Hanwen Luo

Shanghai Institute of Technology, Shanghai, Shanghai Shi, China

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Publications (86)21.34 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper studies the precoder design of a multi-relay multi-user bidirectional networks in which each relay is equipped with multiple antennas. We study the relay precoder design in the case of imperfect channel state information (CSI) and a norm-bounded error model is adopted. Then, we solve the power minimization problem under this scenario. Numerical results demonstrate that the proposed robust precoding algorithm outperforms the non-robust solution.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
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    ABSTRACT: In recent years, there is a significant trend for VANET to provide not only traditional services like warning information exchanging for road safety and car collision avoidance but also various multimedia applications such as mobile TV which may require broadband access to core network or Internet. On the other hand, service provision technologies with point-to-multipoint transmission mode which could better utilize the limited wireless resource have been well discussed and standardized, such as MBMS in 3GPP and BCMCS in 3GPP2. In this paper, we propose an effective solution aimed to enable multicast/broadcast service provision in integrated VANET-cellular heterogeneous wireless networks based on a two-phase cooperative transmission strategy. Through analysis and simulation, our proposal combines advantages of these two heterogeneous networks and the nature of multicast/broadcast technology.
    Wireless Communications & Signal Processing (WCSP), 2013 International Conference on; 01/2013
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    ABSTRACT: In this letter, we study relay-aided networks with presence of single eavesdropper. We provide joint beamforming design of the source and relay that can minimize the overall power consumption while satisfying our predefined quality-of-service (QoS) requirements. Additionally, we investigate the case that the channel between relay and eavesdropper suffers from channel uncertainty. Finally, simulation results are provided to verify the effectiveness of our algorithm.
    IEEE Communications Letters 01/2013; 17(8):1544-1547. · 1.16 Impact Factor
  • Yuyi Li, Kai Ying, Lei Huang, Hui Yu, Hanwen Luo
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    ABSTRACT: The heterogeneous multicast networks are the networks with several wireless technologies that provide multicast service. Due to the high data rate of the service, point-to-point (P2P) transmission mode, which is employed by unicast channels, is no longer the best mode because of its inefficiency in power consumption and spectrum utilization. Compared with P2P, point-to-multipoint (P2M) transmission mode is recognized as a more promising mode for multicast service. But since P2M mode is provided by mulitcast channels who have turn-on thresholds, the P2M link of a transmission point (TP) is not always available for User Equipments (UEs). To deal with the UEs' cell/transmission mode selection problem in heterogeneous multicast networks, this paper proposes a novel auction mechanism. In the auction process, TPs act as auctioneers who own channel resource and UEs act as bidders who wish to buy these channels for multicast service. Different from many auction based mechanism, we design two kinds of prices, one for unicast channels providing P2P links and the other for multicast channels providing P2M links. In auction, the equilibrium is defined as the state that no UE wishes to change it decision. Through simulation, we show that the auction process converges to a equilibrium state, and the mechanism achieves about 40%-50% power efficiency compared with that of random access.
    Wireless Communications and Networking Conference (WCNC), 2013 IEEE; 01/2013
  • Ming Ding, Meng Zhang, Hanwen Luo, Wen Chen
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    ABSTRACT: In this paper, we investigate the robust beamforming schemes for a multi-user multiple-input-single-output (MU-MISO) system with per-antenna power constraints and quantized channel direction information (CDI) feedback. Our design objective is to maximize the expectation of the weighted sum-rate performance by means of controlling the interference leakage and properly allocating the power among user equipments (UEs). First, we prove the optimality of the non-robust zero-forcing (ZF) beamforming scheme in the sense of generating the minimum amount of average inter-UE interference under quantized CDI. Then we derive closed-form expressions of the cumulative density function (CDF) of the interference leakage power for the non-robust ZF beamforming scheme, based on which we adjust the leakage thresholds and propose two robust beamforming schemes under per-antenna power constraints with an iterative process to update the per-UE power allocations using the geometric programming (GP). Simulation results show the superiority of the proposed robust beamforming schemes compared with the existing schemes in terms of the average weighted sum-rate performance.
    IEEE Transactions on Signal Processing 01/2013; 61(21):5181-5192. · 2.81 Impact Factor
  • Kai Ying, Hui Yu, Hanwen Luo
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    ABSTRACT: Mobile and wireless communication has been evolved from the basic model for providing point-to-point voice centric services into more complicated service provision technologies with point-to-multipoint transmission mode, such as MBMS in 3GPP and BCMCS in 3GPP2. However, the group member with the worst channel condition becomes the bottleneck since the base station or access point is supposed to take care of all the users in a multicast group whose members would like to receive a same service. On the other hand, delay is one of the most important QoS criteria along with throughput especially for realtime services such as mobile TV and IP conference. In this paper, we propose a framework for performance analysis of multicast service with delay constraints. Additionally, an admission control policy for real-time multicast scheduling is demonstrated.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
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    ABSTRACT: In this paper, we will consider a coordinated multipoint (CoMP) transmission system which accords with the current Long Term Evolution-Advanced (LTE-A) system and the 5th generation wireless system (5G). This paper will consider two different circumstances, one concerning the condition that transmitters knows exactly which user will be wiretapped; the other concerning the condition that transmitters have no knowledge about the wiretapped user's index. Accordingly, we provide the corresponding precoding strategies and simulation results to verify the effectiveness of our proposed algorithms.
    Communications (ICC), 2013 IEEE International Conference on; 01/2013
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    ABSTRACT: Wireless devices have experienced great development in the past decade. During this period, secrecy studies have drawn heated attention. Traditionally, there mainly exist two methods to optimize secrecy transmissions, precoding scheme and artificial-noise-aided scheme. In this paper, we propose a joint design of precoding and artificial noise in a relay-aided network with the channel state information (CSI) already known. Besides, based on wiretapping knowledge known or not, defined by whether we have known which user is wiretapped, we proposed two different schemes. Simulation results are given to verify the effectiveness of our proposed schemes.
    Communications in China (ICCC), 2013 IEEE/CIC International Conference on; 01/2013
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    ABSTRACT: This paper studies the precoder design of bidirectional networks in which each node is equipped with multiple antennas. In contrast to the conventional model of bidirectional relay networks, this paper considers a more general scenario, i.e., a multi-user multi-relay network. First, by assuming that perfect channel state information (CSI) is available, we investigate the precoding design for the relays and users to minimize the sum mean squared error (MSE) and the maximum of single user's MSE, respectively. Then, we consider a more practical scenario where CSI estimation error is taken into account. By means of alternating optimization approach, we decompose the main problem into several decoupled subproblems with tractable solutions. It is shown that, in both the perfect and imperfect CSI cases, the proposed precoding algorithms outperform the existing solutions in terms of MSE and bit-error-rate (BER) performance.
    IEEE Transactions on Vehicular Technology 01/2013; 62(7):3228-3244. · 2.06 Impact Factor
  • Kai Ying, Hui Yu, Hanwen Luo
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    ABSTRACT: Green communication receives a growing number of concerns due to the consideration for energy and environment issues. On the other hand, the evolution of mobile and wireless communication also results in heterogeneous Radio Access Technologies (RATs), such as Wi-Fi, UMTS, LTE, CDMA2000 and so on. As a result, energy saving by inter-RAT cooperation has raised significant discussions in both industrial and academical worlds. In this paper, we concentrate on inter-RAT energy saving for multicast services. Moreover, we use Integer Linear Programming to model the problem and propose a distributed algorithm which can efficiently save the energy consumption.
    IEEE Communications Letters 01/2013; 17(5):900-903. · 1.16 Impact Factor
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    ABSTRACT: D2D (Device-to-Device) communication underlaying cellular networks will become a significant technology in the future to decrease the load of base station (BS) and improve the overall spectral efficiency. However, mutual interference will be brought out when D2D communication reuses the resource of cellular communication. System performance may be degraded a lot when severe interference has not been controlled. In this paper, we propose an efficient interference coordination mechanism for D2D communication, which is based on resource allocation by reasonably selecting cellular resources and controlling transmit power for D2D communication links. The proposed mechanism can increase the number of reliable D2D communication links in system while prioritizing cellular uplink communication. Simulation results show the efficiency of our proposed scheme.
    Communications in China - Workshops (CIC/ICCC), 2013 IEEE/CIC International Conference on; 01/2013
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    ABSTRACT: This paper investigates the Resource allocation problem in OFDMA-based decode-and-forward cooperative communication systems. The objective is to maximize the sum throughput under the constraints of joint total transmission power and subchannels occupation, while maintaining the maximum fairness among multiple relay nodes. Since the optimal solution to this combinatorial problem is extremely computationally complex to obtain, we propose a low-complexity suboptimal algorithm that allocates subchannel and power separately. In the proposed algorithm, subchannel allocation over the relay nodes is first performed under the assumption of equal power distribution. Then, an optimal power allocation algorithm named multi-level water-filling is used to maximize the sum rate. The simulation results show that the performance of the proposed algorithm can approach asymptotically to that of the optimal algorithm while enhancing the fairness among all relay nodes and reducing computational complexity from exponential to linear with the number of subchannels. It is also shown that the proposed equal power distribution algorithm with subchannel permutation (SP) outperforms the one without SP. KeywordsCooperative communication–OFDMA–Resource allocation–Fairness
    Wireless Personal Communications 02/2012; 62(3):655-670. · 0.43 Impact Factor
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    ABSTRACT: In this paper, we propose a sequential and incremental precoder design for downlink joint transmission (JT) network multiple-input–multiple-output (MIMO) systems with imperfect backhaul links. The objective of our design is to minimize the maximum of the substream mean square errors, which dominates the average bit error rate (BER) performance of the system. In the proposed scheme, we first optimize the precoder at the serving base station (BS) and then sequentially optimize the precoders of nonserving BSs in the JT set according to the descending order of their probabilities of participating in the JT. The BS-wise sequential optimization process can improve system performance when some BSs have to temporarily quit the JT operations because of poor instant backhaul conditions. In addition, the precoder of an additional BS is derived in an incremental way, i.e., the sequentially optimized precoders of the previous BSs are fixed, and thus, the additional precoder plays an incremental part in multi-BS JT operations. An iterative algorithm is designed to jointly optimize the substream precoder and substream power allocation for each additional BS in the proposed sequential and incremental optimization scheme. Simulations show that, under the practical backhaul link conditions, our scheme significantly outperforms the autonomous global precoding scheme in terms of BER performance.
