System and method for generating signal waveforms in a CDMA cellular telephone system

(22) Date of Deposit; (30) Priority Unionist: 06/25/90 US 543,496 (54) TltulO: System to modulate a signal of the information, modulator for propagation spectrum communications, multiple access transmission system, method for modulating a digital information signal and communications system (71) Klein S. Gilhousen; liwin Roberto Padovani; Undsay A. Weaver, Jr .; Charles E. ' Andrew J. Viterbi

M. Jacobs; Wheatley, III;

(86) International Order:

06/21/91

PCT US 91/04400 (87) International Publication: W092 / 00639 (57) ReSUITIO: A system is described and processed for communication of Information signals by the use of propagation spectrum communication techniques. PN sequences are constructed that establish orthogonality between users in order to reduce mutual interference, allowing for higher capacity and better link performance. With orthogonal PN codes, cross-correlation is zero over a predetermined time interval, resulting in a lack of interference between orthogonal codes, provided only that the time frames of the codes are aligned in time with each other. In an exemplified embodiment, the signals are communicated between a cell site and the mobile units by means of propagation-point communication signals in direct sequence. In the cell / mobile link, link, pilot, synchronization, paging and voice channels are defined. The information communicated through the cell / mobile link channels is generally coded, interleaved, modulated by biphasic bias switch (BPSK) with orthogonal coverage of each BPSK symbol along with quadripastric shift key (OPSK) coverage of the covered symbols . In the mobile link, the link, access and voice channels are defined. The information communicated through the mobile / cell link channels is generally coded. Interleaved, and orthogonally signaled along with QPSK propagation.