GB2281461A - Control of output power in radio transmitters using look-up table - Google Patents
Control of output power in radio transmitters using look-up table Download PDFInfo
- Publication number
- GB2281461A GB2281461A GB9317900A GB9317900A GB2281461A GB 2281461 A GB2281461 A GB 2281461A GB 9317900 A GB9317900 A GB 9317900A GB 9317900 A GB9317900 A GB 9317900A GB 2281461 A GB2281461 A GB 2281461A
- Authority
- GB
- United Kingdom
- Prior art keywords
- output power
- frequency
- power level
- signal
- transmitter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000007704 transition Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 230000001413 cellular effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
Classifications
-
- 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
- H04W52/30—TPC using constraints in the total amount of available transmission power
- H04W52/36—TPC using constraints in the total amount of available transmission power with a discrete range or set of values, e.g. step size, ramping or offsets
- H04W52/367—Power values between minimum and maximum limits, e.g. dynamic range
-
- 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
- H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers
- H03G3/3042—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers in modulators, frequency-changers, transmitters or power amplifiers
- H03G3/3047—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers in modulators, frequency-changers, transmitters or power amplifiers for intermittent signals, e.g. burst signals
-
- 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
- H04W52/30—TPC using constraints in the total amount of available transmission power
- H04W52/36—TPC using constraints in the total amount of available transmission power with a discrete range or set of values, e.g. step size, ramping or offsets
- H04W52/362—Aspects of the step size
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmitters (AREA)
Abstract
Apparatus for controlling the output power level of a transmitted signal comprises a read only memory (ROM) 20 having stored therein information concerning desired output power levels. Access to the ROM 20 is governed by a microcontroller 22 to which are fed three signals, a first signal 24 representative of a required power level, a signal 26 representative of frequency of a frequency synthesiser and a signal 28 representative of temperature. The ROM 20 supplies a desired power output level signal, compensated for frequency and temperature variations, to an attenuator 12 which modifies the input signal fed to an amplifier 16 producing the transmitted signal. <IMAGE>
Description
Control of Output Power in Radio Transmitters
This invention relates to controlling output power in radio transmitters.
The conventional approach to controlling the output power in a radio transmitter is to use a closed loop system, as illustrated in Figure 1 of the accompanying drawings. A sample of the detected radio frequency output is compared with a reference voltage, which is an analogue signal representative of a desired output power level. The resulting difference signal is used to control an attenuator at the input of an amplifier, thus completing the control loop. This approach has particular disadvantages for cellular radio conforming to the GSM (Groupe Systeme Mobile) standard, namely:
(a) a linearised detector and a linearised attenuator
are required to accommodate the large dynamic range
(b) the fast power ramping required between timeslots
in GSM makes the control loop difficult to design.
Extra poles within the loop lead to overshoot.
According to the invention apparatus for controlling the output power of a radio transmitter comprises memory means having stored therein information concerning desired output power levels and adjusting means for adjusting the output power level in accordance with the information derived from the memory means.
Preferably the apparatus includes means for varying the output power to compensate for variations in temperature and for variations in frequency of a frequency synthesiser of the radio transmitter.
In a preferred embodiment the memory means comprise a read only memory controlled by a microcontroller having three inputs, namely a first input representative of a desired power level, a second input representative of the frequency and a third input representative of temperature, the microcontroller determining the address in the ROM from which the desired power level, compensated for frequency and temperature, is retrieved in accordance with the combination of the three inputs, the compensated power level signal being applied to the adjusting means.
The means for adjusting the output power level is preferably an attenuator controlling the input to an amplifier which provides the transmitter output signal.
Apparatus according to the invention may be incorporated in the transmitter of a base station and/or the transmitter of a mobile handset in a radio telephone system.
Hence, the invention overcomes the problems of the prior art by employing open loop control. This removes the need for a detector and means that the attenuator can be nonlinear.
Apparatus according to the invention will now be described by way of example with reference to Figures 2 and 3 of the accompanying drawings, in which:
Figure 2 is a block circuit diagram of the apparatus, and
Figure 3 is a timing diagram indicating power level changes at the transition between time slots.
