Weihua Zhou

Non-orthogonal waveform transmission technique with convolutional multiplexing signalling

A non-orthogonal waveform transmission (NOWT) technique with convolutional multiplexing signalling (CMS) is introduced and analyzed, which can improve the data rate and spectrum efficiency of the wireless communication system. By narrowing the time interval of pulse shaping filter and overlapping parallel data branches together, the technique can obtain preferable gains compared with Nyquist signalling in the band-limited Gaussian channel, as well as frequency selective fading channel. The technique decreases Eb/N0 threshold distinctly compared with M-QAM technique, which can be used in the power efficient communications. Its proved that Nyquist signaling is not the optimal transmission criterion, and capacity of NOWT technique outperforms that of Nyquist system.

A Key Tree Merge Algorithm in Multi-privileged Groups

Many group key management schemes designed for hierarchical access control have been put forward recently. Some of these schemes use the integrated key graph to provide multiple levels of access control. However, most of these schemes focused on the efficiency of group key establishment and rekeying in centralized group key management schemes and didnt indicate how to generate the key graph. In this paper, we presented a Multiple Key tree Merge (MKM) algorithm to generate the optimal key graph and improve the group key establishment and rekeying efficiency of contributory group key agreement schemes. Efficiency evaluation indicates that an approximately 30% reduction in computation overhead is achieved compared with that of the MG scheme.

Performance analysis of A NOWT scheme for high spectral efficiency communications

Performance analysis of a bandlimited nonorthogonal waveform transmission (NOWT) scheme for high data rate wireless communications is presented. The technique is a potential alternative to classic orthogonal multiplexing techniques such as OFDM and QAM. It shows faster data transmission rate than Nyquist rate, and considerable performance gain compared with orthogonal techniques, as well as much lower peak to average power ratio (PAPR). The error probability in AWGN channel is derived, and the free squared Euclidean distance of NOWT signal is no more than the minimum squared distance of its modulation constellation. Analysis and numerical results demonstrate that the bandwidth efficiency and capacity of cod-ed/uncoded NOWT technique is higher than Nyquist signalling and orthogonal techniques.

Optimal DoF and Closed-Form IA Design for K-User MIMO-OFDM Systems

Combining multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) techniques, interference alignment (IA) enables concurrent transmission of multiple data streams with interference-free, and enormously enhances the system throughput. In this paper, we first explore the channel character of diagonal-block, to achieve the optimal DoF using IA in

Exploiting social relationship for secure routing in mobile social networks

K

Flexible multi-path routing for global optimization in software-defined datacenters

-user MIMO-OFDM systems. With finite frequency extensions, the total normalized degree of freedom (DoF) can be achieved by

Joint User Association and Resource Allocation for Interference Mitigation and Load Balancing in HCNs

frac{K}{2}

A non-orthogonal waveform superposition scheme for high efficient and reliable communications

. Furthermore, we provide the closed-form precoding and filtering matrices, without complex iteration. Simulation reveals the sum-rate performance we achieved is higher than that in previous works, and the complexity of closed-form solution is much lower than that of iterative algorithms.

Energy-efficient and mobility-aware dynamic Intercell Interference Coordination in Heterogeneous Networks

Mobile social networks (MSNs) are modern paradigms of delay tolerant networks, which exploit human mobility and consequent wireless contacts between mobile devices to share information in a peer-to-peer manner. Since routing in MSNs depends heavily on the cooperation among participating nodes, selfish or malicious behaviors of nodes impact strongly on the routing performance. In this paper, we introduce the social relationship evaluation method (SRM) for detecting the quality of human social relationship and propose the trustworthy behavior evaluation method (TBM) which exploits recommendations from close friends to detect nodes selfish or malicious behaviors. Based on SRM, we define the community of each node as the set of nodes having close social relationships with this node either directly or indirectly, and define the local community centrality to identify influential nodes for message forwarding in the community. Then, we propose SSRS, a novel social-based secure routing strategy, which exploits social relationships to enhance routing security and performance. Simulations have been conducted on the real world data set and results demonstrate that SSRS achieves better performances than the existing algorithms.

A multi-criteria handover algorithm for UE energy efficiency and cell load balance in dense HetNets

Existing traffic engineering strategies can achieve locally optimized network capability by uniformly leading flows to candidate paths. From a global network view, software defined network (SDN) allows a central controller to steer traffic effectively, and to improve network performance significantly, both for backbone and data center networks (DCNs). However, rational using of limited or expensive resources is very important in SDN, e.g., ternary content addressable memory (TCAM). In this paper, we focus on satisfying global network objectives such as delay and packet loss, with a comprehensive consideration of other criteria (network throughput and forwarding table size). We present a flexible multi-path routing scheme and formulate this as a mixed integer linear programming. Its turned out by simulation results and analysis that the delay and packet loss performance using proposed global algorithm outperforms other existing algorithms.