WO2016116164A1 - Procédé, appareil, programme informatique et système - Google Patents

Procédé, appareil, programme informatique et système Download PDF

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Publication number
WO2016116164A1
WO2016116164A1 PCT/EP2015/051309 EP2015051309W WO2016116164A1 WO 2016116164 A1 WO2016116164 A1 WO 2016116164A1 EP 2015051309 W EP2015051309 W EP 2015051309W WO 2016116164 A1 WO2016116164 A1 WO 2016116164A1
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WO
WIPO (PCT)
Prior art keywords
base station
primary base
system frame
user equipment
data
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Application number
PCT/EP2015/051309
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English (en)
Inventor
Guillaume DECARREAU
Claudio Rosa
Per Henrik Michaelsen
Klaus Ingemann Pedersen
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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.)
Filing date
Publication date
Application filed by Nokia Solutions And Networks Oy filed Critical Nokia Solutions And Networks Oy
Priority to PCT/EP2015/051309 priority Critical patent/WO2016116164A1/fr
Publication of WO2016116164A1 publication Critical patent/WO2016116164A1/fr

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Classifications

    • 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

Definitions

  • the present application relates to a method, apparatus, computer program and system and in particular but not exclusively, some embodiments may relate to a method, apparatus and computer program for use, for example in dual connectivity scenarios.
  • a communication system can be seen as a facility that enables communication sessions between two or more entities such as fixed or mobile communication devices, base stations, servers and/or other communication nodes.
  • a communication system, and compatible communicating entities typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved.
  • the standards, specifications and related protocols can define the manner how various aspects of communication shall be implemented between communicating devices.
  • a communication can be carried on wired or wireless carriers.
  • PLMN public land mobile networks
  • wireless local networks for example wireless local area networks (WLAN).
  • a wireless system can be divided into cells or other radio coverage or service areas.
  • a radio service area is provided by a station. Radio service areas can overlap, and thus a communication device in an area can typically send signals to and receive signals from more than one station.
  • a user can access the communication system by means of an appropriate communication device.
  • a communication device of a user is often referred to as user equipment (UE) or terminal.
  • UE user equipment
  • a communication device is provided with an appropriate signal receiving and transmitting arrangement for enabling communications with other parties.
  • a communication device is used for enabling receiving and transmission of communications such as speech and data.
  • a communication device provides a transceiver station that can communicate with another communication device such as e.g. a base station or an access point and/or another user equipment.
  • the communication device may access a carrier provided by a station, for example a base station or an access node, and transmit and/or receive communications on the carrier.
  • a communication system can comprise different types of radio service areas providing transmission/reception points for the users.
  • the transmission/reception points can comprise wide area network nodes such as a macro eNode-B (eNB) which may, for example, provide coverage for an entire cell or similar radio service area.
  • eNB eNode-B
  • Network nodes can also be small or local radio service area network nodes, for example Home eNBs (HeNB), pico eNodeBs (pico-eNB), or femto nodes. Some applications utilise radio remote heads (RRH) that are connected to for example an eNB.
  • the smaller radio service areas can be located wholly or partially within the larger radio service area. A user equipment may thus be located within, and thus communicate with, more than one radio service area.
  • the nodes of the smaller radio service areas may be configured to support local offload.
  • the local nodes can also, for example, be configured to extend the range of a cell.
  • a method comprising: receiving, at a secondary base station, information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; receiving system frame information at the secondary base station; and using said system frame information to control when to change from communicating with said first primary base station and communicating with said second primary base station.
  • the method comprises causing data to be transmitted to the user equipment using a first security key when communicating with the first primary base station and causing data to be transmitted to the user equipment using a second security key when communicating with the second primary base station.
  • said data comprises packet data convergence protocol packet data units.
  • the method comprises: causing status information to be sent to the second primary base station.
  • said status information indicates at least one of: whether packet data convergence protocol packet data units have been correctly sent to the user equipment; whether packet data convergence protocol packet data units have been correctly received at the user equipment.
  • the method comprises using said system frame information to control when to reset media access control with the user equipment,
  • the method comprises using said system frame information to control when to re-establish radio link control with the user equipment.
  • said system frame information comprises a system frame number.
  • a computer program comprising computer executable instructions which when run on one or more processors perform the method of the first aspect.
  • an apparatus comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; receive system frame information; and use said system frame information to control when to change from communicating with said first primary base station and communicating with said second primary base station.
  • the apparatus is configured to cause data to be transmitted to the user equipment using a first security key when communicating with the first primary base station, and to cause data to be transmitted to the user equipment using a second security key when communicating with the second primary base station.
  • said data comprises packet data convergence protocol packet data units.
  • the apparatus is configured to cause status information to be sent to the second primary base station.
  • said status information indicates at least one of: whether packet data convergence protocol packet data units have been correctly sent to the user equipment; whether packet data convergence protocol packet data units have been correctly received at the user equipment.
  • the apparatus is configured to use said system frame information to control when to reset media access control with the user equipment.
  • the apparatus is configured to use said system frame information to control when to re-establish radio link control with the user equipment.
  • said system frame information comprises a system i o frame number.
  • an apparatus comprising: means for receiving information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; 15 means for receiving system frame information; and means for using said system frame information to control when to change from communicating with said first primary base station and communicating with said second primary base station.
  • the apparatus comprises means for causing data 2 0 to be transmitted to the user equipment using a first security key when communicating with the first primary base station, and means for causing data to be transmitted to the user equipment using a second security key when communicating with the second primary base station.
  • said data comprises packet data convergence protocol packet data units.
  • the apparatus comprises means for causing status information to be sent to the second primary base station.
  • said status information indicates at least one of: whether packet data convergence protocol packet data units have been correctly sent to the user equipment; whether packet data convergence protocol packet data units have been correctly received at the user equipment.
  • the apparatus comprises means for using said 5 system frame information to control when to reset media access control with the user equipment.
  • the apparatus comprises means for using said system frame information to control when to re-establish radio link control with the i o user equipment.
  • said system frame information comprises a system frame number.
  • a method comprising: sending, to a secondary base station, information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; sending system frame information to the secondary base station; and said system frame information for use in controlling when to change
  • said system frame information comprises a system frame number.
  • a computer program comprising computer executable instructions which when run on one or more processors perform the method of the fifth aspect.
  • an apparatus comprising at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: send, to a secondary base station, information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; send system frame information to the secondary base station; and said system frame information for use in controlling when to change from communicating with said first primary base station and communicating with said second primary base station.
  • said system frame information comprises a system frame number.
  • an apparatus comprising: means for sending, to a secondary base station, information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place; means for sending system frame information to the secondary base station; and said system frame information for use in controlling when to change from communicating with said first primary base station and communicating with said second primary base station.
  • said system frame information comprises a system frame number.
  • a ninth aspect there is provided a method comprising: receiving, at a user equipment, information from a first primary base station, said information indicating handover of the user equipment to a second primary base station is to take place; receiving system frame information at the user equipment; and using said system frame information to control when to change a security configuration for data transmission from the user equipment to a secondary base station.
  • the method comprises: transmitting from the user equipment according to a first split configuration first user data of a radio access network layer to the first primary base station and second user data of the radio access network layer to the secondary base station; and transmitting after receiving the information indicating handover of the user equipment to the second primary base station all user data of the radio access network layer to the secondary base station; wherein the first user data comprise at least a part of the user data of the radio access network layer.
  • the method comprises: changing the security configuration; and transmitting from the user equipment according to a second split configuration third user data of the radio access network layer to the second primary base station and forth user data of the radio access network layer to the secondary base station; wherein the third user data comprise at least a part of the user data of the radio access network layer.
  • said radio access network layer is the packet convergence protocol packet layer.
  • the second split configuration between the second primary base station and the secondary base station corresponds to the first split configuration between the first primary base station and the secondary base station.
  • a computer program comprising computer executable instructions which when run on one or more processors perform the method of the ninth aspect.
  • an apparatus comprising at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: receive information from a first primary base station, said information indicating handover of the apparatus to a second primary base station is to take place; receive system frame information; and use said system frame information to control when to change a security configuration for data transmission from the apparatus to a secondary base station.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus further to: transmit according to a first split configuration first user data of a radio access network layer to the first primary base station and second user data of the radio access network layer to the secondary base station; and transmit after receiving the information indicating handover of the apparatus to the second primary base station all user data of the radio access network layer to the secondary base station; wherein the first user data comprise at least a part of the user data of the radio access network layer.
