Low correlation interleaved QAM sequences

Three low correlation interleaved QAM sequence families are presented here. In a CDMA setting, these sequences have the ability to transport a larger amount of data as well as enable variable-rate signaling on the reverse link. These constructions have the lowest known value of maximum correlation magnitude of any sequence family with the same alphabet. Interleaved canonical family ICQ has period N, normalized maximum correlation parameter thetas macr_max bounded above by lsim a radic N, where a ranges from 1.41 in the 16- QAM case to 2.12 for large M. Each user is enabled to transfer 2m bits of data per period of the spreading sequence. Interleaved selected family ISQ has a lower value of thetas macr_max but permits only (m+ 1)-bit data modulation. The thetas macr_max of sequences in this family is bounded above by lsim a radicN, where a ranges from 1.89 in the case of 64-QAM modulation to 1.99 for large M. The third family is over a quadrature-PAM (Q-PAM) subset of size 2M of the M²-QAM constellation. Interleaved family IP has a lower value of thetas macr_max in comparison with family ISQ, while still permitting (m + 1)-bit data modulation. The thetas macr_max of sequences in this family is bounded above by lsim a radicN, where a ranges from 1.39 in the 16-ary Q-PAM case to 1.72 for large M.