Haibo Wang

Beijing Jiaotong University, Peping, Beijing, China

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Publications (27)15.29 Total impact

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    ABSTRACT: Device-to-device (D2D) communication underlaying cellular networks is an effective way to improve spectral efficiency and alleviate the traffic load of base stations, therefore it is considered as one of the key technologies in the fifth generation mobile communications, also referred to as IMT-2020. However, it also introduces interference between D2D terminals and cellular users. In this work, we adopt both exclusion regions (ERs) and open-loop fraction power control (OFPC) to mitigate the D2D-to-Cellular interference in a multicell uplink spectrum-sharing scenario. We derive the closed-form expressions of outage probability (OP) and area spectral efficiency (ASE) using stochastic geometry, and reveal the impact of the D2D user equipment (DUE) density versus cellular user equipment (CUE) density (in other words, how many DUEs can reuse the resource of a CUE per cell), D2D communication distance, different ER sizes, and of the compensation factor in OFPC. Numerical results show that adopting ERs could both decrease the OP of cellular users and increase the network ASE, and a proper ER radius can be selected by network operators according to their target OP, D2D users' density, and the communication distance of D2D users. Copyright © 2014 John Wiley & Sons, Ltd.
    07/2014; 26(1). DOI:10.1002/ett.2854
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    ABSTRACT: It is well-established that Device-to-Device (D2D) communication is a promising technology to improve spectral efficiency and reduce system power consumption simultaneously. In this paper, we build a tractable model for Device-to-Device communication underlaying multi-cell cellular networks to evaluate the coverage probability and area spectral efficiency by utilizing stochastic geometry. To mitigate the interference in this hybrid system, we adopt Exclusion Regions (ERs) around base stations to limit the locations of cellular users and active D2D users. Numerical results demonstrate that ERs could significantly improve the coverage probability and the system area spectral efficiency. Our results also show that the coverage probability target can still be achieved for the maximum allowed D2D communication distance or the maximum D2D pairs density by adjusting the ER radius.
    2014 ICC - 2014 IEEE International Conference on Communication Workshop (ICC); 06/2014
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    ABSTRACT: The performance of high-speed railway wireless communication systems is studied in the presence of co-channel interference and imperfect channel estimation in the uplink. The authors derive exact closed-form expressions for the outage probability and investigate the impact of fading severity. New explicit expressions are derived for both the level crossing rate and average outage duration for illustrating the impact of mobile speed and channel estimation errors on the achievable system performance. Our results are generalised and hence they subsume a range of previously reported results.
    IET Communications 05/2014; 8(7):1151-1157. DOI:10.1049/iet-com.2013.0674 · 0.74 Impact Factor
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    ABSTRACT: The effective throughput of multiple-input–single-output (MISO) systems communicating over both independent and identically distributed (i.i.d.) and independent and nonidentically distributed (i.n.i.d.) $kappa$– $mu$ fading channels is investigated under delay constraints. New analytical expressions are derived for the exact effective throughput of both channels. Moreover, we present tractable closed-form effective throughput expressions in the asymptotically high- and low-signal-to-noise-ratio (SNR) regimes for i.i.d. $kappa$– $mu$ fading channels. These results enable us to investigate the impact of system parameters on the effective throughput of MISO $kappa$ –$mu$ fading channels. We demonstrate that as the affordable delay tends to infinity, the effective throughput is increased to the classic ergodic capacity. By contrast, the effective throughput of delay-constrained near-real-time systems fails to approach the ergodic capacity.
    IEEE Transactions on Vehicular Technology 02/2014; 63(2):943-947. DOI:10.1109/TVT.2013.2277992 · 2.64 Impact Factor
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    ABSTRACT: In this paper, we analytically investigate Gallager's exponent for space-time block codes over multiple-input multiple-output block-fading channels with Gaussian input distribution. As a suitable metric of the fundamental tradeoff between communication reliability and information rate, Gallager's exponent can be used to determine the required codeword length to achieve a prescribed error probability at a given rate below the channel capacity. We assume that the receiver has full channel state information (CSI), while the transmitter has no CSI and performs equal power allocation across all transmit antennas. In the following, novel exact expressions for Gallager's exponent are derived for two well-known channel fading models, namely η-μ and κ-μ fading models. More importantly, the implications of fading parameters and channel coherence time on Gallager's exponent are investigated. In addition, we present new expressions for the Shannon capacity, cutoff rate and expurgated exponent for the above mentioned fading models, while in the high signal-to-noise ratio regime, simplified closed-form expressions are also derived. Finally, we highlight the fact that the presented analysis encompasses all previously known results on Nakagami-m, Rician, Rayleigh and Hoyt fading channels, as special cases.
