WO2005002074A1 - Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments - Google Patents

Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments Download PDF

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Publication number
WO2005002074A1
WO2005002074A1 PCT/US2004/014100 US2004014100W WO2005002074A1 WO 2005002074 A1 WO2005002074 A1 WO 2005002074A1 US 2004014100 W US2004014100 W US 2004014100W WO 2005002074 A1 WO2005002074 A1 WO 2005002074A1
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WIPO (PCT)
Prior art keywords
signal
phase
compensation module
variation compensation
gain control
Prior art date
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PCT/US2004/014100
Other languages
French (fr)
Inventor
Alpaslan Demir
Leonid Kazakevich
Tanbir Haque
Original Assignee
Interdigital Technology Corporation
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Filing date
Publication date
Application filed by Interdigital Technology Corporation filed Critical Interdigital Technology Corporation
Priority to AU2004253071A priority Critical patent/AU2004253071B2/en
Priority to CA002528338A priority patent/CA2528338A1/en
Priority to MXPA05013199A priority patent/MXPA05013199A/en
Priority to JP2006514302A priority patent/JP2006527535A/en
Priority to EP04751468A priority patent/EP1632029A4/en
Priority to BRPI0411386-1A priority patent/BRPI0411386A/en
Publication of WO2005002074A1 publication Critical patent/WO2005002074A1/en
Priority to IL172031A priority patent/IL172031A0/en
Priority to NO20060092A priority patent/NO20060092L/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H04L27/3809—Amplitude regulation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/001—Digital control of analog signals
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3052—Automatic control in amplifiers having semiconductor devices in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/005—Control of transmission; Equalising
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/38—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end
    • H04L2027/0026—Correction of carrier offset
    • H04L2027/003—Correction of carrier offset at baseband only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0044—Control loops for carrier regulation
    • H04L2027/0046—Open loops
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/52—TPC using AGC [Automatic Gain Control] circuits or amplifiers

