EP1157480A1 - Transmission de signal a amcr utilisant des rapports de signaux intrabande et hors bande - Google Patents

Transmission de signal a amcr utilisant des rapports de signaux intrabande et hors bande

Info

Publication number
EP1157480A1
EP1157480A1 EP00913876A EP00913876A EP1157480A1 EP 1157480 A1 EP1157480 A1 EP 1157480A1 EP 00913876 A EP00913876 A EP 00913876A EP 00913876 A EP00913876 A EP 00913876A EP 1157480 A1 EP1157480 A1 EP 1157480A1
Authority
EP
European Patent Office
Prior art keywords
cdma
signal
operational
band components
power
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Withdrawn
Application number
EP00913876A
Other languages
German (de)
English (en)
Inventor
Lindsay A. Weaver, Jr.
Brian K. Harms
Anthony C. K. Soong
Bruce S. Schwartz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Qualcomm Inc
Original Assignee
Qualcomm Inc
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
Application filed by Qualcomm Inc filed Critical Qualcomm Inc
Publication of EP1157480A1 publication Critical patent/EP1157480A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • 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
    • 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

Definitions

  • the present invention relates to Code Division Multiple Access
  • CDMA Code Division Multiple Access
  • the present invention includes, but is not limited to, a novel and improved CDMA base station that generates a ratio of in-band to out-of-band signal strength for use in base station transmission control.
  • CDMA Code Division Multiple Access
  • a CDMA base station transmits a CDMA signal to numerous CDMA communications devices, such as wireless telephones.
  • the CDMA signal is comprised of numerous individual user signals.
  • the CDMA base station generates the CDMA signal by encoding each individual user signal with a unique spreading sequence, such as a pseudo random sequence.
  • the CDMA base station then adds the encoded user signals together to form the CDMA signal.
  • CDMA base stations generate undesirable noise in the form of signal power outside of the frequency band of the CDMA signal. This undesirable power is referred to as out-of-band signal power.
  • Out-of-band signal power is a problem because it interferes with other signals in the neighboring frequency bands. These other signals are disrupted by the interference. Government agencies, such as the Federal Communications Commission in the United States, strictly regulate the interference caused by out-of-band signal power.
  • Test equipment is used to calculate a ratio for a test CDMA signal transmitted by the base station.
  • the ratio represents the in-band signal power versus the out-of-band signal power.
  • the base station transmit power is adjusted during the testing so the ratio is below a maximum value with a margin for some ratio increase under the maximum value.
  • This usuallu Unfortunately the ratio is not calculated and is not used during normal base station operation in the field.
  • Test equipment is used to calculate the ratio, and base stations are not equipped to calculate the ratio in the field. Thus, the ratio is not automatically generated and used to control operation in the field where changes in temperature and load alter base station operation.
  • CDMA systems would be improved through transmission at a power level just below the point where out-of-band signal power becomes a problem. Transmission at this power level would optimize the range and capacity of the base station.
  • the above-described problem is solved with CDMA transmission control technology.
  • the CDMA transmission control technology allows a CDMA base station to operate at an optimized power level without generating improper amounts of out-of-band noise.
  • the optimized power level extends the range and capacity of the base station.
  • the increased range and capacity is passed on to the end-user in the form of decreased costs and increased functionality.
  • a transmitted CDMA signal has in-band components and out-of-band components.
  • Transform logic automatically generates a ratio of the signal strength of the in-band components versus the out-of-band components.
  • control logic uses the ratios to generate metric signals that indicate if transmit power should be limited and that indicate excess forward link capacity. The invention eliminates the need to leave a margin during testing for future ratio increases. The elimination of this margin allows operation at higher power levels.
  • FIG. 1 is a block diagram of a CDMA system with transmission control logic
  • FIG. 2 is a graph illustrating the frequency spectrum of a CDMA signal
  • FIG. 3 is a block diagram of a CDMA system with transmission control logic
  • FIG. 4 is a block diagram of a CDMA base station with transmission control logic
  • FIG. 5 is a is a graph illustrating the frequency spectrum of portions of a
  • CDMA signal used for transmission control
  • FIG. 6 depicts a logical table used for transmission control.
  • FIGS. 1-2 CDMA Transmission Control Technology - FIGS. 1-2
  • FIG. 1 depicts a CDMA signal 100, a CDMA transmitter 101, an RF CDMA signal 102, and a CDMA receiver 103.
  • CDMA is a spread-spectrum communications technology. Some versions of CDMA are specified by standards, such as IS-95 approved by the Telecommunications Industry Association.
  • the CDMA signal 100 could be any CDMA signal, such as the signal produced by a cell site modem in a CDMA base station.
  • the CDMA receiver 103 could be any CDMA device capable of receiving a CDMA signal, such as a wireless CDMA telephone.
  • the CDMA transmitter 101 transmits the CDMA signal 102 to the CDMA receiver 103.
