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WO2023134836A1 - Balise nb-iot non terrestre - Google Patents

Balise nb-iot non terrestre Download PDF

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Publication number
WO2023134836A1
WO2023134836A1 PCT/DK2023/050006 DK2023050006W WO2023134836A1 WO 2023134836 A1 WO2023134836 A1 WO 2023134836A1 DK 2023050006 W DK2023050006 W DK 2023050006W WO 2023134836 A1 WO2023134836 A1 WO 2023134836A1
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WIPO (PCT)
Prior art keywords
signal
beacon
transceiver device
communication system
beacon signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
PCT/DK2023/050006
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English (en)
Inventor
Henrik Krogh MØLLER
René Brandborg SØRENSEN
Bertel Kærgård BRANDER
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Gatehouse Satcom AS
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Gatehouse Satcom AS
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Publication of WO2023134836A1 publication Critical patent/WO2023134836A1/fr
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Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/18528—Satellite systems for providing two-way communications service to a network of fixed stations, i.e. fixed satellite service or very small aperture terminal [VSAT] system
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay
    • H04B7/18513—Transmission in a satellite or space-based system
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/70—Services for machine-to-machine communication [M2M] or machine type communication [MTC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/06—Airborne or Satellite Networks

Definitions

  • the present invention relates to a communication system comprising a base station, a transceiver device moving along a path at an altitude elevated from earth, and a UE located a position closer to the earth than the transceiver device.
  • the transceiver device is in data communication with the base station wherein the base station is either comprised in the transceiver device with the base station and the transceiver device configured to operate in a regenerative mode, or is located at a position away from the transceiver device with the base station and the transceiver device configured to operate in a transparent mode.
  • the invention resides inter alia in a concept of utilizing the spectral-temporal blocks that are unused in NB-IoT in standalone and guard-band operational mode for a beacon for quick, low-effort detection of the presence of a transceiver device such as a satellite base-station.
  • the cell search procedure is integral to establishing a connection between a Basestation (eNB - evolved Node B) and a User Equipment (UE) in NB-IoT Networks.
  • the cell search procedure is used to detect the presence of a cell when the UE either 1) must monitor for paging, 2) has data to transmit or 3) must initiate a procedural information exchange.
  • the cell search procedure in terrestrial NB-IoT was designed to be tolerant of very low SNR levels for UEs that were meant to be stationary (i.e., not changing cells). This latter point meaning that the time spent on cell search has been traded-off for signal-to-noise (SNR) tolerance.
  • SNR signal-to-noise
  • NTN non-terrestrial network
  • NGSO non-geostationary
  • a transceiver device moving along a path at an altitude elevated from earth and a UE located a position closer to the earth than the transceiver device, such as located at or on the earth, the transceiver device is in data communication with the base station wherein the base station is either o comprised in the transceiver device with the base station and the transceiver device configured to operate in a regenerative mode, or o is located at a position away from the transceiver device with the base station and the transceiver configured to operate in a transparent mode or in regenerative mode; wherein
  • the transceiver device (1) is configured for o transmitting information by modulating a signal on an anchor carrier and the signal comprising a number of sub frames, wherein one or more of the sub frames comprises a spectral-temporal block that is unused, o transmitting a beacon signal in one or more of said block(s)
  • the UE is configured for o detecting a beacon signal, and o performing a cell search if a beacon signal is detected.
  • the invention seeks to minimize the energy cost associated with the cell search procedure.
  • the cell search procedure may be used to adjust for any frequency offsets due to crystal offset or Doppler.
  • Regenerative mode refers to a regeneration of a received signal prior to retransmission.
  • Transparent mode refers to retransmission of a received signal.
  • the carrier is moved in frequency during the retransmission process.
  • the formulation "with the base station and the transceiver device configured to operate in a regenerative mode” and "with the base station and the transceiver device configured to operate in a transparent mode or regenerative mode” as used herein refer to that the transceiver device and base station are mutually configured to operate in one of the two modes, although the transceiver device may be considered as the element providing either a regeneration of a received signal or retransmission of received signal.
