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The IC presented in this paper is a highly integrated low-power RF transceiver for wireless sensor networks (WSN) compliant with the IEEE 802.15.4 2.4GHz WPAN standard. It contains a radio controller with sleep timer and can perform higher-level MAC functions such as beacon detection and network timing synchronisation autonomously, thereby enabling significant power savings in the overall system....
We propose QUEST (QUality ESTimation), a new method that accurately estimates IEEE 802.11 wireless link quality with no in-band signaling overhead. Existing link quality estimation methods either are based on hello exchanges by fixing or varying transmission rates or rely on the history (e.g., delivery ratio) of previously sent data packets in a per-rate/-neighbor manner. QUEST on the other hand,...
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...
Three applications in wireless networks where model-free stochastic learning is applicable, are discussed. The learning based optimization problems are formulated and simulation results are presented. Some open issues are also discussed.
In this paper, we propose a cross-layer optimization approach that exploits retransmission diversity in wireless CDMA communications. Conventionally, data packets that are not correctly detected are usually dropped. These dropped packets can be used to help data packet detection. By exploiting all the retransmitted packets, data packets can be correctly detected with higher probability. The proposed...
In this paper, the design of a compact planar bandpass filter above a defected ground plane is presented. The filter is designed as a combination of microstrip resonators and exploits the properties of a planar electromagnetic bandgap (EBG) structure patterned unto the ground plane of the printed circuit board material to provide a very wide stopband of up to 5 times the fundamental frequency. The...
Todaypsilas access network is migrating towards broadband IP, fixed/mobile convergence and service convergence. Thus, the next generation access network (NGAN) requires a converged optical/wireless access network infrastructure, other than the existing architecture that connect to the cellular, broadband wireless, and optical access networks separately, which complicate the network and increase the...
In this paper, we evaluate network performance of non-acknowledged packet transfer in relatively large IEEE 802.15.4 network. Network under consideration contains six interconnected IEEE 802.15.4 beacon enabled network clusters in triangular topology using slave-slave (SS) bridges with CSMA-CA access. We investigate the interactions among local nodes, local bridges and remote bridges. Simulation results...
This paper addresses adaptive channel estimation for time-varying mobile wireless channels with nonstationary statistics. We presents a reduced complexity adaptive channel estimator based on a set membership filtering approach known as the Optimal Bounding Ellipsoid (OBE) algorithm. To exploit time and frequency domain correlation properties of the channel in an efficient low-complexity way, we allow...
A high intercept points, cost-effective, and power-efficient switching FET double balanced mixer (DBM) is reported. The Switching FET DBM demonstrated in this work offers input intercept points (IIP3) and conversion loss typically 44 dBm and 8.5 dB respectively with 15 dBm LO power for the frequency band (RF: 900-2150 MHz, LO: 850-1950 MHz, IF: 50-200 MHz). The measured interport isolation is typically...
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