Spreading code structure for ultra wide band communications

• US 7,388,899 B2
• Filed: 03/24/2003
• Issued: 06/17/2008
• Est. Priority Date: 03/10/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Yamaguchi, Hirohisa
• Primary Examiner(s): Odom; Curtis B.
• Application Number:
  US10/395,580
• Publication Number:
  US 20040179580A1
• Time in Patent Office: 1,912 Days
• Field of Search: 375130-153, 375346-350
• US Class Current: 375/141
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence
• CPC Class Codes: H04B 1/7183 Synchronisation
• CPC Class Codes: H04J 13/004 Orthogonal

Abstract

The ultra wide band communication system of the present invention includes a transmitter (station) and a receiver (station). The transmitter and the receiver employ spreading code comprised of code groups, which respectively comprise varied, auto-correlated codes. Consecutive information bits are spread and de-spread with differing code and the code groups are correlated with each other (e.g., orthogonal) so as to reduce channel impulse response estimation noise. At the receiver, subsequent channel estimates can be added or averaged with an initial channel estimate so as to reduce the channel impulse response estimation noise and thereby provide a relatively more accurate channel response.

Claims

1. A method of resolving a received signal comprising:

matching a received signal to an incoming impulse signal shape, wherein the received signal comprises at least a transmitted signal along with a number of multipath signals;

sampling the received signal;

multiplying the sampled, received signal with de-spreading code;

adding products of the received signal and the de-spreading code to obtain an initial channel estimate;

obtaining subsequent channel estimates for a number of subsequent code groups; and

averaging the initial channel estimate with the subsequent channel estimates to reduce estimation noise;

wherein the number of subsequent channel estimates used to reduce estimation noise is equal to a maximum channel impulse response time divided by an impulse interval.

2. The method of claim 1, wherein the de-spreading code is comprised of code groups that individually comprise varied, auto-correlated codes.

3. The method of claim 2, wherein the code groups are orthogonal to each other.

4. An ultra wide band communication system for low power, high data rate operation, the system comprising:

means for matching a received signal to an incoming impulse signal shape, wherein the received signal comprises at least a transmitted signal along with a number of multipath signals;

means for sampling the received signal;

means for multiplying the sample, received signal with de-spreading code;

means for adding products of the received signal and the de-spreading code to obtain an initial channel estimate;

means for obtaining subsequent channel estimates for a number of subsequent code groups; and

means for averaging the initial channel estimate with the subsequent channel estimates to reduce estimation noise;

wherein the number of subsequent channel estimates used to reduce estimation noise is equal to a maximum channel impulse response time divided by an impulse interval.

5. The system of claim 4, wherein the de-spreading code is comprised of code groups that individually comprise varied, auto-correlated codes.

6. The system of claim 5, wherein the code groups are orthogonal to each other.

7. The system of claim 4, wherein the system has a maximum path delay of more than 100 nsec.

8. The system of claim 4, wherein the system comprises a mobile communication device.

9. The system of claim 4, wherein a distance between said means for sampling and a transmitter used to transmit said received signal is less than about 40 meters.