  • beacon signal is a signal modulated on an anchor carrier and used for detecting the presence of a cell.
  • the UE may use the beacon signal as a wake-up signal, and the beacon signal may in such embodiments be labelled a wake-up beacon signal.
  • NPSS Narrow Band Primary Synchronization Signal
  • Narrow Band Secondary Synchronization Signal is used as an abbreviation for Narrow Band Secondary Synchronization Signal.
  • Narrow Band Physical Broadcast Channel is used as an abbreviation for Narrow Band Physical Broadcast Channel.
  • PSS Primary Synchronization Signal
  • SSS Secondary Synchronization Signal
  • 4 spectral-temporal block that is unused preferably refers to a block that is allocated for the communication system, but not assigned to and used for any transmission. Such blocks include but are not limited to what commonly is referred to as "white spaces”. It worth noting that an unused spectral-temporal block that is used for transmission of the beacon remains an unused block from the perspective of unknowing participants in the network such as legacy UEs. Collisions are inherently avoided as white-spaces are not accessed by the unknowing participants, or the base-station coordinates the transmission in the otherwise unused spectral-temporal blocks.
  • Cell search as used herein may involve one or more, such as all of the following steps:
  • step 1 may be detection of the beacon signal, waking up the UE to perform one or more, such as all of the steps 2.-4.
  • the detection of the beacon signal in step 1 may yield coarse time and frequency information, which can be used in step 2 to speed up the legacy synchronisation process.
  • the UE may be configured for synchronization with the transceiver device during cell search subsequently to detecting a beacon signal.
  • the beacon transmission sequence may encode data by mapping bits to the state space spanned by possible frequency-, amplitude-, and timing-offsets of individual beacons or between sets of beacons.
  • cell-specific information such as cell ID, operator ID, access barring or similar may be encoded in the beacon sequence and utilized by UEs for preliminary assessment of the cell and potentially early discarding candidates cells.
  • the invention relates to a method of modulating an anchor carrier signal of a transceiver device to provide a beacon signal to a UE, the method comprising:
  • transceiver device • providing a transceiver device according to any the first aspect of the invention, o said transceiver device being configured to transmit information by modulating a signal on an anchor carrier and the signal comprising a number of sub frames, wherein one or more of the sub frames comprises a spectral-temporal block that is unused, o transmitting a beacon signal in one or more of said block(s)
  • the invention relates to a computer implemented method for modulating an anchor carrier signal of a transceiver device (1) to provide a beacon signal to a UE (2), the method comprising:
  • the present invention has been disclosed in connection with NB-IoT, but the invention is also applicable in relation to other non-terrestrial cellular technologies that have been adapted from terrestrial cellular technologies where resources may be made available for narrowband beacon signalling in the non-terrestrial network, for example NTN-LTE-M, NTN-LTE and NTN-NR.
  • the invention can be implemented by means of hardware, software, firmware or any combination of these.
  • the invention or some of the features thereof can also be implemented as software running on one or more data processors and/or digital signal processors.
  • the individual elements of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way such as in a single unit, in a plurality of units or as part of separate functional units.
  • the invention may be implemented in a single unit, or be both physically and functionally distributed between different units and processors.
  • Fig. 1 schematically illustrates a non-geo stationary satellite and a UE positioned on the earth.
  • Fig. 2 schematically illustrates a NB-IoT anchor carrier frame structure.
  • Fig. 3 schematically illustrates a repeated beacon signal.
  • Fig. 4 schematically illustrates an IQ-diagram for beacon signals.
  • Fig. 5 schematically illustrates a division of an anchor carrier into a set of detection channels.
  • Fig. 6 shows a flow-chart of method steps according to an embodiment of the invention.
  • Fig. 1 schematically illustrates a non-geo stationary satellite 1 and a UE 2 (user equipment) positioned on the earth 3.
