System and method for predicting communication link quality

Abstract

To provide a method for a terminal to predict link quality or at least a useful alternative to existing methods, a communication system, and a computer readable medium.SOLUTION: A terminal 10 monitors one or more transmission links from one or more transmission sides (for example, satellites 20) and uses information to determine a link quality estimate. The link quality estimate is for determining one or more transmission parameters for transmission from a transmitting side to a receiving side, or determining the installation position and orientation of a terminal for transmission to the receiving side or for reception from the transmitting side, may be obtained by monitoring a plurality of satellites, including Global Navigation System satellites, and may include estimating a spatial map. The link quality estimate may also be used to schedule transmission to maximize the probability of reception.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] [Priority document] This application is directed to a "System and Method for Predicting Communication Link Quality" Method for Prediction of Communications The Australian Government's "Link Quality" Act, filed on August 28, 2018, Priority is claimed from Provisional Patent Application No. 2017903470, the entire contents of which are incorporated herein by reference. and is incorporated herein by reference.

[0002] The present disclosure relates to a wireless communication system. on predicting link quality.

[0003] [Incorporated by reference] The following co-pending patent and PCT applications are incorporated herein by reference: and the contents of which are incorporated herein by reference in their entireties. Australian Provisional Patent Application No. 2016905314, entitled "Extended Satellite Ephemeris" SYSTEM AND METHOD FOR GENERATING RISK DATA OR GENERATING EXTENDED SATELLITE EPHEMER IS DATA) filed on December 22, 2016, International Patent Application No. PCT / AU2017 / 000058, filed February 24, 2017 The title of the document is "Terminal Scheduling Method in Satellite Communication System (TERMINAL S CHEDULING METHOD IN SATELLITE COMMUNICAT ION SYSTEM), applicant Myriota Pty Ltd., and International Patent Application No. PCT / AU2017 / 000108, filed May 16, 2017 The name of the project is "POSITION ESTIMATION IN LOW-EARTH ORBIT SATELLITE COMMUNICATION SYSTEMS" MATION IN A LOW EARTH ORBIT SATELLITE CO MMUNICATIONS SYSTEM" Applicant Myriota Pty Ltd .. [Background technology]

[0004] Machine-to-machine communication for small, low-cost sensors and devices located in remote areas There is an increasing demand for connectivity in machines. In many cases, terminal devices (or The equipment is installed in a fixed location or deployed in applications where it is not frequently moved. Applications include pumps, tank level gauges, utility metering, and soil moisture probes. This includes telemetry of devices such as sensors.

[0005] Many of these applications are located in areas that do not have terrestrial communication networks such as cellular. and the cost of deploying a dedicated local wireless solution is prohibitive. Satellite-based solutions are attractive.

[0006] The following characteristics of the wireless communication channel between the sender and receiver affect the quality of the link: vinegar. Link Distance: Attenuation due to free space propagation loss increases as the distance between the sender and receiver increases. and increases. Shadowing: Increased attenuation caused by obstacles between devices, such as buildings. Polarization: Variation in received signal strength due to mismatch in antenna polarization. Interference: As the receiver moves, additional signal sources appear in the received signal, causing interference. These signal sources are transmitters of the same system as the receiver. or may originate from an external system. Multipath: Signal reflections from objects in the environment cause multiple instances ( the signals (shifted in time, phase, and signal strength) arrive at the receiver via different paths, This may affect the performance of the receiver. Furthermore, the relative motion between the sender and receiver affects the quality of the link due to variations in channel conditions. It could bring about change.

[0007] The terminal device is a device between a terminal transmitter (or receiver) and a mobile receiver (or transmitter). It may be installed in a position where the path is partially obstructed, e.g., it may not be possible to see the sky in all directions. The deployment of such systems in low Earth orbit (LEO) satellite systems is not possible. In this case, the satellite receiver may attempt to transmit during periods when it is obstructed by an obstacle. In contrast, when the satellite is in line of sight of the terminal, the probability of successful reception may be reduced. By transmitting the signal, the chances of successful reception can be improved.

[0008] The terminal device may be located in a remote location where the cost of repeated site visits is too high. In fixed installation scenarios, determine whether the installation location is likely to be conducive to the success of the service. It is advisable to provide feedback to installers to ensure that non-real-time satellite services are For example, the number of short-term satellite pass opportunities per day is somewhat lower. It is not feasible to plan installations to coincide with star transits. Furthermore, these installations Typically, a cellular or other communication means that provides an instantaneous back channel to the installer. It is carried out in an area where there is no Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, it is necessary for the terminal device to predict the link quality, or at least to use existing methods. What is needed is a method that provides a useful alternative. [Means for solving the problem]

[0010] According to a first aspect, there is provided a method for estimating link quality in a communication system, the method comprising: The law is monitoring one or more transmission links from one or more senders; determining a link quality estimate; Using the link quality estimate, one or more Determines transmission parameters or terminals for transmission to or reception from a receiver. and determining the installation position and / or orientation of the terminal.

[0011] In one form, the step of determining the link quality estimate comprises: by the terminal based on the expected received signal strength for a transmission from the terminal to the receiver; Determining a link quality estimate, the link quality estimate being based on the expected received signal strength between the terminal and the receiver. Terminal transmit power, receive gain, and path loss based on estimates of link distance to the is estimated using an estimate of

[0012] In one form, the step of determining the link quality estimate comprises: determining an expected received signal strength for a transmission from the sender to the receiver; The expected received signal strength is calculated based on the estimated link distance, the transmitter power, and the receiver gain. and the propagation loss estimate is estimated using the step obtaining an estimate of the received signal strength observed at the receiver; Link quality estimation based on the difference between expected and observed received signal strength and estimating the value.

[0013] In one embodiment, the step of determining the link quality estimate comprises the step of: When the sender sends multiple transmissions to the receiver, multiple feedbacks from the receiver are It is estimated using the check message.

[0014] In one form, the step of determining the link quality estimates includes determining the link quality estimates for a plurality of locations of the receiver. and comparing one or more parameters of a reference link between the terminal and the receiver with the , is the spatial relative link quality estimate.

[0015] In one form, the step of determining the link quality estimate comprises determining a spatial subspace of the link quality estimate. The method includes the step of calculating Marie.

[0016] In one form, the step of determining the link quality estimate comprises: The method includes a combining step.

[0017] In a further aspect, the plurality of link quality estimates include a plurality of link quality estimates for each link between the terminal and one of the plurality of satellites. The step of combining the link quality estimates is performed by using a The method includes obtaining an aggregated link quality estimate when the link quality is within a spatial region of the signal level.

[0018] In a further aspect, the step of combining the plurality of link quality estimates comprises combining the plurality of link quality estimates over a historical period. The method includes combining a plurality of link quality estimates.

[0019] In a further aspect, the step of combining the plurality of link quality estimates is performed by the receiver. The link quality estimates between the receiver and each of the plurality of terminals are combined. The method includes providing feedback information to the plurality of terminals.

[0020] In one embodiment, the step of determining the link quality estimate comprises communicating feedback information to the terminal. The information is distributed between the terminal and components external to the terminal.

[0021] In one form, the step of determining the link quality estimate comprises: Performing multiple measurements of received signal strength from one or more transmitters at the terminal location Steps and providing the plurality of measurements as input to a model that returns a link quality estimate. nothing.

[0022] In a further aspect, the terminal location is an installation location.

[0023] In a further aspect, the measurements are made by a device external to the terminal and link quality estimates are provided to the terminal. It is served.

[0024] In one form, the communication system is a satellite communication system and includes at least one satellite and and a plurality of terminals. In one embodiment, one or more signals from one or more senders. The step of monitoring the transmission link may include monitoring one or more Global Navigation Satellite Systems (GNSS). includes monitoring one or more transmissions from a plurality of satellites.

