A.E. Kondratenko, V.N. Poddubny

The code multiplexing of radio intercommunication channels regulated by standard IS-95, now is everywhere used in radio communication systems both civil, and military designation. The perspective standard of cellular transmission CDMA 2000 developed on the basis of standard IS-95 which is received in the USA as the military standard starts to take root into practice of a radio communication. Active application by the probable opponent of radio communication systems with a code multiplexing of channels for management of armies and the weapon speaks high parameters of a noise stability, stealthiness, an electromagnetic compatibility and a number of other advantages of these radio communication systems. All this causes necessity of development of the apparatus of an estimation of efficiency of performance of such radio communication systems for conditions of influence of deliberate handicapes for interests of a substantiation of tactic-technical requirements to engineering of their radiosuppression. The purpose of work is determination of dependence of probability of distortion посылок a correcting convolutional code on an input and an output of the decoder of the receiver of a base station of standard IS-95 from the attitude a handicap-signal on a receiver input and a presence of threshold value of this attitude at which reception of the information on a background gaussian interferense is impossible. The problem of a presence of dependence of probability of distortion binary elements a correcting convolutional code on an input of the decoder from the attitude a handicap-signal on a receiver input is solved on the basis of methods of a statistical radio-engineering analytical by. Dependence of probability of distortion of a binary element on an output of the decoder from great values of the attitude a handicap - a signal, in view of parameters of a convolutional code in a backward channel of a communication system of standard IS-95, is received, in view of absence now analytical approaches, a method of mathematical simulation analysis by means of a computer packet of simulation analysis of dynamic systems Simulink from structure of integrated mathematical packet Matlab. The analysis of the received dependences has shown, that at some (threshold) value of the attitude a handicap - a signal, there is a point above which noiseproof encoding only does not improve, and worsens a noise stability of reception of messages. Further it is shown, that threshold value of the attitude a handicap - a signal on a receiver input of M-ary of a signal to which there corresponds crossing two dependences (in the channel and on an output of the decoder), can guaranteed be sampled as factor of suppression. In view of the proved criterion numerical value of factor of suppression of the receiver of a base station of a radio communication system with a code multiplexing of channels of standard IS-95 is received at influence on it gaussian interferense which is necessary for a substantiation of the fundamental requirements to engineering of radiosuppression.