Design And Implementaion Of IEEE802.16e Network Entry Control Subsystem

One of the key tendencies for the current development of the wireless communication is that the broadband becomes wireless.As the stand of mobile broadband wireless metropolitan area network technology,IEEE 802.16e has achieved significant progress because of its advantages and has become one of the 3G standards.IEEE 802.16e standard is the most important one in the series of 802.16 standards,and it specifies the air interface technologies,including the medium access control layer(MAC) and the physical layer.Network entry control is the key part of IEEE 802.16e.In this thesis, according to IEEE 802.16e specification,the core subsystem of IEEE 802.16e MAC software system - network entry control subsystem is designed and implemented.In IEEE 802.16e,binary exponential backoff(BEB) algorithm is used to send ranging code during network entry procedure,in this thesis,our research focus on the random access merchanism of broadband wireless communication,and an improved algorithm is disscussed and the performance of the algorithm is evaluated by simulation.This thesis firstly introduces the research background,the current research and the organization of this thesis.Next,we introduce the IEEE 802.16 standard and the protocol statck,then emphatically analyze the network entry part of the protocol,then discuss the procedure of ranging and the channel descriptor upate in detail,and we design a IEEE 802.16e network entry subsystem of both Base Station and Mobile Station side.According to the design,the network entry subsystem's implementation under Linux 2.6 kernel space is discussed.At the end of this thesis,the random contention access algorithm of IEEE 802.16e is discussed,an improved algorithm which combines exponential increase exponential decrease(EIED) and binary negative-exponential backoff(BNEB) algorithm that is called EI_BNEB is analysed.An BEB+EI_BNEB algorithm that EI_BNEB and BEB algorithm are both applied to IEEE 802.16 system.The simulation result demonstrates that use the BEB+EI_BNEB algorithm,the system can achieve better performance of both average collision probability and average access delay.