[0025] In one form, the one or more transmission parameters include a transmission time, duration, data transfer rate, and the like. transmission speed, power, frequency, or in the case of multiple transmit antennas, which antenna or antennas In one embodiment, the present invention includes one or more of the following: , determining one or more transmission parameters for transmission from the sender to the receiver, The step of using the quality estimate includes using the success probability determined using the link quality estimate. for one or more messages each through one or more satellite passes. In a further aspect, the method includes scheduling multiple redundant transmissions. The step of scheduling transmissions includes scheduling queue priorities using link quality estimates. and determining a probability of success for one or more messages for transmission based on the determined probability of success. In a further aspect, the method further comprises queuing the message packet. The greatest opportunity for redundant replication in queues and transmissions is with the least likely to succeed. In a further aspect, the scheduling is Using an optimization method in which the signal time is restricted to a discrete grid of intervals W and time intervals T, , including multiple redundant transmissions being performed. In a further aspect, the time interval is T=[now- L,now+L]. In one embodiment, the method is determined using a link quality estimate. and transmitting one or more messages based on the determined schedule. nothing.

[0026] According to a further aspect, there is provided an antenna, communication hardware, a processor, and a method for transmitting a signal from the antenna to the receiver of the first aspect. and a memory containing instructions that configure the processor to implement the method. In a further aspect, a plurality of these terminals and one or more of the determines a link quality estimate for a terminal from information about multiple communication links and selects one or more A number of transmission parameters are transmitted to the terminal, or one or more of the terminal's installation position and orientation are transmitted. The present invention provides a method for determining whether a plurality of access nodes and a scheduler device are provided. In one embodiment, a communication system is provided, comprising: a core network for receiving a plurality of The access node of the first aspect includes a plurality of satellite access nodes. A computer-readable medium is provided that includes instructions that cause a processor to perform the method of.

[0027] Embodiments of the present disclosure will now be discussed with reference to the accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1] This is a schematic block diagram of an example installation in which a terminal is mounted on the south side of a building and is not visible from the north sky because it is shaded by the building.

[0029] [Figure 2] 1 is a schematic diagram of a terminal 10 monitoring two reference links 36 and 38 according to one embodiment.

[0030] [Figure 3] Sky view map constructed using CNR values ​​and corresponding to the relative GPS satellite positions recorded by the device during the 8-day experiment.

[0031] [Figure 4] 4 is a threshold sky-view map showing the areas in the sky-view map of Figure 3 where the CNR is above the threshold of 33 dB.

[0032] [Figure 5] 2 is a sky view map for the installation shown in FIG. 1 according to one embodiment.

[0033] [Figure 6]FIG. 2 is a schematic diagram of a terminal device according to one embodiment.

[0034] [Figure 7] 1 is a schematic diagram of a satellite communication system according to one embodiment;

[0035] [Figure 8] 1 is a flowchart of a method for estimating link quality in a communication system according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0036] In the following description, like reference numerals designate like or corresponding parts throughout the drawings. do.

[0037] Hereinafter, the end device and / or other system entities will be able to predict link quality. This paper describes methods for enabling the use of the terminals, as well as terminals for implementing these methods. In an embodiment, the method further comprises: and / or orientation. In another embodiment, the method to assist in scheduling transmissions and / or to select transmission parameters; This may be used to reduce battery consumption and extend battery life. The parameter may be used to select the transmission parameters to use for transmission to the terminal.

[0038] Referring now to FIG. 1, the terminal 10 is mounted on the south side of the building 40 and is visible from the north side. A schematic diagram is shown with the end obscured by a building. There are two communications links 30 between the satellite 20 in low Earth orbit (LEO) heading north 21. The uplink 32 transmits from the terminal 10 to the satellite 20 and The communication link 34 transmits from the satellite 20 to the terminal 10. In this example, the satellite 20 is a communication link. Although the method described herein is shown at one end of a link 20, it is also applicable to ground or airborne systems. The terminal 10 may predict the quality of the uplink 32 to the satellite 20 and use this prediction as Use it to schedule transmissions, choose transmission parameters, or select installation locations. The techniques described herein may also be applied in the reverse direction, e.g. For example, a satellite 20 (or other device) may predict the quality of a downlink 34 to a terminal 10. Furthermore, the determination of the link quality estimate may be made by the terminal only, between the terminal and a satellite or other system entities (including distributed and cloud-based components) In conjunction with, or entirely with, other technologies that provide estimates to terminals, for example as part of the installation process. may be implemented by a system entity.

[0039] In some embodiments, the link quality estimate affects the outgoing link from the terminal. In some embodiments, the long-term estimate is a measure of a permanent / semi-permanent characteristic. Estimates may be based on a small number of measurements, or on long-term historical data, or a combination of both. or changes over time, such as semi-permanent or permanent interference sources, buildings, or terrain. It may be based on measures of effects that change slowly or not at all. In this embodiment, the link quality estimates are calculated over a long period of time (months, years, or even the lifetime of the device). That is, the link quality estimate is determined and used by, for example, scheduling each transmission. While it may be used frequently, such as when routing, link quality estimates are generated and updated infrequently. For example, the generation of link quality estimates may be performed at set intervals. In other embodiments, the link quality estimate may be updated only at the time of placement and not updated thereafter. The set point may be, for example, every 3, 6, or 12 months, or when a change in position is detected, or is generated or updated infrequently, such as when the success rate decreases (e.g., packet loss increases). However, in other embodiments, the link quality estimate is calculated before each transmission or May be implemented at a higher frequency, including demand.

[0040] To aid in understanding, it is first assumed that a terminal assists in scheduling transmissions and / or Estimate link quality estimates for transmission parameter selection (i.e., standalone or standard) For example, the terminal is most preferably Transmissions can be scheduled during poor channel conditions, thus reducing shadowing. Improves reception reliability by reducing the impact of effects such as glitching, polarization mismatch, and interference. The terminal may also increase the data rate in favorable channel conditions, for example. The link quality estimate is used to adjust the transmission parameters to increase or decrease the transmission power. You can trade off metering and link quality.

[0041] Referring again to FIG. 1, the terminal 10 may be configured to time and / or time-vary with respect to the availability of the satellite receiver 20. Consider a window in space (and potentially in frequency). For example, referring to Figure 1, During the satellite pass, the LEO satellite receiver 20 was only in view of the terminal to the south for a window of a few minutes. (As the LEO satellite moves north, it becomes increasingly obscured by building 40.) In this embodiment, the terminal uses the expected location of the receiver when scheduling transmissions. Or they have some knowledge of the route, and in fact, at each point in the sending window, The approximate position of the receiver relative to the aircraft may be estimated. For example, for a satellite-based receiver, If so, the terminal may use the satellite's ephemeris data. (or orbital elements) are provided as two-row orbital elements (TLE) that model the satellite's orbit. It may be transmitted by satellite or another transmitter and stored in the terminal. In some embodiments the terminal is adapted for use with the device disclosed in Australian Provisional Patent Application No. 201690531 No. 4, titled "System and method for generating extended satellite ephemeris data (SY STEM AND METHOD FOR GENERATING EXTENDED SATELLITE EPHEMERIS DATA), filed December 22, 2016 Calculating or storing extended ephemeris data for a satellite using the method described in These extended ephemeris data may be valid for periods of one year or more. In the example where the satellite predicts the downlink quality, it may be based on a fixed position or from the terminal. The expected location of the terminal receiver may be known from previously received location information from the mobile station.

[0042] Prior to transmission, the terminal 10 obtains or determines a link quality estimate, as will be described in more detail below. and predict the probability of successful transmission to the satellite (i.e., packet reception by the satellite receiver). This estimation or prediction is then used to determine the transmission time, duration, data rate, It is used to determine one or more transmission parameters, such as power and frequency. If the terminal has multiple transmit antennas, it can select or combine the use of these antennas. In combination, polarization mismatch losses may be minimized.

[0043] The estimation may be performed one or more times in the transmission window, or one or more times along the satellite path during the transmission window. This may be performed at multiple locations (e.g., using ephemeris data). In an embodiment, the estimation process involves determining one or more transmission windows and satellite ephemeris for the windows. The input is the satellite data (or orbital path data), and the Determine multiple estimates of link quality and identify the time (and therefore location) of the best link quality. The link quality estimate (i.e., value) is then used to determine transmission parameters. It can be done using evenly spaced or time samples across the transmission window, or by using the highest link Using optimization or search techniques to find the best quality estimate, multiple estimates may be obtained. good.

[0044] Next, a method for estimating link quality will be described. Before transmission, the received signal is used to estimate the quality of the communication uplink 32. The link used is referred to as the reference link. Multiple reference links may be used, and each reference link The links are from different sources. These sources may be one or more satellite transmitters. , as well as airborne or ground transmitters (which may be fast-moving, slow-moving, or fixed) These transmission sources may also be receivers of transmissions from the terminals, It is noted that when operating in conjunction, they may be referred to as receivers. , the reference link is part of the same communication system as the communication link. A link can be a link to another system (or subsystem), such as another communications system, or to a network The transmitting source is part of a Global Navigation Satellite System (GNSS). In , a terminal has access to multiple transmission sources and therefore multiple reference links. Furthermore, the reference link may be a unidirectional link and need not be a bidirectional link. The sender may not be aware that a terminal is receiving or monitoring its transmission.

[0045] FIG. 2 illustrates a terminal 1 monitoring two reference links 36 and 38 according to one embodiment. The first reference link 34 is a schematic diagram of a satellite 200 of a satellite communication system including the terminal 10. 0, and the second reference link 38 is a downlink from the GNSS satellite 24 (e.g., G In this embodiment, a single receiver antenna is used. Although one receive antenna is shown, it should be understood that multiple receive antennas may be used. is.

[0046] In one embodiment, the terminal uses information about the reference link to estimate the expected received signal strength. This information is used to determine the reference link transmit power estimate.

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[0047] Link Distance Estimate

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[0048] In another embodiment, the link distance is calculated using the time of flight of the transmitted data to calculate the transmission time and For example, the transmitter 20 and the receiver 10 ( Once synchronized to a common clock (e.g., via GNSS), packet-based transmissions In another example, the transmission is aligned to a slot. In a time-slotted system, the receiver determines the time based on the arrival delay relative to the slot boundary. The link distance may be determined by

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[0049] In another embodiment, the relative orientation of the receiver and transmitter, as well as the antenna polarization and The gain patterns are known or can be estimated. Given the physical orientation of the system components, for a particular example of a link:

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[0050] In one embodiment, the reference link receiver is configured to calculate an estimate of the observed received power

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[0051] In another embodiment, the terminal communication link is bidirectional and the communication recipient sends an acknowledgement message. Feedback messages (or information) such as packet transmission success rate, etc. Provides the terminal with any performance statistics or CNR / SNR estimates. The acknowledgement or series of acknowledgements may be provided in real time or may be provided in baseband, for example. In distributed systems where the receiver signal processing implementation is not physically coupled to the radio receiver, In this case, the link quality metric is used to determine whether the acknowledgment is received or not. or counting the number of retries required for successful reception for a given receiver location, is a measure of other parameters such as the average packet transmission success rate when transmitting to receivers located within a certain spatial region. For example, the sky may be measured using a performance metric (e.g., azimuth and The image is divided into predetermined regions (based on elevation / vertical angle) and the data held for each predetermined spatial region is The number of times the

[0052] In another embodiment, the terminal may use information from the reference link to determine the Predict and compare the relative quality of communication links across potential receiver locations (in a region). The comparison does not require absolute calculation of the additional loss and therefore does not depend on the transmit power or antenna characteristics. For example, a terminal may be configured to use one or more GN For the SS reference link, the observed CNR value, SNR value, and the corresponding relative GNSS The satellite positions may be recorded and used as a metric to predict communication link quality. The observed CNR or SNR may also be used to determine if the reference link is a communication link. The terminal may store a record of the metrics, and may use the metrics in conjunction with other metrics such as response rate. These historical (temporal) records can be analyzed to create models that can be used to estimate link quality. can be constructed.

[0053] Channel effects, such as rain fade and ionospheric effects like Faraday rotation, are The results may be frequency dependent. The communication link and the reference link may operate at different frequencies. In this case, the link quality metric may be adjusted to take into account the relative differences in frequency-dependent effects. In some embodiments, the link quality estimate or link quality metric is Time may also be taken into account; for example, environmental effects may change with the seasons (e.g. For example, winter and summer), so link quality estimates are subject to average monthly or seasonal influences. It may contain time-varying components that incorporate resonance.

[0054] During operation, the terminal continues to calculate link quality metrics, such as additional loss or CNR, and A spatial summary of link quality estimates, such as a SkyView map, may be constructed. View Maps notifies the scheduling of data transmission from the terminal and ensures that the satellite receiver It may be used to limit transmissions that occur when it is assumed to be within line of sight.

[0055] Figure 3 shows the CNR values ​​recorded by the device during the eight-day experiment. Sky View Map 300 corresponding to the relative satellite positions for multiple GPS satellites In this example, the terminal is mounted on the south side of the building, and the building is visible from the sky on the north side. The Sky View map shows rotation in azimuth (north is 0 degrees) and radial The measurements are polar coordinates representing altitude (or elevation angle). The example provided in this figure shows This shows a reduction in CNR on the north side of the wall. The slope of wall 310 is also shown in the figure. There are also areas that GPS satellites cannot reach, such as 320. These areas are due to the satellite orbits. The parameter can be used to indicate that the link has unknown link quality. In this case, when multiple CNR observations are made at the same azimuth / altitude position, the average Instead of the mean, other functions such as the median, maximum, or minimum can be applied. It is possible.

[0056] In one embodiment, a threshold is applied to the sky view map to denote CNRs below the threshold. The samples with the highest visibility have been removed, and the remaining samples have been placed in a location that provides a less obstructed view of the sky. 1 shows areas where the satellite is less dense and therefore potentially has a higher quality communication link to the satellite. Figure 4 shows the area in the sky-view map of Figure 3 where the CNR is above the threshold of 33 dB. The threshold sky view map 400 is used as the basis for the terminal to adjust its transmission. Limiting azimuth and altitude to within the area, thereby avoiding obstructions to the north You may choose to do so.

[0057] FIG. 5 illustrates a sky view map 500 for the installation shown in FIG. 1 according to one embodiment. In this embodiment, the numbers around the Sky View map are aligned in the direction where north is 0°. The dashed circles and numbers in the Sky View map represent elevation angles, with the zenith at 90°. In this map, shading represents poor link quality, and as can be seen, The first area 510, which is northward and encompasses azimuth angles between 315° and 45°, is the area of ​​buildings north of the terminal. Indicates poor link quality due to obstruction by object 40. 300°~60° azimuth A second area 520 extending from around the corner represents medium link quality. A further area 530 of moderate (better than medium) link quality is in the 120° to 180° azimuth range. angle, and between 0° and 30° elevation angle relative to the terminal (i.e., approximately southeast horizon relative to the terminal) ) is located.