Definitions

  • the present invention generally relates to wireless communication systems. More particularly, the present invention relates to digital signal processing (DSP) techniques used to compensate for phase variations associated with automatic gain control (AGC) adjustments.
  • DSP digital signal processing
  • AGC automatic gain control
  • a receiver uses automatic gain control (AGC) to automatically adjust gain as a function of the amplitude of a radio frequency (RF) and/or intermediate frequency (IF) communication signal.
  • a real valued gain factor generated by the AGC is applied to the communication signal.
  • the amplitude of the communication signal is maintained within a predefined signal amplitude range and is then converted to a digital signal by an analog to digital converter (ADC), which also limits the signal amplitude range.
  • ADC analog to digital converter
  • the objective of the AGC is to maintain a constant power level at the input to the ADC.
  • AGC When the AGC is adjusted, a phase offset is introduced into the communication signal which degrades the performance of the phase-sensitive communication system.
  • a method and system is desired for canceling the phase offset of the communication signal caused by adjusting the AGC.
  • the present invention is incorporated into a communication system which includes an AGC circuit, a receiver, an analog to digital converter (ADC) and an insertion phase variation compensation module.
  • the AGC circuit receives and amplifies communication signals. The gain of the AGC circuit is continuously adjusted.
  • the AGC circuit outputs an amplified communication signal to the receiver which, in turn, outputs an analog complex signal to the ADC.
  • the ADC outputs a digital complex signal to the insertion phase variation compensation module which counteracts the effects of phase offsets introduced into the communication signal due to the continuous gain adjustments associated with the AGC circuit.
  • the analog and digital complex signals include in-phase (I) and quadrature (Q) signal components.
  • the gain of the AGC circuit is continuously adjusted in response to a gain control signal. Estimates of the phase offsets are provided to the insertion phase variation compensation module as a function of the gain control signal.
  • the insertion phase variation compensation module may receive the digital I and Q signal components from the ADC and output altered I and Q signal components having different phase characteristics than the digital I and Q signal components.
  • the communication system may further include a modem which receives the altered I and Q signal components.
  • the modem may include a processor which generates the gain control signal. The processor may calculate how much power is input to the ADC.
  • the communication system may further include a look up table (LUT) in communication with the processor and the insertion phase variation compensation module.
  • the LUT may receive the gain control signal from the processor and provide estimates of the phase offsets to the insertion phase variation compensation module as a function of the gain control signal.
  • the provided estimates may include a Sin function and a Cos function of a phase offset, x.
  • the insertion phase variation compensation module may have a real, Re, input associated with a digital I signal component and an imaginary, Im, input associated with a Q signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module may output an I signal component having a phase that is adjusted in accordance with the function (Cos(x) x Re) - (Sin(x) x Im) and a Q signal component having a phase that is adjusted in accordance with the function (Sin(x) x Re) + (Cos(x) x Im).
  • Figure 1 is a block diagram of a communication system including an insertion phase variation compensation module that cancels out phase offsets introduced into a communication signal by an AGC circuit in accordance with the present invention
  • Figure 2 is an exemplary configuration of the insertion phase variation compensation module of Figure 1;
  • Figure 3 is a flow chart of a process including steps implemented to continuously counteract the effects of phase offsets introduced into a communication signal by the AGC circuit of Figure 1.
  • the present invention provides a method and system that cancels out the phase difference introduced into an RF or IF communication signal, (i.e., data stream), by performing AGC adjustments.
  • a WTRU wireless transmit/receive unit
  • a WTRU includes but is not limited to a user equipment, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment.
  • the features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.
  • FIG. 1 is a block diagram of a communication system 100 operating in accordance with the present invention.
  • Communication system 100 includes an AGC circuit 105, a receiver 110, an analog to digital converter (ADC) 115, an insertion phase variation compensation module 120 and a modem 125.
  • AGC circuit 105 and the ADC 115 may be incorporated into receiver 110.
  • the AGC circuit 105 may include a single gain stage or multiple gain stages.
  • the insertion phase variation compensation module 120 may be incorporated into the modem 125.
  • the modem 125 includes a processor 130 which calculates how much power is input to the ADC 115.
  • the modem 125 receives complex I and Q signal components 135, 140, from the insertion phase variation compensation module 120, and, via processor 130, outputs a gain control signal 145 to the AGC circuit 105.
  • the gain control signal 145 includes a gain factor used by the AGC circuit 105 to set the amplitude of an RF and/or IF communication signal 150.
  • the gain control signal 145 is also output from the processor 130 to a look up table (LUT) 155 which uses the gain control signal 145 to provide the insertion phase variation compensation module 120 with an estimate of the phase offset that is introduced into the communication signal 150.
  • LUT look up table
  • a predefined polynomial or any other method may be used in lieu of the LUT 155 to provide the estimate of the phase offset.
  • phase offset i.e., phase rotation
  • an estimate of the phase offset (x) as a function of the gain provided by the AGC circuit 105 may be determined on a continuous basis by accessing the LUT 155, a predefined polynomial, or any other method that can map a full range of AGC values associated with the AGC circuit 105 to a phase offset estimate.
  • Figure 2 shows an exemplary configuration of the insertion phase variation compensation module 120 which rotates the phase characteristics of the I and Q signal components of a digital complex signal output from the ADC 115 based on the gain control signal 145, so as to counteract the effects of phase offsets introduced into a communication signal 150 by the AGC circuit 105.
  • the modem 125 is not affected by the phase offsets and the performance of the communication system 100 is not degraded. Different gain levels will introduce different gain offsets into the communication signal 150.
  • the insertion phase variation compensation module 120 includes multipliers 205, 210, 215, 220 and adders 225 and 230.
  • the insertion phase variation compensation module 120 receives a real (Re) I signal component 250 and an imaginary (jlm) Q signal component 260 from the ADC
  • Equation 1 Equation 1 below:
  • Equation 2 The outcome of the real output, Re , is described by Equation 2 below:
  • Equation 4 The output of the imaginary output, / m , is described by Equation 4 below:
  • the real signal component 250 is multiplied by a Cos(x) function 280 specified by the LUT 155 via the multiplier 215 and the imaginary signal component 260 is multiplied by a Sin (x) function 270 also specified by the LUT 155 via the multiplier 210, whereby the output of the multiplier 210 is subtracted from the output of the multiplier 215 by the adder 225.
  • the real signal component 250 is multiplied by a Sin(x) function 270 specified by the LUT 155 via the multiplier 205 and the imaginary signal component 260 is multiplied by a Cos(x) function 280 also specified by the LUT 155 via the multiplier 220, whereby the output of the multiplier 220 is added to the output of the multiplier 205 by the adder 230.
  • FIG. 3 is a flow chart of a process 300 including steps implemented to continuously counteract the effects of phase offsets introduced into a communication signal 150 received by the AGC circuit 105.
  • the gain control signal 145 is provided to the AGC circuit 105.
  • the AGC circuit 105 adjusts the gain of a communication signal 150 in response to the gain control signal 145, the adjustment causing a phase offset to be introduced into the communication signal 150.
  • an estimate of the phase offset is provided to the insertion phase variation compensation module 120 as a function of the gain control signal 145.
  • the insertion phase variation compensation module 120 adjusts the phase of the communication signal 150 based on the provided estimate.
  • the process 300 repeats on a continuous basis.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Circuits Of Receivers In General (AREA)
  • Control Of Amplification And Gain Control (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

