Study On Cognitive Pilot Channel In Heterogeneous Environment

In future, various radio access technologies will compose a global, distributed, and cooperative working system - heterogeneous wireless communication system. With the aim to satisfy various users according to their requirements, the system will provide better services with originality and diversity at acceptable cost by the means of cooperative working between different radio networks.The emerging of heterogeneous wireless communication system will have a profound influence on the existing architectures of networks and terminals, and accelerate the evolution of the working procedures in both sides.Cognitive pilot channel (CPC) is one of most important practical technologies in future heterogeneous networks. It's also the research focus of E2R and WWRF. CPC provides fundamental support to network sensing, network selecting, and dynamic software downloading in heterogeneous environment. Up to now, in project - E2R II, the standardization process of CPC has been going on, and I, together with my colleagues, have also made a great contribution to it under the circumstances that our achievements on CPC research are effectively protected by the patent and the law of intellectual property. The rest of the dissertation is organized as follows. Some basic definitions and conceptions related to CPC in convergence of heterogeneous networks are introduced in Chapter 2; In Chapter 3, Chapter 4 and Chapter 5, the content CPC carries, the network selection algorithms with CPC assistance, and the network architecture of CPC are described in details, respectively.The parameters of radio resource management and physical layer in TDMA and CDMA are analyzed in this work, which determine the data content that CPC needs to carry and the terminal needs to detect. In heterogeneous systems, terminals need to thoroughly evaluate the service parameters that the neighboring network can provide before the handover is carried on. Terminals can collect the parameters, such as, the occupied rate of the networks, the delay, the integrity of the data, the price, and et al. through CPC broadcasting. However, the transfer rate of the data in terminal side is bonded with the mode of the networks, the state of the networks, and the channels between terminals and base stations, which can't be implemented by CPC unicasting. Taking advantage of CPC, the terminals combine the massive information broadcasted by CPC from the network side with the practical information collected about neighborhood to estimate the surroundings more accurately, which save the time of handoff, and is essential for vertical handover.In this paper, the network selection algorithms are investigated in the heterogeneous environment. These algorithms mainly consist of three parts, the parameters concerned, the measurement of the parameters, and the weighting of corresponding parameters. Based on the Grey theory, CPC assisted autonomous network selection algorithm from the terminal side sets the threshold in consistent with the different features of QoS services, and improves the performance of the networks; meanwhile, based on existing AHP algorithm, we focus on some key factors (i.e. the nation, the operators, user's preference, service requirements and the terminal requirements), and consider them in general, which is scalable. Simulation results show that the more inputs of the network selection algorithm, the better the performance of the networks. CPC's influences on the implementation procedure and structure of both the terminals and the networks are also illustrated in this paper. It is in power on of the terminals, network selection, and software downloading that CPC, which carries considerable control information, is applied. With respect to the advantages and disadvantages of both out-band CPC and in-band CPC, as well as the requirements of different scenarios, the out-band and in-band combining CPC method is proposed. To meet the real-time requirements of software downloading and updating, three significant functions of neighboring list and its non-enantiomorphous attribute are dwelled on; investigating into the developing trend of terminals in heterogeneous systems, we define the architecture of the network and the functions of the entities; furthermore, the new notion of frequency set about out-band CPC is put forward, which is crucial for the global use of CPC.A summarization is made in the end of this dissertation in which the future direction of CPC study is pointed out.