WO2001005057A1 - Commande de puissance d'emission pour stations de base equipees mcpa - Google Patents

Commande de puissance d'emission pour stations de base equipees mcpa Download PDF

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Publication number
WO2001005057A1
WO2001005057A1 PCT/SE2000/001386 SE0001386W WO0105057A1 WO 2001005057 A1 WO2001005057 A1 WO 2001005057A1 SE 0001386 W SE0001386 W SE 0001386W WO 0105057 A1 WO0105057 A1 WO 0105057A1
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WO
WIPO (PCT)
Prior art keywords
power
mobile terminals
output signal
modified
requirement
Prior art date
Application number
PCT/SE2000/001386
Other languages
English (en)
Inventor
Bo Hedberg
Magnus Frodigh
Christer Johansson
Patrik Eriksson
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from US09/349,717 external-priority patent/US6570929B1/en
Priority claimed from US09/360,141 external-priority patent/US6694148B1/en
Application filed by Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Priority to EP00946677A priority Critical patent/EP1224745A1/fr
Priority to AU60398/00A priority patent/AU6039800A/en
Publication of WO2001005057A1 publication Critical patent/WO2001005057A1/fr

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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
    • H04W52/34—TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
    • H04W52/343—TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading taking into account loading or congestion level
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2614—Peak power aspects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2626—Arrangements specific to the transmitter only
    • H04L27/2627—Modulators
    • H04L27/2637—Modulators with direct modulation of individual subcarriers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/02—Channels characterised by the type of signal
    • H04L5/06—Channels characterised by the type of signal the signals being represented by different frequencies

Definitions

  • the present invention relates generally to cellular communication systems. More precisely, the present invention relates to a transmit power supervision method for a base station equipped with a multi-carrier power amplifier (MCPA).
  • MCPA multi-carrier power amplifier
  • a base station In conventional cellular systems, a base station is allocated a predetermined number of frequency channels for communication with mobile stations. In the base station a separate transmitter is employed for each frequency channel.
  • the use of separate transmitters for each frequency channel results in a duplication of parts and an increase in cost due to the additional hardware required. Thereafter, it was realized that the hardware cost per channel could be reduced by using multicarrier transmitters in place of the plurality of single carrier transmitters to transmit a plurality of frequency channels. Since multicarrier transmitters transmit over a broad range of frequencies, they are also sometimes referred to in the art as wideband transmitters. However, for ease of discussion, the transmitters will be referred to herein as multicarrier transmitters.
  • FIG. 1 illustrates a conventional multicarrier transmitter 100 which may be used to transmit multiple frequency channels from a base station in a radiocommunication system.
  • the conventional multicarrier transmitter 100 operates as follows.
  • a number N of baseband frequency data signals BB ] ....BB N are modulated by modulators Mod, Mod N , respectively, where the bits associated with each data signal are symbol encoded for transmission, i.e., the modulator generates the corresponding baseband waveform.
  • Each of the modulated data signals is forwarded to a corresponding digital power control module DPC, DPC N , where each DPC adjusts the signal power level of the corresponding modulated data signal based on the commands provided by the Radio Control Unit 150.
  • each modulated data signal is adjusted such that the absolute power level of each carrier P k out at the transmitter is equal to the amount of power required for the carrier to reach a particular mobile station which is to receive the carrier, where k varies from 1 to N and identifies the corresponding baseband frequency data signals BB ,...BB N .
  • the modulated data signals are then forwarded from the digital power control modules DPC, DPC N to multipliers Mult,....Mult N , respectively, where each modulated data signal is upconverted to a corresponding carrier frequency.
  • the upconverted signals are then summed by adder 110.
  • the compound signal produced by adder 110 is then forwarded to the digital-to-analog converter (DAC) 120.
  • DAC digital-to-analog converter
  • the resulting compound analog signal is then passed from DAC 120 through an analog transmitter chain which includes analog amplifier 160, upconverter (not shown), and filters (not shown).
