SIGNALING TOWARDS CORE NETWORK WITH A BI-DIRECTIONAL TUNNEL

BACKGROUND: Field:

[0001 ] Various communication systems may benefit from improved signaling towards a core network. For example, networks may benefit from reduced signaling towards a core network when a user equipment selects a new cell.

Description of the Related Art:

[0002] 5 ^th generation (5G) telecommunications is a new generation of radio systems and network architecture that can deliver extreme broadband and ultra-robust, low latency connectivity. 5G allows for massive machine-to-machine connectivity for the Internet of Things (loT). 5G can also improve the telecommunication services offered to the end users, and help support various industry evolved servicers. For example, industrial control, vehicular safety, transport system efficiency, and eHealth applications may all be improved by the implementation of 5G.

[0003] The handling of user equipment and network entities in different operation states is also improved in 5G. In other networks, for example, Third Generation Partnership Project (3GPP) Long Term Evolution (LTE), a user equipment (UE) can be in an idle state or a connected state. In 5G networks, however, the UE may be in an idle state, a connected state, or inactive connected state. The UE states in 5G allow for a more efficient resource usage, better network access timing, and improved energy efficiency.

[0004] In contrast to the idle state, the inactive connected state keeps the UE connected to the core network, even during low activity periods. The radio link layer control for a UE in an inactive connected state is handed over from one cell or base station to another cell or base station when the UE is relocated. Because the core network sees a UE in an inactive connected state as always being connected to the core network, it can result in frequent relocation of the serving base station and data path switching. This frequent signaling may cause a signaling load problem. SUMMARY:

[0005] A method, in certain embodiments, may include receiving a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The method can also include establishing a tunnel between the first network node and the second network node. In addition, the method can include exchanging data between the first network node and a core network entity. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0006] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to receive a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to establish a tunnel between the first network node and the second network node. In addition, the at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to exchange data between the first network node and a core network entity. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0007] An apparatus, in certain embodiments, may include means for receiving a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The apparatus may also include means for establishing a tunnel between the first network node and the second network node. In addition, the apparatus may include means for exchanging data between the first network node and a core network entity. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0008] According to certain embodiments, a non-transitory computer-readable medium may include encoding instructions that, when executed in hardware, perform a process. The process may include receiving a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The process may also include establishing a tunnel between the first network node and the second network node. In addition, the process may include exchanging data between the first network node and a core network entity. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0009] According to certain embodiments, a computer program product may include encoding instructions for performing a process according to a method including receiving a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The method may also include establishing a tunnel between the first network node and the second network node. In addition, the method may include exchanging data between the first network node and a core network entity. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0010] A method, in certain embodiments, may include sending a connection request from a user equipment in an inactive connected state to a second network node. A tunnel is established between a first network node and the second network node. The method may also include connecting to the second network node. In addition, the method may include exchanging data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment.

[0011] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to send a connection request from a user equipment in an inactive connected state to a second network node. A tunnel is established between a first network node and the second network node. The at least one memory and the computer program code may also be configured, with the at least one processor, at least to connect to the second network node. In addition, the at least one memory and the computer program code may also be configured, with the at least one processor, at least to exchange data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment.

[0012] An apparatus, in certain embodiments, may include means for sending a connection request from a user equipment in an inactive connected state to a second network node. A tunnel is established between a first network node and the second network node. The apparatus may also include means for connecting to the second network node. In addition, the apparatus may include means for exchanging data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment.

[0013] According to certain embodiments, a non-transitory computer-readable medium may include encoding instructions that, when executed in hardware, perform a process. The process may include sending a connection request from a user equipment in an inactive connected state to a second network node. A tunnel is established between a first network node and the second network node. The process may also include connecting to the second network node. In addition, the process may include exchanging data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment

[0014] According to certain embodiments, a computer program product may include encoding instructions for performing a process according to a method including sending a connection request from a user equipment in an inactive connected state to a second network node. A tunnel is established between a first network node and the second network node. The method may also include connecting to the second network node. In addition, the method may include exchanging data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment.

