Patent ID: 12255730

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result. Moreover, some of the method steps can be carried serially or in parallel, or in any order unless specifically expressed or understood in the context of other method steps.

FIG.1schematically shows an embodiment of a test system10. In general, the test system10is configured to assess the performance of a user equipment (UE) device12that is configured to communicate with a non-terrestrial network (NTN). Accordingly, the test system10may be established as a mobile communication tester, i.e., the UE device12may be a mobile communication device.

For example, the UE device12may be established as any electronic device that is capable of communicating with a non-terrestrial network, for example via 5G. For example, the UE device12may be a mobile phone, a smartphone, a tablet, a laptop, a ground node, a vehicle infotainment system, etc.

Accordingly, the terms “uplink signal”, “downlink signal”, “PRACH”, etc. used in the following may relate to corresponding signals within a 5G framework.

The test system10comprises, for example, a control circuit14, a signal generator16comprising a signal generating circuit, at least one antenna array18, an analysis circuit20, and a positioner22. In general, the control circuit14is configured to control the signal generator16, the analysis circuit20, and/or the positioner22, as will be described in more detail below.

For example, the control circuit14may be established as a computing device with suitable software being executed on the computing device. For example, the control circuit14may be established as a personal computer, a MAC, a smartphone, or as another type of smart device with suitable software. Likewise, the analysis circuit20may be established as a computing device with suitable software being executed on the computing device. For example, the analysis circuit20may be established as a measurement instrument, such as an oscilloscope, for example a digital oscilloscope, a spectrum analyzer, or as a signal analyzer. However, the analysis circuit20may also be a personal computer, a MAC, a smartphone, or another type of smart device with suitable software. It is noted that the analysis circuit20and the control circuit14may also be integrated into a single electronic device.

The positioner22is configured to adapt a relative position between the antenna array18and the UE device12. Accordingly, the positioner22may comprise a holder that is configured to hold the UE device at a desired location with a desired orientation.

Further, the positioner22may comprise positioning means that are configured to adapt a location and/or orientation of the UE device12. For example, the positioner22may comprise a linear positioner that is configured to adapt the location of the UE device12and/or a rotational positioner that is configured to adapt the orientation of the UE device12, for example a revolving table. For example, the positioner22in some embodiments may include one or more linear and/or rotary stages.

Alternatively or additionally, the positioner22may comprise positioning means that are configured to adapt a location and/or orientation of the antenna array18. For example, the positioner22may comprise a linear positioner that is configured to adapt the location of the antenna array18and/or a rotational positioner that is configured to adapt the orientation of the antenna array18, for example a revolving table.

In either arrangement, the positioner22in some embodiments may include one or more linear and/or rotary stages.

The signal generator16is configured to generate RF signals and to forward the generated RF signals to the antenna array18for transmission. For example, the signal generator16may be established as an arbitrary waveform generator or as any other type of suitable signal generator.

The antenna array18is configured to transmit the RF signals generated by the signal generator16by forming suitable beams in one or several directions, wherein the power and/or physical cell ID (PCI) associated with the beams may be varied appropriately. Further, the antenna array18is configured to receive RF signals, for example from the UE device12.

The analysis circuit20is connected to the antenna array18in a signal-transmitting manner, such that RF signals received by the antenna array18are forwarded to the analysis circuit20for further analysis.

Therein and in the following, the term “connected in a signal transmitting manner” is understood to denote a cable-based or wireless connection that is configured to transmit signals between the respective devices or components.

The control circuit14is configured to control the test system10to perform a method of testing user equipment for non-terrestrial networks, an example of which is described in the following with reference toFIG.2.

A downlink signal comprising GNSS data and ephemeris data is generated by the signal generator16(step S1).

As is illustrated inFIG.3, the GNSS data is associated with a position of the UE device12. For example, the GNSS data may correspond to the actual position of the UE device12on the surface24of earth or to an emulated position of the UE device12on the surface24of earth. In other words, the test system10or rather the signal generator16may emulate an arbitrary position of the UE device12by synthesizing appropriate GNSS data.

