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Performance analysis of TCP-controlled long file transfers in a WLAN in infrastructure mode is available in the literature with one of the main assumptions being equal window size for all TCP connections. In this paper, we extend the analysis to TCP-controlled long file uploads and downloads with different TCP windows. Our approach is based on the semi-Markov process considered in and, but with arbitrary...
In this paper, we consider the problem of modelling the average delay in an IEEE 802.11 DCF wireless mesh network with a single root node under light traffic. We derive expression for mean delay for a co-located wireless mesh network, when packet generation is homogeneous Poisson process with rate λ. We also show how our analysis can be extended for non-homogeneous Poisson packet generation. We model...
As migration to IPv6 occurs slowly, IPv4 and IPv6 hosts will coexist for many years. We consider a specific scenario where the legacy IPv4 systems can not be upgraded and also the new systems are IPv6. The mix of IPv4 and IPv6 machines exist in the same network and both need to interoperate. We propose a novel Translator called SBIIT (Socket identifier Based IPv4/IPv6 Translator), which is based on...
Achieving optimal transmission throughput in multi-hop wireless networks is a fundamental but hard problem. The situation is aggravated when nodes are mobile. Further, multi-rate systems make the analysis of throughput more complicated. In mobile scenario, a link may break or be created as nodes are moving within communication range. `Route and schedule discovery' which is to find the optimal route...
We analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the...
In this paper, we consider the problem of modelling the average delay experienced by an application packets of variable length in a single cell IEEE 802.11 DCF wireless local area network. The packet arrival process at each node i is assumed to be a stationary and independent increment random process with mean ai and second moment ai(2). The packet lengths at node i are assumed to be i.i.d random...
In this paper, we consider the problem of scheduling in multihop wireless networks subject to interference constraints. We consider a graph based representation of wireless networks, where scheduled links adhere to the K-hop link interference model. We develop a distributed greedy heuristic for this scheduling problem. Further, we show that this distributed greedy heuristic computes the exact same...
We present a centralized integrated approach, ADWISER, for (i) managing an Internet access link bandwidth, and (ii) for enhancing the performance of an IEEE 802.11 WLAN. Our single-box approach is an extension to our previous work, where we focused on meeting TCP performance objectives over WLANs. In this work, we present a novel cascaded packet scheduling algorithm to address the issue of unfair...
We develop analytical models for estimating the energy spent by stations (STAs) in infrastructure WLANs when performing TCP controlled file downloads. We focus on the energy spent in radio communication when the STAs are in the Continuously Active Mode (CAM), or in the static Power Save Mode (PSM). Our approach is to develop accurate models for obtaining the fraction of times the STA radios spend...
This paper describes the implementation of wireless mesh nodes based on the IEEE 802.11s draft where the motivation is to build a real life mesh network. The mesh nodes developed have mesh, mesh access point and mesh portal functionalities simultaneously. The mesh nodes use different radios for mesh and access point functionalities, thus giving better service to client stations. Both reactive and...
Many basic key distribution schemes specifically tuned to wireless sensor networks have been proposed in the literature. Recently, several researchers have proposed schemes in which they have used group-based deployment models and assumed predeployment knowledge of the expected locations of nodes. They have shown that these schemes achieve better performance than the basic schemes, in terms of connectivity,...
A large part of today's multi-core chips is interconnect. Increasing communication complexity has made essential new strategies for interconnects, such as network on chip. Power dissipation in interconnects has become a substantial part of the total power dissipation. Techniques to reduce interconnect power have thus become a necessity. In this paper, we present a design methodology that gives values...
We consider the problem of event detection in wireless sensor networks (WSNs) that are large in the sense that an event affects the statistics of the observations of a small number of sensors in the vicinity of where it occurs. An event occurs at a random time at a random location in the region (called the region of interest, ROI) covered by the WSN. We consider a distance based sensing model in which...
We study the performance of greedy scheduling in multihop wireless networks where the objective is aggregate utility maximization. Following standard approaches, we consider the dual of the original optimization problem. Optimal scheduling requires selecting independent sets of maximum aggregate price, but this problem is known to be NP-hard. We propose and evaluate a simple greedy heuristic. We suggest...
In our earlier work, the authors proposed WLAN Manager (or WM) a centralised controller for QoS management of infrastructure WLANs based on the IEEE 802.11 DCF standards. The WM approach is based on queueing and scheduling packets in a device that sits between all traffic flowing between the APs and the wireline LAN, requires no changes to the AP or the STAs, and can be viewed as implementing a ldquoSplit-MACrdquo...
We study the performance of greedy scheduling in multihop wireless networks where the objective is aggregate utility maximization. Following standard approaches, we consider the dual of the original optimization problem. Optimal scheduling requires selecting independent sets of maximum aggregate price, but this problem is known to be NP-hard. We propose and evaluate a simple greedy heuristic. Analytical...
In this paper, we study the Foschini Miljanic algorithm, which was originally proposed in a static channel environment. We investigate the algorithm in a random channel environment, study its convergence properties and apply the Gerschgorin theorem to derive sufficient conditions for the convergence of the algorithm. We apply the Foschini and Miljanic algorithm to cellular networks and derive sufficient...
We develop several hardware and software simulation blocks for the TinyOS-2 (TOSSIM-T2) simulator. The choice of simulated hardware platform is the popular MICA2 mote. While the hardware simulation elements comprise of radio and external flash memory, the software blocks include an environment noise model, packet delivery model and an energy estimator block for the complete system. The hardware radio...
In this paper, we propose a new security metric for measuring resilience of a symmetric key distribution scheme in wireless sensor network. A polynomial-based and a novel complete connectivity schemes are proposed and an analytical comparison, in terms of security and connectivity, between the schemes is shown. Motivated by the schemes, we derive general expressions for security and connectivity....
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