Radio resource control resume wthout context fetch

According to certain embodiments, a target network node for communicating with a user equipment (UE) that was previously in communication with a source network node, comprises an interface operably coupled to processing circuitry. The interface is configured to receive a connection resume request from the user equipment, wherein the connection resume request comprises a resume identification associated with the source network node. The processing circuitry is configured to determine that the UE was previously in communication with the source network node. The interface is further configured to transmit the connection resume request to the source network node, receive a radio resource control (RRC) response from the source network node, and forward the RRC response to the UE.

TECHNICAL FIELD

The present disclosure relates, in general, to wireless communications and, more particularly, to wireless communications without relocating UE context information.

BACKGROUND

In the Third Generation Partnership Project (3GPP) study item “Next Generation New Radio (NR) Access Technology,” it is proposed that the Radio Resource Control (RRC) state model should be extended from 2 states (RRC_IDLE and RRC_CONNECTED) to 3 states (adding new state RRC_INACTIVE). A similar state model is also considered for Long Term Evolution (LTE) when LTE is connected to the Next Generation Core Network (also known as 5G-CN).

One aspect of the RRC_INACTIVE state is that the User Equipment (UE) and the Radio Access Network (RAN) store the Access Stratum (AS) context, and that the CN/RAN interface (called S1 in LTE/Evolved Packet Core (EPC) and NG-C in NR and LTE when connected to 5G-CN) is kept. This means that when a UE needs to reconnect to the network, it can resume an old connection, which can be much faster than setting up a new connection.

FIG. 1illustrates an example high-level, next generation network architecture. InFIG. 1, the RAN nodes LTE eNB and NR BS (also referred to as a gNB) are connected to the Next Generation CN (NG-CN or 5G-CN) using the NG-C control interface and NG-U user plane interface. The gNB is similar in functionality as the LTE eNB.

FIG. 2illustrates proposed state transitions for NR. The proposed procedures to transition between the states can be found in R2-1700535. In certain potential scenarios, even if the UE has stored the context in RRC_INACTIVE, the RAN can at any time discard the context and the CN/RAN connection when the UE is in RRC_INACTIVE. In case the RAN has discarded the context, the RAN will inform the UE about this when the UE sends an RRCConnectionResumeRequest message by responding with an RRCConnectionSetup message instead of an RRCConnectionResume message. In this case, the UE will also discard the context and continue to setup the RRC connection with the RRCConnectionSetupComplete message.

In scenarios where the AS context is stored and the CN/RAN connection is maintained, the CN is unaware that the UE is in RRC_INACTIVE and will consider the UE to be in ECM_CONNECTED (or the equivalent NR CN state). This means that the CN will not page the UE when incoming downlink (DL) packet(s) arrive, instead the CN will send the packets over NG-U to the RAN, and the RAN node will initiate paging (or notification) if needed.

RAN Based Notification Area

Another aspect of the RRC_INACTIVE state is the proposal of a RAN based notification area. A few of the 3GPP RAN2 assumptions concerning the RAN based notification area are:

1.RAN2 assumes that UE performs CN level location update whencrossing a TA boundary when in inactive (in addition to RANupdates based on RAN areas),2.There will be NG Core/CN Location Area code (similar to TrackingArea code) broadcast in system information of an NR Cell.1.RAN based notification area is UE-specific and configurable by thegNB via dedicated signalling2There will be a unique global Cell ID broadcast in system informationof NR Cell.1For the inactive state there will be a way to configure the UE witha RAN based notification area that is smaller than a TA.2A RAN notification area can cover a single cell or multiple cells

The RAN based notification area—the “RAN area”—allows the UE to move freely within the area without informing the network. When the UE wants to transmit data, it shall be able to resume its connection. Thus, even if the UE can freely move within the RAN area, it will still be tracked by the CN within the Tracking Areas (TA) since the UE is expected to perform TA updates to the CN due to mobility. To handle the RAN areas, the UE will also perform RAN area updates.

