US4873683A
Expired / Lapsed
US
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TDMA radio system employing BPSK synchronization for QPSK signals subject to random phase variation and multipath fading
Assignee: Motorola Solutions Inc
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Filing: 1987-12-04
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Granted: 1989-10-10
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Expires: 2007-12-04
Abstract
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.
Inventors
- 👤 David E. Borth
- 👤 Chih-Fei Wang
- 👤 Duane C. Rabe
- 👤 Gerald P. Labedz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:54
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04B; H04B7/00; H04B7/24; H04B7/26; H04B7/2643
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
122 words
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.
Claim 2
Dependent Claim
122 words
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.
Claim 3
Dependent Claim
35 words
A quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system in accordance with claim 1 wherein said means for transmitting further comprises means for amplifying the data signal to an output level.
Claim 4
Dependent Claim
39 words
A quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system in accordance with claim 2 wherein said means for transmitting further comprises means for increasing said output level during the synchronizing portion of the data signal.
Claim 5
Independent Claim
124 words
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: 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.
Claim 6
Independent Claim
124 words
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: 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.
Claim 7
Dependent Claim
27 words
A method in accordance with the method of claim 4 wherein said transmitting step further comprises the step of amplifying the data signal to an output level.
Claim 8
Dependent Claim
31 words
A method in accordance with the method of claim 5 wherein said transmitting step further comprises the step of increasing said output level during the synchronizing portion of the data signal.
Claim 9
Dependent Claim
142 words
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: 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.
Claim 10
Dependent Claim
142 words
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: 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.
Claim 11
Dependent Claim
42 words
A quadrature phase shift keying (QPSK) time division multiple access (TDMA) radio system in accordance with claim 1 wherein said means for compensating the multipath distortion and phase variation further comprises means for coherently combining at least two rays of multiple signal.
Claim 12
Dependent Claim
40 words
A quadrature pahse shift keying (QPSK) time division multiple access (TDMA) radio system in accordance with claim 1 wherein said means for compensating the multipath distortion and phase variation further comprises means for algebraically and trigonometrically cancelling the phase variation.
Claim 13
Dependent Claim
35 words
A method in accordance with the method of claim 4 wherein said step of compensating the multipath distortion and phase variation further comprises the step of coherently combining at least two rays of multipath signal.
Claim 14
Dependent Claim
33 words
A method in accordance with the method of claim 4 wherein said step of compensating the multipath distortion and phase variation further comprises the step of algebraically and trigonometrically cancelling the phase variation.
Claim 15
Dependent Claim
37 words
A time division multiple access (TDMA) radio system in accordance with claim 7 wherein said means for compensating the multipath distortion and phase variation further comprises means for coherently combining at least two rays of multipath signal.
Claim 16
Dependent Claim
35 words
A time division multipath access (TDMA) radio system in accordance with claim 7 wherein said means for compensating the multipath distortion and phase variation further comprises means for algebraically and trigonometrically cancelling the phase variation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-09 | 1993-04-10 | 1993-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-09 | 1997-04-10 | 1997-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-09 | 2001-04-10 | 2001-10-10 | $7700.00 | Window Closed / Lapsed |