WO2017171917A1 - Système et procédé de synchronisation d'événements dans des réseaux sans fil - Google Patents

Système et procédé de synchronisation d'événements dans des réseaux sans fil Download PDF

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Publication number
WO2017171917A1
WO2017171917A1 PCT/US2016/051556 US2016051556W WO2017171917A1 WO 2017171917 A1 WO2017171917 A1 WO 2017171917A1 US 2016051556 W US2016051556 W US 2016051556W WO 2017171917 A1 WO2017171917 A1 WO 2017171917A1
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WO
WIPO (PCT)
Prior art keywords
base stations
time
timing
network
activity
Prior art date
Application number
PCT/US2016/051556
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English (en)
Inventor
Eamonn Gormley
Original Assignee
Nokia Solutions And Networks Oy
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from US15/085,933 external-priority patent/US20160295426A1/en
Application filed by Nokia Solutions And Networks Oy filed Critical Nokia Solutions And Networks Oy
Priority to EP16897442.6A priority Critical patent/EP3437211A4/fr
Priority to US16/090,147 priority patent/US20190124524A1/en
Publication of WO2017171917A1 publication Critical patent/WO2017171917A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/02—Arrangements for optimising operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/04—Arrangements for maintaining operational condition

Definitions

  • Cellular radio networks generally have strict requirements for the accuracy of the transmit frequencies on which the networks operate.
  • the radio interfaces of GSM and UMTS base stations have a frequency accuracy requirement of ⁇ 50ppb (parts per billion).
  • Time Division Duplexing (TDD) networks require synchronization of airlink timing so that the downlink transmissions don't overlap with the uplink transmissions in time.
  • TDD Time Division Duplexing
  • the timing alignment of neighboring base stations should be within 2.5 ⁇ 8.
  • Frequency Division Duplexing (FDD) networks usually have no such requirement for their timing accuracy.
  • GSM and UMTS FDD networks do not have specified synchronization requirements.
  • the frame timing at one base station has no relation to the frame timing at other base stations.
  • CDMA2000 is a FDD technology.
  • CDMA2000 base stations are required to be aligned to CDMA system time (synchronous to Coordinated Universal Time (UTC) and use the same time origin as GPS time).
  • UTC Coordinated Universal Time
  • the timing error for CDMA2000 base stations should be less than 3us and shall be less than lOus.
  • Wireless communication systems that do not synchronize timing to an external timing reference are not capable of performing activities that rely on coordinating activities between multiple base stations.
  • Embodiments of the present disclosure are directed to wireless communications, and to a time-synchronized FDD communication system and method of synchronizing an FDD system.
  • Embodiments of the present disclosure relate to a method and system for establishing a common time base across a network of cellular base stations.
  • a method for synchronizing times across a plurality of base stations in a frequency division duplexing (FDD) wireless communications network includes receiving, at a plurality of base stations in the network, at least one timing reference signal associated with an external time reference, comparing the timing reference signal to an internal clock time of the plurality of base stations, receiving an instruction to perform an activity at a time relative to Coordinated Universal Time (UTC), and performing the activity, by the plurality of base stations, at the time relative to UTC.
  • FDD frequency division duplexing
  • the plurality of base stations wirelessly communicate with mobile devices using at least one of Long Term Evolution (LTE), Global System for Mobile (GSM) and Universal Mobile Telecommunications System (UMTS) communication technologies.
  • the timing reference signal may be a Network Timing Protocol (NTP) signal.
  • NTP Network Timing Protocol
  • the internal clock times of the base stations may be independent times that are specific to respective base stations without regard to any external reference time.
  • the activity instructs the base stations to hold coordinated parameters for at least 10 milliseconds.
  • Each base station of the plurality of base stations may receive a plurality of timing reference signals from a plurality of time servers.
  • the external time reference may be a satellite-based time reference or an atomic clock based time reference.
  • the plurality of base stations may be femtocell base stations in a cellular network.
  • FIG. 1 illustrates a wireless communications system according to an embodiment.
  • FIG. 2 illustrates a network resource controller according to an embodiment.
  • FIG. 3 illustrates a wireless network in which base stations are time synchronized to the GPS satellite constellation.
  • FIG. 4 illustrates a wireless network in which base stations are not time synchronized.
  • FIG. 5 illustrates a wireless network in which base stations are time synchronized to a common reference source.
  • FIG. 6 illustrates a process for time synchronization in a wireless communications network.
  • FIG. 7 illustrates a wireless communications system with time synchronized base stations according to an embodiment.
  • FIG. 8 illustrates a wireless communications system according to an embodiment.
  • FIG. 1 illustrates a networked communications system 100 according to an embodiment of this disclosure.
  • System 100 may include one or more base stations 102, each of which are equipped with one or more antennas 104. Each of the antennas 104 may provide wireless communication for user equipment (UE) 108 in one or more cells 106.
  • Base stations 102 have antennas 104 that are receive antennas which may be referred to as receivers, and transmit antennas, which may be referred to as transmitters.
  • the term "base station” refers to a wireless communications station provided in a location and serves as a hub of a wireless network.
  • a base station may be an eNodeB.
  • the base stations may provide service for macrocells, microcells, picocells, or femtocells. In other embodiments, the base station may be an access point in a Wi-Fi network.
  • the one or more UE 108 may include cell phone devices, mobile hotspots, laptop computers, handheld gaming units, electronic book devices and tablet PCs, and any other type of common portable wireless computing device that may be provided with wireless communications service by a base station 102.
  • any of the UE 108 may be associated with any combination of common mobile computing devices (e.g., laptop computers, tablet computers, cellular phones, mobile hotspots, handheld gaming units, electronic book devices, personal music players, video recorders, etc.), having wireless communications capabilities employing any common wireless data communications technology, including, but not limited to: GSM, UMTS, 3 GPP LTE, LTE Advanced, WiMAX, etc.
  • the system 100 may include a backhaul portion 116 that can facilitate distributed network communications between backhaul equipment or network controller devices 110, 112 and 114 and the one or more base station 102.
  • the backhaul portion of the network may include intermediate links 118 between a backbone of the network which are generally wire line, and sub networks or base stations located at the periphery of the network.
  • cellular mobile devices e.g., UE 108 communicating with one or more base station 102 may constitute a local sub network.
  • the network connection between any of the base stations 102 and the rest of the world may initiate with a link to the backhaul portion of a provider's communications network (e.g., via a point of presence).
  • the backhaul portion 116 of the system 100 of Figure 1 may employ any of the following common communications technologies: optical fiber, coaxial cable, twisted pair cable, Ethernet cable, and power-line cable, along with any other wireless communication technology known in the art.
  • wireless communications coverage associated with various data communication technologies typically vary between different service provider networks based on the type of network and the system infrastructure deployed within a particular region of a network (e.g., differences between GSM, UMTS, LTE, LTE Advanced, and WiMAX based networks and the technologies deployed in each network type).
  • Any of the network controller devices 110, 112 and 114 may be a dedicated Network Resource Controller (NRC) that is provided separately from the base stations or provided at the base station. Any of the network controller devices 110, 112 and 114 may be a non-dedicated device that provides NRC functionality. In another embodiment, an NRC is a Self-Organizing Network (SON) server. In an embodiment, any of the network controller devices 110, 112 and 114 and/or one or more base stations 102 may function independently or collaboratively to implement processes associated with various embodiments of the present disclosure.
  • NRC Network Resource Controller
  • SON Self-Organizing Network
  • any of the network controller devices 110, 112 and 114 may be associated with a base station controller (BSC), a mobile switching center (MSC), a data scheduler, or any other common service provider control device known in the art, such as a radio resource manager (RRM).
  • BSC base station controller
  • MSC mobile switching center
  • RRM radio resource manager
  • any of the network controller devices 110, 112 and 114 may be associated with a RNC, a serving GPRS support node (SGSN), or any other common network controller device known in the art, such as an RRM.
  • SGSN serving GPRS support node
  • any of the network controller devices 110, 112 and 114 may be associated with an eNodeB base station, a mobility management entity (MME), or any other common network controller device known in the art, such as an RRM.
  • MME mobility management entity
  • any of the network controller devices 110, 112 and 114, the base stations 102, as well as any of the UE 108 may be configured to run any well-known operating system. Any of the network controller devices 110, 112 and 114 or any of the base stations 102 may employ any number of common server, desktop, laptop, and personal computing devices.
  • FIG. 2 illustrates a block diagram of an NRC 200 that may be representative of any of the network controller devices 110, 112 and 114. Accordingly, NRC 200 may be representative of a Network Management Server (NMS), an Element Management Server (EMS), a Mobility Management Entity (MME), a SON server, etc.