    IEEE Transactions on Communications 03/2013; 61(3):1028-1039. DOI:10.1109/TCOMM.2012.120512.120327 · 1.98 Impact Factor
  • Haibo Wang, Kaixu Xia, Xiaoli Chu
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    ABSTRACT: We investigate the resource-sharing problem of Device-to-Device (D2D) communications underlaying the cellular network. The performance of D2D communications sharing the uplink channel of a cellular system is analyzed by first considering a single cell scenario for analytical tractability. Then we propose a position-based resource-sharing scheme for D2D communications underlying cellular system, and extend the performance analysis to multiple cells with Fractional Frequency Reuse (FFR). Numerical results reveal that the position-based scheme in conjunction with FFR provides a significant performance improvement.
    Communications in China (ICCC), 2013 IEEE/CIC International Conference on; 01/2013
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    ABSTRACT: In this paper, we analytically investigate the achievable rate of multiple-input single-output (MISO) channels in the presence of delay constraints. In particular, we focus on the so-called effective rate which was recently established as a suitable metric for assessing the impact of delay constraints on the overall performance of communication systems. Yet, most prior relevant works have considered only the typical cases of Rayleigh, Rician and Nakagami-m fading which allow for tractable manipulations. In this paper, we relax this assumption by considering MISO systems over η-μ fading channels. The η-μ distribution has been shown to provide very good fit to experimental data in various propagation environments. New, analytical expressions for the exact effective rate are derived. Moreover, we consider the asymptotically high and low signal-to-noise (SNR) regimes, for which tractable, closed-form effective rate expressions are presented. These results enable us to explicitly investigate the impact of system parameters on the effective rate of MISO η-μ fading channels.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
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    ABSTRACT: In this letter, we maximize the multicast capacity of a cellular system with dedicated decode-and-forward (DF) relays, by jointly optimizing transmission data rates of the base station (BS) and the relays subject to an average outage constraint in Rayleigh fading channels. The optimal transmission rates of the BS and relays and the optimal relay locations are obtained based on an outage probability analysis for the relay-assisted multicast. Numerical results show that relay-aided multicast significantly outperforms direct multicast, and the best transmission strategy is for the BS and dedicated relays to transmit at the same rate.
    IEEE Communications Letters 10/2012; 16(10):1592-1595. DOI:10.1109/LCOMM.2012.090312.120782 · 1.46 Impact Factor
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    ABSTRACT: In this paper, we analyze and evaluate the performance of digital communication systems that operate over a composite fading channel following the eta-mu/gamma distribution. More specifically, new analytical expressions for the channel capacity under different transmission schemes are derived in the form of infinite series. For the special case of integer mu values, simplified closed-form expressions are also obtained. Moreover, we deduce exact tractable formulas for the average bit error rate (BER) of various modulation schemes. In the high-power regime, simplified capacity and BER expressions are provided, revealing the implications of the model parameters on system performance. The relationship of the presented results with previously reported results on generalized-K and K fading channels is also established. We note that the theoretical results presented herein are given in analytical form, which can efficiently be evaluated.
    IEEE Transactions on Vehicular Technology 09/2012; 61(7):3114-3124. DOI:10.1109/TVT.2012.2199344 · 2.64 Impact Factor
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    ABSTRACT: This paper deals with channel estimation in time-varying channels for orthogonal frequency division multiplexing (OFDM) uplink transmission. By modeling the uplink channel properly, the time-varying channel response can be determined by estimating the channel parameters. These unknown channel parameters are coupled with each other due to multipath propagation. By exploiting the orthogonality of the training symbol, the channel parameters can be easily separated. Therefore, we can estimate the unknown channel parameters path by path, instead of complex joint estimation. This leads to great reduction of computational complexity. Moreover, an order-recursive algorithm is proposed, which can approximate the nonlinear nature of Doppler shifts with any-order Taylor expansion rather than only the second-order one in the literature. The proposed algorithm can outperform the existing algorithms due to the employment of higher order Taylor expansion. Theoretical analysis and simulations are also given, demonstrating the efficiency of the proposed algorithm.
