Ephemeris information management for satellite communication

Various aspects of the disclosure relate to managing ephemeris information. Provisions are made for providing ephemeris information to a user terminal (UT). Messages are defined for sending ephemeris information and for requesting ephemeris information. Ephemeris information for a subset of the satellites in a constellation may be sent to a UT to reduce signaling load. A UT may manage a database of ephemeris information to ensure freshness of the ephemeris information.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of India patent application number 201641005148 filed on Feb. 15, 2016, the entire content of which is incorporated herein by reference.

INTRODUCTION

Various aspects described herein relate to satellite communication and, more particularly but not exclusively, to managing ephemeris information for satellite communication.

Conventional satellite-based communication systems include gateways and one or more satellites to relay communication signals between the gateways and one or more user terminals (UTs). A gateway is an earth station having an antenna for transmitting signals to, and receiving signals from, communication satellites. A gateway provides communication links, using satellites, for connecting a UT to other UTs or users of other communication systems, such as a public switched telephone network, the Internet and various public and/or private networks. A satellite is an orbiting receiver and repeater used to relay information.

A satellite can receive signals from and transmit signals to a UT provided the UT is within the “footprint” of the satellite. The footprint of a satellite is the geographic region on the surface of the earth within the range of signals of the satellite. The footprint is usually geographically divided into “beams,” through the use of antennas (e.g., the antennas may be used to create fixed, static beams or may be used to create dynamically adjustable beams through beam-forming techniques). Each beam covers a particular geographic region within the footprint. Beams may be directed so that more than one beam from the same satellite covers the same specific geographic region. In addition, beams from multiple satellites may be directed to cover the same geographic region.

Geosynchronous satellites have long been used for communication. A geosynchronous satellite is stationary relative to a given location on the earth. However, because geosynchronous satellites are limited to a geosynchronous orbit (GSO), which is a circle having a radius of approximately 42,164 km from the center of the earth directly above the earth's equator, the number of satellites that may be placed in the GSO is limited.

As alternatives to geosynchronous satellites, communication systems which utilize a constellation of satellites in non-geosynchronous orbits, such as low-earth orbits (LEO), have been devised to provide communication coverage to the entire earth or at least large parts of the earth. In non-geosynchronous satellite-based systems, such as LEO satellite-based systems, the satellites move relative to a communication device (such as a gateway or a UT) on the ground.

SUMMARY

The following presents a simplified summary of some aspects of the disclosure to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present various concepts of some aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

In one aspect, the disclosure provides an apparatus configured for communication that includes a memory and a processor coupled to the memory. The processor and the memory are configured to: communicate a request via a satellite for satellite ephemeris information; and communicate a response to the request, wherein the response comprises satellite ephemeris information.

Another aspect of the disclosure provides a method for communication including: communicating a request via a satellite for satellite ephemeris information; and communicating a response to the request, wherein the response comprises satellite ephemeris information.

Another aspect of the disclosure provides an apparatus configured for communication. The apparatus including: first means for communicating a request via a satellite for satellite ephemeris information; and second means for communicating a response to the request, wherein the response comprises satellite ephemeris information.

Another aspect of the disclosure provides a non-transitory computer-readable medium storing computer-executable code, including code to: communicate a request via a satellite for satellite ephemeris information; and communicate a response to the request, wherein the response comprises satellite ephemeris information.

These and other aspects of the disclosure will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and implementations of the disclosure will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific implementations of the disclosure in conjunction with the accompanying figures. While features of the disclosure may be discussed relative to certain implementations and figures below, all implementations of the disclosure can include one or more of the advantageous features discussed herein. In other words, while one or more implementations may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various implementations of the disclosure discussed herein. In similar fashion, while certain implementations may be discussed below as device, system, or method implementations it should be understood that such implementations can be implemented in various devices, systems, and methods.

DETAILED DESCRIPTION

The disclosure relates in some aspects to sending ephemeris information to a user terminal (UT) via a satellite and managing the ephemeris information at the UT. A satellite network broadcasts ephemeris information to enable a UT to obtain current ephemeris information for nearby satellites. The satellite network may send ephemeris information for a subset of the satellites in a constellation to reduce signaling load. A UT can also send a request for ephemeris information to the satellite network via satellite signaling. In this case, the network may send a message (e.g., a unicast message) including the requested ephemeris information to the UT via satellite signaling. In addition, the UT may manage its own database of ephemeris information to ensure that the UT has access to current ephemeris information.

Aspects of the disclosure are described in the following description and related drawings directed to specific examples. Alternate examples may be devised without departing from the scope of the disclosure. Additionally, well-known elements will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

FIG. 1illustrates an example of a satellite communication system100which includes a plurality of satellites (although only one satellite300is shown for clarity of illustration) in non-geosynchronous orbits, for example, low-earth orbits (LEO), a satellite network portal (SNP)200(e.g., corresponding to a satellite gateway) in communication with the satellite300, a plurality of UTs400and401in communication with the satellite300, and a plurality of user equipment (UE)500and501in communication with the UTs400and401, respectively. Each UE500or501may be a user device such as a mobile device, a telephone, a smartphone, a tablet, a laptop computer, a computer, a wearable device, a smart watch, an audiovisual device, or any device including the capability to communicate with a UT. Additionally, the UE500and/or the UE501may be a device (e.g., access point, small cell, etc.) that is used to communicate to one or more end user devices. In the example illustrated inFIG. 1, the UT400and the UE500communicate with each other via a bidirectional access link (having a forward access link and a return access link), and similarly, the UT401and the UE501communicate with each other via another bidirectional access link. In another implementation, one or more additional UEs (not shown) may be configured to receive only and therefore communicate with a UT only using a forward access link. In another implementation, one or more additional UEs (not shown) may also communicate with the UT400or the UT401. Alternatively, a UT and a corresponding UE may be integral parts of a single physical device, such as a mobile telephone with an integral satellite transceiver and an antenna for communicating directly with a satellite, for example.

The SNP200may have access to the Internet108or one or more other types of public, semiprivate or private networks. In the example illustrated inFIG. 1, the SNP200is in communication with infrastructure106, which is capable of accessing the Internet108or one or more other types of public, semiprivate or private networks. The SNP200may also be coupled to various types of communication backhaul, including, for example, landline networks such as optical fiber networks or public switched telephone networks (PSTN)110. Further, in alternative implementations the SNP200may interface to the Internet108, PSTN110, or one or more other types of public, semiprivate or private networks without using the infrastructure106. Still further, the SNP200may communicate with other SNPs, such as the SNP201through the infrastructure106or alternatively may be configured to communicate to the SNP201without using the infrastructure106. The infrastructure106may include, in whole or part, a network control center (NCC), a satellite control center (SCC), a wired and/or wireless core network and/or any other components or systems used to facilitate operation of and/or communication with the satellite communication system100.

Communication between the satellite300and the SNP200in both directions are called feeder links, whereas communication between the satellite and each of the UTs400and401in both directions are called service links. A signal path from the satellite300to a ground station, which may be the SNP200or one of the UTs400and401, may be generically called a downlink. A signal path from a ground station to the satellite300may be generically called an uplink. Additionally, as illustrated, signals can have a general directionality such as a forward link and a return link (or reverse link). Accordingly, a communication link in a direction originating from the SNP200and terminating at the UT400through the satellite300is called a forward link, whereas a communication link in a direction originating from the UT400and terminating at the SNP200through the satellite300is called a return link or a reverse link. As such, the signal path from the SNP200to the satellite300is labeled a “Forward Feeder Link”112whereas the signal path from the satellite300to the SNP200is labeled a “Return Feeder Link”114inFIG. 1. In a similar manner, the signal path from each UT400or401to the satellite300is labeled a “Return Service Link”116whereas the signal path from the satellite300to each UT400or401is labeled a “Forward Service Link”118inFIG. 1.

In accordance with the teachings herein, the satellite communication system100manages ephemeris information. In some implementations, the SNP200includes a controller122that communicates ephemeris information and/or determines ephemeris information. In some implementations, the controller122receives ephemeris information and forwards the ephemeris information to the UTs. In some implementations, the controller122generates ephemeris information and forwards the ephemeris information124to the UTs. In some implementations, the UT400includes a controller126that receives and manages a local copy of ephemeris information. Other components of the satellite communication system100may include corresponding controllers as well. For example, other SNPs, satellites, and UTs (not shown) may include a corresponding controller.

FIG. 2is an example block diagram of the SNP200, which also can apply to the SNP201ofFIG. 1. The SNP200is shown to include a number of antennas205, an RF subsystem210, a digital subsystem220, a Public Switched Telephone Network (PSTN) interface230, a Local Area Network (LAN) interface240, an SNP interface245, and an SNP controller250. The RF subsystem210is coupled to the antennas205and to the digital subsystem220. The digital subsystem220is coupled to the PSTN interface230, to the LAN interface240, and to the SNP interface245. The SNP controller250is coupled to the RF subsystem210, the digital subsystem220, the PSTN interface230, the LAN interface240, and the SNP interface245.

The RF subsystem210, which may include a number of RF transceivers212, an RF controller214, and an antenna controller216, may transmit communication signals to the satellite300via a forward feeder link301F, and may receive communication signals from the satellite300via a return feeder link301R. Although not shown for simplicity, each of the RF transceivers212may include a transmit chain and a receive chain. Each receive chain may include a low noise amplifier (LNA) and a down-converter (e.g., a mixer) to amplify and down-convert, respectively, received communication signals in a well-known manner. In addition, each receive chain may include an analog-to-digital converter (ADC) to convert the received communication signals from analog signals to digital signals (e.g., for processing by the digital subsystem220). Each transmit chain may include an up-converter (e.g., a mixer) and a power amplifier (PA) to up-convert and amplify, respectively, communication signals to be transmitted to the satellite300in a well-known manner. In addition, each transmit chain may include a digital-to-analog converter (DAC) to convert the digital signals received from the digital subsystem220to analog signals to be transmitted to the satellite300.

The RF controller214may be used to control various aspects of a number of RF transceivers212(e.g., selection of the carrier frequency, frequency and phase calibration, gain settings, and the like). The antenna controller216may control various aspects of the antennas205(e.g., beamforming, beam steering, gain settings, frequency tuning, and the like).

The digital subsystem220may include a number of digital receiver modules222, a number of digital transmitter modules224, a baseband (BB) processor226, and a control (CTRL) processor228. The digital subsystem220may process communication signals received from the RF subsystem210and forward the processed communication signals to the PSTN interface230and/or the LAN interface240, and may process communication signals received from the PSTN interface230and/or the LAN interface240and forward the processed communication signals to the RF subsystem210.

Each digital receiver module222may correspond to signal processing elements used to manage communication between the SNP200and the UT400. One of the receive chains of RF transceivers212may provide input signals to multiple digital receiver modules222. A number of digital receiver modules222may be used to accommodate all of the satellite beams and possible diversity mode signals being handled at any given time. Although not shown for simplicity, each digital receiver module222may include one or more digital data receivers, a searcher receiver, and a diversity combiner and decoder circuit. The searcher receiver may be used to search for appropriate diversity modes of carrier signals, and may be used to search for pilot signals (or other relatively fixed pattern strong signals).

The digital transmitter modules224may process signals to be transmitted to the UT400via the satellite300. Although not shown for simplicity, each digital transmitter module224may include a transmit modulator that modulates data for transmission. The transmission power of each transmit modulator may be controlled by a corresponding digital transmit power controller (not shown for simplicity) that may (1) apply a minimum level of power for purposes of interference reduction and resource allocation and (2) apply appropriate levels of power when needed to compensate for attenuation in the transmission path and other path transfer characteristics.

The control processor228, which is coupled to the digital receiver modules222, the digital transmitter modules224, and the baseband processor226, may provide command and control signals to effect functions such as, but not limited to, signal processing, timing signal generation, power control, handoff control, diversity combining, and system interfacing.

The control processor228may also control the generation and power of pilot, synchronization, and paging channel signals and their coupling to the transmit power controller (not shown for simplicity). The pilot channel is a signal that is not modulated by data, and may use a repetitive unchanging pattern or non-varying frame structure type (pattern) or tone type input. For example, the orthogonal function used to form the channel for the pilot signal generally has a constant value, such as all 1's or 0's, or a well-known repetitive pattern, such as a structured pattern of interspersed 1's and 0's.

The baseband processor226is well known in the art and is therefore not described in detail herein. For example, the baseband processor226may include a variety of known elements such as (but not limited to) coders, data modems, and digital data switching and storage components.

The PSTN interface230may provide communication signals to, and receive communication signals from, an external PSTN either directly or through additional infrastructure106, as illustrated inFIG. 1. The PSTN interface230is well known in the art, and therefore is not described in detail herein. For other implementations, the PSTN interface230may be omitted, or may be replaced with any other suitable interface that connects the SNP200to a ground-based network (e.g., the Internet).

The LAN interface240may provide communication signals to, and receive communication signals from, an external LAN. For example, the LAN interface240may be coupled to the Internet108either directly or through additional infrastructure106, as illustrated inFIG. 1. The LAN interface240is well known in the art, and therefore is not described in detail herein.

The SNP interface245may provide communication signals to, and receive communication signals from, one or more other SNPs associated with the satellite communication system100ofFIG. 1(and/or to/from SNPs associated with other satellite communication systems, not shown for simplicity). For some implementations, the SNP interface245may communicate with other SNPs via one or more dedicated communication lines or channels (not shown for simplicity). For other implementations, the SNP interface245may communicate with other SNPs using the PSTN110and/or other networks such as the Internet108(see alsoFIG. 1). For at least one implementation, the SNP interface245may communicate with other SNPs via the infrastructure106.

Overall SNP control may be provided by the SNP controller250. The SNP controller250may plan and control utilization of the satellite300's resources by the SNP200. For example, the SNP controller250may analyze trends, generate traffic plans, allocate satellite resources, monitor (or track) satellite positions, and monitor the performance of the SNP200and/or the satellite300. The SNP controller250may also be coupled to a ground-based satellite controller (not shown for simplicity) that maintains and monitors orbits of the satellite300, relays satellite usage information to the SNP200, tracks the positions of the satellite300, and/or adjusts various channel settings of the satellite300.

For the example implementation illustrated inFIG. 2, the SNP controller250includes local time, frequency, and position references251, which may provide local time or frequency information to the RF subsystem210, the digital subsystem220, and/or the interfaces230,240, and245. The time or frequency information may be used to synchronize the various components of the SNP200with each other and/or with the satellite(s)300. The local time, frequency, and position references251may also provide position information (e.g., ephemeris data) of the satellite(s)300to the various components of the SNP200. Further, although depicted inFIG. 2as included within the SNP controller250, for other implementations, the local time, frequency, and the position references251may be a separate subsystem that is coupled to the SNP controller250(and/or to one or more of the digital subsystem220and the RF subsystem210).

Although not shown inFIG. 2for simplicity, the SNP controller250may also be coupled to a network control center (NCC) and/or a satellite control center (SCC). For example, the SNP controller250may allow the SCC to communicate directly with the satellite(s)300, for example, to retrieve ephemeris data from the satellite(s)300. The SNP controller250may also receive processed information (e.g., from the SCC and/or the NCC) that allows the SNP controller250to properly aim its antennas205(e.g., at the appropriate satellite(s)300), to schedule beam transmissions, to coordinate handoffs, and to perform various other well-known functions.

The SNP controller250may include one or more of a processing circuit232, a memory device234, or an ephemeris controller236that independently or cooperatively perform ephemeris information-related operations for the SNP200as taught herein. In an example implementation, the processing circuit232is configured (e.g., programmed) to perform some or all of these operations. In another example implementation, the processing circuit232(e.g., in the form of a processor) executes code stored in the memory device234to perform some or all of these operations. In another example implementation, the ephemeris controller236is configured (e.g., programmed) to perform some or all of these operations. Although depicted inFIG. 2as included within the SNP controller250, for other implementations, one or more of the processing circuit232, the memory device234, or the ephemeris controller236may be a separate subsystem that is coupled to the SNP controller250(and/or to one or more of the digital subsystem220and the RF subsystem210).

FIG. 3is an example block diagram of the satellite300for illustrative purposes only. It will be appreciated that specific satellite configurations can vary significantly and may or may not include on-board processing. Further, although illustrated as a single satellite, two or more satellites using inter-satellite communication may provide the functional connection between the SNP200and the UT400. It will be appreciated that the disclosure is not limited to any specific satellite configuration and any satellite or combinations of satellites that can provide the functional connection between the SNP200and UT400can be considered within the scope of the disclosure. In one example, the satellite300is shown to include a forward transponder310, a return transponder320, an oscillator330, a controller340, forward link antennas351and352(1)-352(N), and return link antennas362and361(1)-361(N). The forward transponder310, which may process communication signals within a corresponding channel or frequency band, may include a respective one of first bandpass filters311(1)-311(N), a respective one of first low noise amplifiers (LNAs)312(1)-312(N), a respective one of frequency converters313(1)-313(N), a respective one of second LNAs314(1)-314(N), a respective one of second bandpass filters315(1)-315(N), and a respective one of power amplifiers (PAs)316(1)-316(N). Each of the PAs316(1)-316(N) is coupled to a respective one of antennas352(1)-352(N), as shown inFIG. 3.

Within each of respective forward paths FP(1)-FP(N), the first bandpass filter311passes signal components having frequencies within the channel or frequency band of the respective forward path FP, and filters signal components having frequencies outside the channel or frequency band of the respective forward path FP. Thus, the pass band of the first bandpass filter311corresponds to the width of the channel associated with the respective forward path FP. The first LNA312amplifies the received communication signals to a level suitable for processing by the frequency converter313. The frequency converter313converts the frequency of the communication signals in the respective forward path FP (e.g., to a frequency suitable for transmission from the satellite300to the UT400). The second LNA314amplifies the frequency-converted communication signals, and the second bandpass filter315filters signal components having frequencies outside of the associated channel width. The PA316amplifies the filtered signals to a power level suitable for transmission to the UTs400via a respective antenna352. The return transponder320, which includes a number N of return paths RP(1)-RP(N), receives communication signals from the UT400along the return service link302R via the antennas361(1)-361(N), and transmits communication signals to the SNP200along the return feeder link301R via one or more of the antennas362. Each of the return paths RP(1)-RP(N), which may process communication signals within a corresponding channel or frequency band, may be coupled to a respective one of the antennas361(1)-361(N), and may include a respective one of first bandpass filters321(1)-321(N), a respective one of first LNAs322(1)-322(N), a respective one of frequency converters323(1)-323(N), a respective one of second LNAs324(1)-324(N), and a respective one of second bandpass filters325(1)-325(N).

Within each of the respective return paths RP(1)-RP(N), the first bandpass filter321passes signal components having frequencies within the channel or frequency band of the respective return path RP, and filters signal components having frequencies outside the channel or frequency band of the respective return path RP. Thus, the pass band of the first bandpass filter321may for some implementations correspond to the width of the channel associated with the respective return path RP. The first LNA322amplifies all the received communication signals to a level suitable for processing by the frequency converter323. The frequency converter323converts the frequency of the communication signals in the respective return path RP (e.g., to a frequency suitable for transmission from the satellite300to the SNP200). The second LNA324amplifies the frequency-converted communication signals, and the second bandpass filter325filters signal components having frequencies outside of the associated channel width. Signals from the return paths RP(1)-RP(N) are combined and provided to the one or more antennas362via a PA326. The PA326amplifies the combined signals for transmission to the SNP200.

