Vertical Handoff in Heterogeneous Network Using Relay Technology in Mobile WiMax (original) (raw)

Handoff for Wireless Networks with Mobile Relay Stations

Wireless Relay networks have become very important technologies in the future wireless systems. Current research works mostly focus on scenarios where relay stations are either stationary or mobile with uniform velocity. However, in many applications, relay stations are mobile with irregular patterns. In particular, when mobile relay stations (MRSs) are deployed to complement the cellular systems, many issues such as handoff should be carefully investigated. In this paper, we focus on the handoff problem and propose a new handoff decision algorithm based on the relative velocities of user equipment (UE) to the serving access point (AP) and the target AP. We have show that the proposed handoff algorithm can significantly improve the handoff successful rate when the mobile relay station changes its moving patterns.

HANDOVER TECHNIQUES FOR RELAY-ENHANCED MOBILE WIRELESS BROADBAND NETWORKS

ABSTRACT There has been increasing interest in multi-hop relaying concepts as a key technique for increasing throughput and extending coverage of the cellular networks. Due to the existence of a large number of cells in multi-hop relay networks, the coverage areas of the access cells overlap to some extent. Hence, handover is needed to allow full mobility of users among those access cells. This paper studies various handover techniques for Time Division Duplex (TDD)– Orthogonal Frequency Division Multiple Access (OFDMA)-based multi-hop relay networks at a vehicular mobile station (MS) speed. The evaluated performance metrics are the downlink carrier to interference and noise ratio (CINR), downlink spectral efficiency and the selection probability of the modulation and coding schemes (MCS). Simulation results show that Macro Diversity Handover (MDHO) outperforms Fast Base Station Switching (FBSS) and Hard Handover (HHO).

Analyzing the performance of WiMAX zone handover in the presence of relay node Qualnet6.1

IOSR Journal of Electronics and Communication Engineering, 2014

Handover (HO) mechanism in mobile Wimax is one of the critical operations. It takes place when a mobile station (MS) moves from a serving base station (SBS) to another base station (BS). However, the handover schemes are adopted in mobile Wimax and hard handover is defined as mandatory. Since the data transmission should pause during handover process, it causes delay in mobile communication. The handover delay makes service degradation in system performance when implemented in real-time application such as Voice over IP (VoIP) and Internet protocol Television (IPTV). This paper propose an improvement in handover scheme for mobile WiMAX. which addresses the heterogeneous network. We evaluated the performance metrics such as handover latency and data loss performance for different WiMAX cell handover. In addition, we as also modified our simulation model of Mobile service for the analyzing the performance of WiMAX zone handover in Qualnet

Handover in mobile wimax networks: The state of art and research issues

2010

Abstract The next-generation Wireless Metropolitan Area Networks, using the Worldwide Interoperability for Microwave Access (WiMAX) as the core technology based on the IEEE 802.16 family of standards, is evolving as a Fourth-Generation (4G) technology. With the recent introduction of mobility management frameworks in the IEEE 802.16 e standard, WiMAX is now in competition with the existing and forthcoming generations of wireless technologies for providing ubiquitous computing solutions.

On the design of fast handovers in mobile WiMAX networks

2013

This Thesis is an embodiment of some research work carried out towards achieving faster and more reliable handover techniques in a Mobile WiMAX (Worldwide Interoperability for Microwave Access) network. Handover, also called handoff, is the critical mechanism that allows an ongoing session in a cellular mobile network like WiMAX to be seamlessly maintained without any call drop as the Mobile Station (MS) moves out of the coverage area of one base station (BS) to that of another. Mobile WiMAX supports three different types of handover mechanisms, namely, the hard handover, the Fast Base Station Switching (FBSS) and the Micro-Diversity Handover (MDHO). Out of these, the hard handover is the default handover mechanism whereas the other two are the optional schemes. Also, FBSS and MDHO provide better performance in comparison to hard handover, when it comes to dealing with the high-speed multimedia applications. However, they require a complex architecture and are very expensive to impl...

