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PHYSICS (573 journals)

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Journal Cover Physical Communication
  [SJR: 0.552]   [H-I: 19]   [1 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1874-4907
   Published by Elsevier Homepage  [3043 journals]
  • Spectrum mobility in cognitive radio network using spectrum prediction and
           monitoring techniques
    • Authors: Prabhat Thakur; Alok Kumar; S. Pandit; G. Singh; S.N. Satashia
      Pages: 1 - 8
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Prabhat Thakur, Alok Kumar, S. Pandit, G. Singh, S.N. Satashia
      The spectrum mobility during data transmission is an integral part of the cognitive radio network (CRN) which is conventionally two types for instance reactive and proactive. In the reactive approach, the cognitive user (CU) switches its communication after the emergence of the primary user (PU), where the detection of emergence of PU relies either on spectrum sensing and/or monitoring. Due to certain limitations of the reactive approach such as: (1) loss at least one packet on the emergence of PU and (2) resource (bandwidth) wastage if the periodic sensing is used for mobility, the researchers have introduced the concept of proactive spectrum mobility. In this approach, the emergence of PU is predicted on the bases of pre-available spectrum information, and switching is performed before true emergence of the PU, in order to avoid even the single packet loss. However, the imperfect spectrum prediction is a major milestone for the proactive spectrum mobility. Recently, due to introduction of the spectrum monitoring simultaneous to the data transmission, the reactive approach has come into lime-light again, however, it suffers from the ‘single packet loss’ and ‘imperfect spectrum monitoring’ issues. Therefore in this paper, we have exploited the spectrum monitoring and prediction techniques, simultaneously for the spectrum mobility, in order to enhance the performance of cognitive radio network (CRN). In the proposed strategy, the decision results of the spectrum prediction and monitoring techniques are fused using AND and OR fusion rules, for the detection of emergence of PU during the data transmission. Further, the closed-form expressions of the resource wastage, achieved throughput, interference power at PU and data-loss for the proposed approaches as well as for the prediction and monitoring approaches are derived. Moreover, the simulation results for the proposed approaches are presented and validation is performed by comparing the results with prediction and monitoring approach. In a special case, when the prediction error is zero, the graphs of all metric values overlies the spectrum monitoring approach, which further validates the proposed approach.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.005
      Issue No: Vol. 24 (2017)
  • Proportional fairness analysis of massive MIMO Two-tier multiuser downlink
           with subchannel pairing
    • Authors: Irfan Ahmed
      Pages: 9 - 18
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Irfan Ahmed
      This paper presents a proportional fairness throughput analysis of a millimeter wave massive multiple-input multiple output (MIMO) small base station (SBS)-assisted downlink with subchannel (SC) pairing. We derive an analytical expression for evaluating the average logarithmic throughput with SC-pairing and proportional fairness in two-tier network with amplify-and-forward (AF) and decode-and-forward (DF) SBSs. Analytical expressions are derived for the probability density function (PDF) of logarithmic throughput, and the average logarithmic throughput with statistical channel state information (CSI) based gain at AF SBS. It has been shown that the percentage error between simulation and analytical results decreases with increase in number of SC N and number of antennas, and is upper bounded by 0.28% and 0.79% when N ≥ 16 for AF and DF SBSs, respectively.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.001
      Issue No: Vol. 24 (2017)
  • A spectrum handoff scheme for optimal network selection in Cognitive Radio
           vehicular networks: A game theoretic auction theory approach
    • Authors: Krishan Kumar; Arun Prakash; Rajeev Tripathi
      Pages: 19 - 33
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Krishan Kumar, Arun Prakash, Rajeev Tripathi
      The recent strides in vehicular networks have emerged as a convergence of multi radio access networks having different user preferences, multiple application requirements and multiple device types. In future Cognitive Radio (CR) vehicular networks deployment, multiple radio access networks may coexist in the overlapping areas having different characteristics in terms of multiple attributes. Hence, it becomes a challenge for CR vehicular node to select the optimal network for the spectrum handoff decision. A game theoretic auction theory approach is interdisciplinary effective approach to select the optimal network for spectrum handoff. The competition between different CR vehicular node and access networks can be formulated as multi-bidder bidding to provide its services to CR vehicular node. The game theory is the branch of applied mathematics which make intelligent decision to select the optimal alternative from predetermined alternatives. Hence, this paper investigates a spectrum handoff scheme for optimal network selection using game theoretic auction theory approach in CR vehicular networks. The paper has also proposed a new cost function based multiple attribute decision making method which outperforms other existing methods. Numerical results revel that the proposed scheme is effective for spectrum handoff for optimal network selection among multiple available networks.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.001
      Issue No: Vol. 24 (2017)
  • Modeling the lossy transmission of correlated sources in multiple access
           fading channels
    • Authors: Antonios Argyriou; Özgü Alay; Panagiotis Palantas
      Pages: 34 - 45
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Antonios Argyriou, Özgü Alay, Panagiotis Palantas
      In this paper, we develop accurate distortion models for the lossy transmission of two correlated sources in a multiple access Rayleigh fading channel. We focus on a class of real-life communication systems, where the source and channel coders have already been designed separately and can only be configured during the system operation. We investigate three different source coding schemes: distributed source coding (DSC), layered source coding, and independent compression through quantization. With the later scheme the sources are jointly decoded with minimum mean square error (MMSE) estimation at the receiver. We also consider two different transmission schemes: Orthogonal transmissions and interfering transmissions decoded with a successive interference cancellation (SIC) decoder. Our final closed-form analytical models are used to determine the optimal combination of source coding and transmission schemes, as well as their optimal configuration. Hence, we exercise joint source and channel coding (JSCC) by optimizing the system configuration. Through simulations, we first validate the analytical model and illustrate the performance of different schemes. Finally, we demonstrate the JSCC gains achieved by our system.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.003
      Issue No: Vol. 24 (2017)
  • Waveform contenders for 5G: Description, analysis and comparison
    • Authors: Jean-Baptiste Doré; Robin Gerzaguet; Nicolas Cassiau; Dimitri Ktenas
      Pages: 46 - 61
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Jean-Baptiste Doré, Robin Gerzaguet, Nicolas Cassiau, Dimitri Ktenas
      5G will have to cope with a high degree of heterogeneity in terms of services and requirements. Among these latter, flexible and efficient use of all available non-contiguous spectra for different network deployment scenarios is one challenge for the future 5G. To maximize spectrum efficiency, a flexible 5G air interface technology capable of mapping various services to the best suitable combinations of frequency and radio resources will also be required. In this work, a fair comparison of several 5G waveform candidates (UFMC, FBMC-OQAM, and FBMC-QAM) is proposed under a common framework. Spectral efficiency, power spectral density, peak to average power ratio and performance in terms of bit error rate under various realistic channel conditions are assessed. The waveforms are then compared in an asynchronous multi-user uplink transmission. Based on these results, in order to increase the spectral efficiency, a bit loading algorithm is proposed to cope with the non-uniform distribution of the interference across the carriers. The benefits of these new waveforms for the foreseen 5G use cases are clearly highlighted. It is also stressed that some concepts still need to be improved to achieve the full range of expected benefits of 5G.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.004
      Issue No: Vol. 24 (2017)
  • High SNR approximation for performance analysis of two-way multiple relay
    • Authors: Muhammad I. Khalil; Stevan M. Berber; Kevin W. Sowerby
      Pages: 62 - 70
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Muhammad I. Khalil, Stevan M. Berber, Kevin W. Sowerby
      Signal-to-Noise Ratio (SNR) is the key parameter in the performance evaluation of Two-Way, Amplify-and-Forward, Multiple-Relaying (TAF-MR) networks. This paper introduces new methods that use high SNR (HSNR) level approximations to analyze accurately the Bit Error Rate (BER), optimize the Relay Location (RL), and balance the energy efficiency (EE) and spectral efficiency (SE) of such networks. We consider a flat-fading channel and a strategy for selecting a relay with the highest SNR. Standardized BER expressions are obtained for a wide range of SNRs (low, high, and optimal) to yield more accurate predictions of the BER performance. Thus, by using HSNR, a unified analysis for calculating the Asymptotic BER (ABER) and the exact BER (EBER) performance is developed. The optimal SNR level is obtained by optimizing the power of network sources, which include the relay and user powers. Further, we propose a method for integrating the RL with the balancing of the EE and SE optimally to achieve the best EE improvement. The derived expressions for the methods are validated by simulation.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.007
