WO2014127797A1 - Déploiement de petites cellules dans le domaine des télécommunications - Google Patents

Déploiement de petites cellules dans le domaine des télécommunications Download PDF

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Publication number
WO2014127797A1
WO2014127797A1 PCT/EP2013/053228 EP2013053228W WO2014127797A1 WO 2014127797 A1 WO2014127797 A1 WO 2014127797A1 EP 2013053228 W EP2013053228 W EP 2013053228W WO 2014127797 A1 WO2014127797 A1 WO 2014127797A1
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WIPO (PCT)
Prior art keywords
user terminal
macro cell
inter
frequency
cell
Prior art date
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PCT/EP2013/053228
Other languages
English (en)
Inventor
Johanna Katariina Pekonen
Antti Anton Toskala
Woonhee Hwang
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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.)
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Publication date
Application filed by Nokia Solutions And Networks Oy filed Critical Nokia Solutions And Networks Oy
Priority to PCT/EP2013/053228 priority Critical patent/WO2014127797A1/fr
Publication of WO2014127797A1 publication Critical patent/WO2014127797A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/04—Reselecting a cell layer in multi-layered cells
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0033—Control or signalling for completing the hand-off for data sessions of end-to-end connection with transfer of context information
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/24—Reselection being triggered by specific parameters
    • H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
    • H04W36/305—Handover due to radio link failure

Definitions

  • the exemplary and non-limiting embodiments of this invention relate generally to wireless communications networks, and more particularly to small cell deployment.
  • a pico cell is a small network cell typically covering a small area, such as an office, shopping mall, train station, stock exchange, etc.
  • pico cells may be used to extend coverage in indoor areas where outdoor signals do not reach well, or to add network capacity in areas with very dense phone usage, such as train stations.
  • Pico cells enable coverage and capacity in areas difficult or expensive to reach.
  • a pico cell base station may be a low cost, small unit that connects to a radio network controller (RNC) or to another macro cell.
  • RNC radio network controller
  • Pico cells offer many of the benefits of small cells such as improving data throughput and increasing capacity in the mobile network.
  • the integration of pico cells with macro cells through a heterogeneous network may be useful in seamless handovers and increased mobile data capacity.
  • An aspect of the invention relates to a method comprising transmitting, from a first network apparatus of a macro cell, a configuration message to a user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of a small cell; receiving in the first network apparatus a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the small cell; initiating a handover of the user terminal from the first network apparatus to a second network apparatus of the small cell; indicating to the second network apparatus that the user terminal's context information remains in the first network apparatus, in order the second network apparatus to configure the user terminal to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receiving from the second network apparatus a message requesting the first network apparatus to remove the user terminal's context from the first network apparatus due to a macro cell radio link related
  • a further aspect of the invention relates to a method comprising performing a handover of the user terminal from a first network apparatus of a macro cell to a second network apparatus of a small cell; receiving in the second network apparatus an indication that the user terminal's context information remains in the first network apparatus; transmitting, from the second network apparatus, a configuration message to the user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receiving in the second network apparatus a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the macro cell; wherein, if the measurement report indicates a macro cell radio link related problem detected in the user terminal, the method comprises transmitting from the second network apparatus a message requesting the first network apparatus to remove the user terminal's context from the first network
  • a still further aspect of the invention relates to a method comprising receiving, in a user terminal from a first network apparatus of a macro cell, a configuration message in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of a small cell; based on the receiving, performing, in the user terminal, the inter- frequency measurement on the frequency band of the small cell; transmitting to the first network apparatus a measurement report regarding the inter-frequency measurement performed in the user terminal on the frequency band of the small cell; performing a handover of the user terminal from the first network apparatus to a second network apparatus of the small cell; receiving, from the second network apparatus, a configuration message in order to configure the user terminal to perform an inter-frequency
  • the method comprises transmitting to the second network apparatus a measurement report regarding the inter-frequency measurement performed in the user terminal on the frequency band of the macro cell, in order the user terminal's context to be removed from the first network apparatus.