Referring to Figure 2, the input power is supplied to the input 10 of an attenuator 12 which is controlled by a signal on a lead 14 and the output of which is supplied to an amplifier 16 which in turn provides the transmitter output power at 18. The control signal on lead 14 is derived from an open loop control arrangement.
A read only memory (ROM) 20 contains the power ramp information required to give the correct transition between the power levels of two successive time slots. At different addresses in the ROM are stored different power levels. The appropriate address, and therefore the appropriate required power level, is selected by a microcontroller 22 which selects a ROM address in dependence upon a blend of three input signals, namely a first digital signal 24 representing a power select level, a second digital signal 26 representing the frequency from the frequency synthesiser and a third digital signal 28 representative of the temperature of the amplifier, or possibly ambient temperature. The signal 28 is derived from a thermal probe 30 placed near to the amplifier 16, the signal from which is converted into digital form in a converter 32.The second and third signals 26, 28 therefore provide compensation for frequency variations and thermal changes, respectively.
The radio transmitter of Figure 2 is intended to conform to the GSM standard and to operate in time division multiple access (TDMA) employing eight time slots in each frame of transmitted data. Figure 3 shows how the requested power level signal 24 may vary at the transition between two time slots 34, 36 in a typical frame of transmitted data. A guard band 38 is provided between the time slots 34, 36 and the requested power level signal, which is digital, is shown stepping down from a higher level in the earlier time slot 34 to a lower level in the later time slot 36. When such a change in the requested power level occurs, a new output power level is selected from the stored values in the ROM, with compensation for frequency and temperature variations. This new output power level is converted into analogue form in a converter 40, filtered at 42 and fed on the lead 14 to the attenuator 12 as the control signal determining the output power of the transmitted signal for that time slot.
Claims (8)
1. Apparatus for controlling the output power of a radio transmitter, the apparatus comprising memory means having stored therein information concerning desired output power levels and adjusting means for adjusting the output power level in accordance with the information derived from the memory means.
2. Apparatus according to claim 1 and including means for varying the output power to compensate for variations in temperature and for variations in frequency of a frequency synthesiser of the radio transmitter.
3. Apparatus according to claim 2, wherein the memory means comprise a read only memory controlled by a microcontroller having three inputs, namely a first input representative of a desired power level, a second input representative of the frequency of the frequency synthesiser and a third input representative of temperature, the microcontroller determining the address in the ROM from which the desired power level, compensated for frequency and temperature, is retrieved in accordance with the combination of the three inputs, the compensated power level signal being applied to the adjusting means.
4. Apparatus according to any of the preceding claims, wherein the adjusting means is an attenuator which controls the input to an amplifier which provides the transmitter output signal.
5. Apparatus according to any of the preceding claims and forming the transmitter of a base station in a radio telephone system.
6. Apparatus according to any of claims 1 to 4 and forming the transmitter of a mobile handset in a radio telephone system.
7. Apparatus according to any of the preceding claims, wherein the radio transmitter uses time division multiple access (TDMA) and wherein a desired power level is read out of the memory means for each time slot.