  • the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus further to: change the security configuration; and transmit according to a second split configuration third user data of the radio access network layer to the second primary base station and forth user data of the radio access network layer to the secondary base station; wherein the third user data comprise at least a part of the user data of the radio access network layer.
  • said radio access network layer is the packet convergence protocol packet layer.
  • the second split configuration between the second primary base station and the secondary base station corresponds to the first split configuration between the first primary base station and the secondary base station.
  • said system frame information comprises a system frame number.
  • Figure 1 shows a schematic diagram of a network according to some embodiments
  • Figure 2 shows a schematic diagram of a mobile communication device according to some embodiments
  • Figure 3 shows a first example of a UE connected to two base stations
  • Figure 4 shows a second example of a UE connected to two base stations
  • Figure 5 is a flowchart of a method of a base station according to an embodiment
  • Figure 6 is a flowchart of a method of a user equipment according to an embodiment
  • Figure 7 is a signalling diagram according to an embodiment
  • Figure 8 shows a schematic diagram of a control apparatus according to some embodiments. Detailed description
  • a wireless communication system mobile communication devices or user equipment (UE) 102, 103, 105 are provided wireless access via at least one base station or similar wireless transmitting and/or receiving node or point.
  • UE user equipment
  • FIG. 1 example two overlapping access systems or radio service areas of a cellular system 100 and 1 10 and three smaller radio service areas 1 15, 1 17 and 1 1 9 provided by base stations 106, 107, 1 16, 1 18 and 1 20 are shown.
  • Each mobile communication device and station may have one or more radio channels open at the same time and may send signals to and/or receive signals from more than one source.
  • the radio service area borders or edges are schematically shown for illustration purposes only in Figure 1 . It shall also be understood that the sizes and shapes of radio service areas may vary considerably from the shapes of Figure 1 .
  • a base station site can provide one or more cells.
  • a base station can also provide a plurality of sectors, for example three radio sectors, each sector providing a cell or a subarea of a cell. All sectors within a cell can be served by the same base station.
  • Base stations are typically controlled by at least one appropriate controller apparatus so as to enable operation thereof and management of mobile communication devices in communication with the base stations.
  • control apparatus 108 and 109 is shown to control the respective macro level base stations 106 and 107.
  • the control apparatus of a base station can be interconnected with other control entities.
  • the control apparatus is typically provided with memory capacity and at least one data processor.
  • the control apparatus and functions may be distributed between a plurality of control units.
  • the control apparatus may be as shown in Figure 8 which is discussed later.
  • stations 106 and 107 are shown as connected to a serving gateway (SGW) 1 12.
  • SGW serving gateway
  • the smaller stations 1 16, 1 18 and 1 20 are connected to a further gateway function 1 1 1 which is connected to the S-GW 1 12.
  • the further gateway function 1 1 1 is omitted.
  • the S-GW 1 12 may be connected to, for example, the internet 134 via a PGW (PDN (packet data network) gateway) 1 32.
  • PGW packet data network gateway
  • User data packets like internet protocol (IP) packets, may be mapped to bearers (radio bearers) in the radio access network (RAN). This mapping may be based Quality-of-Service requirements of the data packets.
  • IP internet protocol
  • the base stations are also connected to a MME 1 36 (mobility management entity) which in turn is connected to a HSS (home subscriber server) 1 38.
  • MME 1 36 mobility management entity
  • HSS home subscriber server
  • a possible mobile communication device for transmitting and retransmitting information blocks towards the stations of the system will now be described in more detail with reference to Figure 2 showing a schematic, partially sectioned view of a communication device 200.
  • a communication device is often referred to as user equipment (UE) or terminal.
  • An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals.
  • Non- limiting examples include a mobile station (MS) such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card or other wireless interface facility, personal data assistant (PDA) provided with wireless communication capabilities, or any combinations of these or the like.
  • MS mobile station
  • PDA personal data assistant
  • a mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content include downloads, television and radio programs, videos, advertisements, various alerts and other information.
  • the mobile device 200 may receive signals over an air interface 207 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals.
  • transceiver apparatus is designated schematically by block 206.
