基于灰色预测的链路即将中断触发算法

及时有效的链路即将中断(LGD)触发机制对网络切换的性能有重要的影响。首先引入IEEE 802.21介质独立切换(MIH)标准,利用MIH提供的信息服务估计出网络切换所需时间,然后提出了一种基于灰色预测的LGD触发机制,通过估计的切换时间建立灰色预测模型,预测出终端的接收信号强度,动态确定触发时刻。并且为了降低预测开销,提出了基于信号衰减检测的灰色预测建模方法。仿真结果表明,算法实现了LGD及时有效地触发,而且可以减少不必要的预测开销,避免了终端资源的浪费。     

A novel re-authentication scheme based on tickets in wireless local area networks

Fast re-authentication schemes during handover of a mobile station are essential to seamless services for real-time multimedia applications in wireless local area networks. Although much research has been done to reduce re-authentication latency, the schemes developed so far either suffer from heavy burden problems or degrade the security level. In this paper, a novel ticket-based approach is proposed for re-authentication during handover. The mobile station receives handover tickets from the authentication server as a proof of authorization, and it presents the corresponding ticket when associating with a new access point. Our scheme reduces re-authentication delay to the delay of 2-way handshake between a mobile station and an access point. Furthermore, this scheme imposes less burden over the entities compared with other proactive key pre-distribution schemes, while satisfying 802.11i security requirements.     

LTE—A系统中基于多目标的CoMP切换算法研究

协作多点传输（CoMP）作为LTE—A系统中的一项关键技术,能消除或降低相邻小区间干扰,提升边缘用户的传输性能。由于这一新技术的弓l入,传统切换算法已经不能适应CoMP技术的切换要求,由此根据CoMP中联合处理（JP）技术的特点提出了一种新的切换算法。首先分析CoMP技术的实现原理并阐述了切换的概念,然后对传统A3切换算法和新的切换算法进行了研究,最后对两种算法的性能进行了仿真。结果表明：与传统A3切换算法相比,新的切换算法能提高系统吞吐量和减少系统切换总次数。     

Design of a USIM and ECC based handover authentication scheme for 5G-WLAN heterogeneous networks

A variety of wireless communication technologies have been developed to provide services to a large number of users. The future integrated 5G-WLAN wireless networks will support seamless and secure roaming, and various types of real-time applications and services, which will be the trend of next-generation computing paradigm. In this paper, we discuss the privacy and security problems in 5G-WLAN heterogeneous networks and present a logical 5G-WLAN integrated architecture. We also propose a novel USIM and ECC based design of handover authentication for next-generation 5G-WLAN heterogeneous networks that can provide secure and seamless Internet connectivity. Our scheme has the features of strong security and better performance in terms of computation cost, energy cost, and storage cost as compared with the state-of-the-art schemes.     

基于语音质量eSRVCC切换研究及优化策略

LTE系统内切换/系统间切换多数基于信号覆盖,无法有效解决信号强度良好情况下由于干扰导致VOLTE语音质量差的问题,本次研究重点是基于语音质量的eSRVCC切换,能够有效解决密集城区高干扰、县城农村快衰场景下信号质量差的问题,提升VOLTE语音通话质量。     

Improving Slow-start based probing mechanisms for flow adaptation after handovers

In a heterogeneous mobile networking environment, when a mobile user needs to perform a handover and switch to a new network, besides all the mobility management procedures to keep its connections alive and divert its on-going flows to the new location, the transmission rate of these flows should also be correctly adapted to match the conditions of the new network. One of the common practices is to let the flows to go through a fresh new Slow-start (or its variants) phase to probe along the path between the new location of the mobile user and its correspondent for the appropriate rate. Unfortunately, in many situations packets from these flows will be leaked into the new path at the old rate already before the Slow-start probing is performed, which not only interferes with the probing process but also disturbs the new network and affects the cross traffic along the new path. In this paper we propose to introduce some intelligence into the network, more specifically onto the mobility agent, so that this packet leaking issue is well taken care of before and during the Slow-start probing. On the other hand, with the introduced intelligence the probing process can also be improved in the sense of promptness, speed and data throughput, and these improvements are clearly demonstrated by simulation results.     

谈电力变压器的局部放电交接性试验重要性

本文旨在探讨电力变压器的局部放电交接性试验重要性,从局部放电的危害、局部放电交接性试验的功效两个方面进行探讨分析.从目前笔者多年电力运维检修实践经验来看,研究成果已具备,但仍存在一定的问题.这项试验对于电力变压器的安全运行中各个环节来说,都具有关键性的作用,需要引起运维管理人员的重视.     

WCDMA和GSM共同组网互操作技术与策略研究

首先对WCDMA和GSM共同组网互操作技术,如网络驻留、语音业务切换、数据业务重选、并发业务切换、业务与负载控制等进行分析,然后给出具体的选择策略。     

隧道场景RFD切换研究

通过对RFD切换的详细研究分析,提出了改善隧道切换、减少掉话的RFD切换优化方案。     

Handover Ranging Power Adjustment Using Uplink Channel Information in IEEE 802.16e/m

This letter proposes a handover ranging power adjustment scheme to improve handover performance. Incorrect ranging power can degrade handover performance due to the increased handover latency; therefore, the proposed scheme exploits the uplink channel information to adjust the uplink handover ranging power. Simulation results demonstrate that the proposed scheme reduces call outage probability by 33% compared to that of the conventional scheme. It also improves the number of users who satisfy the system requirements for handover interruption time.