[0058] In another embodiment, the terminal receives multiple signals (e.g., from the communication system and from the GNSS). The terminal has access to a reference link receiver source. The terminal estimates the link quality based on each receiver. The estimates are then combined into an aggregate link quality estimate. Combined (i.e., spatially aggregated), an average sky map can be created. Additionally, the link quality estimate is based on an aggregate or average value for a particular receiver (i.e., (based on repeated criteria for the same receiver) or for the same type of receiver On the other hand, for example, different GNSS systems (i.e., GPS satellites, GLONASS satellites, Beidou satellites) or satellites with the same hardware (e.g., the same GPS block) It is possible to average, i.e., aggregate based on the class of receiver or reference link. For example, aggregation can be based on distance to the receiver (related to orbital position). Distance ranges / bins can be predefined and averaging is done within a given distance range. The estimation is performed for all receivers in the This includes generating error estimates so that, for example, probabilistic thresholds can be used in determining whether to For example, if there is a high reliability value in good transmission conditions, the good conditions may be more variable. A low confidence value suggests that the problem may be more likely to occur and therefore requires more attention. Compared to, the transmit power can be reduced assuming stable conditions.

[0059] In another embodiment, the terminal measures the communication link quality using a GNSS satellite signal strength metric (CN R) and the position of these GNSS satellites in the air relative to the device. Attach, store and use models and / or databases. Models or databases The process can be performed using offline experiments (conducted in a controlled environment) or simulations. or by some combination of these measures. Statistical modeling, machine learning, and data mining methods are used to model and / or In some embodiments, the database may be used to build a may be used as a look-up table and based on experiments and simulations Measurements may be derived from a model based on the known path length to the satellite. may be normalized to accommodate the expected The experiment also demonstrated that the database query predicts the communication link strength. Enough data samples are available so that a high degree of confidence can be assigned to the expected quality. Determine the test period for the minimum expected duration of GNSS satellite measurements required to provide Similarly, the database may be used to refine or refine estimates over time. may be used to update the .times. ... You can provide these to the model or use a lookup table (or These are compared to a database to generate a new set of link quality measurements to be used the following month. In some embodiments, model updates can be generated periodically by satellite. It may be provided to the terminal.

[0060] The uplink receiver measures performance metrics such as packet transmission success rate, CNR, and SNR. In a preferred embodiment, the terminal may evaluate the communication link quality based on the feedback. The uplink receiver has a back channel through which link quality information is transmitted. The terminal can provide a spatial summary of link quality estimates to the receiver, and and / or a spatial summary of link quality estimates from the receiver. It may be an (arbitrarily quantized) sky view map, or a von Mises Constructed using a distribution (or a superposition of distributions) on a sphere, such as the Fisher distribution, The terminal receives its initial link quality estimate spatial summary. The transmitter may be provided with updates thereto in the form of incremental changes, which may be exchanged with the receiver. This has the advantage that the amount of data that needs to be transmitted to the terminal is reduced. The existing link quality estimate spatial summary data may be received in whole or in part by the terminal. The data may be replaced with updated summary data that is based on the data, or may be extracted via, for example, autoregression. The receiver may then combine the two data sets. If we detect that the link quality estimate spatial summary differs significantly from the observed performance, Issue a command to the device to discard the current set of link quality estimates. You may do so.

[0061] In one embodiment, the receiver measures terminal link quality over time from one or more terminals. Maintaining a record of the estimate space summary and the corresponding link quality estimate space observed at the receiver This information is then used to adaptively adjust the link quality estimation techniques applied to the terminals. For example, new technology is being used to show clear sky views. Set a new reference link CNR threshold.

[0062] In another embodiment, the link quality prediction may also use statistics regarding interference. The terminal is instructed that one-way transmissions to the star are likely to experience greater interference. This means that when a terminal transmits in that direction, it may not be able to see other signal sources in view of the satellite. For example, region 530 in FIG. The figure shows an example of an area with more interference than a region. The prediction also includes a terrain map, and buildings. It uses information from other sources, such as information from the surrounding environment, to estimate the channel effects caused by the surrounding environment. Such effects may be permanent or semi-permanent and must be taken into account during installation. However, buildings and interference sources may change over time. Therefore, link quality estimates are updated over time to take such changes into account. may be repeated (e.g., every few months or yearly).

[0063] In one embodiment, the link quality prediction process is distributed. For example, a configuration implemented in a terminal using one or more reference links as described above. constituent elements, and It is carried out on satellite or using ground-based (e.g., cloud) processing, and the results are It may also have other components that are fed back to the terminal, such as receiver performance metrics. communication receiver processing and link quality assessment based on the standard, or link quality assessment based on terrain knowledge The quality estimation may be performed remotely from the terminal.

[0064] The terminal may receive information via the information provided in the communication downlink or in another way, e.g., via a terrestrial link. The instructions may be given via a wired communication link or through an installed wired communication link.

[0065] In another embodiment, the terminal detects that it has been moved or reoriented and If the degree of orientation is significant (e.g., compared to some threshold), the current set of link qualities You may adjust the estimate (to adjust for movement) or reset the estimate. The terminal may be equipped with systems such as GNSS and / or inertial measurement units or vibration sensors. The sensor may be used to detect movement or reorientation.

[0066] In a preferred embodiment, the transmitter uses one or more of the methods described above to Predicts quality and informs transmission schedules, targeting transmissions during the most favorable channel conditions This has several advantages: By reducing the impact of deleterious effects such as shadowing, polarization misalignment, and interference This results in improved performance. Reducing energy consumption for battery-powered devices. A number of individually attenuated signals that are not decodable but that together exist as interference Reduction of interference experienced by multi-user receivers at satellites, which is the aggregation of signals.

[0067] The transmitter may, for example, increase or decrease the data rate in favorable channel conditions. may reduce transmit power, or trade other parameters for link quality. In this state, the transmitter may, for example, choose a mode that provides minimum power consumption, maximum data rate, or maximum probability of reception. Optimize one or more objective functions with the goal of achieving a single transmit Schedules (transmission times and / or frequencies) for or across multiple transmissions ), transmission power, as well as spatial parameters (orientation of the receiver relative to the transmitter). .

[0068] In another embodiment, when a satellite is transmitting to a particular terminal (e.g., unicast), The satellite downlink transmitter receives the link quality estimate spatial summary ( Uses a network topology (e.g., a sky-view map) to estimate link quality and schedule transmissions. The downlink transmitter also sends a link quality estimate spatial summary to each terminal. may be used to schedule transmissions to multiple terminals (e.g., The sender may, for example, be an individual end-based or Minimum power consumption, maximum data rate, or maximum reception, aggregated across multiple devices The probability may be targeted to optimize one or more objective functions.

[0069] The transmissions are diverse in frequency and time, including distribution over different satellite passes. In one embodiment, packet transmissions may be scheduled to achieve redundancy. The redundant transmissions are distributed over one or more satellite passes. A message packet (or simply a packet) for transmission is sent according to the queue priority. Messages may be queued with priority based on the probability of success. Message packets are sent in a redundant queue and sent to the one with the lowest chance of success. It is queued so that it is given the greatest opportunity to be made.