  • the arrow shows the non-geostationary satellite travelling at a path P around the earth 3, covering an area on the earth 3, the area begin designated as a cell C, in which the UE 2 is enabled to optimally communicate with the non-geo stationary satellite 1.
  • Fig. 1 is not to scale.
  • the invention in Fig. 1 is disclosed in connection with a non-geo stationary satellite 1, and a stationary UE 2, the UE 2 may be non- stationary and/or the satellite 1 may be geo stationary. Further, the invention is not limited to satellites, as other high altitude device may be used instead or in combination with a satellite.
  • the device communicating with the UE 2 is typically referred herein to be a transceiver device moving along a path P at an altitude elevated from earth.
  • the UE 2 is preferably an loT device being configured to communicate with the satellite 1 in a narrow band.
  • the transceiver device establishes, typically by its antenna, a cell C within which a UE 2 can be in radio contact with the transceiver device, such as a satellite 1.
  • Fig. 2 schematically illustrates a NB-IoT anchor carrier frame structure 4.
  • signals used for cell search, along with other system information, are carried on what is known as an anchor carrier 4.
  • an anchor carrier 4 In stand-alone and guard-band mode of NB-IoT, a downlink frame today consists of ten sub frames SF#0 to SF#9 and on an anchor carrier 4 it will contain some blocks 5, 5' of unused spectrum (whitespaces) as depicted in Fig. 2. Such blocks 5, 5' of unused spectrum is also referred to herein as spectral-temporal blocks, that is unused.
  • the ninth sub frame SF#9 includes a spectral-temporal block 5' that is unused (whitespace) depending on whether the frame number is odd or even.
  • Each whitespace 5, 5' today lasts a period of 214.6 ps but other periods may be relevant for the present invention.
  • the invention resides inter alia in that the concept of utilizing the spectral- temporal blocks 5, 5' that are unused in NB-IoT synchronization signals and the NPBCH subframe SF#0 to SF#9 for a beacon for quick, low-effort detection of the presence of a transceiver device 1 such as a satellite base-station.
  • the narrowband beacon is in some embodiments a sine wave transmitted within an NB-IoT anchor carrier 4 at a known frequency.
  • Fig. 3 schematically illustrates a repeated beacon signal in a graph, wherein the x- axis represents time and the y-axis represents the amplitude of the signal and the z-axis represents frequency.
  • the left, lower sine wave shows a sine wave representing the transmitted beacon, as sent from a transceiver device, such as a satellite 1.
  • the upper left sine wave represents the beacon as received by the UE2, at a frequency and temporal offset relative to the transmission from the satellite 1.
  • the two sine waves on the right side of the graph represents a repeated beacon transmission and reception.
  • a communication system which comprises a base station and a transceiver device 1 moving along a path P at an altitude elevated from earth 3 and one or more UE's 2 located a position closer to the earth 3 than the transceiver device 1.
  • the UE's 2 do not need to be located at the surface of the earth 3 as they may be positioned at an elevated position relative to the surface of the earth 3, e.g. such as located at or on the earth 3.
  • the transceiver device 1 is in data communication with the base station wherein the base station is either comprised in the transceiver device with the base station and the transceiver device configured to operate in a regenerative mode, or is located at a position away from the transceiver device with the base station and the satellite is configured to operate in a transparent mode. In an alternative embodiment, the base station is located at a position away from the transceiver device with the base station and the transceiver device configured to operate in a regenerative mode.
  • the transceiver device such as a satellite 1, is configured for transmitting information by modulating a signal on an anchor carrier 4 and the signal comprising a number of sub frames SF#0 to SF#9, wherein one or more of the sub frames comprises a spectral-temporal block 5, 5' that is unused.
  • a spectral-temporal block 5, 5' that is unused.
  • the transceiver device is further configured to transmitting a beacon signal in one or more of the block(s) 5, 5'.
  • a beacon signal in one or more of the block(s) 5, 5'.
