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In this paper, a channel estimation method and a detection technique for multibeam communications systems are developed. The channel estimation uses the output of a beam former to determinate the channels parameters for each active user in the system. The detection technique assures the determination of QPSK symbols after compensation of channel effects. An antenna array is considered at the receiver...
The estimation of the position of an emitting source is an important aspect of emerging cognitive radio systems. We readdress the known problem of estimating the Direction-of-Arrival (DOA) of an emitting source via passive radio means, namely an antenna array. The challenges in the considered scenarios are (a) time-varying, terrestrial multipath propagation with medium-to-low SNR and (b) very short...
When multi-user multiple-input multiple-output (MU-MIMO) is applied to predominantly line-of-sight (LoS) environments, such as in the case of fixed wireless access in rural areas where a central access point (AP) equipped with an antenna array with NAP antenna elements serves NUT user terminals (UTs) each equipped with a single antenna, the problem of ill-conditioned channels arises. This paper investigates...
In order to solve the inevitable data collision in competitive datalink random access of wireless sensors networking, this paper provides a blind property restoral maximum likelihood (ML) approach for demodulating multiple co-channel digital signals received synchronously at an antenna array. The finite alphabet property of digital signal combining with ML is analyzed, the array response and symbol...
In this paper, a new array signal processing technique, which make use of the particle swarm optimization (PSO), is proposed. Using cross ambiguity function (CAF) calculation an optimization criteria is defined and PSO is used to find the global minimum point of the obtained cost function. Developed particle swarm optimization - direction finding technique (PSO-DF) estimates time delay, Doppler shift,...
A new MIMO channel model based on angular-domain, double-directional channel model is proposed. Angular domain is a more appropriate coordinate to describe the MIMO channel, since the incoming rays and outgoing rays appear in clusters in the real world. This model is developed based on linear space and sampling theory and is applicable to any practical antenna geometry and includes the actual radiation...
This paper presents an ultra-wideband (UWB) double-directional channel sounding technique using transformation between time domain (TD) and frequency domain (FD) signals. We proposed the time-of-arrival (TOA), angle-of- arrival (AOA) estimation algorithm and angle-of-departure (AOD) with some modifications of our previous work. There were four main advantages of the proposed estimation technique as...
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