A communication system (100) including an automatic control (AGC) circuit (105), a receiver (110), an analog to digital (ADC) converter (115) and an insertion phase variation compensation module (120). The AGC circuit receives and amplifies communication signals (150). The gain of the AGC circuit is adjusted. The AGC circuit outputsan amplified signal (145) to the receiver which, in turn, outputs an analog complex signal to the ADC (115). The ADC outputs a digital complex signal to the insertion phase variation compensation module (120) which counteracts the effects of phase offsets introduced into the communication signal due to the continuous gain adjustments associated with the AGC circuit.

Description

[0001] METHOD AND SYSTEM FOR CONTINUOUSLY COMPENSATING FOR PHASE VARIATIONS INTRODUCED INTO A COMMUNICATION SIGNAL BY AUTOMATIC GAIN CONTROL ADJUSTMENTS
[0002] FIELD OF THE INVENTION
[0003] The present invention generally relates to wireless communication systems. More particularly, the present invention relates to digital signal processing (DSP) techniques used to compensate for phase variations associated with automatic gain control (AGC) adjustments.
[0004] BACKGROUND
[0005] In a conventional phase-sensitive communication system, a receiver uses automatic gain control (AGC) to automatically adjust gain as a function of the amplitude of a radio frequency (RF) and/or intermediate frequency (IF) communication signal. A real valued gain factor generated by the AGC is applied to the communication signal. In the analog domain, the amplitude of the communication signal is maintained within a predefined signal amplitude range and is then converted to a digital signal by an analog to digital converter (ADC), which also limits the signal amplitude range. The objective of the AGC is to maintain a constant power level at the input to the ADC. [0006] When the AGC is adjusted, a phase offset is introduced into the communication signal which degrades the performance of the phase-sensitive communication system. A method and system is desired for canceling the phase offset of the communication signal caused by adjusting the AGC. [0007] SUMMARY
[0008] The present invention is incorporated into a communication system which includes an AGC circuit, a receiver, an analog to digital converter (ADC) and an insertion phase variation compensation module. The AGC circuit receives and amplifies communication signals. The gain of the AGC circuit is continuously adjusted. The AGC circuit outputs an amplified communication signal to the receiver which, in turn, outputs an analog complex signal to the ADC. The ADC outputs a digital complex signal to the insertion phase variation compensation module which counteracts the effects of phase offsets introduced into the communication signal due to the continuous gain adjustments associated with the AGC circuit. The analog and digital complex signals include in-phase (I) and quadrature (Q) signal components.
[0009] The gain of the AGC circuit is continuously adjusted in response to a gain control signal. Estimates of the phase offsets are provided to the insertion phase variation compensation module as a function of the gain control signal. [0010] The insertion phase variation compensation module may receive the digital I and Q signal components from the ADC and output altered I and Q signal components having different phase characteristics than the digital I and Q signal components. The communication system may further include a modem which receives the altered I and Q signal components. The modem may include a processor which generates the gain control signal. The processor may calculate how much power is input to the ADC.
[0011] The communication system may further include a look up table (LUT) in communication with the processor and the insertion phase variation compensation module. The LUT may receive the gain control signal from the processor and provide estimates of the phase offsets to the insertion phase variation compensation module as a function of the gain control signal. The provided estimates may include a Sin function and a Cos function of a phase offset, x. The insertion phase variation compensation module may have a real, Re, input associated with a digital I signal component and an imaginary, Im, input associated with a Q signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module may output an I signal component having a phase that is adjusted in accordance with the function (Cos(x) x Re) - (Sin(x) x Im) and a Q signal component having a phase that is adjusted in accordance with the function (Sin(x) x Re) + (Cos(x) x Im). [0012] BRIEF DESCRIPTION OF THE DRAWINGS
[0013] A more detailed understanding of the invention may be had from the following description of a preferred example, given by way of example and to be understood in conjunction with the accompanying drawing wherein:
[0014] Figure 1 is a block diagram of a communication system including an insertion phase variation compensation module that cancels out phase offsets introduced into a communication signal by an AGC circuit in accordance with the present invention;
[0015] Figure 2 is an exemplary configuration of the insertion phase variation compensation module of Figure 1; and
[0016] Figure 3 is a flow chart of a process including steps implemented to continuously counteract the effects of phase offsets introduced into a communication signal by the AGC circuit of Figure 1.
[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] The present invention provides a method and system that cancels out the phase difference introduced into an RF or IF communication signal, (i.e., data stream), by performing AGC adjustments.
