A construction of UD k-ary multi-user codes from (2^m(k-1)+1)-ary codes for MAAC
In this paper, we proposed a construction of a UD k-ary T-user coding scheme for MAAC. We first give a construction of k-ary T^f+g-user UD code from a k-ary T^f-user UD code and a k^±-ary T^g-user difference set with its two component sets D^+ and D^- a priori. Based on the k^±-ary T^g-user difference set constructed from a (2k-1)-ary UD code, we recursively construct a UD k-ary T-user codes with code length of 2^m from initial multi-user codes of k-ary, 2(k-1)+1-ary, ..., (2^m(k-1)+1)-ary. Introducing multi-user codes with higer-ary makes the total rate of generated code A higher than that of conventional code.
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