scholarly journals Cross-Layer Throughput Optimization in Cognitive Radio Networks with SINR Constraints

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Miao Ma ◽  
Danny H. K. Tsang
Keyword(s):  
Cognitive Radio ◽  
Mathematical Formulation ◽  
Heuristic Method ◽  
Global Optimum ◽  
Mixed Integer ◽  
Cross Layer ◽  
Throughput Optimization ◽  
Radio Interference ◽  
Secondary Users ◽  
Optimization Simulation

Recently, there have been some research works in the design of cross-layer protocols for cognitive radio (CR) networks, where the Protocol Model is used to model the radio interference. In this paper we consider a multihop multi-channel CR network. We use a more realisticSignal-to-Interference-plus-Noise Ratio (SINR)model for radio interference and study the following cross-layer throughput optimization problem: (1) Given a set of secondary users with random but fixed location, and a set of traffic flows, what is the max-min achievable throughput? (2) To achieve the optimum, how to choose the set of active links, how to assign the channels to each active link, and how to route the flows? To the end, we present a formal mathematical formulation with the objective of maximizing the minimum end-to-end flow throughput. Since the formulation is in the forms ofmixed integer nonlinear programming (MINLP), which is generally a hard problem, we develop a heuristic method by solving a relaxation of the original problem, followed by rounding and simple local optimization. Simulation results show that the heuristic approach performs very well, that is, the solutions obtained by the heuristic are very close to the global optimum obtained via LINGO.

scholarly journals Joint Subchannel Pairing and Power Control for Cognitive Radio Networks with Amplify-and-Forward Relaying

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Yanyan Shen ◽  
Shuqiang Wang ◽  
Zhiming Wei
Keyword(s):  
Cognitive Radio ◽  
Power Allocation ◽  
Cognitive Radio Networks ◽  
Radio Networks ◽  
Cooperative Transmission ◽  
Mixed Integer ◽  
Amplify And Forward ◽  
Secondary Users ◽  
Power Constraints ◽  
Sum Rate

Dynamic spectrum sharing has drawn intensive attention in cognitive radio networks. The secondary users are allowed to use the available spectrum to transmit data if the interference to the primary users is maintained at a low level. Cooperative transmission for secondary users can reduce the transmission power and thus improve the performance further. We study the joint subchannel pairing and power allocation problem in relay-based cognitive radio networks. The objective is to maximize the sum rate of the secondary user that is helped by an amplify-and-forward relay. The individual power constraints at the source and the relay, the subchannel pairing constraints, and the interference power constraints are considered. The problem under consideration is formulated as a mixed integer programming problem. By the dual decomposition method, a joint optimal subchannel pairing and power allocation algorithm is proposed. To reduce the computational complexity, two suboptimal algorithms are developed. Simulations have been conducted to verify the performance of the proposed algorithms in terms of sum rate and average running time under different conditions.

scholarly journals Exact minimization of the energy losses and the CO2 emissions in isolated DC distribution networks using PV sources

DYNA ◽  
2021 ◽  
Vol 88 (217) ◽  
pp. 178-184
Author(s):  
Alexander Molina ◽  
Oscar Danilo Montoya ◽  
Walter Gil-González
Keyword(s):  
Mathematical Formulation ◽  
Main Idea ◽  
Distribution Networks ◽  
Global Optimum ◽  
Mixed Integer ◽  
Energy Losses ◽  
Electrical Networks ◽  
Convex Model ◽  
Daily Energy ◽  
Minlp Model

This paper addresses the optimal location and sizing of photovoltaic (PV) sources in isolated direct current (DC) electrical networks, considering time-varying load and renewable generation curves. The mathematical formulation of this problem corresponds to mixed-integer nonlinear programming (MINLP), which is reformulated via mixed-integer convex optimization: This ensures the global optimum solving the resulting optimization model via branch & bound and interior-point methods. The main idea of including PV sources in the DC grid is to minimize the daily energy losses and greenhouse emissions produced by diesel generators in isolated areas. The GAMS package is employed to solve the MINLP model, using mixed and integer variables; also, the CVX and MOSEK solvers are used to obtain solutions from the proposed mixed-integer convex model in the MATLAB. Numerical results demonstrate important reductions in the daily energy losses and the harmful gas emissions when PV sources are optimally integrated into DC grid.