  • Analog amplifier 160 then amplifies the compound signal by a fixed gain G ana .
  • G ana has been described as the gain of analog amplifier 160, however, one skilled in the art will recognize that G ana represents the total gain of the analog section of the transmitter, including losses due to filters and upconverters.
  • Multicarrier transmitters are designed to handle a maximum number of simultaneous carriers N .
  • P the instantaneous in-phase power sum
  • N the total number of carrier frequencies used by the base station. Normally, P is equal to the peak power within the specific time slot.
  • the instantaneous in-phase power sum of a single time slot for a system having, for example, a constant envelope is given by:
  • the DAC will clip the analog signal. Clipping, i.e., preventing the analog signal from exceeding the amplitude corresponding to the full scale range of the DAC will have an adverse effect on the quality of the transmitted signal.
  • a system might tolerate a power level which exceeds the DAC's full scale range by a small amount for short periods of time without suffering a decrease in system performance.
  • the abovementioned "clipping" of the analog signal can be avoided by setting the full scale range of the DAC to 20*log(N) dB above the maximum allowed peak power level of any individual carrier 1... N , since the full scale range set 20*log( ⁇ ) dB above the maximum power level of any individual carrier represents the greatest power level attainable by the sum of the N carriers.
  • TDM A is a communication technique whereby different signals are assigned to different time slots on the same frequencies.
  • FIG. 2 illustrates an exemplary time chart which may be associated with a base station.
  • seven frequencies (1-7) in use by an exemplary base station are illustrated over eight time slots.
  • the numbers in the time chart indicate the required output power, in watts, for a mobile unit which is operating at a particular frequency and assigned to a particular time slot. For example, at frequency 1 and time slot 1, the mobile unit requires 4 watts (W). P for each time slot is depicted below the time chart.
  • the serving MCPA must be designed for at least a maximum output power of 392W. That is, the MCPA must be designed to handle the worst-case scenario of each of the mobile units receiving at their maximum allocated power, 8W. As seen in FIG. 2, the in-phase power sum per time slot, P , will usually be lower than the maximum output power of 392W. This difference illustrates how the MPCA will not be used efficiently, since it must be designed to handle a worst-case scenario of all users being allocated the maximum output power for a given time slot.
  • Several techniques have been developed for extending the maximum capacity for which MCPAs have been dimensioned.
  • Load sharing is one such technique.
  • Conventional load sharing is basically a type of load balancing where a user is transferred from one cell which has reached its maximum capacity to another cell which can accommodate the user. This technique avoids overload situations.
  • the following patents illustrate conventional load sharing techniques.
  • a method of balancing the load among cells which are operating at maximum capacity is described in U.S. Patent No. 4,670,899, by Brody et al., and entitled “Load Balancing for Cellular Radio Telephone System. "
  • the loading of various cells is dynamically redistributed by selectively transferring ongoing calls to adjacent cells in accordance with traffic levels in order to reserve channels for handoffs and for new calls.
  • a channel occupancy level for a cell is periodically determined by comparing the number of channels utilized to the number of channels available within the cell. Calls are handed off before all the channels are utilized, thereby allowing at least one or more channels to be reserved for new or incoming calls.
  • Brody et al. if there is a mobile unit on the periphery of the cell which is also within the range of a neighboring cell, the mobile unit will be transferred to the neighboring cell in order to make room for a new call or an ongoing call associated with a mobile unit which will be handed off to the cell. While Brody et al. provides traffic-based control for call handoffs from one cell to an adjacent cell, handoffs due to load balancing are handled differently from handoffs due to mobile units leaving the cell. This creates a very complex system.
  • a reallocation or load sharing algorithm is invoked.
  • the reallocation algorithm searches for time slots to which a reallocation could be performed within the same base sation or number of transceivers served by the MCPA. If no time slots can handle users from the time slot in which the MCPA limit is exceeded, then a load sharing algorithm is activated and one starts to look for transmission resources in transceivers served by other MCPAs.
