WO2020095804A1 - Réseau et procédés pour prendre en charge une mobilité inter-domaine dans un réseau d'accès radio virtualisé - Google Patents

Réseau et procédés pour prendre en charge une mobilité inter-domaine dans un réseau d'accès radio virtualisé Download PDF

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WO2020095804A1
WO2020095804A1 PCT/JP2019/042683 JP2019042683W WO2020095804A1 WO 2020095804 A1 WO2020095804 A1 WO 2020095804A1 JP 2019042683 W JP2019042683 W JP 2019042683W WO 2020095804 A1 WO2020095804 A1 WO 2020095804A1
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radio access
access network
wireless terminal
distributed unit
unit
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PCT/JP2019/042683
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English (en)
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Kamel M. Shaheen
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Sharp Kabushiki Kaisha
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/36—Reselection control by user or terminal equipment
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/34—Reselection control
    • H04W36/38—Reselection control by fixed network equipment

Definitions

  • the technology relates to wireless communications, and particularly to radio access network architecture and operation.
  • a radio access network typically resides between wireless devices, such as user equipments (UEs), mobile phones, mobile stations, or any other device having wireless termination, and a core network.
  • UEs user equipments
  • Example of radio access network types includes the GRAN, GSM radio access network; the GERAN, which includes EDGE packet radio services; UTRAN, the UMTS radio access network; E-UTRAN, which includes Long-Term Evolution; and g-UTRAN, the New Radio (NR) .
  • a radio access network may comprise one or more access nodes, such as base station nodes, which facilitate wireless communication or otherwise provides an interface between a wireless terminal and a telecommunications system.
  • a non-limiting example of a base station can include, depending on radio access technology type, a Node B (“NB”), an enhanced Node B (“eNB”), a home eNB (“HeNB”), a gNB (for a New Radio [“NR”] technology system), or some other similar terminology.
  • the 3rd Generation Partnership Project (“3GPP”) is a group that, e.g., develops collaboration agreements such as 3GPP standards that aim to define globally applicable technical specifications and technical reports for wireless communication systems.
  • 3GPP documents may describe certain aspects of radio access networks.
  • Overall architecture for a fifth generation system e.g., the 5G System, also called “NR” or “New Radio”, as well as “NG” or “Next Generation”, is shown in Fig. 1, and is also described in 3GPP TS 38.300.
  • the 5G NR network is comprised of NG RAN (Next Generation Radio Access Network) and 5GC (5G Core Network).
  • NGRAN is comprised of gNBs (e.g., 5G Base stations) and ng-eNBs (i.e. LTE base stations).
  • An Xn interface exists between gNB-gNB, between (gNB)-(ng-eNB) and between (ng-eNB)-(ng-eNB).
  • the Xn is the network interface between NG-RAN nodes.
  • Xn-U stands for Xn User Plane interface
  • Xn-C stands for Xn Control Plane interface.
  • ANG interface exists between 5GC and the base stations (i.e. gNB & ng-eNB).
  • a gNB node provides NR user plane and control plane protocol terminations towards the UE, and is connected via the NG interface to the 5GC.
  • the 5G NR New Radio
  • the 5G NR is connected to AMF (Access and Mobility Management Function) and UPF (User Plane Function) in 5GC (5G Core Network).
  • the protocol layers are mapped into three units: RRH (Remote Radio Head), DU (Distributed Unit) and CU (Central Unit) as shown in Fig. 2.
  • Fig. 2 also shows the user plane (UP) protocol stack for New Radio and the control plane (CP) protocol stack for New Radio.
  • UP user plane
  • CP control plane
  • NFV Network Functions Virtualizations
  • NFV Network Functions Virtualizations
  • NFV aims to consolidate many network equipment types onto industry standard high volume servers, switches and storage, which could be located in Datacentres, Network Nodes, and in the end user premises, as illustrated in Fig. 3.
  • NFV involves the implementation of network functions in software that can run on a range of industry standard server hardware, and that can be moved to, or instantiated in, various locations in the network as required, without the need for installation of new equipment. See, e.g., “Network Functions Virtualizations-Introductory White Paper” (PDF). ETSI. 22 October 2012. Retrieved 20 June 2013.
  • PDF Network Functions Virtualizations-Introductory White Paper
  • Radio access network nodes are one of the network elements that may be included in a NFV approach.
  • 3GPP is working on defining new generation networks that utilize “Network Function Virtualization” or NFV, such as NFV key elements and key requirements for a fifth generation system, e.g., the 5G System, also called “NR” or “New Radio”, as well as “NG” or “Next Generation”.
  • NFV Network Function Virtualization
  • 5G System also called “NR” or “New Radio”
  • NG Next Generation
  • 3GPP TS 38.913 states that RAN architecture shall allow deployments using Network Function Virtualization
  • 3GPP TS 38.801 states that NR shall allow Centralized Unit (CU) deployment with Network Function virtualization (NFV)’
  • 3GPP TS 38.401 defines a Network Function as "a logical node within a network infrastructure that has well-defined external interfaces and well-defined functional behavior.”
  • a central UP entity For NG-RAN (including all dual- and multi-connectivity scenarios), such a central UP entity would provide UP interface termination points (i.e. NG-U, Xn-U and F1-U), provide resources for instantiating protocol entities (e.g. GTP-U, SDAP, PDCP), and would provide access to these resources via a control interface towards a logical CP node.
  • the control interface would be the E1 interface (CP only) in case of gNB-CU. If the gNB-CU is implemented as a single logical node (i.e. no CP-UP split is deployed), then such interface would be internal to the gNB-CU.
  • FIG. 4 shows a Network Function Virtualization (NFV) scheme for 5G New Radio, wherein a shared central unit/user plane entity, CU-UP, is connected across an E1 interface to plural control plane units, CU-CP gNB .
  • NFV Network Function Virtualization
  • a radio access network comprising: a radio access network source node central unit; a radio access network target node central unit; a radio access network source node distributed unit connected with the radio access network source node central unit over a first packet data domain; a radio access network target node distributed unit connected with the radio access network target node central unit over a second packet data domain; a wireless terminal configured to communication across a radio interface with one or both of the radio access network source node distributed unit and the radio access network target node distributed unit; and processor circuitry configured to change at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • a radio access network source node central unit comprising: an interface to radio access network source node distributed unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; an interface to radio access network target node central unit which is connected to a radio access network target node distributed unit via a second packet data domain; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • a radio access network source node distributed unit comprising: an interface to radio access network source node central unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; transceiver circuitry configured to transmit and receive communications over a radio interface with the wireless terminal; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to radio access network target node distributed unit, the radio access network target node distributed unit being connected to radio access network target node central unit via a second Packet data domain.
  • a wireless terminal comprising: an interface to radio access network source node central unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; transceiver circuitry configured to transmit and receive communications over a radio interface with radio access network source node distributed unit and radio access network target node distributed unit, the radio access network source node distributed unit being connected by a first packet data domain to radio access network source node central unit; the radio access network target node distributed unit being connected by a second Packet data domain to radio access network target node central unit; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to radio access network target node distributed unit.
  • a method in a radio access network comprising: making a determination that a wireless terminal should be handed over from radio access network source node distributed unit to radio access network target node distributed unit, the radio access network source node distributed unit being connected to radio access network source node central unit over a first packet data domain, the radio access network target node distributed unit being connected to radio access network target node central unit over a second packet data domain in accordance with the determination, changing at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit and thereby routing control plane signaling for the wireless terminal through the second packet data domain.
  • Fig. 1 is a diagrammatic view of overall architecture for a 5G New Radio system.
  • Fig. 2 is a diagrammatic view showing gNB interface types for the 5G New Radio system of Fig. 1.
  • Fig. 3 is a diagrammatic view showing a migration from a classical network appliance approach to a network virtualization approach.
  • Fig. 4 is a schematic view of an example Network Function Virtualization (NFV) scheme for 5G New Radio.
  • NFV Network Function Virtualization
  • FIG. 5 is a schematic view of an example embodiment of a communications system including a virtualized radio access network which supports inter-domain mobility.
  • Fig. 6 is a schematic view of an example embodiment of a wireless terminal which connects to a core network through the virtualized radio access network of Fig. 5.
  • Fig. 7 is a diagrammatic view showing how a radio access network node distributed unit may be distributed to plural sites.
  • Fig. 8 is a diagrammatic view of showing hierarchy of various protocols in the context of various layers of the Open Systems Interconnection (OSI) model.
  • Fig. 9 is a flowchart showing example, basic, representative acts or steps performed by the radio access network of Fig. 5 according to a basic embodiment and mode.
  • FIG. 10 is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig. 5, wherein the handover procedure is based on a radio access network node central unit.
  • Fig. 11 is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig. 5, wherein the handover procedure is based on a wireless terminal.
  • Fig. 12 and is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig. 5, wherein the handover procedure is based on a radio access network node distributed unit but a wireless terminal makes a determination that the handover should occur.
  • Fig. 13 and is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig.
  • Fig. 14 is a signal flow diagram showing an inter-control unit connected mode handover/cell re-selection procedure for the radio access network of Fig. 5.
  • Fig. 15 is a diagrammatic view showing example elements comprising electronic machinery which may comprise a wireless terminal, a radio access node, and a core network node according to an example embodiment and mode.
  • the technology disclosed herein concerns a radio access network and method of operating same, as well as entities or units of the radio access network and method of operating the entities or units.
  • the radio access network may be a virtualized radio access network comprising a radio access network source node central unit; a radio access network target node central unit; a radio access network source node distributed unit; a radio access network target node distributed unit; a wireless terminal; and change of connectivity controlling processor circuitry.
  • the radio access network source node distributed unit is connected with the radio access network source node central unit over a first packet data domain.
  • the radio access network target node distributed unit is connected with the radio access network target node central unit over a second packet data domain.
  • the wireless terminal is configured to communication across a radio interface with one or both of the radio access network source node distributed unit and the radio access network target node distributed unit.
