The problem of electromagnetic compatibility (EMS) of cellular systems of various standards, acting in one territory, can arise if working strips of frequencies in the ranges provided for these systems are blocked or the protective interval between them is insufficient. Especially careful research is demanded by a case when one of systems is already developed and functions in the working strips of frequencies allocated for it, and the second is planned to expansion in the same or adjacent territory at deficiency of frequency strips.
Possibility of use in two next cells of a network of the same bearing frequency considerably simplifies so-called frequency planning which is very difficult operation at expansion of a network. If frequency division of channels is applied, it is necessary to paint all networks of frequency used in cells so that in one couple next cells there were no two identical frequency channels. It absolutely not simply is also often connected with considerable material inputs.
where h – duration of a cycle of tests; - coefficient of perfection of the applied mathematical models and perfection of programming (is determined by a ratio of labor inputs of programming of tasks); n=408 – average annual number of cycles of tests; / h - expenses (tekushch on carrying out one cycle of tests (are determined by data of the enterprise) counting on the corresponding unit of time.
According to the Motorola company, one of the leading producers of the equipment for CDMA in one bearing range 25 MHz wide can be placed to 18 channels for networks of mobile communication and about 30 - for the fixed networks (where subscriber terminals do not move in space in process a call. It is a lot of or a little? Let's try to compare CDMA network capacity to network capacity on the basis of AMPS. At first sight, apparently, that for such comparison it is necessary to divide width of the bearing CDMA range (1,25 MHz) into width of one frequency AMPS channel (30 kHz) and to find out, the whether no more turned-out number, than 1
The smallest object of distinction is, its minimum size 0,24mm, a background average, a of object of distinction average, at such of visual work according to norms of Snip23-5-95 illumination has to be not less than 400 lx (for a of work 1-, but indoors illumination only 270 lx that does not satisfy to norm.
The BS EGSM sector antenna has to provide approximately identical strengthening in all directions, including and the direction on BS CDMA. Therefore, reduction of KU of the BS EGSM antenna it is accepted equal 0 dB. The MS antenna is omnidirectional therefore reduction of KU of the CDMA MS antenna it is accepted equal 0 dB.
After a choice of the most essential properties changing the level of the current expenses at creation of NTPR, production, the operation of equipment or the software product which are its result scientific and technical progressiveness of results of NTPR is defined:
Since finding of two at the same time working MS of two different CDMA and EGSM systems is one distance less than a half a meter, - an event very improbable, it is possible to consider that EMS MS of CDMA and EGSM - is provided.
As the standard CDMA broadband, with code division of channels and the transmitter of its BS has the smaller radiated capacity, than the D-AMPS standard BS transmitter, further recommendations, first of all, will belong to control, installation and use of BS of the D-AMPS standard. So, if the inequality is not carried out, it is necessary:
Other shortcomings are big complexity of the equipment and, as a result, quite limited circle of producers. Now base stations for this technology let out firms QUALCOMM, Samsung, Motorola, Lucent Technologies, Nortel and some other. Much more companies let out the subscriber equipment, however too it is less than them, than similar producers for other technologies.