  • the transceiver apparatus 206 may be provided for example by means of a radio part and associated antenna arrangement.
  • the antenna arrangement may be arranged internally or externally to the mobile device.
  • a wireless communication device can be provided with a Multiple Input / Multiple Output (MIMO) antenna system.
  • MIMO arrangements as such are known. MIMO systems use multiple antennas at the transmitter and receiver along with advanced digital signal processing to improve link quality and capacity.
  • multiple antennas can be provided, for example at base stations and mobile stations, and the transceiver apparatus 206 of Figure 2 can provide a plurality of antenna ports. More data can be received and/or sent where there are more antenna elements.
  • a station may comprise an array of multiple antennas. Signalling and muting patterns can be associated with Tx antenna numbers or port numbers of MIMO arrangements.
  • a mobile device is also typically provided with at least one data processing entity 201 , at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices.
  • the data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204.
  • the user may control the operation of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like.
  • a display 208, a speaker and a microphone can be also provided.
  • a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.
  • the communication devices 1 02, 103, 105 can access the communication system based on various access techniques, such as code division multiple access (CDMA), or wideband CDMA (WCDMA).
  • CDMA code division multiple access
  • WCDMA wideband CDMA
  • Other examples include time division multiple access (TDMA), frequency division multiple access (FDMA) and various schemes thereof such as the interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA) and so on.
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • IFDMA interleaved frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SDMA space division multiple access
  • Dual connectivity is a feature currently under standardization for Rel-12 of the 3GGP EUTRA specifications.
  • the basic principle of DC is that a UE is able to simultaneously receive/transmit data from/to two eNBs, a master eNB (MeNB) and a secondary eNB (SeNB), operating at different carrier frequencies.
  • the main difference between DC and carrier aggregation (CA) is that the MeNB and the SeNB are assumed to be connected via a non-ideal backhaul link (X2) characterized by transmission delays (in the range of -2-30 ms) and limited capacity.
  • X2 non-ideal backhaul link
  • X2 non-ideal backhaul link
  • X2 non-ideal backhaul link
  • X2 non-ideal backhaul link
  • U-plane user plane
  • Bearer split refers to the ability to split a bearer over multiple eNBs. Without bearer split, a bearer is only transmitted by one eNB. From C-plan
  • Figure 3 shows a first arrangement of a RAN protocol architecture.
  • the first eNode B is referred to as a MeNode B (the master eNode B).
  • the master eNode B is the eNode B which terminates at least the S1 - MME for a given UE and may act as a mobility anchor towards the core network.
  • the MeNB may always have at least one bearer established for a given UE - this may be mandatory since the SRBs (signalling radio bearers) always go to MeNB, in some systems. However, DRBs (data radio bearer) may all be offloaded to SeNB.
  • the second eNode B is the SeNode B (secondary eNode B) which provides additional radio resources for the user equipment and which is not the master eNode B.
  • dual connectivity is provided where a given user equipment consumes radio resources provided by at least two different network points (e.g. the master and secondary eNode Bs).
  • Each of the eNode Bs in Figure 3 comprises a PDCP (packet data convergence protocol) layer, a RLC (radio link control) layer and a MAC (medium access control) layer.
  • Figure 4 shows an alternative arrangement to that shown in Figure 3.
  • the master eNode B terminates S1 -U interface for the UE in question.
  • a bearer split in the master eNode B also a non-split bearer is shown for completeness.
  • both of the base stations have independent RLC layers for a split bearer.
  • the data stream for a split bearer is received at the master eNode B.
  • the data is received from an S-GW.
  • One part of the stream is passed by the RLC and MAC layers to the user equipment and the other part is passed by a back haul connection between the master eNode B and secondary eNode B to the RLC layer of the secondary eNode B.
  • the stream then passes through the MAC layer of the secondary eNode B to the user equipment UE.
  • the handover (HO) procedure is not supported while the UE is in DC between a MeNB and a SeNB. That means, the secondary cell group (SCG), i.e. the group of cells served by the SeNB, is to be released before/during the HO procedure and can be added for the corresponding UE only after the HO procedure is successfully completed.