The oscillator330, which may be any suitable circuit or device that generates an oscillating signal, provides a forward local oscillator signal LO(F) to the frequency converters313(1)-313(N) of the forward transponder310, and provides a return local oscillator signal LO(R) to the frequency converters323(1)-323(N) of the return transponder320. For example, the LO(F) signal may be used by the frequency converters313(1)-313(N) to convert communication signals from a frequency band associated with the transmission of signals from the SNP200to the satellite300to a frequency band associated with the transmission of signals from the satellite300to the UT400. The LO(R) signal may be used by the frequency converters323(1)-323(N) to convert communication signals from a frequency band associated with the transmission of signals from the UT400to the satellite300to a frequency band associated with the transmission of signals from the satellite300to the SNP200.

The controller340, which is coupled to the forward transponder310, the return transponder320, and the oscillator330, may control various operations of the satellite300including (but not limited to) channel allocations. In one aspect, the controller340may include a processing circuit364(e.g., a processor) coupled to a memory (e.g., a memory device366). The memory may include a non-transitory computer-readable medium (e.g., one or more nonvolatile memory elements, such as an EPROM, an EEPROM, a Flash memory, a hard drive, etc.) storing instructions that, when executed by the processing circuit364, cause the satellite300to perform operations including (but not limited to) those described herein.

An example of a transceiver for use in the UT400or the UT401is illustrated inFIG. 4. InFIG. 4, at least one antenna410is provided for receiving forward link communication signals (e.g., from the satellite300), which are transferred to an analog receiver414, where they are down-converted, amplified, and digitized. A duplexer element412is often used to allow the same antenna to serve both transmit and receive functions. Alternatively, a UT transceiver may employ separate antennas for operating at different transmit and receive frequencies.

The digital communication signals output by the analog receiver414are transferred to at least one digital data receiver416A and at least one searcher receiver418. Additional digital data receivers (e.g., as represented by a digital data receiver416N) can be used to obtain desired levels of signal diversity, depending on the acceptable level of transceiver complexity, as would be apparent to one skilled in the relevant art.

At least one user terminal control processor420is coupled to the digital data receivers416A-416N and the searcher receiver418. The control processor420provides, among other functions, basic signal processing, timing, power and handoff control or coordination, and selection of frequency used for signal carriers. Another basic control function that may be performed by the control processor420is the selection or manipulation of functions to be used for processing various signal waveforms. Signal processing by the control processor420can include a determination of relative signal strength and computation of various related signal parameters. Such computations of signal parameters, such as timing and frequency may include the use of additional or separate dedicated circuitry to provide increased efficiency or speed in measurements or improved allocation of control processing resources.

The outputs of the digital data receivers416A-416N are coupled to digital baseband circuitry422within the UT400. The digital baseband circuitry422includes processing and presentation elements used to transfer information to and from the UE500as shown inFIG. 1, for example. Referring toFIG. 4, if diversity signal processing is employed, the digital baseband circuitry422may include a diversity combiner and decoder (not shown). Some of these elements may also operate under the control of, or in communication with, a control processor420.

When voice or other data is prepared as an output message or a communication signal originating with the UT400, the digital baseband circuitry422is used to receive, store, process, and otherwise prepare the desired data for transmission. The digital baseband circuitry422provides this data to a transmit modulator426operating under the control of the control processor420. The output of the transmit modulator426is transferred to a power controller428which provides output power control to a transmit power amplifier430for final transmission of the output signal from the antenna410to a satellite (e.g., the satellite300).

InFIG. 4, the UT transceiver also includes a memory432associated with the control processor420. The memory432may include instructions for execution by the control processor420as well as data for processing by the control processor420. In the example illustrated inFIG. 4, the memory432may include instructions for performing time or frequency adjustments to be applied to an RF signal to be transmitted by the UT400via the return service link to the satellite300.

In the example illustrated inFIG. 4, the UT400also includes optional local time, frequency and/or position references434(e.g., a GPS receiver), which may provide local time, frequency and/or position information to the control processor420for various applications, including, for example, time or frequency synchronization for the UT400.

The digital data receivers416A-416N and the searcher receiver418are configured with signal correlation elements to demodulate and track specific signals. The searcher receiver418is used to search for pilot signals, or other relatively fixed pattern strong signals, while the digital data receivers416A-416N are used to demodulate other signals associated with detected pilot signals. However, a digital data receiver416can be assigned to track the pilot signal after acquisition to accurately determine the ratio of signal chip energies to signal noise, and to formulate pilot signal strength. Therefore, the outputs of these units can be monitored to determine the energy in, or frequency of, the pilot signal or other signals. These receivers also employ frequency tracking elements that can be monitored to provide current frequency and timing information to the control processor420for signals being demodulated.

The control processor420may use such information to determine to what extent the received signals are offset from the oscillator frequency, when scaled to the same frequency band, as appropriate. This and other information related to frequency errors and frequency shifts can be stored in a storage or memory element (e.g., the memory432) as desired.

The control processor420may also be coupled to the UE interface circuitry450to allow communication between the UT400and one or more UEs. The UE interface circuitry450may be configured as desired for communication with various UE configurations and accordingly may include various transceivers and related components depending on the various communication technologies employed to communicate with the various UEs supported. For example, the UE interface circuitry450may include one or more antennas, a wide area network (WAN) transceiver, a wireless local area network (WLAN) transceiver, a Local Area Network (LAN) interface, a Public Switched Telephone Network (PSTN) interface and/or other known communication technologies configured to communicate with one or more UEs in communication with the UT400.

The control processor420may include one or more of a processing circuit442, a memory device444, or an ephemeris controller446that independently or cooperatively perform ephemeris information-related operations for the UT400as taught herein. In an example implementation, the processing circuit442is configured (e.g., programmed) to perform some or all of these operations. In another example implementation, the processing circuit442(e.g., in the form of a processor) executes code stored in the memory device444to perform some or all of these operations. In another example implementation, the ephemeris controller446is configured (e.g., programmed) to perform some or all of these operations. Although depicted inFIG. 4as included within the control processor420, for other implementations, one or more of the processing circuit442, the memory device444, or the ephemeris controller446may be a separate subsystem that is coupled to the control processor420.

FIG. 5is a block diagram illustrating an example of the UE500, which also can apply to the UE501ofFIG. 1. The UE500as shown inFIG. 5may be a mobile device, a handheld computer, a tablet, a wearable device, a smart watch, or any type of device capable of interacting with a user, for example. Additionally, the UE500may be a network side device that provides connectivity to various ultimate end user devices and/or to various public or private networks. In the example shown inFIG. 5, the UE500may include a LAN interface502, one or more antennas504, a wide area network (WAN) transceiver506, a wireless local area network (WLAN) transceiver508, and a satellite positioning system (SPS) receiver510. The SPS receiver510may be compatible with the Global Positioning System (GPS), the Global Navigation Satellite System (GLONASS) and/or any other global or regional satellite based positioning system. In an alternate aspect, the UE500may include a WLAN transceiver508, such as a Wi-Fi transceiver, with or without the LAN interface502, the WAN transceiver506, and/or the SPS receiver510, for example. Further, the UE500may include additional transceivers such as Bluetooth, ZigBee and other known technologies, with or without the LAN interface502, the WAN transceiver506, the WLAN transceiver508and/or the SPS receiver510. Accordingly, the elements illustrated for the UE500are provided merely as an example configuration and are not intended to limit the configuration of UEs in accordance with the various aspects disclosed herein.

In the example shown inFIG. 5, a processor512is connected to the LAN interface502, the WAN transceiver506, the WLAN transceiver508and the SPS receiver510. Optionally, a motion sensor514and other sensors may also be coupled to the processor512.

A memory516is connected to the processor512. In one aspect, the memory516may include data518which may be transmitted to and/or received from the UT400, as shown inFIG. 1. Referring toFIG. 5, the memory516may also include stored instructions520to be executed by the processor512to perform the process steps for communicating with the UT400, for example. Furthermore, the UE500may also include a user interface522, which may include hardware and software for interfacing inputs or outputs of the processor512with the user through light, sound or tactile inputs or outputs, for example. In the example shown inFIG. 5, the UE500includes a microphone/speaker524, a keypad526, and a display528connected to the user interface522. Alternatively, the user's tactile input or output may be integrated with the display528by using a touch-screen display, for example. Once again, the elements illustrated inFIG. 5are not intended to limit the configuration of the UEs disclosed herein and it will be appreciated that the elements included in the UE500will vary based on the end use of the device and the design choices of the system engineers.

Additionally, the UE500may be a user device such as a mobile device or external network side device in communication with but separate from the UT400as illustrated inFIG. 1, for example. Alternatively, the UE500and the UT400may be integral parts of a single physical device.

In the example shown inFIG. 1, the two UTs400and401may conduct two-way communication with the satellite300via return and forward service links within a beam coverage. A satellite may communicate with more than two UTs within a beam coverage. The return service link from the UTs400and401to the satellite300may thus be a many-to-one channel. Some of the UTs may be mobile while others may be stationary, for example. In a satellite communication system such as the example illustrated inFIG. 1, multiple UTs400and401within a beam coverage may be time-division-multiplexed (TDM'ed), frequency-division-multiplexed (FDM'ed), or both.

At some point in time, a UT may need to be handed-off to another satellite (not shown inFIG. 1). Handoff may be caused by scheduled events or unscheduled events.

Several examples of handoff due to scheduled events follow. Inter-beam and inter-satellite handoff may be caused by movement of the satellite, movement of the UT, or a satellite beam being turned off (e.g., due to a Geo-stationary satellite (GEO) restriction). Handoff also may be due to a satellite moving out of the SNP's range while the satellite is still within the UT's line of sight.

Several examples of handoff due to nonscheduled events follow. Handoff may be triggered by a satellite being obscured by an obstacle (e.g., a tree). Handoff also may be triggered due to a drop in channel quality (e.g., signal quality) due to rain fade or other atmospheric conditions.

In some implementations, at a particular point in time, a particular satellite may be controlled by a particular entity (e.g., a network access controller, NAC) in an SNP. Thus, an SNP may have several NACs (e.g., implemented by the SNP controller250ofFIG. 2), each of which controls a corresponding one of the satellites controlled by the SNP. In addition, a given satellite may support multiple beams. Thus, over time, different types of handoff may occur.

