Frequency correction in a multi-carrier communication system

A signal processing method for a mobile station that operates within an orthogonal frequency division multiple access (OFDMA) wireless communication system including a plurality of base stations covering a plurality of cells, the method comprising:

• receiving an error detection signal comprising a first error detection signal component from a first base station and a second error detection signal component from a second base station, wherein:
• the first error detection signal component and the second error detection signal component are received within one orthogonal frequency division multiplex (OFDM) symbol in a frame structure having a plurality of frames, wherein each frame is divided into a plurality of subframes, each subframe is divided into a plurality of time slots, and a time slot consists of a plurality of OFDM symbols;
• the first error detection signal component and the second error detection signal component occupy a center portion of a channel bandwidth;
• and
• the first error detection signal component and the second error detection signal component are orthogonal or near-orthogonal to each other;
• producing, based on the received error detection signal, an estimate of a first composite frequency error that exists between the mobile station and the first base station and an estimate of a second composite frequency error that exists between the mobile station and the second base station, wherein both the estimate of the first composite frequency error and the estimate of the second composite frequency error are used by the mobile station for transmitting or receiving signals;
• and
• producing an estimate of a common clock frequency error that exists between the mobile station and the first and the second base stations, the estimate based on factors selected from a group consisting of the received error detection signal, the estimate of the first composite frequency error, and the estimate of the second composite frequency error.

A mobile station that operates within an orthogonal frequency division multiple access (OFDMA) wireless communication system including a plurality of base stations covering a plurality of cells, the mobile station comprising:

• a facility configured for receiving an error detection signal comprising a first error detection signal component from a first base station and a second error detection signal component from a second base station, wherein:
• the first error detection signal component and the second error detection signal component are received within one orthogonal frequency division multiplexing (OFDM) symbol in a frame structure having a plurality of frames, wherein each frame is divided into a plurality of subframes, each subframe is divided into a plurality of time slots, and a time slot consists of a plurality of OFDM symbols;
• the first error detection signal component and the second error detection signal component occupy a center portion of a channel bandwidth;
• and
• the first error detection signal component and the second error detection signal component are orthogonal or near-orthogonal to each other;
• a facility configured for producing, based on the received error detection signal, an estimate of a first composite frequency error that exists between the mobile station and the first base station and an estimate of a second composite frequency error that exists between the mobile station and the second base station, wherein both the estimate of the first composite frequency error and the estimate of the second composite frequency error are used by the mobile station for transmitting or receiving signals;
• and
• a facility configured for receiving a third error detection signal component from the first base station and a fourth error detection signal component from the second base station to facilitate estimation of frequency errors that exist between the mobile station and the first base station or the second base station, wherein the third and the fourth error detection signal components are received via a plurality of pilot subcarriers.

A mobile station that operates within an orthogonal frequency division multiple access (OFDMA) wireless communication system including a plurality of base stations covering a plurality of cells, the mobile station comprising:

• a facility configured for receiving an error detection signal comprising a first error detection signal component from a first base station and a second error detection signal component from a second base station, wherein:
• the first error detection signal component and the second error detection signal component are received within one orthogonal frequency division multiplexing (OFDM) symbol in a frame structure having a plurality of frames, wherein each frame is divided into a plurality of subframes, each subframe is divided into a plurality of time slots, and a time slot consists of a plurality of OFDM symbols;
• the first error detection signal component and the second error detection signal component occupy a center portion of a channel bandwidth;
• and
• the first error detection signal component and the second error detection signal component are orthogonal or near-orthogonal to each other;
• a facility configured for producing, based on the received error detection signal, an estimate of a first composite frequency error that exists between the mobile station and the first base station and an estimate of a second composite frequency error that exists between the mobile station and the second base station, wherein both the estimate of the first composite frequency error and the estimate of the second composite frequency error are used by the mobile station for transmitting or receiving signals;
• and
• a facility configured for producing an estimate of a common clock frequency error that exists between the mobile station and the first and the second base stations, based on factors selected from a group consisting of the received error detection signal, the estimate of the first composite frequency error, and the estimate of the second composite frequency error.

An orthogonal frequency division multiple access (OFDMA) wireless communication system having a plurality of base stations covering a plurality of cells, the system comprising a first base station configured for transmitting a first error detection signal component and a third error detection signal component, and a second base station configured for transmitting a second error detection signal component, wherein:

• the first error detection signal component and the second error detection signal component are transmitted within one orthogonal frequency division multiplexing (OFDM) symbol in a frame structure having a plurality of frames, wherein each frame is divided into a plurality of subframes, each subframe is divided into a plurality of time slots, and a time slot consists of a plurality of OFDM symbols;
• the first error detection signal component and the second error detection signal component occupy a center portion of a channel bandwidth;
• the first error detection signal component and the second error detection signal component are orthogonal or near-orthogonal to each other;
• and
• the third error detection signal component is transmitted via a plurality of pilot subcarriers;
• the first error detection signal component and the second error detection signal component enable a mobile station communicating with the system to:
• produce an estimate of a first composite frequency error that exists between the mobile station and the first base station and an estimate of a second composite frequency error that exists between the mobile station and the second base station, and
• use both the estimate of the first composite frequency error and the estimate of the second composite frequency error for transmitting or receiving signals;
• and
• the third error detection signal component enables a mobile station communicating with the system to facilitate estimation of a frequency error that exists between the mobile station and the first base station.