[0015] A method, in certain embodiments, may include receiving a connection request at a second network node from a user equipment in an inactive connected state. The method can also include establishing a tunnel between a first network node and the second network node. In addition, the method can include connecting to the user equipment. Further, the method may include exchanging data between the second network node and a core network entity through the tunnel. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0016] According to certain embodiments, an apparatus may include at least one memory including computer program code, and at least one processor. The at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to receive a connection request at a second network node from a user equipment in an inactive connected state. The at least one memory and the computer program code may also be configured, with the at least one processor, to cause the apparatus at least to establish a tunnel between a first network node and the second network node. In addition, the at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to connect to the user equipment. Further, the at least one memory and the computer program code may be configured, with the at least one processor, to cause the apparatus at least to exchange data between the second network node and a core network entity through the tunnel. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0017] An apparatus, in certain embodiments, may include means for receiving a connection request at a second network node from a user equipment in an inactive connected state. The apparatus may also include means for establishing a tunnel between a first network node and the second network node. In addition, the apparatus may include means for connecting to the user equipment. Further, the apparatus may also include means for exchanging data between the second network node and a core network entity through the tunnel. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0018] According to certain embodiments, a non-transitory computer-readable medium may include encoding instructions that, when executed in hardware, perform a process. The process may include receiving a connection request at a second network node from a user equipment in an inactive connected state. The process may also include establishing a tunnel between a first network node and the second network node. In addition, the process may include connecting to the user equipment. Further, the process may include exchanging data between the second network node and a core network entity through the tunnel. The first network node operates as an anchor node after the user equipment has connected to the second network node.

[0019] According to certain embodiments, a computer program product may include encoding instructions for performing a process according to a method including receiving a connection request at a second network node from a user equipment in an inactive connected state. The method may also include establishing a tunnel between a first network node and the second network node. In addition, the method may include connecting to the user equipment. Further, the method may include exchanging data between the second network node and a core network entity through the tunnel. The first network node operates as an anchor node after the user equipment has connected to the second network node.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0020] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0021 ] Figure 1 illustrates a signal diagram according to certain embodiments.

[0022] Figure 2A illustrates a signal flow diagram.

[0023] Figure 2B illustrates a signal flow diagram.

[0024] Figure 3A illustrates a signal flow diagram according to certain embodiments.

[0025] Figure 3B illustrates a signal flow diagram according to certain embodiments.

[0026] Figure 4 illustrates a flow diagram according to certain embodiments.

[0027] Figure 5 illustrates a flow diagram according to certain embodiments.

[0028] Figure 6 illustrates a flow diagram according to certain embodiments.

[0029] Figure 7 illustrates a system according to certain embodiments. DETAILED DESCRIPTION:

[0030] Certain embodiments provide for a method, apparatus, computer program, or other embodiments for improving the management of a radio access network (RAN). The framework can provide for the intelligent control the relocation of the serving base station (BS) to a new base station. This can reduce at least one of the frequency of UE BS context transfers, user plane switching, or signaling towards the core network. In one embodiment, signaling can be reduced when the UE selects a new cell, and when the UE transitions a radio resource control (RRC) state. For example, the RRC state may transition from an inactive connected state to a connected state due to user plane data activity and/or dedicated signaling.

[0031 ] Certain embodiments may utilize an on demand procedure that includes a user plane tunnel or an extension tunnel between the last serving BS and the current BS, in the selected target cell. The tunnel or extension tunnel may be bi-directional. In certain embodiments, the tunnel may be used to transfer data between network nodes when the UE has relocated to a new cell and/or the UE transitions from an RRC inactive connected state to an RRC connected state. For example, the tunnel, which may be referred to as an extension tunnel, may be similar to an X2 inter BS tunnel. The tunnel, however, can have various features and functionality that are not available in the LTE X2 tunnel.

