VERTICAL HANDOFF ALGORITHM IN HETEROGENEOUS NETWORKS FOR REDUCING INTERFERENCE

A vertical handoff decision algorithm in heterogeneous networks composed of CDMA Cell Networks (CN) and Wireless Local Area Network (WLAN) is proposed to minimize the total inter- ference in CDMA. The scope of WLAN is determined by minimizing interference and each commu- nicating node shall handoff to WLAN as soon as it enters the scope. We first propose a model for heterogeneous networks, and based on it we obtain the close-form expression of interference. In order to minimize interference, we use simulation annealing method to get the WLAN radius, which is called basic algorithm. In order to reduce the interference further, we improve the basic and get the enhanced algorithm. Through numerical computing, we analyze the interference in condition of different call arrive rates, and results show that the enhanced can reduce interference more greatly than the basic.

CurveNet:Curvature-Based Multitask Learning Deep Networks for 3D Object Recognition

In computer vision fields,3D object recognition is one of the most important tasks for many real-world applications.Three-dimensional convolutional neural networks(CNNs)have demonstrated their advantages in 3D object recognition.In this paper,we propose to use the principal curvature directions of 3D objects(using a CAD model)to represent the geometric features as inputs for the 3D CNN.Our framework,namely CurveNet,learns perceptually relevant salient features and predicts object class labels.Curvature directions incorporate complex surface information of a 3D object,which helps our framework to produce more precise and discriminative features for object recognition.Multitask learning is inspired by sharing features between two related tasks,where we consider pose classification as an auxiliary task to enable our CurveNet to better generalize object label classification.Experimental results show that our proposed framework using curvature vectors performs better than voxels as an input for 3D object classification.We further improved the performance of CurveNet by combining two networks with both curvature direction and voxels of a 3D object as the inputs.A Cross-Stitch module was adopted to learn effective shared features across multiple representations.We evaluated our methods using three publicly available datasets and achieved competitive performance in the 3D object recognition task.

Adaptive vertical handoff algorithm in heterogeneous networks

The integration of cellular network （CN） and wireless local area network （WLAN） is the trend of the next generation mobile communication systems, and nodes will handoff between the two kinds of networks. The received signal strength （RSS） is the dominant factor considered when handoff occurs. In order to improve the handoff efficiency, this study proposes an adaptive decision algorithm for vertical handoff on the basis of fast Fourier transform （FFT）. The algorithm makes handoff decision after analyzing the signal strength fluctuation which is caused by slow fading through FFT. Simulations show that the algorithm reduces the number of handoff by 35%, shortens the areas influenced by slow fading, and enables the nodes to make full use of WLAN in communication compared with traditional algorithms.

Performance Analysis of Anti-Interference UWB-OFDM System

This paper examines the robustness of anti-interference Ultra-Wide-Band UWB-OFDM （AI-UWB） systems in presence of narrow-band interference. It analyzes the bit error rate performance of the systems in both the single-user and multi-user modes, and compares its robustness in different code matrixes. By encoding transmitted symbols and spreading their power over all sub-bands, AI-UWB systems can make full use of the frequency diversity across the sub-bands and have more robustness to the narrowband interference. Simulating results show that different codes have almost the same robustness to the narrowband interference. The encoding and spreading could suppress the narrowband interference effectively. Compared with the IS-UWB systems, our approach has more than 5 dB interference margin.

Analysis of the call blocking rate of two-hop-relay cellular system in the dead spots

In a traditional cellular system, the call requests initiated by mobile stations （MSs） must be carded through a base station （BS） via the cellular interface, but when MSs are located in the dead spots, their call requests will be blocked because the MSs cannot communicate with the BS. It is considered to relay these blocked calls requested using Ad-hoc network, which will improve the performance of the system as a whole. This article first introduces a novel architecture of the two-hop-relay cellular system in the dead spots, and then analyzes and compares the call blocking rate of the traditional cellular and the two-hop-relay cellular system respectively under three different conditions. The first and second conditions are the traditional cellular system without and with taking account of the effect of the dead spots. The third condition is the two-hop-relay cellular system with taking account of the effect of the dead spots. Numerical analytical result shows that the two-hop-relay cellular system can obtain lower call blocking rate than the traditional cellular system when considering the effect of dead spots. Consequently, this novel architecture can resolve the problem of coverage limitation of a traditional cellular system effectively.