  • a still further aspect of the invention relates to a first apparatus of a macro cell, the first apparatus comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to transmit a configuration message to a user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of a small cell; receive a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the small cell; initiate a handover of the user terminal from the first apparatus to a second apparatus of the small cell; indicate to the second apparatus that the user terminal's context information remains in the first apparatus in order the second network apparatus to configure the user terminal to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receive from the second apparatus
  • a still further aspect of the invention relates to a second apparatus of a small cell, the second apparatus comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to perform a handover of a user terminal from a first apparatus of a macro cell to the second apparatus; receive an indication that the user terminal's context information remains in the first apparatus; transmit a configuration message to the user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a
  • the measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receive a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the macro cell; wherein, if the measurement report indicates a macro cell radio link related problem detected in the user terminal, the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to based on the received measurement report, transmit a message requesting the first apparatus to remove the user terminal's context from the first apparatus.
  • a still further aspect of the invention relates to a terminal apparatus comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal apparatus to receive, from a first apparatus of a macro cell, a configuration message in order to configure the terminal apparatus to perform an inter-frequency measurement on a frequency band of s small cell; based on the receiving, perform the inter-frequency measurement on the frequency band of the small cell; transmit to the first apparatus a measurement report regarding the inter-frequency measurement performed in the terminal apparatus on the frequency band of the small cell; perform a handover of the terminal apparatus from the first apparatus to a second apparatus of the small cell; receive, from the second apparatus, a configuration message in order to configure the terminal apparatus to perform an inter-frequency measurement on a frequency band of the macro cell; based on the receiving, perform the inter-frequency measurement on the frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a measurement trigger which is triggered,
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal apparatus to transmit to the second apparatus a measurement report regarding the inter-frequency measurement performed in the terminal apparatus on the frequency band of the small cell, in order the terminal apparatus's context to be removed from the first apparatus.
  • a still further aspect of the invention relates to a computer program product comprising program code means configured to perform any of the method steps when the program is run on a computer.
  • a still further aspect of the invention relates to a computer-readable storage medium comprising program code means configured to perform any of the method steps when executed on a computer.
  • Figure 1 illustrates an exemplary scenario in which a macro eNB remains a RRC anchoring point while offloading UE to a pico eNB;
  • Figure 2 illustrates an exemplary scenario in which a macro eNB maintains a UE context after a handover, and removes it first after getting an indication from a serving pico eNB;
  • Figure 3 shows a simplified block diagram illustrating exemplary system architecture
  • Figure 4 shows a simplified block diagram illustrating exemplary apparatuses
  • Figure 5 shows a messaging diagram illustrating an exemplary messaging event according to an embodiment of the invention
  • Figure 6 shows a schematic diagram of a flow chart according to an exemplary embodiment of the invention
  • Figure 7 shows a schematic diagram of a flow chart according to another exemplary embodiment of the invention.
  • Figure 8 shows a schematic diagram of a flow chart according to another exemplary embodiment of the invention.
  • 3GPP Release-12 on small cell studies improves the operation of small cells (with and without co-operation with macro cells).
  • One of the scenarios considered in 3GPP Release- 12 is such that UE may be connected at the same time both to a macro cell and a small cell, but a user plane might be provided only via the small cell, while RRC connection maintenance may be on the responsibility of the macro cell.
  • the scenario may be such that one eNB controls multiple cells including macro cells and pico cells and UE is connected via pico cell.
  • the small cells have a limited (small) coverage area and therefore it has been considered beneficial to keep the RRC connection running via the macro cell (even though actual radio connection is provided via the small cell).
  • a (high bit rate) data stream is coming from the small cell as well as RRC signalling over the small cell radio, intra-frequency mobility decisions are based on measurements on the small cell frequency, otherwise the selection of the serving may not be correct.
  • the mobility measurements done from the small cell frequency may not trigger a measurement report transmission from another frequency if the small cell has good quality signal. Thus the macro cell may be disappearing and not being noticed.
  • the lack of measurement report from the macro cell responsible of the RRC connection may cause a problem if the small cell connection is lost and UE is still assuming the macro cell as a back-up solution (as has been suggested in the small cell discussions as there is increased probability for connection loss at high frequency small cells).
  • the carrier aggregation is not used, especially if the small cell frequency is considered large enough (such as 3,5 GHz case) so that the data rate achieved using only 3,5 GHz case is sufficient, as has also been suggested in the related small cell discussions.
  • the aggregation approach may not contribute too much from the data rate point of view even if the small cell bandwidth is similar as in the macro cell, thus it is better to serve only via a single cell rather than trying to aggregate.
  • UE may try RRC connection re-establishment every time toward the macro cell after a handover out of the pico cell is failed.