    IEEE Transactions on Vehicular Technology 05/2012; 61(4):1709-1718. DOI:10.1109/TVT.2012.2187939 · 2.64 Impact Factor
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    ABSTRACT: In co-channel deployments of macro and femto cells, the much higher transmit power of a macrocell base station (MBS) than that of a femtocell access point (FAP) may create a femtocell exclusion region (FER) around an MBS, where reliable femto downlink (DL) services cannot be guaranteed. In this paper, we analyze the DL outage probability (OP) of orthogonal frequency division multiple access (OFDMA) based femtocells in terms of their locations with respect to nearby 3-sector MBSs, and derive the expression of FER radius as a function of the azimuth angle relative to the MBS, which can be directly used to divide the macrocell coverage area into inner and outer regions for hybrid frequency assignments. Simulation results show that the obtained closed-form expressions can be used to accurately predict the location-dependent femto DL OP and the non-circular FER in hierarchical 3-sector macrocells. Our results also show that the FER shrinks at edges between macro sectors, giving more space for co-channel deployment of femtocells to improve spatial reuse.
    Communications in China (ICCC), 2012 1st IEEE International Conference on; 01/2012
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    ABSTRACT: In this paper, an order recursive method is proposed to solve the joint estimation of channel impulse response (CIR) and carrier frequency offset (CFO) for orthogonal frequency-division multiplexing (OFDM) transmission. As long as one can obtain the solution for $Q$th-order Taylor expansion, the solution for $(Q + 1)$th order can also be obtained via a simple recursive relation. The proposed recursive algorithm actually provides a method to handle any $Q$th-order Taylor expansion, instead of just the second order adopted in the technical literature. Significant improvement can be observed by adopting higher order approximation. Analytical mean-square-error (MSE) performance results are given, demonstrating the efficiency of the proposed algorithm.
    IEEE Transactions on Vehicular Technology 11/2011; 60(9):4645-4650. DOI:10.1109/TVT.2011.2173362 · 2.64 Impact Factor
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    Xiaoli Chu, J.Y. Wu, Haibo Wang
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    ABSTRACT: Femtocells have been considered by the wireless industry as a promising solution not only to improve indoor coverage, but also to unload traffic from already overburdened macrocells. In spite of potentially excessive interference caused by densely deployed femtocells, macrocells may have to share the same spectrum with femtocells, due to spectrum availability and network infrastructure considerations. In this paper, we derive closed-form expressions for downlink outage probabilities (OP) of collocated spectrum-sharing macrocell and femtocells, based on the stochastic geometry theory. Orthogonal frequency division multiple access (OFDMA) is considered in the downlink of both macro- and femto-cells. Simulation results show that the derived OP expressions are able to predict OP performance of collocated spectrum-sharing macro- and femto-cells, and provide insights on the effects of different system and channel parameters on co-channel femtocell deployments.
    Communications (ICC), 2011 IEEE International Conference on; 07/2011
  • Haibo Wang, H.-P. Schwefel
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    ABSTRACT: In this paper, we present two novel ARQ schemes for mobile multicast, which utilize packet-combining to reduce the number of retransmissions. The spectral efficiency of these multicast ARQ schemes are optimized jointly with adaptive modulation and coding (AMC) under specific QoS constraints, and numerical results show that significantly gains can be achieved comparing to schemes without packet-combining. Delay analysis has also been fulfilled for adopting the proposed sub-optimal scheme in practical systems.
    Communications and Mobile Computing (CMC), 2011 Third International Conference on; 05/2011
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    ABSTRACT: Due to considerations of spectrum availability and network infrastructure, existing macrocell networks may have to share the spectrum with overlaid femtocells. In spectrum-sharing macro and femto networks, different transmit powers used by macro base stations (MBS) and femto access points, together with potentially densely deployed femtocells, may create dead spots where reliable coverage cannot be guaranteed to either macro or femto users. In this paper, we devise a decentralized strategy to regulate femtocell management of transmit power and usage of radio resources depending on its distance from the closest MBS. Simulation results for the orthogonal frequency division multiple access (OFDMA) downlink (DL) of spectrum-sharing macro and femto networks show that the proposed decentralized femtocell regulating strategy is able to guarantee reliable DL coverage over targeted macro and femto service areas while providing superior spatial spectrum reuse, for even a large number of spectrum sharing femtocells deployed per cell site.
