WSEAS Transactions on Communications
Print ISSN: 1109-2742
E-ISSN: 2224-2864
Volume 15, 2016
Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of WSEAS Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.
Volume 15, 2016
Title of the Paper: New Transceiver Scheme for FDMA Systems Based on Discrete Sine Transform
Authors: Bashar Ali Farea, Nor Shahida Mohd Shah
Abstract: In this paper, the discrete sine transform (DST) as an orthogonal basis is used rather than the conventional discrete Fourier transform (DFT) to implement the orthogonal frequency division multiple access (OFDMA) system. The obtained system is called a DST-OFDMA system. The performance of the proposed DST-OFDMA system is studied and compared with the conventional discrete Fourier transform (DFT)-based OFDMA (DFT-OFDMA) system. The peak power problem in the proposed DST-OFDMA and in the recent DST-based SC-FDMA (DST-SC-FDMA) is also investigated and compared for different subcarriers mapping schemes and modulation formats. The impact of the radio resources allocation is also investigated at different roll-off factors. Simulation results show the improvement in the bit error rate (BER) of the proposed system over the conventional system by about 9 dB and 6 dB for interleaved and localized subcarriers mapping, respectively with quadrature phase shift keying (QPSK).
Keywords: DST, OFDMA, SC-FDMA, DFT, PAPR, BER
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #41, pp. 369-377
Title of the Paper: Partial Penalty Method for Flow Optimization in Wireless Networks
Authors: I. V. Konnov, O. A. Kashina, E. Laitinen
Abstract: We consider a general problem of optimal assignment of users to providers of wireless telecommunication networks, which minimizes the total expenses and has certain resource allocation restrictions. We show that it can be formulated as an extended transportation problem. Due to variability of demand and inexactness of data we suggest to solve this problem by a suitable penalty method. We consider both full and partial versions of this method and show that the latter has certain preferences. The computational experiments confirm these conclusions.
Keywords: Resource allocation, wireless networks, assignment of users, transportation problem, partial penalty method
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #40, pp. 363-368
Title of the Paper: Establishment and Optimization of Distribution Network Operation Mode Considering Operation and Grid Risk
Authors: Kang Wei, He Chunguang, Zhou Mingyu ,Cai Jiaming, An Jiakun, Xie Xiaolin, Liu Yong
Abstract: Traditional establishment and optimization method of distribution network operation mode doesn’t take risk factors into consideration. In order to make the distribution network operate in the optimal operation mode, this paper proposes an establishment and optimization method of distribution network operation mode considering operation and grid risk. The proposed optimization model is a multi-objective nonlinear optimization model, which brings operation risk and grid risk of distribution network into the operation mode optimization. Besides, the proposed multi-objective optimization model is simplified as a single objective optimization model using weights. The calculation results of a numerical example proves the validity of the proposed optimization method of distribution network operation mode. In addition, it can meet users’ demand for operation risk and grid risk.
Keywords: distribution network, operation mode, operation risk, grid risk
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #39, pp. 353-362
Title of the Paper: Level Crossing Rate of Macrodiversity with Three Microdiversities in the Presence of Long Term Fading and Mixed Short Term Fading
Authors: Dragana Krstić, Radmila Gerov, Vladeta Milenković, Djoko Bandjur, Zoran Popović, Mihajlo Stefanović
Abstract: In this paper, macrodiversity (MAD) reception with MAD selection combining (SC) receiver and three microdiversity (MID) maximal ratio combining (MRC) receivers is analyzed. Received signal in the first MID MRC receiver experiences Gamma long term fading and Nakagami-m short term fading, received signal in the second MID MRC receiver experiences Gamma long term fading and Rician short term fading and received signal in the third MID MRC receiver experiences Gamma long term fading and κ-μ short term fading. Level crossing rates of signals at outputs of MID receivers are calculated and by using these expressions, the level crossing rate (LCR) of MAD SC receiver output signal is evaluated. The influence of Rician factor of κ-μ short term fading, Rician factor of Rician short term fading, severity parameter of Nakagami-m short term fading, severity parameter of Gamma long term fading and correlation coefficient of Gamma long term fading on level crossing rate is studied and discussed.
Keywords: macrodiversity reception, microdiversity reception, Gamma fading, κ-μ short term fading, Nakagami-m short term fading, Rician fading, level crossing rate
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #38, pp. 345-352
Title of the Paper: Minimizing of Transmitting Antenna’s Reflections when Performing EMI Tests
Authors: Martin Pospisilik, Milan Adamek, Petr Neumann
Abstract: Within the framework of the electromagnetic compatibility tests performed on common communication systems, one of the most common tests is the immunity test according to the standard EN 61000-4-3. This test is usually processed inside a shielded anechoic chamber, meeting the appropriate standards. As the levels of the generated fields can be high and the output power of the transmitting amplifiers cannot be infinite, it is necessary to achieve a good performance of the transmitting antenna. The authors of this paper present the experiment performed in the anechoic chamber Frankonia SAC3 plus that shows that the height of the antenna above the chamber's floor affects the antenna's performance. Especially in vertical polarization, the performance of the antenna can be improved by slight adjustment of its height.
Keywords: Communication Systems EMC, Immunity Test, Transmitting Antenna, Output Power, Standing Waves Ratio, Shielded Chamber
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #37, pp. 337-344
Title of the Paper: Numerical Simulation and Traffic Analysis in Carrier Voice Networks
Authors: Marius Popescu, Andrei Gabor, Antoanela Naaji
Abstract: Performing traffic and voice transmission quality analysis is sometimes required in carrier voice networks due to conflicts appear between operators. One of the reasons of conflicts is, in many cases, the incomplete national regulations in the field of telecommunications. In such cases, juridical expertise should be carried out in the similar conditions as the real environment, but in almost all the situations the specific equipment is not available anymore. In order to highlight certain technical aspects and compensate for the lack of equipment, a software that simulates equipment and processes in telecommunication networks are necessary. The paper presents a simulation process of interconnection between operators, realized at the beginning of 2016, for establishing the quality parameter for a real case from 2004. The simulation is based on an interface represented by Voice Gateway, and through various settings on a dial plan, which can establish a real operation. Voice Gateway configuration is particularly complex and can go up to transforming the simulation into a gateway configuration tutorial. Finally, traffic trends are studied over a period of time, analyzing the conflicts started between the two telecommunications operators regarding traffic and quality of services.