  • the CDMA transmitter 101 could be any CDMA transmission device that includes transmit control logic 116.
  • One example of the CDMA transmitter 101 is a CDMA base station.
  • the transmit control logic 116 in the CDMA transmitter 101 generates a ratio based on the signal strength of in-band versus out-of-band portions of the CDMA signal 102. Signal strength can be measured in various ways with examples being power, voltage, or energy. In some examples of the invention, the transmit control logic 116 generates metric signals that indicate if transmit power should be limited and that indicate excess forward link capacity.
  • FIG. 2 illustrates the frequency spectrum of a CDMA signal.
  • the vertical axis represents signal power, and the horizontal axis represents frequency.
  • the desired in-band signal power is contained within the bandwidth defined by corner frequencies around a center frequency.
  • a typical example is a 1.25 MHz bandwidth centered about a 1.96 GHz center frequency with corner frequencies at (1.96 GHz - 625 KHz) and (1.96 GHz + 625 KHz).
  • the signal power drops significantly outside of the bandwidth, but some undesired out-of-band signal power is still present and is shaded on FIG. 2.
  • Out-of band signal power is undesirable because it represents wasted power that interferes with other signals in neighboring frequency bands.
  • FIGS. 3-5 depict a specific example of a CDMA system that uses the transmission control technology of the present invention, but those skilled in the art will recognize numerous other types of CDMA systems that are applicable to the invention described above.
  • FIG. 3 depicts a communications system 304 that is connected to the CDMA communications system 306.
  • the CDMA communications system 306 communicates with CDMA communications devices 308.
  • the CDMA communications system 306 is comprised of a switching center 310 and a base station 312.
  • the communications system 304 exchanges communications signals 305 with the switching center 310.
  • the switching center 310 exchanges communications signals 311 with the base station 312.
  • the base station 312 exchanges wireless CDMA communications signals 307 over the air interface with the CDMA communications devices 308.
  • the invention is depicted using an air interface, other transmission media could also be used, such as RF cable, power lines, or telephone lines.
  • the communications system 304 could be any communications system capable of exchanging communications signals 305 with the CDMA communications system 306.
  • the communications system 304 is typically a conventional public telephone network, but could also be many other networks, such as a local area network, wide area network, or internet.
  • the switching center 310 could be any device that provides an interface between the base station 312 and the communications system 304. Typically, numerous base stations are connected to the communications system 304 through the switching center 310, but the number of base stations has been restricted for the purpose of clarity.
  • the base station 312 exchanges wireless CDMA signals 307 with the CDMA communications devices 308.
  • the base station 312 includes transmit control logic 316 that generates power and capacity metric signals based on ratios of the in-band versus out-of-band power in the CDMA signals 307. Those skilled in the art could adapt the base station 312 from known systems, such as the base stations provided by Qualcomm, Inc. of San Diego, California.
  • the CDMA communications devices 308 exchange wireless CDMA signals 307 with the base station 312. Typically, numerous CDMA communications devices exchange signals with the base station 312, but the number of communications devices has been restricted for the purpose of clarity.
  • the typical CDMA communications device is a mobile telephone, but other CDMA communications devices are also possible, such as fixed wireless devices, data terminals, set-top boxes, or computers.
  • the CDMA communications devices 308 communicate through the CDMA communications system 306 with the communications system 304 or with each other.
  • the transmit control logic 316 On the forward link communications path from the communications system 304 to the CDMA communications devices 308, the transmit control logic 316 generates various ratios based on the in-band versus out-of-band power in portions of the CDMA signal 307. The transmit control logic 316 compares the ratios to pre-determined values that represent the point where out-of-band signal power becomes improper.
  • the transmit control logic 316 generates a power metric signal and a capacity metric signal based on the comparison. If one of the calculated ratios exceeds its associated pre-determined value, then the power metric signal indicates that the transmit power of the base station 312 should be limited.
  • the capacity metric signal indicates an estimate of the excess forward link capacity of the base station 312. The estimate is typically given in a number of additional simultaneous calls that can be handled by the base station 312 without one of the calculated ratios exceeding its associated pre-determined value.
  • FIG. 4 depicts the base station 312 of FIG. 3 receiving the communications signals 311 and transmitting the CDMA communications signals 307.
  • the base station 312 is comprised of the following elements connected in series: cell site modems 421, digital-to-analog conversion and filter 422, up-converter 423, gain limiter 424, power amplifier 425, and antenna 426.
  • the transmit control logic 316 is coupled to the path between the power amplifier 425 and the antenna 426 to monitor the transmitted CDMA signal 307.