  • the NRC 200 has one or more processor devices including a CPU 204.
  • the CPU 204 is responsible for executing computer programs stored on volatile (RAM) and nonvolatile (ROM) memories 202 and a storage device 212 (e.g., HDD or SSD).
  • storage device 212 may store program instructions as logic hardware such as an ASIC or FPGA.
  • Storage device 212 may store, for example, time information 214, an NTP client 216, and instructions 218.
  • the NRC 200 may also include a user interface 206 that allows an administrator to interact with the NRC's software and hardware resources and to display the performance and operation of the system 100.
  • the NRC 200 may include a network interface 208 for communicating with other components in the networked computer system, and a system bus 210 that facilitates data communications between the hardware resources of the NRC 200.
  • the NRC 200 may be used to implement other types of computer devices, such as an antenna controller, an RF planning engine, a core network element, a database system, or the like. Based on the functionality provided by an NRC, the storage device of such a computer serves as a repository for software and database thereto.
  • FIG. 3 illustrates a wireless system that has tightly coordinated airlink timing.
  • three base stations 302a, 302b and 302c are base stations in the same wireless network.
  • Each of the base stations 302a, 302b and 302c has a respective GPS receiver 312a, 312b and 312c that is wirelessly coupled to a GPS satellite 314 constellation. Therefore, airlink timing 308a, 308b and 308c associated with the respective base stations 302 can be tightly synchronized with one another.
  • the tight synchronization between the timing 308 is represented by the alignment of a leading edge in the timing pulses to a dashed line that represents a single point in time.
  • the GPS receiver 312 is one example of base station hardware for synchronizing airlink timing to a common time reference. When a GPS receiver 312 is used, it passes timing information to the base station 302 over a standard timing interface (e.g., GPS Pulse Per Second, (PPS)).
  • PPS GPS Pulse Per Second
  • Another example of such base station hardware is a timing module that extracts timing passed over backhaul connections (e.g., Tl, El, Ethernet).
  • Hardware that is dedicated to airlink time synchronization can provide a very accurate timing signal to each base station 302, allowing time synchronization to within a few microseconds.
  • the primary drawback with using specific hardware modules to establish a timing reference is the cost. Additionally, base stations that have already been deployed in the field may not have a provision for accepting an external timing signal. In such networks, hardware modules cannot be used to establish a common timing reference across the base stations in the network.
  • Time Division Duplexing (TDD) systems rely on tight time coordination to maintain a clean division between uplink and downlink times, so tightly synchronized signals 308 may exist in a UMTS TDD or CDMA2000 network of base stations.
  • FIG. 4 shows a wireless communications system including base stations 402a, 402b and 402c that are not tightly synchronized to a time reference. None of the base stations 402 are equipped with a GPS receiver. Accordingly, signals 410a, 410b and 410c are not aligned with one another, which is represented by the lack of alignment to the dashed line in FIG.4 that represents a single point in time.
  • Such a system may be representative of, for example, a GSM or UMTS or LTE FDD network of base stations.
  • FIG. 5 shows three base stations 506a, 506b and 506c, each respectively coupled to timing modules 504a, 504b and 504c.
  • the timing modules 504 are each independently coupled to a remote time reference source 502.
  • the base stations 506 can establish a local timing reference that may be tightly synchronized in time with respect to time reference source 502, which effectively synchronizes the base stations to one another.
  • the timing modules 504 may include instructions for performing processes of this disclosure that are recorded on a computer readable medium of the base stations.
  • the hardware component of the timing modules 504 is pre-existing computer hardware of the base stations 506.
  • the base stations 506 may be base stations in a wireless FDD network that are not equipped with GPS receivers.
  • the base stations 506 may transmit and/or receive unsynchronized signals 510a, 510b and 510c, respectively. However, when the time synchronization modules 504 are coupled between a time reference source 502 and a base station 506, the base stations can synchronize to that time reference source.
  • a scheduled event For networks that have timing alignment requirements, it is relatively straightforward to schedule future events to occur on or about the same time throughout the network.
  • An example of such a scheduled event is for automated interference detection during coordinated listening times. In such a system, all base stations are instructed to establish a simultaneous quiet time, where the mobile devices and/or base stations in the network are instructed not to transmit.
  • Another example of a scheduled event is a synchronized network parameter update, where the network parameter is scheduled to take effect at each base station at the same time. Examples of such parameters are transmit power, or a handover offset parameter.
