Method for Interference Estimation for Orthogonal Pilot Patterns
First Claim
1. A method of accurately estimating inter-cell interference in a received signal transmitted in a given sector in an OFDM communication system receiver, comprising, when pilot and data subcarriers are subject to the same interference and the propagation channel is approximately constant across subcarriers spanned by a predetermined number of consecutive pilot signals that are orthogonal across sectors:
- processing the received signal to generate a first set of propagation channel samples that remove the effects of orthogonal pilot patterns;
generating a propagation channel estimate from the first set of propagation channel samples;
processing the received signal to generate a second set of propagation channel samples that include the effects of orthogonal pilot patterns;
estimating inter-cell interference in the received signal by subtracting the propagation channel estimate from the second propagation channel samples.
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Abstract
In an OFDM communications system receiver, channel estimates are processed to remove or reduce noise, exploiting the orthogonality of pilot patterns. The de-noised channel estimates are then used to compute inter-cell interference. The noise effects of orthogonal pilot patterns are selectively removed from channel samples in estimating inter-cell interference, depending on whether data subcarriers are subject to the same interference as pilot subcarriers, and whether data subcarriers are subject to interference from sectors with pilot patterns orthogonal to those in the transmitting sector. A further calculation removes noise from cells not identified by an orthogonal pilot sequence, which may be particularly applicable when large variations exist in the frequency domain of the propagation channel across a pilot pattern.
25 Citations
30 Claims
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1. A method of accurately estimating inter-cell interference in a received signal transmitted in a given sector in an OFDM communication system receiver, comprising, when pilot and data subcarriers are subject to the same interference and the propagation channel is approximately constant across subcarriers spanned by a predetermined number of consecutive pilot signals that are orthogonal across sectors:
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processing the received signal to generate a first set of propagation channel samples that remove the effects of orthogonal pilot patterns; generating a propagation channel estimate from the first set of propagation channel samples; processing the received signal to generate a second set of propagation channel samples that include the effects of orthogonal pilot patterns; estimating inter-cell interference in the received signal by subtracting the propagation channel estimate from the second propagation channel samples. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An OFDM communication system receiver, comprising:
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a receiver operative to receive a signal transmitted in a given sector; a channel estimation circuit operative to detect when pilot and data subcarriers are subject to the same interference and the propagation channel is approximately constant across subcarriers spanned by a predetermined number of consecutive pilot signals that are orthogonal across sectors, and to process the received signal to generate a first set of propagation channel samples that remove the effects of orthogonal pilot patterns; generate a propagation channel estimate from the first set of propagation channel samples; process the received signal to generate a second set of propagation channel samples that include the effects of orthogonal pilot patterns; and estimate inter-cell interference in the received signal by subtracting the propagation channel estimate from the second propagation channel samples. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification