Patent ID: 7787431

Claim:
In a variable bandwidth wireless communication system communicating under multiple different communication schemes that each have a different bandwidth, a process performed by a base station of generating an information bearing signal for wireless transmission, the process comprising: utilizing by the base station a number of subcarriers to construct a variable bandwidth wireless channel; utilizing by the base station groups of subcarriers, wherein each group includes a plurality of subcarriers; maintaining a fixed spacing between adjacent subcarriers; adding or subtracting, by the base station, groups of subcarriers to scale the variable bandwidth wireless channel and achieve an operating channel bandwidth; and wherein a core-band, including a plurality of subcarrier groups, substantially centered at an operating center frequency of the different communication schemes, is utilized by the base station as a broadcast channel carrying radio control and operation signalling, where the core-band is substantially not wider than a smallest possible operating channel bandwidth of the system; and wherein the information bearing signal has a primary preamble sufficient for basic radio operation and wherein: the primary preamble is a direct sequence in the time domain with a frequency content confined within the core-band, or is an orthogonal frequency-divisional multiplexing (OFDM) symbol corresponding to a particular frequency pattern within the core-band; and wherein properties of the primary preamble comprise: an autocorrelation having a large correlation peak with respect to sidelobes; a cross-correlation with other primary preambles having a small cross-correlation coefficient with respect to power of other primary preambles; and a small peak-to-average ratio; and wherein a large number of primary preamble sequences exhibit the properties.