In inter-beam handoff, a UT is handed-off from one beam of a satellite to another beam of the satellite. For example, the particular beam serving a stationary UT may change over time as the serving satellite moves.

In inter-satellite handoff, a UT is handed-off from the current serving satellite (referred to as the source satellite) to another satellite (referred to as the target satellite). For example, a UT may be handed-off to the target satellite as the source satellite moves away from the UT and the target satellite moves toward the UT.

Ephemeris Information

In an example non-geosynchronous satellite communication system implementation, satellites move over the earth in ascending or descending paths (e.g., approximately a north-south or south-north direction). The rotation of the earth causes an apparent motion in east-west direction. Each UT obtains the expected path of the satellites (satellite ephemeris information) that the UT is going to see for some prescribed period of time in the future so that it can establish radio connections to the satellites. In some aspects, the UT can receive this satellite ephemeris information via a broadcast message and/or a unicast message from the network (e.g., from an SNP). In some aspects, the UT can request this satellite ephemeris information if it is not available and has not been provided to it by the network in reasonable time. The disclosed implementation works at all longitude and latitude values, including satellite constellation designs where satellites in adjacent planes are moving in opposite directions. The disclosed implementation also provides for unambiguous storage of the satellite ephemeris information and discard of this information if it becomes stale.

FIG. 6illustrates a UT602in communication with an SNP604via a satellite606in a non-geosynchronous satellite communication system600, such as a LEO satellite communication system for data, voice, video, or other communication. The UT602, the SNP604, and the satellite606may respectively correspond to, for example, the UT400, the SNP200, and the satellite300ofFIG. 1.

The SNP604includes network access controllers (NACs)612, each of which interfaces with one or more radio frequency (RF) subsystems614for communicating with the UT602and other UTs (not shown) via the satellite606(or some other satellite, not shown). The SNP604also includes a core network control plane (CNCP)616and a core network user plane (CNUP)618, or other similar functionality, for communicating with another network620. The network620may represent, for example, one or more of a core network (e.g., 3G, 4G, 5G, etc.), an intranet, or the Internet.

The SNP604may determine (e.g., receive or generate) ephemeris information622. The SNP may then broadcast or unicast the ephemeris information622to the UT602via messages624and626relayed by the satellite606. The UT602thereby maintains its own ephemeris information628.

Ephemeris Messages

An SNP may broadcast to all of its UTs a Broadcast Information Block (BIB) message that includes ephemeris information. For examples, BIB messages may be broadcast on an overhead (or common channel). Example BIB structures702and704are shown inFIG. 7. In these examples, the BIB structure702corresponds to a location near the equator, while the BIB structure702corresponds to a location near the poles. Each BIB structure includes a first BIB element, referred to as BIB1, that includes information regarding a schedule (e.g., periodicity) of another BIB element, referred to as BIBe, that includes the ephemeris information for a set of satellites.

In an example implementation, the value tag included in the BIB1does not change for any updates to the BIBe. One proposed periodicity of the BIBe is 512 frames (e.g., 5.12 seconds). In this case, the BIB1indicates that the BIBe will be sent every 512 frames. Other values may be used.

The “refresh period” indicates the time duration within which the UT must perform another reading of the BIBe. If the value of the “refresh period” is set to 6 minutes, the UT will attempt to read the BIBe once every 6 minutes. If the value of the “refresh period” is set to 0, the UT will keep attempting to read the BIBe (e.g., every time the BIBe is broadcast by the SNP).

Within a given “refresh period,” a UT will “see” (e.g., receive signals from) a subset of the broadcast satellites—the UT will not “see” any other satellites within the “refresh period.” The BIBe includes, at least, all the satellites that any UT under its footprint may “see” within the next “refresh period” duration.

Therefore, the number of satellites included in the BIBe may be a function of the “refresh period.” For example, if a larger number of satellites are listed in the BIBe, a longer “refresh period” may be specified.

The number of satellites included in the BIBe may be a function of the local latitude. For example, satellite paths may converge at northern latitudes and southern latitudes. Therefore, to cover a UT for a given period of time (e.g., 6 minutes) at these latitudes, more satellites may be listed in the BIBe for these latitudes than in a BIBe for a central latitude (e.g., a latitude closer to the equator).

Relatively small ephemeris information messages may be sent (e.g., due to the use of fewer satellite entries, fewer ephemeris elements, smaller ephemeris elements, or less strict accuracy requirements). In some implementations, an ephemeris information message may be at most three bytes per term (e.g., ephemeris information element). In some implementations, an ephemeris information message may be at most two bytes per term (e.g., ephemeris information element).

Examples of ephemeris messages include a Radio Ephemeris Information Request message and a Radio Ephemeris Information message. Each of these messages will be discussed in turn.

A Radio Ephemeris Information Request message is used by the UT for requesting the ephemeris information in a unicast manner A UT may send such a request, for example, if the UT determines that it will not be able to receive the ephemeris information via broadcasts messages before expiration of the “refresh period.”

The request could be for the ephemeris information for the full constellation (e.g., 600-1000 satellites) or the request could be for only a part of the constellation (e.g., consisting of those satellites that will be seen in the next few minutes). A “request type” bit in the message may indicate the type of request. A request for the ephemeris information for the full constellation will cause the SNP to provide all of this information.

A Radio Ephemeris Information message is the response message containing the ephemeris information. In some implementations, the format of the information in this unicast message is the same as that included in an ephemeris information broadcast message (e.g., that includes the BIBe). In some implementations, the format of the information in this unicast message is different from that included in an ephemeris information broadcast message. The response may contain the ephemeris information for the full constellation or only a part of it, as requested by the UT. As with BIBs, the number of satellites included in this message may be a function of the included “refresh period” as well as the local latitude.

Ephemeris Elements

In an example implementation, the ephemeris information for one satellite consists of the eight elements that follow. Other sets of information and/or other field lengths may be used in other implementations.

Satellite Identifier Number (Id) uniquely identifies a satellite within the system. The length of this field may be 16 bits. This field may be over-provisioned to allow for any unanticipated growth in the number of satellites.

Epoch Time (T0) indicates the predictive fit-time for the satellite. It is the GPS time in seconds with t0set to 00:00:00 on 1 Jan. 1980. The length of this field may be 32 bits and its rollover may happen in 2116.

Semi-Major Axis (a) indicates the length of the semi-major axis of the elliptical path of the satellite in meters. The length of this field may be 24 bits.

Eccentricity (e) indicates the eccentricity of the elliptical path of the satellite. The length of this field may be 24 bits. This element may have a precision of 1.00E-07.

Argument of Perigee (w) indicates the argument of the perigee of the path of the satellite. The length of this field may be 24 bits. This element may have a precision of 0.0000214576 degrees.

Inclination (i) indicates the inclination of the path of the satellite. The length of this field may be 24 bits. This element may have a precision of 0.0000053644 degrees.

Right Ascension of Ascending Node (Ω or Omega) indicates the right ascension of the ascending node. The length of this field may be 24 bits. This element may have a precision of 0.0000214576 degrees.

Mean Anomaly at Epoch (M0) indicates the mean anomaly at the epoch time. The length of this field may be 24 bits. This element may have a precision of 0.0000214576 degrees. Table 1 summarizes one example of the above ephemeris elements.

A UT may calculate other ephemeris elements based on received ephemeris information. For example, a UT may calculate rate terms that are associated with received inclination, angle information (e.g., precession rate of right ascension node to the west), or other time dependent secular and periodic changes to ephemeris elements.

Satellite List

In an example implementation, the footprint of a satellite completely crosses over a point on earth in the north-south direction in about 3 minutes at all latitudes. In addition, the satellite planes appear to move by a maximum of ˜85 km (at equator) in those 3 minutes due to the rotational motion of earth.FIGS. 8-11illustrate several examples of satellite footprints in different scenarios. To simply the complexity of the figures, the footprint of a satellite at a given point in time is simply represented by a square (e.g., numbered as 1, 2, 3, etc., in the figures).

FIG. 8illustrates a set of footprints800where all the static (stationary) UTs located within the footprint of the current satellite will be effectively located somewhere within the shaded region802in the next 3 minutes. Thus, the ephemeris information provided to the UTs should be valid over this period of time (corresponding to the region802, including the current footprint). Other time frames may be applicable in other implementations.

The current footprint inFIG. 8represents the area where a given overhead message (e.g., a message including the BIBe) will be received by UTs. The portion of the shaded region802to the right of the first and second footprints (i.e., in the left hand side of the footprints 3, 4, and 5) is due to the rotation of the earth (from west to east) below the satellites. Thus, the constellation slides from east to west.

Satellites in adjacent planes may be offset in phase (the phase offset of ascending nodes in those adjacent planes). In the examples illustrated inFIGS. 8, 9, 10, and 11, an offset of 5° has been assumed. Although the actual phase offset may differ operationally from the 5° shown, the number of satellites visible within the temporal window examined in these examples need not change with the choice of the offset.

A moving UT (e.g., a UT on-board an aircraft) may also change its position in those 3 minutes. Therefore, the satellites that a UT may “see” within the next 3 minutes include the following: 1) the current satellite; 2) the next two satellites in the same plane; and, 3) the neighbouring satellites (in the two adjacent planes) of the above three satellites.

Since there is an offset between the satellite positions in the neighbouring planes, there are two neighbours of a satellite on either side. This makes the total number of satellites equal to 9.

Referring now to the set of footprints900inFIG. 9, the shaded areas902indicate the possible locations for the UTs in the footprint of the current satellite in the next 3 minutes.

The shaded areas904indicate the locations where a UT in the footprint of the current satellite would not reach (e.g., because the satellite's footprint moves much faster than a UT).