Cross-Layer Design in Cognitive Radio Systems

2013 ◽  
pp. 89-110
Author(s):  
Krishna Nehra ◽  
Mohammad Shikh-Bahaei
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sharing ◽  
Spectrum Management ◽  
Cross Layer ◽  
Cross Layer Design ◽  
Secondary Users ◽  
Network Layers ◽  
Cognitive Radio Systems ◽  
Radio Systems ◽  
Exhaustive Study

The main functionalities of a cognitive radio system, to ensure efficient operation of the primary users without harmful intervention from the secondary users and to simultaneously satisfy the requirements of the secondary users, are spectrum sensing, spectrum management, spectrum mobility, and spectrum management. These functions involve more than one layer of protocol stack rather than being performed at a single layer. This chapter briefly revisits these functions from the perspective of classification of the roles of different communication network layers in carrying out these functions. An exhaustive study is then presented of the key properties of cross-layer design applications in cognitive radio systems by taking examples from the existing literature and highlighting some open challenges and new opportunities. A cross-layer design example for interference-limited spectrum sharing systems is discussed in detail, which considers the parameters from the Physical Layer (PHY) and the Data Link Layer (DLL) in order to maximize the overall spectral efficiency of the Secondary User (SU). The numerical results show that the secondary link of spectrum sharing systems combining ARQ with adaptive modulation and coding achieves significant gain in throughput depending on the maximum number of retransmissions.

scholarly journals CROSS LAYER BASED THROUGHPUT OPTIMIZATION IN COGNITIVE RADIO NETWORKS WITH EFFECTIVE CHANNEL SENSING SCHEMES

2010 ◽  
Vol 01 (02) ◽  
pp. 98-106
Author(s):  
Manimekalai T. ◽  
◽  
Meenakshi M. ◽  
Princy Dinal D. ◽  
Koteeshwari R.S. ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Radio Networks ◽  
Cross Layer ◽  
Throughput Optimization ◽  
Channel Sensing ◽  
Effective Channel

scholarly journals An SETM Algorithm for Combating SSDF Attack in Cognitive Radio Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
S. Tephillah ◽  
J. Martin Leo Manickam
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Trust Management ◽  
Cooperative Spectrum Sensing ◽  
Radio Networks ◽  
Second Phase ◽  
Common Channel ◽  
Secondary Users ◽  
Management Algorithm ◽  
Different Types

Security is a pending challenge in cooperative spectrum sensing (CSS) as it employs a common channel and a controller. Spectrum sensing data falsification (SSDF) attacks are challenging as different types of attackers use them. To address this issue, the sifting and evaluation trust management algorithm (SETM) is proposed. The necessity of computing the trust for all the secondary users (SUs) is eliminated based on the use of the first phase of the algorithm. The second phase is executed to differentiate the random attacker and the genuine SUs. This reduces the computation and overhead costs. Simulations and complexity analyses have been performed to prove the efficiency and appropriateness of the proposed algorithm for combating SSDF attacks.

Operating point selection for primary and secondary users in cognitive radio networks

2009 ◽  
Vol 53 (8) ◽  
pp. 1158-1170 ◽  
Author(s):  
Xavier Gelabert ◽  
Ian F. Akyildiz ◽  
Oriol Sallent ◽  
Ramon Agustí
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Radio Networks ◽  
Operating Point ◽  
Point Selection ◽  
Secondary Users ◽  
Selection For ◽  
Primary And Secondary Users
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