Device and method for nodal multiple access into communications channels
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04B-007/212
H04J-003/06
H04B-001/40
출원번호
US-0257864
(2014-04-21)
등록번호
US-9059780
(2015-06-16)
발명자
/ 주소
Godwin, John P.
Chen, Ernest C.
출원인 / 주소
The DIRECTV Group, Inc.
인용정보
피인용 횟수 :
0인용 특허 :
13
초록▼
A nodal division multiple access technique for multiple access to a communications channel such as a satellite transponder. The present invention provides multiple access into a communications channel where each accessing site utilizes one signal from a composite amplitude/phase digital signal const
A nodal division multiple access technique for multiple access to a communications channel such as a satellite transponder. The present invention provides multiple access into a communications channel where each accessing site utilizes one signal from a composite amplitude/phase digital signal constellation, such that demodulators receive the composite signal without changes in the system design related to the multiple access operation.
대표청구항▼
1. A method for multiple access to a communications channel on a satellite comprising the steps of: transmitting a first modulated signal from a first site to a transponder;receiving, from the transponder, a composite signal, the composite signal comprising the first modulated signal and a second mo
1. A method for multiple access to a communications channel on a satellite comprising the steps of: transmitting a first modulated signal from a first site to a transponder;receiving, from the transponder, a composite signal, the composite signal comprising the first modulated signal and a second modulated signal transmitted from at least a second site;modulating the information bit stream with a modulating signal according to a frequency of a carrier of the received composite signal, comprising the steps of: converting said composite signal into in-phase (I) and quadrature (Q) components of the second modulated signal defining a local I/Q coordinate space for signal processing at the first site, wherein said local I/Q coordinate space is determined with respect to a local oscillator reference and the carrier of the received composite signal;determining an location for the I and Q components of the modulated information bit stream according to a distance between signals in said composite signal and a local signal; andmodulating the information bit stream according to the optimum I/Q location and the carrier;transmitting the modulated information bit stream. 2. A method transmitting an information bit stream, comprising: transmitting a first modulated signal from a first site to a transponder;receiving, from the transponder, a composite signal, the composite signal comprising the first modulated signal and a second modulation signal transmitted from at least a second site;modulating the information bit stream with a modulating signal according to a frequency of a carrier of the received composite signal; andtransmitting the modulated information bit stream. 3. The method of claim 2, wherein modulating the information bit stream with the modulating signal according to the carrier of the received composite signal comprises: removing local modulation from the received composite signal according to the carrier of the received composite signal; andgenerating a modified modulated information bit stream at least in part from the received composite signal having the removed local modulation. 4. The method of claim 3, wherein the frequency of the carrier of the received composite signal is determined at least part from a difference of the modified modulated information bit stream and the received composite signal. 5. The method of claim 3, wherein the modified modulated information bit stream is generated based at least in part on a relative motion between the transponder and the first site. 6. The method of claim 5, wherein the modified modulated information bit stream is modified based at least in part upon an estimate of a carrier frequency shift of the received composite signal. 7. The method of claim 5, wherein the estimate of the carrier frequency shift of the received composite signal is determined at least in part according to a time-rate-of-change of a position of the transponder. 8. The method of claim 5, wherein the modified modulated information bit stream is modified based at least in part upon a delay time between the transmission of the first modulated signal and the receiving of the composite signal having the first modulated signal. 9. The method of claim 8, wherein the delay time is estimated at least in part according to a distance between a position of the transponder. 10. The method of claim 9, wherein the transponder is disposed on a satellite in an orbit having orbital parameters and the position of the transponder is determined at least in part from the orbital parameters. 11. The method of claim 2, wherein the modulated information bit stream is transmitted from the first site. 12. An apparatus for transmitting an information bit stream, comprising: a transmitter, disposed at a first site, for transmitting a first modulated signal to a transponder; anda receiver, disposed at the first site, for receiving, from the transponder, a composite signal, the composite signal comprising the first modulated signal and a second modulation signal transmitted from at least a second site;wherein the transmitter further modulates the information bit stream with a modulating signal according to a frequency of a carrier of the received composite signal and transmits the modulated information bit stream. 13. The apparatus of claim 12, wherein the transmitter modulates the information bit stream with the modulating signal according to the carrier of the received composite signal by: removing local modulation from the received composite signal; andgenerating a modified modulated information bit stream. 14. The apparatus of claim 12, wherein the frequency of the carrier of the received composite signal is determined at least part from a difference of the modified modulated information bit stream and the received composite signal. 15. The apparatus of claim 12, wherein the modified modulated information bit stream is generated based at least in part on a relative motion between the transponder and the first site. 16. The apparatus of claim 15, wherein the modified modulated information bit stream is modified based at least in part upon an estimate of a carrier frequency shift of the received composite signal. 17. The apparatus of claim 15, wherein the estimate of the carrier frequency shift of the received composite signal is determined at least in part according to a time-rate-of-change of a position of the transponder. 18. The apparatus of claim 15, wherein the modified modulated information bit stream is modified based at least in part upon a delay time between the transmission of the first modulated signal and the receiving of the composite signal having the first modulated signal. 19. The apparatus of claim 18, wherein the delay time is estimated at least in part according to a distance between a position of the transponder. 20. The apparatus of claim 19, wherein the transponder is disposed on a satellite in an orbit having orbital parameters and the position of the transponder is determined at least in part from the orbital parameters. 21. The apparatus of claim 12, wherein the modulated information bit stream is transmitted from the first site.
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