The ephemeris data corresponds to the ephemeris data of a satellite node26that is emulated by the test system10. In other words, the ephemeris data may not correspond to an actually existing satellite node, but rather to the satellite node26emulated by the test system10. The satellite node26may also be referred to as “NTN-gNB”.

Accordingly, the downlink signal generated by the test system10comprises information at least on the position of the UE device12and on the position of the emulated satellite node26.

However, as is further illustrated inFIG.3, the downlink signal may further comprise information on a relative velocity v of the satellite node26and the UE device12.

In other words, the test system10is configured to emulate a trajectory of the satellite node26in its orbit around earth.

The relative velocity between the satellite node26and the UE device12stems from the movement of the satellite node26in its orbit around earth and/or from a movement of the UE device12on the surface24of the earth.

For example, the orbit of the satellite node26may correspond to a low earth orbit trajectory, i.e., to the trajectory of a satellite in about 700 km to 1500 km height. However, it is to be understood that the orbit may be any other orbit, for example to any other stable orbit.

Without restriction of generality, it is assumed in the following that the UE device12is not moving with respect to the surface24of the earth, such that the relative velocity between the satellite node26and the UE device12is due the movement of the emulated satellite node26in its orbit.

In order to emulate the relative velocity between the satellite node26and the UE device12, the downlink signal may be Doppler-shifted appropriately. The Doppler-shift depends on a velocity component of the satellite node26in the direction of a connecting axis between the UE device12and the satellite node26. Thus, the Doppler-shift is dependent on a relative position between the UE device12and the satellite node26.

For example, the Doppler-shift may have the functional form28qualitatively illustrated inFIG.3. The magnitude of the Doppler-shift becomes higher the further the satellite node26is away from a position in the zenith over the UE device12. The magnitude of the Doppler shift is lowest, for example zero, if the satellite node26is in the zenith over the UE device12. In other words, the Doppler-shift is lowest if the UE device12is in the nadir of the satellite node26.

The Doppler-shifted downlink signal may comprise a synchronization signal block (SSB). The SSB may be employed by the UE device12in order to synchronize to a carrier frequency, for example to a carrier frequency associated with the downlink signal. Thus, it is ensured that the UE device12can correctly determine the Doppler-shift applied to the downlink signal.

Alternatively or additionally, the downlink signal may comprise a power control command. The power control command may comprise instructions for the UE device12to enter a certain operational mode, for example a standby mode, a receiver mode, and/or a transmitter mode.

The (Doppler-shifted) downlink signal is transmitted to the UE device12by the antenna array18(step S2).

The UE device12processes the received downlink signal and determines a timing advance and/or a Doppler pre-compensation shift based on the received downlink signal (step S3).

For example, the UE device12determines the timing advance and/or the Doppler pre-compensation shift based on the GNSS data and the ephemeris data provided via the downlink signal. Optionally, the UE device12may determine the Doppler pre-compensation shift based on the Doppler-shift of the downlink signal.

Therein, the timing advance corresponds to an adjustment of the sending time of uplink signals in order to compensate a propagation delay between the UE device12and the satellite node26, as is well known in the field of mobile communication, for example within the 4G or 5G framework.

Moreover, the Doppler pre-compensation shift corresponds to a Doppler shift that is necessary to counteract the Doppler shift induced by the relative velocity between the satellite node26and the UE device12.

The necessary timing advance and the necessary Doppler pre-compensation shift depend on the distance, the angle, and the relative velocity between the UE device12and the satellite node26.

The UE device12may determine the distance d, the angle α, and the relative velocity vrelbetween the UE device12and the satellite node26based on the GNSS data and the ephemeris data, as is illustrated inFIG.4.

