Analysis of M-Sequences Subsets with Joint Fast Delay Acquisition Features

Abstract

The object of consideration is asynchronous address systems using code division of subscribers. The subject of the analysis is quasi-orthogonal signal ensembles based on the M-sequences subset, ensuring a quick change of code sequences structure with a simple implementation of their process device to achieve better protection against the effects of simulation and signal-like interference. The purpose of the analysis is to determine the characteristics of M-sequences subset that have the stated properties of quickly adapting process device to changes in their structure. 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. This article is devoted to create models to mapping a subset of the original M-sequences in the aggregate of short M-sequences, searching for conditions for their joint fast adaptive processing, as well as evaluating the characteristics of the synchronization unit. 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 M-sequence. It is shown that the proposed mapping models, together with offered delay acquisition devices, provide a very high level of device adaptation to changes in the signal structure over a specified range. 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. 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.