[0019] Preferably, the method and system disclosed herein is incorporated into a wireless transmit/receive unit (WTRU). Hereafter, a WTRU includes but is not limited to a user equipment, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. The features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.
[0020] The present invention is applicable to communication systems using time division duplex (TDD), frequency division duplex (FDD), code division multiple access (CDMA), CDMA 2000, time division synchronous CDMA (TDSCDMA), orthogonal frequency division multiplexing (OFDM) or the like. [0021] Figure 1 is a block diagram of a communication system 100 operating in accordance with the present invention. Communication system 100 includes an AGC circuit 105, a receiver 110, an analog to digital converter (ADC) 115, an insertion phase variation compensation module 120 and a modem 125. The AGC circuit 105 and the ADC 115 may be incorporated into receiver 110. The AGC circuit 105 may include a single gain stage or multiple gain stages. Furthermore, the insertion phase variation compensation module 120 may be incorporated into the modem 125.
[0022] The modem 125 includes a processor 130 which calculates how much power is input to the ADC 115. The modem 125 receives complex I and Q signal components 135, 140, from the insertion phase variation compensation module 120, and, via processor 130, outputs a gain control signal 145 to the AGC circuit 105. The gain control signal 145 includes a gain factor used by the AGC circuit 105 to set the amplitude of an RF and/or IF communication signal 150. The gain control signal 145 is also output from the processor 130 to a look up table (LUT) 155 which uses the gain control signal 145 to provide the insertion phase variation compensation module 120 with an estimate of the phase offset that is introduced into the communication signal 150. Alternatively, a predefined polynomial or any other method may be used in lieu of the LUT 155 to provide the estimate of the phase offset.
[0023] Each time the gain level of the gain stage(s) of the AGC circuit 105 is changed, an associated phase offset, i.e., phase rotation, may be introduced into the communication signal 150. Thus, an estimate of the phase offset (x) as a function of the gain provided by the AGC circuit 105 may be determined on a continuous basis by accessing the LUT 155, a predefined polynomial, or any other method that can map a full range of AGC values associated with the AGC circuit 105 to a phase offset estimate.
[0024] Figure 2 shows an exemplary configuration of the insertion phase variation compensation module 120 which rotates the phase characteristics of the I and Q signal components of a digital complex signal output from the ADC 115 based on the gain control signal 145, so as to counteract the effects of phase offsets introduced into a communication signal 150 by the AGC circuit 105. Thus, the modem 125 is not affected by the phase offsets and the performance of the communication system 100 is not degraded. Different gain levels will introduce different gain offsets into the communication signal 150.
[0025] As shown in Figure 2, the insertion phase variation compensation module 120 includes multipliers 205, 210, 215, 220 and adders 225 and 230. The insertion phase variation compensation module 120 receives a real (Re) I signal component 250 and an imaginary (jlm) Q signal component 260 from the ADC
115 and rotates the phase of the signal components Re and jlm by x degrees (eiχ) as described by Equation 1 below:
(Re +jlm) x eiχ = (Re +jlm) x (Cos(x) + jSin(x)) Equation 1
[0026] The outcome of the real output, Re , is described by Equation 2 below:
Re = (Cos(x) x Re) + (j2 x Sin(x) x Im) = (Cos(x) x Re) - (Sin(x) x Im) Equation 2 Note that if x is close to zero, then Cos(x) = 1.0 and Sin(x) = x, as described by Equation 3 below:
R e = Re - Im x x Equation 3
[0027] The output of the imaginary output, / m , is described by Equation 4 below:
Im = (Sin(x) x Re) + (Cos(x) x Im) Equation 4
Note that if x is close to zero, then Cos(x) = 1.0 and Sin(x) = x, as described by Equation 5 below:
I m = Im + Re x x Equation 5
[0028] Thus, as depicted by Equation 2, the real signal component 250 is multiplied by a Cos(x) function 280 specified by the LUT 155 via the multiplier 215 and the imaginary signal component 260 is multiplied by a Sin (x) function 270 also specified by the LUT 155 via the multiplier 210, whereby the output of the multiplier 210 is subtracted from the output of the multiplier 215 by the adder 225. Furthermore, as depicted by Equation 4, the real signal component 250 is multiplied by a Sin(x) function 270 specified by the LUT 155 via the multiplier 205 and the imaginary signal component 260 is multiplied by a Cos(x) function 280 also specified by the LUT 155 via the multiplier 220, whereby the output of the multiplier 220 is added to the output of the multiplier 205 by the adder 230.
[0029] Figure 3 is a flow chart of a process 300 including steps implemented to continuously counteract the effects of phase offsets introduced into a communication signal 150 received by the AGC circuit 105. In step 305, the gain control signal 145 is provided to the AGC circuit 105. In step 310, the AGC circuit 105 adjusts the gain of a communication signal 150 in response to the gain control signal 145, the adjustment causing a phase offset to be introduced into the communication signal 150. In step 315, an estimate of the phase offset is provided to the insertion phase variation compensation module 120 as a function of the gain control signal 145. In step 320, the insertion phase variation compensation module 120 adjusts the phase of the communication signal 150 based on the provided estimate. The process 300 repeats on a continuous basis. [0030] While this invention has been particularly shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention described hereinabove.