In some examples, the UE device12may determine the distance according to the formula
d=√{square root over (RE2sin2α+h02+2h0RE)}−REsin α

wherein REis the radius of earth, h0is the height of the satellite node26above the surface24of the earth, and α is the angle between the satellite node26, the UE device12, and the horizon from the point of view of the UE device12.

A first uplink signal is generated by the UE device12based on the determined timing advance and/or based on the determined Doppler pre-compensation shift (step S4).

The first uplink signal may correspond to a request for an uplink allocation from the satellite node26. Thus, the first uplink signal may be associated with a Physical Random Access Channel (PRACH). In other words, the first uplink signal may be part of a cell acquisition procedure initiated by the UE device12.

The first uplink signal is transmitted to the antenna array18, received by the antenna array18, and forwarded to the analysis circuit20. The first uplink signal is analyzed by the analysis circuit20in order to assess a performance of the UE device12(step S5).

Therein and in the following, the term “analyzing an uplink signal” is understood to denote analyzing the content of the uplink signal and/or analyzing properties of the uplink signal, such as a time of receipt, a frequency content, a power, a bandwidth etc.

In general, the analysis circuit20assesses whether a correct timing advance and/or a correct Doppler pre-compensation shift has been applied to the uplink signal by the UE device12in view of the provided GNSS data and in view of the provided ephemeris data.

In order to assess whether the correct timing advance has been applied, the analysis circuit20may determine an expected time window based on the GNSS data and the ephemeris data.

As is illustrated inFIG.5, the expected time window may be an expected PRACH occasion window30, i.e., a time window in which the receipt of an uplink allocation request sent by the UE device12is expected with respect to a reference time Tref, for example wherein the reference time Trefmay correspond to the time of sending the downlink signal.

Alternatively or additionally, the expected time window corresponds to an expected round-trip time, i.e., a time between sending the downlink signal and receiving the corresponding uplink signal. The expected round trip time may have allowed error margins, such that the expected round-trip time corresponds to a round-trip time interval rather than to a single value.

The analysis circuit20is aware of the GNSS data and the ephemeris data provided to the UE device12, i.e., of the emulated position of the UE device12and of the emulated position of the satellite node26. Thus, the analysis circuit20can correctly determine the expected time window.

If the uplink signal is received within the expected time window, it can be concluded that the UE device12has determined the timing advance correctly.

If, however, the uplink signal is received outside of the expected time window at a time32later or earlier than the expected time window, it can be concluded that the UE device12has determined the timing advance incorrectly, which may be an indication for a malfunction of the UE device12.

In order to assess whether a correct Doppler pre-compensation shift has been applied to the uplink signal by the UE device12, the analysis circuit20may determine an expected Doppler pre-compensation shift based on the GNSS data and the ephemeris data, and optionally based on the Doppler-shift applied to the downlink signal. In an embodiment, the expected Doppler pre-compensation shift may correspond to an expected frequency window.

Accordingly, if the Doppler pre-compensation shift applied to the uplink signal or the frequency of the uplink signal itself is within the expected frequency window, it can be concluded that the UE device12has determined the Doppler pre-compensation shift correctly.

If, however, the Doppler pre-compensation shift applied to the uplink signal or the uplink signal itself is outside of the expected frequency window, it can be concluded that the UE device12has determined the Doppler pre-compensation shift incorrectly, which may be an indication for a malfunction of the UE device12.

Once a communication is established between the emulated satellite node26and the UE device12, the test system10may generate and transmit further downlink signals in order to continue the assessment of the performance of the UE device12(step S6).

In some examples, the test system10may provide time-variant GNSS data to the UE device12by the further downlink signals, wherein the time-variant data resembles a movement of the UE device12. In other words, while the UE device12may remain stationary within the test system10, the test system10provides time-variant GNSS data such that the UE device12“thinks” it is moving.

Moreover, a Doppler-shift applied to the downlink signals may be time-variant, such that the change of the relative velocity between the UE device12and satellite node26over the course of the trajectory of the satellite node26is correctly emulated.