  • the present invention distinguishes over the above techniques by providing a more efficient allocation of average output power for a MCPA, the average output power being a weighted average of the actual power over multiple time slots.
  • Periodically, using the more efficient allocation system and method of the present invention there will be short periods where the desired output power will exceed the maximum tolerable power of the MCPA, P . These short periods in which the desired output power will exceed P MCP . are handled by an exemplary embodiment of the present invention which produces a reduced margin between the average total power over several time slots and P . This reduced margin allows the MCPA of the present invention to serve a larger number of users per time slot than conventional MCPAs.
  • the MCPA of the present invention can serve the same number of users as a conventional MCPA, but with higher demands on output power for each user and/or more efficient use of the MCPA 's resources.
  • a method for power control in a radio communication system includes determining a power requirement for an output signal; comparing the power requirement with a threshold power value; and modifying the output signal when the power requirement is greater than the threshold power value such that the modified output signal has a power requirement which is less than or equal to the threshold power value.
  • a method for power control in a radio communication system includes allocating a respective power for at least one of a plurality of mobile terminals such that an instantaneous power of an output signal for said plurality of mobile terminals will exceed a threshold power value of a power amplifier; determining a power requirement for the output signal; comparing the power requirement for the output signal with the threshold power value; and modifying the output signal when the power requirement is greater than the threshold power value such that the modified output signal has a modified power requirement which is less than or equal to the threshold power value.
  • a power control system for a radio communication system includes a power supervision unit which determines a power requirement for a portion of an output signal and compares the power requirement with a threshold power value; and a signal control unit which modifies the output signal when the power requirement is greater than the threshold power value such that the modified output signal has a modified power requirement which is less than or equal to the threshold power value.
  • a power control system includes means for allocating a respective power level for at least one of a plurality of mobile terminals such that an instantaneous power of an output signal for the plurality of mobile terminals will exceed a threshold power value of a power amplifier; means for determining a power requirement for the output signal; means for comparing the power requirement of the output signal with the threshold power value; and means for modifying the output signal when the power requirement is greater than the threshold power value such that the modified output signal has a modified power requirement which is less than or equal to the threshold power value.
  • a power control system for a radio communication system includes a power supervision unit which determines a power requirement for an output signal and compares the power requirement with a threshold power value.
  • a signal control unit variably modifies the output signal in a digital domain and in an analog domain and a power suppression unit coupled to the signal control unit modifies the power requirement when the power requirement is greater than the threshold power value such that the modified output signal has a modified power requirement which is less than or equal to the threshold power value.
  • a power control system for a radio communication system includes a digital power control module; a digital-to-analog converter; an analog power control module; a radio control unit for adjusting a gain of the digital power control module and for adjusting a gain of the analog power control module; and a power suppression unit coupled to the radio control unit for providing power control commands to the digital power control module.
  • a method for power control in a radio communication system is provided.
  • the method includes determining a power requirement for an output signal; comparing the power requirement with a threshold power value; variably modifying the output signal in a digital domain and in an analog domain; and modifying the power requirement when the power requirement is greater than the threshold power value such that the output signal has a modified power requirement which is less than or equal to the threshold power value.
  • a method of power control in a radio communication system includes modulating a plurality of baseband data streams; adjusting a power level of each of the plurality of modulated baseband data streams; upconverting, to a respective carrier frequency, each of the plurality of power modulated baseband data streams to form a plurality of individual carriers; combining the plurality of individual carriers into a single data stream with a power level requirement which is a function of the power levels associated with the plurality of individual carriers; modifying the power level requirement of the single data stream; converting the single data stream into an analog waveform; and variably adjusting the power level of the analog waveform.
  • the power control method of the present invention allows for a lower P , and, therefore, a lower cost MCPA to be employed by a base station.
  • the present invention does not need to sacrifice quality in order to reduce costs since it is able to maintain sufficient average power.