[0070] As mentioned above, the link quality estimate estimates the probability of success (or failure) of a transmission. This may be used to enable probabilistic scheduling. The quality estimates are used to estimate the probability of a transmission failing as a function of time and space. For example, the probability of a transmission failure at time t may be given by: p(t)=p f (θ(t),φ(t)) where θ(t) is the azimuth angle and φ(t) is the satellite's angle relative to the terminal as a function of time. Altitude as a function of time using Sky Map or other link quality assessment functions. We can estimate these probabilities for all N messages m1, m2, ..., m N Send Assume that you need to trust

[0071] Each message is sent multiple times to increase the probability that it will be received correctly at least once. It may be transmitted. n,1 , t n,2 , …, message m n The sequence of times After the Kth transmission, m n The probability that is not received is:

number

[0072] Each message is repeated until the failure probability ρ is small enough. As an integer, q n,K(n) ≦ρ. The number of transmissions that minimizes the total number of transmissions is Sequence t n,1 , …, t n,K(n) I want to choose.

number

[0073] Two constraints can be applied: latency T and throughput W. The constraint is that all messages must be sent within a certain time interval T. (i.e., t n,k ∈T), the throughput is the minimum time W between successive transmissions (|t n,k -t n,l | ≥ W). Then, optimize either latency or throughput or both ( Scheduling can be performed by optimizing the In one embodiment, the transmission times are distributed over a discrete grid with interval W (i.e., t = lW) and optimize the allocation within the latency interval T. , the computational complexity of the optimization is reduced. Therefore, Various optimization methods are used to allocate transmission times based on the probability at each time. In one embodiment, the probabilities over the intervals are ordered and a greedy allocation method is used. For example, let I be a set of grid points at interval T, as follows: become.

number

[0074] At the end of the procedure, the transmission times are in the list t1, t2, … t N The algorithm is stored in If we finish at line 6, the target failure probability ρ is met for each message. If the algorithm terminates at line 9, then at least one message does not reach the target probability. If this is not desirable, the interval T can be increased and the algorithm repeated. In some cases, some messages are more important than others, e.g. rate ratio p n / q n By maximizing based on and replacing the termination conditions in lines 5 and 6 with , to weight some messages based on their importance (e.g., more important (High messages have a low error probability), the above algorithm can be modified. Allocation methods based on permutation, mathematical optimization, or even machine learning may also be used. stomach.

[0075] The selection of the time interval T is based on the duration of the latency L, such that T=[now, now+L]. In one embodiment, the interval T is selected as T=[now−L, now+L]. That is, in this embodiment, the scheduler determines transmission times from both the past and future. This means that the scheduler will choose to skip the transmission on the next pass. This may mean that the next satellite pass (i.e., (now+L)) If the probability of transmission is low in the near future and high in the most recent satellite pass (i.e., (now-L)), Table 2 shows the transmission time interval T, which allows the interval to include past times. This shows another scheduling algorithm. If it does, no message should be sent and the algorithm terminates at line 6. If so, the message should be sent immediately. After the procedure is finished, the value of t is Indicates the next time the ringing algorithm should be attempted. <Greedy algorithm for selecting transmission time> [Table 2]

[0076] In one embodiment, one or more of the methods described above may be used to link components at the time of installation. Predict quality and provide feedback to installers to determine whether installation location can contribute to the success of the service. In one embodiment, the terminal is powered on and receives GNSS satellite signals. Record the signal strength measurements of these GNSS satellites in the air relative to the terminal during the test period. These measurements are queried against a stored database (see above). , used to display feedback to the installer. Uses normalized measurements For example, from a satellite above the horizon, If the signal is absent or severely attenuated, the line of sight is obstructed in that direction. These methods are either performed by the terminal or by a connected host computer. Alternatively, the installation application can be run on the GNSS receiver and A stand-alone host with GNSS receiver measurement capability, e.g., a stationary terminal The system can be executed on a smartphone located in the vicinity of the user.

[0077] In one particular embodiment, the installed terminals may be configured to transmit communication links, e.g., in low-cost deployments. Such a terminal may comprise only a communication link receiver and a GNSS receiver. Since the system does not have a secondary receiver such as In this case, a dedicated device (standalone or host-connected) is used to measure link quality. Then, the device to be installed acquires a fixed baseline and constructs a spatial summary of link quality estimates. ,This link quality information is programmed before deployment.

[0078] 6 is a schematic diagram of a terminal device 10 according to one embodiment. The terminal device includes a communication module 110, the communications module including one or more antennas 112 and associated hardware and associated hardware for encoding and modulation, and transmitting the data to the satellite 20 via a radio frequency uplink 32. The data is then prepared and sent from the satellite 20 (or other source) via the downlink 34. The satellite receives data from the terminal and prepares the data for decoding. a communications module including an RF front end with one or more antennas for a transmitter module and a transmitter module, which may each comprise encoding / decoding and modulation / demodulation components; and receiver module and data (e.g., ephemeris data, configuration data) It stores satellite operation data, signal decoding, and performance data. Controls the sending and receiving of signals, including the In some embodiments, the method further comprises a processor and associated memory for performing corresponding operations. The satellite can be operated in bent-pipe mode, or digitally using store-and-forward. Operates in a standard sampling mode and performs only minimal signal processing of received transmissions or not, transmitted or received packets (by a cloud-based processor) to a ground station for further processing (including processing).

[0079] The terminal also comprises a processor module 120 and a memory 130. The memory , link quality estimate estimation, link quality spatial summary estimation, estimate update, and How the terminal uses these estimates to schedule transmissions or to adjust transmission parameters a software program that causes a processor to perform the methods described herein, including selecting a The memory also contains software instructions or software modules. quality estimates and link quality spatial summaries, as well as the methods for generating or updating such estimates. It is used to store any data, parameters, or metrics used to The memory may contain a database used to estimate link quality estimates from short-term measurements. The memory may also include one or more databases, including a database for storing the desired time. Schedulers and alarms to wake up the device (e.g., during predicted satellite pass times) It may also be used to house modules for other functions, such as power supply modules. Other components such as a clock, a sensor platform, etc. may also be included in the terminal device. stomach.

[0080] During installation and configuration, data can be transferred via e.g. Bluetooth or WiFi-based The communication module 110 communicates with other loads via a short-range wireless connection using a protocol. In some embodiments, the terminal device may be replaced with a local device. Or physically transfer (or upload) data to the device while it is under maintenance. a physical interface 150, such as a USB interface, that allows The terminal device may have a GPS receiver that can be used to provide position and time estimates. In addition, the terminal device may include a timer 140 via the communication module 110. The terminal may receive timing information, for example, when it is in service or maintenance. It may contain a stable internal clock that is periodically synchronized with UTC during operation.

[0081] FIG. 7 is a schematic diagram of a satellite communication system 1 according to an embodiment. The system 1 may be equivalently called a communication network, and includes a plurality of terminals 10 and a plurality of satellites. The core network 200 includes an access node 20. aerial and terrestrial), an access gateway 230, an authentication broker 240, and an application The broker 240 is an application gateway 250. The gateway 250 exchanges data 262 with the application 260. The information 264 can be directly controlled using the application 260. The components of the system may be distributed and communicate through a communication link. The link quality estimates can be cloud-based. The terminal or satellite can then calculate the link quality estimates. The core network scheduler performs the calculation and provides feedback information to the terminal. In addition, the terminal may provide information to a controller device that is not part of the communication system 1. Additional transmitters may be used to monitor the reference link 36, and satellite transmitters such as GNSS satellites may be used. The system may include a ground-based transmitter 22 and a ground-based transmitter 24 .