  • the change of connectivity controlling processor circuitry is configured to change at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • core network can refer to a device, group of devices, or sub-system in a telecommunication network that provides services to users of the telecommunications network. Examples of services provided by a core network include aggregation, authentication, call switching, service invocation, gateways to other networks, etc.
  • wireless terminal can refer to any electronic device used to communicate voice and/or data via a telecommunications system, such as (but not limited to) a cellular network.
  • a telecommunications system such as (but not limited to) a cellular network.
  • Other terminology used to refer to wireless terminals and non-limiting examples of such devices can include user equipment terminal, UE, mobile station, mobile device, access terminal, subscriber station, mobile terminal, remote station, user terminal, terminal, subscriber unit, cellular phones, smart phones, personal digital assistants (“PDAs”), laptop computers, tablets, netbooks, e-readers, wireless modems, etc.
  • PDAs personal digital assistants
  • the term “access node”, “node”, or “base station” can refer to any device or group of devices that facilitates wireless communication or otherwise provides an interface between a wireless terminal and a telecommunications system.
  • a non-limiting example of a base station can include, in the 3GPP specification, a Node B (“NB”), an enhanced Node B (“eNB”), a home eNB (“HeNB”), a gNB (for a New Radio [“NR”] technology system), or some other similar terminology.
  • telecommunication system or “communications system” can refer to any network of devices used to transmit information.
  • a non-limiting example of a telecommunication system is a cellular network or other wireless communication system.
  • the term “cellular network” or “cellular radio access network” can refer to a network distributed over cells, each cell served by at least one fixed-location transceiver, such as a base station.
  • a “cell” may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced (“IMTAdvanced”). All or a subset of the cell may be adopted by 3GPP as licensed bands (e.g., frequency band) to be used for communication between a base station, such as a Node B, and a UE terminal.
  • a cellular network using licensed frequency bands can include configured cells. Configured cells can include cells of which a UE terminal is aware and in which it is allowed by a base station to transmit or receive information. Examples of cellular radio access networks include E-UTRAN, and any successors thereof (e.g., NUTRAN).
  • Fig. 5 illustrates a telecommunication network 20 which comprises core network 22 and virtualized virtualized radio access network 24.
  • the core network 22 is illustrated as being a 5G core network, and thus the virtualized virtualized radio access network 24 is shown as connected to core network 22 over an interface labeled as the NG interface.
  • the virtualized radio access network 24 is illustrated using some terminology and functionality of a New Generation (NG) radio access network, as described further herein the virtualized radio access network 24 differs from the radio access network of Fig. 1, for example, in being a packetized virtual radio access network, PVRAN.
  • NG New Generation
  • the fact that the core network 22 and virtualized radio access network 24 are described somewhat in 5G terms does not limit the networks to being 5G networks, as the structure and operation of virtualized radio access network 24 as described herein have applicability to other networks as well.
  • the 5G core network 22 when the core network 22 is a 5G core network, the 5G core network 22 performs various core network functions, such as an access and mobility management function (AMF); session management function; user plane function (UPF); policy control function (PCF); authentication server function (AUSF); unified data management (UDM) function; application function (AP); network exposure function (NEF); NF repository function (FRF); and network slice selection function (NSSF).
  • AMF access and mobility management function
  • UPF user plane function
  • PCF policy control function
  • AUSF authentication server function
  • UDM unified data management
  • AP application function
  • NEF network exposure function
  • FRF NF repository function
  • NSSF network slice selection function
  • the core network 22 also comprises one or more interfaces to access and mobility management function (AMF) 28, e.g., RAN interface(s) 29.
  • the virtualized radio access network 24 serves one or more wireless terminals 30 which communicate over an air or radio interface 31 with virtualized radio access network 24, only one such wireless terminal 30 being shown in Fig. 5 for sake of simplicity.
  • a wireless terminal 30 may comprise a transceiver 32 and wireless terminal processor circuitry 34 which executes one or more programs or code in an operating system and one or more application programs, which may be stored in non-transient memory 36.
  • the wireless terminal 30 may also include interface(s) 38, such as user interfaces.
  • the radio access network 24 comprises plural radio access network nodes.
  • the radio access network nodes comprising radio access network 24 may bear any suitable moniker or label, such as Node B (“NB”), an enhanced Node B (“eNB”), a home eNB (“HeNB”), a gNB (for a New Radio [“NR”] technology system), or some other similar terminology.
  • NB Node B
  • eNB enhanced Node B
  • HeNB home eNB
  • gNB for a New Radio [“NR”] technology system
  • each radio access network node comprises a radio access network node central unit and a radio access network distributed unit.
  • virtualized radio access network 24 as comprising a first radio access network node which in turn comprises radio access node network central unit 40-1 and radio access network node distributed unit 42-1, as well as an n th radio access network node which in turn comprises radio access node network central unit 40-n and radio access network node distributed unit 42-n.
  • n is an integer greater than 1.
  • the central units 40-1 and 40-n of the two radio access network nodes shown in Fig. 5 may also be referred to as CU-1 and CU-n, respectively.
  • the distributed units 42-1 and 42-n of the two radio access network nodes shown in Fig. 5 may also be referred to as DU-1 and DU-n, respectively.
  • both radio access node network central unit 40-1 and radio access network node distributed unit 42-1 may be referred to as belonging to “source” nodes, e.g., as radio access network source node central unit 40-1 and radio access network source node distributed unit 42-1.
  • radio access node network central unit 40-n and radio access network node distributed unit 42-n may be referred to as belonging to “target” nodes, e.g., as radio access network target node central unit 40-n and radio access network source target node distributed unit 42-n.
  • the radio access network node distributed units 42 of each radio access network node may comprise one or more radio access network node distributed unit sites. That is, the radio access network node distributed unit 42 may be geographically or otherwise distributed to one or more locations or manifestations. For example, Fig. 7 shows how radio access network node distributed unit 42-1 may be distributed to plural sites 42-1 1 , 42-1 2 , and 42-1 3 . As used herein, “radio access network node distributed unit” may collectively refer one or more plural sites of radio access network node distributed unit, or to any one site of the radio access network node distributed unit 42.
  • Fig. 7 also shows how protocols handled by the virtualized radio access network 24 are split into high layer protocols and low layer protocols, and does so in contrast to the conventional 5G gNodeB protocol stack.
  • a portion of Fig. 7 to the left of the developmental progression arrow shows that the conventional 5G unified gNodeB handles a protocol stack comprising, from lowest to highest protocol layer: physical layer (PHY) and medium access control (MAC) protocols; radio link control (RLC) protocol; Radio Packet Data Convergence (PDCP) protocol; and Service Data Adaptation Protocol (SDAP) protocol.
  • PHY physical layer
  • MAC medium access control
  • RLC radio link control
  • PDCP Radio Packet Data Convergence
  • SDAP Service Data Adaptation Protocol
  • FIG. 7 to the right of the developmental progression arrow shows the virtualized radio access network 24 of the technology disclosed herein, featuring the radio access node network central unit 40, also known as the anchor CU, and three distributed processor circuitry sites 42 1 , 42 2 , and 42 3 . Although three sites 42 are shown, the split of the protocols of Fig. 7 applies to any number of sites, e.g., one or more sites.
  • Fig. 5 further shows that radio access network node distributed unit 42-1 is connected to radio access node network central unit 40-1 over first packet data domain 46-1; and that radio access network node distributed unit 42-n is connected to radio access node network central unit 40-n over a second or n th packet data domain 46-n.
  • packet data domain means any packet switched domain, such as an Internet Protocol (IP) Virtual Network.
  • IP Internet Protocol
  • the data packet domain 46 may comprise, for example, an Internet Protocol (IP) packet network, although other types of packet networks are also possible.
  • IP Internet Protocol
  • the radio access node network central unit 40 may be connected through its respective packet data domain 46 by pipes or channels 48 to one or more sites comprising the radio access network node distributed unit(s) 42 associated with the respective node. Although only one such pipe 48 is shown in Fig. 5, it will be understood that the radio access node network central unit 40 may be connected by respective plural pipes 48 to plural radio access network node distributed unit sites.
  • a radio access node network central unit 40-x is configured to provide a first tunnel endpoint identifier, CU-x TEID , for a tunnel through which the connection is carried over packet network 46-x to the radio access network node distributed unit 42-x, and the radio access network node distributed unit 42-x is configured to provide a second endpoint identifier, DU-x TEID, for the tunnel.
  • the second endpoint for the tunnel 60 at the distributed processor circuitry 42-x may depend on the particular distributed processor circuitry site to which the tunnel 60 is connected.
  • the suffix “x” is an integer.
  • Each radio access node network central unit 40 comprises various interfaces and node central unit processing circuitry 50.
  • processing circuitry includes memory, e.g., memory circuitry, for storing coded instructions executed by the processing circuitry including an operating system and application programs, as well as any information maintained for operation of a node such as context information, or “context”.
  • the node central unit processing circuitry 50 may also be referred to as “anchor processor circuitry”.
  • the various interfaces comprising each radio access node network central unit 40 may include core network interface 52, e.g., core I/F 52; packet network interface 54; and inter-node or Xn interface 56.
  • Each of the interfaces may comprise circuitry for formatting signals and/or data for transmission/reception with respect to the network and/or units connected thereto, and/or adjusting signal levels or values for such transmission/reception.
  • a radio access network central “unit” means the node central unit processing circuitry 50 which performs functions of the radio access node network central unit 40 as described herein, as well as one or more interfaces which connect radio access node network central unit 40 to other members (e.g., nodes or units) of the radio access network or to the core network 22.
  • Each radio access network node distributed unit 42 comprises various interfaces and node distributed unit processing circuitry 60.
  • the node distributed unit processing circuitry 60 may also be referred to as “distributed circuitry”.
  • the various interfaces comprising each node distributed unit processing circuitry 60 may include mobile termination unit or transceiver 62; packet network interface 64; and inter-node interface 66.
  • Each of the interfaces may comprise circuitry for formatting signals and/or data for transmission/reception with respect to the network and/or units connected thereto, and/or adjusting signal levels or values for such transmission/reception.
