Patent Description:
Prior to the present teachings, the process of setting transmit power for individual carriers was manual. In a communication system that uses different carriers, power levels have to be adjusted and tuned to account for varying attenuation in a transmission path the adjustments are typically done manually. The attenuation may be due to non-linear characteristics of the path specific attenuation. In a satellite-based communication system, this could be due to non-linear Radio Frequency Transmitter (RFT) flatness. In any communication system, this could also be due to the carrier taking a different transmission path due to redundancy available for different components in the path - including, but not limited to different cables, switches, splitters, wave guides etc..

In existing systems, the carrier power setting is a manual task every time any component in the transmission path changes, or every time any carrier is modified. Components in the path can be, but not limited to, modulators, cables, switches, splitters, wave guides etc. In operational systems, carrier measurement data from installed test or customer terminal base is gathered over a couple of days of period to fine tune the carrier power further. <CIT> describes a satellite transponder architecture employing digital signal processing. A power monitor samples the data stream of carrier frequency samples on board the transponder and computes a power level for each of the carriers. <CIT> describes an automatic transmission level control device. <CIT> describes power control in a multi-carrier radio transmitter.

This Summary is provided to introduce a selection of concepts in a simplified form that is further described below in the Detailed Description.

Any, satellite based or other, communication system that requires multiple carriers and needs to adjust a transmit power of those carriers to account for possible variations over time may use the present teachings. The adjustment to a transmit power may be due to carrier changes or component changes in the transmission path. The improvements and benefits of using an Automatic Carrier Power Setting (ACPS) in the system are:.

A system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions. One general aspect includes a method for compensating for attenuation of carrier power by a transmission path. The method includes defining a path from a gateway to a measurement tap, where the path may include an output port of the gateway and path components used to reach the measurement tap; sweeping, in bands, an RF spectrum served by the RFT by sending a signal at a respective band and a band power from the output port over the path; measuring, at the measurement tap, a power metric for each of the bands; capturing, for each of the bands, power level (PL) data including a frequency start of the respective band, a frequency end of the respective band, the respective band power and the respective power metric at the measurement tap; and setting a carrier power level (CPL) of a carrier having a frequency start and a frequency end, where the CPL is based on the PL data associated with one more of the bands included in the frequency start and the frequency end, where the path components may include one or more connecting cables, one or more switches, and one or more equipment in the path. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

Implementations may include one or more of the following features. The method where the band power of each of the bands is same and a frequency range of each of the bands is same. The measurement tap may include an antenna flange of the RFT. The path may include a satellite. The measurement tap may be disposed along an uplink from the RFT to a satellite. The measurement tap may include an antenna flange of a receiver antenna. The method may include changing the path components; and updating the PL data and the CPL to reflect the changing. The carrier may include a plurality of carriers, and for each of the carriers the CPL is computed. The setting may include computing the CPL based on an area under a curve of the PL data from the frequency start to the frequency end. The method further may include transmitting over the path by varying a desired power level of the carrier at the measurement tap based on the CPL. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

One general aspect includes a system to compensate for attenuation of carrier power by a transmission path. The system includes a path from a gateway to a measurement tap, where the path may include an output port of the gateway and path components used to reach the measurement tap; a power level module to sweep, in bands, an RF spectrum served by the RFT by sending a signal at a respective band and a band power from the output port over the path, to capture, for each of the bands, power level (PL) data including a frequency start of the respective band, a frequency end of the respective band, the respective band power and a respective power metric at the measurement tap; and to set a carrier power level (CPL) of a carrier having a frequency start and a frequency end. The system also includes a measurement module to measure, at the measurement tap, the power metric for each of the bands; where the CPL is based on the PL data associated with one more of the bands included in the frequency start and the frequency end, where the path components may include one or more connecting cables, one or more switches, and one or more equipment in the path. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods. Additional features will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of what is described.

In order to describe the manner in which the above-recited and other advantages and features may be obtained, a more particular description is provided below and will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments and are not, therefore, to be limiting of its scope, implementations will be described and explained with additional specificity and detail with the accompanying drawings.

The present teachings may be a system, a method, and/or a computer program product at any possible technical detail level of integration.

Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as SMALLTALK, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages.

These computer readable program instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

Reference in the specification to "one embodiment" or "an embodiment" of the present invention, as well as other variations thereof, means that a feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment", as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment.

