IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
|
| 국제특허분류(IPC7판) |
|
| 출원번호 |
US-0775969
(2010-05-07)
|
| 등록번호 |
US-8218603
(2012-07-10)
|
|
발명자
/ 주소 |
|
| 출원인 / 주소 |
- InterDigital Technology Corporation
|
| 대리인 / 주소 |
|
| 인용정보 |
피인용 횟수 :
0 인용 특허 :
31 |
초록
▼
A simple and robust CTL is used for time tracking of multipath components of a spread spectrum signal transmitted over a wireless multipath fading channel. A digital code-tracking loop includes the implementations of despreading early and late data samples by use of a pseudonoise sequence, an error
A simple and robust CTL is used for time tracking of multipath components of a spread spectrum signal transmitted over a wireless multipath fading channel. A digital code-tracking loop includes the implementations of despreading early and late data samples by use of a pseudonoise sequence, an error signal output generated by the despreading, and adjustment for a plurality of on-time, early and late samples, a data rate of a control signal provided as a fractional proportion of a data rate of error signals.
대표청구항
▼
1. A receiver, for use in a wireless transmit/receive unit (WTRU), configured to receive a spread spectrum signal over a wireless multipath fading channel, the receiver comprising: a code tracking loop (CTL), the CTL comprising: an input sample selector configured to select an on-time, late, and ear
1. A receiver, for use in a wireless transmit/receive unit (WTRU), configured to receive a spread spectrum signal over a wireless multipath fading channel, the receiver comprising: a code tracking loop (CTL), the CTL comprising: an input sample selector configured to select an on-time, late, and early sample from a plurality of received samples;a late sample pseudo noise (PN) despreader coupled to the input sample selector configured to despread the selected late sample based on a PN sequence known to the receiver;an early sample PN despreader coupled to the input sample selector configured to despread the selected early sample based on the PN sequence known to the receiver;an early and late detector comprising a late power calculator, an early power calculator, and a first summer coupled to the early sample PN despreader and the late sample PN despreader, the early and late detector configured to calculate an error signal based on a despread early sample and a despread late sample;an integrator and dump circuit coupled to the early and late detector, the integrator and dump circuit configured to accumulate N error signals, where N is an integer greater than 1 that indicates a number of error signals calculated in an integration interval;a sign calculator coupled to the integrator and dump circuit configured to calculate the sign but not the magnitude of the accumulated error signals and output the calculated sign as a control signal; anda second summer coupled to the sign calculator and the input sample selector, the second summer configured to: receive the control signal from the sign calculator as a relative timing adjustment and a previous output from the second summer;sum the previous output and the relative timing adjustment to calculate an absolute timing adjustment; andoutput the absolute timing adjustment to the input sample selector. 2. The receiver of claim 1, wherein the late sample is selected one half chip later than the on-time sample, and the early sample is selected one half chip before the on-time sample. 3. The receiver of claim 1, wherein the input sample selector receives an input signal sampled at 16 samples per chip. 4. The receiver of claim 1, wherein the relative timing adjustment has a value of one of +1, 0, or −1. 5. The receiver of claim 1, wherein the input sample selector is configured to adjust the selection of the on-time sample by a fixed magnitude on a condition that the input sample selector receives the absolute timing adjustment from the second summer. 6. The receiver of claim 5, wherein the fixed magnitude is one or two samples. 7. The receiver of claim 5, wherein the input sample selector advances the selection of the on-time sample by the fixed magnitude on a condition that the absolute timing adjustment is less than zero. 8. The receiver of claim 5, wherein the input sample selector delays the selection of the on-time sample by the fixed magnitude on a condition that the absolute timing adjustment is greater than zero. 9. The receiver of claim 1, wherein the integration interval is a pilot symbol interval. 10. A method for use in a receiver for receiving a spread spectrum signal over a wireless multipath fading channel, the method comprising: selecting, via an input sample selector, an on-time, late, and early sample from a plurality of received samples;despreading the selected late sample based on a PN sequence known to the receiver;despreading the selected early sample based on the PN sequence known to the receiver;calculating an error signal based on the despread early sample and the despread late sample;accumulating N error signals, where N is an integer greater than 1 that indicates a number of error signals calculated in an integration interval;calculating the sign of the accumulated error signals and outputting the calculated sign as a control signal; andsumming a previous absolute timing adjustment and the control signal to calculate a current absolute timing adjustment and outputting the absolute timing adjustment to the input sample selector. 11. The method of claim 10, wherein the late sample is selected one half chip later than the on-time sample, and the early sample is selected one half chip before the on-time sample. 12. The method of claim 10, wherein the input sample selector receives an input signal sampled at 16 samples per chip. 13. The method of claim 10, wherein the control signal has a value of one of +1, 0, or −1. 14. The method of claim 10, further comprising adjusting in the input sample selector, the selection of the on-time sample by a fixed magnitude on a condition that the input sample selector receives the absolute timing adjustment. 15. The method of claim 14, wherein the fixed magnitude is one or two samples. 16. The method of claim 14, further comprising advancing the selection of the on-time sample by the fixed magnitude on a condition that when the absolute timing adjustment is less than zero. 17. The method of claim 14, further comprising delaying the selection of the on-time sample by the fixed magnitude on a condition that the absolute timing adjustment is greater than zero. 18. The method of claim 10, wherein the integration interval is a pilot symbol interval.
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