Method and apparatus for a chip-level no-decision feedback equalizer for CDMA wireless systems

• US 7,477,634 B1
• Filed: 02/09/2006
• Issued: 01/13/2009
• Est. Priority Date: 02/10/2005
• Status: Expired due to Fees

• Current Assignee: Advanced Receiver Technologies, LLC
• Original Assignee: Advanced Receiver Technologies, LLC
• Inventors: McKown, Russell
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): Vu; Michael T
• Application Number:
  US11/350,486
• Time in Patent Office: 1,069 Days
• Field of Search: 370/342, 370/485, 375/232, 375/140, 375/148
• US Class Current: 370/342
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04L 2025/0349 as a feedback filter
• CPC Class Codes: H04L 2025/03605 Block algorithms
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence

Abstract

A method and apparatus for constructing a model of a sampled transmitted CDMA downlink signal comprises receiving a sampled signal at a first module (810), wherein the signal received at the first module has been filtered, receiving despread symbol data for all possible spread codes at a second module (820) from the first module, determining active codes of the possible spread codes in the filtered sampled signal by the second module, receiving from the first module, the despread symbol data identified with the active codes, at a third module (830), providing estimates of a symbol value and a gain based on the symbol data identified with the active codes by the third module, receiving the symbol value and gain estimates from the third module and the active codes from the second module at a fourth module (840), and constructing a model of the sampled transmitted CDMA downlink signal using the symbol value and gain estimates for the active codes by the fourth module.

Claims

1. A method for constructing a model of a sampled transmitted CDMA downlink signal, comprising:

receiving a sampled signal at a first module (810), wherein the signal received at the first module has been filtered;

receiving despread symbol data for all possible spread codes at a second module (820) from the first module;

determining active codes of the possible spread codes in the filtered sampled signal by the second module;

receiving from the first module, the despread symbol data identified with the active codes, at a third module (830);

providing estimates of a symbol value and a gain based on the symbol data identified with the active codes by the third module;

receiving the symbol value and gain estimates from the third module and the active codes from the second module at a fourth module (840); and

constructing a model of the sampled transmitted CDMA downlink signal using the symbol value and gain estimates for the active codes by the fourth module.

2. A method for providing coefficients of a channel equalization filter based on a model of a sampled transmitted CDMA downlink signal, comprising:

receiving the sampled received CDMA downlink signal and the model of the sampled transmitted CDMA downlink signal at a first module (850);

estimating a full-signal channel impulse response based on the sampled received CDMA downlink signal and the model of the sampled transmitted CDMA downlink signal by the first module;

receiving the sampled received CDMA downlink signal by a second module (730);

estimating a pilot-signal channel impulse response based on the sampled received CDMA downlink signal and a well known pilot signal by the second module;

receiving the full-signal channel impulse response from the first module and the pilot-signal channel impulse response from the second module by a third module (860);

selecting between the full-signal channel impulse response and the pilot-signal channel impulse response by the third module;

receiving the selected channel impulse response by a fourth module (740); and

computing the coefficients of a channel equalization filter based on the selected channel impulse response by the fourth module.