  • FIG. 1 illustrates a conventional base station employing a MCPA
  • FIG. 2 illustrates an exemplary time chart which may be associated with a base station
  • FIG. 3 illustrates an exemplary cellular mobile radio system
  • FIG. 4 illustrates an exemplary probability model utilized by the present invention
  • FIGS. 5A-5B illustrate the power control system according to exemplary embodiments of the present invention.
  • FIGS. 6A-6F illustrate power control methods according to exemplary embodiments of the present invention.
  • FIG. 3 illustrates an exemplary cellular mobile radio system.
  • the cellular mobile radio system is illustrated as comprising ten cells.
  • a typical cellular mobile radio system commonly includes more than ten cells; however, for the sake of brevity, the present invention is explained using the simplified representation illustrated in FIG. 3.
  • Each cell C1-C10 has a corresponding base station B1-B10.
  • FIG. 3 illustrates the base stations as situated in the vicinity of the cell center and having omni-directional antennas.
  • the cells C1-C10 are, therefore, schematically represented as hexagons.
  • the base stations of adjacent cells may, however, be co- located in the vicinity of cell borders and have directional antennas as is well known to those skilled in the art.
  • the base stations are equipped with MCPAs and operate using time division multiple access (TDM A) techniques.
  • TDM A time division multiple access
  • a single MCPA is shared by multiple co-located base stations.
  • FIG. 3 also illustrates nine mobile stations M1-M9, moveable within a cell and among a plurality of cells.
  • the reduced number of mobile stations is sufficient.
  • FIG. 3 Also illustrated in FIG. 3 is an exemplary number of base station controllers BSC1-BSC3 and a mobile switching center MSC.
  • the base station controllers BSC1-BSC3 control the operation of the base stations.
  • the mobile switching center MSC is connected to each of the base station controllers BSC1-BSC3 and to a fixed public switching telephone network or similar fixed network (not shown). While only one mobile switching center is illustrated in FIG. 3, one skilled in the art will appreciate that additional mobile switching centers may be employed. In addition, one skilled in the art will also appreciate that exemplary cellular mobile radio systems can also operate without the use of base station controllers.
  • the present invention is most applicable to a TDM A environment where the power of a system is limited.
  • An exemplary base station in which the method of the present invention may be implemented was set forth above with respect to FIG. 1.
  • Such a base station operating in a TDMA environment, is commonly associated with a plurality of frequency carriers. Each frequency carrier is divided into a plurality of time slots to which mobile stations are assigned. Returning to FIG. 2, for example, the frequencies associated with an exemplary base station are depicted. Each of the seven frequencies is divided, for explanatory purposes, into eight time slots. Mobile users would be assigned to one or more time slots for transmission purposes.
  • P MCPA When the MCPA has been calibrated to a particular maximum tolerable output power, P MCPA , exceeding that maximum limit results in a loss in linearity. A loss in linearity can cause an increase in spurious emissions from, for example, intermodulation products. P can be limited by any sub-component within the transmitter chain. That is, the maximum tolerable power can be reduced by, for example, limitations of amplifiers, filters, digital-to-analog converters, and/or upconverters. Therefore, it is desirable to limit P MCPA by reducing the margin between the average transmit power over several time slots and P MCPA in order to, for example, reduce the cost of the MCPA.
  • the power control method of the present invention allows for a lower P UCP ⁇ , and, therefore, a lower cost MCPA to be employed by a base station.
  • the present invention does not need to sacrifice quality in order to reduce costs since it is able to maintain sufficient average power.
  • the MCPA of the present invention can accommodate more users than conventional MCPAs by an efficient use of the MCPA's resources.
  • N is the number of users per time slot and x is the speech activity per user.
  • the probability of all users being active is as low as 1/256 or 0.4% .
  • FIG. 4 illustrates a model of the probability of talk spurts and silence periods for exemplary users of the present invention.