The above examples can be extended to, for example, 6 minutes of coverage. In this case the number of satellites may be 12, as shown in the set of footprints1000inFIG. 10. In practice, ephemeris information for the satellites indicated forFIG. 9orFIG. 10would typically be broadcast since this covers either static or moving UTs. In this case, ephemeris information for the satellites indicated forFIG. 8for static UTs could still be unicast (e.g., to reduce the signaling overhead).

The geographical width of a plane reduces towards the poles and therefore the number of visible satellites increases with altitude as mentioned above. Appropriate examples can be constructed for those scenarios based on the principles discussed herein.

Broadcast Overhead

Assuming a “refresh time” of 6 minutes, the number of satellites included in the ephemeris information may be 12 near the equator. This amounts to, for example, 12*24=288 bytes.

The number of Airlink Resource Units (e.g., comprising time units and/or frequency units) required to carry this information at −10 dB SNR may be 173, effectively resulting in an overhead of approximately 34 Airlink Resource Units per second (0.003%) assuming a periodicity of 5.12 seconds.

At near 60° latitude, this number could go up to 24 satellites, amounting to 576 bytes and requiring 343 Airlink Resource Units per second (an overhead of 0.006%) as one example.

Operation Near the Seams

A “seam” is a location where the motions of the satellites in two neighbouring planes are in the opposite directions, i.e., where the north-bound and south-bound satellites are next to each other. In an example implementation, there may be two seams in the system.

The satellites to be included near the “seams” may be a mirror image of those that would have been included had the motion of the ‘different’ plane also been in the same direction.

FIG. 11illustrates an example of set of footprints1100of the satellites to be included in the ephemeris information list for the operation near the seams. The shaded area1102indicate the possible locations for the UTs in the footprint of the current satellite in the next 6 minutes.

Example Parameters

The length of the Satellite List (in the BIB) may be 1 . . . 256 in an example implementation. The proposed value for the initial system setup may be 12, worth 6 minutes near equator. At the maximum capacity of 256 satellites a “refresh period” of about 250 minutes can be attained near the equator (approximately 125 minutes near 60° latitude). The length of the Satellite List in the unicast message “Radio Ephemeris Information” may be 1 . . . 4096.

The range for the BIBe Refresh Time (in the BIB) may be {30*(0 . . . 255) seconds)}. An example value for the initial setup is 12 (i.e., 360 seconds or 6 minutes). In some implementations, it may be assumed that it is neither necessary nor desirable to broadcast the ephemeris information for a larger “refresh time.” The range for the BIBe Refresh Time in the unicast message “Radio Ephemeris Information” may also be the same.

Reception Operation

When the UT receives the ephemeris information in the BIBe or in the Radio Ephemeris Information message, the UT starts a timer with a duration equal to the indicated “refresh period,” and the next BIBe reading is completed before the timer expires. If the value of the “refresh period” is set to 0, the UT keeps attempting to read the BIBe at the next scheduled occasions (e.g., frames) indicated by the BIB1. If it becomes known to the UT that the BIBe reading cannot be completed within the “refresh period”, the UT requests the SNP for unicast transfer of the ephemeris information by sending a “Radio Ephemeris Information Request” message.

The UT can request the SNP for the ephemeris information in the “Radio Ephemeris Information Request” message, when needed. This could be needed due to, for example, half-duplex operation of connected mode UTs (e.g., a half-duplex UT may be unable to receive a broadcast or unicast message when the UT is transmitting) or any other unforeseen reason. A recently powered-on UT may request the SNP for the transfer of ephemeris information for the full constellation.

The SNP can, on its own, unicast the ephemeris information in the “Radio Ephemeris Information” message, when needed. One possible reason for the SNP unilaterally unicasting this information could be to proactively transfer the ephemeris information to those connected UTs that are going to be actively transmitting for some time. This could also be done due to any unforeseen reason. This unilateral unicasting may be a backup mechanism in some implementations.

Storage Operation

The UT may maintain a database of ephemeris information for all satellites, indexed by their satellite identities.

When the UT receives the ephemeris information for a satellite, if an entry is not present for that satellite in the database, the UT may create an entry in its database and store the received information for that satellite there. If the ephemeris information for that satellite is already stored in the database, the UT may overwrite that existing information with the received information.

The UT may keep the ephemeris information for a satellite stored in its database for a minimum period of time (e.g., due to a failed satellite) unless it is overwritten with freshly received ephemeris information. In some implementations, the minimum period of time is 15 days. Other periods of time could be used in other implementations.

If the UT receives the ephemeris information for the full constellation, the UT may discard its complete existing ephemeris database and replace it with the received information.

A UT may obtain ephemeris information in other ways. As one example, ephemeris information could be loaded into the UT (e.g., using a thumb-drive, via the Internet, via a software update, etc.).

First Example Apparatus

FIG. 12illustrates a block diagram of an example hardware implementation of an apparatus1200configured to communicate according to one or more aspects of the disclosure. For example, the apparatus1200could embody or be implemented within an SNP, or some other type of device that supports satellite communication. In various implementations, the apparatus1200could embody or be implemented within a gateway, a ground station, a vehicular component, or any other electronic device having circuitry.

The apparatus1200includes a communication interface (e.g., at least one transceiver)1202, a storage medium1204, a user interface1206, a memory device (e.g., a memory circuit)1208, and a processing circuit (e.g., at least one processor)1210. In various implementations, the user interface1206may include one or more of: a keypad, a display, a speaker, a microphone, a touchscreen display, of some other circuitry for receiving an input from or sending an output to a user.

These components can be coupled to and/or placed in electrical communication with one another via a signaling bus or other suitable component, represented generally by the connection lines inFIG. 12. The signaling bus may include any number of interconnecting buses and bridges depending on the specific application of the processing circuit1210and the overall design constraints. The signaling bus links together various circuits such that each of the communication interface1202, the storage medium1204, the user interface1206, and the memory device1208are coupled to and/or in electrical communication with the processing circuit1210. The signaling bus may also link various other circuits (not shown) such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The communication interface1202provides a means for communicating with other apparatuses over a transmission medium. In some implementations, the communication interface1202includes circuitry and/or programming adapted to facilitate the communication of information bi-directionally with respect to one or more communication devices in a network. In some implementations, the communication interface1202is adapted to facilitate wireless communication of the apparatus1200. In these implementations, the communication interface1202may be coupled to one or more antennas1212as shown inFIG. 12for wireless communication within a wireless communication system. The communication interface1202can be configured with one or more standalone receivers and/or transmitters, as well as one or more transceivers. In the illustrated example, the communication interface1202includes a transmitter1214and a receiver1216. The communication interface1202serves as one example of a means for receiving and/or means transmitting.

The memory device1208may represent one or more memory devices. As indicated, the memory device1208may maintain ephemeris information1218along with other information used by the apparatus1200. In some implementations, the memory device1208and the storage medium1204are implemented as a common memory component. The memory device1208may also be used for storing data that is manipulated by the processing circuit1210or some other component of the apparatus1200.

The storage medium1204may represent one or more computer-readable, machine-readable, and/or processor-readable devices for storing programming, such as processor executable code or instructions (e.g., software, firmware), electronic data, databases, or other digital information. The storage medium1204may also be used for storing data that is manipulated by the processing circuit1210when executing programming. The storage medium1204may be any available media that can be accessed by a general purpose or special purpose processor, including portable or fixed storage devices, optical storage devices, and various other mediums capable of storing, containing or carrying programming.

By way of example and not limitation, the storage medium1204may include a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD)), a smart card, a flash memory device (e.g., a card, a stick, or a key drive), a random access memory (RAM), a read only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The storage medium1204may be embodied in an article of manufacture (e.g., a computer program product). By way of example, a computer program product may include a computer-readable medium in packaging materials. In view of the above, in some implementations, the storage medium1204may be a non-transitory (e.g., tangible) storage medium.

The storage medium1204may be coupled to the processing circuit1210such that the processing circuit1210can read information from, and write information to, the storage medium1204. That is, the storage medium1204can be coupled to the processing circuit1210so that the storage medium1204is at least accessible by the processing circuit1210, including examples where at least one storage medium is integral to the processing circuit1210and/or examples where at least one storage medium is separate from the processing circuit1210(e.g., resident in the apparatus1200, external to the apparatus1200, distributed across multiple entities, etc.).

Programming stored on the storage medium1204, when executed by the processing circuit1210, causes the processing circuit1210to perform one or more of the various functions and/or process operations described herein. For example, the storage medium1204may include operations configured for regulating operations at one or more hardware blocks of the processing circuit1210, as well as to utilize the communication interface1202for wireless communication utilizing their respective communication protocols.

The processing circuit1210is generally adapted for processing, including the execution of such programming stored on the storage medium1204. As used herein, the terms “code” or “programming” shall be construed broadly to include without limitation instructions, instruction sets, data, code, code segments, program code, programs, programming, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

The processing circuit1210is arranged to obtain, process and/or send data, control data access and storage, issue commands, and control other desired operations. The processing circuit1210may include circuitry configured to implement desired programming provided by appropriate media in at least one example. For example, the processing circuit1210may be implemented as one or more processors, one or more controllers, and/or other structure configured to execute executable programming. Examples of the processing circuit1210may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may include a microprocessor, as well as any conventional processor, controller, microcontroller, or state machine. The processing circuit1210may also be implemented as a combination of computing components, such as a combination of a DSP and a microprocessor, a number of microprocessors, one or more microprocessors in conjunction with a DSP core, an ASIC and a microprocessor, or any other number of varying configurations. These examples of the processing circuit1210are for illustration and other suitable configurations within the scope of the disclosure are also contemplated.

According to one or more aspects of the disclosure, the processing circuit1210may be adapted to perform any or all of the features, processes, functions, operations and/or routines for any or all of the apparatuses described herein. For example, the processing circuit1210may be configured to perform any of the steps, functions, and/or processes described with respect toFIGS. 13-17. As used herein, the term “adapted” in relation to the processing circuit1210may refer to the processing circuit1210being one or more of configured, employed, implemented, and/or programmed to perform a particular process, function, operation and/or routine according to various features described herein.