  • it cannot be guaranteed that the macro cell is there every time as macro coverage has been disappeared already.
  • the network may configure UE to measure inter- frequency of the macro cell and also enable measurement triggering if the measured inter- frequency becomes smaller than a threshold value or offset becomes worse than that of a serving cell serving the user terminal UE.
  • the network may initiate additional measurements, for example, measurements on the 3G side or on another LTE macro cell frequency band, which is not needed if one is able to trust the original macro cell (with an "RRC connection anchor point") coverage being there.
  • the network may then inform UE that the macro cell is no longer the "anchor point" and, for example, no longer a target for the re-establishment.
  • the network may also trigger a transfer of a UE context with the handover to the small cell and this measurement may be used to determine, if the context is to be deleted from the macro cell (since the macro cell is no longer accessible by UE).
  • UE is served by eNB1 (macro); 2) handover to eNB2 (pico); 3) as part of the handover signalling, eNB1 indicates to eNB2 that UE context information remains in the macro cell; 4) eNB configures the new measurement to find out when the macro coverage disappears; 5) based on that measurement report information received from UE, eNB2 indicates to eNB1 that the UE context should be removed.
  • the network is able to configure a new measurement issue when UE is entering such a small cell where problems have been detected in the past, thus avoiding spending effort on measurements when in such a small cell where macro coverage is ensured.
  • An exemplary embodiment is a part of UE related signalling in 3GPP.
  • the respective network behaviour may be visible from the network responding to the UE measurement report and informing the change of the macro cell status.
  • Figure 1 illustrates a scenario in which the macro eNB remains the RRC anchoring point while offloading UE to the pico eNB.
  • Figure 2 illustrates a scenario in which the macro eNB maintains the UE context after the handover and removes it first after getting an indication from the serving pico eNB.
  • An exemplary embodiment thus relates to a scenario in 3GPP release 12 heterogeneous networks where user plane is provided only via the small cell while radio resource control (RRC) connection maintenance is on the responsibility of the macro cell.
  • RRC radio resource control
  • the mobility measurements done from the small cell frequency may not trigger a measurement report from another frequency, if the small cell has good coverage.
  • the macro cell coverage may be disappearing and not being noticed by UE.
  • the network configures UE to measure inter-frequency of the macro cell and enable also measurement trigger if the inter-frequency signal becomes weaker than a threshold value.
  • the network Upon receiving the measurement report from UE, the network (via the small cell) informs UE that the macro cell is no longer the "anchor point" and, for example, no longer a target for re-establishment.
  • An exemplary embodiment prevents UE from losing the physical connection to macro cell while being connected to the small cell but e.g. still with control plane under control of the overlay macro cell.
  • An exemplary embodiment enables autonomous UE mobility in LTE small cell deployment. In heterogeneous network deployments the limited coverage of the small cell may cause a radio link failure due to the lost serving small cell coverage. Existing solutions use re- establishment to macro overlay for such an RLF case.
  • the small cells are located at the edge of the macro cell coverage and the mobility measurements done from the small cell frequency may not trigger a measurement report transmission from another frequency if the small cell has a good quality signal.
  • the macro overlay cell may be disappearing and not being noticed.
  • An exemplary embodiment thus enhances the measurement triggering for the inter-frequency case.
  • the present invention is applicable to any user terminal, server, corresponding
  • the communication system may be a fixed communication system or a wireless communication system or a communication system utilizing both fixed networks and wireless networks.
  • FIG. 3 A general architecture of a communication system is illustrated in Figure 3.
  • Figure 3 is a simplified system architecture only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown.
  • connection shown in Figure 3 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the systems also comprise other functions and structures. It should be appreciated that the functions, structures, elements and the protocols used in or for small cell deployment, are irrelevant to the actual invention. Therefore, they need not to be discussed in more detail here.
  • the exemplary radio system of Figure 3 comprises a network node 301 of a network operator.
  • the network node 301 may include e.g. an LTE base station eNB1 of a macro cell, radio network controller (RNC), or any other network element, or a combination of network elements.
  • the network node 301 may be connected to one or more core network (CN) elements (not shown in Figure 3) such as a mobile switching centre (MSC), MSC server (MSS), mobility management entity (MME), serving gateway (SGW), gateway GPRS support node (GGSN), serving GPRS support node (SGSN), home location register (HLR), home subscriber server (HSS), visitor location register (VLR).