[0082] In one embodiment, system 1 uses a publisher-subscriber model. , comprising the following system entities: Terminal 10: A communication module in the terminal connects the core network to the access node. The terminal 10 has both the device 102 and the sensor 104 attached. They may be physically attached or integrated, or It may be operatively connected to the terminal through a local wired or local wireless link. Device 102: These entities, through an authentication broker, authenticate the device they are registering with. Receive the data. Sensors 104: These entities transmit data without being aware of other network nodes. The sensor also receives transient control data and issues an ACK message. It may also be possible to perform the following. Access Node 20: A plurality of access nodes provide wireless communication with a plurality of terminals. Most access nodes are satellite access nodes, but the system is based on terrestrial base stations. The satellite access node may provide access to the core network 200. to provide. Access Gateways 230: These are the gateways between the access nodes and the authentication brokers. The gateway acts as a gateway between the access node 20 (e.g., a satellite It may be combined with a Authentication Broker 240: A broker between publishers and subscribers. The message server authenticates that the received message is from a registered terminal. Application Gateway 250: A gateway that allows multiple interfaces to be used Data gateway between the application 260 and the broker 240. The interface may be a customer-controlled endpoint. Message queue template that forwards messages to a remote or customer-accessible endpoint Includes a MQTT interface. Applications 260: Customer applications. These are, for example, cloud-based Application gateways are connected to the application server through wired and wireless links. communicates with the application gateway.

[0083] Methods for enabling end devices to predict link quality and methods for realizing these methods Figure 8 shows a terminal configured to estimate the link quality of a communication system. 8 is a flowchart 800 of a method for determining whether a 10 and determining a link quality estimate 820. In step 830, the link quality estimate is used to determine whether the received link quality is correct. determining one or more transmission parameters for transmission to a receiving side or Determine the location and / or orientation of the terminal for transmission or reception from the transmitting side. Scheduling of communications is conducted by Myriota Pty Ltd., an international patent application No. T / AU2017 / 000058, filed February 24, 2017, invention title: "Satellite communications Terminal scheduling method in the system METHOD IN SATELLITE COMMUNICATION SYSTEM M) or using a stochastic method as described herein. In one embodiment, the terminal may be implemented using a scheduling method as described herein. The system includes a scheduler configured to implement the scheduling method described in . In an embodiment, the scheduler is a computer located in the core network 200. A part of a system that receives transmit link measurements from one or more terminals and The scheduler uses these link quality estimates to Determine a transmission schedule for one or more terminals and transmit the scheduling information to one or more terminals. Or, transmit it to each of multiple terminals.

[0084] An embodiment of the methods and a terminal configured to implement these methods comprises: On the other hand, especially in remote locations where the cost of repeatedly visiting the site is too high for the device The method provides a number of benefits to the terminal device (or device location). First, the method comprises: Provide installers with feedback to help them determine whether the location is likely to be conducive to successful communications services. Once the installation is done, the method determines the most favorable channel conditions for the terminal. Therefore, shadowing, polarization By reducing the influence of mismatch and interference, the probability of reception is increased. Also, for example, increasing the data rate or transmitting in favorable channel conditions. To reduce the power, link quality estimates are used to compare transmission parameters with link quality. Therefore, energy consumption can be reduced by , thus making it possible to increase battery life. Low-cost, low-power terminals are installed in remote locations where the cost of repeated site visits is too high, or The method is applicable to a satellite communication system in which an access point is connected to a satellite , solar-powered and / or battery-powered, capable of remaining airborne for extended periods (e.g., several days) aerial access points such as high-altitude unmanned aerial vehicles (UAVs), including drones or airships; A communications system, which may be a satellite (pseudolite), or a fixed or mobile terrestrial access point. The system may also be used in fully terrestrial systems located on land or offshore. communication system (i.e., complete terrestrial access points and / or terminals), or terrestrial Access points and / or terminals and airborne access points and / or The terminal can be used by a corresponding communication system.

[0085] The link quality estimate may be calculated for a particular link and time, e.g., for a particular reference link or or any hypothetical transmission to any receiver at any location relative to the terminal. In some embodiments, the link quality estimate may be generated for a fixed link. Long-term estimates, which are measurements of permanent and semi-permanent features that affect the outgoing link from the endpoint. In some embodiments, the estimate is based on a small number of measurements or on a long history. historical data, or a combination of these, or semi-permanent or permanent sources of interference, buildings , or measures of effects that change slowly or not at all with time, such as topography In some embodiments, the link quality estimate may be based on a long-term (several months) determined and used over the course of months, years, or even the lifetime of the device. may be used frequently, for example when scheduling each transmission, but The generation and updating of the block quality estimates may be infrequent or even one-time. For example, link quality estimates may be generated only at installation time and not updated thereafter. In other embodiments, the link quality estimates are calculated every 3, 6, or 12 months, for example. when it detects a change in location or the success rate decreases (e.g., packet loss increases) However, in other embodiments, the link item may be generated or updated infrequently, such as when the link item is Quality estimation may be performed before each transmission or more frequently, including on-demand.

[0086] The method may use measurements or historical data or models, or may be based on a source or It may be performed solely by the terminal using feedback information from the intended recipient. Alternatively, it may be implemented using distributed computing. Alternatively, the estimation may be performed independently of the terminal and provided to the terminal. Estimating link quality estimates or thresholds for determining update or transmission parameters The parameters used for the determination may be transmitted or uploaded to the terminal.

[0087] Various embodiments are configured to reduce battery consumption and extend battery life. In some embodiments, the estimation is performed infrequently, for example to help conserve battery life. In some embodiments, a small number of measurements can be combined to produce an accurate estimate (or update). (new) can be obtained from the history database and / or stored information such as models In some embodiments, the method may be distributed or multi-system. The method uses information from system entities, e.g., in representing spatial summaries. It minimizes the amount of data required, saving power when transferring information in a distributed system. Furthermore, the estimates maximize the probability of reception and reduce the need for retransmissions. , can be used to select transmission parameters. If there is high reliability of the link, it may be possible to reduce the transmit power.

[0088] Those skilled in the art will appreciate that information and signals may be transmitted using any of a variety of technologies and techniques. For example, it will be understood that the various And there is data, instructions, commands, information, signals, bits, symbols, and chips, voltage, Electric current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any of these It may be represented by a combination.

[0089] Those skilled in the art will further appreciate that the various exemplary embodiments described in connection with the embodiments disclosed herein may be readily understood. Logic blocks, modules, circuits, and algorithm steps are electronic hardware embodied as computer software or instructions, or a combination of both This interchangeability of hardware and software is clearly For clarity of illustration, various illustrative components, blocks, modules, circuits, and steps may be used. Hardware has been generally described above in terms of its functionality. Whether it is implemented as hardware or software, it is given to the entire system. It depends on the particular application and design constraints. Those skilled in the art will be able to adapt the described functionality to their particular application. The present invention may be implemented in various ways for each application, and the implementation decisions are not within the scope of the present invention. This should not be construed as resulting in any deviation from the scope of the present invention.

[0090] The steps of a method or algorithm described in connection with the embodiments disclosed herein A processor is a software module that is executed by a processor in the form of hardware. The present invention may be embodied directly in the form of a hardware implementation, or in the form of a combination of the two. In this case, the processing may be performed by one or more application specific integrated circuits (ASICs), digital signal processors, or Digital Signal Processors (DSP), Programmable Logic Devices (PL D), Field Programmable Gate Array (FPGA), Processor, Controller controllers, microcontrollers, microprocessors, and other devices that perform the functions described herein. may be realized in other electronic units designed to stomach.

[0091] In some embodiments, the processor module 120 may perform some of the steps of the method. and one or more central processing units (CPUs) configured to perform the following: Similarly, a computing device may be used to generate a trajectory model that is provided to a terminal device. The computing device may include one or more CPUs. U is an input / output interface, an arithmetic logic unit (ALU), and an input / output interface a control unit and a program counter element communicating with an input / output device through the The input / output interface may be a standard communication protocol (e.g., Bluetooth oth, Zigbee, IEEE 802.15, IEEE 802.11, TCP / I P, UDP, etc.) to communicate with an equivalent communication module in another device; It may also include a network interface and / or a communication module. The computing or terminal device may have a single CPU (core) or multiple CPUs (multi-core ), or multiple processors. Parallel processors, vector processors may be used, or cloud-based Distributed computing devices, including computing devices and resources The memory may be operatively coupled to the processor and may include RAM and ROM. may comprise a component within a device or processor module or The memory may be provided externally. The memory may contain the operating system and additional software. The memory may be used to store software modules or instructions. may be configured to load and execute stored software modules or instructions good.

