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This paper presents the design, implementation and performance evaluation of a hybrid MAC protocol, called Z-MAC, for wireless sensor networks that combines the strengths of TDMA and CSMA while offsetting their weaknesses. Like CSMA, Z-MAC achieves high channel utilization and low-latency under low contention and like TDMA, achieves high channel utilization(More)
This paper presents a distributed implementation of RAND, a randomized time slot scheduling algorithm, called DRAND. DRAND runs in <i>O</i>(&#948;) time and message complexity where &#948; is the maximum size of a two-hop neighborhood in a wire-less network while message complexity remains <i>O</i>(&#948;), assuming that message delays can be bounded by an(More)
Congestion control in wireless multi-hop networks is challenging and complicated because of two reasons. First, interference is ubiquitous and causes loss in the shared medium. Second, wireless multihop networks are characterized by the use of diverse and dynamically changing routing paths. Traditional end point based congestion control protocols are(More)
A randomized dining philosophers algorithm is presented for a realistic semi-synchronous model where message delays vary within an unknown bound, and clocks may run at a different speed without any synchronization. In order to predict the unknown bounds, the algorithm employs a simple network delay measurement technique. The algorithm has an expected(More)
Limited resources and time-varying nature of wireless ad hoc networks demand optimized use of resources across layers. Cross-layer optimization (CLO) for wireless networks, an approach that coordinates protocol behaviors at different layers with a goal to maximize a utility function, has received considerable attention lately. However, most existing work(More)
In this demo, we showcase DiffQ - a congestion control protocol inspired by theoretical cross-layer optimization approaches. DiffQ can support congestion control for network flows that use either single-path or opportunistic multi-path routing. Our demo will focus on the performance in single-path routing environments, where contemporary end-point(More)
Topology control is an important feature for energy saving, and many topology control protocols have been proposed. Yet, little work has been done on quantitatively measuring practical performance gains that topology control achieves in a real sensor network. This is because many existing protocols either are too complex or make too impractical assumptions(More)
Space Division Multiple Access (SDMA) based Medium Access Control (MAC) protocols have been proposed to enable concurrent communications and improve link throughput in Multi-Input Multi-Output (MIMO) Ad Hoc networks. For the most part, the works appearing in the literature make idealized and simplifying assumptions about the underlying physical layer as(More)
In this paper, we propose TBB-MAC, an enhancement for medium access control (MAC) protocol based on the token bus in wireless sensor networks (WSNs). In this type of networks, sensors are spatially correlated and they often sense and collect the information and send it to the sink. In this paper, we design an innovative contention-based MAC protocol to(More)