Keywords: ID change, simulation, traffic, voice quality, IP networks, VoIP
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #36, pp. 323-336
Title of the Paper: Performance Analysis in a PAM-4 Fiber Transmission IM-DD with Pre-Compensation Filter
Authors: Alessandro Vigano, Maurizio Magarini, Arnaldo Spalvieri
Abstract: In this paper we study the performance of 4-ary pulse amplitude modulation (PAM-4) transmission using intensity modulation with direct detection (IM-DD) on a fiber link of 80 km. The system uses a pre-compensation filter to take care of the chromatic dispersion. Specifically, it is studied the effect of the difference between nominal chromatic dispersion used in the pre-compensation filter and the actual value of the chromatic dispersion introduced by the fiber. This is because the actual length of the fiber can be different from the designed one and, also, because the dispersion parameter can vary because of changing in refractive index of the fiber that can be caused by the temperature variation. Simulation results obtained by means of Monte Carlo simulations are used to show the sensitivity of bit error rate performance to the mismatch between nominal and actual value of the chromatic dispersion.
Keywords: Pulse amplitude modulation (PAM), intensity modulation, direct detection, non-coherent demodulation, chromatic dispersion
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #35, pp. 317-322
Title of the Paper: Application of Market Equilibrium Models to Optimal Resource Allocation in Telecommunication Networks
Authors: Igor Konnov, Aleksey Kashuba, Erkki Laitinen
Abstract: We consider several problems of optimal resource allocation in telecommunication networks and show that they can be formulated as market equilibrium models. This approach enables us to create simple and efficient solution methods. Next, we consider such a resource allocation problem for a provider of a wireless communication network divided into zones (clusters). The network manager aims to distribute some homogeneous resource (bandwidth) among users of several zones in order to maximize the total network profit, which takes into account payments from users and implementation costs. As a result, we obtain a convex optimization problem involving capacity and balance constraints. By using the dual Lagrangian method with respect to the capacity constraint, we reduce the initial problem to a suitable one-dimensional problem, so that calculation of its cost function value leads to independent solution of zonal problems, treated as two-side market equilibrium models with one trader. We show that solution of each zonal problem can be found exactly by a simple arrangement type algorithm even in the case where the trader price is not fixed. Besides, we suggest ways to adjust the basic problem to the case of moving nodes. Some results of computational experiments confirm the applicability of the new method.
Keywords: Resource allocation, wireless networks, bandwidth, market equilibrium models, convex optimization, Lagrangian duality method, decomposition, non fixed prices
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #34, pp. 309-316
Title of the Paper: Remote Control of Devices by Means of GSM Network
Authors: Martin Pospisilik, Tomas Smekal, Milan Adamek, Petr Neumann, Tomas Dulik
Abstract: This paper describes a possibility of utilization of a GSM network for remote controlling of various appliances as house gates, heating, sunblinds etc. A project of a remote gate controller based on Arduino platform and GSM data transfers is mentioned hereby, but the purpose of utilization of the remote controller can be easily changed to another application. The main idea of the paper is based on the fact that although most remote controllers for entrance gates operate on free frequencies 433 or 868 MHz, their user's comfort is limited. On the other hand, GSM networks enable encrypted and bidirectional data transfers, allowing the user to communicate with the controlled device by means of his personal mobile pohne. Moreover, the user can be informed on any undesirable states that occured at the remote device. For example, he can be informed via his mobile phone when his house's gate is irrupted.
Keywords: GSM Network, Data transfers, Arduino, GSM Shield, Remote controlling, Gate controller
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #33, pp. 299-308
Title of the Paper: IQI Problem in Discrete Sine Transform Based FDMA Systems
Authors: Bashar Ali Farea, Nor Shahida Mohd Shah
Abstract: In this paper, in-phase and quadrature-phase imbalances (IQI) problem in the recent discrete sine transform based Orthogonal frequency division multiple access (DST-OFDMA) and discrete sine transform based single-carrier frequency division multiple access (DST-SC-FDMA) is investigated and compensated. IQI problem is investigated in three scenarios, transmitter IQI scenario (TX IQI scenario), receiver IQI scenario (RX IQI scenario) and transmitter- receiver IQI scenario (TX-RX IQI scenario), with different subcarriers mapping for both FDMA systems. The simulation results show that the mismatch in the phase and amplitude between the two branches of local oscillator in the receiver scenario introduces a significant performance degradation of the both FDMA systems more than transmitter scenario. Thereby, a correction scheme is proposed in this paper in the RX IQI scenario to face the degradation in the performance.
Keywords: IQI, DCR, DST-OFDMA, DST-SC-FDMA
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #32, pp. 292-298
Title of the Paper: Level Crossing Rate of Macrodiversity SC Receiver Output Process in the Presence of Weibull Short Term Fading, Gamma Long Term Fading and Weibull Cochanell Interference
Authors: Danijela Aleksić, Dragana Krstić, Zoran Popović, Mihajlo Stefanović
Abstract: In this paper, macrodiversity reception with macrodiversity (MAD) selection combining (SC) receiver and two microdiversity (MID) SC receivers operating over Gamma shadowed Weibull short term fading channel in the presence of cochannel interference subjected to Weibull multipath fading is observed. Level crossing rate (LCR) of the ratio of two Weibull random processes is evaluated and this expression is used for calculation the LCR at the output of MID SC receivers. The closed form expression of LCR at the output of MAD SC receiver is also determined. The influence of Gamma long term fading severity parameter, Gamma long term fading correlation coefficient, Weibull fading nonlinearity parameter of desired signal and Weibull fading nonlinearity parameter of cochannel interference on LCR of MAD system is studied and discussed.