Claims

CLAIMS What is claimed is: 1. A communication system comprising: (a) an automatic gain control (AGC) circuit which receives and adjusts the gain of a communication signal, the AGC being controlled by a gain control signal; and (b) an insertion phase variation compensation module which continuously counteracts the effects of phase offsets introduced into the communication signal by the AGC circuit, based on the gain control signal.
2. The communication system of claim 1 further comprising: (c) a receiver which receives the communication signal from the AGC circuit and outputs analog in-phase (I) and quadrature (Q) signal components; and (d) an analog to digital converter (ADC) which receives and converts the analog I and Q signal components to digital I and Q signal components.
3. The communication system of claim 2 wherein the insertion phase variation compensation module receives the digital I and Q signal components from the ADC and outputs altered I and Q signal components having different phase characteristics than the digital I and Q components, the communication system further comprising: (e) a modem which receives the altered I and Q signal components, the modem including a processor which generates the gain control signal.
4. The communication system of claim 3 wherein the processor calculates how much power is input to the ADC.
5. The communication system of claim 2 wherein the insertion phase variation compensation module receives the digital I and Q components from the ADC and alters the phase characteristics of the digital I and Q components as a function of the gain control signal.
6. The communication system of claim 1 further comprising: (c) a processor which generates the gain control signal; and (d) a look up table (LUT) in communication with the processor and the insertion phase variation compensation module, wherein the LUT receives the gain control signal from the processor and provides estimates of the phase offsets to the insertion phase variation compensation module as a function of the gain control signal.
7. The communication system of claim 6 wherein the provided estimates include a Sin function and a Cos function of a phase offset, x.
8. The communication system of claim 7 wherein the insertion phase variation compensation module has a real, Re, input associated with a digital in- phase (I) signal component and an imaginary, Im, input associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs an I signal component having a phase that is adjusted in accordance with the following function: (Cos(x) x Re) - (Sin(x) x Im).
9. The communication system of claim 7 wherein the insertion phase variation compensation module has a real input, Re, associated with a digital in- phase (I) signal component and an imaginary input, Im, associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs a Q signal component having a phase that is adjusted in accordance with the following function: (Sin(x) x Re) + (Cos(x) x Im).
10. A wireless transmit/receive unit (WTRU) comprising: (a) an automatic gain control (AGC) circuit which receives and adjusts the gain of a communication signal, the AGC being controlled by a gain control signal; and (b) an insertion phase variation compensation module which continuously counteracts the effects of phase offsets introduced into the communication signal by the AGC circuit, based on the gain control signal.
11. The WTRU of claim 10 further comprising: (c) a receiver which receives the communication signal from the AGC circuit and outputs analog in-phase (I) and quadrature (Q) signal components; and (d) an analog to digital converter (ADC) which receives and converts the analog I and Q signal components to digital I and Q signal components.
12. The WTRU of claim 11 wherein the insertion phase variation compensation module receives the digital I and Q signal components from the ADC and outputs altered I and Q signal components having different phase characteristics than the digital I and Q components, the WTRU further comprising: (e) a modem which receives the altered I and Q signal components, the modem including a processor which generates the gain control signal.
13. The WTRU of claim 12 wherein the processor calculates how much power is input to the ADC.
14. The WTRU of claim 11 wherein the insertion phase variation compensation module receives the digital I and Q components from the ADC and alters the phase characteristics of the digital I and Q components as a function of the gain control signal.
15. The WTRU of claim 10 further comprising: (c) a processor which generates the gain control signal; and (d) a look up table (LUT) in communication with the processor and the insertion phase variation compensation module, wherein the LUT receives the gain control signal from the processor and provides estimates of the phase offsets to the insertion phase variation compensation module as a function of the gain control signal.
16. The WTRU of claim 15 wherein the provided estimates include a Sin function and a Cos function of a phase offset, x.
17. The WTRU of claim 16 wherein the insertion phase variation compensation module has a real, Re, input associated with a digital in-phase (I) signal component and an imaginary, Im, input associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs an I signal component having a phase that is adjusted in accordance with the following function: (Cos(x) x Re) - (Sin(x) x Im).
