Cellular communication devices with automated power level adjust

• US 6,018,650 A
• Filed: 12/18/1996
• Issued: 01/25/2000
• Est. Priority Date: 12/18/1996
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Aironet Wireless Communications, Inc. (Cisco Systems, Inc.)
• Inventors: Dollard, Michael S., Petsko, David P.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US08/769,214
• Time in Patent Office: 1,133 Days
• Field of Search: 455/115, 455/127, 455/69, 455/126, 455/67.1, 455/117, 455/234.1, 455/245.1, 330/207 P, 330/279
• US Class Current: 455/234.1
• CPC Class Codes: H04W 52/10 Open loop power control

Abstract

A cellular communication device for a cellular communication network which includes a radio-frequency (RF) transmitter for transmitting an RF signal at an output power level to one or more other devices in the cellular communication network; an RF receiver for receiving an RF signal from one or more other devices in the cellular communication network; and a gain control circuit for sampling the output power level to obtain a sampled output power level signal, digitizing the sampled output power level signal, and adjusting a gain of the RF transmitter based on the digitized sampled output power level signal in order that the output power level of the RF transmitter approaches a predefined output power level. The gain may also be adjusted in response to the Received Signal Strength Indicator (RSSI) in order to conserve battery power.

Claims

1. A cellular communication device for a cellular communication network, comprising:

a radio-frequency (RF) transmitter for transmitting an RF signal at an output power level to one or more other devices in the cellular communication network;

an RF receiver for receiving an RF signal from one or more other devices in the cellular communication network; and

a gain control circuit for sampling the output power level signal, digitizing the sampled output power level signal, computing a gain differential between the sampled output power level signal and a predefined output power level, wherein if the absolute value of the gain differential is greater than a predetermined threshold, a gain of the RF transmitter is then adjusted by an amount substantially equal to the gain differential in order to maintain a substantially constant output level at the RF transmitter corresponding to the predefined output power level.

2. The device of claim 1, wherein the gain control circuit includes a coupler for sampling the output power level.

3. The device of claim 2, wherein the gain control circuit further includes a peak power detector connected to an output of the coupler.

4. The device of claim 2, wherein the gain control circuit further includes an A/D converter for digitizing the sampled output power level signal and a processor for processing the digitized sample.

5. The device of claim 1, wherein the gain control circuit includes means for adjusting a gain of an amplifier included in the RF transmitter.

6. The device of claim 5, wherein the amplifier comprises an amplifier for amplifying an intermediate frequency signal within the RF transmitter.

7. The device of claim 5, wherein the amplifier comprises a power amplifier for amplifying the RF signal transmitted by the RF transmitter.

8. The device of claim 1, wherein the RF transmitter employs frequency hopping techniques and the gain control circuit samples the output power level at approximately each frequency.

9. The device of claim 1, wherein the RF transmitter employs frequency hopping techniques and the gain control circuit samples the output power level at times independent of where the RF transmitter is in a frequency hopping sequence.

10. The device of claim 1, wherein the RF transmitter employs frequency hopping techniques and includes another gain control circuit which adjusts the gain of the RF transmitter based on where the RF transmitter is in a frequency hopping sequence using a set of predetermined gain values.

11. The device of claim 1, wherein the device comprises an antenna at the output of the RF transmitter and a circuit for sensing an amount of output power reflected back into the output of the RF transmitter.

12. The device of claim 11, wherein the circuit for sensing triggers an alarm in the event the reflected power exceeds a predetermined threshold.

13. The device of claim 1, further comprising a circuit for obtaining a received signal strength indicator (RSSI) indicative of the strength of a signal received by the RF receiver, and a circuit for adjusting the predefined output power level based on the RSSI.

14. The device of claim 13, wherein in the event the RSSI exceeds a predetermined threshold, the predefined output power level is set at a value lower than when the RSSI does not exceed the predetermined threshold.

15. The device of claim 1, wherein the device comprises a mobile terminal.

16. The device of claim 1, wherein the device comprises a base station.

17. A method for controlling a cellular communication device for a cellular communication network, wherein the cellular communication device includes a radio-frequency (RF) transmitter for transmitting an RF signal at an output power level to one or more other devices in the cellular communication network, and an RF receiver for receiving an RF signal from one or more other devices in the cellular communication network, the method comprising the steps of:

sampling the output power level to obtain a samples output power level signal, digitizing the sampled output power level signal, computing a gain differential between the sampled output power level signal and a preferred output power level, wherein if the absolute value of the gain differential is greater than a predetermined threshold, a gain of the RF transmitter is then adjusted by an amount substantially equal to the gain differential in order to maintain a substantially constant output power level of the RF transmitter corresponding to the predefined output power level.

18. A radio, comprising:

a radio-frequency (RF) transmitter for transmitting an RF signal at an output power level;

an RF receiver for receiving an RF signal; and

a gain control circuit for sampling the output power level to obtain a sampled output power level signal, digitizing the sampled output power level signal, computing a gain differential between the sampled output power level, wherein if the absolute value of the gain differential is greater than a predetermined threshold, a gain of the RF transmitter is then adjusted by an amount substantially equal to the gain differential in order to maintain a substantially constant output power level of the RF transmitter corresponding to the predefined output power level.