Cell Planning For Heterogeneous Wireless Networks

The contradictions between ever-increasing wireless communication demands and scarce spectrum resources drive human to develop new technologies and spectrum reuse mode. Traditional wireless network is expanded by the way of "cell splitting", which offers a high spectrum reuse mode to gain larger capacity of the network. Though this technique allows a large quantity of users to access network, too many base sta-tions are built in a blind competitive and carelessly way, which imposes a large amount of cost to establish networks and huge amount of energy consumption. Among the pro-posals of next generation networks, heterogeneous networks, in behalf of LTE/LTE-A, is deemed as a promising solution, which could cover the traffic demand while in a cost-effective way. Heterogeneous wireless networks, by exploiting small cell, such as pico cell, femto cell, take the advantages of low-power, short distance to improve the quality of links, which can add much more capacity and lift the performance of sys-tem. Unfortunately, the flexible deployment of small cells causes the loss of similarity between cells, which projects a dilemma situation to operators in designing, deploying and maintaining networks for the lack of path loss prediction method except conducting repetitive road testing. Additionally, different cell size push the interference manage-ment out of control. And, more importantly, carelessly planning base station causes unbalanced traffic between base stations that degrades the performance of whole sys-tem and wastes scarce system resources. However, heterogeneous network planning is a different world from traditional way, in which an overall consideration to the deploy-ment of base station is urgent to be launched. In this thesis, We focus on cell planning for heterogeneous networks to address the problem mentioned above.The main contributions of this work are summarized as follows:1. Analyzed the necessity and challenges for heterogeneous network cell planning. Combining the traditional cell planning methods and features of heterogeneous network, we give an analysis of the factors that drive the wireless network for-ward from a cell planning perspective, and discuss the difference, necessity and challenges of cell planning for heterogeneous network in compromise with tra-ditional way.2. Proposed a new method to predict the path loss with limited road test data. In this work, we try to rebuilt the distribution of path loss from the limited road test data and seek a prediction model. Simulation and verification results show that the error is within 6dBm, which will be a good reference and guide for cell planning and designing.3. Proposed a cell planning method based on traffic balance and equal service area. Similar parameters and balanced traffic will boot the performance of system and mitigate interference. So we propose and formulate a traffic balanced with e-qual service area cell planning model. And developed its optimal solution by discretization and primal-dual techniques.In summary, we addressed the necessity and challenges of cell planning for het-erogeneous network, firstly. A path loss method based on the road test data is proposed. Finally, we formulated a traffic balanced with equal service area cell planning model, and develop its optimal solution. Those results throw some insights to cell planning for heterogeneous networks.