The UE device12processes the further downlink signals and determines a time-variant timing advance and/or a time-variant Doppler pre-compensation shift based on the further downlink signals (step S7).

However, it is also conceivable that the UE device12determines the time-variant timing advance and/or a time-variant Doppler pre-compensation shift based on the first downlink signal provided by the test system10.

The test system10may emulate the (time-variant) distance between the UE device12and the satellite node26by adding an appropriate (time-variant) delay to the downlink signals, wherein the delay corresponds to the emulated (time-variant) distance between the UE device12and the satellite node26.

A plurality of uplink signals is generated by the UE device12over a predetermined time period, wherein the plurality of uplink signals is analyzed by the analysis circuit20in order to assess the performance of the UE device12(step S8).

Thus, the analysis circuit20may assess whether the UE device12correctly applies the time-variant timing advance and/or the time-variant Doppler pre-compensation shift to the plurality of uplink signals. In other words, the analysis circuit20determines whether the UE device12functions correctly under time-variant conditions, namely a time-variant distance, angle and speed relative to the satellite node26.

As is illustrated inFIG.6, the predetermined time period may correspond to the duration of a connection between the satellite node26and the UE device12. In other words, the predetermined time period may correspond to the time interval spanning from a connection setup between the UE device12and the emulated satellite node26to a connection termination.

Step S8may be performed essentially analogous to steps S4and S5described above. However, the expected time window and/or the expected Doppler pre-compensation shift may be time-variant as well, as the expected round-trip time (“RTT” inFIG.6) varies over time as well.

For example, the expected round-trip time RTTinitat connection setup and the expected round-trip time RTTexitat connection termination are longer than to the expected round-trip time RTTnadirwhen the UE device12is in the nadir of the simulated satellite node26.

In some examples, the plurality of uplink signals may correspond to a plurality of data signals instead of an uplink allocation request. Thus, the plurality of uplink signals may correspond to data signals comprising data packets to be transmitted to the satellite node26.

Accordingly, the analysis circuit20may determine a data rate and/or a data throughput associated with the uplink signals in order to assess the performance of the UE device12. Optionally, the test system10or the signal generator16may emulate an atmospheric and terrestrial fading profile. Accordingly, additional perturbations that may occur in the atmosphere during transmission of the downlink signal and/or during the transmission of the uplink signal(s) may be emulated by the test system10. Thus, the interference immunity of the UE device may be assessed by the analysis circuit20by analyzing the uplink signal(s) generated by the UE device12.

Certain embodiments disclosed herein utilize circuitry (e.g., one or more circuits) in order to implement standards, protocols, methodologies or technologies disclosed herein, operably couple two or more components, generate information, process information, analyze information, generate signals, encode/decode signals, convert signals, transmit and/or receive signals, control other devices, etc. Circuitry of any type can be used. It will be appreciated that the term “information” can be use synonymously with the term “signals” in this paragraph. It will be further appreciated that the terms “circuitry,” “circuit,” “one or more circuits,” etc., can be used synonymously herein.

In an embodiment, circuitry includes, among other things, one or more computing devices such as a processor (e.g., a microprocessor), a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system on a chip (SoC), or the like, or any combinations thereof, and can include discrete digital or analog circuit elements or electronics, or combinations thereof.

In an embodiment, circuitry includes hardware circuit implementations (e.g., implementations in analog circuitry, implementations in digital circuitry, and the like, and combinations thereof). In an embodiment, circuitry includes combinations of circuits and computer program products having software or firmware instructions stored on one or more computer readable memories that work together to cause a device to perform one or more protocols, methodologies or technologies described herein. In an embodiment, circuitry includes circuits, such as, for example, microprocessors or portions of microprocessor, that require software, firmware, and the like for operation. In an embodiment, circuitry includes an implementation comprising one or more processors or portions thereof and accompanying software, firmware, hardware, and the like. In some embodiments, the functionality described herein can be implemented by special purpose hardware-based computer systems or circuits, etc., or combinations of special purpose hardware and computer instructions.

