http://jwcn.eurasipjournals.com The latest research articles published by EURASIP Journal on Wireless Communications and Networking 2013-05-17T00:00:00Z This study aimed to find the effects of 12-week chiropractic and lumbar exercise program on the lumbar muscle strength and Cobb's angle in 16 adolescent students with scoliosis. The patients with scoliosis did not have neurological symptoms and surgery experience. Each group of eight subjects received chiropractic and lumbar exercises three times a week. Subjects' lumbar muscle strength measurement showed a statistically significant temporal difference in the chiropractic group (CG) and chiropractic with exercise group (EG) and had interaction effects. However, no significant difference was found between the two groups. Changes in the Cobb's angle in each group had a significant difference both temporally and between group in both CG and EG, and interaction effects were also significant. As suggested in this study, mutual application of exercise therapy program and chiropractic treatments was found to have a positive effect on lumbar muscle strength and Cobb's angle in patients with scoliosis. http://jwcn.eurasipjournals.com/content/2013/1/132 Minwoo Cheon Jaeyong Park Yangsun Lee Jungchul Lee EURASIP Journal on Wireless Communications and Networking 2013, null:132 2013-05-17T00:00:00Z doi:10.1186/1687-1499-2013-132 /content/figures/1687-1499-2013-132-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 132 2013-05-17T00:00:00Z PDF Since mobile hosts suffer from burst and location-dependent channel errors in wireless networks, packet fair queueing algorithm in wireline networks cannot be applied directly to wireless networks. Generally, a fair scheduler in a wireless network retains the virtual time of flow when the flow encounters channel errors. This results to the flow having higher priority when it exits from errors, and the system can compensate the lost service for the flow. This causes the lagging flows to capture the shared channel and affects the queueing delay of flows perceiving a clean channel. In this paper, we present a channel condition self-clocked packet scheduling scheme. This algorithm can address the problem and achieve the following goals: (1) steady delay and jitter for flows perceiving an error-free environment, (2) delay and throughput guarantees in an error-free environment, (3) short-term fairness among flows perceiving an error-free environment, and (4) long-term fairness for error system. Our algorithm is based on start-time fair queueing, and the virtual time of flows is reset to contend for forwarding its packet the next time when errors happen for the flow. http://jwcn.eurasipjournals.com/content/2013/1/131 Jyh-Ming Chen Eric Wu Hsiang-Wei Lu Ching-Hsiang Chu Meng-Feng Tsai EURASIP Journal on Wireless Communications and Networking 2013, null:131 2013-05-17T00:00:00Z doi:10.1186/1687-1499-2013-131 /content/figures/1687-1499-2013-131-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 131 2013-05-17T00:00:00Z PDF Tail-biting trellises are defined on a circular time axis and can have a smaller number of states thanequivalent conventional trellises. Existing circular Viterbi algorithms (CVAs) on the tail-biting trellisare non-convergent and sub-optimal. In this study, we show that the net path metric of each tail-biting path is lower-bounded during the decoding process of the CVA. This property can be appliedto remove unnecessary iterations of the CVA and results in a convergent maximum likelihood (ML)decoder. Simulation results show that the proposed algorithm exhibits higher decoding efficiencycompared with other existing ML decoders. http://jwcn.eurasipjournals.com/content/2013/1/130 Xiaotao Wang Hua Qian Kai Kang Weidong Xiang EURASIP Journal on Wireless Communications and Networking 2013, null:130 2013-05-17T00:00:00Z doi:10.1186/1687-1499-2013-130 /content/figures/1687-1499-2013-130-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 130 2013-05-17T00:00:00Z PDF We consider a cognitive radio network in which a multiple-accesssecondary system coexists with an automatic repeat request (ARQ)-based primary system under heavy primary traffic. To achievespectrum sharing without degrading the performance of the primarysystem, the secondary transmitters alternate between cooperation andaccess modes based on a credit system. In the cooperation mode, thesecondary transmitters serve as potential relays among which thebest one is selected to help forward the primary packet, thusaccumulating credits. These credits will then allow the secondarytransmitters to gain spectrum access by exploiting the ARQ mechanismof the primary system. Our results show that with a cluster ofclosely located secondary transmitters, the proposed spectrum sharing protocol achieves an equal average throughput for theprimary system compared to the case without spectrum sharing, whileproviding access opportunities for the secondary