A Mobility Improvement Handover Scheme for Mobile-WiMAX

International Journal of Computer Applications, 2010

This paper presents a mobility improvement handover algorithm with less scan time implementation for Mobile WiMAX. Mobile WiMAX is a wireless technology based on IEEE802.16e for broadband wireless access. Mobile WiMAX introduces the most significant new feature, mobility to support for handovers, which can be considered as a basic requirement for mobile communication system. The mandatory handoff method is Hard Handoff for Mobile WiMAX and other two optional soft handoff methods are Macro Diversity Handoff and Fast Base Station Switching Handoff method. Handover delay generates during data transmission but handover delay should be less than 50milli second for real time applications such as VoIP. The existing draft standard considers only the received signal strength (RSS) when deciding handover. The mobility improvement handover scheme that depends upon the velocity factor has been taken into consideration in this paper. The proposed scheme skips some unnecessary handover stages, reduces handover delay by adjusting the handover parameters viz. handover RSS trigger and threshold handover RSS trigger value to improve the velocity of the mobile station. The proposed scenario has been implemented using QualNet network simulator which has lead to less handover time.

Performance Evaluation of Handover Technique in Mobile WIMAX Networks

WIMAX is an emerging wireless technology which is used for creating multi-hop mesh networks offering variable and high data rates, QoS, seamless mobility within a network. Mobile WIMAX is the technology that achieves requirements of broadband wireless access over long distance. It has the ability to provide users with a high speed wireless connection. In mobile WIMAX, it is necessary to provide handoff in order to support effective services mobility and to guarantee continuous network connectivity. This paper is focused on the performance analysis of handoff technique to provide mobility to the WIMAX networks – based IEEE 802.11e along with enhanced QoS. Also, a performance evaluation of QoS classes (UGS, ertps, and rtps) is analyzed and investigated over voIP applications. We evaluate our designed scheme in OPNET Modeler simulator and its performance is verified. Simulation results show that the designed WIMAX module – based rtps scheduling service outperforms WIMAX module – based (ertps and UGS) services, also some parameters of WIMAX do not have any influence on handoff latency, while others have effect on handoff latency. The results also show that handoff times could vary for different speeds of the Mobile Station (MS).

Simulation and evaluation of WIMAX handover over homogeneous and heterogeneous networks

Different aspects of wireless networks are changing as a result of the continuous needs in terms of speed, data rates and quality of service. Such aspects are required to be adaptable within the same network or among networks of different technologies and service providers. Consequently, Worldwide Interoperability for Microwave Access (WiMAX) is one of the future generation networks (4G) that needs further study. However, a major consideration for WiMAX to achieve mobility is the handover mechanism that concerns with the mobile station movement within the range of network coverage from one base station to another similar homogeneous or different homogeneous network. In this paper, an intensive analysis to handover mechanism in WiMAX followed by comparisons to WiMAX performance with UMTS and WiFi networks is carried out. QualNet 4.5.1 simulator is used to simulate the comparison process homogeneously and heterogeneously. Performance metrics of Throughput, End-to-End (E-2-E) Delay and Jitter in the comparison during handover process in/between the wireless networks are used. The simulation results are evaluated to identify the performance of the handover process over WiMAX-WiMAX, WiMAX-UMTS and WiMAX-WiFi with respect to the selected metrics. The environment of Wi-MAX-WiMAX has shown substantial enhancement of the system Throughput, reduction of E-2-E Delay and Jitter.

Optimization of handover scanning procedure in WiMAX networks with relay stations

3rd International Symposium on Wireless Pervasive Computing, ISWPC 2008, Proceedings, 2008

This paper proposes an optimization of management messages and their exchange during a scanning procedure of mobile station's neighborhood in WiMAX based networks with relay stations. The scanning procedure allows a mobile station to obtain information about handover target access stations. In IEEE 802.16e standard, where the relay stations are not considered, the exchange of requested information for handover execution is done among base stations and backbone network. When taking into account the relay stations, a new wireless interface among the base stations and relay stations emerged. Thus, a new communication scheme over the radio interface has to be proposed and optimized in order to reduce the management information overhead and to maximize the user data throughput.