The processing circuit1210may be a specialized processor, such as an application specific integrated circuit (ASIC) that serves as a means for (e.g., structure for) carrying out any one of the operations described in conjunction withFIGS. 13-17. The processing circuit1210serves as one example of a means for transmitting and/or a means for receiving. In some implementations, the processing circuit1210incorporates the functionality of the SNP controller250ofFIG. 2.

According to at least one example of the apparatus1200, the processing circuit1210may include one or more of a circuit/module for communicating1220, a circuit/module for selecting a subset of satellites1222, a circuit/module for identifying1224, a circuit/module for sending1226, a circuit/module for generating1228, a circuit/module for selecting a subset of ephemeris elements1230. In various implementations, the circuit/module for communicating1220, the circuit/module for selecting a subset of satellites1222, the circuit/module for identifying1224, the circuit/module for sending1226, the circuit/module for generating1228, or the circuit/module for selecting a subset of ephemeris elements1230may correspond, at least in part, to the SNP controller250ofFIG. 2.

The circuit/module for communicating1220may include circuitry and/or programming (e.g., code for communicating1232, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, communicating information. In some implementations, the information is UT location information. In some implementations, the communication involves receiving. In some implementations, the communication involves sending (e.g., transmitting). In some implementations, the information is a request. In some implementations, the information is a response. In some implementations, the information is satellite ephemeris information. In some implementations, the information is an indication.

In some scenarios, the communicating involves the circuit/module for communicating1220receiving information directly from a device that transmitted the information or receiving information from a component of the apparatus1200(e.g., the receiver1216, the memory device1208, the communication interface1202(e.g., a digital subsystem or an RF subsystem), or some other component). In this case, the circuit/module for communicating1220may process (e.g., decode) the received information. The circuit/module for communicating1220then outputs the received information to a component of the apparatus1200(e.g., the memory device1208or some other component).

In some scenarios, the communicating involves sending information to another component of the apparatus1200(e.g., the transmitter1214) for transmission to another device or sending information directly to an ultimate destination (e.g., if the circuit/module for communicating1220includes a transmitter). In this case, the circuit/module for communicating1220initially obtains information to be communicated (e.g., from the memory device1208or some other component). The circuit/module for communicating1220may process (e.g., encode) the information to be transmitted. The circuit/module for communicating1220then causes the information to be transmitted. For example, the circuit/module for communicating1220can directly transmit the information or pass the information to the transmitter1214or the communication interface1202(e.g., a digital subsystem or an RF subsystem) for subsequent radio frequency (RF) transmission.

In some implementations, the communication interface1202includes the circuit/module for communicating1220and/or the code for communicating1232. In some implementations, the circuit/module for communicating1220is a transceiver. In some implementations, the circuit/module for communicating1220is configured to control the communication interface1202(e.g., a transceiver) to receive the information.

The circuit/module for selecting a subset of satellites1222may include circuitry and/or programming (e.g., code for selecting a subset of satellites1234, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, selecting a subset of satellites based on a location of a satellite, a refresh period, or a local latitude. Initially, the circuit/module for selecting a subset of satellites1222receives ephemeris information and the other information (e.g., an indication of the location, the refresh period, or the local latitude) from the memory device1208, or some other component of the apparatus1200. In some implementations, the circuit/module for selecting a subset of satellites1222selects the subset by determining, based on the ephemeris information, which satellites are near that location or latitude or selects the subset (e.g., the number of satellites) based on the refresh period. The circuit/module for selecting a subset of satellites1222may then output an indication of this selection (e.g., to the memory device1208or some other component of the apparatus1200).

The circuit/module for identifying1224may include circuitry and/or programming (e.g., code for identifying1236, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, identifying satellite ephemeris information to be sent to a particular UT. Initially, the circuit/module for identifying1224receives an identifier of the UT (e.g., from the memory device1208, or some other component of the apparatus1200). In some implementations, the circuit/module for identifying1224identifies, based on the location of the UT, which satellites are near the UT. The circuit/module for identifying1224may then output an indication of the corresponding ephemeris information (e.g., to the memory device1208or some other component of the apparatus1200).

The circuit/module for sending1226may include circuitry and/or programming (e.g., code for sending1238, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, sending information to another apparatus (e.g., via a satellite). In some implementations, the information is ephemeris information. In some implementations, the information is ephemeris elements. Initially, the circuit/module for sending1226obtains the information to be sent (e.g., from the memory device1208, the circuit/module for identifying1224, the circuit/module for selecting1224, or some other component). The circuit/module for sending1226may then format the information for sending (e.g., according to a protocol, etc.). The circuit/module for sending1226then causes the information to be sent via a wireless communication medium (e.g., via satellite signaling). To this end, the circuit/module for sending1226may send the data to the communication interface1202(e.g., a digital subsystem or an RF subsystem) or some other component for transmission. In some implementations, the communication interface1202includes the circuit/module for sending1226and/or the code for sending1238. In some implementations, the circuit/module for sending1226is a transceiver or a transmitter. In some implementations, the circuit/module for communicating1220performs the functions of the circuit/module for sending1226. In some implementations, the circuit/module for sending1226is configured to control the communication interface1202(e.g., a transceiver or a transmitter) to send the information.

The circuit/module for generating1228may include circuitry and/or programming (e.g., code for generating1240, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, generating an indication of when a user terminal should refresh satellite ephemeris information maintained at the user terminal. Initially, the circuit/module for generating1228receives an identifier of the UT (e.g., from the memory device1208, or some other component of the apparatus1200). In some implementations, the circuit/module for generating1228determines, based on a refresh period or an expiry time, that the UT should re-read the BIBe. The circuit/module for generating1228may then output an indication of this determination (e.g., to the memory device1208, the circuit/module for communicating1220, or some other component of the apparatus1200).

The circuit/module for selecting a subset of ephemeris elements1230may include circuitry and/or programming (e.g., code for selecting a subset of ephemeris elements1242, with this code being stored on the storage medium1204) adapted to perform several functions relating to, for example, selecting a subset of ephemeris elements from a set of ephemeris elements. Initially, the circuit/module for selecting a subset of ephemeris elements1230receives ephemeris information and the other information (e.g., an indication of a UT location, an indication of the members of the subset, etc.) from the memory device1208, or some other component of the apparatus1200. In some implementations, the circuit/module for selecting a subset of ephemeris elements1230selects the subset based on this information. The circuit/module for selecting a subset of ephemeris elements1230may then output an indication of this selection (e.g., to the memory device1208, the circuit/module for sending1226, or some other component of the apparatus1200).

As mentioned above, programming stored on the storage medium1204, when executed by the processing circuit1210, causes the processing circuit1210to perform one or more of the various functions and/or process operations described herein. For example, the programming, when executed by the processing circuit1210, may cause the processing circuit1210to perform the various functions, steps, and/or processes described herein with respect toFIGS. 13-17in various implementations. As shown inFIG. 12, the storage medium1204may include one or more of the code for communicating1232, the code for selecting a subset of satellites1234, the code for identifying1236, the code for sending1238, the code for generating1240, or the code for selecting a subset of ephemeris elements1242.

First Example Process

FIG. 13illustrates a process1300for communication in accordance with some aspects of the disclosure. The process1300may take place within a processing circuit (e.g., the processing circuit1210ofFIG. 12), which may be located in an SNP or some other suitable apparatus. In some implementations, the process1300may be performed by an SNP for at least one non-geosynchronous satellite. Of course, in various aspects within the scope of the disclosure, the process1300may be implemented by any suitable apparatus capable of supporting communication operations.

At block1302, an apparatus (e.g., an SNP) communicates (e.g., receives) a request for satellite ephemeris information. In some scenarios, the request may specify whether it is for the full ephemeris information (for all of the satellites in the constellation) or for a part (e.g., a subset) of the full ephemeris information (for a corresponding part of the satellites in the constellation). In some implementations, the circuit/module for communicating1220ofFIG. 12performs the operations of block1302. In some implementations, the code for communicating1232ofFIG. 12is executed to perform the operations of block1302.

At block1304, the apparatus communicates (e.g., sends) a response to the request, wherein the response comprises the satellite ephemeris information. In some scenarios where the request of block1302specifies the requested information (e.g., full or subset), the response will only include the requested information. In some implementations, the circuit/module for communicating1220ofFIG. 12performs the operations of block1304. In some implementations, the code for communicating1232ofFIG. 12is executed to perform the operations of block1304.

In some aspects, the satellite ephemeris information consists of a quantity of ephemeris information elements. A first subset of the ephemeris information elements may be for satellite identifier and epoch time information, while a second subset of the ephemeris information elements is for elements of ephemeris other than satellite identifier and epoch time information (e.g., essential elements of ephemeris). In some aspects, each ephemeris information element of the second subset consists of, at most, three bytes of data or, at most, two bytes of data.

Second Example Process

FIG. 14illustrates a process1400for communication in accordance with some aspects of the disclosure. In some aspects, the process1400may be performed in conjunction with (e.g., as part of or in addition to) the process1300ofFIG. 13. The process1400may take place within a processing circuit (e.g., the processing circuit1210ofFIG. 12), which may be located in an SNP or some other suitable apparatus. In some implementations, the process1400may be performed by an SNP for at least one non-geosynchronous satellite. Of course, in various aspects within the scope of the disclosure, the process1400may be implemented by any suitable apparatus capable of supporting communication operations.

At block1402, an apparatus (e.g., an SNP) selects a subset of satellites in a constellation of satellites. For example, the satellites may be selected based on at least one of: a location of a satellite that transmits (e.g., relays) satellite ephemeris information (e.g., for a subset of satellites), a refresh period for at least one user terminal, a local latitude, or any combination thereof. In some aspects, the refresh period may correspond to a time for re-reading a BIBe. In some implementations, the circuit/module for selecting a subset of satellites1222ofFIG. 12performs the operations of block1402. In some implementations, the code for selecting a subset of satellites1234ofFIG. 12is executed to perform the operations of block1304.