18. The WTRU of claim 16 wherein the insertion phase variation compensation module has a real input, Re, associated with a digital in-phase (I) signal component and an imaginary input, Im, associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs a Q signal component having a phase that is adjusted in accordance with the following function: (Sin(x) x Re) + (Cos(x) x Im).
19. An integrated circuit (IC) comprising: (a) an automatic gain control (AGC) circuit which receives and adjusts the gain of a communication signal, the AGC being controlled by a gain control signal; and (b) an insertion phase variation compensation module which continuously counteracts the effects of phase offsets introduced into the communication signal by the AGC circuit, based on the gain control signal.
20. The IC of claim 19 further comprising: (c) a receiver which receives the communication signal from the AGC circuit and outputs analog in-phase (I) and quadrature (Q) signal components; and (d) an analog to digital converter (ADC) which receives and converts the analog I and Q signal components to digital I and Q signal components.
21. The IC of claim 20 wherein the insertion phase variation compensation module receives the digital I and Q signal components from the ADC and outputs altered I and Q signal components having different phase characteristics than the digital I and Q components, the WTRU further comprising: (e) a. modem which receives the altered I and Q signal components, the modem including a processor which generates the gain control signal.
22. The IC of claim 21 wherein the processor calculates how much power is input to the ADC.
23. The IC of claim 20 wherein the insertion phase variation compensation module receives the digital I and Q components from the ADC and alters the phase characteristics of the digital I and Q components as a function of the gain control signal.
24. The IC of claim 19 further comprising: (c) a processor which generates the gain control signal; and (d) a look up table (LUT) in communication with the processor and the insertion phase variation compensation module, wherein the LUT receives the gain control signal from the processor and provides estimates of the phase offsets to the insertion phase variation compensation module as a function of the gain control signal.
25. The IC of claim 24 wherein the provided estimates include a Sin function and a Cos function of a phase offset, x.
26. The IC of claim 25 wherein the insertion phase variation compensation module has a real, Re, input associated with a digital in-phase (I) signal component and an imaginary, Im, input associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs an I signal component having a phase that is adjusted in accordance with the following function: (Cos(x) x Re) - (Sin(x) x Im).
27. The IC of claim 25 wherein the insertion phase variation compensation module has a real input, Re, associated with a digital in-phase (I) signal component and an imaginary input, Im, associated with a quadrature (Q) signal component and, based on the estimates provided by the LUT, the insertion phase variation compensation module outputs a Q signal component having a phase that is adjusted in accordance with the following function: (Sin(x) x Re) + (Cos(x) x Im).
28. In a communication system including an automatic gain control (AGC) circuit and an insertion phase variation compensation module, a method of continuously counteracting the effects of phase offsets introduced into a communication signal by the AGC circuit, the method comprising: (a) providing a gain control signal to the AGC circuit; (b) the AGC circuit receiving and adjusting the gain of a communication signal in response to the gain control signal, the adjustment causing a phase offset to be introduced into the communication signal; (c) providing an estimate of the phase offset to the insertion phase variation compensation module as a function of the gain control signal; (d) the insertion phase variation compensation module adjusting the phase of the communication signal based on the provided estimate; and (e) repeating steps (a) - (d).
29. The method of claim 28 wherein the provided estimate includes a Sin function and a Cos function of a phase offset, x.
30. The method of claim 29 wherein the insertion phase variation compensation module has a real, Re, input associated with a digital in-phase (I) signal component and an imaginary, Im, input associated with a quadrature (Q) signal component and, based on the estimate provided by the LUT, the insertion phase variation compensation module outputs an I signal component having a phase that is adjusted in accordance with the following function: (Cos(x) x Re) - (Sin(x) x Im).
31. The method of claim 29 wherein the insertion phase variation compensation module has a real input, Re, associated with a digital in-phase (I) signal component and an imaginary input, Im, associated with a quadrature (Q) signal component and, based on the estimate provided by the LUT, the insertion phase variation compensation module outputs a Q signal component having a phase that is adjusted in accordance with the following function: (Sin(x) x Re) + (Cos(x) x Im).
PCT/US2004/014100 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments WO2005002074A1 (en)

