A system and method for communicating information signals using spread spectrum
communication techniques. PN sequences are constructed that provide orthogonality
between the users so that mutual interference will be reduced, allowing higher
capacity and better link performance. With orthogonal PN codes, the cross-correlation
is zero over a predetermined time interval, resulting in no interference between
the orthogonal codes, provided only that the code time frames are time aligned
with each other. In an exemplary embodiment, signals are communicated between a
cell-site and mobile units using direct sequence spread spectrum communication
signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are
defined. Information communicated on the cell-to-mobile link channels are, in general,
encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering
of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the
covered symbols. In the mobile-to-cell link, access and voice channels are defined.
Information communicated on the mobile-to-cell link channels are, in general, encoded,
interleaved, orthogonal signaling along with QPSK spreading.