Method of secure RF ranging under strong multipath reflections

Patent metadata

Field	Value
Publication number	US-9891311-B2
Application number	US-201414446612-A
Country	US
Kind code	B2
Filing date	Jul 30, 2014
Priority date	Jul 30, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A receiver, including: a tuner receiving an input signal; a signal processor configured to process the input signal; an automatic gain control (AGC) controller configured to: initialize the receiver in a low gain state; determine the presence of a signal; and increase the receiver gain to determine if a weak signal is present prior to a strong signal.

First claim

What is claimed is:

1. A receiver, comprising:
a tuner configured to receive an input signal;
a signal processor configured to process the input signal;
an automatic gain control (AGC) controller configured to: initialize the receiver in a low gain state; determine a presence of the input signal; and increase receiver gain to determine if a weak signal is present prior to a strong signal within the input signal.

2. The receiver of claim 1 , wherein the AGC controller is configured to have a ranging mode and a normal communication mode.

3. The receiver of claim 1 , wherein determining the presence of the input signal includes determining that the receiver locks on to the input signal.

4. The receiver of claim 3 , wherein the receiver is configured to increment a lock counter, store a lock position, and store the receiver gain at this lock position.

5. The receiver of claim 4 , wherein the receiver is configured to, after increasing the receiver gain, determine that the receiver gain is less than a maximum receiver gain, search for a lock prior to a current lock, determine that the prior lock is found, increment a lock counter, store a lock position, and store the receiver gain at this lock position.

6. The receiver of claim 4 , wherein the receiver is configured to, after increasing the receiver gain, determine that the receiver gain is less than a maximum receiver gain, search for a lock prior to a current lock, determine that the prior lock is not found, and further increase the receiver gain.

7. The receiver of claim 4 , wherein the receiver is configured to, after increasing the receiver gain, determine that the receiver gain is not less than a maximum receiver gain, lock the receiver to a most recent lock position, set the receiver gain to a most recent receiver gain, and configure the receiver to receive payload data.

8. The receiver of claim 1 , wherein the receiver is configured to determine that the receiver does not lock onto the input signal.

9. The receiver of claim 8 , wherein the receiver is configured to, after increasing the receiver gain, search for a lock, determine that the lock is found, increment a lock counter, store a lock position, and store the gain at this lock position.

10. The receiver of claim 8 , wherein the receiver is configured to, after increasing the receiver gain, search for a lock, determine that the lock is not found, and determine that the increased receiver gain is not less than a maximum receiver gain.

11. The receiver of claim 8 , wherein the receiver is configured to, after increasing the receiver gain, search for a lock, determine that the lock is found, and further increase the receiver gain.

12. A receiver, comprising:
a tuner configured to receive an input signal;
a signal processor configured to process the input signal;
an automatic gain control (AGC) controller configured to: initialize the receiver in a high gain state; lock onto a weak portion of the input signal when the input signal includes both the weak portion and a strong portion, wherein the weak portion is received prior to the strong portion; and maintain receiver gain in a high state to maintain the lock on the weak portion of the input signal.

13. The receiver of claim 12 , wherein the AGC controller is configured to have a ranging mode and a normal communication mode.

14. The receiver of claim 12 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion includes:
determining the receiver is clipping.

15. The receiver of claim 14 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
incrementing a lock counter, storing a lock position and storing the receiver gain at this lock position; and
further decreasing the receiver gain.

16. The receiver of claim 14 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
incrementing a lock counter, storing a lock position, and storing the receiver gain at this lock position;
further decreasing the receiver gain;
determining that the receiver gain is greater than a minimum receiver gain;
determining that a number of locks is greater than zero;
limiting a lock search area; and
further determining if the receiver is clipping.

17. The receiver of claim 14 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
incrementing a lock counter, storing a lock position, and storing the receiver gain at this lock position;
further decreasing the receiver gain;
determining that the receiver gain is greater than a minimum receiver gain;
determining that a number of locks is not greater than zero; and
further determining if the receiver is clipping.

18. The receiver of claim 14 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
incrementing a lock counter, storing a lock position, and storing the receiver gain at this lock position;
further decreasing the receiver gain;
determining that the receiver gain is not greater than a minimum receiver gain;
determining that a number of locks is greater than zero;
locking the receiver to a most recent lock position and setting the receiver gain to a most recent receiver gain; and
configuring the receiver to receive payload data.

19. The receiver of claim 12 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion includes:
determining the receiver is not clipping.

20. The receiver of claim 19 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
incrementing a lock counter, storing a lock position, and storing the receiver gain at this lock position;
determining that a number of locks is greater than zero;
locking the receiver to a most recent lock position and setting the receiver gain to a most recent receiver gain; and
configuring the receiver to receive payload data.

21. The receiver of claim 19 , wherein locking onto the weak portion of the input signal when the input signal includes the strong portion further includes:
searching for a lock;
determining that the lock is found;
determining that a number of locks is greater than zero;
locking the receiver to a most recent lock position and setting the receiver gain to a most recent receiver gain; and
configuring the receiver to receive payload data.

Assignees

• Nxp Bv

Inventors

• Leong Frank Harald Erich Ho Chung
• Koppelaar Arie Geert Cornelius
• Drude Stefan
• Hekstra Andries Peter

Classifications

• H04B1/711

  the interference being multi-path interference · CPC title

• H04B2201/709718

  Determine interference · CPC title

• G01S13/0209

  Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband · CPC title

• H04L7/0087

  Preprocessing of received signal for synchronisation, e.g. by code conversion, pulse generation or edge detection · CPC title

• G01S7/2921 Primary

  based on data belonging to one radar period · CPC title