The present teachings set carrier power automatically to account for RFT flatness and other variability of signal attenuation over different transmission paths based on calibration data. The calibration data may be collected and captured at a commissioning of a gateway, a Radio Frequency Transmitter (RFT) equipment at the gateway, or a component in a Tx path.

<FIG> illustrates a transmission path up to an RFT according to various embodiments.

A satellite communication system <NUM> may include a Gateway <NUM>, Tx path components <NUM> and an RFT <NUM>. The Tx path components <NUM> connect an output port <NUM> of the gateway <NUM> with the RFT <NUM>. The Tx path components <NUM> may include cables, switches and other Tx components. In the system <NUM>, the measurements of the measurement module may be used to vary power at the output port <NUM> of the gateway <NUM> for a given path and carrier to achieve a desired output power at a measurement tap per a Link Budget calculation.

An output power metric may be measured with a measurement module <NUM> at a measurement tap. The output power metric may be captured in the form of Carrier Power Level (CPL), path attenuation, RFT output power or any other related measurement that is usable to derive the power at the output port <NUM> of the gateway <NUM> for a given path and carrier. In some embodiments, there can be multiple/redundant paths to a measurement tap differentiated by one or more of the output port <NUM>, the Tx path components <NUM> or combinations thereof. In some embodiments, a gateway <NUM> may have multiple output ports <NUM>. Components of the system <NUM> defining each of the multiple paths may be represented as a unit.

The path <NUM> may be defined based on a selection of a measurement tap. The measurement tap may be at an antenna flange of the RFT <NUM>. As such, the path <NUM> includes the output port <NUM>, the Tx path components <NUM> and the measurement tap (antenna flange of the RFT <NUM>). For example, the path <NUM> may include an output port <NUM>, Tx path components <NUM> (including connecting cables, switches, any other equipment in the path) up to a Traveling-wave tube amplifier (TWTA) connecting to the RFT <NUM> antenna flange.

In some embodiments, the measurement tap may be disposed along a travel path of uplink <NUM> radiated from the RFT <NUM>. The path <NUM> may be defined as the output port <NUM>, the Tx path components <NUM>, the RFT <NUM> and the uplink <NUM> measurement tap.

In order to obtain power level data <NUM> based on measured data along each path in the system <NUM>, a power level module <NUM> at the gateway <NUM> may help output a carrier of desired size based on a granularity of frequency bands for which measurements are needed. At the desired granularity of frequency bands for a carrier size, the gateway <NUM> may sweep an entire Radio Frequency (RF) spectrum that the RFT <NUM> can serve. In some embodiments, a Carrier Power Level (CPL) for each measurement of each of the multiple paths may be computed and stored as power level data <NUM> by the power level module <NUM>. The multiple paths may provide different redundancy paths while in operation and measurements for each of the multiple paths may be noted as calibration results. The power level module <NUM> may receive the power metrics from the measurement module <NUM>.

In some embodiments, a satellite may support adjustment and tuning of carrier power to account for non-linearity caused due to satellite transponders. Some satellite systems lack that capability.

<FIG> illustrates a transmission path including a satellite and a UE according to various embodiments.

A satellite communication system <NUM> may include a Gateway <NUM>, Tx path components <NUM> and a RFT <NUM>. A path <NUM> may connect the output port <NUM> of the gateway <NUM> with a receiver antenna <NUM>. The path <NUM> may include the output port <NUM>, the Tx path components <NUM>, the RFT <NUM>, the uplink <NUM>, the satellite <NUM>, a downlink <NUM> and an antenna flange of the receiver antenna <NUM>. In such embodiments, the antenna flange of the receiver antenna <NUM> as the measurement tap for the path <NUM>. Components of the path <NUM> included in defining the path <NUM> may be represented as a unit. The Tx path components <NUM> may include cables, switches and other Tx components. In some embodiments, there can be multiple, possibly redundant, paths to connect the gateway <NUM> to the receiver antenna <NUM>. The receiver antenna <NUM> may be installed and enabled in different spotbeams or shaped beams to perform a local measurement with a measurement module <NUM> for the path <NUM>.

In some embodiments of the system <NUM>, a measurement tap may be desired at an input port UE <NUM>. In some embodiments of the system <NUM>, a measurement tap may be desired along a downlink <NUM>.

In some embodiments, the local measurements may be sent back to the gateway <NUM> via satellite communications, terrestrial communications, or the like. A proper Carrier Power Level (CPL) at different frequencies may be stored as power level data <NUM> for each of the multiple paths <NUM> based on the local measurement made with the measurement module <NUM>.

