The article investigates the effect of pulse interference on information reception in conditions of episodic synchronization of frames of the physical level of a satellite communication channel with streams of radio pulses of unintended interference. An analytical model of the influence of pulse interference on the reception of information in a satellite communication channel under conditions of episodic synchronization of physical-level frames with pulse interference streams is proposed. Using the example of the DVB family of standards, the combined effect of noise and unintended impulse interference on the conditional error probabilities when receiving a synchro group, the service part of the header and the information part of the frame is shown. Estimates of the average number of frames of the physical level for the duration of the interval of episodic synchronization, the number of intervals of episodic synchronization and the proportion of elementary parcels in the frame exposed to interference, depending on the duration of the pulse interference, are given. It is shown that there are such relations between the duration of the interference pulse and the continuity of the sequence, in which the phenomenon of the episodic synchronization of physical-level frames with the flow of pulse interference has a significant impact on the functioning of the satellite communication channel. The dependences of the probability of erroneous reception of a frame of the physical level of a satellite communication channel on the signal-to-interference ratio at the fixed signal-to-noise ratio and on the duration of the interference pulse are obtained. It has been found that at high signal-to-noise ratios and the duration of the interference correlated with the duration of the service part of the frame, but significantly less than the duration of the frame, the probability of erroneous reception of the frame may be higher than at lower signal-to-noise ratios due to errors when receiving the service part of the frames.
The paper describes the main ways of organizing modern satellite communication systems and the methods of synchronization and transmission of service information used in them, the frame synchronization mechanism from the view point of noise immunity. Based on the analysis, a block diagram of a simulation model is proposed for studying the influence of unintentional interference on the channels of modern satellite communication systems. The proposed model of the impact of non-stationary interference on a satellite communication channel takes into account the effect of interference on symbolic, frame synchronization, mechanisms for extracting frame boundaries, as well as the effect of modern error correction codes. The model allows evaluating the impact of non-stationary interference on both the information and the service side of the frame of modern systems of broadband satellite communications. As an indicator of the noise immunity of a satellite communication channel, there was used probability of frame loss, i.e. frame skipping due to a violation in the frame synchronization system, incorrect allocation of frame boundaries, or the presence of errors in the frame that were not repaired by corrective codes. Using this model, we studied the effect of non-stationary interference of various durations on the information and service parts of the frame, compared the results of the impact of non-stationary interferences of various durations with the effect of white Gaussian noise. It is shown that non-stationary interference, which are short noise pulses that do not affect the information part of the frame due to reparation by correction codes, can significantly reduce the reception quality due to disruption of frame synchronization and distortion of service information about the signal-code structure and frame length.
This article considers the model of impact of non-stationary interference on the satellite communications channels of standard DVB-S and DVB-RCS, and also on the channels with frequency-hopping spread spectrum. The results of the impact of unintentional non-stationary interference on the satellite communications channels, which occurs from stationary and mobile sources of interference with the same average power, were compared. The bit error probability is used as a measure of noise immunity of satellite communications channels. In the article the term time coefficient of the disturbance noise existence was introduced. Its essence is to substantiate the degree of noise energy concentration in some time area of the desired signal. As an indication, characterizing noise immunity of data lines to the influence of unsteady noises the bit-error probability was chosen. It depends on the time coefficient of the disturbance noise existence. In the definite period of time coefficient of the unsteady noise existence for low signal-to-noise ratio they can have a more dangerous effect on data lines with FHSS than the continuous disturbance noise increasing the bit-error possibility.
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