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
  • H04W52/52—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
  • H04W52/06—TPC algorithms
  • H04W52/08—Closed loop power control

Definitions

• This invention relates generally to a method and system for communication.
• this invention relates to a method and system for fixed radio terminal communication.
• Radio in the Local Loop cellular systems employing fixed cellular terminals, e.g., GSM/TDMA/WCDMA systems, satellite systems, and Wireless LAN systems.
• RLL Radio in the Local Loop
• the fixed terminals are installed quickly and in a manner such that later reinstallation will not be needed. It is also important that the terminals are installed with as low a path loss as possible to provide a good link budget and thereby minimize the number of base station sites required.
• Fixed radio telecommunication terminals are, depending on the system, installed indoors or outdoors. RLL and satellite systems usually use outdoor terminals in order to provide a good link budget.
• Fixed radio terminals e.g., fixed cellular terminals (FCTs) employed in, e.g., the GSM system, are usually mounted indoors due to environmental factors, e.g., specification and testing of terminals for a limited temperature range, and functional factors, e.g., accessability to parts of the fixed radio terminal.
• FCTs fixed cellular terminals
• some of the radio parts are preferably mounted outdoors.
• the antenna unit includes an antenna cable and an antenna.
• the antenna unit also includes an antenna amplifier and a device for determining the mode of operation of the fixed radio terminal.
• the antenna unit also includes a frequency converter for converting received high frequency signals to low frequency signals or for converting signals for transmission from a low frequency to a high frequency, depending on the mode of operation.
• the mode of operation may be determined using a ramp detector to detect a transmission ramp.
• a control signal sent from the fixed radio terminal may be used as an indication of the mode.
• the output power may be adjusted by either the amplifier in the fixed radio terminal, taking into account a known constant amplification factor in a linear or a non-linear antenna amplifier, or by the antenna amplifier in the antenna unit based on power control commands received from the fixed radio terminal or the base station.
• the power control commands can either contain absolute values or values relative to the current output power.
• FIG. 1 illustrates a communication system according to a first aspect of the invention
• FIG. 2 illustrates details of an exemplary fixed radio terminal
• FIG. 3 illustrates an exemplary antenna unit according to a second embodiment
• FIG. 4 illustrates details of an antenna amplifier according to the second embodiment
• FIG. 5 illustrates an exemplary antenna unit according to a third embodiment
• FIG. 6 illustrates details of an exemplary antenna amplifier and frequency converter according to the third embodiment
• FIG. 7 illustrates a communication system according to a second aspect of the invention.
• FIG. 8 illustrates a method for receiving and transmitting signals according to exemplary embodiments.
• FIG. 1 illustrates a communication system with a fixed radio terminal, e.g., a FCT 100, mounted indoors and an antenna unit 200 mounted outdoors.
• the FCT 100 may be connected to a telephone 500.
• the FCT 100 may include a data adaptor 105 for fax and data to facilitate communication with a personal computer 400 via a modem 300.
• the FCT 100 is connected to the antenna unit 200 via, e.g., a coaxial cable. It should be appreciated that the antenna unit 200 may be mounted indoors, e.g., if the terminal is placed close to the base station.
• FIG. 2 illustrates details of an exemplary FCT according to the first aspect.
• FCT 100 includes a power supply 110, radio parts including a high frequency radio, e.g., a 3.5 GHz radio 120, and a GSM radio 130, GSM digital parts 140 and a line interface 150.
• the FCT 100 may also include other parts, e.g., a subscriber interface module (SIM) card (not shown).
• SIM subscriber interface module
• the 3.5 GHz radio 120 receives signals in a 3.5 GHz band from the antenna unit
• the received signals are converted from the 3.5 GHz band to a GSM band (900/1800/1900 MHZ) and delivered to the GSM radio 130. This conversion may be performed, e.g., in the 3.5 GHz radio 120.
• the signal received by the GSM radio 130 is delivered to the GSM digital parts 140 for processing.
• the line interface 150 forms the interface between the GSM digital parts 140 and, e.g., the modem 300 or phone 500.
• the data adaptor 105 may be physically attached to the line interface 150 or connected via a cable to the line interface 150.
• Control signals such as Tx and Rx signals, clock signals, phase lock loop (PLL) control signals, power control commands, etc., are exchanged, e.g., between the antenna unit 200 and the GSM digital parts 140 via the 3.5 GHz radio 120 and the GSM radio 130.
• the power supply 110 may be, e.g., a 12 V battery.
• the antenna unit 200 includes an antenna and an antenna cable.
• a short antenna cable e.g., 2-5 m, can be used to connect the antenna unit to the 3.5 GHz radio 120. If the 3.5 GHz radio 120 is mounted indoors, then the antenna unit would be located close to the 3.5 GHz radio 120, e.g., on a window. Due to the short cable, and thus the limited freedom in choosing a spot to locate the antenna unit, this configuration is best suited for places where the link budget is good, e.g., close to the serving base station.
• FIG. 3 illustrates a communication system in which an antenna amplifier is mounted outdoors with an antenna in an antenna unit 250.
• FIG. 4 illustrates an exemplary antenna unit according to the second embodiment.
• the antenna unit 250 includes a power amplifier (PA) 260, a low noise amplifier (LNA) 270, a power supply 280, and an antenna 290. Although illustrated and described as a directional antenna, the antenna 290 may also be another type of antenna.
• PA power amplifier
• LNA low noise amplifier
• Signals received by the directional antenna 290 are delivered to the LNA 270 for amplification.