  • NTP Network Timing Protocol
  • IP Internet Protocol
  • NTP Network Timing Protocol
  • SNTP Simple Network Timing Protocol
  • PTP Precision Timing Protocol
  • IEEE 1588 IEEE 1588
  • PTP can achieve sub-microsecond timing alignment.
  • it makes use of hardware timestamps applied at the physical layer at each end of a connection - hence, the base station Ethernet interfaces would already have to support such time stamping, which is generally not the case.
  • PTP is generally intended for deployment over a local area network and may not be applicable over the backhaul networks connecting multiple base stations.
  • FIG. 6 illustrates an embodiment of a process 600 for time synchronization in a wireless communications network.
  • one or more time reference signal is received by a base station at S602.
  • Process 600 may be performed by one or more base station.
  • FIG. 7 illustrates a wireless communications system 700 with time synchronized base stations according to an embodiment.
  • the communications system includes a time reference source 702 coupled to a plurality of time servers 704, which are in turn coupled to a plurality of base stations 706.
  • the time reference may be relative to Coordinated Universal Time (UTC), which is the primary global time standard.
  • UTC Coordinated Universal Time
  • the time reference source 702 may be a GPS satellite or an atomic clock.
  • the time reference source 702 transmits timing information to one or more time server 704.
  • the time servers 704 may be standalone servers that are dedicated to the purpose of distributing time information from the time source 702 to other networked entities.
  • a time server may be integrated with a Network Resource Controller such as NRC 200, which is coupled to a backhaul of a wireless network.
  • NRC 200 a Network Resource Controller
  • hardware such as a GPS receiver or NIST modem may be installed at the NRC, which in turn can distribute timing information to network nodes.
  • the time servers 704 are public or government servers. Such servers may be coupled to the Intemet for the purpose of distributing time information from the time source 702.
  • FIG. 7 shows the base stations receiving timing information directly from a plurality of time servers 704, other embodiments are possible.
  • the base stations may be coupled to the time source 702 through a time server 704 as well as additional computer entities.
  • the base stations receive timing information from a plurality of computing devices, which may be time servers 704, or otherwise coupled to time servers 704.
  • the base stations could synchronize to one another through X2 or other interfaces to improve or confirm tight synchronization.
  • the time servers 704 are Stratum 1 computers of an NTP system, while the time source 702 is a Stratum 0 device.
  • the base stations may receive time reference signals at S602 that originated at the time source 702, and pass through one or more Stratum before arriving at the base station 706.
  • the timing accuracy at base stations 706 can be increased by increasing the number of signals that are received at S602. Accordingly, the base stations 706 may receive multiple signals from multiple time servers 704 at S602.
  • FIG. 8 illustrates an embodiment of a wireless communications system in which a time server 804 is located within a central controller device 802.
  • the central controller device 802 may be a central network controller such as an MME or a SON server.
  • the central controller 802 is in communication with a time agent 812 at a base station 806 through backhaul elements 810.
  • the time agent 812 contains an NTP client 814.
  • the time agent 812 uses NTP to establish a time base reference with a time server 804 which includes NTP software.
  • the centralized controller 802 and time server 804 are implemented on different machines.
  • the base station 806 establishes a reference time based on time information received from the time server 804 at S604.
  • the reference time may be established by a time agent 812 deployed at base station 806.
  • the time agent 812 may include software that is coupled between the base station protocol stack software 820 and central controller 802.
  • the software agent may be supplied by a third party to the base station software vendor.
  • the base station protocol stack software 820 may encompass all software apart from software associated with the time agent 812 that resides at the base station 806.
  • the time base established at S604 is not shared with other software or hardware at the base station 806 and is known only to the time agent 812. While NTP time synchronization may not facilitate synchronization to the same degree of alignment as a GPS receiver, it can be used in cases where it is acceptable that the events at each base station 806 are synchronized to within a few milliseconds of each other.
  • the time agent 812 also communicates with the existing base station protocol stack 820 over an Application Programming Interface (API) 830.
  • API Application Programming Interface
  • the existing base station protocol stack 820 provides periodic timestamps from internal clock 824 to the time agent 812 over the API 830. In this manner, the time agent 812 learns the time base used by the base station protocol stack software 820.
