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For a single user with multiple receive antennas, co-antenna interference can be the dominant source of impairment in a Spatial Multiplex Orthogonal Frequency Division Multiple Access (SM-OFDMA) system, particularly when correlation exists between spatial sub-channels. By exploiting knowledge of the channel response and combining it with Dynamic Sub- Carrier Allocation (DSA), the algorithm proposed...
We consider the problem of a transmitter transmitting to its receiver over a wireless link subject to jamming and develop two online power control algorithms for maximizing wireless link quality (transmission rate). We assume that the transmitter transmits and the jammer interferes over a period of M time slots. The impact of the jammer is to deteriorate the quality of the wireless channel during...
Implementing dynamic spectrum assignment and access technologies in heterogeneous wireless networks may lead to considerable improvement in spectrum usage and quality of service. In this paper we evaluate the performance of SINR-based dynamic spectrum assignment and access algorithms using simulation. We compare network capacity values gained using these two algorithms with the one gained using SINR-based...
In this paper, we present an enhancement to our previously proposed algorithm, SOR, for the minimum energy broadcasting problem in wireless sensor ad hoc networks. We implement the enhanced algorithm, PSOR (Partitioning- based SOR), and compare its solution quality with other algorithms in the literature: BIP, OMEGa, SOR, and EWMA. The enhancement comes from the diversification of solution space by...
We consider the problem of exchanging packets from the individual queues at multiple wireless terminals with the assistance of a single relay node. In an earlier paper, we studied this for a backlogged traffic model, where each node always had packets to transmit. Here, we consider stochastically varying packet traffic and compare the stable operation under plain routing, and digital and analog network...
Opportunistic routing (OR) schemes, such as ExOR, have been shown to provide significant throughput gains over traditional best-path routing schemes for wireless networks. Though the performance of OR schemes depend on the bit-rate, they currently use a fixed rate for transmitting packets. While several schemes have been proposed for selecting bit-rate for unicast transmission to a single receiver,...
Network coding is known to improve throughput by mixing information from different flows and conveying more information in each transmission. Recently some proposals have demonstrated the benefits of applying network coding to wireless networks with broadcast transmissions. It is expected that the opportunities for coding and the corresponding gains depend on the bit-rate chosen for determining routes...
In this paper, a predictive model for compression of mosaic image with Bayer pattern is proposed. It consists of TFNN neural network predictor and adaptive correction part based on context. As in JPEG-LS, the adaptive part of the predictor is context-based and it is used to ldquocancelrdquo the integer part of the offset due to the TFNN predictor. In the meantime, we propose a context quantization...
This paper investigates effects of pilot assisted channel estimation on dynamic resource allocation in a multiuser orthogonal frequency division multiplexing (OFDM) system. The channel estimation is done in each OFDM symbol through least-squared error (LSE) or minimum mean-squared error (MMSE) algorithm. The performance of each of these algorithms is evaluated through computer simulations. The maximal...
Wireless sensor networks consist of a large number sensors spread across a given geographical area. Each sensor has its own communication capability as well as certain level of intelligence for signal processing and networking. As the sensor nodes are densely populated, communication range requirement for these nodes is smaller. After signal detection, a number of sensor nodes communicate over the...
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