  • the transmit control logic 316 is comprised of down-converter 432, transform logic 434, and control logic 436. Aside from the transmit control logic 316, those skilled in the art are familiar with these elements and their operation.
  • the cell site modems 421 produce a baseband CDMA signal and provide it to the digital-to-analog conversion and filter 422.
  • the digital-to-analog conversion and filter 422 converts the CDMA signal to analog and filters out components outside of the desired bandwidth.
  • the digital-to-analog conversion and filter 422 provides the CDMA signal to the up-converter 423.
  • the up-converter 423 modulates the CDMA signal with intermediate and radio frequencies to form a Radio Frequency (RF) CDMA signal, and typically generates undesirable out-of-band signal power.
  • the up-converter 423 provides the RF CDMA signal to gain limiter 424.
  • the gain limiter 424 limits the power level of the RF CDMA signal based on a power metric signal 437.
  • the gain limiter 424 provides the RF CDMA signal to the power amplifier 425.
  • the power amplifier 425 amplifies the RF CDMA signal, and typically generates undesirable out-of-band signal power.
  • the power amplifier 425 provides the amplified RF CDMA signal to the antenna 426 for transmission the RF CDMA signal 307.
  • the down-converter 432 of the transmit control logic 316 monitors the CDMA signal 307.
  • the down-converter 432 de-modulates the RF CDMA signal 307 to form a baseband CDMA signal.
  • the down-converter 432 provides the baseband CDMA signal to the transform logic 434.
  • FIG. 5 illustrates the frequency spectrum of the baseband CDMA signal received by the transform logic 434.
  • FIG. 5 is an ideal representation of the signal.
  • the vertical axis represents signal power, and the horizontal axis represents frequency.
  • the desired in-band signal power is contained within the bandwidth defined by corner frequencies around a center frequency.
  • Bandwidth segments 551-557 are shown.
  • Bandwidth segment 551 is in-band, and bandwidth segments 552-557 are out- of-band.
  • the power in each bandwidth segment 551-557 is shaded on FIG 5.
  • the segments depicted on FIG. 5 are shown for illustrative purposes, and the actual segments used could vary in number or bandwidth. The segments could also be determined based on industry standards
  • the transform logic 434 performs Fast-Fourier transforms to generate values representing the power in each bandwidth segment 551-557. Those skilled in the art are familiar with the logic required to perform such Fast - Fourier transforms.
  • the transform logic 434 then generates ratio values that will depend on the segments used. In this example, the following ratio values are generated: ratio 1 - bandwidth segment 551 power/bandwidth segment 552 power; ratio 2 - bandwidth segment 551 power/bandwidth segment 553 power; ratio 3 - bandwidth segment 551 power/bandwidth segment 554 power; ratio 4 - bandwidth segment 551 power/bandwidth segment 555 power; ratio 5 - bandwidth segment 551 power/bandwidth segment 556 power; ratio 6 - bandwidth segment 551 power /bandwidth segment 557 power.
  • the transform logic 434 generates a ratio signal 435 that indicates the ratio values and transfers the ratio signal 435 to the control logic 436.
  • the control logic 436 compares each of the ratio values to an associated predetermined maximum value for the particular ratio.
  • the control logic 436 determines if any of the calculated ratios exceed their respective maximum values.
  • FIG. 6 depicts a logical table containing the ratio values 1-6, the respective maximum values, an indication if the ratios exceed the maximum values, and the difference between the ratios and the maximum values.
  • the letters A-G that are listed in the table for the power ratio entries represent actual power measurements.
  • the letters H-M that are listed in the table for the maximum value entries represent actual maximum values that can be readily obtained in standard industry publications, such as IS-97 by the Telecommunication Industry Association.
  • the Federal Communications Commission also publishes maximum ratio values.
  • the control logic 436 of the base station 312 generates a power metric signal 437 and transfers it to gain limiter 424.
  • the power metric signal 437 sets a flag in the gain limiter 424 if one of the ratios exceeds its maximum value.
  • the flag causes the gain limiter 424 to limit the transmit power of the base station 312.
  • the power metric signal 437 clears the flag when none of the ratios exceed their maximum values. In this fashion, the transmit power of the base station 312 is optimized to the point set by the maximum ratio values.
  • the control logic 436 of the base station 312 generates a capacity metric signal 438 and transfers it to a base station control system (not shown).
  • the capacity metric signal 438 indicates an estimate of the excess forward link capacity of the base station 312.
  • the control logic 436 determines the average difference between the measured ratios and the maximum values and translates the difference into a number of additional simultaneous calls that the base station 312 can handle without one of the calculated ratios exceeding its associated pre-determined value.
  • the base station control system can determine whether or not to block call hand-offs or new calls based on the capacity metric signal 438. In this fashion, the number of simultaneous calls handled by the base station 312 is optimized to the point set by the maximum ratio values.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Transmitters (AREA)

