| Popis: |
This research focuses on a heterogeneous wireless cellular network consisting of small cells within macro cells. The thesis aims to provide a development direction to utilize the network resources to the utmost extent. It is started with random non coordinated networks. The main limiting factor in a non-coordinated network is the interference. Then step by step, more advanced schemes are added to the network to reduce or eliminate the interference and improve network's performance. At first, full coordination is added to the network. It is shown that although such a coordination improves the system rate in some scenarios, it cannot fit to the dynamics of the traffic demand in a cellular network. Therefore, a more advanced scheme is introduced. In this scheme dynamic coverage control of BSs alongside large scale clusters direct idle network resources from sparse areas to the congestion areas. This method is especially beneficial when there are some distinct congestion zones in the network. This scheme can achieve several times higher capacity than the previous schemes. In addition, by introducing rank adaptation in the large scale clusters the system rate can be increased even more. Then gain in the system rate can be more than 100 percent depending on the scenario and environment. This huge gain is a motivation for further study on the aspects and issues of the practical implementation. The last part of the thesis discusses the required measurement and signaling scheme for the practical implementation based on the concept of C/U splitting and signaling schemes that are currently considered in 3GPP standardization. This can insure the feasibility of the scheme. |