[0092] A software module is a computer program, computer code, or Also known as instructions, they are a number of source code or object code segments. It may contain RAM memory, Flash memory, ROM memory, E PROM memory, registers, hard disk, removable disk, CD-ROM , DVD-ROM, Blu-ray Disc, or any other form of computer readable medium The program may reside in any computer readable medium, such as a computer Data-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, in other aspects, the computer-readable medium may be a transitory computer-readable Combinations of the above may also include computer-readable media. In another aspect, the computer-readable medium comprises a processor and The processor and the computer-readable medium may be integrated into an ASIC or related device. The software code may be stored in a memory unit. , the processor may be configured to execute them. The implementation may be implemented within the processor or outside the processor, and if outside the processor, may be implemented using techniques known in the art. The device may be communicatively coupled to the processor via various means such as:

[0093] Additionally, modules and / or By other suitable means, downloaded and / or otherwise transmitted by a computing device It should be appreciated that such devices may be obtained by, for example, connecting such devices to a server. , can facilitate the transfer of means for performing the methods described herein; or The various methods described herein may be implemented using storage means (e.g., RAM, ROM, compact disk, etc.). Provided via physical storage media such as CDs or floppy disks whereby the computing device may have a storage means coupled to the device. In addition, various methods can be used to provide the Any other suitable technique for providing the methods and techniques may be utilized.

[0094] The methods disclosed herein may comprise one or more steps or methods for achieving the described method. The method steps and / or actions may deviate from the scope of the claims. In other words, certain steps or actions may be interchanged without modification. Unless an order is specified, the order and / or sequence of specific steps and / or actions is not mandatory. The specification may be modified without departing from the scope of the claims.

[0095] As used herein, the terms "estimating" or "determining" refer to a wide variety of actions. For example, "estimating" or "determining" includes calculating, computing, processing, Deriving, examining, or searching (e.g., searching a table, database, or other data structure) , confirming, etc. Also, "estimating" or "determining" may include receiving (e.g., receiving information), evaluating (e.g., evaluating data in memory), etc. Also, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0096] It should be understood that the present disclosure is not limited in its use to one or more of the particular applications described. Those skilled in the art will recognize that the present disclosure does not incorporate any specific features described or illustrated herein. The present disclosure is not limited to its preferred embodiments with respect to elements and / or features. The present invention is not limited to any one or more embodiments described and defined by the following claims. Numerous rearrangements, modifications, and substitutions are possible without departing from the scope as set forth. As used herein, "at least one" of a series of items refers to The phrases about refer to any combination of those items, including the singular. , b, or c" means a, b, c, a and b, a and c, b and c, and a and b and c.

[0097] Throughout the specification and the following claims, unless the context otherwise requires: The words "comprise" and "include," as well as "comprise" and "include" Any variation includes the integer or groups of integers presented, but does not include any other integer or groups of integers. It is understood to imply that it is not excluded.

[0098] Any reference to prior art in this specification is without prejudice to the fact that such prior art is part of the common general knowledge. is not, and shall not be construed as, an endorsement of any proposal to form It shouldn't be.

[0099] It should be understood that the present disclosure is not limited in its use to one or more of the particular applications described. Those skilled in the art will recognize that the present disclosure does not incorporate any specific features described or illustrated herein. The present disclosure is not limited to its preferred embodiments with respect to elements and / or features. The present invention is not limited to any one or more embodiments described and defined by the following claims. Numerous rearrangements, modifications, and substitutions are possible without departing from the scope as set forth. It will be recognized that.

Claims

1. 1. A method for determining the location and / or orientation of a terminal in a satellite communications system comprising a plurality of terminals and a plurality of access nodes, the access nodes comprising one or more satellite access nodes; The method comprises: monitoring, at the installation site, a plurality of transmission links from a plurality of transmitters, the plurality of transmitters comprising a plurality of satellite or aircraft transmitters moving relative to the installation site, the plurality of transmitters being either access nodes in a satellite communications system or transmitters in another system; determining a skyview map representation of link quality at the installation location by dividing the sky into a plurality of spatial regions, each spatial region comprising a range of azimuth and elevation coordinates, monitoring a plurality of transmission links to obtain a plurality of link quality estimates, estimating a spatial location for each of the plurality of link quality estimates, the spatial location being an estimate of the azimuth and elevation angle of the associated transmitter relative to the installation location at the time of transmission, and for each spatial region, combining the link quality estimates with their spatial locations within the respective spatial region to obtain a spatially aggregated link quality estimate, wherein the skyview map consists of a polar coordinate plot centered on the installation location, with rotation and radius indicating link quality versus azimuth and elevation coordinates, respectively, or an equivalent parametric representation of the skyview map constructed using a distribution on a sphere or a superposition of distributions; the skyview map is constructed from a polar plot centered on the installation location, with rotation and radius indicating link quality versus azimuth and elevation coordinates, respectively, or an equivalent parametric representation of a skyview map constructed using a spherical distribution or a superposition of distributions; and using the skyview map representation of link quality to determine one or both of a location and an orientation of a terminal in the satellite communications system and to locate the terminal.

2. The method of claim 1 , wherein the plurality of transmitters comprises at least one access node of a satellite communications system and at least one transmitter of another system.

3. The method comprises: storing, by the terminal, the sky-view map representation; In use, the terminal uses the skyview map to determine one or more transmission parameters for a transmission from the terminal to an access node; the one or more transmission parameters comprise one or more of a duration, a data rate, a power, a frequency, and a plurality of transmission times for repeatedly transmitting the transmission; The method according to claim 1 or 2.

4. The method described in claim 3, wherein the spatially aggregated link quality estimates of the skyview map are used to estimate the probability of success or failure of a transmission, and multiple transmission times for repeatedly transmitting a transmission are selected to maximize the probability that the terminal will successfully receive the transmission at the access node.

5. The method according to claim 3 or 4, wherein the monitoring of the plurality of transmission links and the determination of the sky-view map representation are performed by a device external to the terminal in which it is installed, and the sky-view map representation is provided to the terminal.

6. determining at least one of one or more link quality estimates; 6. The method of claim 1, further comprising: determining, by the terminal, a link quality estimate based on an expected received signal strength for a transmission from one of the senders to the terminal via the send link, the expected received signal strength being estimated using estimates of a send link sender power, a sender antenna gain, a receiver antenna gain, and a propagation loss based on an estimate of a link distance between the terminal and the sender.

7. determining at least one of one or more link quality estimates; determining an expected received signal strength for a transmission from the transmitter to a receiver at the installation location, the expected received signal strength being estimated using estimates of transmitter power, receiver gain, and path loss based on an estimate of link distance; obtaining an estimate of the received signal strength observed at the receiver; and and estimating a link quality estimate based on a difference between the expected received signal strength and the observed received signal strength.

8. determining at least one of one or more link quality estimates; determining a spatially relative link quality estimate obtained by comparing one or more parameters of a transmission link between the terminal and a sender for a plurality of positions of the sender, such that the estimation of link quality does not require knowledge of transmission power or antenna characteristics; 6. The method according to any one of claims 1 to 5.

9. The method of claim 1 , wherein combining a plurality of link quality estimates comprises combining a plurality of link quality estimates over a historical period.

10. The step of determining a skyview map representation of link quality includes: distributed between the terminal and each of one or more system access nodes that provide feedback information to the terminal; the feedback information is one or more of a performance metric, an acknowledgment rate, or an average packet success used by the terminal to determine the skyview map representation, or the feedback information is a skyview map representation.

