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With high data rate and mobility support wireless networks are becoming an integral part of the ubiquitous broadband access. Appropriate dimensioning of the wireless access networks is essential to satisfy users' Quality of Service (QoS) requirements. Once the network is dimensioned, dynamic variations in traffic or population distribution can affect the capability of the network to deliver the agreed...
We derive capacity upper and lower bounds for a multi-user multiple-input multiple-output (MU-MIMO) system in a two dimensional line-of-sight environment where the central node is equipped with a uniform circular array and the remote nodes are distributed from the central node at an equal distance and equal angular separation. We first show that this channel can be represented by a circulant matrix...
Small cells with wireless backhaul are promising, whereas challenges of severe overlapping coverage and strong interference are yet to be addressed. Coordinating small cells could resolve the challenges; however, existing multicell coordinated beamforming techniques involve high cost of communication overhead, synchronization and backhaul. Such problems may deteriorate in practical cellular applications,...
Multi-user multiple-input multiple-output (MU-MIMO) has a potential to realize cost effective high data rate internet access to the homes in rural areas. We propose the novel Ngara Access system where the central access point (AP) is equipped with a uniform circular array (UCA) installed on a high tower while each UT is equipped with a directional antenna free of clutter, providing predominantly line-of-sight...
In this paper, we present a novel user selection scheme for the broadcast channel (BC) using zero-forcing (ZF) precoding with optimal power control. Our scheme is based on a threshold that sets a minimum acceptable sum-rate. In order to design the threshold, we develop a new approximation of the sum-rate and derive simple design rules for the threshold with complexity constraints. We also extend the...
In wireless dual-hop decode-and-forward (DF) relaying networks, multiple relay stations (RS) and users construct a DF broadcast channel (DFBC). Due to unpredictable decoding failure, scheduling in the DFBC should depend on not only channel qualities but also the availability of error-free data at individual RSs. Based on the reception qualities of RSs and channel quality information (CQI), we propose...
Multiple amplify-and-forward (AF) relays with receive diversity is analyzed over unbalanced hops with independent but not necessarily identically distributed Rayleigh fading. Exact closed-form expressions are derived for the moment generating function of the end-to-end signal-to-noise ratio (SNR) at the destination. Our analysis apply to arbitrary numbers of relays and arbitrary numbers of antennas...
This paper considers the performance of the multiuser multi-antenna downlink where NT base station antennas transmit to K non-collocated, single antenna users over correlated channels. A practical and near-capacity multi-user technique called vector perturbation precoding (VPP) is considered. For these scenarios, we derive a lower bound to the average energy of the precoded vector. We use this to...
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