new population model. Taking the geometry of cities into account by adding roads, we build a Cox process driven by a Poisson line tessellation. We perform several shot-noise computations according to various generalizations of our original process. This allows us to derive analytical formulas for the uplink coverage probability in each case.
Adaptive frequency hopping (AFH) as proposed, e.g., in IEEE 802.15.2 aims at increasing system reliability in the presence of quasi-static external interference. Practical approaches require autonomous sensing of the interference environment, with the measurements containing both external interference and network self -interference. In prior work, a simplistic model for AFH-based ad hoc networks was...
An ubiquitous assumption when modeling base stations in cellular networks is to consider deterministic lattices, usually hexagonal ones. On the other hand, mobile users are usually modeled by a Poisson point process. Both the assumptions are too simplistic. In the first part of the lecture we will present a few evidences and consequences of the fact that shadowing, that is signal power loss due to...
In this paper, we investigate user grouping for cooperative scheduling in a two-cell network. When the number of transmitters grows large, the complexity of the Hungarian algorithm optimum for user pairing becomes unaffordable in real-time systems. We consider user grouping algorithms maximizing the network sum rate in cells with a massive number of terminals and/or sensors. We provide a suboptimal...
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...
Femtocell networks are about to be extensively deployed with the aim of providing substantial improvements to cellular coverage and capacity. However, their deployment is nontrivial because of the extra interference that the femtocell nodes cause to the macrocell nodes with which they share the same portion of the spectrum. This paper proposes a non-cooperative power control approach for interference...
In this paper, we consider a heterogeneous network (eg. Macrocells overlaid with small cells), where users associated with their respective base stations (BS) demand certain rates. These users interfere with each other and one needs an algorithm that satisfies the demands irrespective of the number of interferers and the amount of interference (whenever the demands are within the achievable limits)...
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