  • a radio access network distributed “unit” means the node distributed unit processing circuitry 60 which performs functions of the radio access network node distributed unit 42 as described herein, as well as one or more interfaces which connect radio access network node distributed unit 42 to other members (e.g., nodes or units) of the radio access network or to the wireless terminal(s) served thereby.
  • the elements of virtualized radio access network 24 as described above may also be known by other names.
  • the radio access node network central unit 40 may be referred to as an “anchor central unit”, or “anchor CU”, for example.
  • the radio access network node distributed unit 42 since it may comprise the transceiver circuitry 44, may be referred to as a “radio/DU” or “radio/distributed unit”.
  • the transceiver circuitry 44 may be referred to as a “radio part”, or “radio head”, for example.
  • the transceiver 62 of radio access network node distributed unit 42 may comprise both transmitter circuitry and receiver circuitry, and typically includes antenna(e).
  • the transceiver 62 may include, e.g., amplifier(s), modulation circuitry and other conventional transmission equipment.
  • the transceiver 62 may comprise, e.g., amplifiers, demodulation circuitry, and other conventional receiver equipment.
  • the radio access node network central unit 40 is configured to perform high layer radio access network node operations for a connection with a wireless terminal.
  • Fig. 5 shows node central unit processing circuitry 50 as executing certain high layer protocols, such as Service Data Adaptation Protocol (SDAP) 70 and Packet Data Convergence Protocol (PDCP) 72.
  • SDAP Service Data Adaptation Protocol
  • PDCP Packet Data Convergence Protocol
  • the radio access network node distributed unit 42 is configured to perform low layer radio access network node operations for the connection with the wireless terminal.
  • Fig. 5 accordingly shows node distributed unit processing circuitry 60 as executing lower layer protocols, such as Radio Link Control (RLC) protocol 74 and Physical and Medium Access Control (MAC) protocols 76.
  • RLC Radio Link Control
  • MAC Medium Access Control
  • Layer 1 is the lowest layer and implements various physical layer signal processing functions.
  • Layer 2 is above the physical layer and responsible for the link between the UE and/or gNodeB over the physical layer.
  • the L2 layer may include a media access control (MAC) sublayer, a radio link control (RLC) sublayer, and a packet data convergence protocol (PDCP) sublayer, which are terminated at the gNodeB on the network side.
  • MAC media access control
  • RLC radio link control
  • PDCP packet data convergence protocol
  • the UE may have several upper layers above the L2 layer including a network layer (e.g., IP layer) that is terminated at the PDN gateway on the network side, and an application layer that is terminated at the other end of the connection (e.g., far end UE, server, etc.).
  • the control plane also includes a radio resource control (RRC) sublayer in Layer 3 (L3 layer).
  • RRC sublayer is responsible for obtaining radio resources (i.e., radio bearers) and for configuring the lower layers using RRC signaling.
  • a “context”, sometimes referred to as a “UE context”, is generated and maintained.
  • “context” or “UE context” may include items of information such as an identification of the wireless terminal involved in the connection; encryption keys for the wireless terminal; parameters associated with each of the protocol layers; and other information (such as whether the wireless terminal is moving, measurement activity by the wireless terminal, etc.).
  • the context for a UE connection may be spread throughout a system, e.g., to different elements which support or are involved in the UE connection. For example, for a given UE context there may be contexts in an IMS application server, Core network elements, and various RAN elements, for example.
  • the UE connection may be viewed as having plural “contexts”, e.g., a different portion of the overall UE context perhaps being stored at variously throughout the system.
  • the contexts are generated when the UE powers up and performs registration (e.g., attach procedures). These contexts may have variations in terms of attributes and IE depending on the functionality of the node.
  • the contexts may be stored, maintained, and used by radio resource management (RRM) functionality, which may comprise or be included in Controlling Software or the Operation System.
  • RRM radio resource management
  • the radio resource management (RRM) functionality is split between radio access node network central unit 40 and radio access network node distributed unit 42.
  • node central unit processing circuitries 50-1 and 50-n may each comprise an anchor radio resource management (RRM) controller 80 and node distributed unit processing circuitries 60-1 and 60-n may each comprise a distributed radio resource management (RRM) controller 82.
  • the node distributed unit processing circuitry 60 includes at least some of the radio resource management (RRM) functionality.
  • the anchor radio resource management (RRM) controller manages and stores certain context content in context memory of radio access node network central unit 40; the distributed radio resource management (RRM) controller manages and stores certain context content in the context memory of radio access network node distributed unit 42.
  • the context stored in the context memory of node distributed unit processing circuitry 60 of radio access network node distributed unit 42 includes information pertaining to admission control, including resource allocation and tracking for all UEs within the coverage area of the particular distributed processor circuitry site.
  • the UE context stored in the context memory of radio access network node distributed unit 42 may be referred to as the “distributed unit version of the UE context”.
  • the context stored in the context memory of the node central unit processing circuitry 50 includes information pertaining to IP connectivity contexts, Identifications, TEIDs, security keys, and mobility-related contexts, and may be referred to as the “central unit version of the UE context”.
  • the low layer radio access network node operations comprise a medium access control (MAC) operation.
  • the medium access control (MAC) operation nay be executed by a MAC controller 84 or MAC entity which may comprise or be included in node distributed unit processing circuitry 60.
  • the MAC controller 84 may handle at least some of the radio resource management (RRM) functionality required for a connection between the wireless terminal and the radio access network.
  • RRM radio resource management
  • all RRC messages may be terminated at the MAC layer, and hence become MAC Control Functions.
  • a MAC controller 84 of node distributed unit processing circuitry 60 is configured to handle the data radio bearers, DRBs, and signaling radio bearers, SRBs, for the connection.
  • the MAC controller 64 allocates, modifies, and releases all data radio bearers, DRBs, and signaling radio bearers, SRBs, for the connection.
  • some or all security/encryption functions may or may not (for support of backward compatibility UEs and operations) be moved from the Radio Packet Data Convergence (PDCP) layer to the MAC layer, e.g., some keys are negotiated by a MAC controller of node distributed unit processing circuitry 60.
  • PDCP Radio Packet Data Convergence
  • Performing the security functions at the MAC layer allows for faster key exchanges and session establishment and release, hence enhancing the network performance and mobility.
  • keeping the same context (at the CU or the PDCP) after handover from one distributed processor circuitry site to another means that the same encryption keys may be utilized before, during, and after the handover as before the handover process is initiated, which eliminates the need for the establishment/release or the reconfiguration of the PDCP entity including further security negotiations, and thus conserves processing resources and expedites the handover.
  • keeping a “same context” in a handover operation means at least one and preferably both of the following: (1) that the context maintained by anchor radio resource management (RRM) controller 58 for the anchor processor circuitry 40 remains mostly the same (especially the encryption functionality and Key assignments for CP and UP traffic is maintained in the CU/PDCP) after the handover as before the handover.
  • RRM radio resource management
  • the context information at the Anchor CU unit including the context information related to the new connections established with the New/target DU) as used by the radio access node network central unit 40 for the involved connection after the handover; and (2) that the PDCP/CU related context information as used by the radio access network node distributed unit 42 for the connection involving the wireless terminal does not change when the wireless terminal is handed over from one distributed processor circuitry site to another distributed processor circuitry site.
  • the context at the CU may be updated to include information related to the new distributed processor circuitry site, but the contexts related to the UE and the CP/UP traffic, e.g., Keys, PDCP entities, ...etc., at the PDCP, should not be affected since everything is anchored at that radio access node network central unit 40, e.g., at the CU. Only the DU-related contexts such as DU-TEIDs, CU-DU connection information, etc., are expected to change and hence it shall be updated at the radio access node network central unit 40 and established at the distributed processor circuitry site.
  • DU-related contexts such as DU-TEIDs, CU-DU connection information, etc.
  • At least control plane connectivity of the wireless terminal is changed from to radio access network node central unit 40-1 to radio access node network central unit 40-n.
  • Such change of connectivity is represented by arrow 90 in Fig. 5, which generally shows wireless terminal 30 moving from a cell served by radio access network node distributed unit 42-1 to a “primed” position depicted by wireless terminal 30’ wherein the wireless terminal is better served by a cell of radio access network node distributed unit 42-n.
  • the change of connectivity results also in a change of utilized IP virtual network, from packet network 46-1 to packet network 46-2, for the control plane signals, and when applicable, the user plane data.
  • the change in connectivity of the wireless terminal 30 is a handover of an active connection involving the wireless terminal 30, and as such involves a change of both control plane connectivity and user plane connectivity.
  • Fig. 10 - Fig. 13, discussed hereinafter, show various example scenarios of a handover type of change of connectivity.
  • the scenarios of Fig. 10 - Fig. 13 differ in accordance with, e.g., the entity which forms the basis/base of the change of connectivity, e.g., the unit which essentially controls or coordinates the change of connectivity.
  • the wireless terminal 30 is in idle mode so that the change of connectivity is a cell reselection involving only a change of control plane connectivity.
  • the wireless terminal 30 and network nodes/elements shown in Fig. 5 may have functionality herein known as a connectivity controller, e.g., in the form of circuitry, to handle respective participation of the terminal, node, or element in the connectivity change of the wireless terminal.
  • the wireless terminal 30 may include terminal connectivity controller 92 which governs actions of wireless terminal 30 in a change of connectivity situation.
  • the terminal connectivity controller 92 may be subsumed in or comprise terminal processor circuitry 34, but is shown distinctly in view of pertinence of the connectivity change functionality of processor circuitry 34 to the topics described herein.
  • each of radio access network node distributed units 42-1 and 42-n may comprise distributed unit connectivity controller 94, which for each unit in turn may be included in node distributed unit processing circuitry 60.
  • each of radio access network node central unit 40-1 and radio access node network central unit 40-n may comprise central unit connectivity controller 96, which for each unit in turn may be included in node central unit processing circuitry 50.
