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.     

被动微波/红外成像复合导引头交班性能的改进方法

通过对舰空导弹复合导引交班问题的研究,分析出交班过程中存在控制信号一致性和衔接性问题;经分析后,建立了复合导引头各子系统跟踪回路的数学模型且进行了简化,并构建出其制导控制系统的数学模型;以此制导控制系统数学模型为基础,进行了舰空导弹防御反舰导弹类目标时,典型情况下交班过程的仿真分析;结果表明:交班过程对弹道有一定扰动影响;针对此问题,以自适应交接律的思想为基础,交班时采用交班算子进行交班,或弹目距离较远且交班时采用追踪法为导引律;仿真结果表明:采用一次函数或正弦函数作为交班算子及远距离交班时,采用追踪法均可以降低交班对弹道的扰动程度,改善了交班性能.     

CDMA高铁覆盖规划优化浅析

随着铁路的大面积提速和城际高速铁路的快速建设,对现有移动通信网络的规划建设和建成后的网络优化提出了更高的要求。本文分别从多普勒效应、高速移动对切换带来的影响、专网覆盖及容量对高速铁路规划进行了分析探讨。     

SIP-based proactive and adaptive mobility management framework for heterogeneous networks

In this paper, we present and evaluate the performance of a mobility management system called the Proactive and Adaptive Handover (PAHO) system. PAHO is an application-level approach that uses SIP to manage client-initiated connection handoff across heterogeneous networks based on the IEEE 802.21 framework with designated user/configuration policy. Unlike conventional systems which make sub-optimal decision when managing connection handoff due to limited awareness of the relevant context for the application/service being delivered, PAHO defines proper interface to interact with the application as to determine when and to where the handoff and/or codec switching should take place in the event of network performance degradation. The results showed that using the PAHO approach on an audio/video conferencing session helps reducing the overall handover delay from 10.766 s (on non-PAHO system) down to at least 288 ms, and slowing down the degradation of MOS value throughout the entire experiment in the event of signal degradation as well as network congestion. It is also shown that load balancing among the access points (AP) could be achieved with an improved Information Server (IS).