Suspend & Resume Procedures for the RRC_INACTIVE State

The proposed procedures for Suspend and Resume for the new RRC state RRC_INACTIVE are illustrated inFIGS. 3 and 4.

FIG. 3illustrates a proposed procedure for a successful RRC Connection Suspend. In the example ofFIG. 3, the UE is shown initially in RRC_CONNECTED state. User data is exchanged between the UE and the NR gNB. At step1, the NR gNB sends an RRC Connection Suspend message to the UE. The UE enters RRC_INACTIVE state.

FIG. 4illustrates a proposed procedure for a successful RRC Connection Resume. In the example ofFIG. 4, the UE is shown initially in RRC_INACTIVE state. The NR gNB sends a paging message to the UE. The UE performs Access Information acquisition. At step1, the UE sends a Physical Random Access Channel (PRACH) preamble to the NR gNB. At step2, the NR gNB sends a Random Access Response (RAR) to the UE. At step3, the UE sends an RRC Connection Resume Request message to the NR gNB. At step4, the NR gNB sends an RRC Connection Resume message to the UE. The UE enters RRC_CONNECTED state. At step5, the UE sends an RRC Connection Resume Complete message to the NR gNB. User data is exchanged between the UE and the NR gNB.

During both the RRC Connection Suspend and RRC Connection Resume procedures, the CN/RAN connection between the gNB and the Next Gen CN is kept (meaning no NR gNB-CN signaling is needed).

Notably, in the foregoing discussion, since the UE can move around within the RAN area while in RRC_INACTIVE without informing the network, if it resumes its connection in another gNB than the one where it was suspended, the target gNB has to fetch the UE context from the source gNB.

SUMMARY

To address the foregoing problems, disclosed is a method in a target network node for communicating with a user equipment (UE) that was previously in communication with a source network node. The method includes receiving a connection resume request from a UE, the connection resume request comprises a resume identification associated with the source network node; transmitting the connection resume request to the source network node; receiving a radio resource control (RRC) response from the source network node; and forwarding the RRC response to the UE.

Also disclosed is a target network node for communicating with a user equipment (UE) that was previously in communication with a source network node. The target network node includes an interface operably coupled to processing circuitry. The interface is configured to receive a connection resume request from the UE, wherein the connection resume request comprises a resume identification associated with the source network node. The processing circuitry is configured to determine that the UE (110) was previously in communication with the source network node. The interface is further configured to transmit the connection resume request to the source network node; receive a radio resource control (RRC) response from the source network node; and forward the RRC response to the UE.

In some embodiments, the target network node is a gNB and the source network node is a gNB.

In some embodiments, the connection resume request is an RRCConnectionResumeRequest. In some embodiments, the connection resume request comprises a security token. In some embodiments, the connection resume request is integrity protected using a security key used during the previous communications with the source network node. In some embodiments, small data received as part of or in conjunction with the connection resume request. In some embodiments, the connection resume request is transmitted to the source network node as part of or in conjunction with a retrieve UE context request.

In some embodiments, the RRC response is an RRCConnectionSuspend. In some embodiments, the RRC response comprises one or more of: a new resume identification associated with the source network node; a new security parameter; and a radio access network (RAN) area assignment.

In certain embodiments, the method further comprises, receiving via the interface, a UE context response from the source network node.

In certain embodiments, the method further comprises creating, via the processing circuitry, a local UE context; suspending the UE; and releasing the local UE context.

Also disclosed is a method in a source network node for facilitating communications between a user equipment (UE) and a target network node. The method includes receiving a connection resume request for the UE from the target network node, the connection resume request including a resume identification associated with the source network node. The method further includes verifying the connection resume request for the UE; generating a radio resource control (RRC) response for the UE; and transmitting the RRC response to the UE via the target network node.

Also disclosed is a source network node for facilitating communications between a user equipment (UE) and a target network node. The source network node comprises an interface operably coupled to processing circuitry. The interface is configured to receive a connection resume request for the UE from the target network node, the connection resume request including, a resume identification associated with the source network node. The processing circuitry is configured to verify the connection resume request for the UE and generate a radio resource control (RRC) response for the UE. The interface is further configured to transmit the RRC response to the UE via the target network node.