  • the term unused is used with reference to how the NB-IoT synchronization signal was designed namely to comprise such block 5, 5' not used for communication and by introducing a beacon signal in one or more of these blocks 5, 5' enables the block to be used for transmitting a beacon signal.
  • a block 5, 5' used for transmitting a beacon may alternatively be labelled "block containing a beacon signal".
  • a UE 2 is configured for detecting a beacon signal. How such a beacon can be detected will be disclosed in further details below.
  • a UE 2 is preferably also configured to performing a cell search for a cell C in which to optimally communicate, if a beacon signal is detected.
  • the UE 2 may be in what may be called a sleep mode, where the activity of the UE 2 preferably is limited to listen for a beacon and, if detected, the UE 2 wakes up, entering into an active mode where cell search is carried out. As the sleep mode requires substantially less electrical power than the active mode, the lifetime of e.g. a battery can be extended substantially.
  • the UE 2 contains information regarding an expected frequency of a beacon signal and a sequence in which such beacon signals are transmitted. Such information may advantageously be used in the search for beacons, as the search may be limited to a bandwidth including the expected frequency. Further, differences in expected frequency and received frequency may be used to determine a Doppler-shift.
  • the beacon is preferably transmitted in a 15kHz band, a 3.75kHz band or a more narrow band, which means the power density and therefore obtainable SNR is much greater than for the rest of the carrier.
  • the anchor carrier has some bandwidth (BW) allocated for modulation of information carrying signals, such as a 200 kHz bandwidth (BW).
  • BW bandwidth allocated for modulation of information carrying signals
  • the beacon is a sine wave with a frequency lower than the BW, modulated around for example the centre of the carrier frequency.
  • the beacon signal is a sine wave with a frequency between 0 and 200 kHz.
  • a beacon signal may be transmitted in more than one block 5, 5' whereby the beacon signal may be considered as a sequence of several beacons. Such a sequence of beacon signals may be combined by diversity combination of the IQ samples over time to increase the gain of the beacon. It is suggested that beacon signals can be transmitted in any or all of the blocks 5, 5' of Fig. 2.
  • Repeated transmission of subframes with only a single beacon signal may also be considered a sequence of beacon signals.
  • data communication between the transceiver device 1 and the UE 2 is carried in downlink and uplink channels and the downlink channel carries synchronization signals.
  • the beacon signal(s) may be comprised in the downlink channel.
  • the cell search procedure carried out by the UE 2 comprises receiving by the UE from the transceiver device a NPSS (narrow band primary synchronization signal) and a NSSS (narrowband secondary synchronization signal). It is noted, that since the UE search for a beacon and such searching is preferably carried out in a sleep mode with limited functionality, the UE may not consider the received signal as a NPSS or an NSSS signal, but the transceiver device 1 transmits the signals as NPSS and NSSS.
  • NPSS narrow band primary synchronization signal
  • NSSS narrow band secondary synchronization signal
  • beacon mappings to blocks 5 in the NB-IoT downlink are presented:
  • NPBCH refers to Narrow Band Physical Broadcast Channel.
  • the beacon signal modulated on the anchor carrier comprises in preferred embodiments two or more of said blocks of unused spectrum and a beacon signal is transmitted instead in at least two of said blocks of time blocks.
  • the transceiver device 1 is configured for transmitting beacons with regular intervals suitable for low-complexity diversity combining and detection. Such regular intervals could be achieved by placing beacons in whitespaces 5, 5' of Fig. 2, in any combination of NPSS and NPBCH (configurations A, C, E in table 1) or in NSSS only (configuration B in table 1).
  • the search for beacon signal(s) typically introduces two additional steps prior to the cell search procedure of NB-IoT:
  • Step 1 and 2 may be performed jointly or sequentially depending on the implementation.
  • the UE may perform PSS/SSS or NPSS/NSSS detection and/or synchronization as usual.
  • a beacon signal is in some embodiments assigned to have been detected if a correlation between a received signal(s) and an expected beacon signal(s) surpasses a given threshold. The magnitude of a threshold may be determined by experiments.
