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Olga Bordunova 

Scientific adviser: Vladimir Bessarab 

Research and development of optimization methods in CDMA networks

In modern society wireless communication systems have led to changes that we could not foresee. At present, mobile communication is an integral part in human’s life.

Communication is developing rapidly, and it increase the amount and quality of services. We can realize the innovations in two ways: by creating new technical solutions and by optimizing existing networks.

Nowadays there are CDMA networks in Ukraine such as CDMA Ukraine, Intertelecom, Welcom-Telecom, PeopleNet and MTS, which provide Internet access in the standard CDMA, so it will be better to optimize networks, rather than engineer them[1] .

Is a serious technical problem to ensure the effective operation of the network, which serves a lot of users. It can happen the situation, when during the planning network we’ll get characteristics that are very differ from real parametrs, in this case the network will operate inefficiently. It’s the urgency problem to develop CDMA optimization methods to improve their functioning.

The purpose of master’s thesis is to research and develop the optimization methods in CDMA network. It’s necessary to ensure the integral radio coverage to provide qualitative connection.

It is necessary to solve several tasks to achieve this goal:

1. to research CDMA optimization methods of the radio coverage;

2. to identify the criterion on which we will be optimize network;

3. to develop the mathematical optimization radio coverage algorithm;

4. to simulate the system.

Object of research is a segment of the CDMA network and its coverage characteristics.

Research methods. We used the mathematical apparatus of the radio propagation theory.

Communication of work with scientific programs, plans, themes. Master's qualification thesis is executed during 2010-2011 agrees with a scientific direction of the department “Automation and Telecommunications” of Donetsk National Technical University.

Prospective scientific novelty of the received results. Novelty of master's thesis is to improve the efficiency of the existing CDMA network through the development of radio coverage optimization algorithm.

Topic: " Optimization methods in CDMA networks » is wide enough. It should be carry out in stages. In this paper we’ll carry out the radio coverage optimization in the network.

Optimization is a complex of measures to ensure the maximal efficiency of use the existing hardware and software to minimize the cost of design network. While we’re carrying out optimization we use the mathematical model, objective function and optimization algorithm.

When we design a network is an important stage to plan it, planning network can get us the coverage of researching territory. These results are used for preliminary evaluation of the service area. Package of measures for optimizing the network aims to achieve high quality of communication, the maximum bandwidth, increasing the service area.

Optimization in CDMA networks is more important than NMT, AMPS, GSM networks, because neighboring base stations (BS) in such networks operate on different frequencies and levels of intersystem interference in this case is much lower. If there is insufficient frequency resource the capacity increasing of the CDMA network is achieved by increasing the density of the base stations location that still more difficult problem of intersystem interference and increases the dependence of the target parameters achievement on the optimization process effectiveness of the current and surrounding base stations [4].

1) Parametric optimization. When we use this optimization we change radio settings to improve and bandwidth management BS network, and to improve the quality of communication. This optimization is connected and held together with structural and antenna optimization. This method includes the static and dynamic parametric optimization.

2) The antenna optimization. When we use this method we change, the tilt angles, azimuths, antenna structures, antenna types, shapes of antenna directivity diagram. Antenna optimization is applied when necessary reallocation of the service area, subscriber load, to improve quality of services, reducing intersystem interference and interference mitigation. It distinguishes between static and dynamic optimization of the antenna.

3) Structural optimization. This method includes: a synthesis of multi-sectoral hybrid structures transceivers and antenna systems, as well as the synthesis of repeater systems.

4) Individual optimization. This method aims the detecting and eliminating the causes of subscribers complaints.

Thus, at this moment I try to justify the necessity of radio coverage optimization in the CDMA networks. In this abstract I studied the dependence of covering radius and height of the antenna lift and angle of inclination. A model of the airwave propagation Okumura-Hata was examined. It can be drawn a conclusion that, using RPS-2 we can take more informed decisions when we optimize the network to improve the system efficiency.