8. Apparatus for controlling the output power of a radio transmitter, the apparatus being constructed and arranged substantially as herein particularly described with reference to Figures 2 and 3 of the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9317900A GB2281461A (en) | 1993-08-27 | 1993-08-27 | Control of output power in radio transmitters using look-up table |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9317900A GB2281461A (en) | 1993-08-27 | 1993-08-27 | Control of output power in radio transmitters using look-up table |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9317900D0 GB9317900D0 (en) | 1993-10-13 |
GB2281461A true GB2281461A (en) | 1995-03-01 |
Family
ID=10741176
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9317900A Withdrawn GB2281461A (en) | 1993-08-27 | 1993-08-27 | Control of output power in radio transmitters using look-up table |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2281461A (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2321806A (en) * | 1997-01-31 | 1998-08-05 | Samsung Electronics Co Ltd | Correction for frequency and temperature in output power control in rf transmitter |
WO1998018212A3 (en) * | 1996-10-22 | 1998-08-13 | Qualcomm Inc | Method and apparatus for performing a fast downward move in a cellular telephone forward link power control system |
EP0866550A2 (en) * | 1997-03-22 | 1998-09-23 | Lucent Technologies Network Systems GmbH | Pulse forming device of high frequency signals |
WO1999063660A1 (en) * | 1998-05-29 | 1999-12-09 | Telefonaktiebolaget Lm Ericsson (Publ) | Pre-recorded sigma delta values for power amplifier control |
EP1094618A1 (en) * | 1999-10-23 | 2001-04-25 | Siemens Aktiengesellschaft | Method of operating a mobile telephone system |
EP1120902A2 (en) * | 2000-01-18 | 2001-08-01 | Kokusai Electric Co., Ltd. | Transmitter and mobile station |
EP1160578A1 (en) * | 2000-05-31 | 2001-12-05 | Lucent Technologies Inc. | Method for standardizing a power detector |
EP1557956A1 (en) * | 2004-01-21 | 2005-07-27 | Nec Corporation | Transmission power control device and method thereof, computer program for transmission power control device, and radio transmitter |
WO2006013497A1 (en) * | 2004-07-28 | 2006-02-09 | Koninklijke Philips Electronics N.V. | Determining the current value of a transmission power of a radio telecommunication device |
EP1665462A2 (en) * | 2003-09-22 | 2006-06-07 | Motorola, Inc., A Corporation of the State of Delaware; | Amplifier power control in frequency hopping applications and methods |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0369135A2 (en) * | 1988-11-17 | 1990-05-23 | Motorola, Inc. | Power amplifier for a radio frequency signal |
EP0394063A2 (en) * | 1989-04-20 | 1990-10-24 | Nec Corporation | Radio communication apparatus having a simple structure |
EP0414352A2 (en) * | 1989-06-26 | 1991-02-27 | ORBITEL MOBILE COMMUNICATIONS LIMITED (Reg. no. 2515004) | Radio transmitter with output power control |
EP0420505A2 (en) * | 1989-09-25 | 1991-04-03 | Nokia Mobile Phones Ltd. | Method of tuning and compensating power levels in a radio telephone |
US5091919A (en) * | 1989-02-08 | 1992-02-25 | Nokia-Mobira Oy | Transmitter arrangement for digitally modulated signals |
US5101173A (en) * | 1990-11-28 | 1992-03-31 | The United States Of America As Represented By The Secretary Of The Air Force | Stored program controlled module amplifier bias and amplitude/phase compensation apparatus |
US5123031A (en) * | 1989-02-08 | 1992-06-16 | Nokia-Mobira Oy | Control voltage generator in a transmitter arrangement for digitally modulated signals |
EP0523718A2 (en) * | 1991-07-19 | 1993-01-20 | Nec Corporation | Output level control circuit for use in RF transmitter |
WO1993002505A1 (en) * | 1991-07-22 | 1993-02-04 | Motorola, Inc. | Power control circuitry for a tdma radio frequency transmitter |
-
1993
- 1993-08-27 GB GB9317900A patent/GB2281461A/en not_active Withdrawn
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0369135A2 (en) * | 1988-11-17 | 1990-05-23 | Motorola, Inc. | Power amplifier for a radio frequency signal |
US5091919A (en) * | 1989-02-08 | 1992-02-25 | Nokia-Mobira Oy | Transmitter arrangement for digitally modulated signals |
US5123031A (en) * | 1989-02-08 | 1992-06-16 | Nokia-Mobira Oy | Control voltage generator in a transmitter arrangement for digitally modulated signals |