[0032] In certain other embodiments, user data to and/or from the core network can be routed via the last serving BS. In other words, the last serving BS may continue to operate as a RAN anchor node, storing full UE BS context data, and keeping one or more user plane data paths intact towards the core network. This can result in less frequent relocations of the serving network node. For example, the last serving BS may not have to transfer the full UE BS context data and switch the user plane paths that connect the last serving BS to the core network. This can allow for the efficient management and decoupling of the control plane state and the user plane connectivity.

[0033] The last serving BS, in some embodiments, may have the ability to decide when relocation of the serving BS can be beneficial. In other embodiments, another entity in the network, which is separate from the last serving BS, may decide whether the relocation of the serving BS can be beneficial. Some criteria for determining whether relocation is beneficial may include a UE location, a cell type, cell loading information, and network congestion information. In certain embodiments, the serving BS relocation may be postponed altogether, and the last serving BS can continue to operate as a RAN anchor node. In such an embodiment there may be no need to signal anything to the core network, until the last serving BS decides to abdicate its RAN anchor functionality.

[0034] An inactive connected state can be a 5G UE state in which the UE may always be connected to the core network, even during low activity periods. When the UE is handed over from one cell or BS to another, the radio link layer control for the UE in an inactive connect state can be handed over as well. The UE movements in an inactive connected state can be known or exposed to the core network, and may result in serving BS relocation and data path switching. This relocation and switching may occur even without data being transmitted through the current cell or BS.

[0035] Certain embodiments allow for controlling the serving BS relocation and/or path switch when a UE needs user-plane connectivity to send data. Some other embodiments allow for controlling the serving BS relocation when the UE has moved out of a certain tracking area, or to a topology location that benefits from data path optimization. While some embodiments may utilize a 5G network, other embodiments may utilized in an LTE network or any other network in which the embodiments may be integrated.

[0036] Figure 1 illustrates a signal diagram according to certain embodiments. In particular, Figure 1 illustrates a UE state model for the 5G RAN including three discrete states. The UE may have one of the following three states: RRC Idle state 1 10, RRC Inactive Connected state 120, or RRC Connected state 130. While other states, as well as the number of states themselves, may also be possible, Figure 1 is focused on the three specified states.

[0037] In an RRC Idle state 1 10, the UE saves power and may not inform the network of each cell change. The network may know the location of the UE through the granularity of at least one cell known as the tracking area. The UE can perform a cell update when reselecting to a new cell. The UE may also detect incoming traffic, perform cell selection and/or reselection, and acquire system information. Unicast data transfer with a UE in an RRC Idle state 1 10, however, may not be possible. To transition between RRC Idle state 1 10 and RRC Connected state 130, the UE would have to connect to the core network. On the other hand, to transition between RRC Connected state 130 and RRC Idle state 1 10, the UE would have to release its connection to the core network.

[0038] An RRC Inactive Connected state 120 may be the primary state which optimizes data inactivity. During low activity states both the UE and the network can keep RAN context information configured during the RRC connection setup. In an RRC Inactive Connected state 120, the UE can remain connected to the core network. Because the core network can perceive the UE in an RRC Inactive Connected state as being in a connected state, the UE's movements may be exposed to the core network as if the UE were in a connected state 130.

[0039] To transition from an RRC Inactive Connected state 120 to an RRC Connected state 130, the UE simply resumes the connection that has previously been suspended. On the other hand, to transition from an RRC Inactive Connected state 120 to an RRC Idle state 1 10, the UE may release its connection to the core network, similar to the transition from then RRC Connected state 130 to RRC Idle state 1 10. In certain embodiments, a UE can directly transition from RRC Idle state 1 10 to the RRC Connected state 130.

[0040] RRC Connected state 130 may be a state in which the UE transfers unicast control and/or data in the uplink or downlink to the core network. The location of the UE may be known to the core network at a cell level. In addition, the UE may monitor control channels, provide channel quality and feedback information, perform neighboring cell measurements and reporting, and acquire system information. To transition from RRC Connected state 130 to RRC Idle state 1 10, the UE can release its connection to the core network. To transition from RRC Connected state 130 to RRC Inactive Connected state 120, however, the connection to the core network can merely be suspended, rather than released.

