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This paper shows a Self-organizing networks (SON) algorithm for interference coordination in downlink Orthogonal Frequency-Division Multiple Access (OFDMA) networks. A distributed algorithm is introduced with a proof of convergence for a static user population. The algorithm uses closed-form formulas for the transmit powers update, and is therefore computationally light. The proposed algorithm is...
In OFDMA-based Cognitive Radio (CR) systems, how to deal with the time-varying nature of avaliliable spectrum resources has become a hotspot and challenging problem in resource allocation. Traditional resource allocation algorithm can not guarantee proportional rates among non-real-time CR user (CRU) because the number of available subchannels is smaller than the number of CRUs in some OFDM symbol...
We consider the allocation of spectral and power resources every subframe (1~ms) on the uplink of the Long Term Evolution (LTE) wideband orthogonal frequency division multiple access (OFDMA) cellular network. System bandwidth is divided into multiple sub-bands. The fractional power control to manage interference is allowed to be a function of the sub-band. Moreover, the channel gains from the base-station...
The performance of an OFDM system can be improved by performing per-subcarrier antenna selection, which facilitates the exploitation of frequency and spatial diversity in the wireless channel. In this paper, we extend the concept of per-subcarrier antenna selection to a multiuser cognitive radio environment and present a practical subcarrier and antenna selection algorithm that exploits the multiuser,...
In this paper, we maximize the throughput of a cognitive radio (CR) network with respect to the frame length when quickest sensing is used. The amount of interference to the primary network, measured by the probability of collision with primary users (PUs), is constrained below a certain maximum. The corresponding problem when CRs use block sensing is also solved, assuming that collision with PUs...
Mesh Wireless Local Area Network (WLAN) is a promising access network to enhance channels utilization, extend access coverage with simple and cheap network components. Power management affects mesh WLAN network coverage, topology, throughput, traffic routing and end to end delay. In this paper, power management problem is formulated to show its impact on mesh WLAN network throughput. Then this formulation...
The main objectives of a self-organizing network (SON) technology are autonomous network deployment, network performance optimization and real-time adaptation to environmental changes. There are three functionalities in SON, such as self-configuration, self-optimization and self-healing. In this paper, we focus on the self-healing issue with respect to abrupt network faults. In order to solve this...
An optimal multichannel spectrum sensing framework which searches for multiple secondary transmission opportunities over a number of narrowband channels is presented. The framework, referred to as sequential multichannel joint detection, enhances the secondary network performance while respecting the primary network integrity and keeping the interference limited. Considering a sequential periodic...
We consider one of the latest feature included in the Release 9 of the GSM/EDGE standard: the Orthogonal Sub Channel (OSC) transmission scheme. OSC aims at doubling the cell capacity by multiplexing two co-cell users on the same radio resource. In this work we deal with the challenge of finding the optimum pairing strategy among co-cell OSC users exploiting the Adaptive QPSK (AQPSK) modulation in...
We consider prefiltering for a single-carrier transmission over frequency-selective channels, where reduced-state trellis-based equalization is employed at the receiver, such as delayed decision-feedback sequence estimation (DDFSE) or reduced-state sequence estimation (RSSE). While previously proposed prefiltering schemes are based on the optimum filters of decision-feedback equalization (DFE), the...
We consider a multipoint-to-multipoint cognitive network wherein the communications from L sources to their designated destinations are carried out through the use of K relays in a dual-hop amplify-and-forward cooperative scheme. Aiming to maximize the worst signal-to-interference-plus-noise ratio of the L destinations, we develop a technique that jointly optimizes the sources' transmit powers and...
Coordinated multi-point (CoMP) has been selected as a key technology feature of LTE-Advanced, as it enables the exploitation of inter-cell interference in order to significantly increase spectral efficiency, especially at the cell-edge. While first field trials on CoMP schemes have delivered the proof-of-concept and shown that a moderate extent of theoretically predicated CoMP gains can indeed be...
In this paper, we formulate a joint optimization problem for resource allocation and scheduling in full-duplex orthogonal frequency division multiple access (OFDMA) relaying systems with amplify-and-forward (AF) and decode-and-forward (DF) relaying protocols. Our problem formulation takes into account heterogeneous data rate requirements for delay sensitive users. Besides, a theoretically optimal...
This paper studies the \emph{robust weighted-sum rate} optimization problem in the presence of channel uncertainty over a $K$-user Gaussian Interference Channel (GIFC), where multiple antennas are present at all transmitters and receivers. Motivated by recent results on \emph{interference alignment} that show the optimality of linear precoders and simple receivers in achieving the maximum degrees-of-freedom...
This papers considers the downlink of a wireless multicell downlink orthogonal frequency division multiple-access (OFDMA) system where neighboring base-stations (BSs) can jointly encode and transmit data signals to their users using zero-forcing (ZF) precoding in each frequency tone, but only a limited backhaul-capacity is available for each BS to share its user's data streams with the neighboring...
In this paper, we consider filter-and-forward beamforming (FF-BF) for two-way relay networks employing single-carrier transmission over frequency-selective channels. In FF-BF, the relay nodes filter the received signal using finite impulse response (FIR) or infinite impulse response (IIR) filters. For the processing at the transceivers, we investigate two different cases: (1) simple slicing without...
Interference alignment has emerged as new tool for achieving high capacity in multi-user and multi-channel wireless interference channels. Based on maximizing a degree of freedom (DOF) metric defined for asymptotic signal to noise ratio (SNR), interference alignment encounters limitations in practical applications because of limited SNR. In addition, perfect interference alignment requires strict...
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