Priority Applications (8)

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AU2004253071A AU2004253071B2 (en) 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments
CA002528338A CA2528338A1 (en) 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments
MXPA05013199A MXPA05013199A (en) 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments.
JP2006514302A JP2006527535A (en) 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced in a communication signal by automatic gain control adjustment
EP04751468A EP1632029A4 (en) 2003-06-06 2004-05-06 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments
BRPI0411386-1A BRPI0411386A (en) 2003-06-06 2004-05-06 method and system of continuous compensation of phase variations introduced in communication signal by automatic gain control settings
IL172031A IL172031A0 (en) 2003-06-06 2005-11-17 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments
NO20060092A NO20060092L (en) 2003-06-06 2006-01-06 Phase Variation Compensation Method and System Introduced in a Communication Signal of AGC Adjustments

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US47647103P 2003-06-06 2003-06-06
US60/476,471 2003-06-06
US10/736,432 US20060183451A1 (en) 2003-06-06 2003-12-15 Method and system for continuously compensating for phase variations introduced into a communication signal by automatic gain control adjustments
US10/736,432 2003-12-15

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TW200822542A (en) 2008-05-16
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IL172031A0 (en) 2009-02-11
AU2004253071B2 (en) 2007-05-24
NO20060092L (en) 2006-03-06
BRPI0411386A (en) 2006-07-18
MXPA05013199A (en) 2006-03-09
JP2006527535A (en) 2006-11-30
TW200537797A (en) 2005-11-16
TW200428766A (en) 2004-12-16
EP1632029A1 (en) 2006-03-08
TWI278180B (en) 2007-04-01
EP1632029A4 (en) 2008-07-02
KR20060024790A (en) 2006-03-17
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US20060183451A1 (en) 2006-08-17
CA2528338A1 (en) 2005-01-06

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