The Research On Mobility Management Of IEEE 802.16j Standard

Wireless and broadband are the trend of the modern networks.WiMAX,together with WCDMA,cdma2000 and TD-SCDMA,belongs to the 3G standards.It has some revolutionary technical characteristics,such as disposed easily,with access layer technics and telecommunication services.WiMAX technology can solve the "last kilometre" problem effectively.And it has a great impact on the wireless broadband technology and brings new opportunities.WiMAX is a broadband wireless metropolitan area network based on IP services. It is based on the IEEE 802.16 series standards,which belongs to wireless networks. From the first release of 802.16 standard IEEE framed in Oct 2001 to IEEE 802.16d standard framed in Jun 2004,namely,IEEE 802.16-2004,are all designed as fixed wireless access technology.The IEEE 802.16e standard issued in the end of 2005 began to support terminal mobility.With the development of the demands and technics,some extense standards of 802.16 family are discussed and set,which includes the IEEE 802.16j standard.802.16j standard brings in Relay Station(RS) to the 802.16e standard, with the purpose of increasing capability and cover area of the system.Due to the Mobile Subscriber Stations(MSS),the mobility management of the IEEE 802.16e and IEEE 802.16j standard should be emphasized.So two functions are mainly defined,namely,sleep mode operation and handover procedure.The sleep mode operation can decrease the energy consuming and the usage of the air interface resources.Handover can support the continuity of services,when the Mobile Station (MS) moves from a Base Station(BS) to another BS or the link quality falls because of interference.The mobility management in the IEEE 802.16j standard is more complicated than the IEEE 802.16e standard because of RS.The existing mobility managements are passive mostly,which just following the track of subscriber and managing the link between MS and network.This can't meet the need of the quickly developing modern networks.First,the sleep mode operation and handover defined in IEEE 802.16j are introduced briefly in this thesis.Then the performance of the sleep mode operation is analysed.In order to achieve better performance,the modification based on RS sleep mode and handover are focused on.The initiative mobility management is carried out by forecasting the traffic of network and the MS movement.My work is descriped as follows:1.The system model base on the Power Saving Classes of typeⅠin IEEE 802.16j standard is built using statistics,considering both the pulink and downlink traffic.The simulation on the analytical results by MATLAB are given and the influence of parameters on average energy consumption and average frame delay is analyzed.2.The parameters of the sleep window have great impact on the effect of RS sleep mode.An improved algorithm that dynamically changing parameters based on traffic stream is proposed in the thesis.The simulation results indicate that average energy consumption and average frame delay of RS sleep mode are reduced.3.The IEEE 802.16e handover is introduced briefly.And then the IEEE 802.16j Mobile Station handover scenarios are analyzed.The Intra-RS handover,which is the especial handover scenario for Mobile Stations in IEEE 802.16j standard,is paid more attention to.The handover model is built by mathematic methord.4.RS brings about more complicated and frequent handover problems because of cell boundaries increase.According to the special scenario and the law of MS movement,the MS motion model-based handover algorithm is proposed.The simulation results indicate that the proposed algorithm reduces the occurrence of handover,increases the intra-RS handover ratio and reduce the handover delay and lost packet ratio.