Methods and Apparatus for Multi-Carrier Communications With Variable Channel Bandwidth

Abstract

Methods and apparatus for multi-carrier communication with variable channel bandwidth are disclosed, where the time frame structure and the OFDM symbol structure are invariant and the frequency-domain signal structure is flexible. In one embodiment, a mobile station, upon entering a geographic area, uses a core-band to initiate communication and obtain essential information and subsequently switches to full operating bandwidth of the area for the remainder of the communication. If the mobile station operates in a wide range of bandwidths, the mobile station divides the full range into sub-ranges and adjusts its sampling frequency and its FFT size in each sub-range.

What is claimed is: 
     
         1 . 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 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, 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 signaling, where the core-band is narrower than a smallest possible operating channel bandwidth of the system.