5. The method according to any one of claims 1 to 4.

11. monitoring the plurality of transmission links at an installation location, performing measurements of a plurality of received signal strength measurements from the plurality of transmitters at the installation location; The step of determining a skyview map representation of link quality includes: and providing a plurality of measurements of the received signal strength as input to a model configured to output a skyview map representation based on the plurality of measurements.

12. at least one transmitter of the other system includes one or more Global Navigation Satellite System (GNSS) satellites; The method of claim 11 , further comprising determining the position of a GNSS satellite for each measurement of received signal strength from the GNSS satellite.

13. the measurements are performed by the terminal; The determining of the skyview map representation is performed by the terminal; The method further includes storing the skyview map representation by the terminal; 12. The method of claim 11, wherein, during use, the terminal uses the sky view map to determine one or more transmission parameters for a transmission from the terminal to the access node, the one or more transmission parameters consisting of one or more of a duration, a data rate, a power, a frequency, and a plurality of transmission times for repeatedly transmitting a transmission.

14. The method of claim 11 , wherein the measurements are performed by a device external to the terminal in question.

15. The method of claim 14 , wherein the determination of the skyview map representation is performed by a device external to the terminal in which it is installed.

16. The method further includes providing a skyview map representation to the terminal in use; 16. The method of claim 15, wherein the terminal uses the sky view map to determine one or more transmission parameters for a transmission from the terminal to an access node, the one or more transmission parameters consisting of one or more of a duration, a data rate, a power, a frequency, and a plurality of transmit times for repeatedly transmitting a transmission.

17. A method as described in claim 13 or 16, wherein the spatially aggregated link quality estimates of the skyview map are used to estimate the probability of success or failure of a transmission, and multiple transmission times for repeatedly transmitting the transmission are selected to maximize the probability of successful reception of the transmission by the terminal to the access node.

18. at least one transmitter of the other system includes one or more Global Navigation Satellite System (GNSS) satellites; The method of claim 15 , further comprising determining the position of a GNSS satellite for each measurement of received signal strength from the GNSS satellite.

19. at least one transmitter in the other system includes one or more Global Navigation Satellite System (GNSS) satellites; The method of claim 1 , wherein monitoring a plurality of transmission links from a plurality of transmitters comprises monitoring one or more transmissions from one or more of the GNSS satellites.

20. 1. An apparatus comprising an antenna, communications hardware, a processor, and a memory containing instructions that configure the processor to: monitoring, at an installation site, a plurality of transmission links from a plurality of transmitters, the plurality of transmitters comprising a plurality of satellite transmitters or aircraft transmitters moving relative to the installation site, the plurality of transmitters being either access nodes in a satellite communications system including a plurality of terminal devices and a plurality of access nodes, the access nodes comprising one or more satellite access nodes or transmitters in another system; Dividing the sky into a plurality of spatial regions, each spatial region comprising a range of azimuth and elevation coordinates, monitoring a plurality of transmission links to obtain a plurality of link quality estimates, estimating a spatial location for each of the plurality of link quality estimates, the spatial location being an estimate of the azimuth and elevation angle of the associated transmitter relative to the installation location at the time of transmission, and for each spatial region, combining the link quality estimates with their spatial locations within the respective spatial region to obtain a spatially aggregated link quality estimate, thereby determining a skyview map representation of the link quality at the installation location, the skyview map consisting of a polar coordinate plot centered on the installation location, with rotation and radius indicating the link quality with respect to the azimuth and elevation coordinates, respectively, or an equivalent parametric representation of the skyview map constructed using a distribution on a sphere or a superposition of distributions; In use, the skyview map representation of link quality is used to determine one or both of the location and orientation of the terminal device in a satellite communications system.

21. 21. The apparatus of claim 20, wherein the plurality of transmitters comprises at least one access node of the satellite communications system and at least one transmitter of another system.

22. providing the skyview map representation to a terminal device within the satellite communications system; 22. The apparatus of claim 20 or 21, wherein, in use, the terminal device uses the sky view map to determine one or more transmission parameters for transmissions from the terminal device to an access node in a satellite communications system, the one or more transmission parameters consisting of one or more of duration, data rate, power, frequency, and multiple transmission times for repeatedly transmitting a transmission.

23. The apparatus described in claim 22, wherein the spatially aggregated link quality estimates of the skyview map are used to estimate the probability of success or failure of a transmission, and multiple transmission times for repeatedly sending a transmission are selected to maximize the probability that the terminal will successfully receive the transmission at the access node.

24. 24. The device according to claim 22 or 23, wherein the device is a terminal device in the satellite communication system.

25. the device is a terminal device in the satellite communications system, and determining at least one of the one or more link quality estimates comprises: determining, by the terminal device, a link quality estimate based on an expected received signal strength for a transmission from one of the senders over a transmit link to the terminal device; 24. The apparatus of claim 20, wherein the expected received signal strength is estimated using estimates of transmit link transmitter power, transmitter antenna gain, receiver antenna gain, and path loss based on an estimate of a link distance between the terminal device and the transmitter.

26. the device is a terminal device in the satellite communications system, and determining at least one of the one or more link quality estimates comprises:

24. The apparatus of claim 20, comprising determining a spatially relative link quality estimate obtained by comparing one or more parameters of a transmission link between a terminal and a sender for multiple positions of the sender, such that the estimation of link quality does not require knowledge of transmit power or antenna characteristics.

27. 25. The apparatus of claim 20, wherein combining a plurality of link quality estimates comprises combining a plurality of link quality estimates over a past period of time.

28. the device is a terminal device in the satellite communication system, The step of determining a skyview map representation of link quality includes: distributed between the terminal device and each of one or more system access nodes that provide feedback information to the terminal; 24. The apparatus of claim 20, wherein the feedback information is one or more of a performance metric, an acknowledgement rate, or an average packet success used by the terminal to determine the sky-view map representation, or the feedback information is a sky-view map representation.

29. Monitoring the plurality of transmission links at the installation location comprises: performing, with the device, a plurality of measurements of received signal strength from a plurality of transmitters at the installation location; determining the skyview map representation of link quality, 22. The apparatus of claim 20 or 21, comprising providing a plurality of measurements of received signal strength as input to a model configured to output a skyview map representation based on the plurality of measurements.

30. at least one transmitter of the other system comprises one or more Global Navigation Satellite System (GNSS) satellites; 30. The apparatus of claim 29, wherein the processor is further configured to determine a position of a GNSS satellite for each measurement of received signal strength from the GNSS satellite.

31. the device is further configured to provide a skyview map representation to one of the plurality of terminal devices in the satellite communications system; 30. The apparatus of claim 29, wherein, during use, the terminal device uses the sky view map to determine one or more transmission parameters for a transmission from the terminal device to an access node, the one or more transmission parameters consisting of one or more of a duration, a data rate, a power, a frequency, and a plurality of transmission times for repeatedly transmitting a transmission.

32. The apparatus of claim 31, wherein the spatially aggregated link quality estimates of the skyview map are used to estimate the probability of success or failure of a transmission, and multiple transmission times for repeatedly transmitting a transmission are selected to maximize the probability that the terminal will successfully receive the transmission at the access node.

33. 24. The apparatus of any one of claims 20 to 23, wherein at least one transmitter of the other system comprises one or more Global Navigation Satellite System (GNSS) satellites, and wherein monitoring multiple transmission links from the multiple transmitters comprises monitoring one or more transmissions from one or more satellites of the Global Navigation Satellite System (GNSS).

34. 10. A computer-readable medium containing instructions that cause a processor to perform the method of claim 1.

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