    IEEE Transactions on Vehicular Technology 01/2012; 61(6):2490-2503. · 2.06 Impact Factor
  • Ming Ding, Jun Zou, Zeng Yang, Hanwen Luo
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    ABSTRACT: In this letter, we propose an efficient relay antenna selection algorithm for the amplify and forward (AF) two-way multiple-input multiple-output (MIMO) relay systems with analogue network coding (ANC). The proposed algorithm greedily selects the additional receive-transmit antenna pair that provides the maximum sum-rate. An iterative computation method is also designed to evaluate the sum-rate efficiently.
    IEICE Transactions on Communications. 01/2012; E95.B(4):1459-1462.
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    ABSTRACT: Vehicular Ad hoc Networks(VANETs) enable plenty of important applications for vehicles, such as accident prevention and traffic jam avoidance. However, VANETs can hardly provide reliable connectivity between vehicles, which makes data dissemination of the aforementioned applications extremely difficult. Compared with VANETs, 3GPP cellular networks(e.g., LTE), offer much more reliable connectivity. Furthermore, cellular networks ensures timely dissemination in large scales due to the broadcast nature. In this paper, we deploy a cellular-VANET heterogenous network achitecture to realize efficient data dissemination. In the heterogenous networks, a part of vehicles are selected as mobile gateways to connect the two kind of networks. Later, we apply the coalition game theory to stimulate vehicles to join coalitions which can maximize the efficient data rate. The simulation results show that, by following the protocal, maximin overall effective data rate can be achieved.
    01/2012;
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    ABSTRACT: The conventional semi-orthogonal user pairing algorithm in uplink virtual MIMO systems can be used to improve the total system throughput but it usually fails to maintain good throughput performance for users experiencing relatively poor channel conditions. A novel user paring algorithm is presented in this paper to solve this fairness issue. Based on our analysis of the MMSE receiver, a new criterion called “inverse selection” is proposed for use in conjunction with the semi-orthogonal user selection. Simulation results show that the proposed algorithm can significantly improve the throughput of users with poor channel condition at only a small reduction of the overall throughput.
    IEICE Transactions on Communications. 01/2012; E95.B(7):2485-2488.
  • Ming Ding, Jun Zou, Zeng Yang, Hanwen Luo
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    ABSTRACT: In this letter, we propose an antenna selection single frequency network precoding (AS-SFNP) scheme for downlink cooperative multiple-input multiple-output (MIMO) systems, which efficiently improves system capacity with low feedback overhead and low complexity.
    IEICE Transactions. 01/2012; 95-B:655-658.
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    ABSTRACT: This paper investigates the problem of joint design of relay precoders and receivers based on the minimum mean-square-error (MMSE) criterion in multi-hop bi-directional multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay systems. In contrast to the conventional research on two-way relay systems, we combine a multi-hop relay system with a bi-directional relay system which further enhances the system performance. By decoupling the original highly non-convex problem into three sub-problems, we propose an iterative algorithm to alternatively optimize relay precoders and receivers. Numerical simulation results show that the proposed iterative algorithm outperforms other algorithms in terms of bit-error-rate (BER).
    Wireless Communications & Signal Processing (WCSP), 2012 International Conference on; 01/2012
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    ABSTRACT: In this letter, the limited feedback scheme in MIMO-Relay systems is considered. We propose a new strategy that optimizes the allocation of feedback bits between channel direction information (CDI) and phase information (PI) for multi-relay systems under the total number of feedback bits constraint. The proposed scheme eventually trades off some CDI bits for PI feedback to diminish the phase ambiguity. Simulation results show that compared to the conventional and the 1-bit PI feedback methods, the proposed scheme remarkably improves the system performance without increasing the feedback overhead.
    IEEE Communications Letters 02/2011; 15:181-183. · 1.16 Impact Factor
  • Kai Ying, Hui Yu, Xinbing Wang, Hanwen Luo
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    ABSTRACT: Mobile and wireless communication has been evolved from the basic model for providing point-to-point (PtP) voice centric services into more complicated service provision technologies with point-to- multipoint (PtM) transmission mode, such as MBMS in 3GPP and BCMCS in 3GPP2. On the other hand, the evolution of mobile and wireless communication has also resulted in a large number of wireless technologies such as UMTS cellular network, WiMAX and WLAN. As a result, issues related to multicast/broadcast service over heterogeneous networks will be more complex, interesting and valuable. In this paper, we propose a solution aimed to provide seamless and ubiquitous support for multicast/broadcast service on heterogeneous accesses. Additionally, a vertical handover policy named PtM First for multicast resource management in heterogeneous networks is demonstrated.
    Proceedings of the Global Communications Conference, GLOBECOM 2011, 5-9 December 2011, Houston, Texas, USA; 01/2011