system.Furthermore, by increasing the number of secondary transmitters ordecreasing the distance between secondary transmitters and secondaryreceiver, an overall higher throughput can be achieved for thesecondary system, without affecting the analytical results for theupper bounds of primary throughput under cooperation mode, andsecondary throughput under access mode are also derived. http://jwcn.eurasipjournals.com/content/2013/1/129 Shu Fang See Ting Qiang Li Ashish Pandharipande Mehul Motani EURASIP Journal on Wireless Communications and Networking 2013, null:129 2013-05-13T00:00:00Z doi:10.1186/1687-1499-2013-129 /content/figures/1687-1499-2013-129-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 129 2013-05-13T00:00:00Z PDF The performance of underwater sensor networks (UWSNs) is greatly limitedby the low bandwidth and high propagation delay of acoustic communications.Deploying multiple surface-level radio-capable gateways can enhanceUWSN performance metrics, reducing end-to-end delays and distributingtraffic loads for energy reduction. In this paper, we study the problemof gateway placement for maximizing the cost-benefit of this UWSNarchitecture. We develop a mixed integer programming (MIP) gatewaydeployment optimization framework. We analyze the tradeoff betweenthe number of surface gateways and the expected delay and energy consumptionof the surface gateway architecture in the optimal case. We used anMIP solver to solve the developed optimization problem and integratedthe optimal results to serve as an input forour simulations to evaluate the benefits of surface gateway optimizationframework. We investigated the effect of acoustic channel capacityand the underwater sensor node deployment pattern on our solution.Our results show the significant advantages of surface gateway optimizationand provide useful guidelines for real network deployment. http://jwcn.eurasipjournals.com/content/2013/1/128 Saleh Ibrahim Manal Al-Bzoor Jun Liu Reda Ammar Sanguthevar Rajasekaran Jun-Hong Cui EURASIP Journal on Wireless Communications and Networking 2013, null:128 2013-05-13T00:00:00Z doi:10.1186/1687-1499-2013-128 /content/figures/1687-1499-2013-128-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 128 2013-05-13T00:00:00Z PDF With the rapid growth of broadband network deployment and multimedia streaming development, Internet protocol (IP) multicast networks have become a delivery mechanism for Internet protocol television (IPTV). IPTV provides a two-way interactive service to the viewers, which generates the path request for IP multicast network. Thus, it is essential to evaluate the path rejection probability accurately and further to reduce it. In this paper, we propose a new dynamic multicast routing algorithm for broadband IPTV services and apply it to three legacy algorithms. These integrated multicast routing algorithms support the minimum cost and the traffic engineering features, in order to maximize the acceptance rate for bandwidth constraint path request under IPTV service environments. Furthermore, we compare their network performances in terms of the acceptance rate and delay by experimental simulations. The simulation result gives us that the nearest node first Dijkstra algorithm can be the optimal solution of multicast connection for IPTV service delivery. http://jwcn.eurasipjournals.com/content/2013/1/127 Sungkwan Youm Taeshik Shon Eui-Jik Kim EURASIP Journal on Wireless Communications and Networking 2013, null:127 2013-05-11T00:00:00Z doi:10.1186/1687-1499-2013-127 /content/figures/1687-1499-2013-127-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 127 2013-05-11T00:00:00Z PDF In recent times, machine-to-machine (M2M) communication is considered the most promising solution for revolutionizing future intelligent pervasive applications. The capillary M2M network is a key component of the M2M system, and it should support a data rate that is sufficient to accommodate various vertical applications with limited resources of end devices. This paper presents a joint routing and scheduling (JRS) framework for a capillary M2M network. To achieve the conflicting goals of maximizing network performance and conserving energy, the JRS framework is designed with an integrated concept of routing and transmission scheduling, which provides time division multiple access (TDMA)-based transmission scheduling based on the established routing path of data. Moreover, to extend the number of available transmission frames and enhance network performance, JRS uses the multi-channel communication approach. Experimental results of the prototype implementation demonstrate that JRS outperforms conventional schemes, even under heavy traffic conditions. http://jwcn.eurasipjournals.com/content/2013/1/126 Taeshik Shon Hyo Choi Eui-Jik Kim EURASIP Journal on Wireless Communications and Networking 2013, null:126 2013-05-10T00:00:00Z doi:10.1186/1687-1499-2013-126 /content/figures/1687-1499-2013-126-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 126 2013-05-10T00:00:00Z PDF In this paper, we present a fundamental study on the stationarity and ergodicity of eight classes of sum-of-cisoids (SOC) processes for the modeling and simulation of frequency-nonselective mobile Rayleigh fading channels. The purpose of this study is to determine which classes of SOC models enable the design of channel simulators that accurately reproduce the channel's statistical properties without demanding information on the time origin or the time-consuming computation of an ensemble average.We investigate the wide-sense stationarity, first-order stationarity of the envelope, mean ergodicity, and autocorrelation ergodicity of the underlying random processes characterizing the different classes of stochastic SOC simulators. The obtained results demonstrate that only the class of SOC models comprising cisoids with constant gains, constant frequencies, and random phases is defined by a set of stationary and ergodic random processes.The analysis presented here can easily be extended with respect to the modeling and simulation of frequency-selective single-input single-output (SISO) and multiple-input multiple-output channels. For the case of frequency-selective SISO channels, we investigate the stationarity and ergodicity in both time and frequency of 16 different classes of SOC simulation models.The findings presented in this paper can be used in the laboratory as guidelines to design efficient simulation platforms for the performance evaluation of modern mobile communication systems. http://jwcn.eurasipjournals.com/content/2013/1/125 Bjørn Olav Hogstad Carlos Gutiérrez Matthias Pätzold Pedro Crespo EURASIP Journal on Wireless Communications and Networking 2013, null:125 2013-05-10T00:00:00Z doi:10.1186/1687-1499-2013-125 /content/figures/1687-1499-2013-125-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 125 2013-05-10T00:00:00Z PDF In this paper, we propose efficient signal waveforms (WFs) with optimized spectrum for multipath (MP) mitigation and jamming reduction in global navigation satellite system. These WFs are based on the use of sine-phased binary offset carrier (BOC) with adjustable width (BOC-AW). They are generated by adjusting the width of the three-level WF {-1, 0, 1}. By exploiting the three-level BOC-AW subcarriers in sine-phasing signal model, we developed several forms of BOC-AW by means of superposition and width adjustment. The resulting power spectral densities and autocorrelation functions of the proposed WFs were calculated and introduced. Also calculated were the spectral separation coefficients (SSCs) and the Cramer-Rao lower bounds (CRLBs). The SSCs and CRLBs prove the efficiency of the proposed WFs in terms of interference separation. In addition, the simulation results show that the proposed WFs present better performances in MP mitigation compared to the WFs adopted by the Galileo and global positioning system modernization. http://jwcn.eurasipjournals.com/content/2013/1/124 Mustapha Flissi Khaled Rouabah Djamel Chikouche Abdehalim Mayouf Salim Atia EURASIP Journal on Wireless Communications and Networking 2013, null:124 2013-05-09T00:00:00Z doi:10.1186/1687-1499-2013-124 /content/figures/1687-1499-2013-124-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 124 2013-05-09T00:00:00Z PDF Current researches define the perfect signal by the inner product of sequence itself and its delay sequence. However, these traditional sequences based on second-order statistics cannot handle colored Gaussian measurement noise automatically. Because higher-order cumulant (HOC) is insensitive to the adding Gaussian noise and symmetrical non-Gaussian noise, a new kind of perfect binary signal with good periodic correlation function based on HOC is presented. This paper proposes a new concept of perfect binary-third-order cyclic autocorrelation sequences (PBTOCAS) and defines the quasi-perfect binary-third-order cyclic autocorrelation sequences (QPBTOCAS) and the almost perfect binary-third-order cyclic autocorrelation sequences (APBTOCAS). Then the properties of these binary sequences are studied, and we theoretically prove that binary-third-order cyclic autocorrelation sequences can effectively suppress colored Gaussian noise. Finally, some QPBTOCAS and APBTOCAS with short lengths by computer searching are listed. From the observation of the PBTOCAS, we can see that it can well suit engineering applications, remedying the defect of the conventional pseudo-noise code used in very low signal-noise-ratio environments. http://jwcn.eurasipjournals.com/content/2013/1/123 Yi Zhong Zheng Zhou Ting Jiang EURASIP Journal on Wireless Communications and Networking 2013, null:123 2013-05-09T00:00:00Z doi:10.1186/1687-1499-2013-123 /content/figures/1687-1499-2013-123-toc.gif EURASIP Journal on Wireless Communications and Networking 1687-1499 ${item.volume} 123 2013-05-09T00:00:00Z PDF