IP Library Granted Patent US 8,548,107
Granted Patent B1
US 8,548,107 · App. 12/692,789 · Granted Oct 1, 2013

Advanced multi-user detector

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Quick Facts
Patent No.
US 8,548,107
App. No.
12/692,789
Granted
Oct 1, 2013
Kind
B1
Abstract

A method for detecting multi-user signals including conducting a first energy burst detection detecting a first plurality of user signals as a first energy burst, attempting to decode a user signal from the first plurality of signals within the first energy burst, cancelling out a first user signal from the first energy burst if the first user signal is successfully decoded from the first energy burst, determining a second user signal to be discarded if the second user signal is not successfully decoded from the first energy burst, conducting a second energy burst detection detecting a second plurality of signals as a second burst, and iteratively cancelling out the first user signal successfully decoded from the first energy burst from the second energy burst, wherein the second energy burst detection is conducted when all user signals within the first energy burst are either cancelled out or determined to be discarded.

Claims (33)

1. A method for detecting multi-user signals, the method comprising:

detecting a first energy burst including a first plurality of user signals;

attempting to decode a user signal from the first plurality of signals within the first energy burst;

cancelling out a first user signal from the first energy burst if the first user signal is successfully decoded from the first energy burst;

determining a second user signal to be discarded if the second user signal is not successfully decoded from the first energy burst;

detecting a second energy burst including a second plurality of user signals; and

iteratively cancelling out the first user signal successfully decoded from the first energy burst from the second energy burst,

wherein when to conduct the second energy burst is predetermined using statistical information on how often energy burst detections should be made.

2. The method of claim 1 , further comprising conducting adaptive channel estimation detecting a direction of a Doppler shift and Doppler rate to compensate for the Doppler shift and Doppler rate.

3. An apparatus for detecting multi-user signals, the apparatus comprising:

a burst energy detector for detecting a plurality of user signals as an energy burst;

a channel estimator for estimating an amount of Doppler shift and Doppler rate; and

a decoder for attempting to decode a user signal from the plurality of signals within the energy burst;

an iterative interference canceller for iteratively cancelling out successfully decoded user signal from the energy burst,

wherein the iterative interference canceller statically determines whether the energy burst after the successfully decoded user signal is cancelled out should be input into the decoder or the burst energy detector.

4. The apparatus of claim 3 , wherein a user signal is determined to be discarded if the user signal is not successfully decoded from the energy burst.

5. The apparatus of claim 3 , wherein when the energy burst after the successfully decoded user signal is cancelled out should be input into the burst energy detector is predetermined using statistical information on how often energy burst detections should be made.

6. The apparatus of claim 3 , wherein the channel estimator adaptively detects a direction of the Doppler shift and Doppler rate.

7. A method for detecting multi-user signals, the method comprising:

detecting a first plurality of user signals as a first energy burst;

cancelling out a first user signal of the first plurality of user signals from the first energy burst;

detecting a second plurality of signals as a second burst;

determining when to conduct the second energy burst detection using statistical information associated with the frequency of energy burst detections, and wherein the second energy burst detection is conducted based at least in response to the determination; and

cancelling out the first user signal from the second energy burst.

8. The method of claim 7 further comprising decoding the first user signal by performing at least one of an auto-correlation operation and a cross-correlation using a known basis from the first user.

9. The method of claim 7 further comprising:

determining whether the first user signal has been decoded successfully,

wherein the first user signal is cancelled from the first energy burst in response to successfully decoding the first user signal, and

wherein the first user signal is cancelled from the first energy in response to successfully decoding the first user signal.

10. The method of claim 7 further comprising identifying a second user signal of the first plurality of user signals to be discarded.

11. The method of claim 10 , wherein the second user signal is identified in response to failing to successfully decode the second user signal from the first energy burst.

12. The method of claim 7 , wherein the second energy burst detection is conducted when all user signals within the first energy burst are either cancelled or discarded from the first energy burst.

13. The method of claim 7 , further comprising conducting adaptive channel estimation to detect at least one of Doppler shift and Doppler rate.

Assignments (6)
RELEASE OF SECURITY INTEREST IN PATENTS AT REEL 037993/FRAME 0001 Recorded Jun 19, 2024
From: CITIBANK, N.A., AS ADMINISTRATIVE AGENT
To: COMTECH TELECOMMUNICATIONS CORP.; COMTECH EF DATA CORP.; COMTECH MOBILE DATACOM LLC; COMTECH SATELLITE NETWORK TECHNOLOGIES, INC.; COMTECH SYSTEMS, INC.; COMTECH XICOM TECHNOLOGY, INC.; MAPLE ACQUISITION LLC; TELECOMMUNICATION SYSTEMS, INC.
Reel/Frame 067780/0566 →
SECURITY INTEREST Recorded Jun 18, 2024
From: COMTECH MOBILE DATACOM LLC
To: TCW ASSET MANAGEMENT COMPANY LLC, AS AGENT
Reel/Frame 067755/0350 →
CHANGE OF NAME Recorded May 10, 2024
From: COMTECH MOBILE DATACOM CORPORATION
To: COMTECH MOBILE DATACOM LLC
Reel/Frame 067381/0323 →
SECURITY AGREEMENT Recorded Mar 3, 2016
From: COMTECH EF DATA CORP.; COMTECH XICOM TECHNOLOGY, INC.; COMTECH MOBILE DATACOM CORPORATION; TELECOMMUNICATION SYSTEMS, INC.
To: CITIBANK N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 037993/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 3, 2010
From: CRENSHAW, RALPH EUGENE
To: COMTECH MOBILE DATACOM CORPORATION
Reel/Frame 025244/0857 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 1, 2010
From: CANDELL, RICHARD; EBERT, PAUL; FOSSACECA, JOHN; HANDERMANN, GREG; HOLLAND, MARK; JOHNSON, LAJUANA; MCKINLEY, BRUCE L.; WANG, BO
To: COMTECH MOBILE DATACOM CORPORATION
Reel/Frame 024173/0140 →