Parallel interference cancellation receiver for multiuser detection of CDMA signals
First Claim
1. An interference canceller for use in a receiver that separates received communication signals (r) from a plurality of transmitters over a CDMA interface into a plurality of desired signals (d(k)), the interference canceller comprising:
- a channel estimation processor for receiving the communication signals (r) producing individual impulse response estimates (A) for the plurality of desired signals (d(k)), said impulse response estimates coupled to a data estimation and interference canceller; and
said data estimation and interference canceller receiving the communication signals (r) and said impulse response estimates (A) and outputting the plurality of desired signals (d(k)).
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Accused Products
Abstract
A parallel interference cancellation receiver that reduces impulse response interference using a model of the received signal similar to that used in block linear equalizers. Block linear equalizers comprise decorrelating receivers, zero-forcing receivers, minimum mean square error receivers and the like. The invention comprises an interference computation processor feedback loop for correcting the output of a direct interference canceller. The m iterative process removes interferers from the output symbols of a matched-filter. The PIC receiver uses received signal models of the various block linear equalizers that do not assume that each subchannel consists of several distinct paths. The receiver estimates the impulse response characteristic of each subchannel as a whole.
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Citations
63 Claims
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1. An interference canceller for use in a receiver that separates received communication signals (r) from a plurality of transmitters over a CDMA interface into a plurality of desired signals (d(k)), the interference canceller comprising:
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a channel estimation processor for receiving the communication signals (r) producing individual impulse response estimates (A) for the plurality of desired signals (d(k)), said impulse response estimates coupled to a data estimation and interference canceller; and
said data estimation and interference canceller receiving the communication signals (r) and said impulse response estimates (A) and outputting the plurality of desired signals (d(k)). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for separating received signals (r) from a plurality of transmitters over a CDMA interface into a plurality of desired signals (d(k) ), comprising the steps of:
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a) creating a total system response matrix(A) from impulse response estimates (h(k)) from the received signals (r);
b) filtering the received signals (r) with said total system response matrix (A) producing estimates of the desired signals with selective signals (y);
c) choosing a receiver structure (O) to converge to;
d) deriving an S matrix from said receiver structure;
e) deriving a T matrix from said receiver structure;
f) scaling said filter output (y) as desired signal estimates (d(m)) by multiplying by said matrix S;
g) computing interference estimates (c(m)) by multiplying said scaled output (d(m)) by said matrix T;
h) subtracting (z(m)) said interference estimates (c(m)) from said filter output (y);
i) scaling said filter output minus said interference estimates (z(m)) as desired signal estimates (d(m)) by multiplying with said matrix S;
j) repeating steps g) through i) for m iterations; and
k) outputting said desired signal estimates (d(m)) as the plurality of desired signals (d(k)) absent said selective signals. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63)
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Specification