Patent ID: 7864725

Claim:
In a broadband wireless communication system for a multi-user multi-cell environment, a system comprising: one of multiple transmitters configured to transmit overlaying Multi-Carrier (MC) and Direct Sequence Spread Spectrum (DSSS) signals, wherein: the MC signal is modulated on subcarriers in the frequency domain; the DSSS signal is modulated in either the time domain or the frequency domain; the DSSS signal is aligned with a boundary of a MC slot or a MC symbol in the time domain when the DSSS and MC signals are synchronized, or the DSSS signal is arbitrarily placed in the time domain when the DSSS and MC signals are not synchronized; and at least one subcarrier of the MC signal can be energized at a different power level, or not be energized at all, and the DSSS signal is transmitted at a power level significantly lower than that of the MC signal.