  • the terminal connectivity controller 92, distributed unit connectivity controller 94, and central unit connectivity controller 96 sequence participation of the respective entity, e.g., wireless terminal, central unit, or distributed unit, in the overall connectivity change.
  • the operations or acts of the various connectivity controllers for each unit may vary for each of the scenarios of Fig. 10 - Fig.
  • the change in connectivity from one radio access network node distributed unit to another radio access network node distributed unit involves operation of a connectivity controller, e.g., of processor circuitry.
  • the change of connectivity may involve operation of processor circuitry in the form of connectivity controllers at several entities, such as wireless terminal 30, the radio access network node distributed units, and the radio access network node central units.
  • the change of connectivity may be “based” upon one of the entities of the radio access network - either the wireless terminal, a radio access network node distributed unit, or a radio access network node central unit, in which case the connectivity controller for that unit may become, and herein is known, as the base or “controlling” connectivity controller.
  • the base or “controlling” connectivity controller may be the central unit connectivity controller 96 of radio access network node central unit 40-1; in the scenario of Fig. 11, the base or “controlling” connectivity controller may be the terminal connectivity controller 92 of wireless terminal 30; in the scenario of Fig. 12 and the scenario of Fig.
  • the base or “controlling” connectivity controller may be the distributed unit connectivity controller 94 of radio access network node distributed unit 42-1.
  • the scenario of Fig. 14 involves cell re-selection and thus the terminal connectivity controller 92 may be the base or “controlling” connectivity controller.
  • a “base” connectivity controller 92 supervises or sequences the overall operations of a change of connectivity procedure.
  • Fig. 9 shows example, representative, basic acts or steps comprising a method of operating the radio access network of Fig. 5.
  • Act 9-1 comprises making a determination that a wireless terminal should be handed over from radio access network source node distributed unit to radio access network target node distributed unit.
  • the radio access network source node distributed unit is connected to radio access network source node central unit over a first packet data domain
  • the radio access network target node distributed unit is connected to radio access network target node central unit over a second packet data domain.
  • Act 9-2 comprises, in accordance with the determination, changing at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit and thereby routing control plane signaling for the wireless terminal through the second packet data domain.
  • Fig. 10- Fig. 14 show various example scenarios of change of connectivity.
  • Each of Fig. 11 - Fig. 14, shows telecommunications system 20 as comprising the aforementioned radio access network node central unit 40-1, radio access network node distributed unit 42-1, radio access node network central unit 40-n, radio access network node distributed unit 42-n, and wireless terminal 30.
  • Arrows or lines in each of Fig. 11 - Fig. 14 that are dashed and single dotted depict both user plane connectivity and control plane connectivity, whether or not so labeled; arrow or lines in each of Fig. 11 - Fig. 14 that are dashed and double dotted depict only control plane connectivity (no user plane connectivity), whether or not so labeled.
  • FIG. 11 - Fig. 12 that are completely dotted representing temporary tunneling operations between source node central units, e.g., establishing or updating a tunnel, such as a tunnel between radio access network node central unit 40-1 and radio access node network central unit 40-n, for example.
  • Fig. 10 shows an inter-control unit connected mode handover procedure which is based on a radio access network node central unit for the radio access network of Fig. 5.
  • Act 10-1 depicts the fact that wireless terminal 30, in a position shown at the bottom left of Fig. 5, is in connected mode.
  • the wireless terminal 30 is also known as UE-1. Since wireless terminal 30 is in connected mode, respective versions of UE contexts for wireless terminal 30 exists at each of radio access network node distributed unit 42-1 and radio access network node central unit 40-1, since at the beginning of the scenario wireless terminal 30 is served by the source node.
  • Act 10-2 shows the distributed unit version of the UE context for wireless terminal 30 as existing at radio access network node distributed unit 42-1; act 10-3 shows the central unit version of the UE context for wireless terminal 30 as existing at radio access network node central unit 40-1. Act 10-3 further shows that the radio access network node central unit 40-1 also knows the endpoints for the tunnel through packet network 46-1 for the connection involving wireless terminal 30.
  • Fig. 10 further shows: as act 10-4, that both user plane connectivity and control plane connectivity exists between wireless terminal 30 and radio access network node distributed unit 42-1; as act 10-5, that both user plane connectivity and control plane connectivity exists between radio access network node distributed unit 42-1 and radio access network node central unit 40-1; and, as act 10-6, that both user plane connectivity and control plane connectivity exists between radio access network node central unit 40-1 and core network 22.
  • the wireless terminal 30 While in connected mode, the wireless terminal 30 makes certain measurements of signals received from plural radio access network nodes, such as signals from radio access network node distributed unit 42-1 and radio access network node distributed unit 42-n, as shown by act 10-7. As act 10-8, the wireless terminal 30 sends, either periodically or upon request, measurement reports to radio access network source node central unit 40-1.
  • plural radio access network nodes such as signals from radio access network node distributed unit 42-1 and radio access network node distributed unit 42-n, as shown by act 10-7.
  • act 10-8 the wireless terminal 30 sends, either periodically or upon request, measurement reports to radio access network source node central unit 40-1.
  • Fig. 10 shows a central unit-based change of connectivity scenario.
  • act 10-9 shows radio access network node central unit 40-1 making a determination that a wireless terminal should be handed over from a source radio access network source node distributed unit to a target radio access network target node distributed unit (e.g., executing act 9-1 of Fig. 9).
  • Such determination may occur, for example, when the wireless terminal 30 moves according to change of connectivity arrow 90 to the primed position 30’ in Fig. 5.
  • the wireless terminal 30 has been served by the source node, e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the determination of act 10-9 may be made on the basis of signal measurements made by wireless terminal 30, from which the terminal connectivity controller 92, for example, may make a determination that wireless terminal 30 would be better served by a target node, e.g., radio access network node distributed unit 42-n and radio access node network central unit 40-n, rather than the source node.
  • the determination of act 10-9 may be made by central unit connectivity controller 96 of radio access network node central unit 40-1.
  • the radio access network node central unit 40-1 not only determines that a handover should be made, but also ascertains (from the measurement report sent by wireless terminal 30) the identity of the radio access network target node distributed unit, which in the illustration scenario is radio access network node distributed unit 42-n.
  • the radio access network node central unit 40-1 also determines the target central unit associated with the target distributed unit, which in the illustrated scenario is radio access node network central unit 40-n.
  • the target central unit utilizes a different packet network 46, e.g., packet network 46-n rather than packet network 46-1.
  • the radio access network node central unit 40-1 If the radio access network node central unit 40-1 makes a determination that the wireless terminal 30 would be better served by the target node, as act 10-10 the radio access network node central unit 40-1 sends a handover request to radio access node network central unit 40-n.
  • the handover request of act 10-10 may be sent over the X n interface from radio access network node central unit 40-1 to radio access node network central unit 40-n.
  • the target radio access node network central unit 40-n Upon receiving the handover request of act 10-10, as act 10-11 the target radio access node network central unit 40-n exchanges information with its radio access network node distributed unit 42-n.
  • the radio access network node distributed unit 42-n establishes a UE context, e.g., the distributed unit version of the UE-1 context for wireless terminal 30, and creates a tunnel endpoint identifier at radio access network node distributed unit 42-n for a tunnel, e.g., the tunnel that will be between radio access network node distributed unit 42-n and radio access node network central unit 40-n.
  • a tunnel endpoint identifier TEID for radio access network node distributed unit 42-n is shown in Fig.
  • the radio access network node distributed unit 42-n receives, from radio access node network central unit 40-n, information used to establish the distributed unit version of the UE-1 context.
  • Act 10-13 shows radio access node network central unit 40-n as creating a central unit version of the UE context for wireless terminal 30, as well as establishing a tunnel endpoint identifier TEID at itself, e.g., CU-n TEID, and storing certain encryption keys, e.g., KEYS: UE-1, which were received in the handover request of act 10-10 from the radio access network node central unit 40-1 for use in encryption/decryption of communications with wireless terminal 30.
  • KEYS e.g., KEYS: UE-1
  • the radio access node network central unit 40-n After both radio access node network central unit 40-n and radio access network node distributed unit 42-n have prepared themselves for the handover in the manner of act 10-12 and act 10-13, the radio access node network central unit 40-n sends a handover response message to radio access network node central unit 40-1 as shown by act 10-14.
  • the radio access node network central unit 40-n supplies radio access network node central unit 40-1 with the endpoints for the tunnel which will connect radio access node network central unit 40-n and radio access network node distributed unit 42-n for the handed-over connection of wireless terminal 30, e.g., DU-N TEID and CU-N TEID.
  • the handover response message of act 10-14 will include KEYS.
  • the radio access network node central unit 40-1 Upon being informed that the target node is prepare for the handover, as act 10-15 the radio access network node central unit 40-1 sends a handover command to radio access network node distributed unit 42-1, which in turn as act 10-16 sends a handover command to wireless terminal 30.
  • the handover command of act 10-16 includes an identification of the radio access network target node distributed unit, i.e., radio access network node distributed unit 42-n; the tunnel endpoint identifiers for use after the handover, e.g., DU-N TEID and CU-N TEID, and the KEYS.
  • wireless terminal 30 Upon receipt of the handover command, as act 10-17 wireless terminal 30 essentially executes a handover procedure which involves, e.g., selecting the target distributed unit. Thereafter, as depicted by act 10-18, the wireless terminal 30 performs a random access procedure with the radio access network target node distributed unit 42-n. Assuming that the random access procedure is successful, as act 10-19 the UE-1 context is updated.
  • the radio access node network central unit 40-n After sending its handover response message of act 10-14, as act 10-20 the radio access node network central unit 40-n establishes a context for the wireless terminal 30, e.g., context UE-1, and creates a tunnel endpoint identifier CU-TEID.
  • the dotted line of act 10-21 represents establishment of a temporary tunnel between the target radio access node network central unit 40-n and the source radio access network node central unit 40-1, through which the radio access node network central unit 40-n retrieves the UE-1 context for wireless terminal 30.
