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Estimating the number of sources impinging on an array of sensors is a well known and well investigated problem. Based on the rotational invariance property between two identical subarrays, using the Lanczos algorithm to fast compute the analysis filterbank of multi-stage wiener filter, a novel method for fast estimating the number of wideband sources is proposed in this paper. Unlike the traditional...
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.
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H) which is required to operate under high mobility conditions resulting in significant Inter-Carrier Interference (ICI). Under these conditions, the conventional one-tap per subcarrier channel estimation and equalization is suboptimal since it does not account for ICI...
In this paper, we consider a new channel probing scheme for opportunistic scheduling in the uplink of orthogonal frequency division multiplexing (OFDM)-based wireless systems. To reduce signaling overhead for the probing, we consider a two-step channel probing process; called pre-probing and mainprobing. Good subchannels are first estimated through the pre-probing process using a probing signal transmitted...
In this paper, we propose an adaptive pacing scheme at the link layer for IEEE 802.11 based multihop wireless networks. Our objective is to improve the performance of higher layer protocols without any modifications to them. Our adaptive pacing scheme estimates the four-hop transmission delay in the network path without incurring any additional overheads, and accordingly paces the packets to reduce...
In this paper, we propose a cognitive radio-based multi-user resource allocation framework for mobile ad hoc networks using multi-carrier DS CDMA modulation over a frequency-selective fading channel. In particular, given pre-existing communications in the spectrum where the system is operating, in addition to potential narrow-band interference, a channel sensing and estimation mechanism is provided...
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