  • MSC mobile switching centre
  • MME mobility management entity
  • SGW serving gateway
  • GPRS support node GGSN
  • serving GPRS support node SGSN
  • HLR home subscriber server
  • VLR visitor location register
  • the radio network node 301 that may also be called eNB1 (enhanced node-B, evolved node-B) or network apparatus of the radio system, hosts the functions for radio resource management in a public land mobile network.
  • the exemplary radio system of Figure 3 comprises a network node 302 of a network operator.
  • the network node 302 may include e.g.
  • the network node 302 may be connected to one or more core network (CN) elements (not shown in Figure 3) such as a mobile switching centre (MSC), MSC server (MSS), mobility management entity (MME), serving gateway (SGW), gateway GPRS support node (GGSN), serving GPRS support node (SGSN), home location register (HLR), home subscriber server (HSS), visitor location register (VLR).
  • CN core network
  • the radio network node 302 that may also be called eNB2 (enhanced node-B, evolved node-B) or network apparatus of the radio system, hosts the functions for radio resource management in a small cell (e.g. pico cell) of a public land mobile network.
  • FIG 3 shows a user equipment 303 located in the service area of the radio network node 301 , 302.
  • the user equipment refers to a portable computing device, and it may also be referred to as a user terminal.
  • Such computing devices include wireless mobile communication devices operating with or without a subscriber identification module (SIM) in hardware or in software, including, but not limited to, the following types of devices: mobile phone, smart-phone, personal digital assistant (PDA), handset, laptop computer.
  • SIM subscriber identification module
  • the user equipment 303 is capable of connecting to the radio network node 301 , 302 via a (cellular radio) connection 304, 305, respectively.
  • the radio network node 301 may be capable of connecting to the radio network node 302 via a connection 306.
  • Figure 4 is a block diagram of an apparatus according to an embodiment of the invention.
  • Figure 4 shows a user equipment 303 located in the area of a radio network node 301 , 302.
  • the user equipment 303 is configured to be in connection with the radio network node 301 , 302.
  • the user equipment or UE 303 comprises a controller 401 operationally connected to a memory 402 and a transceiver 403.
  • the controller 401 controls the operation of the user equipment 303.
  • the memory 402 is configured to store software and data.
  • the transceiver 403 is configured to set up and maintain a wireless connection 304, 305 to the radio network node 301 , 302, respectively.
  • the transceiver 403 is operationally connected to a set of antenna ports 404 connected to an antenna arrangement 405.
  • the antenna arrangement 405 may comprise a set of antennas.
  • the number of antennas may be one to four, for example.
  • the number of antennas is not limited to any particular number.
  • the user equipment 303 may also comprise various other components, such as a user interface, camera, and media player. They are not displayed in the figure due to simplicity.
  • the radio network node 301 , 302 such as an LTE (or LTE-A) base sta-tion (eNode-B, eNB) comprises a controller 406 operationally connected to a memory 407, and a transceiver 408.
  • the controller 406 controls the operation of the radio network node 301 .
  • the memory 407 is configured to store software and data.
  • the transceiver 408 is configured to set up and maintain a wireless connection to the user equipment 303 within the service area of the radio network node 301 , 302.
  • the transceiver 408 is operationally connected to an antenna arrangement 409.
  • the antenna arrangement 409 may comprise a set of antennas.
  • the number of antennas may be two to four, for example. The number of antennas is not limited to any particular number.
  • the radio network node 301 , 302 may be operationally connected (directly or indirectly) to another network element of the communication system, such as a further radio network node 301 , 302 (via a connection 306), radio network controller (RNC), a mobility management entity (MME), a serving gateway (SGW), an MSC server (MSS), a mobile switching centre (MSC), a radio resource management (RRM) node, a gateway GPRS support node, an operations, administrations and maintenance (OAM) node, a home location register (HLR), a visitor location register (VLR), a serving GPRS support node, a gateway, and/or a server, via an interface 410.
  • RNC radio network controller
  • MME mobility management entity
  • SGW serving gateway
  • MSS MSC server
  • MSC mobile switching centre
  • RRM radio resource management
  • gateway GPRS support node an operations, administrations and maintenance (OAM) node
  • HLR home location register
  • VLR visitor location register
  • IP internet protocol
  • the apparatus 301 , 302, 303 has been depicted as one entity, different modules and memory may be implemented in one or more physical or logical entities.
