INTERFERENCE CANCELLATION FOR WIRELESS COMMUNICATIONS
First Claim
1. A method for recovering data from a received signal comprising a first user pilot and an interference signal, the method comprising:
- estimating the pilot from the received signal to generate a first-pass pilot estimate;
cancelling the first-pass pilot estimate from the received signal to generate a first cancelled signal;
estimating the interference signal from the first cancelled signal to generate an interference estimate;
cancelling the interference estimate from the first cancelled signal to generate an interference-cancelled signal;
re-estimating the pilot from the interference-cancelled signal to generate a second pilot estimate; and
demodulating a signal derived from the received signal using the second pilot estimate to recover data from the received signal.
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Abstract
Techniques for improving the capacity of a wireless communications system using interference cancellation (IC). In an early decoding and IC aspect, a frame transmitted from a user to a base station may be decoded prior to the entire frame being received by the base station. The remaining portion of the frame may then be re-constructed at the base station prior to its reception, and cancelled from the receive signal to reduce the interference to frames received from other users. In a power control aspect for early decoding and IC, the power control target level at a local base station may be adjusted in response to successfully early decoding a frame, without affecting the overall outer loop power control operation. Further aspects include late decoding techniques for utilizing the IC of other users'"'"' signals to improve the probability of decoding a given user'"'"'s frames, as well as techniques for traffic channel demodulation using channel re-estimation.
138 Citations
28 Claims
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1. A method for recovering data from a received signal comprising a first user pilot and an interference signal, the method comprising:
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estimating the pilot from the received signal to generate a first-pass pilot estimate; cancelling the first-pass pilot estimate from the received signal to generate a first cancelled signal; estimating the interference signal from the first cancelled signal to generate an interference estimate; cancelling the interference estimate from the first cancelled signal to generate an interference-cancelled signal; re-estimating the pilot from the interference-cancelled signal to generate a second pilot estimate; and demodulating a signal derived from the received signal using the second pilot estimate to recover data from the received signal. - View Dependent Claims (2, 3, 4, 5)
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6. A method for recovering data from a received signal comprising a first user pilot and an interference signal, the method comprising:
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estimating the first user pilot from the received signal to generate a first-pass pilot estimate; cancelling the first-pass pilot estimate from the received signal to generate a first cancelled signal; re-estimating the first user pilot from a signal derived from the first cancelled signal to generate a second pilot estimate; demodulating a signal derived from the received signal using the second pilot estimate to recover data of the first user from the received signal; and if the data is successfully recovered;
reconstructing the first user pilot based on the successfully decoded data, and cancelling the reconstructed first user pilot from the received signal. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An apparatus for recovering data from a received signal comprising a first user pilot and an interference signal, the apparatus comprising:
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a first-pass and residual pilot estimation/reconstruction block configured to; generate a first-pass estimate of the first user pilot; cancel the first-pass estimate from the received signal to generate a first cancelled signal; estimate the interference signal from the first cancelled signal to generate an interference estimate; cancel the interference estimate from the first cancelled signal to generate an interference-cancelled signal; and generate a second estimate of the first user pilot by re-estimating the pilot of the first user from the interference-cancelled signal; and a demodulator configured to demodulate a signal derived from the received signal using a second estimate of the first user pilot to recover data of the first user from the received signal. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An apparatus for recovering data from a received signal comprising a first user pilot and an interference signal, the apparatus comprising:
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a first-pass and residual pilot estimation/reconstruction block configured to; generate a first-pass estimate of the first user pilot; cancel the first-pass estimate from the received signal to generate a first cancelled signal; and re-estimate the first user pilot from a signal derived from the first cancelled signal to generate a second pilot estimate; and a demodulator configured to demodulate a signal derived from the received signal using the second pilot estimate to recover first user data from the received signal; and the first-pass and residual pilot estimation/reconstruction block further configured to, if the data is successfully recovered;
reconstruct the first user pilot based on the successfully decoded data, and cancel the reconstructed first user pilot from the received signal. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. An apparatus for recovering data from a received signal comprising a first user pilot and an interference signal, the apparatus comprising:
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means for performing first-pass pilot interference cancellation of a first user'"'"'s pilot on the received signal to generate a first cancelled signal; means for estimating and cancelling the interference signal from the first cancelled signal to generate an interference-cancelled signal; and means for demodulating a signal derived from the received signal using a re-estimated first user pilot to recover first user data from the received signal.
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26. An apparatus for recovering data from a received signal comprising a first user pilot and an interference signal, the apparatus comprising:
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means for performing first-pass pilot interference cancellation of a first user'"'"'s pilot on the received signal to generate a first cancelled signal; means for demodulating a signal derived from the received signal using a re-estimated first user pilot to generate a second pilot estimate to recover data of the first user from the received signal; and means for, if the data is successfully recovered;
reconstructing the first user pilot based on the successfully decoded data, and cancelling the reconstructed first user pilot from the received signal.
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27. A computer program product for recovering data from a received signal comprising a first user pilot and an interference signal, the product comprising:
computer-readable medium comprising; code for causing a computer to perform first-pass pilot interference cancellation of a first user'"'"'s pilot on the received signal to generate a first cancelled signal; code for causing a computer to estimate and cancel the interference signal from the first cancelled signal to generate an interference-cancelled signal; and code for causing a computer to demodulate a signal derived from the received signal using a re-estimated first user pilot to recover first user data from the received signal.
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28. A computer program product for recovering data from a received signal comprising a first user pilot and an interference signal, the product comprising:
computer-readable medium comprising; code for causing a computer to perform first-pass pilot interference cancellation of a first user'"'"'s pilot on the received signal to generate a first cancelled signal; code for causing a computer to demodulate a signal derived from the received signal using a re-estimated first user pilot to generate a second pilot estimate to recover data of the first user from the received signal; and code for causing a computer to, if the data is successfully recovered;
reconstruct the first user pilot based on the successfully decoded data, and cancel the reconstructed first user pilot from the received signal.
Specification