  • both user plane connectivity and control plane connectivity is established between radio access network node central unit 40-1 and radio access node network central unit 40-n, as depicted by act 10-22. Both user plane connectivity and control plane connectivity are established between radio access node network central unit 40-n and radio access network node distributed unit 42-n, as shown by act 10-23. Thereafter, as act 10-24, core network tunneling is updated between radio access node network central unit 40-n and core network 22. The core network tunnel update of act 10-24 assures that there can be path of connectivity between radio access node network central unit 40-n and core network 22 after the handover.
  • one or more signaling radio bearer(s) and data radio bearer(s) between wireless terminal 30 and radio access network node distributed unit 42-n are updated using a MAC procedures.
  • establishment and modification of signaling radio bearer(s) and data radio bearer(s) may be accomplished using MAC procedures, e.g., MAC controller 84.
  • both user plane connectivity and distributed processor circuitry exists between wireless terminal 30 and radio access network node distributed unit 42-n, as reflected by act 10-26; between radio access network node distributed unit 42-n and radio access node network central unit 40-n, as reflect by act 10-27; and between radio access node network central unit 40-n and core network 22, as reflected by act 10-28.
  • the wireless terminal 30 is (again) in connected mode, as shown by act 10-29.
  • the temporary tunnel between radio access network node central unit 40-1 and radio access node network central unit 40-n is released as act 10-30. Confirmation of release of the temporary tunnel between radio access network node central unit 40-1 and radio access node network central unit 40-n may be sent to radio access network node distributed unit 42-1 as act 10-31.
  • the wireless terminal 30 and radio access network node distributed unit 42-n may engage in various MAC-based operations generally grouped as at 11-32, including but not limited to: act 10-33: releasing or reconfiguring one or more data radio bearer(s) and/or signaling radio bearer(s); act 10-34: re-establishing one or more data radio bearer(s) and/or signaling radio bearer(s), as may occur for conventional connections, but being MAC-based, e.g., MAC-controlled, in the example embodiment and mode.
  • Fig. 11 shows an inter-control unit connected mode handover procedure which is based on a wireless terminal for the radio access network of Fig. 5.
  • Act 11-1 depicts the fact that wireless terminal 30, in a position shown at the bottom left of Fig. 5, is in connected mode.
  • the wireless terminal 30 is also known as UE-1. Since wireless terminal 30 is in connected mode, Respective versions of UE contexts for wireless terminal 30 exists at each of radio access network node distributed unit 42-1 and radio access network node central unit 40-1, since at the beginning of the scenario wireless terminal 30 is served by the source node.
  • Act 11-2 shows the distributed unit version of the UE context for wireless terminal 30 as existing at radio access network node distributed unit 42-1; act 11-3 shows the central unit version of the UE context for wireless terminal 30 as existing at radio access network node central unit 40-1. Act 11-3 further shows that the radio access network node central unit 40-1 also knows the endpoints for the tunnel through packet network 46-1 for the con.
  • Fig. 11 further shows: as act 11-4, that both user plane connectivity and control plane connectivity exists between wireless terminal 30 and radio access network node distributed unit 42-1; as act 11-5, that both user plane connectivity and control plane connectivity exists between radio access network node distributed unit 42-1 and radio access network node central unit 40-1; and, as act 11-6, that both user plane connectivity and control plane connectivity exists between radio access network node central unit 40-1 and core network 22.
  • the wireless terminal 30 While in connected mode, the wireless terminal 30 makes certain measurements of signals received from plural radio access network nodes, such as signals from radio access network node distributed unit 42-1 and radio access network node distributed unit 42-n.
  • the wireless terminal 30 is entrusted to make a determination that it should be handed over from a source radio access network source node distributed unit to a target radio access network target node distributed unit (e.g., executing act 9-1 of Fig. 9). Such determination may occur, for example, when the wireless terminal 30 moves according to change of connectivity arrow 90 to the primed position 30’ in Fig. 5.
  • the wireless terminal 30 Before the movement depicted by change of connectivity arrow 90 the wireless terminal 30 has been served by the source node, e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the determination of act 11-7 may be made on the basis of signal measurements made by wireless terminal 30, from which the terminal connectivity controller 92, for example, may make a determination that wireless terminal 30 would be better served by a target node, e.g., radio access network node distributed unit 42-n and radio access node network central unit 40-n, rather than the source node.
  • the wireless terminal 30 not only determines that a handover should be made, but also ascertains (based on its measurements) the identity of the radio access network target node distributed unit, which in the illustration scenario is radio access network node distributed unit 42-n. Knowing also the topology of the radio access network, the wireless terminal 30 may also determine the target central unit associated with the target distributed unit, which in the illustrated scenario is radio access node network central unit 40-n.
  • the target central unit utilizes a different packet network 46, e.g., packet network 46-n rather than packet network 46-1.
  • the wireless terminal 30 If the wireless terminal 30 indeed makes a determination that the wireless terminal 30 would be better served by the target node, as act 11-8 the wireless terminal 30 sends a handover request to source radio access network node central unit 40-1.
  • the handover request of act 11-8 may be sent over the air or radio interface from wireless terminal 30 to radio access network node central unit 40-1.
  • the handover request of act 11-8 includes an identification of the target node, of radio access network target node distributed unit 42-n.
  • the radio access network node distributed unit 42-1 Upon receiving the handover request of act 11-8, as act 11-9 the radio access network node distributed unit 42-1 essentially relays the handover request to radio access network node central unit 40-1.
  • the radio access network node central unit 40-1 Upon receipt of the handover request which identifies the radio access network target node distributed unit 42-n, as act 11-10 the radio access network node central unit 40-1, knowing the topology of the radio access network and thus what central units serve various distributed unit, determines the central unit (e.g., radio access node network central unit 40-n) that is associated with radio access network node distributed unit 42-n.
  • the radio access network node central unit 40-1 then as act 11-11 sends the handover request to the target radio access node network central unit 40-n.
  • the radio access network node central unit 40-1 includes or otherwise provides the radio access node network central unit 40-n with information such as the identifies of the wireless terminal involved in the handover, as well as the identifies of the source node entities (e.g., radio access network node central unit 40-1 and radio access network node distributed unit 42-1) which have thus far served wireless terminal 30 as well as tunnel endpoints thus far utilized for wireless terminal 30, including DU-1 TEID and CU-1 TEID, as well as KEYs utilized for encryption/decryption.
  • the source node entities e.g., radio access network node central unit 40-1 and radio access network node distributed unit 42-1
  • the radio access node network central unit 40-n Upon receipt of the handover request of act 11-11, as act 11-12 the radio access node network central unit 40-n uses the information received in the handover request to establish a distributed unit version of the context, and also establishes a tunnel endpoint through which radio access node network central unit 40-n will communicate for wireless terminal 30 (e.g., CU-2 TEID), and to established KEYs for UE-1.
  • wireless terminal 30 e.g., CU-2 TEID
  • the radio access node network central unit 40-n After beginning to prepare itself for handover, as act 11-13 the radio access node network central unit 40-n sends a handover prepare message to radio access network node distributed unit 42-n. As act 11-14 the radio access network node distributed unit 42-n uses the information received in the handover prepare message of act 11-13 to establish at radio network node distributed unit 42-n its distributed unit version of the UE context for wireless terminal 30, e.g., UE-1 context, and also creates an tunnel endpoint for communicating over packet network 46-n with radio access node network central unit 40-n for wireless terminal 30, and obtains the identifier for such endpoint, e.g., DU-N TEID.
  • UE context for wireless terminal 30 e.g., UE-1 context
  • the handover response command of act 11-15 includes information which the wireless terminal 30 may need for implementing the handover, e.g., the tunnel endpoints DU-N TEID and CU-N TEID, KEYs, and DRBs.
  • the radio access network node central unit 40-1 sends a handover command to radio access network node distributed unit 42-1, which in turn as act 11-17 sends a handover command to wireless terminal 30.
  • the handover command of act 11-17 includes an identification of the radio access network target node distributed unit, i.e., radio access network node distributed unit 42-n; the tunnel endpoint identifiers for use after the handover, e.g., DU-N TEID and CU-N TEID, and the KEYS.
  • wireless terminal 30 Upon receipt of the handover command, as act 11-18 wireless terminal 30 essentially executes a handover procedure which involves, e.g., selecting the target distributed unit. Thereafter, as depicted by act 11-19, the wireless terminal 30 performs a random access procedure with the radio access network target node distributed unit 42-n. Thereafter, assuming that the random access procedure is successful, as act 11-20 the UE-1 context is updated.
  • the radio access node network central unit 40-n After sending its handover response message of act 11-15, as act 11-21 the radio access node network central unit 40-n establishes a context for the wireless terminal 30, e.g., context UE-1, and creates a tunnel endpoint identifier CU-TEID.
  • the dotted line of act 11-22 represents establishment of a temporary tunnel between the target radio access node network central unit 40-n and the source radio access network node central unit 40-1, through which the radio access node network central unit 40-n retrieves the UE-1 context for wireless terminal 30.
  • both user plane connectivity and control plane connectivity is established between radio access network node central unit 40-1 and radio access node network central unit 40-n, as depicted by act 11-23.
  • Both user plane connectivity and control plane connectivity is established between radio access node network central unit 40-n and radio access network node distributed unit 42-n, as shown by act 11-24.
  • core network tunneling is updated between radio access node network central unit 40-n and core network 22.
  • one or more signaling radio bearer(s) and data radio bearer(s) between wireless terminal 30 and radio access network node distributed unit 42-n are updated using a MAC procedures.
  • MAC procedures e.g., MAC controller 84.
  • both user plane connectivity and distributed processor circuitry exists between wireless terminal 30 and radio access network node distributed unit 42-n, as reflected by act 11-27; between radio access network node distributed unit 42-n and radio access node network central unit 40-n, as reflected by act 11-28; and between radio access node network central unit 40-n and core network 22, as reflected by act 11-29.
  • the wireless terminal 30 is (again) in connected mode, as shown by act 11-30.
