Methods and apparatus for multi-carrier communications with variable bandwidth channel

A process for generating a signal carrying information for wireless transmission in a wireless communication system of variable bandwidth capable of operating under multiple schemes different communication that each has a different bandwidth, the wireless communications system comprising a plurality of cells, wherein each cell coverage is provided by a base station to distribute or collect information from mobile stations, the process performing the steps of: using a specified number of subcarriers to construct a channel with a particular bandwidth; determine the subchannels including subcarriers groups; provide a structure of time-domain signal, including the length of the symbol; maintain a substantially constant ratio between a sampling frequency (fs) and a size of Fast Fourier Transform, FFT and Fast Fourier Transform, IFFT, signal, or a fixed spacing between adjacent subcarriers; add or subtract some of the subcarriers or subchannels to scale the channel and achieve a bandwidth required for the current communication scheme; and wherein a core band substantially centered at a center frequency of operation of the communication scheme is used to radio control and signaling operation, where the core band is wider than a bandwidth channel operation as small as possible system, wherein generating the signal carrying the information comprises generating the signal carrying the information that has sufficient primary preamble for operation basic radio including synchronization and cell identification, and wherein the preamble primary is an OFDM symbol corresponding to a particular frequency pattern within the core web.