At block1404, the apparatus communicates a message comprising satellite ephemeris information. In some aspects, the satellite ephemeris information may be for the subset of satellites. In some aspects, the communication may be a response to a request for the satellite ephemeris information. In some aspects, the communicating of the satellite ephemeris information at block1404may include at least one of: broadcasting the satellite ephemeris information, sending the satellite ephemeris information via a unicast message, or any combination thereof. In some implementations, the circuit/module for communicating1220ofFIG. 12performs the operations of block1404. In some implementations, the code for communicating1232ofFIG. 12is executed to perform the operations of block1404.

Third Example Process

FIG. 15illustrates a process1500for communication in accordance with some aspects of the disclosure. In some aspects, the process1500may be performed in conjunction with (e.g., as part of or in addition to) the process1300ofFIG. 13. The process1500may take place within a processing circuit (e.g., the processing circuit1210ofFIG. 12), which may be located in an SNP or some other suitable apparatus. In some implementations, the process1500may be performed by an SNP for at least one non-geosynchronous satellite. Of course, in various aspects within the scope of the disclosure, the process1500may be implemented by any suitable apparatus capable of supporting communication operations.

At block1502, an apparatus (e.g., an SNP) identifies satellite ephemeris information (e.g., other satellite ephemeris information) to be sent to a particular user terminal. In some scenarios, the identified information may be the full ephemeris information (for all of the satellites in the constellation) or for a subset of the full ephemeris information (for a subset of the satellites in the constellation). In some implementations, the circuit/module for identifying1224ofFIG. 12performs the operations of block1502. In some implementations, the code for identifying1236ofFIG. 12is executed to perform the operations of block1502.

At block1504, the apparatus sends the satellite ephemeris information to the particular user terminal via a unicast message. In some implementations, the circuit/module for sending1226ofFIG. 12performs the operations of block1504. In some implementations, the code for sending1238ofFIG. 12is executed to perform the operations of block1504.

Fourth Example Process

FIG. 16illustrates a process1600for communication in accordance with some aspects of the disclosure. In some aspects, the process1600may be performed in conjunction with (e.g., as part of or in addition to) the process1300ofFIG. 13. The process1600may take place within a processing circuit (e.g., the processing circuit1210ofFIG. 12), which may be located in an SNP or some other suitable apparatus. In some implementations, the process1600may be performed by an SNP for at least one non-geosynchronous satellite. Of course, in various aspects within the scope of the disclosure, the process1600may be implemented by any suitable apparatus capable of supporting communication operations.

At block1602, an apparatus (e.g., an SNP) generates an indication of when a user terminal should refresh satellite ephemeris information (e.g., other satellite ephemeris information) maintained at the user terminal. In some aspects, refreshing the satellite ephemeris information may include re-reading a BIBe. In some implementations, the circuit/module for generating1228ofFIG. 12performs the operations of block1602. In some implementations, the code for generating1240ofFIG. 12is executed to perform the operations of block1602.

At block1604, an apparatus (e.g., an SNP) communicates (e.g., sends) the indication generated at block1602. In some implementations, the circuit/module for communicating1220ofFIG. 12performs the operations of block1604. In some implementations, the code for communicating1232ofFIG. 12is executed to perform the operations of block1604.

Fifth Example Process

FIG. 17illustrates a process1700for communication in accordance with some aspects of the disclosure. In some aspects, the process1700may be performed in conjunction with (e.g., as part of or in addition to) the process1300ofFIG. 13. The process1700may take place within a processing circuit (e.g., the processing circuit1210ofFIG. 12), which may be located in an SNP or some other suitable apparatus. In some implementations, the process1700may be performed by an SNP for at least one non-geosynchronous satellite. Of course, in various aspects within the scope of the disclosure, the process1700may be implemented by any suitable apparatus capable of supporting communication operations.

At block1702, an apparatus (e.g., an SNP) selects a subset of ephemeris elements from a set of ephemeris elements. In some implementations, the circuit/module for selecting a subset of ephemeris elements1230ofFIG. 12performs the operations of block1702. In some implementations, the code for selecting a subset of ephemeris elements1240ofFIG. 12is executed to perform the operations of block1702.

At block1704, an apparatus (e.g., an SNP) sends the selected subset of ephemeris elements to a user terminal. In some implementations, the circuit/module for sending1226ofFIG. 12performs the operations of block1704. In some implementations, the code for sending1238ofFIG. 12is executed to perform the operations of block1704.

Second Example Apparatus

FIG. 18illustrates a block diagram of an example hardware implementation of another apparatus1800configured to communicate according to one or more aspects of the disclosure. For example, the apparatus1800could embody or be implemented within a UT or some other type of device that supports satellite communication. In various implementations, the apparatus1800could embody or be implemented within a vehicular component, or any other electronic device having circuitry.

The apparatus1800includes a communication interface (e.g., at least one transceiver)1802, a storage medium1804, a user interface1806, a memory device1808(e.g., storing ephemeris information1818), and a processing circuit (e.g., at least one processor)1810. In various implementations, the user interface1806may include one or more of: a keypad, a display, a speaker, a microphone, a touchscreen display, of some other circuitry for receiving an input from or sending an output to a user. The communication interface1802may be coupled to one or more antennas1812, and may include a transmitter1814and a receiver1816. In general, the components ofFIG. 18may be similar to corresponding components of the apparatus1200ofFIG. 12.

According to one or more aspects of the disclosure, the processing circuit1810may be adapted to perform any or all of the features, processes, functions, operations and/or routines for any or all of the apparatuses described herein. For example, the processing circuit1810may be configured to perform any of the steps, functions, and/or processes described with respect toFIGS. 19-22. As used herein, the term “adapted” in relation to the processing circuit1810may refer to the processing circuit1810being one or more of configured, employed, implemented, and/or programmed to perform a particular process, function, operation and/or routine according to various features described herein.

The processing circuit1810may be a specialized processor, such as an application specific integrated circuit (ASIC) that serves as a means for (e.g., structure for) carrying out any one of the operations described in conjunction withFIGS. 19-24. The processing circuit1810serves as one example of a means for transmitting and/or a means for receiving. In various implementations, the processing circuit1810may incorporate the functionality of the control processor420ofFIG. 4.

According to at least one example of the apparatus1800, the processing circuit1810may include one or more of a circuit/module for communicating1820, a circuit/module for determining whether ephemeris information is older than an age threshold1822, a circuit/module for obtaining additional ephemeris information1824, a circuit/module for refreshing ephemeris information1826, a circuit/module for receiving ephemeris information1828, or a circuit/module for calculating1830. In various implementations, the circuit/module for communicating1820, the circuit/module for determining whether ephemeris information is older than an age threshold1822, the circuit/module for obtaining additional ephemeris information1824, the circuit/module for refreshing ephemeris information1826, the circuit/module for receiving ephemeris information1828, and the circuit/module for calculating1830may correspond, at least in part, to the control processor420ofFIG. 4.

The circuit/module for communicating1820may include circuitry and/or programming (e.g., code for communicating1832, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, communicating information. In some implementations, the communication involves receiving. In some implementations, the communication involves sending (e.g., transmitting). In some implementations, the information is a request. In some implementations, the information is a response. In some implementations, the information is UT location information. In some implementations, the information is satellite ephemeris information. In some implementations, the information is an indication.

In some scenarios, the communicating involves the circuit/module for communicating1820receiving information directly from a device that transmitted the information or receiving information from a component of the apparatus1800(e.g., the receiver1816, the memory device1808, the communication interface1802(e.g., a transmitter and receiver), or some other component). In this case, the circuit/module for communicating1820may process (e.g., decode) the received information. The circuit/module for communicating1820then outputs the received information to a component of the apparatus1800(e.g., the memory device1808or some other component).

In some scenarios, the communicating involves sending information to another component of the apparatus1800(e.g., the transmitter1814) for transmission to another device or sending information directly to an ultimate destination (e.g., if the circuit/module for communicating1820includes a transmitter). In this case, the circuit/module for communicating1820initially obtains information to be communicated (e.g., from the memory device1808or some other component). The circuit/module for communicating1820may process (e.g., encode) the information to be transmitted. The circuit/module for communicating1820then causes the information to be transmitted. For example, the circuit/module for communicating1820can directly transmit the information or pass the information to the transmitter1814or the communication interface1802(e.g., a transmitter and receiver) for subsequent radio frequency (RF) transmission.

In some implementations, the communication interface1802includes the circuit/module for communicating1820and/or the code for communicating1832. In some implementations, the circuit/module for communicating1820is a transceiver. In some implementations, the circuit/module for communicating1820is configured to control the communication interface1802(e.g., a transceiver) to receive the information.

The circuit/module for determining whether ephemeris information is older than an age threshold1822may include circuitry and/or programming (e.g., code for determining whether ephemeris information is older than an age threshold1834, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, determining the age of ephemeris information. Initially, the circuit/module for determining whether ephemeris information is older than an age threshold1822obtains the threshold and an indication of the age of the ephemeris information from the memory device1208, or some other component of the apparatus1200. In some implementations, the circuit/module for determining whether ephemeris information is older than an age threshold1822compares this age to the threshold. The circuit/module for determining whether ephemeris information is older than an age threshold1822may then output an indication of this comparison (e.g., to the memory device1808, the circuit/module for obtaining additional ephemeris information1824, or some other component of the apparatus1800).

The circuit/module for obtaining additional ephemeris information1824may include circuitry and/or programming (e.g., code for obtaining additional ephemeris information1836, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, requesting ephemeris information. Initially, the circuit/module for obtaining additional ephemeris information1824receives an indication of the determination by the circuit/module for determining whether ephemeris information is older than an age threshold1822(e.g., from the memory device1208, the circuit/module for determining whether ephemeris information is older than an age threshold1822, or some other component of the apparatus1200). In some implementations, the circuit/module for obtaining additional ephemeris information1824generates a request if the information is too old. The circuit/module for obtaining additional ephemeris information1824may cause the request to be sent to the satellite system (e.g., by sending an indication to the memory device1808, the circuit/module for communicating1820, or some other component of the apparatus1800).