In some embodiments, the target network node is a gNB and the source network node is a gNB.

In some embodiments, the connection resume request is an RRCConnectionResumeRequest. In some embodiments, the connection resume request comprises a security token, in some embodiments, the connection resume request is integrity protected using a security key used during previous communications with the UE. In some embodiments, small data is received as part of or in conjunction with the connection resume request. In some embodiments, the connection resume request is transmitted to the source network node as part of or in conjunction with a retrieve UE context request.

In some embodiments, the RRC response is an RRCConnectionSuspend. In some embodiments, the RRC response comprises one or more of: a new resume identification associated with the source network node; a new security parameter; and a radio access network (RAN) area assignment.

In some embodiments, the method comprises receiving, via the interface, the connection resume request from the target network node as part of a retrieve user equipment (UE) context request. In some embodiments, the method comprises transmitting, via the interface, a UE context response to the target network node. In some embodiments, the method includes assigning, via the processing circuitry, a resume identification to the UE, the resume identification associated with the source network node.

Also disclosed is a method in a user equipment (UE) for communicating with a target network node. The method includes transmitting a connection resume request to the target network node, the connection resume request including a resume identification associated with an source network node previously communicating with the UE. The method further comprises receiving a radio resource control (RRC) response originating from the source network node and forwarded to the UE by the target network node.

Also disclosed is a user equipment (UE) for communicating with a target network node. The UE includes an interface operably coupled to processing circuitry. The processing circuitry is configured to operate in a RRC_INACTIVE state. The interface is configured to transmit a connection resume request to the target network node, the connection resume request including a resume identification associated with a source network node previously communicating with the UE; and receive a radio resource control (RRC) response originating from the source network node and forwarded to the UE by the target network node.

In some embodiments, the method further includes obtaining the resume identification associated with the source network node. In some embodiments, the target network node is a gNB and the source network node is a gNB.

In some embodiments, the RRC response is an RRCConnectionSuspend. In some embodiments, the connection resume request is an RRCConnectionResumeRequest. In some embodiments, the connection resume request comprises a security token. In some embodiments, the connection resume request is integrity protected using a security key used during previous communications with source network node. In some embodiments, small data is transmitted as part of or in conjunction with the connection resume request.

In some embodiments, the RRC response comprises one or more of: a new resume identification associated with the source network node; a new security parameter; and a radio access network (RAN) area assignment.

Certain embodiments of the present disclosure may provide one or more technical advantages. For example, in certain embodiment the network does not relocate the UE context when the UE resumes its connection. Since not all gNBs are connected with equally good backhaul (e.g., if deployed in a star-shaped layout), it may be advantageous to keep the UE context in the center of the star instead of relocating it to an edge if the UE only is active for a short time. In addition, relocation of the context to a target eNB/gNB would require both signaling with the RAN and between RAN and CN. Allowing a UE to request to resume its connection or perform a RAN/CN area update in a target gNB without relocating the UE context to the target gNB may reduce network congestion. Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

DETAILED DESCRIPTION

As described above, there are a number of technical issues involved in relocating user equipment (UE) context information to a new network node, particularly when the UE will only briefly be in a connected state with the new network node. For instance, if a UE is moving while in RRC_INACTIVE and resumes its connection in a different gNB, it may not be beneficial to always relocate the UE context to the target gNB. This is especially true if the UE quickly suspends its connection back to RRC_INACTIVE. One non-limiting example of such a scenario is when the UE is performing a RAN area or CN area registration update due to mobility. Another non-limiting example of such a scenario is when the UE is performing a periodic RAN area or CN area registration update (e.g., keep alive signalling). Still another non-limiting example of such a scenario is when the UE only has very little data to send/receive before it becomes inactive again. The problem can be particularly bad for fast moving UEs that are inactive, and would require frequent context relocations.