The present teachings may record measurements for a carrier size based on granularity of measurements needed. Using larger carrier sizes results in fewer measurements but may hide non-linearities within a frequency range of the carrier. Using smaller carrier sizes during calibration process results in a larger dataset that may capture finer non-linearities of the attenuations in the path.

<FIG> illustrates calibration result data for multiple paths according to various embodiments.

<FIG> illustrates a CPL measurement as a plot illustrating:.

In <FIG>, the dBm/kHz or dBm/MHz gateway output power is shown on a vertical axis for paths <NUM>-<NUM> (depths axis) for an RFT frequency spectrum, here <NUM> to <NUM> (horizontal axis). The illustration may be captured as a configuration in a convenient format, for example, a list, a table in a database, csv, json, XML or the like. The granularity of the frequency bands, Tx or Rx, in the configuration may be implementation specific. The granularity may be uniformly stepped, for example, <NUM>, <NUM>, <NUM>, <NUM> or the like. The granularity stepping need not be uniform. For example, a frequency band of a first granularity may span <NUM> and a second different and non-overlapping granularity may have a frequency band that spans <NUM>. The frequency spectrum of a carrier or an RFT frequency spectrum may be non-contiguous.

In this specific example, gateway output power as measured at a measurement tap, for example, at an antenna flange of the RFT, along an uplink, along a downlink, an antenna flange of a receiver antenna, a UE input port, or the like. The metric measured at the measurement tap may be captured in the form of path attenuation, RFT output power or any other related measurement that can be used to derive required gateway transmit power for a frequency band.

For ease of measurement, a measurement may be performed by varying the RFT Input by sweeping a carrier of a desired band/granularity from start to end of an RFT's supported spectrum. The carrier power may be kept constant during the sweep. A deviation from desired power at the measurement tap, for example, the input of antenna flange at the RFT, at a UE or the like can be measured. A pretty good estimate of required transmit powers at the gateway may be obtained after a sweep. Subsequent sweeps may be used to get more accurate results that, for example, correct for measurement difference during a previous sweep, for example, the immediately preceding sweep.

After selecting a path and a frequency range, a gateway component may adjust the transmit power per the power level data. In some embodiments, a gateway may compute required carrier power based on size and location of the carrier on RF spectrum. Carrier power may be computed as an area under the curve for a given path the carrier is to take between the start and the end frequency of the carrier. A desired power level of a Tx carrier at a measurement tap may be provided by a link budget table.

<FIG> illustrates a method for compensating for attenuation of carrier power by a transmission path according to various embodiments.

A method <NUM> for compensating for attenuation of carrier power by a transmission path may include an operation <NUM> to define a path from a gateway to a measurement tap. The method <NUM> may include an operation <NUM> to sweep an RF spectrum by sending a signal at a respective band and a band power from the output port over the path. The method <NUM> may include an operation <NUM> to measure, at the measurement tap, a power metric for each of the bands. The method <NUM> may include an operation <NUM> to capture, for each of the bands, PL data including the respective power metric at the measurement tap. The method <NUM> may include an operation <NUM> to set a CPL of a carrier having a frequency start and a frequency end based on the PL data associated with one more of the bands included in the carrier. The method <NUM> may include an operation <NUM> to compute the CPL based on an area under a curve of the PL data from the frequency start to the frequency end. The method <NUM> may include an operation <NUM> to transmit over the path by varying a desired power level of the carrier based on the CPL. The method <NUM> may include an operation <NUM> to change the path components. The method <NUM> may include an operation <NUM> to update the PL data and the CPL.

Claim 1:
A method for compensating for attenuation of carrier power by a transmission path, the method comprising;
defining (<NUM>) a path from a gateway to a measurement tap, wherein the path comprises an output port of the gateway and path components used to reach the measurement tap;
sweeping (<NUM>), in bands, an RF spectrum served by a radio frequency transmitter, RFT, by sending a signal at a respective band and a band power from the output port over the path;
measuring (<NUM>), at the measurement tap, a power metric for each of the bands;
capturing (<NUM>), for each of the bands, Power Level, PL, data comprising a frequency start of the respective band, a frequency end of the respective band, the respective band power and the respective power metric at the measurement tap; and
setting (<NUM>) a Carrier Power Level, CPL, of a carrier having a frequency start and a frequency end,
wherein the CPL is based on the PL data associated with one more of the bands included in the frequency start and the frequency end,
wherein the path components comprise one or more connecting cables, one or more switches, and one or more equipment in the path.