Transmitter power level optimization and error correction technique

• US 7,398,101 B2
• Filed: 03/01/2005
• Issued: 07/08/2008
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Micrel Incorporated (Microchip Technology Incorporated)
• Inventors: Zinn, Raymond
• Primary Examiner(s): Kumar; Pankaj
• Assistant Examiner(s): Luo; David S
• Application Number:
  US11/070,017
• Publication Number:
  US 20060199602A1
• Time in Patent Office: 1,225 Days
• Field of Search: 455/91, 455/127.1, 455/39, 455/68, 455/69, 455/500, 455/507, 455/517, 455/522
• US Class Current: 455/522
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/48 during retransmission after error or non-acknowledgment

Abstract

A master transceiver automatically lowers its transmit power level at intervals until a slave transceiver no longer accurately receives the transmitted data. When the master detects an inaccurate transfer of data, the master incrementally increases the transmit power level until it is determined that there has been an accurate transfer of data. At that time, the master transmits an acknowledge signal to the slave. Since the automatic power adjust routine is performed using the transmitted data from the master and the error control information transmitted by the slave, there is little or no overhead used by the power adjust routine. Simple control circuitry can be used to carry out the functions.

Claims

1. A technique for adjusting a transmit power level in a master transceiver comprising:

a. transmitting first data by a master transceiver;

b. detecting a transmission from a slave transceiver indicating whether the first data was accurately received by the slave transceiver;

c. if the master transceiver detects that the first data was accurately received by the slave transceiver, then transmitting an acknowledge signal by the master transceiver to the slave transceiver;

d. automatically lowering a transmit power level of the master transceiver;

e. after automatically lowering the transmit power level, transmitting second data by the master transceiver;

f. detecting any transmission from the slave transceiver indicating whether the second data was accurately received by the slave transceiver;

g. if the master transceiver detects that the second data was accurately received by the slave transceiver, then transmitting an acknowledge signal by the master transceiver to the slave transceiver;

h. raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the slave transceiver and retransmitting the second data; and

i. repeating steps f-h until the master transceiver detects that the second data was accurately received by the slave transceiver.

2. The method of claim 1 wherein step d comprises lowering the transmit power level to a minimum level.

3. The method of claim 1 wherein the first transmit power level is adjustable in increments, and wherein step d comprises lowering the transmit power level by at least one power level.

4. The method of claim 1 wherein the first transmit power level is adjustable in increments, and wherein step d comprises lowering the transmit power level by one power level.

5. The method of claim 1 wherein the first transmit power level is adjustable in increments, and wherein step h comprises raising the transmit power level by at least one power level.

6. The method of claim 1 wherein the first transmit power level is adjustable in increments, and wherein step h comprises raising the transmit power level by one power level.

7. The method of claim 1 wherein step f comprises detecting an echo of the second data from the slave receiver.

8. The method of claim 1 wherein step f comprises detecting an error code from the slave receiver.

9. The method of claim 1 wherein step h comprises raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the slave transceiver prior to a timer in the master transceiver timing out and then retransmitting the second data.

10. The method of claim 1 further comprising performing steps d-i only at certain intervals.

11. The method of claim 1 further comprising performing steps d-i if it is detected that the first data was not accurately received by the slave transceiver.

12. The method of claim 1 wherein steps a and e comprise transmitting data by frequency shift keying.

13. The method of claim 1 further comprising:

detecting a receive signal strength indication (RSSI) signal;

wherein step h comprises raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the slave transceiver and that the RSSI signal was below a certain threshold, and then retransmitting the second data.

14. The method of claim 13 wherein step h further comprises:

retransmitting the second data at the transmit power level used in step e if the RSSI signal level was above a certain threshold.

15. The method of claim 13 wherein step h further comprises:

changing a transmit frequency channel if the RSSI signal level was above a certain threshold; and

retransmitting the second data at the transmit power level used in step e.

16. A master transceiver formed as an integrated circuit comprising:

a transmit power amplifier having a variable power output;

a controller for performing various functions including varying the power output of the power amplifier;

the controller being configured to perform the following functions;

a. transmitting first data by the master transceiver;

b. detecting any transmission from a slave transceiver indicating whether the first data was accurately received by the slave transceiver;

c. if the master transceiver detects that the first data was accurately received by the slave transceiver, then transmitting an acknowledge signal by the master transceiver to the slave transceiver;

d. automatically lowering a transmit power level of the master transceiver;

e. after automatically lowering the transmit power level, transmitting second data by the master transceiver;

f. detecting any transmission from the slave transceiver indicating whether the second data was accurately received by the slave transceiver;

g. if the master transceiver detects that the second data was accurately received by the slave transceiver, then transmitting an acknowledge signal by the master transceiver to the slave transceiver;

h. raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the slave transceiver and retransmitting the second data; and

i. repeating steps f-h until the master transceiver detects that the second data was accurately received by the slave transceiver.

17. The master transceiver of claim 16 wherein step d comprises lowering the transmit power level to a minimum level.

18. The master transceiver of claim 16 wherein the first transmit power level is adjustable in increments, and wherein step d comprises lowering the transmit power level by at least one power level.

19. The master transceiver of claim 16 wherein the first transmit power level is adjustable in increments, and wherein step d comprises lowering the transmit power level by one power level.

20. The master transceiver of claim 16 wherein the first transmit power level is adjustable in increments, and wherein step h comprises raising the transmit power level by at least one power level.

21. The master transceiver of claim 16 wherein the first transmit power level is adjustable in increments, and wherein step h comprises raising the transmit power level by one power level.

22. The master transceiver of claim 16 wherein step f comprises detecting one of an echo of the second data from the slave receiver or an error code from the slave receiver.

23. The master transceiver of claim 16 wherein step h comprises raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the slave transceiver prior to a timer in the master transceiver timing out and, in response, retransmitting the second data.

24. The master transceiver of claim 16 further comprising:

a detector for detecting a receive signal strength indication (RSSI) signal;

wherein step h comprises raising the transmit power level of the master transceiver in the event that the master transceiver does not detect that the second data was accurately received by the master transceiver and that the RSSI signal was below a certain threshold, and then retransmitting the second data.

25. The master transceiver of claim 16 wherein step h further comprises:

retransmitting the second data at the transmit power level used in step e if the RSSI signal level was above a certain threshold.

26. The master transceiver of claim 16 wherein step h further comprises:

changing a transmit frequency channel if the RSSI signal level was above a certain threshold; and

retransmitting the second data at the transmit power level used in step e.