Justification of the method and device structure to speed up of gold sequences delay acquisition

摘要

Object of consideration - asynchronous-address systems, using code division of channels. A subject of the analysis - the quasi-orthogonal signals ensembles based on the Gold sequences providing reliable division of channels at influence of imitation interference, signal-like noises and devices of their processing. The analysis purpose - optimization of the Gold sequences delay acquisition procedures, capable to adapt to change of structure of the signals that make up the ensembles. The solution is based on the principles and mathematical models developed by authors: the principle of the fast conversions in Galois fields, algebraic model of representation and structure of fast delay acquisition devices for a subclass of the sequences based on the Gold sequences. The problem arises when using the very long sequences in the conditions of limited time of signal observation, high requirements to reliability and accuracy of synchronization, and also structural secrecy of the considered systems. In these conditions use of the various simplified procedures of fast delay acquisition is limited due to their low energy efficiency, while optimum parallel procedures are too difficult for implementation. The problem significantly becomes complicated when is needed achieve synchronization with a quasi-orthogonal signals ensemble, including signals ensemble with dynamically changeable structure applied in the conditions of influence of signal-like noises. This article is devoted to create of a processing method and model of a delay acquisition devices based on the fast conversions in Galois fields, close by efficiency to the optimum parallel scheme, and capable quickly adapt to use and (or) change of structure of Gold sequence on the basis of which ensembles of quasi-orthogonal signals make up. Key features of the described method of processing are implementation of correlation reception of set of synchronized short sequences samples having identical structure with accumulation of symbols from multiple copies of short sequences received from initial Gold sequence. The used principles of separate synchronization on delay components and fast conversions in Galois fields provide a big variety of options to create a delay acquisition devices providing a compromise between the speed and complexity of delay acquisition as it is reached in the known serial-to-parallel schemes. It is shown that the offered delay acquisition devices model for the considered subclass of signals provides the high level of adaptation to change of a signal structure. The offered versions of the scheme of delay acquisition carry out reception and preprocessing of code sequences in real time that favorably distinguishes them from the known schemes, which are carrying out fast conversions by other methods. In particularly, there are no memory devices for storage of the accepted sample at a detection stage that usually is required at accomplishment of fast conversions by other methods. On the basis of the analysis of essential properties of fast conversions in Galois fields perspectives of additional decrease in time expenditure on delay acquisition of the difficult multicomponent constructions which are based on M-sequences are defined. Presented results will be useful to the specialists who are engaged in design of the asynchronous-address systems using aggregate signals with large base and changeable structure for ensuring protection against influence of signal-like noises.