[0041 ] Certain embodiments may allow the UE to transmit in an uplink channel using contention-based uplink transmission without changing the UE state. In some embodiments, the UE may be in an RRC Inactive Connected state 120, and the UE can use the uplink contention-based transmission resource pool allocated by the RAN anchor node without having to experience a serving BS relocation and/or a path switch. When receiving the contention-based uplink transmission from UE, a tunnel may be established between a first network node and a second network node, and the data can be sent from the user equipment to the second network node. The data may subsequently be forwarded to the first network node through the tunnel.

[0042] Certain embodiments help reduce or limit the signaling between the UE and the network core when the UE selects a new cell, and transitions between the different states shown in Figure 1 . Some embodiments may also help to reduce or limit signaling between the UE and the network core when the UE is in an RRC Inactive Connected state 120, and the UE is handed over to a new cell or BS.

[0043] Figure 2A illustrates a signal flow diagram. Specifically, the embodiment in Figure 2A illustrates a UE selecting a new cell while in the RRC Inactive Connected state. Figure 2A may also illustrate a case where network node 202, which may be the last serving BS, relocates its serving functionality to network node 203, which may be the new BS. In step 1 , UE 201 may be connected to a network node 202, for example, a 5G nodeB, in a first cell. In other embodiments, the network node may be any other type of network node or base station. Network node 202 may be known as the last serving cell. The network node 202 may serve the UE 201 , and act as an RAN anchor node. An RAN anchor node, for example, may be responsible for communicating or anchoring data between the UE 202 to the core network. [0044] In step 2, UE 201 may be relocated to a second cell. The relocation of the UE may be initiated by the selection of the new cell by the UE. For example, the UE may select a new cell due to the movement of the UE, the quality of service offered by the newly selected cell, or for any other reason. In some embodiments, upon selecting the second cell in step 2, UE 201 may transition from an RRC Inactive Connected state to an RRC Connected state, as explained in Figure 1 . The transition may be the result of UE 201 wanting to send or receive user data to the core network.

[0045] In step 3.1 , UE 201 sends an RRC connection request to network node 203, for example a 5G-NB, in the second cell. Certain embodiments may involve an X2 based handover. The X2 interface may be similar to an LTE X2 interface, and may provide a connection between two base stations in two different cells. In those embodiments, network node 203 in the second cell may send a notification to the current serving network node 202 in step 3.2 informing network node 202 that the UE has selected the second cell.

[0046] In step 4.1 , network node 202 may send a message to network node 203, in which network node 202 abdicates its responsibilities as the serving node. In addition, network node 202 may transfer all RAN anchor functions to network node 203. Because Figure 2A can illustrate a case where the last serving BS or network node 202 relocates its serving BS function to new BS or network node 203, step 4.1 can be a message containing the transferred UE context data.

[0047] Network node 203 can then send an RRC Connection confirmation message to UE 201 in step 4.2. In certain embodiments the UE 201 may now complete the transition to an RRC Connected state. Once the RRC connection is established between the UE 201 and network node 203, network node 203 starts acting as the RAN Anchor. Therefore, UE 201 may send data to a core network entity through network node 203, without the involvement of any other network node. As shown in step 6 of Figure 2B, UE 201 sends data to network node 203 which facilitates communication with the core network.

[0048] Mobility Management Entity (MME) and Mobility and Session Manager (MSM) may be examples of a core network entity. After network node 203 has moved UE 201 to RRC Connected State, in step 4.1 , it may send a notification to MSM 204 in step 5.1 . The notification may inform MSM 204 that UE 201 has selected a new cell, and that network node 203 has started to operate as a serving BS for UE 201 . In step 5.21 , MSM may send an acknowledgment to network node 203, that the MSM 204 will switch its S1 interfaces from network node 202 to new serving network node 203.

