Method of compensating phase shift keying frequency offset

Claim 1

A method of communication including a method of compensating frequency offset in a digital mobile communication system having a differential detection scheme as a demodulation method for demodulating a received digital phase shift keying signal having information encoded in M information phases wherein M is equal to 2 N (N is an integer larger than zero) to produce a detected signal, said method comprising the steps of: detecting said received digital phase shift signal; raising the detected digital signal to M-th power (M is the number of information phases) producing M-th power signals to remove a modulation factor from said received signal; accumulating the M-th power signals for N symbols and deriving a phase component of the accumulated M-th power signal; dividing the derived phase component into M so as to obtain an estimation value with respect to phase shift due to the frequency offset which represents frequency deviation from a true carrier frequency contained in the received signal; multiplying the received signal by the obtained estimation value in a form of a conjugate complex number to remove phase shift due to frequency offset from the received signal; and demodulating the resultant signal and providing said digital phase shift keying signal to an output device from which keyed information therein can be retrieved.

Claim 2

A method of communication including a method of compensating frequency offset in a digital mobile communication system having a differential detection scheme as a demodulation method for demodulating a received digital phase shift keying signal having information encoded in M information phases wherein M is equal to 2 N (N is an integer larger than zero) to produce a detected signal, said method comprising the steps of: detecting said received digital phase shift signal; raising the detected digital signal to M-th power (M is the number of information phases) producing M-th power signals to remove a modulation factor from said received signal; accumulating the M-th power signals for N symbols and deriving a phase component of the accumulated M-th power signal; dividing the derived phase component into M so as to obtain an estimation value with respect to phase shift due to the frequency offset which represents frequency deviation from a true carrier frequency contained in the received signal; multiplying the received signal by the obtained estimation value in a form of a conjugate complex number to remove phase shift due to frequency offset from the received signal; and demodulating the resultant signal and providing said digital phase shift keying signal to an output device from which keyed information therein can be retrieved.

Claim 3

A method of communication comprising, the steps of: at a transmitting side, differentially encoding an information data sequence to be transmitted as a digital phase shift keying signal having M information phases wherein M is equal to 2 N (N is an integer larger than zero) and transmitting said encoded information; at a receiving side, receiving and detecting said transmitted digital phase shift keying signal; raising the detected digital signal to M-th power (M is the number of information phases) producing M-th power signals to remove a modulation factor from the received signal; accumulating the M-th power signals for N symbols and deriving a phase component of the accumulated M-th power signal; dividing the derived phase component into M so as to obtain an estimation value with respect to phase shift due to the frequency offset which represents frequency deviation from a true carrier frequency contained in the received signal; multiplying the received signal by the obtained estimation value in a form of a conjugate complex number to remove phase shift due to frequency offset from the received signal; and demodulating the resultant signal and providing said digital phase shift keying signal to an output device from which keyed information therein can be retrieved.

Claim 4

A method of communication comprising, the steps of: at a transmitting side, differentially encoding an information data sequence to be transmitted as a digital phase shift keying signal having M information phases wherein M is equal to 2 N (N is an integer larger than zero) and transmitting said encoded information; at a receiving side, receiving and detecting said transmitted digital phase shift keying signal; raising the detected digital signal to M-th power (M is the number of information phases) producing M-th power signals to remove a modulation factor from the received signal; accumulating the M-th power signals for N symbols and deriving a phase component of the accumulated M-th power signal; dividing the derived phase component into M so as to obtain an estimation value with respect to phase shift due to the frequency offset which represents frequency deviation from a true carrier frequency contained in the received signal; multiplying the received signal by the obtained estimation value in a form of a conjugate complex number to remove phase shift due to frequency offset from the received signal; and demodulating the resultant signal and providing said digital phase shift keying signal to an output device from which keyed information therein can be retrieved.