  • the apparatus may also be a user terminal which is a piece of equipment or a device that associates, or is arranged to associate, the user terminal and its user with a subscription and allows a user to interact with a communications system.
  • the user terminal presents information to the user and allows the user to input information.
  • the user terminal may be any terminal capable of receiving information from and/or transmitting information to the network, connectable to the network wirelessly or via a fixed connection. Examples of the user terminals include a personal computer, a game console, a laptop (a notebook), a personal digital assistant, a mobile station (mobile phone), a smart phone, and a line telephone.
  • the apparatus 301 , 302, 303 may generally include a processor, controller, control unit or the like connected to a memory and to various inter-faces of the apparatus.
  • the processor is a central processing unit, but the processor may be an additional operation processor.
  • the processor may comprise a computer processor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and/or other hardware compo-nents that have been programmed in such a way to carry out one or more functions of an embodiment.
  • the memory 402, 407 may include volatile and/or non-volatile memory and typically stores content, data, or the like.
  • the memory 402, 407 may store computer program code such as software applications (for example for the detector unit and/or for the adjuster unit) or operating systems, information, data, content, or the like for a processor to perform steps associated with operation of the apparatus in accordance with
  • the memory may be, for example, random access memory (RAM), a hard drive, or other fixed data memory or storage device. Further, the memory, or part of it, may be removable memory detachably connected to the apparatus.
  • RAM random access memory
  • the memory, or part of it, may be removable memory detachably connected to the apparatus.
  • an apparatus implementing one or more functions of a corresponding mobile entity described with an embodiment comprises not only prior art means, but also means for implementing the one or more functions of a corresponding apparatus described with an embodiment and it may comprise separate means for each separate function, or means may be configured to perform two or more functions.
  • these techniques may be implemented in hardware (one or more apparatuses), firmware (one or more
  • firmware or software implementation can be through modules (e.g. procedures, functions, and so on) that perform the functions described herein.
  • the software codes may be stored in any suitable, processor/computer-readable data storage medium(s) or memory unit(s) or article(s) of manufacture and executed by one or more processors/computers.
  • the data storage medium or the memory unit may be implemented within the processor/computer or external to the processor/computer, in which case it can be communicatively coupled to the processor/computer via various means as is known in the art.
  • a network node 301 (which may comprise e.g. a LTE-capable base station (enhanced node-B, eNB1 ) of a macro cell) may configure a user terminal 303 (which may also be referred to as a user equipment UE), by transmitting a configuration message 501 to the user terminal 303, to measure inter-frequency of the small cell (e.g. pico cell).
  • the user terminal 303 may receive the configuration message 501 and perform a measurement on a small cell (e.g. pico cell) frequency band.
  • the user terminal 303 may transmit a measurement report to eNB1 301.
  • eNB1 301 may receive the measurement report from UE 303. If the report indicates e.g. that small cell (e.g. pico cell) radio connection is good, the network may initiate a handover of UE 303 from eNB1 301 to a network node 302 (which may comprise e.g. a LTE-capable base station
  • eNB1 enhanced node-B, eNB2 of the small cell (e.g. pico cell)
  • eNB1 sends a handover preparation message 505 to eNB2 indicating that eNB1 is keeping the UE context.
  • eNB2 returns a handover acknowledgement 506 to eNB1 with a handover command, and eNB1 forwards 507 the handover command to UE.
  • a handover of UE 303 (served by eNB1 301 (macro cell)) to eNB2 302 (pico cell) is initiated.
  • eNB1 301 may indicate to eNB2 302 that UE context information remains in eNB1 301 , wherein eNB2 may forward the indication to UE (not shown in Figure 5).
  • eNB2 302 may configure UE 303, by transmitting a configuration message 51 1 to UE 303, to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered if the inter-frequency neighbour becomes lower than a threshold value or if an inter-frequency neighbour offset becomes worse than that of the serving cell serving the user terminal 303.
  • UE 303 may receive the configuration message 51 1 and perform a measurement on the macro cell frequency band.
  • UE 303 may transmit a measurement report to eNB2 302.
  • eNB2 302 may indicate to eNB1 301 that the UE context should be removed.
  • eNB1 301 may inform UE 303, via eNB2 302, that the macro cell is no longer the "RRC connection anchor point" and, for example, no longer a target for a connection re-establishment.
  • eNB2 302 may inform UE 303 that the macro cell is no longer the "RRC connection anchor point" and, for example, no longer the target for the connection re- establishment).