[0049] In step 5.22, the S1 interface in the user plane (S1 -U), which may act as an interface between network node 202 and user gateway (uGW) 205, may be moved to connect network node 203 and uGW 205. Similarly, in step 5.23, the S1 interface in the control plane (S1 -C), which may interface between network node 202 and MSM 204, may transition from network node 202 to network node 203.

[0050] Figure 2B illustrates a signal flow diagram. Once the transition illustrated in Figure 2A is completed, network node 203 may be the only node needed for UE 201 to communicate with the core network. In other words, network node 203 may become the new serving network node. In addition, network node 203 may also become the new RAN anchor node. As seen in step 6, UE 201 may send data to uGW 205 through network node 203. Network node 202 at this point is not connected to UE 201 , and can act as a neighboring cell.

[0051 ] As shown in Figure 2A, the relocation of UE 201 and the transition of UE from an RRC Inactive Connected state to an RRC Connected state, in step 2, may be taxing. In other words, step 2 necessitates various signaling between the involved network nodes and the core network entities. Certain embodiments may act to limit or reduce this signaling to the core network. Some embodiments can also reduce the frequency of switching serving network nodes or RAN anchors.

[0052] Figure 3A illustrates a signal flow diagram according to certain embodiments. Specifically, Figure 3A illustrates the use of a tunnel or an extension tunnel between a network node in a previous cell and a network node in a newly selected cell. In certain embodiments, UE 301 may be in an inactive connected state. In some other embodiments UE 301 may be transitioning from an RRC Inactive Connected state to a RRC Connected state. The mobility and reachability of UE 301 can be monitored by the RAN, which may include Tracking Area management function. In some embodiments, the cell can change during an RRC Inactive Connected state based on cell selection or reselection initiated by UE 301 .

[0053] In step 1 , UE 301 may be connected to first network node 302, for example, a 5G- NB, in a first cell. In certain embodiments, UE 301 may transition from a connected to an inactive connected state. The transition of the connected state of the UE 301 may be hidden from the core network because UE 301 remains connected to first network node 302. In other words, even after the transition to the inactive connected state, the UE may perceive the UE as still being in a connection, and the S1 -C and S1 -U connections can remain intact. First network node 302 can maintain its UE BS context data, and also maintain its role as the RAN anchor node.

[0054] In step 2, UE 301 may select a new cell while in an RRC Inactive Connected state. UE 301 can then sends a connection request, for example, an RRC Resume Request, to second network node 303 located in the newly selected cell 2, in step 3.1 . The UE may include a Reconnect cause value in the request. In step 3.2, second network node 303 may forward the UE request to first network node 302, also known as the last serving network node. In certain embodiments of step 3.2, second network node 303 may include at least one downlink tunnel endpoint parameter in the message sent in step 3.2. The downlink endpoint parameter may, for example, be an IP address of network node 303, or a tunnel endpoint identifier. First network node 302 may use the at least one downlink tunnel endpoint parameter to establish the tunnel. In other words, second network node 303 may provide first network node 302 with parameters for the establishment of a tunnel between second network node 303 and first network node 302.

[0055] First network node 302 may then decide whether or not to keep the serving network node functions, and may send a Context Transfer message to second network node 303, also known as the secondary network node, in step 4.1 . Second network node 303 may be known as a secondary network node because in some embodiments it may not be the acting serving network node or the RAN anchor. For example, even when UE 301 moves to a new cell, second network node 303 of the old network node 302 may continue to act as the serving node and/or the RAN anchor. Doing so can help reduce the amount of signals sent to the core network because core network may not be aware of new second network node 303, and may still perceive first network node 302 as being the only network node serving the UE.

[0056] In step 4.1 , first network node 302 may send a message to second network node 303 that includes at least one uplink tunnel endpoint parameter for the tunnel. The at least one uplink tunnel endpoint parameter can allow second network node 303 to establish the tunnel. Steps 3.2 and 4.1 can therefore be used by first network node 302 and second network node 303 to establish a bi-directional tunnel between the two nodes. The tunnel can have a variety of functions that are not present in the current LTE X2 interface. For instance, the tunnel may continue to connect first network node 302 and second network node 303 even after an RRC connection has been established between UE 301 and second network node 303. The tunnel can aid communication between second network node 303 and first network node 302, and help first network node 302 remain as the RAN anchor.

[0057] Upon receiving the message from first network node 302, second network node 303 may send a confirmation or acknowledgement message to UE 301 , in step 4.2. For example, second network node 303 may send an RRC Connection Resume Complete message to UE 301 . In some embodiments, once UE receives such a message it may complete its transition from an RRC Inactive Connected state to an RRC Connected state. The transition may be initiated when UE 301 sends second network node 303 a request in step 3.1 , and the transition may be completed when UE 301 receives a confirmation in step 4.2 from second network node 303.

[0058] UE 301 may have user-plane connectivity to the core network through first network node 302. The tunnel connecting first network node 302 and second network node 303 helps to facilitate this connectivity, as well as the already existing S1 -U interface that exists between first network node 302 and uGW 305. Alternatively, the UE may access any other network entity, for example, MSM 304, in the network core.

[0059] Because the serving or the RAN anchor functions of first network node 302 remain intact, the UE low activity state and following state transition to RRC Connected state may remain hidden from the core network. The core network can in some embodiments only perceive that first network node 302 is still the serving node and RAN anchor. By keeping the serving or the RAN anchor functions of first network node 302 intact, signaling and data path switching related to a network node relocation may be reduced, or in some embodiments even omitted.

[0060] Figure 3B illustrates a signal flow diagram according to certain embodiments. As illustrated in Figure 3B, data may be exchanged between UE 301 and a core network entity, for example, MSM 304, as shown in step 5. When the data originates at the UE, the data may be routed through the tunnel, between second network node 303 and first network node 302, and then transmitted to the core network through first network node 302, which is the last serving BS. The first network node 302 continues to operate as the RAN anchor, meaning that first network node 302 may store the full UE BS context data, as well as keep the user-plane data path intact towards the core network.

[0061 ] In certain embodiments, data that originates in an entity in the network core may also be sent to the UE via the existing RAN anchor, shown as first network node 302 in Figure 3B, through the tunnel. In such embodiments, the tunnel may be bi-directional, allowing for the transmission of data to and from UE 301 , as well as to and from network nodes 302 and 303.

[0062] Figure 4 illustrates a signal flow diagram according to certain embodiments. Specifically, Figure 4 can illustrate signaling from the perspective of first network node 302 in Figures 3A and 3B, also known as the last serving BS. In step 410, the first network node may receive a request to connect to a second network node. The request may originate from a UE in an inactive connected state which has selected a new cell in which the second network node is located. Upon receiving the request, the first network node may decide to remain as the RAN anchor node, and keep its serving node functionality, despite the relocation of the UE.

[0063] In step 420 the first network node may establish a tunnel between the first network node and the second network node. The first network node may use at least one downlink tunnel endpoint parameter received from the second network node to establish the tunnel. The tunnel may be used to send data between the two nodes. From the perspective of the core network, because the first network node can maintain its role as the RAN anchor, as well as keep its serving functionality, the core network can perceive that the UE as being located in a cell in which the first network node resides.

[0064] In step 430, the first network node may exchange data with the core network entity. The exchange may include either receiving data from an entity in the core network, or sending data to an entity in the core network. The first network node will continue to act as the RAN anchor or the anchor node even after the UE has connected to the second network node.

[0065] In step 440, the first network node may decide to relocate its anchor node functions to the second network node. The decision may be based on at least the location of the user equipment, a cell type, cell load information, or network configuration information.

[0066] Figure 5 illustrates a signal flow diagram according to certain embodiments. Specifically, Figure 5 can illustrate signaling from the perspective of a user equipment 301 as shown in Figures 3A and 3B. The UE may be in an inactive connected state. After the selection of a new cell, and after transitioning from an RRC Inactive Connected state to an RRC Connected state, as shown in step 510, the UE may send a connection request to a second network node, in step 520. A tunnel may then be established between a first network node and the second network node. In step 530, the UE connects to the second network node. The user equipment may then exchange data with a core network entity, in step 540.

[0067] If the data originates at the UE, the data may be sent from the UE to the second network node. The data may then be forwarded from the second network node to the first network node through the tunnel. The first network node, acting as the RAN anchor, may then send the data to a network entity in the core network. On the other hand, if the data originates at the core network, it will be sent to the first network node. The first network node will then forward the data through the tunnel to the second network node. The UE may then receive the data from the second network node.

[0068] Figure 6 illustrates a signal flow diagram according to certain embodiments. Specifically, Figure 6 can illustrate signaling from the perspective of the second network node 303 in Figures 3A and 3B, also known as the target network node or the secondary network node. In step 610, the second network node may receive a connection request from a user equipment in an inactive connected state. The second network node may then send a notification to the first network node, for example, step 3.2 in Figure 3A, and establish a tunnel between the first network node and the second network node, as recited in step 620.

[0069] In step 630, the second network node may connect to the user equipment. The second network node may then begin to exchange data between the second network node and a core network entity through the tunnel, as shown in step 640. If the data originates in the UE the second network node will receive the data from the UE, and forward the data to the core network through the tunnel and the first network node. If the data originates at the core network entity, the second network node will receive the data from the first network node through the tunnel, and send the data to the user equipment.

[0070] Figure 7 illustrates a system according to certain embodiments. It should be understood that each signal in Figures 3A and 3B and block in Figures 4, 5, and 6 may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, network node 720 or UE 710. The system may include more than one UE 710 and more one network node 720, although only one access node shown for the purposes of illustration. A network node may be an access node, a base station, a 5G-NB, an eNB, server, host, or any of the other access or network node discussed herein.

[0071 ] Each of these devices may include at least one processor or control unit or module, respectively indicated as 71 1 and 721 . At least one memory may be provided in each device, and indicated as 712 and 722, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceiver 713 and 723 may be provided, and each device may also include an antenna, respectively illustrated as 714 and 724. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. Other configurations of these devices, for example, may be provided. For example, network node 720 and UE 710 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 714 and 724 may illustrate any form of communication hardware, without being limited to merely an antenna.

[0072] Transceivers 713 and 723 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. The operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One possible use is to make a network node deliver local content. One or more functionalities may also be implemented as virtual application(s) in software that can run on a server.

[0073] A user device or user equipment 710 may be a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof.

[0074] In some embodiment, an apparatus, such as a network node, may include means for carrying out embodiments described above in relation to Figures 3A, 3B, 4, 5, and 6. In certain embodiments, at least one memory including computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform any of the processes described herein.

[0075] According to certain embodiments, an apparatus 720 may include at least one memory 722 including computer program code, and at least one processor 721 . The at least one memory 722 and the computer program code are configured, with the at least one processor 721 , to cause the apparatus 720 at least to receive a request at a first network node from a user equipment in an inactive connected state to connect to a second network node. The at least one memory 722 and the computer program code may be configured, with the at least one processor 721 , to also cause the apparatus 720 at least to establish a tunnel between the first network node and the second network node. In addition, the at least one memory 722 and the computer program code may be configured, with the at least one processor 721 , to cause the apparatus 720 at least to exchange data between the first network node and a core network entity. The first network node can operate as an anchor node after the user equipment has connected to the second network node.

[0076] According to certain embodiments, an apparatus 720 may include at least one memory 722 including computer program code, and at least one processor 721 . The at least one memory 722 and the computer program code are configured, with the at least one processor 721 , to cause the apparatus 720 at least to receive a connection request at a second network node from a user equipment in an inactive connected state. The at least one memory 722 and the computer program code may be configured, with the at least one processor 721 , to also cause the apparatus 720 at least to establish a tunnel between a first network node and the second network node. In addition, the at least one memory 722 and the computer program code may be configured, with the at least one processor 721 , to cause the apparatus 720 at least to connect to the user equipment. Further, the at least one memory 722 and the computer program code may be configured, with the at least one processor 721 , to cause the apparatus 720 at least to exchange data between the second network node and a core network entity through the tunnel. The first network node can operate as an anchor node after the user equipment has connected to the second network node.

[0077] According to certain embodiments, an apparatus 710 may include at least one memory 712 including computer program code, and at least one processor 71 1 . The at least one memory 712 and the computer program code are configured, with the at least one processor 71 1 , to cause the apparatus 710 at least to send a connection request from a user equipment in an inactive connected state to a second network node. A tunnel may be established between a first network node and the second network node. The at least one memory 712 and the computer program code may be configured, with the at least one processor 71 1 , to also cause the apparatus 710 at least to connect to the second network node. In addition, the at least one memory 712 and the computer program code may be configured, with the at least one processor 71 1 , to cause the apparatus 710 at least to connect to the user equipment. Further, the at least one memory 712 and the computer program code may be configured, with the at least one processor 71 1 , to cause the apparatus 710 at least to exchange data between the user equipment and a core network entity through the tunnel. The first network node operates as an anchor node to the user equipment.

[0078] Processors 71 1 and 721 may be embodied by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors.

[0079] For firmware or software, the implementation may include modules or unit of at least one chip set (for example, procedures, functions, and so on). Memories 712 and 722 may independently be any suitable storage device, such as a non-transitory computer- readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

[0080] The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as network node 720 or UE 710, to perform any of the processes described above (see, for example, Figures 3A, 3B, 4, 5, and 6). Therefore, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments may be performed entirely in hardware.

[0081 ] Furthermore, although Figure 7 illustrates a system including a network node 720 and UE 710, certain embodiments may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network entities may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and a network entity, such as a relay node. The UE 710 may likewise be provided with a variety of configurations for communication other than communication network node 520. For example, the UE 710 may be configured for device-to-device communication.

[0082] In certain embodiments, a core network signaling load resulting from frequent relocation information updates can be reduced. Some embodiments also allow for the decoupling of the control plane state and the user plane connectivity in an efficiently managed manner. In certain embodiments, the serving BS relocation may be postponed, and the last serving BS can continue its operation as a RAN anchor node. As such, there may be no need to signal the core network, even when the UE has moved to a new cell. This can be particularly helpful in cases of small data transmission.

[0083] Certain embodiments also allow for the UE relocation to be done intelligently. The UE relocation may be based on the system access latency requirements supporting different UE service identities and activities in UEs that are always connected, for example, UEs in the RRC Inactive Connected state. When the UE is in the RRC Inactive Connected state, the core network may perceive the UE as always being connected, and the RAN handles the inactivity of the UE. This can help to reduce the signaling between the core network and the RAN.

[0084] Further, when the UE does not require user plane connectivity, and remains in an RRC Inactive Connected state, the last serving BS can continue its operation as a RAN anchor node, and there is no need to signal anything to the core network, as long as the UE current location is within an allowed tracking area. In certain embodiments, the 5G Cells may be grouped to form Tracking Areas on their provided radio network coverage area. The Tracking Areas can allow for UE tracking in the network with accuracy of at least one cell, or in some embodiments a few cells, while the UE is in Inactive Connected state. Intelligent control of t e serving BS relocation from the last serving BS to UE's current BS can help reduce frequency UE BS context transfers, and user plane path switching.

[0085] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearance of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language, throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0086] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. While some embodiments can be directed to a 5G environment, other embodiments can be directed to an LTE environment.

[0087] Partial Glossary

[0088] BS Base Station

[0089] loT Internet of Things

[0090] LTE Long Term Evolution

[0091 ] MSM Mobility and Session Manager

[0092] MME Mobility Management Entity

[0093] NB Node B

[0094] RAN Radio Access Network

[0095] RRC Radio Resource Control

[0096] TAU Tracking Area Update

[0097] UE User Equipment

[0098] uGW User Gateway

[0099] 5G-NB 5 ^th generation NodeB