Method and apparatus for orthogonally overlaying variable chip rate spread spectrum signals
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04B-007/216
H04B-007/204
H04B-001/02
H04J-011/00
H04J-013/00
H04Q-007/00
출원번호
US-0009275
(2008-01-17)
등록번호
US-7505440
(2009-03-17)
발명자
/ 주소
Sun,Feng Wen
Lee,Lin Nan
Karimullah,Khalid
출원인 / 주소
The DIRECTV Group, Inc.
인용정보
피인용 횟수 :
1인용 특허 :
11
초록▼
A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic s
A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.
대표청구항▼
The invention claimed is: 1. A method comprising: encoding a plurality of data streams partitioned from a first data stream using a first code to produce a first plurality of orthogonally encoded data streams, wherein every other bit of the first plurality of orthogonally encoded data streams is in
The invention claimed is: 1. A method comprising: encoding a plurality of data streams partitioned from a first data stream using a first code to produce a first plurality of orthogonally encoded data streams, wherein every other bit of the first plurality of orthogonally encoded data streams is inverted; and encoding a second data stream using the at least one second code to produce a second encoded data stream, wherein the at least one first code and at least one second code are selected according to a criterion relating to prefixes of the at least one first code and the at least one second code, the first plurality of orthogonally encoded data streams being represented by a first data signal having a first bandwidth, and the second encoded data stream being represented by a second data signal having a second bandwidth. 2. A method according to claim 1, further comprising: modulating the combined data stream over a first carrier frequency to generate the first data signal; and modulating the second encoded data stream over a second carrier frequency to generate the second data signal, wherein a ratio of the first bandwidth to the second bandwidth is an even number. 3. A method according to claim 1, further comprising: transmitting the first data signal as an overlay onto the second data signal. 4. A method according to claim 1, wherein the criterion specifies that no first or second code or its complement is a prefix for another first or second code or its complement. 5. A method according to claim 1, wherein the at least one second data signal comprises a plurality of narrow-band signals. 6. A method according to claim 5, wherein the plurality of narrow-band signals are separated in frequency from the first carrier frequency by a value that is based on a chip rate of the narrow-band signals. 7. A method according to claim 1, wherein the first and second codes are selected from a set of Walsh codes, the set of Walsh codes corresponding to a Walsh tree. 8. A method according to claim 7, wherein a first node in the Walsh tree that is common to both the first and second codes is closest to a root of the Walsh tree. 9. An apparatus comprising: an encoder configured to encode a plurality of data streams partitioned from a first data stream using a first code to produce a first plurality of orthogonally encoded data streams; and an inverter configured to invert every other bit of the first plurality of orthogonally encoded data streams, wherein the encoder is further configured to encode a second data stream using the at least one second code to produce a second encoded data stream, wherein the at least one first code and at least one second code are selected according to a criterion relating to prefixes of the at least one first code and the at least one second code, the first plurality of orthogonally encoded data streams being represented by a first data signal having a first bandwidth, and the second encoded data stream being represented by a second data signal having a second bandwidth. 10. An apparatus according to claim 9, further comprising: a modulator configured to modulate the combined data stream over a first carrier frequency to generate the first data signal, and to modulate the second encoded data stream over a second carrier frequency to generate the second data signal, wherein a ratio of the first bandwidth to the second bandwidth is an even number. 11. An apparatus according to claim 9, further comprising: a transmitter configured to transmit the first data signal as an overlay onto the second data signal. 12. An apparatus according to claim 9, wherein the criterion specifies that no first or second code or its complement is a prefix for another first or second code or its complement. 13. An apparatus according to claim 9, wherein the at least one second data signal comprises a plurality of narrow-band signals. 14. An apparatus according to claim 13, wherein the plurality of narrow-band signals are separated in frequency from the first carrier frequency by a value that is based on a chip rate of the narrow-band signals. 15. An apparatus according to claim 9, wherein the first and second codes are selected from a set of Walsh codes, the set of Walsh codes corresponding to a Walsh tree. 16. An apparatus according to claim 15, wherein a first node in the Walsh tree that is common to both the first and second codes is closest to a root of the Walsh tree. 17. A method comprising: receiving an overlay signal including a first data signal of a first bandwidth and a second data signal of a second bandwidth, wherein the first data signal represents a first plurality of orthogonally encoded data streams, and the second data signal represents a second encoded data stream, every other bit of the first plurality of orthogonally encoded data streams being inverted; decoding the first plurality of orthogonally encoded data streams to output a first data stream based on at least one first code; and decoding the second encoded data stream to output a second data stream based on at least one second code, wherein the at least one first code and at least one second code are selected according to a criterion relating to prefixes of the at least one first code and the at least one second code. 18. A method according to claim 17, further comprising: demodulating the first data signal and the second data signal, wherein a ratio of the first bandwidth to the second bandwidth is an even number. 19. A method according to claim 17, wherein the criterion specifies that no first or second code or its complement is a prefix for another first or second code or its complement. 20. A method according to claim 17, wherein the second data signal comprises a plurality of narrow-band signals. 21. A method according to claim 20, wherein the plurality of narrow-band signals are separated in frequency from a first carrier frequency of the first data signal by a value that is based on a chip rate of the narrow-band signals. 22. A method according to claim 17, wherein the first and second codes are selected from a set of Walsh codes, the set of Walsh codes corresponding to a Walsh tree. 23. A method according to claim 22, wherein a first node in the Walsh tree that is common to both the first and second codes is closest to a root of the Walsh tree. 24. An apparatus comprising: a receiver configured to receive an overlay signal including a first data signal of a first bandwidth and a second data signal of a second bandwidth, wherein the first data signal represents a first plurality of orthogonally encoded data streams, and the second data signal represents a second encoded data stream, every other bit of the first plurality of orthogonally encoded data streams being inverted; and a decoder configured to decode the first plurality of orthogonally encoded data streams to output a first data stream based on at least one first code, and to decode the second encoded data stream to output a second data stream based on at least one second code, wherein the at least one first code and at least one second code are selected according to a criterion relating to prefixes of the at least one first code and the at least one second code. 25. An apparatus according to claim 24, further comprising: a demodulator configured to demodulate the first-data signal and the second data signal, wherein a ratio of the first bandwidth to the second bandwidth is an even number. 26. An apparatus according to claim 24, wherein the criterion specifies that no first or second code or its complement is a prefix for another first or second code or its complement. 27. An apparatus according to claim 24, wherein the second data signal comprises a plurality of narrow-band signals. 28. An apparatus according to claim 27, wherein the plurality of narrow-band signals are separated in frequency from a first carrier frequency of the first data signal by a value that is based on a chip rate of the narrow-band signals. 29. An apparatus according to claim 24, wherein the first and second codes are selected from a set of Walsh codes, the set of Walsh codes corresponding to a Walsh tree. 30. An apparatus according to claim 29, wherein a first node in the Walsh tree that is common to both the first and second codes is closest to a root of the Walsh tree.
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