  • the information 516, 517 may be used to determine if the UE context is to be deleted from eNB1 301/moved to eNB2 302.
  • UE 303 may receive the information 515, 516 transmitted by eNB1 301 (or eNB2 302).
  • the network eNB2
  • the network may initiate additional measurements, for example, measurements on the 3G side or on another LTE macro cell frequency band, which is not needed if one is able to trust the original macro cell (with
  • RRC connection anchor point "RRC connection anchor point" coverage being there.
  • the apparatus 201 may comprise e.g. a network element (network node, e.g. a LTE-capable base station (enhanced node-B, eNB1 ) of a macro cell) may configure, in item 601 , a user terminal 303 (which may also be referred to as a user equipment UE), by transmitting a configuration message to the user terminal 303, to measure inter-frequency of the small cell (e.g. pico cell).
  • eNB1 301 may receive a measurement report from UE 303 on a measurement performed by UE 303 on a small cell (e.g. pico cell) frequency band.
  • the network may initiate a handover of UE from eNB1 301 to a network node 302 (which may comprise e.g. a LTE- capable base station (enhanced node-B, eNB2) of a small cell (e.g. a pico cell)).
  • a network node 302 which may comprise e.g. a LTE- capable base station (enhanced node-B, eNB2) of a small cell (e.g. a pico cell)).
  • a handover of UE 303 servinged by eNB1 301 (macro cell)
  • eNB2 302 small cell, e.g. pico cell
  • eNB1 301 may indicate to eNB2 302 that UE context information remains in eNB1 301 , in order eNB2 302 to transmit a configuration message to UE 303 configure UE 303 to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered if the inter-frequency neighbour becomes lower than a threshold value or if an inter-frequency neighbour offset becomes worse than that of the serving cell serving the user terminal 303.
  • eNB1 301 may receive from eNB2 302 an indication that the UE context should be removed from eNB1 301 (and eNB1 301 may perform the removal).
  • eNB1 301 may inform UE 303, via eNB2 302, that the macro cell is no longer the "RRC connection anchor point" and, for example, no longer a target for a connection re-establishment.
  • FIG. 7 is a flow chart illustrating an exemplary embodiment.
  • the apparatus 302 which may comprise e.g. a network element (network node, e.g. a LTE-capable base station (enhanced node-B, eNB2) of a small cell (which may comprise e.g. a pico cell)) may perform, in item 701 , a handover of a user terminal 303 from a network element 301 (network node, e.g. a LTE-capable base station (enhanced node-B, eNB1 ) of a macro cell, to eNB2.
  • network node e.g. a LTE-capable base station (enhanced node-B, eNB2) of a small cell (which may comprise e.g. a pico cell)
  • network element 301 network node, e.g. a LTE-capable base station (enhanced node-B, eNB1
  • a handover of UE 303 (served by eNB1 301 (macro cell)) to eNB2 302 (small cell, e.g. pico cell) is performed.
  • eNB2 302 may receive an indication from eNB1 301 that UE context information remains in eNB1 301.
  • eNB2 302 may configure UE 303, by transmitting a
  • eNB2 302 may receive from UE 303 a measurement report on a measurement performed by UE 303 on the macro cell frequency band.
  • eNB2 302 may indicate to eNB1 301 that the UE context should be removed.
  • eNB2 302 may receive, from eNB1 301 , information that the macro cell is no longer the
  • eNB2 302 may forward the information transmitted by eNB1 301 to the user terminal 303. (Alternatively, eNB2 302 may inform UE 303 that the macro cell is no longer the "RRC connection anchor point" and, for example, no longer the target for the connection re-establishment). The information may be used to determine if the UE context is to be moved to eNB2 302.
  • the network may initiate additional measurements, for example, measurements on the 3G side or on another LTE macro cell frequency band, which is not needed if one is able to trust the original macro cell (with "RRC connection anchor point") coverage being there.
  • FIG. 8 is a flow chart illustrating an exemplary embodiment.
  • the apparatus 303 which may comprise e.g. a first user equipment UE located in the service area of a radio network node 301 , 302, may receive, in item 801 , from eNB1 301 a configuration message configuring the user terminal 303 to measure inter-frequency of a small cell (e.g. pico cell).
  • the user terminal 303 may perform a measurement on a small cell (e.g. pico cell) frequency band, and transmit a corresponding measurement report to eNB1 301 .
