Construction of the CDMA segment of a telephone system of the general using for territories with low population density

During global installation of telephones the accent is done on development of networks of the central areas and business centres, so a low populated territories will stand aside. Besides existence areas without telephones is caused by shortage of number capacity .Because of fast growth of quantity of subscribers, and also their needs for reception of services of qualitative telecommunication sharply there is a question on fast overcoming a problem of expansion of capacity of networks.

In low populated territories building of a user's network on a copper or fiber-optical cable is inexpedient, as represents bulky enough facilities demanding, long stage-by-stage introduction and significant capital expenses. The low percent of use of each user's pair on local networks does their inefficient and poorly attractive. Any expansion of a network demands exclusively greater engineering works on cable lines. The lining and the organization of communication lines becomes a challenge, and demands the raised capital expenses in the given district by virtue of its remoteness and geographical features.

For the decision of such problems granting services of a telephony by means of construction of the fixed network of standard CDMA which will allow to guarantee:

- the best ceiling and high carrying capacity at the less number of cellulars in a network, that accordingly reduces terms of construction of a network;

- to reduce capital expenses as the radio access enables to reduce terms of construction of a user's network, to put into its operation so, to reduce times of recovery of outlay more quickly;

- to provide needs of quickly growing suburbs and housing estates, small cities and a sparsely populated countryside without the developed infrastructure of telecommunication;

- to provide transformation in a network of mobile communication if necessary.

Construction of the CDMA segment of a telephone system of the general using for territories with low population density is the purpose of this master's work.

Tasks of of development:

- development of model of the CDMA segment of a network;

-research of characteristics of a segment of a network;

- design of the state of network at different fluctuations of traffic;

- choice of method of optimization of network structure and its adaptation under the concrete forecast;

-development of recommendations at the choice of equipment of base stations, an antenna path, the commutation equipment.

Construction of the CDMA network in area with low population density has the features.

At designing we execute the binding of system to real territory . For this purpose it is necessary to carry out data gathering about the area, a relief, quantity of the population, character of its accommodation, consumer abilities, to make precomputations of expected quantity of subscribers. At calculations of loading the category of area, and activity of subscribers which depends on time of day.

- radiocovering of territory:

It is necessary to define the places of the BTS setting, depending on technical aspects and distributing of subscribers, to provide service by communication of the set territory with the required quality and at the minimum number BTS( at the minimal cost of an infrastructure of a network).

-planning of capacity:

Definition of number of transmitters in everyone cellular, admissible percent of blocking of calls in BTS networks, the prognosis of the traffic and number of subscribers in a network. For maintenance of the telephone traffic which defines necessary quantity of speech channels the equipment should be sufficient to serve calls during the time of most loading.

-process of optimization of parameters of a network:

The analysis of work, changing of a configuration, for example, if during the installation of terminals communication will be absent, the decision of a problem will be installation of the external aerial for example on a mast of the television aerial for maintenance of a steady radio communication of user's phone with base station. (practically the percent of installation of external aerials for such areas makes 30 % from the general number of terminals).

The conclusion and prospects of research

Construction of network CDMA will allow to provide with services of qualitative communication the remote areas. As, even in large city, such as Donetsk where the cable infrastructure is seriously enough developed, great number of potential users are located there where it is difficult to provide their qualitative connection to a network on a telephone line or a fiber-optical cable.Besides it is possible to assume also, that new users will be connected to the given network not only of this area, because of those advantages which are given with this standard .

In the further the model of the given network will be created, such parameters of a network, as real carrying capacity , probability of refusal will be estimated at service, fault tolerance of a network as a whole, optimum quantity of channels for satisfactory work, modeling condition of a network at various percent of congestion. Development of ways of increase of fault tolerance of a network is supposed at increase of congestion.