IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0765016
(2001-01-18)
|
발명자
/ 주소 |
- Ozluturk, Fatih M.
- Lomp, Gary R.
|
출원인 / 주소 |
- Interdigital Technology Corporation
|
인용정보 |
피인용 횟수 :
26 인용 특허 :
155 |
초록
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An improvement for a method and system for tracking a spreading code, used in a code division multiple access (CDMA) system. An input signal has spread-spectrum modulation. The spreading code embedded in the spread-spectrum modulation has a plurality of chips. The input signal is sampled, and half-c
An improvement for a method and system for tracking a spreading code, used in a code division multiple access (CDMA) system. An input signal has spread-spectrum modulation. The spreading code embedded in the spread-spectrum modulation has a plurality of chips. The input signal is sampled, and half-chip offset samples are formed from the sampled input signal. An even set of the half-chip offset samples are grouped into an early set of samples, and an odd set of the half-chip offset samples are grouped into a late set of samples. Each early set of samples is multiplied by spreading codes c(n+1), c(n+2), . . . , c(n+L), to generate a first plurality of products. L is approximately equal to the number of chips of delay between the earliest and latest multipath signals. A first plurality of sums and magnitudes are computed from the first plurality of products. The first plurality of magnitudes are multiplied by a first plurality of weights, to generate a first plurality of weighted-signal values. The first plurality of weighted-signal values are summed to generate an early signal-energy value. Each late set of samples is multiplied by spreading codes c(n-1), c(n-2), . . . , c(n-L), to generate a second plurality of products. A second plurality of sums and magnitudes are computed from the second plurality of products. The second plurality of magnitudes are multiplied by a second plurality of weights, to generated a second plurality of weighted-signal values. The second plurality of weighted-signal values are summed to generate a late signal-energy value. A difference is calculated between the early signal-energy value and the late signal-energy value, thereby producing an error signal.
대표청구항
▼
An improvement for a method and system for tracking a spreading code, used in a code division multiple access (CDMA) system. An input signal has spread-spectrum modulation. The spreading code embedded in the spread-spectrum modulation has a plurality of chips. The input signal is sampled, and half-c
An improvement for a method and system for tracking a spreading code, used in a code division multiple access (CDMA) system. An input signal has spread-spectrum modulation. The spreading code embedded in the spread-spectrum modulation has a plurality of chips. The input signal is sampled, and half-chip offset samples are formed from the sampled input signal. An even set of the half-chip offset samples are grouped into an early set of samples, and an odd set of the half-chip offset samples are grouped into a late set of samples. Each early set of samples is multiplied by spreading codes c(n+1), c(n+2), . . . , c(n+L), to generate a first plurality of products. L is approximately equal to the number of chips of delay between the earliest and latest multipath signals. A first plurality of sums and magnitudes are computed from the first plurality of products. The first plurality of magnitudes are multiplied by a first plurality of weights, to generate a first plurality of weighted-signal values. The first plurality of weighted-signal values are summed to generate an early signal-energy value. Each late set of samples is multiplied by spreading codes c(n-1), c(n-2), . . . , c(n-L), to generate a second plurality of products. A second plurality of sums and magnitudes are computed from the second plurality of products. The second plurality of magnitudes are multiplied by a second plurality of weights, to generated a second plurality of weighted-signal values. The second plurality of weighted-signal values are summed to generate a late signal-energy value. A difference is calculated between the early signal-energy value and the late signal-energy value, thereby producing an error signal. t Abstracts of Japan, vol. 015, No. 003 (E-1019), Jan. 7, 1991 & JP 02 256331 A (Sharp Corp.), Oct. 17, 1990, see abstract. Raymond W. Nettleton, "Spectral Efficiency in Cellular Land-Mobile Communications: A Spread-Spectrum Approach," UMI Dissertation Information Service, (1978), 204 pp. Hossein Al Avi, "Power Control and Interference Management in a Spread-Spectrum Cellular Mobile Radio System," UMI Dissertation Information Services, (1984), 129pp. "Code Division Multiple Access (CDMA)", Franz Josef Hagmanns, Volker Hespelt, 8273 ANT Nachrichtentechnische Berichte (1993) Aug., No. 10, Backnang, DE, pp. 64-71. "CDMA and ATM-zwei Technologien, ein Ziel", 2323 Telcom Report (Siemens) 18 (1995) Maerz/Apr., No. 2, Munchen, DE, pp. 60-63. Zhao Liu et al., "SIR-Based Call Admission Control for DS-CDMA Cellular Systems", IEEE Journal on Selected Areas in Communications, US, IEEE Inc. New York, vol. 12, No. 4, May 1, 1994, pp. 638-644. Pahlavan et al.; "Performance of adaptive matched filter receivers over fading multipath channels;" IEEE vol. 38, No. 12; pp. 2106-2113; Dec. 1990. Giannetti et al.; "Design of an all-digital receiver for narrowband continuous-phase asynchronous CDMA systems;" IEEE; vol. 3; pp. 468-472; May 1993. Braun et al.; "An All-Digital receiver for satellite audio broadcasting signals using trellis coded quasi-orthogonal code-division multiplexing," AEI; vol. 4, No. 1; pp. 23-32; 1993. Rick et al.; "Noncoherent parallel acquisition in CDMA spread spectrum systems;" IEEE; paragraph 1; May 1994. Bernasconi; "Receiver architectures for the down-link in a DS-CDMA mobile system;" IEEE; pp. 51-55; Sep. 1994.
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