Study On NHZ/LHZ Frequency Hopping Sequence In The Quasi-synchronous CDMA System

Frequency hopping(FH) communication is commonly used as a spread-spectrumcommunication technology. The ability of anti-MAI and anti-interference ofconventional frequency hopping communication system are directly determined by themerits of the hopping sequence Hamming correlation properties.Capacity by morethan the size and extent of the merits of the communication system performance arealso directly determined by the merits of the hopping sequence Hamming correlationproperties.Hamming correlation low/zero collision area(LHZ/NHZ) in a frequencyhopping sequence associated with the region and even desirable quasi-ideal, so it canbe applied as address codes quasi-synchronous FH-CDMA system, to reduce or eveneliminate multipath interference and influence caused by the communication system,in order to achieve the purpose of improving system performance. This paper focuseson the two-dimensional frequency shift delay Low/zero impact area (TF-LNZ/NHZ)frequency hopping sequence theory and construction methods were studied, the mainresults are as follows：Firstly, several existing No Hit Zone/Low Hit Zone were hopping sequence setexamples, based on interleaving method and the family as the prime digital addresscode improvements are now intertwined Some interleaving method to construct NHZhopping sequence set method.Secondly, the two-dimensional Time delay and Frequency shift No Hit Zoneexisting constructor hopping sequences were studied, we propose a new TF-NHZbased on this method using shift intertwined constructor hopping sequence set, andbased on this method of constructing frequency hopping sequence set on aconstruction method has been improved, so that the improved frequency hoppingsequence set can be achieved under certain conditions and parameters theory moreflexible.Finally, the expansion of low hopping zone(LHZ) concept to two dimensions,constructed time delay and frequency shift low hit zone, gives the definition ofTF-LHZ hopping sequence set. Based on the study LHZ hopping sequence set theory, based on the number of frequency gap deduced sequence length, number sequences,time-frequency constraint relationship between the parameters of low collision zonewidth, the establishment of a theoretical TF-LHZ hopping sequence set community,and gives two methods about constructing hopping sequence.