  • the selected HO procedure for Rel-12 DC has some disadvantages. First of all, releasing the SCG might result in an unnecessary interruption of data transmission from the SeNB when only the MeNB needs to be changed. Also, during the HO procedure U-plane data might be unnecessarily transmitted back and forward between SeNB, target eNB and/or source (M)eNB. For example, in case of a split bearer the same data might first be forwarded from source (M)eNB to SeNB, then from source (M)eNB to target eNB, and then again from target (M)eNB to SeNB.
  • a solution has been proposed where the UE is informed of the first packet data convergence protocol (PDCP) sequence number (SN) starting from which the new security key (i.e. the security key used in the target eNB) is to be applied.
  • PDCP packet data convergence protocol
  • SN sequence number
  • PDUs PDCP protocol data units
  • a UE is required to simultaneously handle multiple security keys (at least for a certain period of time during/after HO).
  • transmissions from the target MeNB can be delayed until the SeNB has transmitted the last PDCP SN using the "old" security key.
  • this may delay potential transmissions from the target eNB, and may require additional signaling to indicate to the target eNB when the UE is ready to receive PDCP PDUs encrypted using the new security key.
  • the method provided aims to overcome the problem of how to synchronize transmissions from SeNB and target MeNB using new security key after HO procedure.
  • Figure 5 shows a flowchart of a proposed method.
  • the method comprises receiving, at a secondary base station, information from a first primary base station, said information indicating handover of a user equipment to a second primary base station is to take place, receiving system frame information at the secondary base station and using said system frame information to control when to change from communicating with said first primary base station and communicating with said second primary base station.
  • the secondary base station may be referred to as a SeNB
  • the first and second primary base stations may be referred to as a source eNB and a target eNB respectively.
  • System frame information may comprise a system frame number (SFN) as specified for LTE or LTE-Advanced.
  • SFN system frame number
  • the UE and the SeNB (and potentially also the target eNB) can be informed of the system frame number (SFN) up to which the SeNB can continue downlink (DL) data transmission of already forwarded PDCP PDUs encrypted using the "old" security key (i.e. the security key in the source eNB).
  • the SeNB can continue transmitting buffered data.
  • the SeNB and the UE can reset/re-establish MAC/RLC (i.e. buffers are flushed).
  • UE may also re-establish PDCP and the SeNB can transmit to the target eNB a PDCP status report, so that the target eNB knows which of the PDCP PDUs (forwarded by the source eNB) needs to be retransmitted.
  • the source eNB may transmit the status report to the target eNB as part of the HO procedure.
  • the status report may include e.g. the SNs of the PDCP PDUs delivered to SeNB and for which the source eNB has not yet received from the SeNB an indication of successful delivery to the UE.
  • the source eNB stops forwarding U-plane data to the SeNB.
  • Figure 6 shows a flowchart of a proposed method.
  • the method comprises receiving, at a user equipment, information from a first primary base station, said information indicating handover of the user equipment to a second primary base station is to take place, receiving system frame information at the secondary base station and using said system frame information to control when to change the security configuration for uplink (UL) data transmission from the user equipment to the secondary base station.
  • UL uplink
  • the secondary base station may be referred to as a SeNB
  • the first and second primary base stations may be referred to as a source eNB and a target eNB, respectively.
  • System frame information may comprise a system frame number (SFN) as specified for LTE or LTE-Advanced.
  • the security configuration may comprise a security key for encryption of PDCP PDUs.
  • a first security key may be associated with the source eNB, and a second security key may be associated with the target eNB.
  • the UE and the SeNB can be informed of the system frame number (SFN) up to which the UE is allowed to continue transmission of PDCP PDUs encrypted using the first security key associated with the source eNB.
  • SFN system frame number
  • the UE can continue transmitting buffered data.
  • the UE and the SeNB can reset/re-establish MAC/RLC (i.e. buffers are flushed).
  • the UE can continue data transmission of PDCP PDUs towards the SeNB using the second security key associated with the target eNB.
  • the UE may automatically switch the UL data from the MeNB to the SeNB after receiving information indicating a handover to the target eNB.
  • a split bearer is configured for U-plane data transmission in uplink
  • the UE may automatically switch the UL data of the split bearer towards the MeNB from the MeNB to the SeNB after receiving information indicating a handover to the target eNB.