The present disclosure contemplates various embodiments that may address these and other deficiencies associated with existing approaches. In some cases, this is achieved by enabling a UE's RRC connection to be briefly resumed in a new gNB without relocating the UE context and still ensure security. Certain embodiments disclose a mechanism for how the UE can request to resume its connection (e.g., from RRC_INACTIVE to RRC_CONNECTED) or perform a RAN/CN area update in a target gNB when the UE context is located in another gNB, without relocating the UE context to the target gNB. In certain embodiments, instead of relocating the UE context to the target gNB, the gNB containing the UE context communicates with the UE through the target gNB. Certain embodiments also allow for pre-population of the UE context to several potential target eNB/gNBs to speed up the signaling transaction. In some cases, the pre-population can also be done without removing the context in the source eNB/gNB.

RRC Connection Resume

The baseline response for RRC resume is to relocate the UE context to the target node where the UE sent the RRCConnectionResumeRequest message (also known as message 3 or msg3). This is because, if the UE has been provided with a Next Hop Chaining Counter (NCC), it can calculate the necessary security keys in order to integrity protect msg3 and be able to receive encrypted msg4 (RRCConnectionResume, RRCConnectionSuspend, or RRCConnectionSetup depending on if the UE should resume a context, suspend to RRC_INACTIVE, or if the context cannot be resumed—rebuild the context).

FIG. 5illustrates an example RRC_INACTIVE to RRC_CONNECTED resume procedure. In particular,FIG. 5illustrates a successful resume procedure. In the example ofFIG. 5, the new gNB sends an RRC “suspend” (Resume ID, NCC) to the UE. The UE enters RRC_INACTIVE state. At step1, the UE sends a Random Access (RA) Preamble to the new gNB. At step2, the new gNB sends a RAR to the UE. At step3, the UE sends an RRCConnectionResumeRequest (Resume ID), Packet Data Convergence Protocol (PDCP) integrity protected to the new gNB. In some cases, data transmission occurs between the UE and the new gNB.

At step4, the new gNB sends a Retrieve UE Context Request message to the old gNB. At step5, the old gNB sends a Retrieve UE Context Response message to the new gNB. At step6, the new gNB sends a Path Switch Request to the AMF. At step7, the AMF and UPF modify bearers. At step8, the AMF sends a Path Switch Request Acknowledgement (ACK) to the new gNB. At step9, the new gNB sends an RRCConnectionResume message PDCP encrypted/integrity protected to the UE. The UE enters RRC_CONNECTED state. At step10, the UE sends an RRCConnectionResumeComplete PDCP encrypted/integrity protected to the new gNB.

In the example ofFIG. 5, calculating a new security key prior to message 3 (i.e., step3) makes it possible to relocate the UE context since the new gNB/eNB should not be allowed to obtain the old key used in the old gNB/eNB. Also of note, when the UE context is relocated, the CN/RAN connection will also be switched (S1 for legacy EPC or NG for NextGenCore).

RAN Area Updates

In certain scenarios, the network may know the UE location on a RAN area level which can, for example, be a list of cells, a list of CN Tracking Areas, or a newly defined RAN area index. This means that when the UE moves outside the RAN area, it needs to inform the network. A proposed method for this is shown inFIG. 6.

FIG. 6illustrates an RRC connection resume to perform a RAN area update. In the example ofFIG. 7, the UE is initially in RRC_INACTIVE state. The UE enters a new RAN area, and at step1sends a RA preamble to the new gNB. At step2, the new gNB sends a RAR message to the UE. At step3, the UE sends an RRCConnectionResumeRequest message (resumeID, causValue=“ranNotificationAreaUpdateRequest”) message to the new gNB.

At step4, the new gNB sends a Retrieve UE Context Request message to the old gNB. At step5, the old gNB sends a Retrieve UE Context Response message to the new gNB. At step6, the new gNB sends a Path Switch Request message to the AMF. At step7, the AMF and S-GW modify bearers. At step8, the AMF sends a Path Switch Request ACK message to the new gNB. At step9, the new gNB sends an RRCConnectionSuspend (ranAreaInformation, NCC) message to the UE. The UE enters RRC_INACTIVE state.