      Issue No: Vol. 24 (2017)
  • Power efficient and coordinated eICIC-CPC-ABS method for downlink in
           LTE-advanced heterogeneous networks
    • Authors: Srinivasa Rao K.; Vinay Kumar; Sudhir Kumar; Sadanand Yadav; Vinay Kumar Ancha; Rajeev Tripathi
      Pages: 71 - 82
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Srinivasa Rao K., Vinay Kumar, Sudhir Kumar, Sadanand Yadav, Vinay Kumar Ancha, Rajeev Tripathi
      In 2020, mobile data traffic is expected to be a thousand times more than the current scenario. In order to handle this increased capacity, improvement in spectral efficiency is one of the challenging task. In long term evolution (LTE) and long term evolution advanced (LTE-A), deployment of small cell base station (SBS) and hotspot are step to handle the increased capacity of the network and quality of service. In this scenario, the SBSs are deployed under the coverage of macro cell base station (MBS). Neighbour MBS and neighbour SBS create intra and inter-cell interference to the users in the overlapped region. In order to mitigate interference, coordination between base stations is required. In this paper, we propose an enhanced intercell interference coordination by considering centralized processing controller with almost blank subframe (eICIC-CPC-ABS) for heterogeneous networks (HetNets). Centralized processing controller (CPC) at MBS decides the radio resource allocation of each SBSs based on user location. The dynamic frequency and reduced transmission power depend on the user locations. The analytical and simulation results demonstrate that the proposed method (eICIC-CPC-ABS) provides higher signal to interference plus noise ratio (SINR) compared to existing models: inter cell interference coordination (ICIC) and enhanced inter cell interference coordination (eICIC). The proposed method provides significant savings in transmitting power. Additionally, it increases the network capacity and coverage.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.002
      Issue No: Vol. 24 (2017)
  • Adaptive and efficient nonlinear channel equalization for underwater
           acoustic communication
    • Authors: Dariush Kari; Nuri Denizcan Vanli; Suleyman S. Kozat
      Pages: 83 - 93
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Dariush Kari, Nuri Denizcan Vanli, Suleyman S. Kozat
      We investigate underwater acoustic (UWA) channel equalization and introduce hierarchical and adaptive nonlinear (piecewise linear) channel equalization algorithms that are highly efficient and provide significantly improved bit error rate (BER) performance. Due to the high complexity of conventional nonlinear equalizers and poor performance of linear ones, to equalize highly difficult underwater acoustic channels, we employ piecewise linear equalizers. However, in order to achieve the performance of the best piecewise linear model, we use a tree structure to hierarchically partition the space of the received signal. Furthermore, the equalization algorithm should be completely adaptive, since due to the highly non-stationary nature of the underwater medium, the optimal mean squared error (MSE) equalizer as well as the best piecewise linear equalizer changes in time. To this end, we introduce an adaptive piecewise linear equalization algorithm that not only adapts the linear equalizer at each region but also learns the complete hierarchical structure with a computational complexity only polynomial in the number of nodes of the tree. Furthermore, our algorithm is constructed to directly minimize the final squared error without introducing any ad-hoc parameters. We demonstrate the performance of our algorithms through highly realistic experiments performed on practical field data as well as accurately simulated underwater acoustic channels.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.001
      Issue No: Vol. 24 (2017)
  • Performance of lattice coset codes on Universal Software Radio Peripherals
    • Authors: Jinlong Lu; J. Harshan; Frédérique Oggier
      Pages: 94 - 102
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Jinlong Lu, J. Harshan, Frédérique Oggier
      We consider an experimental setup of three Universal Software Radio Peripherals (USRPs) that implement a wiretap channel, two USRPs are the legitimate players Alice and Bob, while the third USRP is the eavesdropper, whose position we vary to evaluate information leakage. The experimented channels are close to slow fading channels, and coset coding of lattice constellations is used for transmission, allowing to introduce controlled randomness at the transmitter. Simulation and measurement results show to which extent coset coding can provide confidentiality, as a function of Eve’s position, and the amount of randomness used.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.004
      Issue No: Vol. 24 (2017)
  • Decode-and-forward with quadrature spatial modulation in the presence of
           imperfect channel estimation
    • Authors: Raed Mesleh; Salama S. Ikki; Iyad Tumar; Sahel Alouneh
      Pages: 103 - 111
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Raed Mesleh, Salama S. Ikki, Iyad Tumar, Sahel Alouneh
      The performance of quadrature spatial modulation (QSM) multiple-input multiple-output (MIMO) system with cooperative decode and forward (DF) relays is analyzed in this paper. QSM is a new MIMO transmission technique that enhances the overall performance of conventional spatial modulation through exploiting quadrature spatial dimension. A practical scenario is considered where the channel is estimated at the relays and the destination and the impact of channel estimation error is investigated. Two cooperative systems are considered in the study. In the first system, multiple single-antenna DF relays are assumed, whereas, in the second system, single multiple-antennas DF relay is considered. For both systems, an analytical expression for the pair wise error probability (PEP) is obtained. As well, an asymptotic expression for the PEP at high and pragmatic signal to noise ratio is derived. Derived expressions are used to provide an upper bound on the average bit error ratio. The derived analysis is corroborated through Monte Carlo simulations and results demonstrate a close-match for a wide range of SNR values.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.005
      Issue No: Vol. 24 (2017)
  • Channel resource allocation and availability prediction in hybrid access
    • Authors: Muhammad Rehan Usman; Muhammad Arslan Usman; Soo Young Shin
      Pages: 112 - 122
      Abstract: Publication date: September 2017
      Source:Physical Communication, Volume 24
      Author(s): Muhammad Rehan Usman, Muhammad Arslan Usman, Soo Young Shin
      In this paper, three channel assignment models are proposed for channel resource allocation in femtocells. The models proposed are based on the Markov chain process. According to the access mechanisms in femtocells, the Third-Generation Partnership Project (3GPP) has described two kinds of users in the femtocell application; open users and the closed subscriber group (CSG). In hybrid access mechanism for femtocells, both CSG users and open users are usually referred as subscribers and non-subscribers respectively. So, in this work, for all the proposed models, the CSG and open users are categorized into two groups; the subscriber group (SG) and the non-subscriber group (NSG) respectively. The proposed models provide priority based channel resource allocation strategies between the SG and NSG. Furthermore, the focus of this research is to provide variable channel resource sharing among the SG and NSG to keep the wastage of channel resources minimum for better quality of service (QoS). The analysis is conducted in terms of channel resource blocking management for all the models and to validate the analysis, simulations are performed at the end of this paper. Further, channel resource blocking prediction, based on the blocking probability results for SG and NSG users, is also provided at the end. The prediction is done through risk analysis using the @ Risk tool. The simulations are provided in two parts; 1) the probability curves for SG and NSG against the total number of channels and 2) the risk analysis results for blocked channels prediction using the @ Risk tool.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.007
      Issue No: Vol. 24 (2017)
  • Effect of tunnel geometry and antenna parameters on through-the-air
           communication systems in underground mines: Survey and open research areas
    • Authors: Intikhab Hussain; Frederick Cawood; Rex van Olst
      Pages: 84 - 94
      Abstract: Publication date: Available online 10 March 2017
      Source:Physical Communication
      Author(s): Intikhab Hussain, Frederick Cawood, Rex van Olst
      In the mining industry, communication systems are important for ensuring personnel safety and optimizing the mining processes underground. The need for through-the-air (TTA) in the underground mining industry has been evolved from man-to-man, man-to-machine and machine-to-machine real-time voice, video and data transmission. Reliable communication has always been a challenge in the underground environment due to harsh and dynamic conditions. This article surveys the effect of tunnel geometry and antenna parameters on TTA communication system performance in underground mines. It provides a comprehensive review of measurement campaigns that have been published to date by systematic organization of literature. The open research areas for future investigation are also discussed. Finally, digital system ′ s findings in the University of Witwatersrand (WITS) mock-mine are presented.

