TDMA radio system employing BPSK synchronization for QPSK signals subject to random phase variation and multipath fading
First Claim
1. A quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system conveying a data signal comprising a synchronizing portion and a message portion in a timeslot over a radio channel which introduces multipath distortion and phase variation in the data signal, the system comprising:
- means for transmitting a synchronizing portion consisting of a plurality of data bits in a predetermined pattern in only one vector of the data signal;
means for receiving the data signal subjected to multipath distortion and phase variation; and
means, responsive to said one vector synchronizing portion of a received data signal, for compensating the multipath distortion and phase variation of the message portion of said received data signal for the duration of one TDMA timeslot.
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Abstract
A time division multiple access (TDMA) radio system conveying a quadrature phase shift keying (QPSK) modulated data signal is disclosed. In order to overcome multipath distortion and phase variation introduced by the radio channel, a synchronizing poriton of a TDMA timeslot is transmitted in only one vector of the QPSK modulation. The system utilizes the one vector synchronizing portion to develop a channel profile estimate which is applied to the received message portion of the QPSK data signal to compensate for the multipath distortion and phase variation during one TDMA timeslot.
46 Citations
13 Claims
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1. A quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system conveying a data signal comprising a synchronizing portion and a message portion in a timeslot over a radio channel which introduces multipath distortion and phase variation in the data signal, the system comprising:
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means for transmitting a synchronizing portion consisting of a plurality of data bits in a predetermined pattern in only one vector of the data signal; means for receiving the data signal subjected to multipath distortion and phase variation; and means, responsive to said one vector synchronizing portion of a received data signal, for compensating the multipath distortion and phase variation of the message portion of said received data signal for the duration of one TDMA timeslot. - View Dependent Claims (2, 3, 8, 9)
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4. A method of conveying, by way of a quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system, a data signal comprising a synchronizing portion and a message portion in a timeslot over a radio channel which introduces multipath distortion and phase variation in the data signal, comprising the steps of:
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transmitting a synchronizing portion consisting of a plurality of data bits in a predetermined pattern in only one vector of the data signal; receiving the data signal subjected to multipath distortion and phase variation; and compensating, in response to said one vector synchronizing portion of a received data signal, the multipath distortion and phase variation of the message portion of said received data signal for the duration of one TDMA timeslot. - View Dependent Claims (5, 6, 10, 11)
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7. A time division multiple access (TDMA) radio system having at least one radio coverage area served by a fixed site transmitter conveying a qaudrature phase shift keying (QPSK) modulated data signal comprising a synchronizing portion and a message portion in at least one TDMA timeslot over a radio channel which introduces multipath distortion and phase variation in the data signal to a receiver, the system comprising:
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means for transmitting a synchronizing portion consisting of a plurality of data bits in a predetermined pattern in only one vector of the data signal; means for receiving the data signal subjected to mutlipath distortion and phase variation; and means, responsive to said one vector synchronizing portion of a received data signal, for compensating the multipath distortion and phase variation of the message portion of said received data signal for the duration of one TDMA timeslot. - View Dependent Claims (12, 13)
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Specification