Keywords: cochannel interference, Gamma long term fading, Level crossing rate (LCR), Weibull short term fading
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #31, pp. 285-291
Title of the Paper: Cooperative Game Theory as a Strategy of Resource Optimization in PLC Networks
Authors: Juan C. Vesga, Javier E. Sierra, Gerardo Granados
Abstract: The communications standard for powerline HomePlug AV (HPAV) uses CSMA/CA and TDMA as media access mechanism, where CSMA/CA is designed for transmitting data packets, while TDMA is used for voice and video packets transmission, in order to provide adequate levels of QoS [1]. However, although HPAV can achieve high rates of transmission, it does not have an adequate mechanism for resources allocating, which greatly affects the performance of the network as the number of users increases because to the fact that only one node can transmit at the same time [2]. The objective of this paper is to evaluate the behavior of four techniques: Shapley Value, Nucleolus, Max-min Fairness and MmQoS; as strategy for resources allocating in a channel PLC, when considering the HAN network as a cooperative game of transferable Utility. To make an efficient comparison of the four methods of optimization, it proposes the use of two HAN network scenarios under conditions of saturation. In each scenario it will be applied the four resource optimization methods and by Dunnett’s test it will identify what or what methods, or treatments yield the best results during the evaluation process. Upon completion of the analysis of the results, it is concluded that, for the proposed scenarios the value of Shapley was the technique that made a better allocation of BW, to minimize the difference between the BW requested value and BW value assigned to each node, with 95 % confidence.
Keywords: Cooperative game theory, Homeplug AV, Local area network, Max-Min Fairness, MmQoS, Nucleolus, Powerline communications, Resources optimization, Shapley Value
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #30, pp. 268-284
Title of the Paper: Evaluation of Models Hybrid (MH) and Smart (MS) Based on Game Theory for Resources Allocation in HomeplugAV Networks
Authors: Juan C. Vesga, Javier E. Sierra, Gerardo Granados
Abstract: The communications standard by powerline HomePlug AV does not have an appropriate resource optimization mechanism for a multiuser environment, which significantly affects the network performance when the number of users increases.In light of the foregoing, it is proposed the use of the Smart Model (SM) that uses the cooperative game theory, and especially the bankruptcy problem and the Shapley value, as a strategy to optimize the allocation of bandwidth on each node, according with the demand in the service, the number of stations and PLC channel conditions. The article presents a scenario under saturated traffic conditions to validate whether the proposed model (SM-HPAV) operates better than the model that uses HomePlug AV (HM-HPAV). The evaluation process presented favorable results for SM-HPAV which shows that the use of the cooperative game theory, supported on the Shapley value can be regarded as an excellent alternative when performing optimization processes bandwidth in a channel PLC and with the possibility to be implemented in low-cost embedded systems because it does not require complex operations for estimation, significantly improving levels of throughput, delay and efficiency of PLC technology.
Keywords: Cooperative Game Theory, Homeplug AV, Network Modelling, Powerline Communications, Resources Optimization
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #29, pp. 251-267
Title of the Paper: Modification of an Energy-Efficient Virtual Network Mapping Method for a Load-Dependent Power Consumption Model
Authors: Hiromichi Sugiyama, Yukinobu Fukushima, Tokumi Yokohira
Abstract: This paper tackles an energy efficient virtual network mapping problem where virtual nodes and links in a given virtual network have to be mapped to physical nodes and paths in a physical network so that the total power consumption associated with the mapping is minimized. The conventional method assumes that power consumption of a physical node is constant regardless of its load (constant power consumption model), and successfully reduces the total power consumption by preferentially mapping virtual nodes and links to active (used) physical nodes and paths passing only active physical nodes. However, power consumption of a physical node will become variable dependent on its load (variable power consumption model) in the near future, and the conventional method may not reduce the total power consumption because its active-node-first policy can cause large additional power consumption under the variable power consumption model. In this paper, we try to minimize the total power consumption under the variable power consumption model. In order to achieve this, we modify the conventional method so that it adopts the minimum-additional-power-consumption-first policy. The modified method calculates the actual additional power consumption associated with node and link mapping, and preferentially assigns virtual nodes and links to physical nodes and paths so that the actual additional power consumption is minimized. Simulation results clarify that the modified method can 4-40% lower total power consumption than the conventional method under the variable power consumption model.
Keywords: Network virtualization, Virtual network, Virtual network mapping problem, Energy efficiency, load-dependent power consumption model, heuristic algorithm
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #28, pp. 240-250
Title of the Paper: Internet Access Link Speed Between ISPs’ Myths and Subscribers’ Expectations
Authors: Mohammad Z. Masoud, Yousef Jaradat, Ismael Jannoud, Omar Al-Heyasat
Abstract: Due to the eruption of Internet contents and the need to interact with these contents quickly, Internet speed and subscribers’ download and upload bandwidths become important limiting issues. Increasing the purchased bandwidth from Internet Service Provider (ISP) can mainly solve these issues. However, the purchased bandwidth is not the real bandwidth subscribers obtained and paid for. Many factors impact the real obtained bandwidth. One of these important factors is the time of the day a subscriber access the Internet. In this work, we attempt to measure Internet connection speed over time. The recorded values proved the impact and effect of time on the speed and quality of the purchased bandwidth. To this end, we proposed a prediction models based on time series analysis and nonlinear autoregressive with exogenous input (NARX) neural network to predict the actual Internet connection bandwidth over time. Two NARX models have been implemented; the first one is for the download bandwidth and the other is for the upload bandwidth. These models obtained 86% and 88% in the validation test. These models can be utilized to predict the actual bandwidth an ISP can offer to a customer.
Keywords: Time Series, Nonlinear autoregressive with external input (NARX), Bandwidth, Internet Speed, Neural Network
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #27, pp. 233-239
Title of the Paper: Slope Intercept Model Estimation for MIMO–OFDM System in the WiMAX Environment
Authors: K. V. N. Kavitha, Kalapraveen Bagadi
Abstract: Channel fading in complex as well as in erratic manner, a rare spectrum of radio type, restrictions on the energy and the dimensions of mobile nodes are the prime restraints in communications of wireless type. Centred on these limitations novel schemes are put forth. Worldwide Interoperability for Microwave Access (WiMAX) is a promising domain to pursue work for wireless communication of broadband type, amidst a variety of emerging schemes. The scheme of WiMAX is a consistent method among IEEE 802.16d and among the principal of the WiMAX schemes, one can name Orthogonal Frequency Division Multiplexing (OFDM) as the core. A model of practical channel is needed to analyse the WiMAX method’s performances. Inclusive of Stanford University Interim (SUI) channel also known as slope intercept model, several models of channel are suggested to replicate the global situation. Lime light shone on this scheme prompting many a researchers to pursue in the recent past. Employing a variety of SUI models of channel, this paper analyses the performances in the context of Normalized Means Square Error (NMSE) of IEEE 802.16d. By analysing performance of different algorithms, proficient channel estimation scheme is arrived.
Keywords: MWA, MIMO-OFDM, SUI, Channel Estimation, NMSE
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #26, pp. 224-232
Title of the Paper: Data-Collecting Protocol Based on a Rooted Tree for Wireless Ad Hoc Networks Constructed Using Data Transmission Modems
Authors: Satoru Ohta
Abstract: This paper presents a simple communication protocol that effectively enables a base station to collect data from nodes in wireless ad hoc networks. The proposed protocol assumes that the network is constructed using a data transmission modem that uses a lower frequency radio wave than that employed by the frequently used systems such as wireless LANs or ZigBee. Since a lower frequency radio wave is advantageous because of less signal attenuation, the modem can provide a more reliable wireless link. Unfortunately, the modem does not support network functions. To construct a network with the modem and collect data from nodes, an appropriate communication protocol is required. The protocol must avoid packet collision because radio waves transmitted from nodes may generate interference. In addition, since the network is multihop and has mesh topology, a routing mechanism is necessary. To satisfy these requirements, the proposed method employs a token-passing approach that utilizes a rooted tree structure, which is extracted from a given network. By utilizing the tree structure, the routing mechanism is significantly simplified. Furthermore, packet collisions are eliminated by the token circulated in a tree. The algorithm that extracts a rooted tree from a given network is also shown. The feasibility and performance of the proposed protocol was examined on a prototype network.
Keywords: ad hoc network, tree, routing, token passing, communication protocol, wireless network
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #25, pp. 215-223
Title of the Paper: Weight Optimization for Adaptive Antenna Arrays Using LMS and SMI Algorithms
Authors: Mohammed Al-Sadoon, Raed A. Abd-Alhameed, I. T. E. Elfergani, J. M. Noras, Jonathan Rodriguez, S. M. R. Jones
Abstract: Wireless communication systems often suffer problems from multipath and interfering signals. This paper compares two types of adaptive beamforming algorithms for optimising and setting the weights of smart antenna systems, namely the Least Mean Square algorithm (LMS) and Sample Matrix Inversion (SIM). The direction of the main beam of the antenna system is adjusted to enhance the desired signal, while interfering signals are mitigated by having nulls pointed in their directions. The mathematical formulations and necessary conditions for the above algorithms are derived and verified by numerical examples, with overall behaviour obtained by MATLAB simulation. Performance evaluations are made for different cases of arrival angles, and in conclusion, the advantages and disadvantages of each algorithm are presented.
Keywords: Adaptive beam forming, Antenna array, Least Mean Square algorithm (LMS), Sample Matrix Inversion (SIM), Smart Antennas, Wireless communications
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #24, pp. 206-214
Title of the Paper: Quality of Service (QoS) Analysis for Decentralized Passive Optical Network (PON) Intelligent Algorithm
Authors: Sajaa Kh. Sadon, Sufian M. Mitani, Thavamaran Kanesan, Hizamel M. Hizan, Romli Mohamed
Abstract: Bandwidth controlling especially Decentralized Dynamic bandwidth allocation (DBA) is one of the essential issues in design and implementing PON system that has been studied by many researches. This paper introduces the QoS analysis for the decentralized DBA concepts on EPONs based on intelligent agent protocol and its intelligent bandwidth allocation. The approaches aim to distribute the bandwidth controlling from only OLT to inside each ONU in an intelligent way. The proposed decentralized traffic controllers using IDDBA based on intelligent agent’s in EPON could enhance the network performance specification as it will be proved in this paper by breaking down the complexity of upstream congestion problems in to simpler problems handled by distributing the simulation design system to improve the QoS.
Keywords: QoS, Bandwidth allocation, EPON, intelligent algorithms, wasted bandwidth
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #23, pp. 202-205
Title of the Paper: Three-Dimensional Communication Channel Model of UAV Data Link
Authors: Zhou Jianming
Abstract: In the paper, it makes analysis the characteristics of UAV communication channel in the tree-dimensional space. The UAV small scale model base on multipath propagation is analyzed, the fundamental conditions, extended function of azimuth angle and extended function of pitch angle are researched, which are satisfied with WSS (Wide-Sense Stationary) model. The three-dimensional system of coordinate is established, the parameter of channel is set, the line-of-sight component, reflecting component and scattering multipath component and the function related with time are analyzed and calculated, finally, three-dimensional model of UAV communication channel is established and related simulation is done to testify its validity.