      PubDate: 2017-03-13T02:56:33Z
      DOI: 10.1016/j.phycom.2017.03.002
      Issue No: Vol. 23 (2017)
  • Online AL-FEC policy problem on mobile unicast services
    • Authors: C. Bouras; N. Kanakis
      Pages: 95 - 102
      Abstract: Publication date: June 2017
      Source:Physical Communication, Volume 23
      Author(s): C. Bouras, N. Kanakis
      Forward error correction (FEC) is a method for error control of data transmission adopted in several mobile multicast standards. FEC is a feedback free error recovery method where the sender introduces redundant data in advance with the source data enabling the recipient to recover from different arbitrary packet losses. Recently, the adoption of FEC error control method has been boosted by the introduction of powerful Application Layer FEC (AL-FEC) codes, e.g. RaptorQ codes. Furthermore, several works have emerged aiming to address the shortcomings of AL-FEC protection application utilizing deterministic or randomized online algorithms to enhance the efficiency of AL-FEC error control method. In this work, since the investigation of AL-FEC application as primary or auxiliary error protection method over mobile multicast environments is a well investigated field but the opportunity of utilizing the AL-FEC over mobile unicast services as the only method for error control replacing common feedback based methods that are now considered to be obsolete, we provide an analysis on the feasibility of AL-FEC protection over unicast delivery utilizing online algorithms in conjunction with AL-FEC codes with exceptional recovery performance.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.03.003
      Issue No: Vol. 23 (2017)
  • Joint impact of nodes-mobility and channel estimation error on the
           performance of two-way relay systems
    • Authors: Ashish K. Meshram; Devendra S. Gurjar; Prabhat K. Upadhyay
      Pages: 103 - 113
      Abstract: Publication date: June 2017
      Source:Physical Communication, Volume 23
      Author(s): Ashish K. Meshram, Devendra S. Gurjar, Prabhat K. Upadhyay
      This paper presents the performance analysis of a two-way relay system with nodes-mobility (NM) and channel estimation errors (CEE) under time-varying Rayleigh fading. Herein, analog network coding protocol is employed at the relay node. All the participating nodes are half-duplex and equipped with single-antenna devices. Specifically, we utilize first-order Markovian model to characterize the impact of NM in the channel. Along with the NM, we also consider that the CEE may exist in practical scenarios, where nodes require to estimate the channel state information. By incorporating these factors, we first derive the instantaneous end-to-end (e2e) signal-to-noise ratios (SNRs) at two source nodes. Then, we obtain the exact closed-form expressions for distribution and density functions of the two e2e SNRs. After that, we derive the accurate expressions of various performance metrics, viz., sum-bit error rate, overall outage probability, and ergodic sum-rate. Further, to attain more insights into the considered system, we deduce the asymptotic behavior of these performance metrics. Finally, numerical and Monte-Carlo simulation results are provided to validate our theoretical analysis and to illustrate the impact of NM and CEE on the performance measures of the considered system.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.03.004
      Issue No: Vol. 23 (2017)
  • A family of sparse group Lasso RLS algorithms with adaptive regularization
           parameters for adaptive decision feedback equalizer in the underwater
           acoustic communication system
    • Authors: Lu Liu; Dajun Sun; Youwen Zhang
      Pages: 114 - 124
      Abstract: Publication date: June 2017
      Source:Physical Communication, Volume 23
      Author(s): Lu Liu, Dajun Sun, Youwen Zhang
      In this paper, we propose a family of sparse group Lasso (least absolute shrinkage and selection operator) Recursive Least Squares (RLS) algorithms for sparse underwater acoustic channel equalization. The proposed adaptive RLS algorithms employ a family of mixed norms, such as l 1 l 2 , 1 -norm, l 1 l ∞ , 1 -norm, l 1 l 2 , 0 -norm, l 1 l 1 , 0 -norm, l 0 l 2 , 1 -norm, l 0 l ∞ , 1 -norm, l 0 l 2 , 0 -norm, and l 0 l 1 , 0 -norm, as the sparsity constraint in the penalty function to exploit the sparsity of the underwater acoustic communication system. The proposed adaptive RLS algorithms can adaptively select the regularization parameters regardless of whether the channel of underwater acoustic channel is general sparse channel, group sparse channel or the mixed sparse channel consisting of general sparse channel and group sparse channel. Moreover, this paper presents a direct adaptive decision feedback equalizer (DA-DFE) that exploits any sparse channel structure with the proposed adaptive RLS algorithms in the lake and sea experiments. Experimental results verify that the DA-DFE receiver with the proposed family of sparse group Lasso RLS algorithms can achieve a better performance in terms of convergence rate, mean square deviation (MSD) and symbol error rate (SER) in the single-input single-output (SISO) single carrier underwater acoustic communication system.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.03.005
      Issue No: Vol. 23 (2017)
  • Joint signal alignment precoding and physical network coding for
           heterogeneous networks
    • Authors: Syed Saqlain Ali; Daniel Castanheira; Adão Silva; Atílio Gameiro
      Pages: 125 - 133
      Abstract: Publication date: June 2017
      Source:Physical Communication, Volume 23
      Author(s): Syed Saqlain Ali, Daniel Castanheira, Adão Silva, Atílio Gameiro
      Mobile traffic in cellular based networks is increasing exponentially, mainly due to the use of data intensive services like video. One effective way to cope with these demands is to reduce the cell-size by deploying small-cells along the coverage area of the current macro-cell system. The deployment of small-cells significantly improves the indoor coverage. Nevertheless, as additional spectrum licenses are difficult and expensive to acquire, it is expected that the macro and small-cells will coexist under the same spectrum. The coexistence of the two systems results in cross-tier/inter-system interference. In this context, we consider the application of joint signal alignment (SA) and physical network coding (PNC) for the uplink of heterogeneous networks, in order to cancel the interference generated from small-cells at the macro-cell user terminal. The joint design of SA and PNC allows to serve more users than the case where only PNC or interference alignment (IA) is employed individually. We compare our proposed joint SA-PNC schemes with the recently designed IA based techniques for the uplink heterogeneous systems. Simulation results show that the proposed SA-PNC is quite efficient to remove the inter-tier/system interference while allowing to increase the overall data rate, by serving more users, as compared with the IA based methods

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.03.006
      Issue No: Vol. 23 (2017)
  • Editorial for Physical Communication Journal 2016
    • Authors: Ian F. Akyildiz
      Abstract: Publication date: March 2017
      Source:Physical Communication, Volume 22
      Author(s): Ian F. Akyildiz

      PubDate: 2017-02-18T02:34:38Z
      DOI: 10.1016/s1874-4907(17)30037-x
      Issue No: Vol. 22 (2017)
  • Spectrum sensing for OFDM signals using pilot induced cyclostationarity
           in the presence of cyclic frequency offset
    • Authors: Ribhu Chopra; Debashis Ghosh; D.K. Mehra
      Abstract: Publication date: Available online 1 August 2017
      Source:Physical Communication
      Author(s): Ribhu Chopra, Debashis Ghosh, D.K. Mehra
      In this paper, the problem of spectrum sensing of OFDM signals for cognitive radios is considered. It is proposed to detect the cyclostationary features introduced in an OFDM signal due to inter-pilot correlation. The performance of the proposed detector is derived and verified in case of AWGN channels. It is observed that the performance of cyclostationary detectors relies on the knowledge of the exact value of the cyclic frequency of the signal of interest. However, an offset in the cyclic frequency may arise due to several reasons. Therefore, for the proposed detector to perform reliably, there is a need to estimate the cyclic frequency offset. The Cramer-Rao bound for the cyclic frequency offset (CFO) estimator is derived, and based on it, two algorithms to estimate and compensate for the CFO are proposed. Simulation results are then used to study the performance of the proposed detection technique under Rayleigh fading both in the presence and the absence of CFO. The performance of the proposed system model is also studied under fast fading, and an alternative test statistic is proposed.