  • the UE may continue UL data transmission towards the SeNB after receiving information indicating a handover to the target eNB.
  • the SeNB may continue forwarding of UL PDCP PDUS to the source eNB until the SFN indicated.
  • the UE may start using the second security key (associated with the target eNB), and may continue transmission of PDCP PDUs towards the SeNB, Further, the SeNB may start forwarding of UL PDCP PDUs received from the UE to the target eNB at said SFN.
  • the second security key associated with the target eNB
  • the UE may automatically start switching or redirecting the UL data from the SeNB to the target eNB (new MeNB) at said SFN.
  • the UE may automatically start switching or redirecting at least a part of the UL data from the SeNB to the MeNB at said SFN.
  • the UE may, in particular, establish the split bearer between the target eNB and the SeNB as configured before the HO procedure between the source eNB (old MeNB) and the SeNB.
  • Figure 7 shows an example of the messages exchanged between a target MeNB, source MeNB, SeNB and UE during which the methods of Figures 5 and 6 may be performed.
  • the source (M)eNB can inform the target (M)eNB of the SFN up to which the SeNB is allowed to transmit to the UE DL PDCP PDUs encrypted using the source eNB security key, and up to which the UE is allowed to transmit to the SeNB UL PDCP PDUs encrypted using the source eNB security key.
  • the source (M)eNB informs the SeNB and the UE (respectively) of the SFN up to which the SeNB is allowed to transmit to the UE DL PDCP PDUs encrypted using the source eNB security key, and up to which the UE is allowed to transmit to the SeNB UL PDCP PDUs encrypted using the source eNB security key.
  • the target eNB may start setup of X2 connection with the SeNB (1 b). This may be initiated by the target MeNB but also from the SeNB upon reception of the HO indication (2a) from the source eNB. In some implementations of the proposed method the setup of X2 connection initiated by the target eNB may substitute the HO indication message (2a) from source MeNB to SeNB.
  • the source eNB stops forwarding DL PDCP PDUs to the SeNB.
  • the SeNB replies to the HO indication message (2a) with a SN status report (5a).
  • the UE may automatically switch the UL data transmission from the MeNB to the SeNB after receiving the HO command (2b), in case a split bearer or transmission towards MeNB only was configured for U-plane data transmission in uplink.
  • the SeNB may continue forwarding of UL PDCP PDUS to the source eNB until SFN #X is reached.
  • the source eNB may start forwarding DL data to the target eNB (6), including a status report indicating the SN of the PDCP PDUs delivered to the SeNB and for which the source eNB did not yet receive from the SeNB an indication of successful delivery to the UE (5b).
  • the SeNB can continue scheduling to the UE DL PDCP PDUs delivered from the source eNB until SFN indicated by the source MeNB (SFN #X).
  • SFN #X the UE and the SeNB reset MAC and re-establish RLC for DL data transmission.
  • the UE also re-establishes PDCP connection since a new security key is to be taken into use for data exchange with the SeNB and the target eNB.
  • the SeNB may send to the target eNB a status report indicating e.g. the SN of the DL PDCP PDUs for which the SeNB did not yet receive from the UE an indication of successful delivery.
  • the UE may start using the second security key associated with the target eNB for UL data transmission, and may continue transmission of UL PDCP PDUs towards the SeNB, Further, the SeNB may start forwarding of UL PDCP PDUs received from the UE to the target eNB at SFN #X.
  • the UE may automatically start switching or redirecting the UL data from the SeNB to the target eNB (new MeNB) at said SFN.
  • the UE may automatically start switching or redirecting at least a part of the UL data from the SeNB to the MeNB at said SFN.
  • the UE may, in particular, re-establish the split bearer as configured before the HO procedure.
  • the SeNB can start scheduling to the UE DL PDCP PDUs delivered from the target eNB.
  • target eNB can start scheduling to the UE DL data forwarded by the source eNB (6), as well as DL data directly delivered by the S- GW after path switch).
  • the target eNB is not informed of the SFN up to which the SeNB is allowed to transmit DL PDCP PDUs encrypted using the security key in the source eNB.