  • a reference time established by the time agent 812 based on time information from one or more time server 804 is compared to timing from the intemal clock 824 of the base station by a timing comparator 816 at S606.
  • time agent 812 compares relative timing between the time base established by the time agent 812 with the time server 804, and the time base of internal clock 824 communicated by the base station protocol stack 820 over the software agent API 830.
  • the output of the timing comparator is transmitted to a time base converter 818, and the reference time maintained by the time agent 812 is correlated with the base station clock timing at S608.
  • the timing comparator 816 may establish an offset between the reference time maintained by time agent 812 and the intemal clock 824.
  • the time base converter 818 converts timing information from one time base to another time base. Accordingly, times of the intemal clock 824 of base station 806 may be indexed to a reference time maintained by time agent 812, so that protocol stack timing messages 822 can be linked to UTC time through the time agent.
  • Instructions for performing a time-coordinated activity are received at S610.
  • the instructions may be received from a central controller entity, or NRC 200, coupled to the base station 806 through backhaul 810.
  • a centralized controller 802 informs the time agent 812 when to schedule an event.
  • FIG. 8 shows the central controller 802 as being the controller that houses the time server 804, in other embodiments, the instruction for the coordinated activity may be received from some other central network controller.
  • the centralized controller 802 schedules the event to occur at or about the same time at multiple base stations 806 by sending messages to the base stations informing them all of the time at which the event is to occur.
  • the time indicated in the message sent by the centralized controller 802 is relative to the time of the reference time source 702, which is the same as the time base established at the time agents 812 at each base station 806.
  • the time agent 812 at each base station 806 receives the message to perform a coordinated activity from the centralized controller 802, it converts the event time contained in the message from the synchronized time base to the time base used by the base station protocol stack 820 using the time base converter 818.
  • each of them will schedule the event to occur at the same absolute time. Accordingly, when the coordinated activity is performed at S612, the activity is performed at the same time by all such time-synchronized base stations, even when the base stations are FDD base stations that are not equipped with dedicated time synchronization hardware.
  • the synchronized activity may include an event, such as a series of blank (quiet) frames or holding a particular phase or power level, that lasts for longer than 10 milliseconds. In another embodiment, the event may be longer than 50 or 100 milliseconds.
  • the synchronized activity performed at S612 may be determined by a network operator. As communication networks evolve, increasingly sophisticated tools are available to network operators to optimize performance of wireless communications networks. A non- limiting list of some of the coordinated activities that are made possible by embodiments of the present disclosure includes beamforming between multiple base stations, phase coordination as described, for example, by U.S. Patent No. 8,412,246, load balancing, coordinating quiet times, interference detection, power level coordination, etc.
  • Embodiments of this disclosure provide numerous advantages to conventional wireless communications technologies. Embodiments may be implemented using preexisting hardware at base stations, without incurring the time and expense for installing dedicated location hardware. Some embodiments may be applied to indoor base stations, where it is difficult to receive a GPS signal, and where dedicated timing hardware costs can be prohibitive. NTP can be implemented over the Internet, which is generally available to indoor base stations.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé de synchronisation d'horloges sur une pluralité de stations de base dans un réseau de communication sans fil à duplexage par répartition en fréquence (FDD). Ce procédé consiste à recevoir, au niveau d'une pluralité de stations de base du réseau, au moins un signal de référence de synchronisation associé à une référence temporelle externe ; à comparer le signal de référence de synchronisation à des heures d'horloges internes de la pluralité de stations de base ; à recevoir une instruction visant à réaliser une activité à une certaine heure par rapport au temps universel coordonné (UTC) ; et à réaliser l'activité, par la pluralité de stations de base, à l'heure donnée par rapport au temp universel coordonné.
PCT/US2016/051556 2015-03-30 2016-09-13 Système et procédé de synchronisation d'événements dans des réseaux sans fil WO2017171917A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP16897442.6A EP3437211A4 (fr) 2015-03-30 2016-09-13 Système et procédé de synchronisation d'événements dans des réseaux sans fil
US16/090,147 US20190124524A1 (en) 2015-03-30 2016-09-13 System and method for event synchronization in wireless networks