  • the UE is configured perform the cell search procedure, when a beacon signal is detected.
  • Fig. 4 schematically illustrates an IQ-diagram for beacon signals.
  • the I signal is a cosine waveform
  • the Q signal is a sine waveform.
  • a sine wave (without any additional phase) is shifted by 90° relative to a cosine wave.
  • Another way to express this, is that the sine and cosine waves are in quadrature.
  • the dotted line d illustrates the sample power whereas a denotes the angle between the x-axis and the sample power d.
  • the I/Q samples of the beacon signal traverses a circle (dotted circle) on the I/Q diagram.
  • Fig. 5 schematically illustrates a division of an anchor carrier into a set of detection channels based on the frequencies of each of the detection channels.
  • RB and RB' denotes the received beacon signals within the anchor carrier at a specific frequency, above 100 kHz and below 100+W kHz.
  • RB' refers to a beacon signal received subsequently to RB.
  • the UE may be configured to specifically search and detect beacon signals in this channel.
  • Fig. 6 shows a flow-chart of a method of modulating an anchor carrier signal of a transceiver device 1 to provide a beacon signal to a UE 2, the method comprising the following steps (SI to S4):
  • SI providing a transceiver device, o said transceiver device being configured to transmit information by modulating a signal on an anchor carrier 4 and the signal comprising a number of sub frames SF#0 to SF#9, wherein one or more of the sub frames comprises a spectral-temporal block 5, 5' that is unused, S2: transmitting a beacon signal in one or more of said block(s)
  • S3 providing a UE, said UE being configured for detecting a beacon signal
  • S4 performing a cell search if a beacon signal is detected.
  • Detection of a beacon signal can be carried out in different manners, and the following description focus on two ways:
  • the channel should cover a spectrum ⁇ W around the expected beacon frequency.
  • W is a spectral window to accommodate Doppler shift in NTN (non-terrestrial network) and clock uncertainties of UE (NB-IoT devices).
  • Energy detection relies on thresholding the sample power d whereas phase detection relies on the development of a. In both cases the SNR must be sufficient for accurate detection. In some cases energy detection may be more applicable to lower SNR cases while phase detection can be achieved by a very low complexity detector.
  • the UE is configured to detect a beacon signal by determining a phase development over time of a received signal. A beacon is detected if the phase of the received signal exhibits periodicity beyond a predefined threshold.
  • UE is configured to detect a beacon signal by determining the energy over time of the received signal. A beacon is detected if the energy of the received signal periodically is beyond a predefined threshold.
  • the UE is configured to make a rough estimate of the frequency and timing offsets based on the beacon sequence and adjust time and frequency offset.
  • the UE is configured for estimating the frequency offset and timing offset of the received beacon signals by comparing the frequency and inter-arrival times of detected beacons to the expected frequency of beacons, which is a function of the absolute radio-frequency channel number (ARFCN), and the expected time between beacons.
  • ARFCN absolute radio-frequency channel number
  • the UE is preferably configured to utilize estimations of the frequency offset and/or timing offset based on the beacon signal, in the cell search procedure when synchronising to NPSS and NSSS.
  • the UE 2 is synchronized to the carrier and in such embodiments, the UE is preferably configured to utilize the beacon signals to maintain carrier synchronization over time by estimating the frequency offset and/or the timing offset of expected beacon signals.
  • the estimation of frequency offset and/or timing offset of expected beacon signals may be performed as disclosed above.
  • a windowing function combined with a threshold may be used to identify the presence of beacons, i.e. a threshold function on the moving average of the sampled energy level on a channel.
  • Beacons can be combined in time to achieve a gain in SNR.
  • Combination of beacons may be performed by diversity combining of beacon signal repetitions with the intervals given by the well-known beacon sequence.
  • a gain may be achieved by dividing the potential beacon bandwidth into narrowband channels and performing the beacon detection on each channel, see fig. 5.
  • Two methods for separating the detected energy in channels are (a) utilizing a filter bank and (b) Fourier analysis like FFT or Spectral density estimation.