Keywords: UAV, Data Link, Channel Model, Three-dimensional
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #22, pp. 188-201
Title of the Paper: Towards Resilient Mission Critical Broadband Data Communications for Public Protection and Disaster Relief
Authors: Jyri Rajamäki, John Holmström
Abstract: Mobile broadband applications can greatly improve the effectiveness of public protection and disaster relief (PPDR) operations, however, most PPDR actors do not have these capabilities. This design science research develops a multichannel solution for critical data broadband communications based on Distributed Systems intercommunication Protocol (DSiP) software, and evaluates it in an operational environment. We also propose resilience metrics for public safety communications (PSC) and analyze how our solution fulfils their objectives, and what should be developed further. Based on our findings, we have created additions to the knowledge base with regard to multichannel communications and PSC. However, much more research and development work is needed for making mission critical broadband data communications more resilient.
Keywords: Resilience, Mission critical, Public safety communications, Public safety mobile broadband, Distributed Systems intercommunication Protocol, Multichannel communications
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #21, pp. 176-187
Title of the Paper: Wideband Spectrum Sensing by Multistep Frequency Domain Energy Detection in GNU Radio
Authors: Shuya Dong, Xiaoqin Wu, Yong Bai
Abstract: Wideband spectrum sensing capability can be enabled in GNU Radio, which is an open source software radio platform. In order to improve the detection performance of GNU Radio in practice, we studied its approach of wideband spectrum sensing, i.e., multistep frequency-domain energy detection. We first gave a detailed analysis of the functions and implementation details in its wideband spectrum sensing procedure. Then, we simulated the whole procedure of the wideband spectrum sensing by using MATLAB. With the simulation results, we discussed the factors influencing the decision threshold of energy detection and proposed a method to determine the decision threshold for each step in the multistep detection. The results presented in this paper can be used for setting parameters of GNU Radio to achieve more precise spectrum sensing.
Keywords: Spectrum sensing, energy detection, GNU Radio
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #20, pp. 168-175
Title of the Paper: Image Super-Resolution Using Compressed Sensing Based on Learning Sub Dictionary
Authors: Muhammad Sameer Sheikh, Qunsheng Cao, Caiyun Wang
Abstract: Many applications have benefited remarkably from high resolution (HR) imaging models such as, astronomical and biomedical imaging system. In recent years, image enhancement and resolution approach has been embark the great result, and received great deal of attention of the researcher, and many researchers have proposed several methods to achieve the goal of high resolution image. In this paper an efficient method of high resolution image based on the concept of Compressed Sensing (CS) have been introduced, which uses sub dictionary instead of redundant dictionary and traditional orthogonal basis. The new framework is consisted of three phases. Firstly, we designed the sub dictionary that are learned from a range of datasets of high quality patches and then selected adaptively. Secondly, Principal Component Analysis (PCA) has been applied to each data sets of the high quality patches to evaluate the principal component from which the dictionary is constructed. Finally, the HR image is generated by averaging all high resolution patches. In addition, the proposed method has been demonstrated better results on real images in terms of peak to signal and noise ratio (PSNR), structural similarity (SSIM) and root mean square error (RMSE). Furthermore, our method has been evaluated by deriving the modulation transfer function (MTF), the MTF curve showed better reconstruction of HR image and achieved various improvements compared with other methods.
Keywords: Compressed Sensing, Compact Dictionary, Image Resolution, Modulation Transfer Function, Principal Component Analysis (PCA)
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #19, pp. 156-167
Title of the Paper: QoE Aware Player Using Playing Rate Adaptation for Progressive Download Services over Broadcast Networks
Authors: Zeki Yetgin, Semih Utku
Abstract: In this paper, a QoE (quality of experience) aware player is introduced that changes the temporal characteristics of streaming according to subjective parameters to increase the QoE. With the proposed player, two contributions are provided. First, the capability of rate adaptation methods is further enhanced by the playing rate adaptation where playing some video segments in negligible reduced rate is argued to provide better QoE than the ones degraded by start-stop failures that otherwise would be possible. Second, the temporal distribution of the start-stop failures can be modelled according to the user preference so that user‘s expectancy is better satisfied. Currently, start-stop failure has the dominant effect on QoE since the other types of streaming errors, such as color distortions, can be significantly avoided with the protection of the streaming channels against packet losses, e.g. using Forward Error Correction. With the channel protection, the overall network errors are projected onto behaviors of the buffering model. The buffering should be described by well-defined states and expected behaviors in that expected behaviors, from the user expectation point of view, are better than the random ones. As a case study, the streaming service is considered to be progressive downloading over 3GPP’s MBMS (multimedia broadcast multicast service) as the underlying network. In order to prove the accuracy of the proposed model, objective and subjective study using DSIS (double stimulus impairment scale) and DSCS (double stimulus comparison scale) are provided. The results show that QoE aware player increases the user satisfaction from the service.
Keywords: QoE, Streaming, Playing Rate Adaptation, MBMS, Progressive Download
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #18, pp. 147-155
Title of the Paper: Skyline Method In Wireless Ad-Hoc Networks Routing
Authors: Fadoua Yakine, Manar Abourezq, Abdellah Idrissi
Abstract: Unlike conventional routing protocols, in this paper, we address the problem of supporting unicast sessions with Quality of Service (QoS) requirements, using a new approach based on the Skyline operator. We have developed an algorithm that selects the routes while optimizing four characteristics related to routing, namely the number of hops, bandwidth, delay and cost. To evaluate the effectiveness and efficiency of our proposed algorithm, we compare its performance by simulation with an ILP algorithm based on a QoS constrained formulation.