  • the temporary tunnel between radio access network node central unit 40-1 and radio access node network central unit 40-n is released as act 11-31. Confirmation of release of the temporary tunnel between radio access network node central unit 40-1 and radio access node network central unit 40-n may be sent to radio access network node distributed unit 42-1 as act 11-32.
  • the wireless terminal 30 and radio access network node distributed unit 42-n may engage in various MAC-based operations generally grouped as at 11-33, including but not limited to: act 11-34: releasing or reconfiguring one or more data radio bearer(s) and/or signaling radio bearer(s); act 11-35: re-establishing one or more data radio bearer(s) and/or signaling radio bearer(s), as may occur for conventional connections, but being MAC-based, e.g., MAC-controlled, in the example embodiment and mode.
  • Fig. 12 is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig. 5, in which the handover procedure is based on a radio access network node distributed unit, but wherein the determination to make the handover is performed by the wireless terminal 30.
  • Act 12-1 depicts the fact that wireless terminal 30, in the unprimed position shown at the bottom left of Fig. 5, is in connected mode.
  • the wireless terminal 30 is also known as UE-1. Since wireless terminal 30 is in connected mode, Respective versions of UE contexts for wireless terminal 30 exists at each of radio access network node distributed unit 42-1 and radio access network node central unit 40-1, since at the beginning of the scenario wireless terminal 30 is served by the source node.
  • Act 12-2 shows the distributed unit version of the UE context for wireless terminal 30 as existing at radio access network node distributed unit 42-1; act 12-3 shows the central unit version of the UE context for wireless terminal 30 as existing at radio access network node central unit 40-1.
  • Act 12-3 further shows that the radio access network node central unit 40-1 also knows the endpoints for the tunnel through packet network 46-1 for the connection involving wireless terminal 30, e.g., the tunnel endpoint identifiers DU-1 TEID and CU-1 TEID.
  • Fig. 12 further shows: as act 12-4, that both user plane connectivity and control plane connectivity exists between wireless terminal 30 and radio access network node distributed unit 42-1; as act 12-5, that both user plane connectivity and control plane connectivity exists between radio access network node distributed unit 42-1 and radio access network node central unit 40-1; and, as act 12-6, that both user plane connectivity and control plane connectivity exists between radio access network node central unit 40-1 and core network 22.
  • the wireless terminal 30 While in connected mode, the wireless terminal 30 makes certain measurements of signals received from plural radio access network nodes, such as signals from radio access network node distributed unit 42-1 and radio access network node distributed unit 42-n.
  • the wireless terminal 30 is entrusted to make a determination that a wireless terminal should be handed over from a source radio access network source node distributed unit to a target radio access network target node distributed unit (e.g., executing act 9-1 of Fig. 9). Such determination may occur, for example, when the wireless terminal 30 moves according to change of connectivity arrow 90 to the primed position 30’ in Fig. 5.
  • the wireless terminal 30 Before the movement depicted by change of connectivity arrow 90 the wireless terminal 30 has been served by the source node, e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the determination of act 12-7 may be made on the basis of signal measurements made by wireless terminal 30, from which the terminal connectivity controller 92, for example, may make a determination that wireless terminal 30 would be better served by a target node, e.g., radio access network node distributed unit 42-n and radio access node network central unit 40-n, rather than the source node.
  • the wireless terminal 30 not only determines that a handover should be made, but also ascertains (based on its measurements) the identity of the radio access network target node distributed unit, which in the illustration scenario is radio access network node distributed unit 42-n. Knowing also the topology of the radio access network, the wireless terminal 30 may also determine the target central unit associated with the target distributed unit, which in the illustrated scenario is radio access node network central unit 40-n.
  • the target central unit utilizes a different packet network 46, e.g., packet network 46-n rather than packet network 46-1.
  • the wireless terminal 30 If the wireless terminal 30 indeed makes a determination that the wireless terminal 30 would be better served by the target node, as act 12-8 the wireless terminal 30 sends a handover request to source radio access network node central unit 40-1.
  • the handover request of act 12-8 may be sent over the air or radio interface from wireless terminal 30 to radio access network node central unit 40-1.
  • the handover request of act 12-8 includes an identification of the target node, of radio access network target node distributed unit 42-n.
  • the radio access network node distributed unit 42-1 Upon receiving the handover request of act 12-8, as act 12-9 the radio access network node distributed unit 42-1 essentially relays the handover request to radio access node network central unit 40-n.
  • the radio access network node distributed unit 42-n uses information included in the handover request of act 12-9 to establish its version of the context for the wireless terminal 30, e.g., UE-1 context, which includes, e.g., the keys used for the connection with wireless terminal 30.
  • the radio access network node distributed unit 42-n establishes a tunnel endpoint for itself, e.g., DU-N TEID, for the tunnel through packet network 46-n that will connect radio access network node distributed unit 42-n to radio access node network central unit 40-n.
  • the radio access network node distributed unit 42-n relays the handover request message to radio access node network central unit 40-n.
  • the handover request message of act 12-11 as received by radio access node network central unit 40-n includes identifiers of the wireless terminal 30, the radio access network source node distributed unit 42-1 and source radio access network node central unit 40-1, the UE-1 context,the tunnel endpoint identifiers, and the KEYS for the connection involving wireless terminal 30.
  • the radio access node network central unit 40-n Upon receiving the handover request message of act 12-11, as act 12-12 the radio access node network central unit 40-n establishes its context for UE-1 using the information forwarded in the handover request message, and establishes its endpoint and endpoint identifier CU-N TEID for the tunnel that connects radio access node network central unit 40-n and radio access network node distributed unit 42-n through packet network 46-n. Then, as act 12-13, the radio access node network central unit 40-n establishes a temporary tunnel with source radio access network node central unit 40-1, through which the UE-1 context is retrieved. Act 12-14 shows that both user plane connectivity and control plane connectivity have been established between radio access node network central unit 40-n and radio access network central unit 40-1. Act 12-15 shows that both user plane connectivity and control plane connectivity have been established between radio access node network central unit 40-n and radio access network node distributed unit 42-n.
  • the radio access node network central unit 40-n updates a tunnel between itself and core network 22. Thereafter, as act 12-17, the radio access node network central unit 40-n sends a handover response message to radio access network node distributed unit 42-n.
  • the handover response message of act 12-17 includes the tunnel endpoint identifier CU-N TEID for radio access node network central unit 40-n and the KEYS.
  • the radio access network node distributed unit 42-n as act 12-18 relays the handover response to radio access network node distributed unit 42-1.
  • the radio access network node central unit 40-1 Upon receipt of the handover response of act 12-18, as act 12-19 the radio access network node central unit 40-1 sends a handover command to wireless terminal 30.
  • the handover command of act 12-15 includes identifiers of the radio access network target node distributed unit 42-n, the tunnel endpoint identifiers DU-N TEID and CU-N TEID for the tunnel through packet network 46-n, the KEYS, and access DRBs.
  • the source radio access network node central unit 40-1 sends a handover complete message to target radio access node network central unit 40-n.
  • wireless terminal 30 Upon receipt of the handover command, as act 12-21 wireless terminal 30 essentially executes a handover procedure which involves, e.g., selecting the target distributed unit. Thereafter, as depicted by act 12-22, the wireless terminal 30 performs a random access procedure with the radio access network target node distributed unit 42-n. Assuming that the random access procedure is successful, as act 12-23 the UE-1 context is updated.
  • act 12-24 shows that user plane connectivity and control plane connectivity exists between radio access node network central unit 40-n and core network 22. Moreover, as act 12-25 the temporary tunnel between source radio access network node central unit 40-1 and target radio access node network central unit 40-n is released. Act 12-26 shows that user plane connectivity and control plane connectivity exists between target radio access node network central unit 40-n and radio access network node distributed unit 42-n.
  • Act 12-27 depicts MAC-based modification of one or more data radio bearer(s) and signaling radio bearer(s) between wireless terminal 30 and radio access network node distributed unit 42-n.
  • establishment, modification, and release of both signaling radio bearer(s) and data radio bearer(s) is preferably performed by the MAC layer in the technology disclosed herein.
  • act 12-28 both user plane connectivity and control plane connectivity exists between wireless terminal 30 and target radio access node network central unit 40-n, as depicted by act 12-28.
  • act 12-29 shows wireless terminal 30 as again being in connected mode.
  • Fig. 13 is a signal flow diagram showing an inter-control unit connected mode handover procedure for the radio access network of Fig. 5 which is based on a radio access network node distributed unit, and wherein the determination to make the handover is performed by the radio access network source node distributed unit.
  • Act 13-1 depicts the fact that wireless terminal 30, in the unprimed position shown at the bottom left of Fig. 5, is in connected mode.
  • the wireless terminal 30 is also known as UE-1. Since wireless terminal 30 is in connected mode, Respective versions of UE contexts for wireless terminal 30 exists at each of radio access network node distributed unit 42-1 and radio access network node central unit 40-1, since at the beginning of the scenario wireless terminal 30 is served by the source node.
  • Act 13-2 shows the distributed unit version of the UE context for wireless terminal 30 as existing at radio access network node distributed unit 42-1; act 13-3 shows the central unit version of the UE context for wireless terminal 30 as existing at radio access network node central unit 40-1. Act 13-3 further shows that the radio access network node central unit 40-1 also knows the endpoints for the tunnel through packet network 46-1 for the connection involving wireless terminal 30, e.g., the tunnel endpoint identifiers DU-1 TEID and CU-1 TEID.
  • Fig. 12 further shows: as act 13-4, that both user plane connectivity and control plane connectivity exists between wireless terminal 30 and radio access network node distributed unit 42-1; as act 13-5, that both user plane connectivity and control plane connectivity exists between radio access network node distributed unit 42-1 and radio access network node central unit 40-1; and, as act 13-6, that both user plane connectivity and control plane connectivity exists between radio access network node central unit 40-1 and core network 22.
  • the wireless terminal 30 While in connected mode, as shown by act 13-7 the wireless terminal 30 makes certain measurements of signals received from plural radio access network nodes, such as signals from radio access network node distributed unit 42-1 and radio access network node distributed unit 42-n. The measurements made by wireless terminal 30 are sent, periodically or otherwise, e.g., upon request, to radio access network source node distributed unit 42-1 in measurement reports depicted by act 13-8.
  • the radio access network source node distributed unit 42-1 is entrusted to make a determination that a wireless terminal should be handed over from a source radio access network source node distributed unit to a target radio access network target node distributed unit (e.g., executing act 9-1 of Fig. 9).
  • Such determination may occur, for example, when the wireless terminal 30 moves according to change of connectivity arrow 90 to the primed position 30’ in Fig. 5. Before the movement depicted by change of connectivity arrow 90 the wireless terminal 30 has been served by the source node, e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the determination of act 13-9 may be made on the basis of signal measurements made by wireless terminal 30, from which the distributed unit connectivity controller 94, for example, may make a determination that wireless terminal 30 would be better served by a target node, e.g., radio access network node distributed unit 42-n and radio access node network central unit 40-n, rather than the source node.
  • the radio access network node distributed unit 42-1 not only determines that a handover should be made, but also ascertains (based on the received measurements) the identity of the radio access network target node distributed unit, which in the illustration scenario is radio access network node distributed unit 42-n. Knowing also the topology of the radio access network, the radio access network node distributed unit 42-1 may also determine the target central unit associated with the target distributed unit, which in the illustrated scenario is radio access node network central unit 40-n.
  • the target central unit utilizes a different packet network 46, e.g., packet network 46-n rather than packet network 46-1.
  • the radio access network node distributed unit 42-1 When the radio access network node distributed unit 42-1 indeed makes a determination that the wireless terminal 30 would be better served by the target node, as act 13-10 the radio access network node distributed unit 42-1 sends a handover request to radio access network target node distributed unit 42-n.
  • the handover request of act 13-10 may be sent over an interface that connects the two distributed units.
  • the radio access network node distributed unit 42-n establishes its context for the wireless terminal 30, UE-1 context, and obtains the KEYS for the connection with wireless terminal 30.
  • the radio access network target node distributed unit 42-n Upon receiving the handover request of act 13-10 and after establishing its context as act 13-11, as act 13-12 the radio access network target node distributed unit 42-n essentially relays the handover request to target radio access node network central unit 40-n.
  • the radio access node network central unit 40-n uses information included in the handover request of act 13-12 to establish its version of the context for the wireless terminal 30, e.g., UE-1 context, which includes, e.g., the KEYS used for the connection with wireless terminal 30.
  • the radio access node network central unit 40-n establishes a tunnel endpoint for itself, e.g., CU-N TEID, for the tunnel through packet network 46-n that will connect radio access network node distributed unit 42-n to radio access node network central unit 40-n.
  • a tunnel endpoint for itself, e.g., CU-N TEID
  • the radio access node network central unit 40-n After establishing its context for wireless terminal 30, as act 13-14 the radio access node network central unit 40-n establishes a temporary tunnel with source radio access network node central unit 40-1, through which the UE-1 context is retrieved. At this point both user plane connectivity and control plane connectivity exist between radio access node network central unit 40-n and radio access network node central unit 40-1, as shown by act 13-15, and between radio access node network central unit 40-n and radio access network node distributed unit 42-n, as shown by act 13-16.
  • the radio access node network central unit 40-n updates a tunnel between itself and core network 22. Thereafter, as act 13-20, the radio access node network central unit 40-n sends a handover response message to radio access network node distributed unit 42-n.
  • the handover response message of act 13-20 includes the tunnel endpoint identifier CU-N TEID for radio access node network central unit 40-n and the KEYS.
  • the radio access network node distributed unit 42-n as act 13-21 relays the handover response to radio access network node distributed unit 42-1.
  • the radio access network node central unit 40-1 Upon receipt of the handover response of act 13-21, as act 13-22 the radio access network node central unit 40-1 sends a handover command to wireless terminal 30.
  • the handover command of act 13-22 includes identifiers of the radio access network target node distributed unit 42-n, the tunnel endpoint identifiers DU-N TEID and CU-N TEID for the tunnel through packet network 46-n, the KEYS, and access DRBs.
  • the source radio access network node central unit 40-1 sends a handover complete message to target radio access node network central unit 40-n.
  • wireless terminal 30 Upon receipt of the handover command of act 13-22, as act 13-25 wireless terminal 30 essentially executes a handover procedure which involves, e.g., selecting the target distributed unit. As depicted by act 13-25, the wireless terminal 30 performs a random access procedure with the radio access network target node distributed unit 42-n. Assuming that the random access procedure is successful, as act 13-26 the UE-1 context is updated.
  • act 13-27 shows that user plane connectivity and control plane connectivity exists between radio access node network central unit 40-n and core network 22.
  • act 13-28 the temporary tunnel between source radio access network node central unit 40-1 and target radio access node network central unit 40-n is released.
  • act 13-29 shows that user plane connectivity and control plane connectivity exists between target radio access node network central unit 40-n and radio access network node distributed unit 42-n.
  • Act 13-30 depicts MAC-based modification of one or more data radio bearer(s) and signaling radio bearer(s) between wireless terminal 30 and radio access network node distributed unit 42-n.
  • establishment, modification, and release of both signaling radio bearer(s) and data radio bearer(s) is preferably performed by the MAC layer in the technology disclosed herein.
  • DRB/SRB modification both user plane connectivity and control plane connectivity exists between wireless terminal 30 and target radio access node network central unit 40-n, as depicted by act 13-31.
  • act 13-32 shows wireless terminal 30 as again being in connected mode.
  • Fig. 14 is a signal flow diagram showing an inter-control unit connected mode handover/cell re-selection procedure for the radio access network of Fig. 5.
  • Act 14-1 depicts the fact that wireless terminal 30, while in the unprimed position shown at the bottom left of Fig. 5, is in idle mode. Being in idle mode, there is no active current connection involving wireless terminal 30.
  • UE contexts for wireless terminal 30 may exist at each of radio access network node distributed unit 42-1 and radio access network node central unit 40-1, since at the beginning of the scenario wireless terminal 30, although in idle mode, is served by the source node.
  • Act 14-2 shows the distributed unit version of the UE context for wireless terminal 30 as existing at radio access network node distributed unit 42-1; act 14-3 shows the central unit version of the UE context for wireless terminal 30 as existing at radio access network node central unit 40-1. Act 14-3 further shows that the radio access network node central unit 40-1 also knows the endpoints for the tunnel through packet network 46-1 for a previous connection involving wireless terminal 30, e.g., the tunnel endpoint identifiers DU-1 TEID and CU-1 TEID.
  • the wireless terminal 30 While in idle mode (act 14-1), as shown by act 14-7 the wireless terminal 30 makes may detect a new target node, e.g., radio access network node distributed unit 42-n, and may determine that cell re-selection should occur, e.g., that the cell of radio access node network central unit 40-n should be utilized rather than the cell of radio access network node distributed unit 42-1. Such determination may occur, for example, when the wireless terminal 30 moves according to change of connectivity arrow 90 to the primed position 30’ in Fig. 5. Before the movement depicted by change of connectivity arrow 90 the wireless terminal 30 has been served by the source node, e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the source node e.g., radio access network node distributed unit 42-1 and radio access network node central unit 40-1.
  • the detection/determination of act 14-7 may be made on the basis of signal measurements made by wireless terminal 30, from which the terminal connectivity controller 92, for example, may make a determination that wireless terminal 30 would be better served by a target node, e.g., radio access network node distributed unit 42-n and radio access node network central unit 40-n, rather than the source node.
  • the wireless terminal 30 not only determines that cell re-selection should occur, but also ascertains (based on the received measurements) the identity of the radio access network target node distributed unit, which in the illustration scenario is radio access network node distributed unit 42-n.
  • the radio access network target node distributed unit 42-n utilizes a different packet network 46, e.g., packet network 46-n rather than packet network 46-1.
  • act 14-8 the wireless terminal 30 participates in a random access procedure with the radio access network target node distributed unit 42-n.
  • act 14-9 information is exchanged between wireless terminal 30 and radio access network node distributed unit 42-n.
  • the information exchange of act 14-9 provides radio access network node distributed unit 42-n with a UE context for wireless terminal 30, as well as identifiers of the source node entities, e.g., of radio access network node central unit 40-1 and radio access network node distributed unit 42-1, and tunnel endpoints DU-1 and CU-1 previously utilized for a tunnel through packet network 46-1 for wireless terminal 30, as well as KEYS.
  • the radio access network node distributed unit 42-n establishes its context for wireless terminal 30, e.g., UE-1 context, and creates a tunnel endpoint, e.g., DU-N TEID, as one endpoint of a tunnel through packet network 46-n to radio access node network central unit 40-n for wireless terminal 30.
  • a tunnel endpoint e.g., DU-N TEID
  • a tunnel is established through packet network 46-n between target radio access node network central unit 40-n and radio access network target node distributed unit 42-n.
  • the tunnel has the tunnel endpoint identifiers DU-N TEID and CU-N TEID.
  • the radio access network node distributed unit 42-n establishes its context for wireless terminal 30.
  • Act 14-12 also shows that the tunnel endpoint identifier for radio access node network central unit 40-n is CU-N TEID.
  • the radio access node network central unit 40-n After establishing its context for wireless terminal 30, as act 14-13 the radio access node network central unit 40-n establishes a temporary tunnel with source radio access network node central unit 40-1, through which the UE-1 context is retrieved. At this point both user plane connectivity and control plane connectivity exist between radio access node network central unit 40-n and radio access network node distributed unit 42-n, as shown by act 14-14, and between radio access node network central unit 40-n and radio access network node central unit 40-1, as shown by act 14-15.
  • the radio access node network central unit 40-n updates a tunnel between itself and core network 22. Thereafter, both control plane connectivity and user plane connectivity exists between core network 22 and radio access node network central unit 40-n, as shown by act 14-17. Also, both control plane connectivity and user plane connectivity exists between radio access node network central unit 40-n and radio access network node distributed unit 42-n, as shown by act 14-18. As act 14-19 the temporary tunnel between source radio access network node central unit 40-1 and target radio access node network central unit 40-n is released.
  • Act 14-20 reflects and update of context information between radio access network node distributed unit 42-n and wireless terminal 30.
  • the context information for UE-1 context which is updated may include the DU-N keys, the CU-N keys, and the tunnel endpoints DU-N TEID and CU-N TEID.
  • Act 14-21 shows a further update of context, which may include an update of DU-N keys, CU-N TEID, and SRB.
  • act 14-22 the wireless terminal 30 again enters idle mode. Thereafter, user plane connectivity exists between wireless terminal 30 and radio access network node distributed unit 42-n, as shown by act 14-23. Previously a release of channels between radio access network node central unit 40-1 and radio access network node distributed unit 42-1, as shown by act 14-24.
  • the technology disclosed herein advantageously reduces signaling and expedites session establishment, re-establishment, resume, and ON-OFF operations. For example, upon handover from one distributed processor circuitry site to another, including differing radio access network node distributed units served by differing radio access network node central units and through differing packet networks, the procedures are simplified, resulting in significant savings and efficiency.
  • Certain units and functionalities of virtualized radio access network 24 may be implemented by electronic machinery.
  • electronic machinery may refer to the processor circuitry described herein, such as anchor processor circuitry 40 and distributed processor circuitry 42, and RAN processing circuitry 92.
  • processor circuitry is not limited to mean one processor, but may include plural processors, with the plural processors operating at one or more sites.
  • server as used herein the term “server”, as in plural anchor processor circuitry servers 40 , is not confined to one server unit, but may encompasses plural servers and/or other electronic equipment, and may be co-located at one site or distributed to different sites.
  • processor circuitry as comprising one or more processors 190, program instruction memory 192; other memory 194 (e.g., RAM, cache, etc.); input/output interfaces 196 and 197, peripheral interfaces 198; support circuits 199; and busses 200 for communication between the aforementioned units.
  • the processor(s) 190 may comprise the processor circuitries described herein, for example, the anchor processor circuitry 40 and distributed processor circuitry 42 distributed processor circuitry 42.
  • the memory 194, or computer-readable medium may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, flash memory or any other form of digital storage, local or remote, and is preferably of non-volatile nature, as and such may comprise memory 60 shown in Fig. 5.
  • the support circuits 199 are coupled to the processors 190 for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuitry and subsystems, and the like.
  • the processes and methods of the disclosed embodiments may be discussed as being implemented as a software routine, some of the method steps that are disclosed therein may be performed in hardware as well as by a processor running software. As such, the embodiments may be implemented in software as executed upon a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or a combination of software and hardware.
  • the software routines of the disclosed embodiments are capable of being executed on any computer operating system, and is capable of being performed using any CPU architecture.
  • the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) [ASIC], and/or field programmable gate array(s) (FPGA(s)), and (where appropriate) state machines capable of performing such functions.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein.
  • the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed.
  • processor or “controller” may also be construed to refer to other hardware capable of performing such functions and/or executing software, such as the example hardware recited above.
  • Nodes that communicate using the air interface also have suitable radio communications circuitry.
  • the technology disclosed herein may additionally be considered to be embodied entirely within any form of computer-readable memory, such as solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein.
  • each functional block or various features of the wireless terminal 30 and virtualized radio access network 24 used in each of the aforementioned embodiments may be implemented or executed by circuitry, which is typically an integrated circuit or a plurality of integrated circuits.
  • the circuitry designed to execute the functions described in the present specification may comprise a general-purpose processor, a digital signal processor (DSP), an application specific or general application integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic, or a discrete hardware component, or a combination thereof.
  • the general-purpose processor may be a microprocessor, or alternatively, the processor may be a conventional processor, a controller, a microcontroller or a state machine.
  • the general-purpose processor or each circuit described above may be configured by a digital circuit or may be configured by an analogue circuit. Further, when a technology of making into an integrated circuit superseding integrated circuits at the present time appears due to advancement of a semiconductor technology, the integrated circuit by this technology is also able to be used.
  • Example Embodiment 1 A radio access network comprising: a radio access network source node central unit; a radio access network target node central unit; a radio access network source node distributed unit connected with the radio access network source node central unit over a first packet data domain; a radio access network target node distributed unit connected with the radio access network target node central unit over a second packet data domain; a wireless terminal configured to communication across a radio interface with one or both of the radio access network source node distributed unit and the radio access network target node distributed unit; and processor circuitry configured to change at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • Example Embodiment 2 The radio access network of Example Embodiment 1, wherein the radio access network source node central unit and the radio access network target node central unit are configured to perform a high layer radio access network node operation; wherein the radio access network source node distributed unit and the radio access network target node distributed unit are configured to perform a low layer radio access network node operation.
  • Example Embodiment 3 The radio access network of Example Embodiment 1, wherein the wireless terminal is in idle mode, and wherein the processor circuitry comprises the wireless terminal and is configured to perform a cell re-selection procedure wherein the wireless terminal detects a transmission of the radio access network target node distributed unit and initiates a random access procedure to the radio access network target node distributed unit.
  • Example Embodiment 4 The radio access network of Example Embodiment 1, wherein the wireless terminal is in connected mode, and wherein the processor circuitry is configured to request a handover/determine a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • Example Embodiment 5 The radio access network of Example Embodiment 3, wherein the processor circuitry is situated at the radio access network source node central unit.
  • Example Embodiment 6 The radio access network of Example Embodiment 3, wherein the processor circuitry is situated at the wireless terminal.
  • Example Embodiment 7 The radio access network of Example Embodiment 3, wherein the processor circuitry is situated at the radio access network source node distributed unit.
  • Radio access network source node central unit comprising: an interface to radio access network source node distributed unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; an interface to radio access network target node central unit which is connected to a radio access network target node distributed unit via a second packet data domain; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • Radio access network source node distributed unit comprising: an interface to radio access network source node central unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; transceiver circuitry configured to transmit and receive communications over a radio interface with the wireless terminal; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to radio access network target node distributed unit, the radio access network target node distributed unit being connected to radio access network target node central unit via a second Packet data domain.
  • Example Embodiment 10 A wireless terminal comprising: an interface to radio access network source node central unit to which the radio access network source node central unit is connected by a first packet data domain and through which the radio access network source node central unit communicates with a wireless terminal in connected mode; transceiver circuitry configured to transmit and receive communications over a radio interface with radio access network source node distributed unit and radio access network target node distributed unit, the radio access network source node distributed unit being connected by a first packet data domain to radio access network source node central unit; the radio access network target node distributed unit being connected by a second Packet data domain to radio access network target node central unit; processor circuitry configured to initiate a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to radio access network target node distributed unit.
  • Example Embodiment 11 A method in a radio access network comprising: making a determination that a wireless terminal should be handed over from radio access network source node distributed unit to radio access network target node distributed unit, the radio access network source node distributed unit being connected to radio access network source node central unit over a first packet data domain, the radio access network target node distributed unit being connected to radio access network target node central unit over a second packet data domain in accordance with the determination, changing at least control plane connectivity of the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit and thereby routing control plane signaling for the wireless terminal through the second packet data domain.
  • Example Embodiment 12 The method of Example Embodiment 11, further comprising using processor circuitry to make the determination that a wireless terminal should be handed over from radio access network source node distributed unit to radio access network target node distributed unit.
  • Example Embodiment 13 The method of Example Embodiment 11, wherein the wireless terminal is in idle mode, and wherein the wireless terminal is configured to perform a cell re-selection procedure wherein the wireless terminal detects a transmission of the radio access network target node distributed unit and initiates a random access procedure to the radio access network target node distributed unit.
  • Example Embodiment 14 The method of Example Embodiment 11, wherein the wireless terminal is in connected mode, and further comprising requesting a handover/determining a handover of a connection involving the wireless terminal from the radio access network source node distributed unit to the radio access network target node distributed unit.
  • Example Embodiment 15 The radio access network of Example Embodiment 11, further comprising making the determination at the radio access network source node central unit.
  • Example Embodiment 16 The radio access network of Example Embodiment 11, further comprising making the determination at the wireless terminal.
  • Example Embodiment 17 The radio access network of Example Embodiment 11, further comprising making the determination at the radio access network source node distributed unit.
  • the technology disclosed herein is directed to solving radio communications-centric issues and is necessarily rooted in computer technology and overcomes problems specifically arising in radio communications. Moreover, the technology disclosed herein improves basic function of a radio access network, e.g., enabling faster and simplified operations such expedited network access.

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

Abstract

La présente invention concerne un réseau d'accès radio virtualisé comprenant une unité centrale de nœud source de réseau d'accès radio; une unité centrale de nœud cible de réseau d'accès radio; une unité distribuée de nœud source de réseau d'accès radio; une unité distribuée de nœud cible de réseau d'accès radio; un terminal sans fil; et un circuit de traitement contrôlant le changement de connectivité. L'unité distribuée de nœud source de réseau d'accès radio est connectée à l'unité centrale de nœud source de réseau d'accès radio sur un premier domaine de données de paquet. L'unité distribuée de nœud cible de réseau d'accès radio est connectée à l'unité centrale de nœud cible de réseau d'accès radio sur un second domaine de données de paquet. Le terminal sans fil est configuré pour communiquer à travers une interface radio avec l'une ou les deux parmi l'unité distribuée de nœud source de réseau d'accès radio et l'unité distribuée de nœud cible de réseau d'accès radio. Le circuit de traitement de contrôle de la connectivité est configuré pour changer au moins la connectivité du plan de contrôle du terminal sans fil de l'unité distribuée du nœud source du réseau d'accès radio à l'unité distribuée du nœud cible du réseau d'accès radio.
PCT/JP2019/042683 2018-11-09 2019-10-30 Réseau et procédés pour prendre en charge une mobilité inter-domaine dans un réseau d'accès radio virtualisé WO2020095804A1 (fr)

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