Reverse link, transmit power correction and limitation in a radiotelephone system

• US 5,452,473 A
• Filed: 02/28/1994
• Issued: 09/19/1995
• Est. Priority Date: 02/28/1994
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Maloney, John E., Wilson, Nathaniel B., Kerr, Richard J., Kornfeld, Richard K., Weiland, Ana L.
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Charouel, Lisa
• Application Number:
  US08/203,151
• Time in Patent Office: 568 Days
• Field of Search: 330/129, 330/132, 330/136, 455/73, 455/74, 455/67.1, 455/69, 455/70, 455/84, 455/73, 455/88, 455/89, 455/77, 455/115, 455/126, 455/127, 455/245.1, 455/232.1, 455/234.1, 455/234.2, 455/240.1 , 455/246.1, 455/227, 455/177.1, 455/200.1, 375/1, 375/98
• US Class Current: 455/88
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

The process and apparatus of the present invention limits the output power of a radiotelephone, operating in a cellular system in the preferred embodiment. This ensures the transmitted sidebands and synthesizer phase noise remains within a certain specification. This is accomplished by power detection and a correction accumulator that together generate a gain control signal by limiting the gain adjustment to a maximum value, even when the cell site communicating with the radiotelephone is sending power turn-up commands to the radiotelephone. This process includes dynamically correcting the output level of the transmitter due to gain variations in the transmitter stages or gain control elements.

Claims

1. A method for correcting transmit power of a radio device having a plurality of predetermined calibration values and a reference voltage signal, the radio device transmitting and receiving on a plurality of frequencies, each frequency having a frequency index, the method comprising the steps of:

receiving a first signal having a first gain, a first frequency of the plurality of frequencies, and the first frequency having a first frequency index;

determining a receive power value of the first signal;

generating an automatic gain control setpoint in response to the receive power value and the reference voltage signal;

selecting a first predetermined calibration value in response to the automatic gain control setpoint and the first frequency index;

adjusting the first gain in response to the first calibration value;

transmitting a second signal having a second gain and a second frequency of the plurality of frequencies, the second frequency having a second frequency index;

determining a transmit power value of the second signal;

generating a second calibration value in response to the automatic gain control setpoint, the second frequency index, and the transmit power value; and

adjusting the second gain in response to the second calibration value.

2. The method of claim 1 and further including the steps of digitizing the receive power value before generating the automatic gain control setpoint and converting the first predetermined calibration value to an analog value before adjusting the first gain.

3. A radio performing transmit power calibration, the radio transmitting and receiving signals having a plurality of frequencies, each frequency having a frequency index, the radio transmitting signals through a variable gain, transmit amplifier having a control input and receiving signals through a variable gain, receive amplifier having a control input, the radio comprising:

a power detector, coupled to the receive amplifier, for generating a first power value from a received signal having a first frequency;

an integrator, coupled to the power detector, for generating an automatic gain control setpoint from the first power value;

a receive linearizer, coupled to the integrator and the receive amplifier, for generating a receive calibration value in response to the automatic gain control setpoint and a first frequency index corresponding to the first frequency, the receive calibration value being coupled to the receive amplifier control input for adjusting the gain of the receive amplifier;

a second power detector, coupled to the transmit amplifier, for generating a second power value from a transmitted signal having a second frequency; and

a transmit linearizer for generating a transmit calibration value in response to the automatic gain control setpoint, the second power value, and a frequency index corresponding to the second frequency, the transmit calibration value being coupled to the control input of the transmit amplifier for adjusting the gain of the transmit amplifier.

4. A radio performing transmit power calibration, the radio transmitting and receiving signals having a plurality of frequencies, each frequency having a frequency index, the radio transmitting a signal, having a first frequency, through a variable gain transmit amplifier having a control input and receiving a signal, having a second frequency, through a variable gain receive amplifier having a control input, the radio comprising:

a first analog to digital converter, coupled to the receive amplifier, for generating a digital signal from the received signal;

a power detector, coupled to the first analog to digital converter, for generating a power value from the digital signal;

an integrator, coupled to the power detector, for generating an automatic gain control setpoint from the power value;

a receive linearizer, coupled to the integrator, for generating a receive calibration value in response to the automatic gain control set point and a first frequency index corresponding to the second frequency;

a first digital to analog converter, coupled to the receive linearizer, for generating an analog, receive calibration value from the receive calibration value, the analog calibration value coupled to the receive amplifier control input for varying the gain of the receive amplifier;

a second power detector, coupled to the transmit amplifier, for generating an analog power value from the transmitted signal;

a second analog to digital converter, coupled to the second power detector, for generating a digital power value from the analog power value;

a transmit linearizer, coupled to the integrator, for generating a transmit calibration value in response to the automatic gain control setpoint, the digital power value, and a second frequency index corresponding to the first frequency; and

a second digital to analog converter, coupled to the second control input, for generating an analog, transmit calibration value from the transmit calibration value, the analog, transmit calibration value adjusting the gain of the transmit amplifier.