Keywords: Wireless Ad Hoc Network, Routing, Unicast, QoS, Skyline, Block-Nested Loops Algorithm
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #17, pp. 137-146
Title of the Paper: Security Architecture for Wireless Sensors
Authors: Faruk Bagci, Ebrahim A. Alrashed
Abstract: As the potential range of applications for sensor networks expands, the need for security mechanisms grows. Security relevant problems are limited mostly to areas such as key distribution and cryptographic algorithms, due to severe resource constraints in wireless sensor networks. Even if it is not possible to cover all threats, a security architecture for sensor networks should provide mechanisms on several levels, in order to maximize the obstacles for attackers. This paper presents an architecture that provides basic security components for wireless sensor networks on multiple system levels. Since robust and strong security features require powerful nodes, the security architecture uses a heterogeneous sensor network. In addition to a large number of simple (cheap) sensor nodes providing the actual sensor tasks, there are a few powerful nodes (cluster nodes) that implement the required security features. The basic component of the architecture offers authenticated broadcasts to allow recipients to authenticate the sender of a message. On the basis of this basic component, our security architecture provides a key management, used for exchange of secret keys among nodes. In order to bind nodes to their neighborhood, keys and their owners are linked together. This ensures a certain grade of location relationship. To protect the sensor network against routing attacks, the security architecture includes a probabilistic multi-path routing protocol, which supports the key management and the authenticated broadcasts. The security system also provides functions to detect forged sensor data by verifying data reports en-route. In order to evaluate the efficiency of our security architecture, we simulated different sizes of sensor networks. Furthermore, the security architecture is successfully evaluated in a real test environment with two different kinds of sensor boards.
Keywords: wireless sensor network, security architecture, key management, energy efficiency, multi-path routing, en-route filtering
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #16, pp. 125-136
Title of the Paper: MxCHOKe: To Choke Anomalous Traffic with a Mix Matching Algorithm of Flow ID and IP for Various Network Congestion Avoidance
Authors: Haibo Tan, Xiaofeng Li
Abstract: Active Queue Management (AQM) plays an important role in network congestion control. Most of AQM algorithms aim to achieve flow fairness. However, with an investigation to congestion-cause traffic, the anomalous packets vary in different aggregating methods, not just within limited high-bandwidth flows. Therefore the previous AQM would lost the ground to penalize the misbehaved traffic scattered in distributed flows. In this paper, an escalated and mix matching of flow ID and IP algorithm (named MxCHOKe) has been proposed for various network congestion avoidance based on their statistical behavior. Simulation results suggest it gained an expected performance of protecting well-behaved traffic in more realistic congested situations.
Keywords: Active Queue Management, Anomalous Traffic, Congestion Control, Approximate Fairness
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #15, pp. 120-124
Title of the Paper: Performance of SC Receiver over Weibull Multipath Fading Channel
Authors: Srdjan Maričić, Dragana Krstić, Mihajlo Stefanović, Muneer Masadeh Bani Yassein, Vladeta Milenković
Abstract: The wireless communication system with dual selection combining (SC) diversity receiver operating over Weibull short term fading channel in the presence of cochannel interference affected to Weibull multipath fading, is considered in this paper. Weibull fading can be used to describe signal envelope variation in nonlinear fading environment. Cumulative distribution function and the level crossing rate of the ratio of two Weibull random variables are evaluated and these expressions are used for calculation the level crossing rate of dual SC receiver output signal envelope. These results can be availed for evaluation of the average fade duration of proposed communication system. The series in derived expressions rapidly converge for every values of fading parameters. The influence of Weibull fading parameter on level crossing rate is analyzed and studied.
Keywords: Level crossing rate, outage probability, ratio of two random variables, SC receiver, Weibull fading
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #14, pp. 114-119
Title of the Paper: A Low Complexity Individual Process Fix-LLL Algorithm for MIMO System
Authors: Huazhang Lv, Jianping Li, Weibo Qiu
Abstract: The Lenstra-Lenstra-Lovász (LLL) algorithm is an effective lattice reduction method in multi-inputmulti-output (MIMO) systems. Its modified version Fix-LLL (F-LLL)unilaterally aims to largely decrease the computation complexity in size reduction, but size reduction in LLL algorithm is closely associated with column swap procedure. This characteristic is harmful to independently design an optimum proposal for these two algorithmic parts. In this paper, a novel individual process F-LLL algorithm divides the overall process of LLL algorithm into two individual procedures. The column swap procedure of the novel algorithm is modified by searching for the potential column swaps through the whole basis. Until no basis is selected, the procedure terminates and global size reduction is achieved. We mainly design two schemes for selecting potential column swaps: offset coefficient selection criterion (OCSC) and maximum slope selection criterion (MSSC). Simulation results show both OCSC-F-LLL and MSSC-F-LLL can reduce computation complexity and performance loss compared to the LLL algorithm.
Keywords: LLL algorithm, lattice reduction, individual process, MIMO system
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #13, pp. 105-113
Title of the Paper: The Influence of Bit Error Rate on Four-Channel Wavelength Division Multiplexing System with the Channel Spacing of 4 nm in C Band with the Speed of 10 Gbps and Three Different Pumping Powers in an Optical Fibre Amplifier of 980 nm
Authors: Petr Ivaniga, Tomáš Ivaniga
Abstract: This article focuses on the simulation of four-channel WDM (Wavelength Division Multiplexing) system with the spacing of 4 nm and the speed of 10 Gbps. It underlines the error rate BER (Bit Error Rate) which changes with the input power of fibre amplifier EDFA (Erbium Doped Fibre Amplifier) for the respective channel of WDM. Nowadays while designing the WDM it cannot be done without software tools simulating a real network to avoid possible mistakes which could occur before the actual construction of communication systems. Simulation solves the creation of WDM from 1554 to 1566 nm with the best error rate for the respective channel using single-mode optical fibre 40 km long with measurable attenuation constant according to ITU-T G-652-D.
