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One major topic of research into SON technology is the coordination of SON use cases. Network operators expect a coordinated handling of the parameter and configuration changes submitted to the operating network by closed-loop SON use case implementations. Beside a published conceptual framework, SON coordination has already been treated in the literature, especially regarding the mobility load balancing...
Energy-based sensing (EBS) has been a topic of strong research in the last years due to its importance to Cognitive Radios (CRs). While EBS has been used in several works, different parameterizations have been adopted. In this work we compare different parameterization criteria to determine the decision threshold to the energy detector. We compare their performance through simulations by characterizing...
We address the use of single parity check product codes (SPCPC) for erasure recovery in opportunistic spectrum access schemes, where erasures are packets lost during a collision with the primary user (PU) due to sensing impairments (non detection). Our main motivation in using SPCPC is their low decoding complexity. We derive an analytical performance bound for these product codes when the PU's activity...
This paper presents a game theoretic solution for end-to-end flow allocation with joint channel and power assignment in multihop cognitive radio networks under the physical interference model. The objective is to find a distributed solution that maximizes the network utility with limited information. We consider two different criteria to define this network utility: the number of flows that can be...
In this paper, a DTV interference test was performed in order to measure the affected ranges of the DTV service that result from the operating of a narrowband system as a DTV White Space Service under severe environmental conditions. The DTV coexistence testing was performed in order to review the degree of DTV signal degradation depending on the bandwidth of the secondary users. For this, the criteria...
This article addresses energy detection for spectrum sensing of M-ary quadrature amplitude modulation (QAM) systems. Analytical expressions are developed for the average probability of detection in these systems. The analytical results are validated by numerical simulations and comparisons with different approximated approaches found in the literature are made. We see that the approximations usually...
An efficient beam updating method for multi-user multiple-input multiple-output (MU-MIMO) downlink channels is considered in time-varying channels. Previously, the beam design method based on signal-to-leakage-plus-noise ratio (SLNR) was introduced with given channel matrices. The solution maximizing SLNR is obtained by a generalized eigen-decomposition with a pair of covariance matrices of desired...
In this paper, a novel resource allocation method is proposed for a multiuser MIMO SC-FDMA communication system. The proposed method, well-suited for the uplink scenario of the LTE Advanced standard, allocates the frequency spectrum among its users with the goal of maximizing the system's overall throughput. To achieve this goal, an analytical expression of the signal to interference plus noise ratio...
We investigate the design of optimized input distributions for the two-hop Gaussian relay channel under an average power constraint. In our study, the relay is confined to implement an estimate-and-forward strategy. We demonstrate that the rate achievable by an optimized discrete input distribution can significantly outperform that achievable by a Gaussian codebook. The lower bound obtained by the...
Characteristic of receiver output SNR associated with Source-to-Relay-to-Destination link for Amplify and forward relaying systems is studied and theoretical expressions for probability density function and cumulative distribution function are derived. Thereby, closed-form solution for outage probability of the system is derived. The analysis is then extended to a scenario where the destination combines...
In FD-AWGN relay channel, the source sends the superposition of many capacity-achieving codewords. The relay decodes them using successive interference cancellation (SIC) and sends the superposition of the same codewords multiplied by random dither sequences and with a new power distribution among the codewords. The destination node decodes all code-words by removing the dithering and then applying...
Cooperative systems are being widely investigated and error probability expressions for various network configurations have been obtained. Even though analytical models are accurate, they often lack tractability and do not shed much light on the interplay between channel conditions, network parameters and transceiver characteristics. This paper exploits a recently introduced technique, which uses...
Femtocells and WiFi have been considered as viable concepts in cellular networks to increase overall system capacity. Critical functionalities for the successful integration of such technologies in macro-cellular topologies are related to radio resource allocation and interference management techniques that must ensure seamless intra-cell and inter-cell interoperation among macro- and femto users,...
The separated restricted two-way relay channel (TWRC) has two sources that are outside of radio range and must communicate with the help of a relay. The relay is limited to perform memoryless operations on its received symbols to compute its channel input. Relay functions optimizing the achievable sum rate for both sources are investigated for binary antipodal signaling and pulse amplitude modulation...
In this paper, four transmit beamforming (BF) techniques are selected and compared to realize inter-operator spectrum sharing, which is a promising solution for the spectrum shortage problem. The BF techniques include two game-theoretic (GT) algorithms, zero-forcing (ZF) and minimum mean square error (MMSE). After a brief description of the BF techniques in a multiple-input single-output (MISO) system,...
Maximizing the Radio Frequency IDentification (RFID) performance is one of the main challenges for a wide variety of applications, where the overall throughput can be significantly affected by undesired Tag-Tag collision events. The UHF EPC Class-1 Generation-2 (Gen2) protocol only specifies algorithms to avoid the collisions but makes no provision for their resolution. In this paper, performance...
In this paper, we propose to evaluate the gain of multiple resource block (RB) allocation to user equipments (UEs) on the LTE uplink. Our multiple RB allocation strategy aims at achieving high cell's capacity and is compliant with SC-FDMA specificities i.e. UE limited transmission power and same modulation and coding scheme (MCS) for all allocated RBs to a given UE. The main implication of these constraints...
Femtocells are low power access points that can be deployed by the consumer indoors to alleviate cellular coverage problems, offload traffic from the cellular network and boost user data rates. To enable the widespread of femtocells coexisting with macrocells, smart interference management schemes are required. Interference management by frequency allocation is still a big challenge in hybrid macro/femto...
The Device-to-Device (D2D) communication can increase data rates and resource utilization in cellular networks. However, the direct application of the D2D communication can cause harmful interference to the cellular network. Therein, power control algorithms become essential tools to keep interference controlled and to ensure improved system performance. In this paper, we study two power control strategies...
The usage of relays and OFDM can improve the performance of wireless systems in terms of data rates, coverage and reliability. In this paper we study joint subcarrier matching and power allocation for two-hop relay systems with the purpose of maximizing the total spectral efficiency. The problem is formulated as a mixed integer (binary) problem, but due to its complexity, the problem is separated...
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