  • a small cell e.g. pico cell
  • UE 303 may receive, from eNB2 302, a configuration message for configuring the user terminal 303 to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered if the inter- frequency neighbour becomes lower than a threshold value or if an inter-frequency neighbour offset becomes worse than that of the serving cell serving the user terminal
  • UE 303 may perform a measurement on the macro cell frequency band, and transmit a corresponding measurement report to eNB2 302.
  • UE 303 may receive from eNB1 301 via eNB2 302, information that the macro cell is no longer an "RRC connection anchor point" and, for example, no longer a target for a connection re- establishment.
  • the steps/points, signalling messages and related functions de-scribed above in Figures 1 to 8 are in no absolute chronological order, and some of the steps/points may be performed simultaneously or in an order differing from the given one. Other functions can also be executed between the steps/points or within the steps/points and other signalling messages sent be-tween the illustrated messages. Some of the steps/points or part of the steps/points can also be left out or replaced by a corresponding step/point or part of the step/point.
  • the apparatus operations illustrate a procedure that may be implemented in one or more physical or logical entities.
  • the signalling messages are only exemplary and may even comprise several separate messages for transmitting the same information. In addition, the messages may also contain other information.
  • a method comprising transmitting, from a first network apparatus of a macro cell, a configuration message to a user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of a small cell; receiving in the first network apparatus a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the small cell; initiating a handover of the user terminal from the first network apparatus to a second network apparatus of the small cell; indicating to the second network apparatus that the user terminal's context information remains in the first network apparatus, in order the second network apparatus to configure the user terminal to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receiving from the second network apparatus a message requesting the first network apparatus to remove the user terminal's context from the first network apparatus due to a macro cell
  • a method comprising informing the user terminal, via the second network apparatus, that the macro cell is no longer an RRC connection anchor point for the user terminal.
  • a method comprising, based on the received message, removing the user terminal's context from the first network apparatus.
  • a method comprising informing the user terminal, via the second network apparatus, that the macro cell is no longer a target for a connection re-establishment.
  • a method comprising performing a handover of the user terminal from a first network apparatus of a macro cell to a second network apparatus of a small cell; receiving in the second network apparatus an indication that the user terminal's context information remains in the first network apparatus; transmitting, from the second network apparatus, a configuration message to the user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a measurement trigger which is triggered, if the inter- frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receiving in the second network apparatus a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the macro cell; wherein,
  • a method comprising receiving, in a second network apparatus of a small cell, from a first network apparatus of a macro cell, information that the macro cell is no longer an RRC connection anchor point for a user terminal; forwarding the received information from the second network apparatus to the user terminal.
  • a method comprising receiving, in a user terminal from a first network apparatus of a macro cell, a configuration message in order to configure the user terminal to perform an inter-frequency
  • the method comprises transmitting to the first network apparatus a measurement report regarding the inter- frequency measurement performed in the user terminal on the frequency band of the small cell; performing a handover of the user terminal from the first network apparatus to a second network apparatus of the small cell; receiving, from the second network apparatus, a configuration message in order to configure the user terminal to perform an inter- frequency measurement on a frequency band of the macro cell; based on the receiving, performing, in the user terminal, the inter-frequency measurement on the frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; wherein, if the inter-frequency measurement performed on the frequency band of the macro cell indicates a macro cell radio link related problem in the user terminal, the method comprises transmitting to the first network apparatus a measurement report regarding the inter- frequency measurement performed in the user terminal on the frequency band of the small cell; performing a handover of the
  • a method comprising receiving, in the user terminal from the first network apparatus via the second network apparatus, information that the macro cell is no longer an RRC connection anchor point for the user terminal.
  • a method comprising initiating additional measurements in the network, if the measurement report regarding the inter-frequency measurement performed in the user terminal on the frequency band of the macro cell, indicates a macro cell radio link related problem.
  • the macro cell radio link related problem is that the user terminal is not covered by the area of the macro cell anymore.
  • the macro cell radio link related problem is that the connection between the user terminal and the first network apparatus is bad.
  • the small cell comprises a pico cell.
