Measurement of spatial signature information in CDMA wireless communication systems

• US 6,466,565 B1
• Filed: 01/15/1999
• Issued: 10/15/2002
• Est. Priority Date: 01/08/1997
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.), Trafficmaster USA, Inc. (Vontier Corp.)
• Inventors: Hilsenrath, Oliver, Wax, Mati, Bar, Abraham
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): BEAMER, TEMICA M
• Application Number:
  US09/231,256
• Time in Patent Office: 1,369 Days
• Field of Search: 370/335, 370/342, 370/441, 370/334, 375/130, 375/140, 455/561, 455/562, 455/456
• US Class Current: 370/342
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01S 1/022 Means for monitoring or calibrating
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting
• CPC Class Codes: H04L 67/04 specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
• CPC Class Codes: H04L 67/51 Discovery or management thereof, e.g. service location protocol [SLP] or web services
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A CDMA receiver for measuring spatial signal information corresponding to several user transmitters comprises a bank of coherent receivers coupled to an antenna array, a bank of signal buffers for recording samples of the received signal data, and a bank of I/Q despreaders for despreading selected signal samples. The receiver also comprises a buffer control circuit for selecting active power control groups in the recorded signal samples for despreading, and a despreader control circuit for selecting PN despreading sequences required to despread the selected power groups. Selected data samples from the signal buffers are fed into the despreaders. The output of the despreaders is a set of spatially correlated I/Q data streams divided into temporal frames, where each frame contains active power control groups from different user transmitters.

Claims

1. A CDMA receiver comprising:

a bank of coherent receivers coupled to an antenna array, wherein the receivers measure signal data from user transmitters;

a bank of signal buffers coupled to the coherent receivers, wherein the buffers record samples of the received signal data;

a bank of I/Q despreaders coupled to the signal buffers, wherein the despreaders despread selected signal samples recorded in the signal buffers and produce a set of spatially correlated I/Q data streams divided into temporal frames, wherein each frame contains active power control groups from different user transmitters;

a buffer control circuit coupled to the signal buffers, wherein the buffer control circuit selects the selected signal samples recorded in the signal buffers; and

a despreader control circuit coupled to the I/Q despreaders, wherein the despreader control circuit selects despreading sequences corresponding to the different user transmitters.

2. The receiver of claim 1 further comprising a microprocessor coupled to the despreader control circuit, wherein the microprocessor computes Walsh codes from transmitter signal information data.

3. The receiver of claim 1 wherein the despreading sequences comprise Walsh codes derived from transmitter signal information data.

4. The receiver of claim 1 further comprising a processor coupled to the I/Q despreaders, wherein the processor computes spatial signatures from the spatially correlated I/Q data streams.

5. The receiver of claim 1 further comprising a processor coupled to the I/Q despreaders, wherein the processor estimates a frequency of the I/Q data streams and corrects a residual frequency error of the I/Q data streams.

6. A method for determining spatial signal information of user transmitters in a CDMA communications system, the method comprising:

coherently receiving at an antenna array signal data from the user transmitters;

recording samples of the received signal data in signal buffers;

selecting selected signal samples recorded in the signal buffers;

selecting despreading sequences corresponding to the different user transmitters;

despreading the selected signal samples using the selected despreading sequences to produce a set of spatially correlated I/Q data streams divided into temporal frames, wherein each frame contains active power control groups from different user transmitters;

estimating a frequency of the I/Q data streams and correcting a residual frequency error of the I/Q data streams; and

computing spatial signatures from the spatially correlated I/Q data streams.

7. The method of claim 6 further comprising computing Walsh codes from transmitter signal information data.

8. The method of claim 6 wherein selecting the despreading sequences comprises selecting Walsh codes.