EP0394063A2 (en) * | 1989-04-20 | 1990-10-24 | Nec Corporation | Radio communication apparatus having a simple structure |
EP0414352A2 (en) * | 1989-06-26 | 1991-02-27 | ORBITEL MOBILE COMMUNICATIONS LIMITED (Reg. no. 2515004) | Radio transmitter with output power control |
EP0420505A2 (en) * | 1989-09-25 | 1991-04-03 | Nokia Mobile Phones Ltd. | Method of tuning and compensating power levels in a radio telephone |
US5101173A (en) * | 1990-11-28 | 1992-03-31 | The United States Of America As Represented By The Secretary Of The Air Force | Stored program controlled module amplifier bias and amplitude/phase compensation apparatus |
EP0523718A2 (en) * | 1991-07-19 | 1993-01-20 | Nec Corporation | Output level control circuit for use in RF transmitter |
WO1993002505A1 (en) * | 1991-07-22 | 1993-02-04 | Motorola, Inc. | Power control circuitry for a tdma radio frequency transmitter |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1998018212A3 (en) * | 1996-10-22 | 1998-08-13 | Qualcomm Inc | Method and apparatus for performing a fast downward move in a cellular telephone forward link power control system |
US5960361A (en) * | 1996-10-22 | 1999-09-28 | Qualcomm Incorporated | Method and apparatus for performing a fast downward move in a cellular telephone forward link power control system |
GB2321806A (en) * | 1997-01-31 | 1998-08-05 | Samsung Electronics Co Ltd | Correction for frequency and temperature in output power control in rf transmitter |
FR2759219A1 (en) * | 1997-01-31 | 1998-08-07 | Samsung Electronics Co Ltd | METHOD FOR CONTROLLING THE POWER OF A RADIO SIGNAL BASED ON FREQUENCY AND TEMPERATURE VARIATIONS IN A PERSON SEARCH TRANSMITTER |
GB2321806B (en) * | 1997-01-31 | 1999-08-25 | Samsung Electronics Co Ltd | Power control system and method |
US6115587A (en) * | 1997-01-31 | 2000-09-05 | Samsung Electronics Co., Ltd. | Radio signal power control method according to variation of frequency and temperature in paging transmitter |
EP0866550A2 (en) * | 1997-03-22 | 1998-09-23 | Lucent Technologies Network Systems GmbH | Pulse forming device of high frequency signals |
EP0866550A3 (en) * | 1997-03-22 | 1998-09-30 | Lucent Technologies Network Systems GmbH | Pulse forming device of high frequency signals |
WO1999063660A1 (en) * | 1998-05-29 | 1999-12-09 | Telefonaktiebolaget Lm Ericsson (Publ) | Pre-recorded sigma delta values for power amplifier control |
US6097251A (en) * | 1998-05-29 | 2000-08-01 | Telefonaktiebolaget Lm Ericsson | Pre-recorded sigma delta values for power amplifier control |
EP1094618A1 (en) * | 1999-10-23 | 2001-04-25 | Siemens Aktiengesellschaft | Method of operating a mobile telephone system |
EP1120902A2 (en) * | 2000-01-18 | 2001-08-01 | Kokusai Electric Co., Ltd. | Transmitter and mobile station |
EP1120902A3 (en) * | 2000-01-18 | 2005-04-27 | Kokusai Electric Co., Ltd. | Transmitter and mobile station |
EP1160578A1 (en) * | 2000-05-31 | 2001-12-05 | Lucent Technologies Inc. | Method for standardizing a power detector |
EP1665462A2 (en) * | 2003-09-22 | 2006-06-07 | Motorola, Inc., A Corporation of the State of Delaware; | Amplifier power control in frequency hopping applications and methods |
EP1665462A4 (en) * | 2003-09-22 | 2009-12-02 | Motorola Inc | Amplifier power control in frequency hopping applications and methods |
EP1557956A1 (en) * | 2004-01-21 | 2005-07-27 | Nec Corporation | Transmission power control device and method thereof, computer program for transmission power control device, and radio transmitter |
CN100356701C (en) * | 2004-01-21 | 2007-12-19 | 日本电气株式会社 | Transmission power control device and method thereof, computer program for transmission power control device, and radio transmitter |
US7363012B2 (en) | 2004-01-21 | 2008-04-22 | Nec Corporation | Transmission power control device and method thereof, computer program for transmission power control device, and radio transmitter |
WO2006013497A1 (en) * | 2004-07-28 | 2006-02-09 | Koninklijke Philips Electronics N.V. | Determining the current value of a transmission power of a radio telecommunication device |
Also Published As
Publication number | Publication date |
---|---|
GB9317900D0 (en) | 1993-10-13 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |