Serial cancellation receiver design for a coded signal processing engine

• US 20110182330A1
• Filed: 03/30/2011
• Published: 07/28/2011
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC
• Original Assignee: Rambus Inc.
• Inventors: Narayan, Anand P., Thomas, John K., Olson, Eric S.
• Granted Patent: US 8,374,299 B2
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 2001/70706 using a code tracking loop, e.g. a delay locked loop
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70715 with application-specific features

Abstract

An interference cancelling receiver combines data from multiple paths after aligning to transmitter timing, and uses either an equalizer or a Rake receiver to compute symbol estimates. Interference estimates are generated from the symbol estimates, and multiple interference estimates are combined after re-aligning the interference estimates to receiver timing. At least two segments of symbol estimates are computed for each segment of interference cancelled data.

Various techniques may be employed for controlling the latency and sequencing of these operations, and the subsystems within the canceller may use different processing clock speeds.

Claims

1. A method for generating an interference suppressed signal in a receiver, comprising:

configuring a processor to select at least one input signal to produce one or more selected signals in the receiver;

configuring the processor to determine an order of suppression of the one or more selected signals based at least in part on the strengths of the one or more selected signals; and

configuring the processor to suppress the one or more selected signals from the at least one input signal in the order of suppression to generate the interference suppressed signal.

2. A method for generating an interference suppressed signal in a receiver, comprising:

configuring a processor to determine an order of suppression of one or more input signals based at least in part on their respective strengths; and

configuring the processor to suppress the one or more input signals in the order of suppression to generate an interference suppressed signal.

3. A method for generating an interference suppressed signal in a receiver, comprising:

configuring a processor to suppress one or more input signals based at least in part on their respective strengths to generate an interference suppressed signal.

4. An apparatus configured for generating an interference suppressed signal, comprising:

one or more power estimators configured for computing power estimates of components of a received signal;

a control block coupled to the one or more power estimators configured to determine an order of suppression of the components of a received signal based at least in part on the power estimates; and

one or more processing fingers coupled to the control block configured for generating at least one interference suppressed signal stream.

5. The apparatus recited in claim 4 wherein the one or more processing fingers comprises at least one Hadamard transform module configured to compute the amplitudes of a plurality of channels.

6. The apparatus recited in claim 4, wherein the one or more processing fingers comprises a de-spreader configured for despreading an input signal.

7. A receiver for a wireless communication system, said communication system comprising:

a control processor configured for receiving a signal y having one or more data parameters, said control processor configured for selecting which of the one or more data parameters to send to each of one or more fingers, the one or more fingers comprising at least one search finger and at least one tracking finger;

at least one correlator residing in said at least one tracking finger, said at least one correlator being configured to correlate said signal y with a reference signal s_n; and

a Coded Signal Processing Engine (CSPE) residing in said at least one tracking finger and configured for performing interference suppression in the signal y, said CSPE configured for generating a projection from the signal y, signal y comprising, a spread signal matrix s_i of the source of interest, signals of other interfering sources s₁, s₂, s₃ . . . , s_p; and

noise n.

8. The receiver recited in claim 7, wherein the receiver is further configured to divide the signal y into y_i channel and a y_Q channel.

9. The receiver recited in claim 8, wherein said at least one search finger is configured in the y_i channel to multiply a pilot Walsh code with a short code to generate a first reference signal if the Walsh code is non-zero.

10. The receiver recited in claim 9, wherein said at least one search finger is further configured to multiply the first reference signal by an orthogonal projection matrix to generate a second reference signal with at least one interference signal removed.

11. The receiver recited in claim 10, wherein said at least one search finger is further configured to multiply the second reference signal with the signal y_i to generate an intermediate signal.

12. The receiver recited in claim 11, wherein said at least one search finger is further configured to correlate the intermediate signal by summing the product of y_i and the second reference signal over a correlation length N to generate a first one or more summation signals.

13. The receiver recited in claim 12 wherein in the y_Q channel, said at least one search finger is further configured to multiply a pilot Walsh code with a short code to generate a first reference signal if the Walsh code is non-zero.

14. The receiver recited in claim 13, wherein said at least one search finger is further configured to multiply the first reference signal by a respective orthogonal projection matrix to generate a second reference signal having at least one interference signal removed.

15. The receiver recited in claim 14, wherein said at least one search finger is further configured to multiply the second reference signal with the signal y_Q to generate a second intermediate signal.

16. The receiver recited in claim 15, wherein said at least one search finger is further configured to correlate the second intermediate signal by summing the product of y_Q and the second reference signal over a correlation length N in said summer to generate a second one or more summation signals.

17. The receiver recited in claim 16, wherein said at least one search finger is further configured to process the first one or more summation signals and the second one or more summation signals to select a strongest summation signal.