Various embodiments of the present disclosure or the functionality thereof may be implemented in various ways, including as non-transitory computer program products. A computer program product may include a non-transitory computer-readable storage medium storing applications, programs, program modules, scripts, source code, program code, object code, byte code, compiled code, interpreted code, machine code, executable instructions, and/or the like (also referred to herein as executable instructions, instructions for execution, program code, computer program instructions, and/or similar terms used herein interchangeably). Such non-transitory computer-readable storage media include all computer-readable media (including volatile and non-volatile media).

Embodiments of the present disclosure may also take the form of an apparatus, system, computing device, computing entity, and/or the like executing instructions stored on computer-readable storage media to perform certain steps or operations. The computer-readable media include cooperating or interconnected computer-readable media, which exist exclusively on a processing or processor system or distributed among multiple interconnected processing or processor systems that may be local to, or remote from, the processing or processor system. However, embodiments of the present disclosure may also take the form of an entirely hardware embodiment performing certain steps or operations.

Various embodiments are described above with reference to block diagrams and/or flowchart illustrations of apparatuses, methods, systems, and/or computer program instructions or program products. It should be understood that each block of any of the block diagrams and/or flowchart illustrations, respectively, of portions thereof, may be implemented in part by computer program instructions, e.g., as logical steps or operations executing on one or more computing devices. These computer program instructions may be loaded onto one or more computer or computing devices, such as special purpose computer(s) or computing device(s) or other programmable data processing apparatus(es) to produce a specifically-configured machine, such that the instructions which execute on one or more computer or computing devices or other programmable data processing apparatus implement the functions specified in the flowchart block or blocks and/or carry out the methods described herein.

These computer program instructions may also be stored in one or more computer-readable memory or portions thereof, such as the computer-readable storage media described above, that can direct one or more computers or computing devices or other programmable data processing apparatus(es) to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including computer-readable instructions for implementing the functionality specified in the flowchart block or blocks.

The computer program instructions may also be loaded onto one or more computers or computing devices or other programmable data processing apparatus(es) to cause a series of operational steps to be performed on the one or more computers or computing devices or other programmable data processing apparatus(es) to produce a computer-implemented process such that the instructions that execute on the one or more computers or computing devices or other programmable data processing apparatus(es) provide operations for implementing the functions specified in the flowchart block or blocks and/or carry out the methods described herein.

It will be appreciated that the term computer or computing device can include, for example, any computing device or processing structure, including but not limited to a processor (e.g., a microprocessor), a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system on a chip (SoC), or the like, or any combinations thereof.

Accordingly, blocks of the block diagrams and/or flowchart illustrations support various combinations for performing the specified functions, combinations of operations for performing the specified functions and program instructions for performing the specified functions. Again, it should also be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, or portions thereof, could be implemented by special purpose hardware-based computer systems or circuits, etc., that perform the specified functions or operations, or combinations of special purpose hardware and computer instructions.

In the foregoing description, specific details are set forth to provide a thorough understanding of representative embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that the embodiments disclosed herein may be practiced without embodying all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.

Throughout this specification, terms of art may be used. These terms are to take on their ordinary meaning in the art from which they come, unless specifically defined herein or the context of their use would clearly suggest otherwise.

The present application may reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present application. Also in this regard, the present application may use the term “plurality” to reference a quantity or number. In this regard, the term “plurality” is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms “about,” “approximately,” “near,” etc., mean plus or minus 5% of the stated value. For the purposes of the present disclosure, the phrase “at least one of A and B” is equivalent to “A and/or B” or vice versa, namely “A” alone, “B” alone or “A and B.”. Similarly, the phrase “at least one of A, B, and C,” for example, means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed.

The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure, as claimed.