• Signals for transmission by the directional antenna 290 are amplified by the PA 260 and delivered to the directional antenna 290.
• a power supply 280 supplies power to the antenna.
• the power supply 280 may, e.g., be a battery.
• the antenna unit 250 may receive power from the power supply 110 of the FCT 100.
• the antenna unit 250 needs to be able to determine whether the FCT 100 is in a receiving mode or a transmission mode. This determination may be made in several ways. For example, a ramp detector may be used in the antenna unit 250 to sense when the transmission ramp from the FCT 100 starts and ends. Alternately, the DC voltage levels in the power feeding of the antenna unit 250 can be toggled between two values, one representing transmission, and one representing reception, thus creating a binary control signal under the control of, e.g., a microprocessor in the FCT 100.
• a ramp detector may be used in the antenna unit 250 to sense when the transmission ramp from the FCT 100 starts and ends.
• the DC voltage levels in the power feeding of the antenna unit 250 can be toggled between two values, one representing transmission, and one representing reception, thus creating a binary control signal under the control of, e.g., a microprocessor in the FCT 100.
• a databus can be used to convey control information between, e.g, a microprocessor in the FCT 100 and the antenna unit 250, indicating whether the FCT is in the receiving or transmitting mode.
• the antenna unit 250 also adjusts the output power.
• a linear amplifier that transparently amplifies the signal may be used as the PA 260.
• the PA 260 may be a non-linear amplifier and the FCT 100 and the antenna unit 250 can be calibrated against each other to provide linear characteristics. This is known as "feed forward linearization".
• the power adjustment may be made based on network feedback, i.e., power control commands received from the base station in response to signal strengths measured by the base station.
• power control commands may be provided over a communication bus, or a similar device, from the FCT 100 to the antenna unit 250.
• the amplification of the PA 260 and the cable losses are known to the FCT 100, and the FCT generates power control commands, taking these factors into account.
• the commands may either contain absolute values, instructing the PA 260 to provide a particular amount of amplification, or the commands may contain values relative to the current output power, instructing the PA 260 to adjust the output power by a certain amount.
• output power adjustments may be made in the FCT 100 using, e.g., network feedback or power control commands from a microprocessor in the FCT 100 and/or a linear amplifier or feed forward linearization.
• a frequency converter instead of an antenna amplifier, may be used to minimize cable loss by converting received high frequency signals to low frequency signals or converting signals for transmission from a low frequency to a high frequency.
• the frequency converter can be mounted outside with the antenna in the antenna unit.
• FIG. 5 illustrates an exemplary communication system according to the third embodiment.
• the communication system shown in FIG. 5 is similar to that shown in FIG. 3, except that the antenna unit 255 comprises a frequency converter in addition to the antenna amplifier. It will be appreciated, however, that the antenna unit may comprise only a frequency converter, without an antenna amplifier.
• the internal clock of the FCT 100 can be transmitted to the outdoor antenna unit 255.
• the frequency converter converts a received signal having a high frequency into a signal having a low frequency and/or converts a signal at a low frequency to a signal at a high frequency for transmission. In this manner, the frequency converter minimizes high frequency loss in the cable and permits a longer cable to be used.
• FIG. 6 illustrates details of an antenna unit according to the third embodiment.
• the antenna unit 255 is the same as the antenna unit 250 shown in FIG. 4, except that it includes a frequency converter 265 in addition to the PA 260 and the LNA 270.
• Using an antenna amplifier and/or a frequency converter minimizes high frequency loss if a long cable is used to connect the antenna and the FCT 100.
• the 3.5 GHz radio 120, the GSM radio 130, the GSM digital parts 140, the line interface 150, and other parts, e.g., an SIM card may be colocated with the antenna.
• a data adaptor (FDA) 160 and a power supply (PS) 170, 180 may be located indoors to facilitate installation and replacement.
• FDA data adaptor
• PS power supply
• an FCT with an antenna 600 includes the 3.5 GHz radio 120, the GSM radio 130, the GSM digital parts 140, the line interface 150, and other parts, e.g., the SIM card.
• all the radio parts are located outdoors, and other devices are located indoors.
• FIG. 8 illustrates a method for communicating according to exemplary embodiments. The method begins at step 800 at which the mode of operation of the fixed radio terminal is determined. This determination is made, e.g., by a device colocated with the antenna if the antenna amplifier is also colocated with the antenna. Otherwise, this determination is made by the digital parts of the fixed radio terminal.
• the best way to provide a low line cost is to place the antenna so that the path loss is minimized. This maximizes the link budget and minimizes the cost for the infrastructure since fewer base stations are needed. According to exemplary embodiments, this is made possible by mounting the antenna separately from the fixed terminal, e.g., outdoors, colocated with an antenna amplifier and/or a frequency converter. Also, the fixed radio terminal may be located outdoors, with some parts located indoors.

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

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=23919521

Family Applications (1)

Country Status (4)

Citations (6)

• 2001
  • 2001-01-12 AU AU2001228961A patent/AU2001228961A1/en not_active Abandoned
  • 2001-01-12 AR ARP010100145A patent/AR029028A1/es unknown
  • 2001-01-12 WO PCT/SE2001/000055 patent/WO2001052444A1/en active Application Filing
  • 2001-01-12 UY UY26532A patent/UY26532A1/es not_active Application Discontinuation

Patent Citations (6)

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