  • a filter bank should be designed with overlapping filters that cover the entire spectrum of fbeacon ⁇ W [Hz].
  • the sample rate of each channel should be large enough to get enough samples during the beacon period.
  • a per-channel sample rate of 180kHz gives ⁇ 38 samples per beacon.
  • the UE is configured to detecting a beacon signal by a phase-locked loop (PLL) comprising a voltage-control oscillator, wherein the beacon is detected if an internal control signal of the voltage-controlled oscillator is periodically steady in a manner coherent with a beacon sequence.
  • PLL phase-locked loop
  • a PLL circuit may be implemented in analogue hardware, which would make it low-cost and efficient for RF front-end circuits of the UE.
  • a PLL preferably comprises a phase comparator, a filter and a voltage-controlled oscillator (VCO).
  • the output of the VCO is a periodic function, which phase is locked to the phase of the input to the PLL. This is obtained by comparing the input to the PLL to the output of the VCO and generating a control signal for the VCO based on this.
  • PLL beacon detection utilizes the PLL-internal VCO control signal to identify beacons. A beacon is detected when this control signal is steady for a beacon period. Additionally, the frequency at which the beacon is received is a function of the control signal.
  • a sequence of beacons which surpasses the threshold for detection may need in some embodiments to pass a threshold for correlation to the expected interbeacon time and the beacon period.
  • the UE 2 may adjust the time and frequency of its RF front-end to aid in synchronization of the primary synchronization signal (such as PSS or NPSS) and secondary synchronization signal (such as SSS or NSSS).
  • the primary synchronization signal such as PSS or NPSS
  • secondary synchronization signal such as SSS or NSSS
  • the invention relates to a communication system, such as a nonterrestrial communication system, wherein a transceiver device 1, such as a satellite and/or base station, moves along a path at an altitude elevated from earth 3 and a user equipment device (UE) 2 located a position closer to the earth than the transceiver device 1, is in data communication with the base station.
  • the base station may be comprised in the transceiver device 1 with the base station and the transceiver device 1 configured to operate in a regenerative mode, or the base station may be located at a position away from the transceiver device 1 with the base station and the transceiver device 1 configured to operate in a transparent mode or regenerative mode.
  • the communication system is configured for transmitting information by modulating a signal on an anchor carrier 4, the signal comprising a number of sub frames SF#0 to SF#9, wherein one or more of the sub frames comprises a spectral-temporal block 5, 5' that is unused and wherein the transceiver device transmits a beacon signal in one or more of said block(s) to the UE which is configured for searching and/or detecting the beacon signal, and to perform a cell search if a beacon signal is detected.
  • the invention is particularly advantageous for prolonging the battery life of the UE 2, by configuring the UE 2 to enter a sleep mode, in which power consumption is reduced and the UE 2 only "listens" for the beacon, and enters an active mode for data communication with the transceiver device 1, when the beacon signal is detected.
  • a communication system comprising
  • a transceiver device (1) moving along a path at an altitude elevated from earth (3) and a UE (2) located a position closer to the earth than the transceiver device, such as located at or on the earth, the transceiver device is in data communication with the base station wherein the base station is either o comprised in the transceiver device with the base station and the transceiver device configured to operate in a regenerative mode, or o is located at a position away from the transceiver device with the base station and the transceiver configured to operate in a transparent mode; wherein
  • the transceiver device (1) is configured for o transmitting information by modulating a signal on an anchor carrier (4) and the signal comprising a number of sub frames (SF#0 to SF#9), wherein one or more of the sub frames comprises a spectral-temporal block (5, 5') that is unused, o transmitting a beacon signal in one or more of said block(s)
  • the UE is configured for o detecting a beacon signal, and o performing a cell search if a beacon signal is detected.
  • Item 2 A communication system according to item 1, wherein the anchor carrier has some bandwidth (BW) allocated for modulation of information carrying signals, such as a 200 kHz bandwidth (BW), and the beacon is a sine wave with a frequency lower than the carrier channels bandwidth (BW) modulated around for example the centre frequency of said carrier.
