Methods and apparatus for use in performing dot product operations for spread spectrum communications

• US 6,654,405 B1
• Filed: 10/19/2000
• Issued: 11/25/2003
• Est. Priority Date: 05/28/1999
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: McDonough, John G.
• Primary Examiner(s): Liu, Shuwang
• Application Number:
  US09/692,845
• Time in Patent Office: 1,132 Days
• Field of Search: 375/130, 375/140, 375/146, 375/147, 375/136, 375/142, 375/150, 370/203, 370/206, 370/209, 370/320, 370/335, 370/441
• US Class Current: 375/130
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/10 Code generation

Abstract

A processing apparatus for use in spread spectrum communications includes a controller, a filter programmed in the controller, and a dot product hardware unit external from the controller having the programmed filter. The controller provides a filter input to receive I and Q pilot symbols and a filter output to provide I and Q pilot symbol estimates based on the I and Q pilot signals. The dot product hardware unit has a first input coupled to receive the I and Q pilot symbol estimates, a second input coupled to receive I and Q data symbols, and an output to provide results of a dot product function between the I and Q pilot symbol estimates and the I and Q data symbols.

Claims

1. A signal processing apparatus suitable for use in direct sequence spread spectrum communications, comprising:

an analog receiver;

a quadrature phase shift keying (QPSK) despreader, including;

an input coupled to receive I and Q samples from the analog receiver;

an output to provide I and Q pilot symbols;

a Walsh uncover unit, including;

an input coupled to receive and I and Q pilot symbols;

an output to provide Walsh uncovered I and Q data symbols;

a controller;

a filter programmed in the controller to provide I and Q pilot symbol estimates based on the I and Q pilot symbols;

a dot product hardware unit external from the controller having the programmed filter; and

the dot product hardware unit including;

a first input coupled to receive the I and Q pilot symbol estimates;

a second input coupled to receive the I and Q data symbols; and

an output to provide results of a dot product function between the I and Q pilot symbol estimates and the I and Q data symbols.

2. The signal processing apparatus according to claim 1, wherein the programmed filter has programmable filter coefficients.

3. The signal processing apparatus according to claim 1, wherein the output of the dot product hardware unit is coupled to an input of the controller.

4. A signal processing apparatus as defined in claim 1, further comprising:

a pilot phase/amplitude filter having an input coupled to the output of the QPSK despreader to receive and filter and I and Q pilot symbols, and having an output coupled to the programmed filter, so that the programmed filter generates I and Q pilot symbol estimates from the I and Q pilot symbols as filtered by the pilot phase/amplitude filter.