      PubDate: 2017-08-03T17:48:59Z
      DOI: 10.1016/j.phycom.2017.07.008
  • Carrier to interference ratio, rate and coverage analysis in shotgun
           cellular systems over composite fading channels
    • Authors: Asma Bagheri; Ghosheh Abed Hodtani
      Abstract: Publication date: Available online 31 July 2017
      Source:Physical Communication
      Author(s): Asma Bagheri, Ghosheh Abed Hodtani
      Wireless communication performance in shotgun cellular system (SCS: wireless communication system with randomly placed base stations) is analysed. Aiming at this analysis, (i) the carrier to interference ratio (CIR), as an important measure in a cellular network, is considered in the downlink (path-loss, shadowing and multi-path) fading channel. Since direct calculating of the distribution of CIR is complicated, a related mathematical equation is determined through which the probability density function (PDF) of CIR can be calculated. And then, as a special case, the tail probability of CIR is obtained. (ii) A normal approximation for inverse of CIR is proposed which is applicable for calculating a tractable PDF for the downlink CIR. The analytically calculated and the approximate PDFs of CIR are compared with numerical PDFs. (iii) The distribution of the downlink rate and a lower bound for the average rate; the analytical expression for coverage of a user in an SCS based on its received CIR, and an average value for coverage are calculated. (iv) Simulation results show that the closed form and approximate PDFs over different models are close to numerical ones.

      PubDate: 2017-08-03T17:48:59Z
      DOI: 10.1016/j.phycom.2017.07.005
  • Spectrum efficient power allocation schemes for OFDM cognitive radio with
           statistical interference constraints
    • Authors: Manoranjan Rai Bharti; Debashis Ghosh
      Abstract: Publication date: Available online 26 July 2017
      Source:Physical Communication
      Author(s): Manoranjan Rai Bharti, Debashis Ghosh
      In this paper, we study the power allocation problem for an orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) system. In a departure from the conventional power allocation schemes available in the literature for OFDM-based CR, we propose power allocation schemes that are augmented with spectral shaping. Active interference cancellation (AIC) is an effective spectral shaping technique for OFDM-based systems. Therefore, in particular, we propose AIC-based optimal and suboptimal power allocation schemes that aim to maximize the downlink transmission capacity of an OFDM-based CR system operating opportunistically within the licensed primary users (PUs) radio spectrum in an overlay approach. Since the CR transmitter may not have the perfect knowledge about the instantaneous channel quality between itself and the active PUs, the interference constraints imposed by each of the PUs are met in a statistical sense. We also study an optimal power allocation scheme that is augmented with raised cosine (RC) windowing-based spectral shaping. For a given power budget at the CR transmitter and the prescribed statistical interference constraints by the PUs, we demonstrate that although the on-the-run computational complexity of the proposed AIC-based optimal power allocation scheme is relatively higher, it may yield better transmission rate for the CR user compared to the RC windowing-based power allocation scheme. Further, the AIC-based suboptimal scheme has the least on-the-run computational complexity, and still may deliver performance that is comparable to that of the RC windowing-based power allocation scheme. The presented simulation results also show that both the AIC-based as well as the RC windowing-based power allocation schemes lead to significantly higher transmission rates for the CR user compared to the conventional (without any spectral shaping) optimal power allocation scheme.

      PubDate: 2017-08-03T17:48:59Z
      DOI: 10.1016/j.phycom.2017.07.003
  • ScOFi: Schematic assisted optimum fingerprinting for Wi-Fi indoor
           localization using peer hand-shake
    • Authors: Mu Zhou; Arigye Wilford; Zengshan Tian; Qiao Zhang
      Abstract: Publication date: Available online 25 July 2017
      Source:Physical Communication
      Author(s): Mu Zhou, Arigye Wilford, Zengshan Tian, Qiao Zhang
      Received signal strength fingerprints based on Wi-Fi spectrum have been widely adopted in the recent years for indoor localization purposes due to cost-effectiveness and availability. However, until the peer hand-shake (PHS), existing work had not constrained the schematic dimension of the target area, which could dramatically reduce the localization error. As the demand for sensors everywhere schemes for 5G networks keeps on booming, effective signal propagation characterization with in indoors is very essential for Internet of things (IoT) indoor localization and navigation applications. We review, extend the validation of the PHS technique that leverages the schematic dimensions of the target area within the total indoor environment to construct, auto-dynamically transform and update fingerprint in complex indoor environments. Extensive experimental validation has been carried out in two scenarios; Scenario 1 categorizes lobby area while Scenario 2 categorizes corridor areas. We analyze the accuracy performance using Nearest Neighbor (NN) and the KNN algorithms. Experimental results show robustness of the PHS, achieving lower average localization error in diverse indoor dimensionalities than comparisons.

      PubDate: 2017-08-03T17:48:59Z
      DOI: 10.1016/j.phycom.2017.06.013
  • Performance evaluation of cognitive underlay multi-hop networks with
           interference constraint in Rayleigh fading channels perturbed by
           non-Gaussian noise
    • Authors: Osamah S. Badarneh; Fares S. Almehmadi; Taimour Aldalgamouni
      Abstract: Publication date: Available online 17 July 2017
      Source:Physical Communication
      Author(s): Osamah S. Badarneh, Fares S. Almehmadi, Taimour Aldalgamouni
      In this paper, the performance of regenerative decode-and-forward (DaF) cognitive multi-hop underlay networks over independent but non-identically distributed (i.n.i.d.) Rayleigh fading channels with additive white generalized Gaussian noise (AWGGN) is analyzed. Precisely, we derive exact analytical expressions for the average bit error rate (BER) of M -ary quadrature amplitude modulation ( M -QAM) and M -ary phase shift keying ( M -PSK). Besides, an exact expression for the average symbol error rate (SER) of M -QAM is obtained. In addition, lower- and upper-bound expressions for the end-to-end ergodic capacity is provided. Some representative numerical examples are presented to study the impact of the noise shaping parameter and average power of the interfering and secondary links on the system performance. Our obtained analytical results are supported with Monte-Carlo simulations to validate the accuracy of the analytical derivations.

      PubDate: 2017-07-24T13:45:22Z
      DOI: 10.1016/j.phycom.2017.06.009
  • Power allocation for multi-user OFDM-DCSK system in frequency selective
           fading channel
    • Authors: Majid Mobini; Mohammad Reza Zahabi
      Abstract: Publication date: Available online 16 July 2017
      Source:Physical Communication
      Author(s): Majid Mobini, Mohammad Reza Zahabi
      In this paper, we introduce a grouping approach for power allocation in the multi-user OFDM-DCSK (MU-OFDM-DCSK) system under the frequency selective fading channels. The suggested procedure is convenient also for the other comb-type non-coherent schemes with similar structure. Furthermore, we derive analytical bit error rate (BER) expression for the grouped scheme and offer an optimal power distribution policy for both the single- and multi-user scenarios. This power assignment strategy is formulated by a min-max problem with the target of the worst group BER minimization incorporating total power and interference constraints. Simulation results confirm the advantages of the proposed power allocation scheme.

      PubDate: 2017-07-24T13:45:22Z
      DOI: 10.1016/j.phycom.2017.07.002
  • On signal space diversity: An adaptive interleaver for enhancing physical
           layer security in frequency selective fading channels
    • Authors: Marwan Yusuf; Hüseyin Arslan
      Abstract: Publication date: Available online 16 July 2017
      Source:Physical Communication
      Author(s): Marwan Yusuf, Hüseyin Arslan
      Signal space diversity is a powerful technique that increases reliability of detection over fading channels. In this paper, we explore the ability of this technique to provide secure communication. We enhance the security of OFDM systems in frequency selective fading channels by providing more diversity gain to the legitimate user compared to an eavesdropper. This is done by adapting the interleaving pattern to the channel of the legitimate user in rich multipath environments, where spatially separated channels are typically independent to each other. This ensures secrecy in a time division duplex system, where the eavesdropper has no information regarding the channel of the legitimate user. The scheme can also be used in the conventional frequency division duplex system, which is more challenging in terms of security aspects because of the channel state information leakage. A theoretical analysis is presented on the bit-error probability in Rayleigh fading environment. The numerical results support the conclusion that adapting the interleaving pattern to the CSI of the legitimate user provides a gain in the bit-error rate performance over the eavesdropper.

      PubDate: 2017-07-24T13:45:22Z
      DOI: 10.1016/j.phycom.2017.07.001
  • Intra-group principal modes in graded-index multimode fibers used for mode
           group division multiplexing transmission
    • Authors: Jiawei Han; Caifeng Qu
      Abstract: Publication date: Available online 12 July 2017
      Source:Physical Communication
      Author(s): Jiawei Han, Caifeng Qu
      By considering very strong intra-group mixing while neglecting inter-group mixing in mode group division multiplexing (MGDM) transmission, we theoretically introduce and describe the physical model of intra-group principal modes (IGPMs) in graded-index (GI) multimode fibers (MMFs), from the view of fiber transmission matrices for both cases of one- and dual-polarization. Proof-of-concept numerical calculations for an exemplary mode-group-channel with the two lowest-order degenerate mode groups (namely the three lowest-order fiber eigenmodes) show that IGPMs can exhibit potential possibilities of the MGDM channel with minimal mode mixing/dispersion-induced signal distortion over a GI MMF.

      PubDate: 2017-07-24T13:45:22Z
      DOI: 10.1016/j.phycom.2017.06.011
  • An adaptive step-size spectrum auction mechanism for two-tier
           heterogeneous networks
    • Authors: Feng Zhao; Zhenyu Tan; Hongbin Chen
      Abstract: Publication date: Available online 12 July 2017
      Source:Physical Communication
      Author(s): Feng Zhao, Zhenyu Tan, Hongbin Chen
      Recently, with the rapid growth of demands for wireless communications, dynamic spectrum allocation is one of the key technologies in cognitive radio networks to resolve the realistic problem of low utilization efficiency of spectrum. It mainly focuses on how the spectrum owner dynamically allocates idle spectrum to secondary users who have no licensed spectrum for communications. In this paper, a dynamic spectrum allocation model based on auction theory in a two-tier heterogeneous network is proposed, in which the primary users (PUs) are the sellers, the central processor (CP) auctioneer is the coordinator, and femtocell base station (FBS) as the buyer bids for the idle spectrum and act as a wireless access point that provides communication services for secondary users (SUs). Its basic process is as follows: the auctioneer gradually raises the spectrum price from the reserved price; each bidder decides whether participates in the purchase or not. It is characterized by distributed execution and low complexity which can reduce unnecessary information exchange between primary users or secondary users. Meanwhile it can enhance the utilization of spectrum and improve the efficiency of the auction by generate the incentive mechanism.

      PubDate: 2017-07-24T13:45:22Z
      DOI: 10.1016/j.phycom.2017.06.012
  • Learning automata-based algorithms for solving the stochastic shortest
           path routing problems in 5G wireless communication
    • Authors: Ying Guo; Shenghong Li; Wen Jiang; Bo Zhang; Yinghua Ma
      Abstract: Publication date: Available online 11 July 2017
      Source:Physical Communication
      Author(s): Ying Guo, Shenghong Li, Wen Jiang, Bo Zhang, Yinghua Ma
      Stochastic Shortest Path Routing (SSPR) problem has always been a critical topic in communication area, especially after a boom in the 5G wireless communication emerges. In this paper, we consider the SSPR problem in a network, where the context is a dynamic, and simultaneously the probability distribution of the constantly changing edges is unknown beforehand. A hierarchical structurized learning automata applied to SSPR, namely SSPR-hieraStructure L R I , is proposed to solve the issue, providing a novel way to pick out the shortest path from source to destination in a stochastic graph. Two kinds of LA prototypes, i.e, variable action learning automata and hierarchical system of learning automata are assembled to exert their respective strengths, based on which we further makes adequate use of a hierarchical structure for modeling. The innovation lies in a convergence by layer rather than as a whole, thus determining the shortest path is converted to searching an optimal node in each layer. Moreover, the searching space is largely reduced by structural pruning, for the purpose of speeding up the algorithm progress. The experimental results involving various aspects demonstrate the effectiveness and efficiency of the proposed algorithm, which outperforms the state of arts in LA based SSPR problems, with a higher accuracy rate, a faster convergence speed, a lower sampling consumption but a higher sampling efficiency.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.010
  • Transmit power and bits/channel use adaption in competitive cognitive
           radio networks
    • Authors: Lutfa Akter; Neelanjana Subin Ferdous; Zobaer Ahmed
      Abstract: Publication date: Available online 11 July 2017
      Source:Physical Communication
      Author(s): Lutfa Akter, Neelanjana Subin Ferdous, Zobaer Ahmed
      In this paper, we propose an optimization framework to determine the distribution of power and bits/channel use to secondary users in a competitive cognitive radio networks. The objectives of the optimization framework are to minimize total transmission power, maximize total bits/channel use and also to maintain quality of service. An upper bound on probability of bit error and lower bound on bits/channel use requirement of secondary users are considered as quality of service. The optimization problem is also constrained by total power budget across channels for a user. Simulating the framework in a centralized manner shows that more transmit power is allocated in a channel with higher noise power and bits/channel use is directly proportional to signal to interference plus noise power ratio. The proposed framework is more capable of supporting high bits/channel use requirement than existing resource allocation framework. We also develop the game theoretic user based distributed approach of the proposed framework. We see that user based distributed solution also follows centralized solution.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.008
  • Determination of the best carrier frequency based on the system and
           environmental parameters in underwater acoustic systems
    • Authors: Abdollah Doosti-Aref; Ataollah Ebrahimzadeh
      Abstract: Publication date: Available online 5 July 2017
      Source:Physical Communication
      Author(s): Abdollah Doosti-Aref, Ataollah Ebrahimzadeh
      One of the most challenging features of underwater acoustic (UWA) channel in comparison with its terrestrial radio frequency counterpart is highly frequency-dependent path loss. Thus, utilizing efficient carrier frequencies in UWA systems can considerably reduce the path loss. In this context, this paper presents an approximate formula for determining the best carrier frequency based on both the system and environmental parameters. To achieve this goal, this research first addresses a simple algorithm including general steps for tuning the parameters of Francois and Garrison (FG) formula in the frequency range of 10 to 100 kHz based on the appropriate experimental data which can be acquired from any interest region. Second, for a more accurate modeling of path loss, this paper considers the loss due to the reflections of sound from both the rough surface and bottom of the sea by employing the ray theory. Third, this study presents a general algorithm for modification of the power spectral density (PSD) of ambient noise based on Wenz formula in the frequency range of 10 to 100 kHz and the required experimental measurements which can be simply collected from any interest channel. Moreover, it is mathematically demonstrated that the ambient noise in the frequency range of 10 to 100 kHz, can be generally approximated with a strict sense stationary (SSS) colored normal stochastic process which is ergodic not only in mean and covariance but also in distribution. Finally, an approximate formula for the best carrier frequency is derived by maximizing the sound to noise intensity ratio (SNR). To verify the validity of simplifications and approximations utilized in this study and to assess the performance of our proposed algorithms and formulas, experimental results obtained in the Strait of Hormuz (SoH) are compared with the original, simplified, and modified models under different scenarios.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.006
  • Using artificial bee colony algorithm with crossover for power allocation
           in cognitive MIMO-OFDM system
    • Authors: Xin Zhang; Xiu Zhang
      Abstract: Publication date: Available online 29 June 2017
      Source:Physical Communication
      Author(s): Xin Zhang, Xiu Zhang
      Artificial bee colony (ABC) algorithm builds on simulating the intelligent behavior of honey bees. It shows good performance in many applications. As standard ABC algorithm does not employ any crossover operator, the dispersal of good genetic information amongst the solutions is undermined. In this paper, the impact of crossover operators on the performance of ABC is studied. Eight crossover operators, representing all kinds of crossover operators, are used in this study. A trial and error method is used to detect the most proper crossover operator and crossover rate for incorporation into the ABC algorithm on mathematical functions as an initial attempt. The overall best configuration of ABC with crossover which has been identified is then applied to solve power allocation problem in cognitive multiple input and multiple output orthogonal frequency division multiplexing (MIMO-OFDM) cognitive system. Promising performances are obtained when compared with those from genetic algorithm, particle swarm optimization and differential evolution algorithm.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.003
  • Circular antenna design by adaptive position inheritance artificial bee
           colony algorithm
    • Authors: Xin Zhang; Xiu Zhang
      Abstract: Publication date: Available online 15 June 2017
      Source:Physical Communication
      Author(s): Xin Zhang, Xiu Zhang
      Reliable communication is a key factor in the development of the fifth generation wireless communication systems. To achieve reliable communication, designing desirable antenna arrays is the basis so as to realize wireless data transmission. Artificial bee colony (ABC) algorithm has shown its powerfulness in engineering design problems, though the performance of ABC could be improved further through information exchange of existing solutions. This paper proposes an adaptive position inheritance strategy for ABC algorithm. It adaptively decides the number of positions to be inherited attached with the evolutionary process of the algorithm. Take circular antenna as design example. The proposed algorithm is tested against with method of exhaustion. Simulation results show the usefulness of the proposed algorithm. Moreover, the proposed algorithm is also compared with state of the art algorithm under ABC paradigm. It turns out that the proposed algorithm attains better design solution. Thus, the proposed algorithm is useful for providing good design solutions in reliable communication.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.004
  • A simplified massive MIMO implemented with pre or post-processing
    • Authors: Mário Marques da Silva; Rui Dinis
      Abstract: Publication date: Available online 15 June 2017
      Source:Physical Communication
      Author(s): Mário Marques da Silva, Rui Dinis
      This paper considers the use of massive multiple input, multiple output (MIMO) combined with single-carrier with frequency-domain equalization (SC-FDE) modulations, associated to millimeter wave (mm-Wave) communications using precoding. For the sake of comparison, this paper performs a comparison of pre and post-processing methodology, using the same algorithms. In this paper, we consider three different types of algorithms: Zero Forcing Transmitter (ZFT), Maximum Ratio Transmitter (MRT), and Equal Gain Transmitter (EGT), both of the latter two with iterative detection schemes. The advantage of both MRT and EGT relies on avoiding the computation of pseudo-inverse of matrices. The performance of MRT and EGT are very close to the matched filter bound just after a few iterations of a new proposed interference cancellation, even when the number of receiving antennas is not very high.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.06.002
  • On the security of K-tier heterogeneous cellular networks
    • Authors: Zhihao Zhong; Wenyu Luo; Jianhua Peng; Liang Jin
      Abstract: Publication date: Available online 2 June 2017
      Source:Physical Communication
      Author(s): Zhihao Zhong, Wenyu Luo, Jianhua Peng, Liang Jin
      Motivated by recent developments in heterogeneous cellular networks and physical-layer security, we aim to characterize the fundamental limits of secure communication in networks. Based on a general model in which both transmitters and receivers are randomly scattered in space, we model the locations of K-tier base stations, users, and potential eavesdroppers as independent two-dimensional Poisson point processes. Using the proposed model, we analyze the achievable secrecy rates for an arbitrarily located mobile user. Assuming that the cell selection is based on achievable-secrecy-rate threshold, we obtain approximations for: (a) secrecy coverage probability and (b) average secrecy load per tier. We also investigate how the network performance is affected by secrecy rate threshold, eavesdropper density, and different access strategies are analyzed, respectively. Finally, our theoretical claims are confirmed by the numerical results.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.005
  • A cooperative modulation recognition: New paradigm for power line networks
           in smart grid
    • Authors: Hai Yu; Liuqiang Shi; Yuwen Qian; Feng Shu; Jun Li; Yixueying Zhao; Dushantha Nalin K. Jayakody
      Abstract: Publication date: Available online 31 May 2017
      Source:Physical Communication
      Author(s): Hai Yu, Liuqiang Shi, Yuwen Qian, Feng Shu, Jun Li, Yixueying Zhao, Dushantha Nalin K. Jayakody
      Power Line communication (PLC) is an attractive approach to provide information transfer services for future smart grids. However, since various modulations are adopted, it is a great challenge to add new nodes to collect the data from the devices or sensors in in-home PLC networks. In this paper, we propose an approach to automatically access to the PLC network by identifying the modulation of signals. To improve the correct recognition rate on identification of modulations, we propose a multiple input and multiple output (MIMO) based cooperative modulation identification scheme. After receiving the recognition results from accessing nodes, the central server makes the comprehensive and accurate recognition decision on the modulation of the PLC network. Furthermore, the fourth-order cumulants for multiple users are adopted as the feature for this modulation classifier. With the feature, we propose an improved modulation classification algorithm based on the maximum likelihood. Simulations show that a high detection rate and low false positive rate can be achieved as we employ the cooperative modulation identifying scheme and the improved recognition algorithm.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.05.006
  • Multi-level quantization and blind equalization based direct transmission
           method of digital baseband signal
    • Authors: Maolin Ji; Jin Chen; Zeng Liu; Ying Tong; Fajie Duan; Tariq S. Durrani; Jiajia Jiang
      Abstract: Publication date: Available online 10 May 2017
      Source:Physical Communication
      Author(s): Maolin Ji, Jin Chen, Zeng Liu, Ying Tong, Fajie Duan, Tariq S. Durrani, Jiajia Jiang
      The direct transmission of digital baseband signals has practical significance in the field of Ethernet terminal connection, high-speed digital communication, data transmission of various types of information peripherals. The signal amplitude gradually decays while the transmission distance increases. Also the attenuation is proportional to the signal frequency, resulting in signal distortion and receiving error. It is a common method for digital baseband signal transmission to use pre-emphasis chip and equalizer chip to improve the transmission quality with a wide range of mature applications. This paper describes a new type of digital signal transmission method, as the receiver using analog-to-digital converter, instead of equalizer chip, to achieve the multi-level quantization of receiving time-domain data waveform. The waveform of the transmitted digital high and low level signal is sampled into multi-bit values. Then, the paper realizes adaptive frequency domain equalization based on soft threshold and makes use of multi-level quantization soft information for error correction. Error correcting code is mainly used to correct the error caused by the channel bandwidth limit, external noise or interference in the process of data transmission, so as to improve the stability and reliability of the transmission. The paper uses the two-stage error correcting codec system based on both Turbo and BCH coding, to achieve the high performance of Turbo code, and good characters of respond time and complexity. The transmitter outputs 12.5 MHz pseudo-random sequence through a 199.93 meter unshielded balanced twisted pair transmission medium. And the receiver circuit using a 62.5MSPS analog-to-digital converter over-samples the waveform to 8-level quantity. The output error of a 65536 bit pseudo-random sequence is less than 8 bits, and the error correction can be further improved by 8b-10b codec. Compared with the traditional pre-emphasis and balanced interface ICs connection, the method described in this article has the advantages of longer transmission distance, better flexibility and wider scope of use.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.008
  • Leakage-based beamforming via game theory for reverse spectrum auction in
           cellular offloading systems
    • Authors: Feng Zhao; Xiaofei Xu; Hongbin Chen
      Abstract: Publication date: Available online 21 April 2017
      Source:Physical Communication
      Author(s): Feng Zhao, Xiaofei Xu, Hongbin Chen
      The explosion of mobile traffic and highly dynamic property often make it increasingly stressful for a cellular service provider to provide sufficient cellular spectrum resources to support the dynamic change of traffic demand in a day. In this paper, considering the dynamic characteristic of the cellular network traffic demand, we not only proposed an optimal, truthful reverse auction incentive framework, but also proposed a valuation function which is based on third-party access points’ capacity. We consider spectrum sharing in a third-party network where several secondary users (SUs) share spectrum with a primary user (PU). A leakage-based beamforming algorithm is proposed via game theory to maximize the sum utility of third-party access points subject to the signal-to-leakage-and-noise (SLNR) constraint of SUs and PU interference constraint. The sum throughput maximization problem is formulated as a non-cooperative game, where the SUs compete with each other over the resources. Nash equilibrium is considered as the solution of this game. Simulation results show that the proposed algorithm can achieve a high sum throughput and converge to a locally optimal beamforming vector.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.006
  • Performance analysis of a novel 5G architecture via Content-Centric
    • Authors: Zhuo Li; Yankai Liu; Yutong Chen; Yaping Xu; Kaihua Liu
      Abstract: Publication date: Available online 21 April 2017
      Source:Physical Communication
      Author(s): Zhuo Li, Yankai Liu, Yutong Chen, Yaping Xu, Kaihua Liu
      Content-Centric Networking (CCN) is a recent paradigm conceived for future Internet architectures, where communications are driven by contents instead of host addresses. It binds the storage capacity into the network by using the in-network caching, which can reduce the transmission delay in the network. In this paper, a novel architecture of 5G via CCN, named as CCN-5G, is proposed. Meanwhile, the performance of CCN-5G are tested in the high-speed mobile environment. The simulation results show that the CCN-5G can achieve excellent performance and satisfy the future requirements of 5G.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.002
  • Auction-based spectrum allocation for CoMP systems utilizing hybrid
           division duplex
    • Authors: Feng Zhao; Yantao Miao; Hongbin Chen
      Abstract: Publication date: Available online 18 April 2017
      Source:Physical Communication
      Author(s): Feng Zhao, Yantao Miao, Hongbin Chen
      The coordinated multi-point (CoMP) transmission is a well-recognized promising technique for achieving high spectral efficiency. In this paper, we study the performance of the spectrum allocation and the system utility of the CoMP systems. First, we combine the hybrid division duplex (HDD) with a CoMP system to form a CoMP–HDD system, for the purpose of guaranteeing the quality demand of the channel state information (CSI) feedback. Second, in order to improve the system utility and the spectrum allocation efficiency of the CoMP–HDD system, we utilize the auction theory for the spectrum allocation. A system utility maximization problem is formulated as an NP-hard problem. Finally, we propose a multi-band multi-winner (MBMW) greedy algorithm to optimize the system utility and the spectrum allocation efficiency. Our simulation results demonstrate the effectiveness of the proposed algorithm.

      PubDate: 2017-07-12T09:52:57Z
      DOI: 10.1016/j.phycom.2017.04.003
  • Average symbol error rate and outage probability of DS-CDMA systems with
           AF relaying over asymmetric fading channels
    • Authors: Nuri Kapucu; Mehmet Bilim; Ibrahim Develi
      Abstract: Publication date: Available online 3 March 2017
      Source:Physical Communication
      Author(s): Nuri Kapucu, Mehmet Bilim, Ibrahim Develi
      In this paper, approximate outage probability (OP) and average symbol error rate (SER) of cooperative direct-sequence code-division multiple access (DS-CDMA) systems with amplify-and-forward (AF) relaying are evaluated over asymmetric fading channels. Practically, the channels between source ( S ) , relay ( R ) and destination ( D ) nodes in a DS-CDMA system can be subject to different fading due to the nature of wireless medium. Motivated by this reality, the S – D path is assumed to be Nakagami- m distributed which is a general fading model for different types of channel conditions while S – R and R – D paths are considered to experience Rician fading in order to include line of sight conditions. First, closed-form solutions are obtained for both the cumulative distribution function and the probability density function of S – R – D paths. Then, a closed-form total moment generating function (MGF) of the considered system is derived. The lower bound of the OP is calculated with the help of the inverse Laplace transform of the derived MGF expression while average SER is analyzed by evaluating the integral over the derived MGF. Finally, an asymptotic MGF expression is proposed for high signal-to-noise ratio (SNR) analysis of AF DS-CDMA systems. The simulation results are provided to verify the correctness of the analytical derivations. It is shown that the approximate OP and average SER results are in well agreement with the simulations and the asymptotic results are tight from medium to high SNR regime.

      PubDate: 2017-03-04T06:07:03Z
      DOI: 10.1016/j.phycom.2017.03.001
  • Distributed spatial modulation with dynamic frequency allocation
    • Authors: Kunal Sankhe; Sachin Chaudhari; Garimella Rama Murthy
      Abstract: Publication date: Available online 2 March 2017
      Source:Physical Communication
      Author(s): Kunal Sankhe, Sachin Chaudhari, Garimella Rama Murthy
      This paper proposes a distributed implementation of spatial modulation (SM) using cognitive radios. In distributed spatial modulation (DSM), multiple relays form a virtual antenna array and assist a source to transmit its information to a destination. The source broadcasts its signal, which is independently demodulated by all the relys. Each of the relays then divides the received data in two parts: the first part is used to decide which one of the relays will be active, and the other part decides what data it will transmit to the destination. An analytical expression for symbol error probability is derived for DSM in independent and identically distributed (i.i.d.) Rayleigh fading channels. The analytical results are later compared with Monte Carlo simulations. Further, an instantaneous symbol error rate (SER) based selection combining is proposed to incorporate the direct link between the source and destination with existing DSM. Next, DSM implementation is extended to a cognitive network scenario where the source, relays, and destination are all cognitive radios. A dynamic frequency allocation scheme is proposed to improve the performance of DSM in this scenario. The frequency allocation is modeled through a bipartite graph with end-to-end SER as a weight function. The optimal frequency allocation problem is formulated as minimum weight perfect matching problem and is solved using the Hungarian method. Finally, numerical results are provided to illustrate the efficacy of the proposed scheme.

      PubDate: 2017-03-04T06:07:03Z
      DOI: 10.1016/j.phycom.2017.02.005
  • Indoor cognitive radio operation within the broadcast TV protection
    • Authors: Meng-Jung Ho; Stevan M. Berber; Kevin W. Sowerby
      Abstract: Publication date: Available online 1 March 2017
      Source:Physical Communication
      Author(s): Meng-Jung Ho, Stevan M. Berber, Kevin W. Sowerby
      Although the broadcast television (TV) spectrum is currently open for unlicensed operation in the USA, a considerably large geographic area still remains excluded from the unlicensed operation due to potential interference to the licensed users. However, it might be possible to reuse primary spectrum within the protection contour if the frequency reuse occurs inside a building that shields radio signals and reduces interference to the primary system. Interference to outdoor licensed users from the indoor operations can be minimized if the unlicensed users adjust their transmit power according to their locations in the building. This paper presents an analysis and effectiveness evaluation of a novel cognitive radio (CR) system which enables CRs to access the licensed spectrum inside a building in the area within the protection contour. The system utilizes an indoor sensor network for (i) interference sensing, (ii) CR transmit power control, to limit the interference to the outdoor primary receiving antennas. Power control model of the indoor system has been developed to estimate safe transmit power for the indoor users. Two cases have been considered; single-user single-sensor (single indoor user and single sensor), and multi-user multi-sensor. Based on the power control model, a power control algorithm has been developed and its effectiveness is assessed through simulations. The algorithm is effective in realistic propagation scenarios, e.g. when internal partition walls and multipath fading are present. The outage probabilities in these propagation scenarios are found and the procedure of determining the transmit powers for CRs is presented.