The circuit/module for refreshing ephemeris information1826may include circuitry and/or programming (e.g., code for refreshing ephemeris information1838, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, refreshing ephemeris information stored at a UT. Initially, the circuit/module for refreshing ephemeris information1826receives ephemeris information (e.g., from the memory device1208or some other component of the apparatus1200). In some implementations, the circuit/module for obtaining additional ephemeris information1824obtains current ephemeris information by re-reading a BIBe. The circuit/module for refreshing ephemeris information1826then updates the locally stored ephemeris information (e.g., by writing to the memory device1808or some other component of the apparatus1800).

The circuit/module for receiving ephemeris information1828may include circuitry and/or programming (e.g., code for receiving ephemeris information1840, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, receiving ephemeris information at a UT. Initially, the circuit/module for receiving ephemeris information1828obtains received information. For example, the circuit/module for receiving ephemeris information1828may obtain this information from a component of the apparatus1800such as the communication interface1802(e.g., receiver), the memory device1808, or some other component. As another example, the circuit/module for receiving ephemeris information1828may receive information directly from a device (e.g., a satellite) that relayed the information to the user terminal. In some implementations, the circuit/module for receiving ephemeris information1828identifies a memory location of a value in the memory device1808and invokes a read of that location. In some implementations, the circuit/module for receiving ephemeris information1828processes (e.g., decodes) the received information. The circuit/module for receiving ephemeris information1828outputs the received information (e.g., stores the received information in the memory device1808or sends the information to another component of the apparatus1800). In some implementations, the communication interface1802includes the circuit/module for receiving ephemeris information1828and/or the code for receiving ephemeris information1840. In some implementations, the circuit/module for receiving ephemeris information1828is a transceiver or a receiver. In some implementations, the circuit/module for receiving ephemeris information1828is configured to control the communication interface1802(e.g., a transceiver or a receiver) to receive the information.

The circuit/module for calculating1830may include circuitry and/or programming (e.g., code for calculating1842, with this code being stored on the storage medium1804) adapted to perform several functions relating to, for example, calculating an ephemeris element or rate information. Initially, the circuit/module for calculating1830obtains ephemeris information from the memory device1208, the circuit/module for receiving ephemeris information1828, or some other component of the apparatus1200. The circuit/module for calculating1830then determines an ephemeris element or rate information based on the ephemeris information. The circuit/module for calculating1830may then output an indication of this determination (e.g., to the memory device1808or some other component of the apparatus1800).

As mentioned above, programming stored by the storage medium1804, when executed by the processing circuit1810, causes the processing circuit1810to perform one or more of the various functions and/or process operations described herein. For example, the programming, when executed by the processing circuit1810, may cause the processing circuit1810to perform the various functions, steps, and/or processes described herein with respect toFIGS. 19-24in various implementations. As shown inFIG. 18, the storage medium1804may include one or more of the code for communicating1832, the code for determining whether ephemeris information is older than an age threshold1834, the code for obtaining additional ephemeris information1836, the code for refreshing ephemeris information1838, the code for receiving ephemeris information1840, or the code for calculating1842.

Sixth Example Process

FIG. 19illustrates a process1900for communication in accordance with some aspects of the disclosure. The process1900may take place within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process1900may be implemented by any suitable apparatus capable of supporting communication operations.

At block1902, an apparatus (e.g., a UT) communicates (e.g., sends) a request for satellite ephemeris information. In some implementations, the circuit/module for communicating1820ofFIG. 18performs the operations of block1902. In some implementations, the code for communicating1832ofFIG. 18is executed to perform the operations of block1902.

At block1904, the apparatus communicates (e.g., receives) a response to the request, wherein the response comprises the satellite ephemeris information. In some implementations, the circuit/module for communicating1820ofFIG. 18performs the operations of block1904. In some implementations, the code for communicating1832ofFIG. 18is executed to perform the operations of block1904.

Seventh Example Process

FIG. 20illustrates a process2000for communication in accordance with some aspects of the disclosure. In some aspects, the process2000may be performed in conjunction with (e.g., as part of or in addition to) the process1900ofFIG. 19. The process2000may take place, at least in part, within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process2000may be implemented by any suitable apparatus capable of supporting communication operations.

At block2002, an apparatus (e.g., a UT) communicates satellite ephemeris information. In some aspects, the satellite ephemeris information may be for a subset of satellites in a constellation of satellites. In some aspects, the communication of the satellite ephemeris information involves receiving the satellite ephemeris information at a user terminal (e.g., a UT receives a message including satellite ephemeris information). In some implementations, the circuit/module for communicating1820ofFIG. 18performs the operations of block2002. In some implementations, the code for communicating1832ofFIG. 18is executed to perform the operations of block2002.

At block2004, the apparatus tracks the subset of satellites based on the satellite ephemeris information. In some implementations, the circuit/module for communicating1820ofFIG. 18performs the operations of block2004. In some implementations, the code for communicating1832ofFIG. 18is executed to perform the operations of block2004.

Eighth Example Process

FIG. 21illustrates a process2100for communication in accordance with some aspects of the disclosure. In some aspects, the process2100may be performed in conjunction with (e.g., as part of or in addition to) the process1900ofFIG. 19. The process2100may take place, at least in part, within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process2100may be implemented by any suitable apparatus capable of supporting communication operations.

At block2102, an apparatus (e.g., a UT) communicates (e.g., receives) an indication of when a user terminal should refresh satellite ephemeris information (e.g., other satellite ephemeris information) maintained at the user terminal. In some implementations, the circuit/module for communicating1820ofFIG. 18performs the operations of block2102. In some implementations, the code for communicating1832ofFIG. 18is executed to perform the operations of block2102.

At block2104, the apparatus refreshes the satellite ephemeris information maintained at the user terminal at a time indicated by the indication. In some aspects, refreshing the satellite ephemeris information may include re-reading a BIBe. In some implementations, the circuit/module for refreshing ephemeris information1826ofFIG. 18performs the operations of block2104. In some implementations, the code for refreshing ephemeris information1838ofFIG. 18is executed to perform the operations of block2104.

Ninth Example Process

FIG. 22illustrates a process2200for communication in accordance with some aspects of the disclosure. In some aspects, the process2200may be performed in conjunction with (e.g., as part of or in addition to) the process1900ofFIG. 19. The process2200may take place, at least in part, within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process2200may be implemented by any suitable apparatus capable of supporting communication operations.

At block2202, an apparatus (e.g., a UT) determines whether satellite ephemeris information stored at a UT is older than an age threshold. In some implementations, the circuit/module for determining whether ephemeris information is older than a threshold1822ofFIG. 18performs the operations of block2202. In some implementations, the code for determining whether ephemeris information is older than a threshold1834ofFIG. 18is executed to perform the operations of block2202.

At block2204, the apparatus obtains additional satellite ephemeris information if the determination indicates that the stored satellite ephemeris information is older than the age threshold. In some implementations, the circuit/module for obtaining additional ephemeris information1824ofFIG. 18performs the operations of block2204. In some implementations, the code for obtaining additional ephemeris information1836ofFIG. 18is executed to perform the operations of block2204.

Tenth Example Process

FIG. 23illustrates a process2300for communication in accordance with some aspects of the disclosure. In some aspects, the process2300may be performed in conjunction with (e.g., as part of or in addition to) the process1900ofFIG. 19. The process2300may take place, at least in part, within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process2300may be implemented by any suitable apparatus capable of supporting communication operations.

At block2302, an apparatus (e.g., a UT) receives satellite ephemeris information. In some implementations, the circuit/module for receiving ephemeris information1828ofFIG. 18performs the operations of block2302. In some implementations, the code for receiving ephemeris information1840ofFIG. 18is executed to perform the operations of block2302.

At block2304, the apparatus calculates at least one satellite ephemeris element. In some aspects, the calculation may be based on the satellite ephemeris information received at block2302. In some implementations, the circuit/module for calculating1830ofFIG. 18performs the operations of block2304. In some implementations, the code for calculating1842ofFIG. 18is executed to perform the operations of block2304.

Eleventh Example Process

FIG. 24illustrates a process2400for communication in accordance with some aspects of the disclosure. In some aspects, the process2400may be performed in conjunction with (e.g., as part of or in addition to) the process1900ofFIG. 19. The process2400may take place, at least in part, within a processing circuit (e.g., the processing circuit1810ofFIG. 18), which may be located in a UT or some other suitable apparatus. Of course, in various aspects within the scope of the disclosure, the process2400may be implemented by any suitable apparatus capable of supporting communication operations.

At block2402, an apparatus (e.g., a UT) receives satellite ephemeris information. In some implementations, the circuit/module for receiving ephemeris information1828ofFIG. 18performs the operations of block2402. In some implementations, the code for receiving ephemeris information1840ofFIG. 18is executed to perform the operations of block2402.

At block2404, the apparatus calculates rate information associated with the satellite ephemeris information. In some aspects, the calculation may be based on the satellite ephemeris information received at block2402. In some aspects, the rate information may be associated with satellite inclination or satellite angle. In some implementations, the circuit/module for calculating1830ofFIG. 18performs the operations of block2404. In some implementations, the code for calculating1842ofFIG. 18is executed to perform the operations of block2404.

Additional Aspects

The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the aspects. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Moreover, it is understood that the word “or” has the same meaning as the Boolean operator “OR,” that is, it encompasses the possibilities of “either” and “both” and is not limited to “exclusive or” (“XOR”), unless expressly stated otherwise. It is also understood that the symbol “/” between two adjacent words has the same meaning as “or” unless expressly stated otherwise. Moreover, phrases such as “connected to,” “coupled to” or “in communication with” are not limited to direct connections unless expressly stated otherwise.