  • BW bandwidth allocated for modulation of information carrying signals
  • BW carrier channels bandwidth
  • Item 3 A communication system according to item 1 or 2, wherein the beacon signal is a sine wave with a frequency between 0 and 200 kHz.
  • Item 4. A communication system according to any one of the preceding items, wherein data communication between the transceiver device and the UE is carried in downlink and uplink channels and the downlink channel carries synchronization signals.
  • the cell search procedure comprises receiving by the UE from the transceiver device a NPSS (narrow band primary synchronization signal) and a NSSS (narrowband secondary synchronization signal).
  • NPSS narrow band primary synchronization signal
  • NSSS narrowband secondary synchronization signal
  • beacon signal modulated on the anchor carrier comprises two or more of said blocks of unused spectrum and a beacon signal is transmitted instead in at least two of said blocks of time blocks.
  • Item 7 A communication system according to any one of the preceding items, wherein a beacon signal is assigned to have been detected if a correlation between a received signal(s) and an expected beacon signal(s) surpasses a given threshold.
  • Item 8 A communication system according to any one of the preceding items, wherein the UE is configured perform the cell search procedure, when a beacon signal is detected.
  • Item 9 A communication system according to any one of the preceding items, wherein the beacon signal(s) is(are) modulated in one or more unused spectral- temporal blocks in a NPSS subframe.
  • Item 10 A communication system according to any one of the preceding items, wherein the beacon signal(s) is(are) modulated in one or more unused spectral- temporal blocks in a NSSS subframe.
  • Item 11 A communication system according to any one of the preceding items, wherein the beacon signal(s) is(are) modulated in one or more unused spectral- temporal blocks in a NPBCH subframe.
  • Item 12 A communication system according to any one of the preceding items, wherein the UE is configured to detect a beacon signal by determining a phase development over time of a received signal, wherein a beacon is detected if the phase of the received signal exhibits periodicity beyond a predefined threshold.
  • Item 13 A communication system according to any one of the preceding items, wherein the UE is configured to detect a beacon signal by determining the energy over time of the received signal, wherein a beacon is detected if the energy of the received signal periodically is beyond a predefined threshold.
  • Item 14 A communication system according to any one of the preceding items, wherein the beacon-signal is transmitted in a narrow bandwidth and the UE filters the base-band signal in a set of predefined spectrum slices, or channels, that potentially overlap and cover an expected spectral window for received signals that accommodates for Doppler shift, to obtain a set of received signals.
  • Item 15 A communication system according to any one of the preceding items, wherein the UE is configured for diversity combining, such as maximal ratio combining, of temporal repetitions of the received signal to improve the signal-to- noise ratio of the beacon signal.
  • diversity combining such as maximal ratio combining
  • Item 16 A communication system according to any one of the preceding items, wherein the UE is configured for estimating the frequency offset and timing offset of the received beacon signals by comparing the frequency and inter-arrival times of detected beacons to the expected frequency of beacons, which is a function of the absolute radio-frequency channel number (ARFCN), and the expected time between beacons.
  • ARFCN absolute radio-frequency channel number
  • Item 17 A communication system according to any one of the preceding items, wherein the UE is configured to utilize estimations of the frequency offset and/or timing offset based on the beacon signal, in the cell search procedure or synchronization procedure.
  • Item 18 A communication system according to any one of the preceding items, wherein the UE is configured to utilize the beacon signals to maintain carrier synchronization over time by estimating the frequency offset and/or the timing offset of expected beacon signals.
  • Item 19 A communication system according to any one of the preceding items, wherein the UE is configured, by hardware and/or software, to filter a signal on the spectrum where a beacon is expected to be located and configured for diversity combining said signal prior to passing the signal to a detector of the UE, and upon detection of a beacon, the UE is configured to use a detected beacon offset(s) for an initial frequency and offset estimation for the anchor carrier.
  • Item 20 A communication system according to item 19, wherein said filter is a hardware implemented analogous filter-bank, a software implemented digital filter-bank and/or a power spectral density estimations over the received spectrum.
  • Item 21 A communication system according to any one of the preceding items, wherein the UE is configured to detecting a beacon signal by a phase-locked loop comprising a voltage-control oscillator, wherein the beacon is detected if an internal control signal of the voltage-controlled oscillator is periodically steady in a manner coherent with a beacon sequence.
  • Item 22 A communication system according to any one of the preceding items, wherein the transceiver device is configured for transmitting beacons with regular intervals suitable for low-complexity diversity combining and detection.
  • Item 23 A method of modulating an anchor carrier signal of a transceiver device (1) to provide a beacon signal to a UE (2), the method comprising:
  • transceiver device • providing a transceiver device according to any of items 1 to 22, o said transceiver device being configured to transmit information by modulating a signal on an anchor carrier and the signal comprising a number of sub frames (SF#0 to SF#9), wherein one or more of the sub frames comprises a spectral-temporal block (5, 5') that is unused, o transmitting a beacon signal in one or more of said block(s) • providing a UE according to any of the items 1 to 22, said UE being configured for detecting a beacon signal, and
  • Item 24 A computer implemented method for modulating an anchor carrier signal of a transceiver device (1) to provide a beacon signal to a UE (2), the method comprising:

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Security & Cryptography (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un système de communication, tel qu'un système de communication non terrestre. Un dispositif émetteur-récepteur (1), tel qu'un satellite et/ou une station de base, se déplace le long d'un trajet à une altitude élevée par rapport à la terre (3), et un dispositif d'équipement utilisateur (UE) (2), situé à une position plus proche de la terre que le dispositif émetteur-récepteur (1), est en communication de données avec la station de base. La station de base peut être comprise dans le dispositif émetteur-récepteur (1) avec la station de base et le dispositif émetteur-récepteur (1) configuré pour fonctionner dans un mode régénératif, ou la station de base peut être située à une position éloignée du dispositif émetteur-récepteur (1) avec la station de base et le dispositif émetteur-récepteur (1) configuré pour fonctionner dans un mode transparent. Le système de communication est configuré pour transmettre des informations par modulation d'un signal sur une porteuse d'ancrage (4), le signal comprenant un certain nombre de sous-trames (SF#0 à SF#9). Une ou plusieurs des sous-trames comprennent un bloc spectral-temporel (5, 5') qui est inutilisé. De plus, le dispositif émetteur-récepteur émet un signal de balise dans un ou plusieurs desdits blocs vers l'UE qui est configuré pour rechercher et/ou détecter le signal de balise, et pour effectuer une recherche de cellule si un signal de balise est détecté. L'invention est particulièrement avantageuse pour prolonger la durée de vie de la batterie de l'UE (2), en configurant l'UE (2) pour entrer dans un mode de veille, dans lequel la consommation d'énergie est réduite et l'UE (2) "écoute" uniquement pour la balise, et entre dans un mode actif pour une communication de données avec le dispositif émetteur-récepteur (1), lorsque le signal de balise est détecté.
PCT/DK2023/050006 2022-01-12 2023-01-12 Balise nb-iot non terrestre Ceased WO2023134836A1 (fr)

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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200186321A1 (en) * 2018-04-02 2020-06-11 Lg Electronics Inc. Method for transmitting or receiving signal in wireless communication system, and device therefor

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20200186321A1 (en) * 2018-04-02 2020-06-11 Lg Electronics Inc. Method for transmitting or receiving signal in wireless communication system, and device therefor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
REN\'E BRANDBORG S{\O}RENSEN ET AL: "5G NB-IoT via low density LEO Constellations", ARXIV.ORG, CORNELL UNIVERSITY LIBRARY, 201 OLIN LIBRARY CORNELL UNIVERSITY ITHACA, NY 14853, 13 August 2021 (2021-08-13), XP091035163 *

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