  • a first apparatus of a macro cell comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to transmit a configuration message to a user terminal, in order to configure the user terminal to perform an inter-frequency measurement on a frequency band of a small cell; receive a measurement report from the user terminal, regarding the inter-frequency measurement performed on the frequency band of the small cell; initiate a handover of the user terminal from the first apparatus to a second apparatus of the small cell; indicate to the second apparatus that the user terminal's context information remains in the first apparatus in order the second network apparatus to configure the user terminal to perform a new measurement to find out when the macro cell coverage disappears by enabling a measurement trigger which is triggered, if the inter-frequency neighbour becomes lower than a threshold value, or if an inter-frequency neighbour offset becomes worse than that of the cell serving the user terminal; receive from the second apparatus
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to inform the user terminal, via a second apparatus, that the macro cell is no longer an RRC connection anchor point for the user terminal.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to, based on the received message, remove the user terminal's context from the first apparatus.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the first apparatus to inform the user terminal, via the second apparatus, that the macro cell is no longer a target for a connection re-establishment.
  • a second apparatus of a small cell comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to perform a handover of a user terminal from a first apparatus of a macro cell to the second apparatus; receive an indication that the user terminal's context information remains in the first apparatus; transmit a configuration message to the user terminal, in order to configure the user terminal to perform an inter-frequency
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to based on the received measurement report, transmit a message requesting the first apparatus to remove the user terminal's context from the first apparatus.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the second apparatus to receive, from the first apparatus information that the macro cell is no longer an RRC connection anchor point for the user terminal; and forward the received information to the user terminal.
  • a terminal apparatus comprising at least one processor; and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal apparatus to receive, from a first apparatus of a macro cell, a configuration message in order to configure the terminal apparatus to perform an inter-frequency measurement on a frequency band of s small cell; based on the receiving, perform the inter-frequency measurement on the frequency band of the small cell; transmit to the first apparatus a measurement report regarding the inter-frequency measurement performed in the terminal apparatus on the frequency band of the small cell; perform a handover of the terminal apparatus from the first apparatus to a second apparatus of the small cell; receive, from the second apparatus, a configuration message in order to configure the terminal apparatus to perform an inter-frequency measurement on a frequency band of the macro cell; based on the receiving, perform the inter-frequency measurement on the frequency band of the macro cell to find out when the macro cell coverage disappears, by enabling a
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal apparatus to transmit to the second apparatus a measurement report regarding the inter-frequency measurement performed in the terminal apparatus on the frequency band of the small cell, in order the terminal apparatus's context to be removed from the first apparatus.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal apparatus to receive, from the first apparatus via the second apparatus, information that the macro cell is no longer an RRC connection anchor point for the terminal apparatus.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to initiate additional measurements in the network, if the measurement report regarding the inter-frequency measurement performed in the user terminal on the frequency band of the macro cell, indicates a macro cell radio link related problem.
  • a computer program product comprising program code means configured to perform any of the method steps when the program is run on a computer.
  • a computer-readable storage medium comprising program code means configured to perform any of the method steps when executed on a computer.

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

Abstract

Selon l'invention, un transfert d'un terminal utilisateur (303) est effectué depuis un premier appareil (301) d'une macrocellule vers un second appareil (302) d'une picocellule. Un message est transmis, du second appareil (302) ver le terminal (303), pour configurer le terminal (303) afin d'effectuer une mesure inter-fréquences sur une bande de fréquences de la macrocellule. Un rapport de mesure est reçu en provenance du terminal (303), concernant une mesure inter-fréquences effectuée. Si le rapport indique un problème radio de macrocellule, le terminal (303) est informé, via un second appareil (302), du fait que la macrocellule n'est plus un point d'ancrage RRC du terminal (303). Le second appareil (302) est informé du fait que le contexte du terminal (303) demeure dans le premier appareil (301). Le second appareil (302) demande au premier appareil (301) de supprimer le contexte du terminal du premier appareil (301).
PCT/EP2013/053228 2013-02-19 2013-02-19 Déploiement de petites cellules dans le domaine des télécommunications WO2014127797A1 (fr)

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PCT/EP2013/053228 WO2014127797A1 (fr) 2013-02-19 2013-02-19 Déploiement de petites cellules dans le domaine des télécommunications

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Publication number Priority date Publication date Assignee Title
WO2019034133A1 (fr) * 2017-08-18 2019-02-21 Huawei Technologies Co., Ltd. Gestion d'emplacement et de contexte dans un mode inactif de ran
US10893568B2 (en) 2017-08-18 2021-01-12 Huawei Technologies Co., Ltd. Location and context management in a RAN INACTIVE mode
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