  • the probability of n out of y users being active when n approaches y is extremely low. Therefore, even if the maximum transmit power of each user is set such that in the worst case (i.e., all users are active at the same time)P is exceeded, the actual probability of exceeding P MCP ⁇ will be extremely low. However, even though the probability is extremely low, there will be short periods where the desired output power will exceed P MCPA ⁇
  • FIG. 5A illustrates a MCPA 500 according to an exemplary embodiment of the present invention. Similar to multicarrier transmitter 100 of FIG. 1, each of a number of baseband frequency data signals BB]...BB N are forwarded to a corresponding modulator Mod,...Mod N . The modulated baseband signals BB,...BB N are then forwarded to the digital power control modules DPC, ...DPC N . The Radio Control Unit 5650 individually sets the gain of each digital power control module DPC,....DPC N .
  • the Radio Control Unit 5650 receives power command signals 5653 from a Peak Power Suppression Unit 5652.
  • the signals 5653 are power control commands informing the Radio Control Unit 5650 of the actual output level at the transmitter, P , for each carrier and time slot.
  • the Peak Power Suppression Unit 5652 calculates, on a time slot basis, the desired P by assuming the power control commands 5651 would not be modified by the Peak Power Suppression Unit 5652.
  • the Peak Power Suppression Unit 5652 modifies the power control commands for one or several users, if the desired P sum exceeds the maximum tolerable threshold level for the MCPA, P MC flickPA ⁇ ,' in order to keep r p sum less than or equal to P .
  • the actual desired power level signals 5651 are obtained from a conventional open or closed loop power control algorithm.
  • the signals generated by the digital power control modules DPC,...DPC N are forwarded to multipliers Multi 1 ...Multi N where the signals are upconverted to a corresponding carrier frequency.
  • the upconverted signals are then summed by adder 5610.
  • the resultant compound signal is converted from digital to analog by DAC 5620.
  • the analog signal is forwarded to an analog power control module 5660 which has a constant gain, G ana .
  • analog power control module 5660 is illustrated as a single element in FIG. 5A, the functionality of the analog power control module 5660 may be distributed over the analog transmitter chain, i.e., amplifiers, filters and upconverter s, in order to minimize the effect on the noise figure.
  • the Peak Power Supervision Unit 5652 and the Radio Control Unit 5650 can be implemented using any known digital signal processing technology, including a general purpose computer, a collection of integrated circuits and/or application specific integrated circuitry (ASIC).
  • ASIC application specific integrated circuitry
  • FIG. 5B illustrates a MCPA 500' according to another exemplary embodiment of the present invention. Similar to multicarrier transmitter 100 of FIG. 1, each of a number of N baseband frequency data signals BB,...BB N are forwarded to a corresponding modulator Mod, ...Mod N . The modulated baseband signals BB,...BB N are then forwarded to the digital power control modules DPC,...DPC N .
  • the Radio Control Unit 5650' individually sets the gain of each digital power control module DPC ! ...DPC N , such that the total in-phase power sum in to the DAC 5620 equals the full scale range of the DAC, P FS>DAC .
  • the Radio Control Unit 5650' receives power command signals 5653 from a Peak Power Suppression Unit 5652.
  • the signals 5653 are power control commands informing the Radio Control Unit 5650' of the actual output level at the transmitter, P k.out , for each carrier and time slot.
  • the Peak Power Suppression Unit 5652 calculates, on a time slot basis, the desired P by assuming the power control commands 5651 would not be modified by the Peak Power Suppression Unit 5652.
  • the Peak Power Suppression Unit 5652 modifies the power control commands for one or several users, if the desired P sum exceeds the maximum tolerable threshold level for the MCPA, P M Cosmetic handshake, , in order to keep r P sum less than or equal to P MCPA ⁇
  • the actual desired power level signals 5651 are obtained from a conventional open or closed loop power control algorithm.