Keywords: Bit Error Rate, Erbium Doped Fibre Amplifier, Q-factor, Wavelength Division Multiplexing
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #12, pp. 98-104
Title of the Paper: Sparse Multipath Channel Estimation for SC-FDE System with Unknown Sparsity
Authors: Xiaoling Li, Yulang Zheng, Yong Bai
Abstract: The performance of Single Carrier Frequency-Domain Equalization (SC-FDE) system is affected by the precision of channel estimation results. For a pilot-assisted SC-FDE system transmitting over sparse multipath radio channels, we discuss that the sparse multipath channel estimation can be formulated to be an underdetermined compressed sensing (CS) problem or an overdetermined sparse system identification problem under different transmission parameters. For the sparse system identification problem setting, we propose to use Zardoff-Chu sequence as the pilot sequence to form a deterministic circulant Toeplitz observation matrix for signal recovery. To address the unknown sparsity in practical applications, Sparsity Adaptive Matching Pursuit (SAMP) algorithm is investigated to reconstruct the channel impulse response (CIR) instead of other greedy sparse recovery algorithms that need a priori knowledge of channel sparsity. The simulation results demonstrate that using the designed observation matrix and the SAMP algorithm for sparse channel estimation with unknown sparsity achieves better performance than the traditional Least Squares (LS) channel estimation algorithm with reduced length of pilot sequence in the SC-FDE system over 3GPP radio channels.
Keywords: SC-FDE, Channel estimation, Compressed sensing, Orthogonal Matching Pursuit, Sparsity Adaptive Matching Pursuit
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #11, pp. 87-97
Title of the Paper: Cooperative Amplify-and-Forward Relaying Systems with Quadrature Spatial Modulation
Authors: Ibrahem E. Atawi
Abstract: Quadrature spatial modulation (QSM) is a recent digital multiple-input multiple-output (MIMO) transmission technique. Combined with cooperative relaying, QSM improves the overall spectral efficiency and enhances the communication reliability. In this paper, we study the performance of QSM amplify-and forward cooperative relaying systems. In particular, a closed-form expression for the average pair-wise error probability (PEP) of the cooperative system is derived, which is used to calculate a tight upper bound of the average bit error probability (ABEP) over Rayleigh fading. In addition, a simple approximate, yet accurate expression is derived and analyzed asymptotically. Simulation results, which corroborate the numerical ones, show the effectiveness of combined QSM and cooperative relaying in improving the overall system performance.
Keywords: Amplify-and-forward, Quadrature spatial modulation, Spectral efficiency, MIMO
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #10, pp. 82-86
Title of the Paper: A Fuzzy Logic Based Next-Hop Selection Scheme for Emergency Message Propagation in VANETs
Authors: Chunxiao Li, Jun Sun, Jing Yang, Dawei He, Jun Wu, Mei Sun
Abstract: Vehicle Ad hoc Networks (VANETs) with a large number of roadside and vehicle on board devices can provide various services for users. To improve the road safety services, the emergency message generated by safety-related devices which are closest to the dangerous spot should be propagated to the other nearby vehicles immediately when road traffic accidents or dangers are detected. As road safety is a time-criticality problem, so choosing a suitable next-hop is very important for in time message propagation under unicast situations. To address this, this paper presents a next-hop selection scheme in VANETs for propagating and relaying emergency message. A fuzzy logic time-distance headway based next-hop selection scheme is proposed, which has considered the influences of the following three factors: distance headway factor, time headway factor and signal strength factor. Compared with the conventional next-hop selection schemes, the number of informed vehicles and the probability to inform a vehicle both have much better performances than the conventional schemes. Therefore, the proposed next-hop selection scheme for propagating emergency message from the safety-related devices can be used to keep road safety by avoiding unnecessary road collisions.
Keywords: Fuzzy logic time-distance headway, next-hop, emergency message, road safety
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #9, pp. 72-81
Title of the Paper: Two New Algorithms of Signal Processing in the Communication System with Information Feedback
Authors: Vladimir Kazakov, Francisco Tejeda
Abstract: The signal processing in the receivers of both channels is carried out with elementary signals. The direct channel receiver has memory. The threshold control in the feedback channel receiver is the main goal of the present article. The first algorithm on the criterion of minimum error probability without any restriction is investigated. The result is the set of thresholds changed in the repetitions. The second algorithm is investigated when the consumption of energy is introduced. This problem is solved on the method of the conditional optimization. Once again, the set of thresholds is obtained. The effectiveness of the mentioned two new algorithms is compared with the simple algorithm, when thresholds do not change with the number of repetition.
Keywords: Communication system with information feedback, error probability
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #8, pp. 64-71
Title of the Paper: Energy-Balanced Clustering Routing Protocol Based on Task Separation in Wireless Sensor Networks
Authors: Wei Sun, Xiaoying Song, Fasheng Wang
Abstract: Clustering protocol for data gathering is one of the effective ways to solve energy hole problem in wireless sensor networks. However, most of the existing clustering protocols focus on the network model with uniform node distribution. They do not effectively apply to the real network where the sensor nodes are randomly non-uniformly deployed. In this paper, we propose an energy-balanced clustering routing protocol (EBCRP) based on task separation. In this scheme, the network is firstly divided into clusters by using global information. And each of them has the same number of sensor nodes in order to balance the energy consumption of intra-cluster. In succession, task separation, the tasks of traditional single cluster head are separated and achieved by two cluster heads respectively, is proposed to reduce the traffic burden for single cluster head. Then, we explore an energy-efficient and reliable inter-cluster routing algorithm, which considers comprehensively three factors: residual energy, distance and available buffer space of nodes. Simulation results and performance evaluation of EBCRP show significant improvement in network lifetime and energy balance.
Keywords: Wireless Sensor Networks, Balancing Energy Consumption, Task Separation, Clustering Routing Protocol, Random Deployment
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #7, pp. 54-63
Title of the Paper: Traffic Estimation Through Mobile Network Performance Data Processing
Authors: Vasileios Asthenopoulos, Ioannis Loumiotis, Pavlos Kosmides, Evgenia Adamopoulou, Konstantinos Demestichas
Abstract: This paper presents the concept of using mobile network performance data in order to estimate and predict road traffic conditions. The effectiveness of the approach taken by the authors is examined using realworld data acquired from mobile and road network operators. Furthermore, a comparative analysis is performed to evaluate which of the two machine learning techniques proposed, namely the Multi-Layer Perceptron and the General Regression Neural Network is more suitable for this purpose. It is argued that practical implementations of the system described in this paper can reduce the number of sensors needed to acquire metrics from the road network, allow accurate estimation of future road traffic conditions exclusively using anonymous mobile network performance data, and even raise near real-time alerts about traffic events, without the requirement of dedicated traffic sensors.
