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Mécanismes de handover inter système 3G-WiMAX. Etude des performances comparées d'une approche basée sur IP et d'une approche utilisant des protocoles radio de niveau 2

Abstract : Abstract In future mobile networks, different radio access technologies, such as GSM, UMTS, WiMAX, WIFI, will coexist. In order to realize a seamless vertical handover (inter-RAT handover) between these technologies, a variety of interworking architectures and inter-RAT handover mobility managements have been proposed. To propose an efficient inter-RAT handover solution, we first analyze a typical Layer 3 Mobile IPv6 (MIPv6) solution- Fast MIPv6 (FMIPv6). The numerical analysis demonstrates its drawbacks of uncertain handover latency and possible packet losses, and reveals the requirements for a seamless inter-RAT handover. Then, based on an integrated coupling architecture, we propose a novel common interworking sublayer (IW sublayer) at Layer 2 on RNC (Radio Network Controller) and MS (Mobile Station) to provide a seamless inter-RAT handover between UMTS and WiMAX systems. This IW sublayer solution focuses on eliminating packet loss and reducing handover latency, which are common challenges for most inter-RAT handover scenarios. This IW sublayer solution is also applied to the tight coupling architecture. In addition, two kinds of TCP Proxy, which interacts with the IW sublayer, are also introduced on the RNC in the integrated coupling architecture to resolve two typical inter-RAT handover problems for TCP traffics: BDP mismatch and spurious RTO. Because it is needed to periodically feed back ZWA (Zero Window Advertisement) messages to TCP sender to freeze its retransmission timer and congestion window, the first kind of TCP Proxy is suitable for frequent handover scenarios. In the second kind of TCP Proxy, the ACK Delaying and the explicit window notification mechanisms make it suitable for occasional handover scenarios. Compared with other vertical handover solutions, the simulation results show that our second TCP Proxy scheme with cross-layer mechanism has the merits of keeping existing TCP protocol stacks unchanged. All the conventional inter-RAT handover solutions are realized at Layer 2 or above due to the impossibility of a common module at physical layer and the geographical distance of source and target systems. But for the future LTE and WiMAX systems in the integrated coupling architecture, this is not the case, because they have some common physical techniques such as MIMO and OFDM. Two common modules named precoder and combiner are proposed respectively on BSs (Base Stations) and on MS at physical layer to exploit the maximum diversity of two RATs and to realize soft inter-RAT handover. This soft inter-RAT handover physical scheme is totally new to the best of our knowledge.
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Submitted on : Tuesday, November 16, 2010 - 4:09:39 PM
Last modification on : Friday, July 31, 2020 - 10:44:05 AM
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  • HAL Id : pastel-00005775, version 1



Bin Liu. Mécanismes de handover inter système 3G-WiMAX. Etude des performances comparées d'une approche basée sur IP et d'une approche utilisant des protocoles radio de niveau 2. Informatique. Télécom ParisTech, 2009. Français. ⟨pastel-00005775⟩



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