Showing papers by "Ying Wang published in 2009"

Joint Linear Filter Design in Multi-User Non-Regenerative MIMO-Relay Systems

Abstract: This paper addresses the filter-design issues for multi-user non-regenerative MIMO-relay systems. Based on the perfect channel state information (CSI), optimal joint linear filter schemes at the base station and the relay are derived, aiming to minimize the mean squared error (MSE). We first propose the joint optimal filter scheme in the downlink scenario along with a more practical suboptimal scheme, and then a closed-form optimal solution in the uplink scenario is exploited. Numerical results show that the proposed joint schemes can reduce the bit error rate (BER) significantly, especially for the high SNR case.

Median Based Network Selection in Heterogeneous Wireless Networks

Abstract: In heterogeneous wireless networks, rank aggregation based on multiple decision factors[1] has recently been proposed as a useful approach for network selection. For each decision factor, a rank of the candidate networks is derived according to the value of this decision factor. Then these decision factor dependent ranks are aggregated into a single rank and the top one is considered as a favorite network. However in the realistic scenario, the measurement on decision factor is often inaccurate so that the candidate networks are possibly not ranked appropriately. As a result, if there only exists the slight differences between the decision factor values of several candidate networks, same rank is preferable to these networks. The set of networks is therefore separated into several groups and these groups are ranked accordingly. Moreover the networks tied in the same group have the same rank. In this paper, a new approach namely median based network selection method is therefore proposed to handle such partial tied rank aggregation problem.

Joint linear filter design in multi-user cooperative non-regenerative MIMO relay systems

Abstract: This paper addresses the filter design issues for multi-user cooperative non-regenerative MIMO relay systems in both downlink and uplink scenario. Based on the formulated signal model, the filter matrix optimization is first performed for direct path and relay path respectively, aiming to minimize the mean squared error (MSE). To be more specific, for the relay path, we derive the local optimal filter scheme at the base station and the relay station jointly in the downlink scenario along with a more practical suboptimal scheme, and then a closed-form joint local optimal solution in the uplink scenario is exploited. Furthermore, the optimal filter for the direct path is also presented by using the exiting results of conventional MIMO link. After that, several schemes are proposed for cooperative scenario to combine the signals from both paths. Numerical results show that the proposed schemes can reduce the bit error rate (BER) significantly.

On the Performance of Downlink Transmission for Distributed Antenna Systems with Multi-Antenna Arrays

Abstract: In distributed antenna systems (DAS), the scenario that each antenna port is a multi-antenna array with multi-user is far beyond thoroughly studied. In this paper, the performance of four extended methods for DAS downlink transmission are analyzed and compared in such a scenario, two of which are based on the block diagonalization (BD) algorithm, namely joint BD and intra BD method. The other two methods are joint time division multiplexing (TDM) method and central antenna system (CAS) method. Both theoretic analysis and insightful simulations are utilized to evaluate these four methods. Theoretic analysis shows that the intra BD method requires less channel state information at transmitter (CSIT) and has lower computational complexity and process latency. Simulation results show that the intra BD method suffers only a little performance loss compared with the joint BD method. Overall, the intra BD method is proved to be a best tradeoff which achieves high capacity with relatively low complexity when power constraints are considered.

Semi-Distributed Resource Allocation Based on Multihop Equilibrium for Cellular OFDM-Relay Networks

Abstract: A semi-distributed resource allocation scheme based on multihop equilibrium is proposed for OFDM-relay networks. This method aims to reduce the amount of feedback information from the relay nodes (RNs). Moreover, it utilizes radio resource by striking an efficient balance between the capacities of the BS-RN link and RN-MS link. Simulation results show that the proposed semi-distributed scheme achieves good performances in terms of throughputs and fraction of satisfied users.

A Rule-Based Method to Personalized Services over Digital Broadcast and Mobile Converged Networks

Abstract: The digital broadcast and mobile converged (DBMC) networks are now hot in research, but there is little research on personalized services over any kind of DBMC net- works. This paper proposes a rule-based method to personalized services over DBMC networks. With the proposed approach, terminal can collect personalized service information from the broadcasted electronic service guide(ESG) and recommend these personalized services to the users for providing them with well user experience. Index Terms—personalized services, DBMC, rule, ESG, filter file