  • the target eNB may use the status report received from the SeNB (indicating e.g. the SN of the DL PDCP
  • the proposed method may be suitable for use in synchronized networks where the MeNB and the SeNB are SFN synchronized. More specifically, it may be suitable in case of synchronized HO procedure where the UE and the target eNB are informed of the exact SFN when the HO becomes effective and no additional synchronized procedure (random access procedure) between UE and target eNB is needed.
  • the SFN up to which the SeNB can continue transmission of PDCP PDUs encrypted using the source eNB security key may be the same as the SFN when handover should be applied, or alternatively the SFN when handover should be applied minus a predefined offset value.
  • the source eNB might signal this offset value to the SeNB, UE and potentially also target eNB (instead of the absolute value of the SFN).
  • the RA procedure as well as the indication of HO completion to the target eNB may only be needed in case of "unsynchronized" handover procedure.
  • FIG. 8 shows an example of a control apparatus for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a base station or (e) node B, or a server or host.
  • base stations comprise a separate apparatus unit or module.
  • the control apparatus can be another network element such as a radio network controller or a spectrum controller.
  • each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller.
  • the control apparatus 300 can be arranged to provide control on communications in the service area of the system.
  • the control apparatus 300 can be arranged to provide control on communications in the service area of the system.
  • the control apparatus 300 can be arranged to provide control on communications in the service area of the system.
  • control apparatus 300 comprises at least one memory 301 , at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. The receiver and/or the transmitter may be implemented as a radio front end or a remote radio head. For example the control apparatus 300 can be configured to execute an appropriate software code to provide the control functions.
  • Figure 8 shows one memory
  • any number of these components may be provided. Multiple functions may be carried out in a single processor, or separate functions may be carried out by separate processors. For example a single processor may be used to make multiple determinations, or separate determinations may be made by separate processors.
  • the apparatuses may include or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception.
  • the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities. It is noted that whilst embodiments have been described in relation to LTE, similar principles can be applied to any other communication system or radio access technology, where dual connectivity is supported. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.
  • the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
  • Embodiments as described above by means of figures 1 to 7 may be implemented by computer software executable by a data processor, at least one data processing unit or process of a device, such as a base station, e.g. eNB, or a UE, in, e.g., the processor entity, or by hardware, or by a combination of software and hardware.
  • Computer software or program also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium or distribution medium and they include program instructions to perform particular tasks.
  • An apparatus-readable data storage medium or distribution medium may be a non-transitory medium.
  • a computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out embodiments.
  • the one or more computer-executable components may be at least one software code or portions of it.
  • any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions.
  • the software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.
  • the physical media is a non-transitory media.
  • the memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.
  • the data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.
  • Embodiments described above in relation to figures 1 to 7 may be practiced in various components such as integrated circuit modules.
  • the design of integrated circuits is by and large a highly automated process.
  • Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

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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 consistant : à recevoir, au niveau d'une station de base secondaire, des informations en provenance d'une station de base primaire, lesdites informations indiquant qu'un transfert intercellulaire d'un équipement utilisateur à une seconde station de base primaire doit avoir lieu ; à recevoir des informations de trame de système au niveau de la station de base secondaire ; et à utiliser lesdites informations de trame de système pour commander le moment de changement entre une communication avec ladite première station de base primaire et une communication avec ladite seconde station de base primaire.
PCT/EP2015/051309 2015-01-23 2015-01-23 Procédé, appareil, programme informatique et système WO2016116164A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107889234A (zh) * 2016-09-30 2018-04-06 夏普株式会社 一种数据转发的方法及其设备

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
BROADCOM CORPORATION: "Method to use SCG during MCG handover for Dual Connectivity", vol. RAN WG2, no. Prague, Czech Republic; 20140210 - 20140214, 9 February 2014 (2014-02-09), XP050791876, Retrieved from the Internet <URL:http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN2/Docs/> [retrieved on 20140209] *
KYOCERA: "Handover enhancements with dual connectivity", vol. RAN WG2, no. Prague, Czech Republic; 20140210 - 20140214, 9 February 2014 (2014-02-09), XP050791998, Retrieved from the Internet <URL:http://www.3gpp.org/ftp/Meetings_3GPP_SYNC/RAN2/Docs/> [retrieved on 20140209] *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107889234A (zh) * 2016-09-30 2018-04-06 夏普株式会社 一种数据转发的方法及其设备

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