Abstract

L'invention concerne une technologie (316) de commande de transmission de signal à AMCR. Un signal (307) à AMCR transmis comporte des composantes intrabandes et des composantes hors bande. Une logique de commande d'émission (316) produit automatiquement un rapport d'intensité de signal des composantes intrabandes sur composantes hors bande. Dans certaines formes de réalisation de l'invention, une logique de commande (436) produit un signal métrique de puissance d'émission en fonction de ce rapport. Dans d'autres formes de réalisation de l'invention, une logique de commande (436) détermine une capacité de liaison aval excédentaire en fonction du rapport. La technologie (166) de commande de transmission à AMCR peut être mise en oeuvre dans une station de base (312) à AMCR.
EP00913876A 1999-03-10 2000-03-10 Transmission de signal a amcr utilisant des rapports de signaux intrabande et hors bande Withdrawn EP1157480A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US26520699A 1999-03-10 1999-03-10
PCT/US2000/006256 WO2000054429A1 (fr) 1999-03-10 2000-03-10 Transmission de signal a amcr utilisant des rapports de signaux intrabande et hors bande
US265206 2002-10-04

Publications (1)

Publication Number Publication Date
EP1157480A1 true EP1157480A1 (fr) 2001-11-28

Family

ID=23009479

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00913876A Withdrawn EP1157480A1 (fr) 1999-03-10 2000-03-10 Transmission de signal a amcr utilisant des rapports de signaux intrabande et hors bande

Country Status (8)

Country Link
EP (1) EP1157480A1 (fr)
KR (1) KR100649922B1 (fr)
CN (1) CN1343397A (fr)
AU (1) AU3523700A (fr)
BR (1) BR0008805A (fr)
CA (1) CA2364397A1 (fr)
HK (1) HK1044084A1 (fr)
WO (1) WO2000054429A1 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5475861A (en) * 1992-07-01 1995-12-12 Motorola, Inc. Method for controlling transmission power in a communication system
JP2718398B2 (ja) * 1995-06-30 1998-02-25 日本電気株式会社 Ｃｄｍａ基地局送信装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0054429A1 *

Also Published As

Publication number Publication date
KR100649922B1 (ko) 2006-11-24
WO2000054429A1 (fr) 2000-09-14
CN1343397A (zh) 2002-04-03
AU3523700A (en) 2000-09-28
BR0008805A (pt) 2002-02-13
KR20010103047A (ko) 2001-11-17
CA2364397A1 (fr) 2000-09-14
HK1044084A1 (zh) 2002-10-04

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