Methods and apparatus for multi-carrier communications with variable channel bandwidth
DC CAFCFirst Claim
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1. A cellular base station, comprising:
- circuitry configured to transmit a broadcast channel in an orthogonal frequency division multiple access (OFDMA) core-band, wherein the core-band is substantially centered at an operating center frequency and the core-band includes a first plurality of subcarrier groups, wherein each subcarrier group includes a plurality of subcarriers, the core-band defined as a frequency segment with a bandwidth that is not greater than a smallest operating channel bandwidth among a plurality of operating channel bandwidths, the core-band having a same value for the plurality of operating channel bandwidths, wherein the circuitry is further configured to maintain a fixed spacing between adjacent subcarriers and to adjust a number of usable subcarriers to realize a variable band, wherein the number of usable subcarriers is determined based on the plurality of operating channel bandwidths; and
circuitry configured to transmit control and data channels using the variable band including a second plurality of subcarrier groups, wherein the variable band includes at least the core-band.
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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.
27 Citations
38 Claims
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1. A cellular base station, comprising:
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circuitry configured to transmit a broadcast channel in an orthogonal frequency division multiple access (OFDMA) core-band, wherein the core-band is substantially centered at an operating center frequency and the core-band includes a first plurality of subcarrier groups, wherein each subcarrier group includes a plurality of subcarriers, the core-band defined as a frequency segment with a bandwidth that is not greater than a smallest operating channel bandwidth among a plurality of operating channel bandwidths, the core-band having a same value for the plurality of operating channel bandwidths, wherein the circuitry is further configured to maintain a fixed spacing between adjacent subcarriers and to adjust a number of usable subcarriers to realize a variable band, wherein the number of usable subcarriers is determined based on the plurality of operating channel bandwidths; and circuitry configured to transmit control and data channels using the variable band including a second plurality of subcarrier groups, wherein the variable band includes at least the core-band. - View Dependent Claims (2, 3, 4, 5)
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6. A variable bandwidth communication method, comprising:
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receiving synchronization information by a cellular mobile station from a base station in an orthogonal frequency division multiple access (OFDMA) core-band, wherein the core-band is substantially centered at an operating center frequency and the core-band includes a first plurality of subcarrier groups where each subcarrier group includes a plurality of subcarriers having a fixed spacing between adjacent subcarriers, wherein a number of usable subcarriers is adjustable to realize a variable band, wherein the number of usable subcarriers is determined based on a plurality of operating channel bandwidths, the core-band defined as a frequency segment with a bandwidth that is not greater than a smallest operating channel bandwidth among the plurality of operating channel bandwidths, the core-band having a same value for the plurality of operating channel bandwidths, wherein the cellular mobile station is configured to operate within the plurality of operating channel bandwidths; synchronizing the cellular mobile station with the base station using the received synchronization information; and receiving control and data channels by the cellular mobile station using the variable band including a second plurality of subcarrier groups, wherein the variable band includes at least the core-band. - View Dependent Claims (7, 8, 9, 10)
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11. A mobile station, comprising:
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circuitry configured to receive broadcast information to access an orthogonal frequency division multiple access (OFDMA) system, wherein the broadcast information is received only in a first band having a first bandwidth and the broadcast information is carried by a plurality of groups of subcarriers with each group having a plurality of contiguous subcarriers; and circuitry configured to determine a second bandwidth of a second band that is associated with the OFDMA system based upon the broadcast information received in the first band, wherein a second bandwidth of the second band is greater than the first bandwidth of the first band, wherein the first band is contained within the second band, wherein a data channel is carried by at least one subcarrier group of the second band, wherein the plurality of contiguous subcarriers have fixed spacing, wherein a number of usable subcarriers is adjustable to realize a variable band, wherein the number of usable subcarriers is determined based on a plurality of operating channel bandwidths, and wherein the first band is defined as a frequency segment with a bandwidth that is not greater than a smallest operating channel bandwidth among the plurality of operating channel bandwidths, the first band having a same value for the plurality of operating channel bandwidths wherein the mobile station is configured to operate within the plurality of operating channel bandwidths. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method performed by a mobile station, comprising:
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receiving broadcast information by the mobile station to access an orthogonal frequency division multiple access (OFDMA) system, wherein the broadcast information is received only in a first band having a first bandwidth and the broadcast information is carried by a plurality of groups of subcarriers with each group having a plurality of contiguous subcarriers; determining a second bandwidth of a second band that is associated with the OFDMA system based upon the broadcast information received in the first band, wherein a second bandwidth of the second band is greater than the first bandwidth of the first band; and based upon the determination of the second bandwidth, receiving the second band, wherein the first band is contained within the second band, wherein a data channel is carried by at least one subcarrier group of the second band, wherein the plurality of contiguous subcarriers have fixed spacing, wherein a number of usable subcarriers is adjustable to realize a variable band, wherein the number of usable subcarriers is determined based on a plurality of operating channel bandwidths, and wherein the first band is defined as a frequency segment with a bandwidth that is not greater than a smallest operating channel bandwidth among the plurality of operating channel bandwidths, the first band having a same value for the plurality of operating channel bandwidths, wherein the mobile station is configured to operate within the plurality of operating channel bandwidths. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification