MULTIPLE ACCESS CODING USING CONVOLUTED SEQUENCES FOR MOBILE RADIO COMMUNICATION SYSTEMS

摘要

FIELD: extended-spectrum multiple access or code-division multiple access communication methods for radiophone communication systems. ^ SUBSTANCE: every user is assigned small number of code words, and scrambling masks possessing chosen properties are used. To this end data characters extended by using orthogonal or bi-orthogonal code words are assigned unique scrambling mask chosen from set of scrambling masks possessing definite correlation properties. Set of scrambling masks is chosen so as to ensure that correlation between modulo two sum of two scrambling masks and any code word is constant irrespective of code word and individual masks used for comparison. In one of alternatives when two masks are summed up using modulo two arithmetic addition, then Walsh transform of this sum enables yielding maximum flat Walsh spectrum. Double-layer coding system for cellular radiophone communication systems using demodulation plus subtraction methods guarantees protection at cellular system layer due to using code key generated in pseudorandom manner for selecting one of scrambling masks common for all mobile stations in particular cell. In addition protection of private channels at individual mobile user layer is ensured due to using encryption key generated in pseudorandom manner prior to scrambling operation. ^ EFFECT: enhanced throughput capacity of code-division multiple access system. ^ 8 cl 11 dwg