Research On Key Technologies Of Hybrid Network Based On 3G LTE

By introducing the ad hoc mode into the mobile cellular system, hybrid network has many benefits. In addition to imply coverage improvement and flow-equilibrium in cellular network, another important benefit is to deploy Adhoc network to a WAN. So it represents the trend of the next generation wireless network, and is gathering more and more attention.In order to be outstanding in the area of wireless network technologies, many projects have been started to study the hybrid network. Supported by a project of the 863 Program—"research on ad hoc networks based on 3G technology" and a project of the NSFC—"Research on the future mobile communication system which supports ad hoc mode", this thesis bring forward a hybrid network in which Adhoc network works as a twig-net of cellular network based on 3G LTE IMS system. Some key technologies are analyzed in this thesis, such as network architecture, calling control mechanism, micro-mobility management and agent select mechanism. The primary contributions on technologies in hybrid network are as follows:Based on the access network architecture brought forward by 3GPP R7, the network architecture to extend the coverage of cellular network which is named CEHN is bought forward in this thesis. There are three type of users: P-A, P-3G and A-3G users. Communication modes in hybrid network are divided into three types. Besides the access network architecture, IMS architecture in hybrid network is also designed in this thesis. In this architecture, all types of users and communication modes are supported by a new home domain named Adhoc home domain. Function of each module in this domain is described. Identification mechanism and address mechanism are also designed in this thesis.Upon three types of communication modes, the hybrid mode is analyzed especially in the requirements to calling control mechanism. Based on the characteristic of A-3G users, a calling control mechanism is brought forward in this thesis, which is formed by the independent calling control mechanism and the agent calling control mechanism of A-3G users. Two register mechanisms are analyzed in this thesis: IMPI mechanism and IMPU mechanism. Based on these two mechanisms, two agent-register methods are analyzed contrastively. Considering the modification to protocols in existence and network safety, a method to identify A-3G users is brought forward and based on this method, independent calling mechanism and agent calling mechanism are designed in this thesis.Based on the mobility characteristics of all kinds of users, the micro-mobility management is defined in this thesis. A micro-mobility management policy named ABMMP is described in this thesis. ABMMP make a good use of functions of agent nodes. It can locate the users by forming a point-link among agents that selected by users. Performances and costs of ABMMP and classical policy are analyzed contrastively. Predominance of ABMMP and the threshold are deduced. According to this threshold a micro-mobility management policy is brought out by improve ABMMP. Reactive and proactive agent-get mechanisms are studied in this thesis. Based on proactive mechanism, an agent-get mechanism named VSBAGM is brought forward which is implied in a virtual network. This thesis proposes a model to analyze the agent-get problem, introduces an objective function named Agent-Got probability, and deduces the analytical expression of Agent-Got probability under one-hop condition for the first time. The simulation results indicate that the analysis expression can accurately describe agent-get problem in HWN. Simulation analyses of the effects of each parameter on the agent-got probability in the situation of single cellular are conducted based on VSBAGM. Two models are proposed in this thesis to analyse the performance to set fixed agent node on the board of a cell. The effects of fixed node num and their transmit power on the coverage extend are analysed by simulation.Finally, the conclusion is given in the last part of the thesis, which contains the shortcomings of the proposed mechanisms, the improvements needed, and the prospect for the future work.