Cross-Layer Design of the Inter-RAT Handover between UMTS and WiMAX

Bin Liu,Philippe Martins,Philippe Bertin

doi:10.1155/2010/763614

Bin Liu, Philippe Martins + Show 1 more

Open Access

https://doi.org/10.1155/2010/763614

Copy DOI

Abstract

In future mobile networks, different radio access technologies will have to coexist. IEEE 802.21 MIH (Media-Independent Handover) provides primitive mechanisms that ease the implementation of a seamless vertical handover (inter-RAT handover) between different radio access technologies. However, it does not specify any handover execution mechanism. The first objective of this paper is to propose a novel MIHF (Media-Independent Handover Function) variant, which is renamed interworking (IW) sublayer. IW sublayer provides a seamless inter-RAT handover procedure between UMTS and WiMAX systems. It relies on a new intersystem retransmission mechanism with cross-layer interaction ability providing lossless handover while keeping acceptable delays. The second objective of this paper is to design a new TCP snoop agent (TCP Snoop), which interacts with the IW layer in order to mitigate BDP (Bandwidth Delay Product) mismatch and to solve spurious RTO (Retransmission TimeOut) problems. The cross-layer effects on the handover performance are evaluated by simulations. Our results show that cross-layer interaction between IW layer and TCP Snoop smoothes the handover procedure for TCP traffics. Additionally, this novel inter-RAT cross-layer scheme has the merit of keeping existing TCP protocol stacks unchanged.

Highlights

The future fourth-generation (4G) systems will coexist with different radio access technologies, such as GSM/GPRS, UMTS, WiFi, and WiMAX
The FTP session starts at 0.4 sec, and the MS starts performing hard handover at about 4 sec after it enters into the coverage region of WiMAX or UMTS
This paper evaluates and highlights the cross-layer effects for the seamless inter-RAT handover between UMTS and WiMAX networks on the basis of the integrated and tight coupling architectures

Summary

Introduction

The future fourth-generation (4G) systems will coexist with different radio access technologies, such as GSM/GPRS, UMTS, WiFi, and WiMAX. Multimode or multi-RAT MS (Mobile Station) shall have the ability to seamlessly roam among these heterogeneous networks without disrupting ongoing sessions or connections. Intensive research efforts have been made to define efficient seamless mobility procedures, commonly referred to as vertical handover or inter-RAT (Radio Access Technologies) handover. Many proposals to solve the mobility management problems in heterogeneous wireless networks can be found in the literature. [1] defines the Mobile IPv6 within the network layer to provide transparent support for host mobility. It introduces movement detection, IP address configuration, and location update procedures. Many experiments and simulations have shown difficulties in efficiently maintaining sessions’ continuity during handover, due to long latency and high packet loss rate issues [2]

Objectives

Results

Conclusion