Keywords: ITS, cellular data, traffic prediction, MLP, GRNN, Vehicle Detection System, mobile network
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #6, pp. 48-53
Title of the Paper: Performance Analyses on OFDM-PON in Coherent Detection Schemes
Authors: Mingzhi Mao, Rongrong Chen, Caixia Kuang, Rujian Lin
Abstract: Performance analyses are presented theoretically on OFDM-PON working in IQ modulation-heterodyne detection scheme for downstream and in intensity modulation-homodyne detection scheme for upstream which include the characterization of non-linear distortion in IQ modulator, pilot light multiplexing for optical phase noise cancellation in ONU receiver, heterodyne detection with LO provided by sharing the seed light power to RSOA?downstream system optimization and non-linear optical phase noise cancellation in OLT receiver. Simulation and experiment show that the receiver sensitivity can reach –(21~27) dBm for downstream light at single wavelength carrying 64/16 QAM-modulated OFDM signal in 2GHz band, when LO power is higher than –10 dBm and the receiver sensitivity can reach –20 dBm for upstream light at single wavelength carrying 16 QAM-modulated OFDM signal in1.6 GHz band, when LO power is high than 0 dBm.
Keywords: OFDM-PON, IQ modulator, Coherent Detection, Self Homodyne, Heterodyne, MQAM, Non-linear distortion, optical phase noise
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #5, pp. 37-47
Title of the Paper: Advanced Fuzzy Class-Based Routing in MPLS-TE Networks
Authors: Michal Pištek, Martin Medvecký
Abstract: The paper focuses on optimizing MPLS-TE networks using Constraint-Based Routing algorithm with implemented fuzzy logic. CBR includes routing algorithms that do not make routing decisions solely on the shortest path towards the destination but they can also base their decisions on various Quality of Service parameters or administrative needs. MPLS-TE networks can benefit from implementing such algorithms by utilizing less loaded paths or limiting the QoS parameters of the traffic to desired values. Implementing multiple constraints into algorithm can have issues with combining these constraints to make the decisions. Fuzzy logic represents an ideal tool for normalizing these constraints in [0,1] interval where the closer the constraint gets to 1, the better the path should be. The paper introduces a new CBR algorithm called Advanced Fuzzy Class Based Algorithm (AFCBA) which, besides setting the proper membership functions and cost calculations, deals with the tie break situations and what actions to take if no path satisfies the requirements of the traffic flows.
Keywords: Constraint Based Routing, Fuzzy Logic, MPLS, QoS, AFCBA, WSP, SWP
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #4, pp. 27-36
Title of the Paper: Error-Rate Performance of Selection Combining over Generalized Correlated Weibull Fading Channels
Authors: Qing Wang, Ju Liu
Abstract: Error-rate performance is studied for selection combining (SC) with arbitrary number of diversity branches over generalized correlatedWeibull fading channels. Using a transformation of cumulative distribution function of average branch signal-to-noise ratio (SNR), we present the exact error-rate expressions for coherent and non-coherent modulations in infinite series forms. In particular, we develop asymptotic symbol error rate expressions with closed-form which are valid at high SNR. Presented numerical examples show that taking the first several terms of the series based error-rate expression results in improved error-rate estimation compared to the asymptotic error-rate. These error-rate expressions which can be evaluated efficiently indicate some significant insights into the characteristics of SC over generalized correlated Weibull fading channels. The accuracy of the analytical results is validated by the simulation results.
Keywords: orrelated fading channels, error-rate performance, selection combining, Weibull distribution
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #3, pp. 18-26
Title of the Paper: Performance of Space Shift Keying Modulation over Generalized κ-μ Fading Channels
Authors: Mohammed M. Alwakeel
Abstract: This paper analyzes the performance of space shift keying (SSK) modulation for a generic multipleinput multiple-output (MIMO) wireless system operating over generalized κ - μ fading channels. In particular, an expression of the pair wise error probability (PEP) is obtained. In addition, simple and general asymptotic expression for the PEP is given. The derived expression for the PEP is general, such that the PEP over various well-known fading channels can be derived as special cases, such as Nakagami-m and Nakagami-n (Rice) fading channels. Numerical results are provided, sustained by simulation results, which corroborate the exactness of the theoretical analysis.
Keywords: Amplify-and-forward, Quadrature spatial modulation, Spectral efficiency, MIMO
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #2, pp. 10-17
Title of the Paper: Adaptive Energy-Efficient Power Allocation under Imperfect Channel Sensing in OFDM-Based Cognitive Opportunistic Relaying Links
Authors: Li Feng, Yujun Kuang, Xinchuan Fu, Binwei Wu
Abstract: This paper investigates energy efficient power allocation scheme for OFDM-based cognitive opportunistic relaying links (CORL), where secondary users (SUs) may incorrectly sense the unlicensed spectrum and hence transmit data in collision. We aim to maximize the energy efficiency (EE) by optimal and low complexity power allocation design. At first, an energy efficient power allocation optimization problem with imperfect sense is formulated, under the individual power budget and peak primary user’s (PU’s) interference constraints. Then, we focus on the analysis of the optimal non-convex power allocation problem, which is of great concern for the EE in CORL. At last, with the aid of the fractional programming method, an EE-oriented power allocation policy with low complexity is proposed which used the bisection method to speed up the search of the optimum. Numerical results are provided to corroborate our theoretical analysis and to demonstrate the effectiveness of the proposed schemes.
Keywords: Cognitive Opportunistic Relay, OFDMA, Energy Efficiency, Power Allocation, Spectrum Sensing Errors, Low Complexity
WSEAS Transactions on Communications, ISSN / E-ISSN: 1109-2742 / 2224-2864, Volume 15, 2016, Art. #1, pp. 1-9