  • the signals generated by the digital power control modules DPC ,...DPC N are forwarded to multipliers Multi 1 ...Multi N where the signals are upconverted to a corresponding carrier frequency.
  • the upconverted signals are then summed by adder 5610.
  • the resultant compound signal is converted from digital to analog by DAC 5620.
  • the analog signal is forwarded to an analog power control module 5660' which is controlled by an analog power control table stored in the Radio Control Unit 5650' .
  • analog power control module 5660' is illustrated as a single element in FIG. 5B, the functionality of the analog power control module 5660' may be distributed over the analog transmitter chain, i.e. , amplifiers, filters and upconverters, in order to minimize the effect on the noise figure.
  • the Radio Control Unit 5650' obtains, from the power control command signals 5653, the required power level of each carrier at the output of the transmitter P , i.e. , the amount of transmit power required to provide a corresponding mobile station with an acceptable signal.
  • the full scale range of the DAC 5620 is determined at the time of installation of the DAC 5620 in the multicarrier transmitter, the full scale range P FS,DAC of the DAC 5620 and the corresponding code can be programmed into the Radio Control Unit 5650' .
  • the Radio Control Unit 5650' sets the relative power for all carriers in such a way that the in-phase power sum in the digital domain supplied to the DAC 5620 equals the DAC's full scale range.
  • Radio Control Unit 5650' applies an adjustable analog power gain, G ana , for the analog power amplifier 5660' .
  • G ana for the analog power amplifier 5660' .
  • FIG. 6A illustrates a flow diagram of an exemplary embodiment of the present invention.
  • the Peak Power Supervision Unit 5650 selects the present time slot i in block 670.
  • the desired in-phase power sum for time slot i, P sum is calculated in block 672.
  • the value of P sum is comp ⁇ ared to p MCPA . If P sum ⁇ P MCPA then the individual p r ower level commands are allowed to pass to the Radio Control Unit 5650, 5650' (see FIGS. 5A-5B) without manipulation or adjustment (block 680).
  • FIG. 6B illustrates an exemplary embodiment for block 676 of FIG. 6A.
  • a user k is selected out of the total number of users on the time slot i ([1, ... , M ⁇ ).
  • the power of a single speech burst for user k is set to zero. For the following speech burst, the power of a user k+ 1 is set to zero.
  • each user has their power set to zero for example, 1 (or more) out of 8 bursts per speech frame.
  • Conventional error correction techniques such as speech coding and interleaving, are used to mitigate the effects caused by the loss of a single speech burst so as to not compromise overall speech quality.
  • the exemplary method of FIG. 6B effectively spreads quality reductions over multiple users so as to reduce the impact as much as possible on the perceived quality by any given user.
  • FIG. 6C illustrates another exemplary embodiment for block 676 of FIG. 6A.
  • a user k is selected out of the total number of users on the time slot i ([1, ... , ]).
  • the power of user k, P is reduced.
  • the present invention returns to block 672 of FIG. 6A and repeats blocks 674-676 selecting different values of k until P is less than or equal to P MCPA
  • FIG. 6D illustrates another exemplary embodiment for block 676 of FIG. 6A.
  • all users k are selected out of the total number of users on the time slot / ([1, ... , M ⁇ ).
  • the power of each user is either reduced equally or dependent to the power of each user. That is, the power of each user can be reduced by the same percentage (e.g., 20% dB or 20% W) or the same value (e.g., 1 dB or 1 W).
  • the power of each user can be reduced dependent on their current power. For example, users which have higher powers are usually further away from a base station than users with lower powers.
  • an exemplary embodiment of the present invention reduces the power dependent on the present power such that the power of near-users are reduced more than the power of far-users, e.g., inversely proportional to their present power.
  • the power of far-users are reduced more than the power of near-users since signals to the far-users would most probably be transmitted at a higher power than signals transmitted to the near-users.
  • FIG. 6E illustrates another exemplary embodiment for block 676 of FIG. 6A.