    Proceedings of the 74th IEEE Vehicular Technology Conference, VTC Fall 2011, 5-8 September 2011, San Francisco, CA, USA; 01/2011
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    ABSTRACT: In mobile multicast transmissions, the receiver with the worst instantaneous channel condition limits the transmission data rate under the desired Quality-of-Service (QoS) constraints. If Automatic Repeat reQuest (ARQ) schemes are applied, the selection of Adaptive Modulation and Coding (AMC) mode will not necessarily be limited by the worst channel anymore, and improved spectral efficiency may be obtained in the efficiency-reliability tradeoff. In this paper, we first propose a Network-Coding-based ARQ (NC-ARQ) scheme in its optimal form and suboptimal form (denoted as Opt-ARQ and SubOpt-ARQ, resp.) to solve the scalability problem of applying ARQ in multicast. Then we propose two joint NC-ARQ-AMC schemes, namely, the Average PERbased AMC (AvgPER-AMC) with Opt-ARQ and AvgPER-AMC with SubOpt-ARQ in a cross-layer design framework to maximize the average spectral efficiency per receiver under specific QoS constraints. The performance is analyzed under Rayleigh fading channels for different group sizes, and numerical results show that significant gains in spectral efficiency can be achieved with the proposed joint NC-ARQ-AMC schemes compared with the existing multicast ARQ and/or AMC schemes.
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    ABSTRACT: Cooperative spectrum sensing scheme for Digital Multimedia Broadcasting-Terrestrial (DMB-T) system in China is investigated in this paper. There are three frame header modes defined in DMB-T Standard. For frame header mode 2, the only PN sequence is utilized to perform waveform-based spectrum sensing, and an improved synchronization algorithm is proposed. For frame header mode 1 and 3, extended pseudonoise (PN) sequences are proposed to be the local correlation sequences to perform waveform-based spectrum sensing. The performance of the proposed schemes is analyzed theoretically. Moreover, the performance of cooperative spectrum sensing schemes over the Rayleigh fading reporting channel is studied. When the probability of false alarm is 0.01 and the number of signal frame used is 1, it is shown that the probabilities of missed detection of the proposed schemes are much lower than that of the present PN correlation (PNC) and cyclic extension correlation (CEC) schemes. And the performance of the cooperative spectrum sensing is limited by both local detectors and the probability of reporting error.
    Proceedings of the 71st IEEE Vehicular Technology Conference, VTC Spring 2010, 16-19 May 2010, Taipei, Taiwan; 01/2010
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    ABSTRACT: In this paper, we present an innovative ARQ approach for mobile multicast, which utilizes packet-combining to reduce the number of retransmissions. We adopt the proposed ARQ scheme jointly with adaptive modulation and coding (AMC) in a cross-layer design framework to improve the average spectral efficiency per receiver under specific QoS constraints. Expressions are derived for the proposed joint ARQ-AMC schemes, which are then compared with existing multicast schemes under Rayleigh fading channels for different Signal-to-Interference-and-Noise-Ratios.
    Proceedings of the 6th International Wireless Communications and Mobile Computing Conference, IWCMC 2010, Caen, France, June 28 - July 2, 2010; 01/2010
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    ABSTRACT: In mobile multicast transmissions, the receiver with the worst instantaneous channel condition limits the transmission data rate under the desired Quality-of-Service (QoS) constraints. If Automatic Repeat reQuest (ARQ) schemes are applied, the selection of Adaptive Modulation and Coding (AMC) mode will not necessarily be limited by the worst channel anymore, and improved spectral efficiency may be obtained in the efficiency-reliability tradeoff. In this paper, we first propose a Network-Coding-based ARQ (NC-ARQ) scheme in its optimal form and suboptimal form (denoted as Opt-ARQ and SubOpt-ARQ, resp.) to solve the scalability problem of applying ARQ in multicast. Then we propose two joint NC-ARQ-AMC schemes, namely, the Average PERbased AMC (AvgPER-AMC) with Opt-ARQ and AvgPER-AMC with SubOpt-ARQ in a cross-layer design framework to maximize the average spectral efficiency per receiver under specific QoS constraints. The performance is analyzed under Rayleigh fading channels for different group sizes, and numerical results show that significant gains in spectral efficiency can be achieved with the proposed joint NC-ARQ-AMC schemes compared with the existing multicast ARQ and/or AMC schemes.
    EURASIP Journal on Wireless Communications and Networking 01/2010; 2010:10. DOI:10.1155/2010/807691 · 0.54 Impact Factor
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    ABSTRACT: In this paper we have investigated the joint power and rate adaptation strategies for multicast services for downlink communication. We have proposed a theoretical framework to find out the achievable spectrum efficiency upper boundary of such a scenario and the corresponding optimal solution for power and rate adaptation. Sub-optimal adaptation schemes were also studied and detailed parameter analysis was fulfilled. Numerical results show that one of the suboptimal adaptation schemes with constant power can achieve nearly optimal performance with the simplest adaptation function and parameter selection. The optimal parameter settings were also derived from the numerical analysis.
    Sarnoff Symposium, 2008 IEEE; 05/2008