      PubDate: 2017-03-04T06:07:03Z
      DOI: 10.1016/j.phycom.2017.02.006
  • MIMO-OFDM underwater acoustic communication systems–A review
    • Authors: Gang Qiao; Zeeshan Babar; Lu Ma; Songzuo Liu; Jinqiu Wu
      Abstract: Publication date: Available online 1 March 2017
      Source:Physical Communication
      Author(s): Gang Qiao, Zeeshan Babar, Lu Ma, Songzuo Liu, Jinqiu Wu
      The ever increasing demand for bandwidth, efficiency, spatial diversity and performance of underwater acoustic (UWA) communication has opened doors for the use of Multi-Input Multi-Output (MIMO). A combination of MIMO and Orthogonal Frequency Division Multiplexing (OFDM) has proved to be a promising solution for many scenarios in UWA communication; on the contrary, it also amplifies the design challenges for implementing such schemes to acquire the required bandwidth efficiency. The goal of this study is to provide a comprehensive survey of the latest researches in the field of UWA MIMO-OFDM communication. The previous works are summarized, reviewed and compared according to their years of publication while problems faced by UWA MIMO-OFDM communication are highlighted. The articles are classified according to the focused techniques like channel estimation, equalization, coding and detection. Furthermore the works are compared based on the complexity and performance of the algorithms while some future research issues are identified.

      PubDate: 2017-03-04T06:07:03Z
      DOI: 10.1016/j.phycom.2017.02.007
  • Traffic-aware green cognitive radio
    • Authors: Washim Uddin Mondal; Sudipta Biswas; Goutam Das; Priyadip Ray
      Abstract: Publication date: Available online 27 January 2017
      Source:Physical Communication
      Author(s): Washim Uddin Mondal, Sudipta Biswas, Goutam Das, Priyadip Ray
      Cognitive Radio Network (CRN) has emerged as an effective solution to the spectrum under-utilization problem, by providing secondary users (SUs) an opportunistic access to the unoccupied frequency bands of primary users (PUs). Most of the current research on CRN are based on the assumption that the SU always has a large amount of data to transmit. This leads to the objective of SU throughput maximization with a constraint on the allowable interference to the PU. However, in many of the practical scenarios, the data arrival process of the SU closely follows an ON–OFF traffic model, and thus the usual throughput optimization framework may no longer be suitable. In this paper, we propose an intelligent data scheduling strategy which minimizes the average transmission power of the SU while maintaining the transmission delay to be sufficiently small. The data scheduling problem has been formulated as a finite horizon Markov Decision Process (MDP) with an appropriate cost function. Dynamic programming approach has been adopted to arrive at an optimal solution. Our findings show that the average transmitted power for our proposed approach can be as small as 36.5% of the power required for usual throughput maximization technique with insignificant increase in average delay.

      PubDate: 2017-01-28T19:33:32Z
      DOI: 10.1016/j.phycom.2017.01.002
  • Multiuser detection for the uplink of clustered 5G systems with universal
           frequency reuse
    • Authors: F. Casal Ribeiro; R. Dinis; F. Cercas; A. Silva
      Abstract: Publication date: Available online 24 January 2017
      Source:Physical Communication
      Author(s): F. Casal Ribeiro, R. Dinis, F. Cercas, A. Silva
      With 5G (Fifth generation) cellular communications, systems have to be able to cope with a massive increase of mobile devices and services and simultaneously improve the system’s spectral efficiency, as well as dealing with high interference levels. Base Station (BS) cooperation architectures jointly with block transmission techniques, such as OFDM (Orthogonal Frequency Division Multiplexing) for the downlink and SC-FDE (Single-Carrier with Frequency-Domain Equalization) for the uplink, are proven to be suitable for broadband wireless transmission systems. In BS cooperation systems MTs (Mobile Terminals) in adjacent cells share the same physical channel allowing the reducing of the frequency reuse and improving the spectral efficiency of cellular systems. In this paper we present a set of multiuser detection techniques for the uplink transmission in clustered architectures based on the C-RAN (Centralized-Radio Access Network) concept. We consider BS cooperation systems employing a universal frequency reuse approach. Our performance results demonstrate that by employing clustered techniques for the detection procedure it is possible to reduce substantially the signal processing complexity and the side information that must be transmitted by the backhaul structure.

      PubDate: 2017-01-28T19:33:32Z
      DOI: 10.1016/j.phycom.2017.01.006
  • Power control based on the Stackelberg game in two-tier femtocell networks
    • Authors: Zhixin Liu; Shiyi Li; Lili Hao; Hongjiu Yang; Xinping Guan; Xinbin Li
      Abstract: Publication date: Available online 21 January 2017
      Source:Physical Communication
      Author(s): Zhixin Liu, Shiyi Li, Lili Hao, Hongjiu Yang, Xinping Guan, Xinbin Li
      In this paper, the resource allocation strategy is investigated for a spectrum sharing two-tier femtocell networks, in which a central macrocell is underlaid with distributed femtocells. The spectral radius is introduced to address the conditions that any feasible set of users’ signal-to-interference-plus-noise ratio requirements should satisfy in femtocell networks. To develop power allocation scheme with the derived conditions, a Stackelberg game is formulated, which aims at the utility maximization both of the macrocell user and femtocell users. The distributed power control algorithm is given to reduce the cross-tier interference between the macrocell and femtocell with same channel. At last, admission control algorithm is proposed, aiming to exploit the network resource effectively. Numerical results show that the proposed resource allocation schemes are effective in reducing power consumption and more suitable in the densely deployed scenario of the femtocell networks. Meanwhile, it also presents that the distributed power allocation scheme combined with admission control can protect the performance of all active femtocell users in a robust manner.

      PubDate: 2017-01-22T16:39:22Z
      DOI: 10.1016/j.phycom.2017.01.005
  • Computation of information rates by means of discrete states density
    • Authors: L. Reggiani; L. Dossi
      Abstract: Publication date: Available online 20 January 2017
      Source:Physical Communication
      Author(s): L. Reggiani, L. Dossi
      Starting from the existing works on the computation of information rates of channels with memory, we present a modification of these methods that can be used for continuous-state space models. The principle used for developing this alternative method is based on the partitioning of the continuous-state space into sub-sets, each one representing a state of a trellis, and the association between the states and the probability density functions built and updated on such sub-sets. The paper discusses the cases in which the method provides a computational advantage and it presents numerical results regarding the relevant example of the Wiener phase noise model.

      PubDate: 2017-01-22T16:39:22Z
      DOI: 10.1016/j.phycom.2017.01.004
  • Multi-channel sensing and resource allocation in energy constrained
           cognitive radio networks
    • Authors: Kedar Kulkarni; Adrish Banerjee
      Abstract: Publication date: Available online 20 January 2017
      Source:Physical Communication
      Author(s): Kedar Kulkarni, Adrish Banerjee
      We consider a cognitive radio network in a multi-channel licensed environment. Secondary user transmits in a channel if the channel is sensed to be vacant. This results in a tradeoff between sensing time and transmission time. When secondary users are energy constrained, energy available for transmission is less if more energy is used in sensing. This gives rise to an energy tradeoff. For multiple primary channels, secondary users must decide appropriate sensing time and transmission power in each channel to maximize average aggregate-bit throughput in each frame duration while ensuring quality-of-service of primary users. Considering time and energy as limited resources, we formulate this problem as a resource allocation problem. Initially a single secondary user scenario is considered and solution is obtained using decomposition and alternating optimization techniques. Later we extend the analysis for the case of multiple secondary users. Simulation results are presented to study effect of channel occupancy, fading and energy availability on performance of proposed method.

      PubDate: 2017-01-22T16:39:22Z
      DOI: 10.1016/j.phycom.2017.01.003
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