  • the user k which has the greatest power is selected. Then in block 676E 2 , the power of user k is reduced.
  • FIG. 6F illustrates another exemplary embodiment for block 676 of FIG. 6 A.
  • the user k which has the greatest perceived signal quality is selected.
  • the user k which has the weakest perceived signal quality may be selected.
  • the power of user k is reduced.
  • the perceived signal quality can be determined, for example, by calculating a signal- to-noise ratio or bit-error rate.
  • CDMA code division multiple access
  • FDMA frequency division multiple access

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Abstract

La présente invention concerne un système et un procédé de commande de puissance d'émission qui utilise une répartition efficace de la puissance de sortie moyenne d'un amplificateur de puissance multi-porteuse ou 'MCPA' (Multi-Carrier Power Amplifier), la puissance de sortie moyenne étant une moyenne pondérée de la puissance réelle sur plusieurs tranches de temps. Périodiquement, en utilisant le système et le procédé de répartition efficace, il y aura de courtes périodes où la puissance de sortie moyenne désirée viendra dépasser la puissance maximale admise du MCPA PMCPA. Ces courtes périodes où la puissance de sortie désirée vient dépasser PMCPA sont traitées par un système et un procédé réduisant la marge entre la puissance totale par tranche de temps et PMCPA. Cette réduction de la marge permet au MCPA de desservir un plus grand nombre d'utilisateurs par tranche de temps que les MCPA conventionnels. Selon une autre réalisation, le MCPA peut desservir le même nombre d'utilisateur qu'un MCPA conventionnel, mais en demandant plus de puissance de sortie pour chaque utilisateur et/ou une utilisation plus rationnelle des ressources du MCPA.
PCT/SE2000/001386 1999-07-08 2000-06-29 Commande de puissance d'emission pour stations de base equipees mcpa WO2001005057A1 (fr)

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Application Number Priority Date Filing Date Title
EP00946677A EP1224745A1 (fr) 1999-07-08 2000-06-29 Commande de puissance d'emission pour stations de base equipees mcpa
AU60398/00A AU6039800A (en) 1999-07-08 2000-06-29 Transmit power control for mcpa-equipped base stations

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US09/349,717 1999-07-08
US09/349,717 US6570929B1 (en) 1999-07-08 1999-07-08 Power control scheme for maximizing carrier signal-to-noise ratio in multicarrier transmitters
US09/360,141 1999-07-26
US09/360,141 US6694148B1 (en) 1999-07-26 1999-07-26 Transmit power control for MCPA-equipped based stations

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WO2001048929A2 (fr) * 1999-12-24 2001-07-05 Nokia Corporation Commande d"un amplificateur de puissance a porteuses multiples
WO2002084935A1 (fr) * 2001-04-17 2002-10-24 Nokia Corporation Procedes pour determiner les gains de differentes porteuses, unites de radiotransmission et modules pour ces unites
WO2005036763A1 (fr) * 2003-10-07 2005-04-21 Radioscape Limited Systeme de modulation par division de frequence orthogonale a codage multicanal
WO2005099116A1 (fr) * 2004-03-30 2005-10-20 Intel Corporation Transmission multiporteuse a bande large
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JP2007528185A (ja) * 2004-03-30 2007-10-04 インテル・コーポレーション 広帯域マルチキャリア送信
EP1793509A1 (fr) * 2005-12-01 2007-06-06 Alcatel Lucent Procédé de réglage de la puissance d'émission pour un système de communication
WO2007067004A2 (fr) * 2005-12-08 2007-06-14 Samsung Electronics Co., Ltd. Terminal et procede de controle de puissance d'emission
WO2007067004A3 (fr) * 2005-12-08 2008-07-31 Samsung Electronics Co Ltd Terminal et procede de controle de puissance d'emission
US7970363B2 (en) 2005-12-08 2011-06-28 Samsung Electronics Co., Ltd. Terminal and method for controlling transmission power

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