Applications Claiming Priority (3)

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US201562140217P 2015-03-30 2015-03-30
US15/085,933 US20160295426A1 (en) 2015-03-30 2016-03-30 Method and system for communication networks
US15/085,933 2016-03-30

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Publication number Priority date Publication date Assignee Title
US11973548B2 (en) 2022-02-03 2024-04-30 T-Mobile Usa, Inc. Adjusting a configuration of a wireless telecommunication network

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080075061A1 (en) * 2006-08-29 2008-03-27 Ubiquisys Limited Synchronising base stations
US20080287153A1 (en) * 2007-05-15 2008-11-20 Scott Fullam Clock synchronization for a wireless communications system
US20120262339A1 (en) * 2011-04-15 2012-10-18 Itt Manufacturing Enterprises, Inc. Determination of State Vector, Timing, and Navigation Quality Metrics from Reception of ADS-B Transmissions
US20140133584A1 (en) * 2012-11-12 2014-05-15 Mediatek Inc. Bluetooth device and related communications establishing method
US20150163049A1 (en) * 2012-06-18 2015-06-11 Niclas Nors Time domains in a pon

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8274947B1 (en) * 2007-10-05 2012-09-25 Zte (Usa) Inc. Providing timing reference for femto cell in wireless communication networks
US20100054237A1 (en) * 2008-09-04 2010-03-04 Motorola, Inc. Synchronization for femto-cell base stations
US8614975B2 (en) * 2008-09-19 2013-12-24 Qualcomm Incorporated Synchronizing a base station in a wireless communication system
WO2014060225A1 (fr) * 2012-10-17 2014-04-24 Telefonica, S.A. Procédé pour conférer une synchronisation de phase à des stations de base cellulaires non synchronisées en phase
US9750044B2 (en) * 2013-05-10 2017-08-29 Qualcomm Incorporated Methods and apparatus for network synchronization

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080075061A1 (en) * 2006-08-29 2008-03-27 Ubiquisys Limited Synchronising base stations
US20080287153A1 (en) * 2007-05-15 2008-11-20 Scott Fullam Clock synchronization for a wireless communications system
US20120262339A1 (en) * 2011-04-15 2012-10-18 Itt Manufacturing Enterprises, Inc. Determination of State Vector, Timing, and Navigation Quality Metrics from Reception of ADS-B Transmissions
US20150163049A1 (en) * 2012-06-18 2015-06-11 Niclas Nors Time domains in a pon
US20140133584A1 (en) * 2012-11-12 2014-05-15 Mediatek Inc. Bluetooth device and related communications establishing method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3437211A4 *

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EP3437211A1 (fr) 2019-02-06

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