Tracking Area Update in RRC_INACTIVE

In certain scenarios a UE should perform a CN Tracking Area update even in RRC_INACTIVE when the UE enters a TA that it is not registered in. An example procedure of this is shown inFIG. 7.

FIG. 7illustrates an example CN Tracking Area update in RRC_INACTIVE. In the example ofFIG. 7, the UE is initially in RRC_INACTIVE state. The UE enters a new TA. At step1, the UE sends a RA preamble to the new gNB. At step2, the new gNB sends a RAR message to the UE. At step3, the UE sends an RRCConnectionResumeRequest message (resumeID, causValue=“mo-signal ling”) message to the new gNB. At step4, the new gNB sends a Retrieve UF. Context Request message to the old gNB. At step5, the old gNB sends a Retrieve UE Context Response message to the new gNB. At step6, the new gNB sends an RRCConnectionResume message to the UE. At step7, the UE sends an RRCConnectionResumeComplete message (dedicatedinfoNAS=“TAU Request”) to the new gNB. The UE enters RRC_CONNECTED state.

At step8, the new gNB sends a Path Switch Request message to the AMF. At step9, the AMF and S-GW modify bearers. At step10, the AMF sends a Path Switch Request ACK to the new gNB. At step11, the new gNB sends a TAU request to the AMF. The AMF performs Tracking Area update. At step12, the AMF sends a TAU Accept message to the UE. At step13, the new gNB sends a UE Context Release message to the old gNB. Upon or after an inactivity timer expires, the new gNB sends an RRCConnectionSuspend (ranAreaInformation, NCC) message to the UE. The UE enters RRC_INACTIVE.

There are several assumptions for RAN based notification, including:1. RAN2 assumes that UE performs CN level location update when crossing a TA boundary when in inactive (in addition to RAN updates based on RAN areas).2. There will be NG Core/CN Location Area code (similar to Tracking Area code) broadcast in system information of an NR Cell.3. In RAN2 the UE will perform RRC signalling in order to perform a CN update whenever it leaves its registered TA (as a consequence of the RRC signalling the RAN is aware of the UE's location)4. Support option 2 (cell list) and/or option 3 (RAN id) (FFS which one or both)
Periodic RAN Area Updates in RRC_INACTIVE

In addition, in certain scenarious the UE should perform periodic RAN area updates in RRC_INACTIVE, similar to what is done for periodic CN Tracking Area Updates in RRC_IDLE, in order for the network to be able to, for example, remove context of UEs which have been turned off if a UE fails to do these periodic updates (either once or multiple times, in LTE the default period for CN TAU is 54 minutes). As the UE should not do CN TAU in RRC_INACTIVE, it is necessary to do RAN area updates instead. If these fail, the RAN can inform the CN.

Since the UE only perform the periodic RAN area updates if it is still in its old RAN area (otherwise it would have done a mobility triggered RAN area update when it left the area), the UE could either resume the context in the old gNB or in a new gNB in the same area as shown inFIGS. 8 and 9below, respectively.

FIG. 8illustrates an example periodic RAN area update in the old gNB. In the example ofFIG. 8, the UE is initially in RRC_INACTIVE state. Upon or after a RAN area update timer expires, the UE at step1sends a RA Preamble to the gNB. At step2, the gNB sends a RAR to the UE. At step3, the UE sends an RRCConnectionResumeRequest message (resumeId, causeValue=“ranNotificationAreaUpdateRequest”) message to the gNB. At step4, the gNB sends an RRCConnectionSuspend message (ranAreaInformation, NCC) message to the UE. The UE enters RRC_INACTIVE state.

FIG. 9illustrates an example periodic update in the new gNB in an old RAN area. In the example ofFIG. 9, the UE is initially in RRC_INACTIVE state. Upon or after a RAN area timer expires, the UE at step1sends a RA Preamble to the new gNB. At step2, the new gNB sends a RAR message to the UE. At step3, the UE sends an RRCConnectionResumeRequest(resumeId, causeValue=“ranNotificationAreaUpdateRequest”) to the new gNB. At step4, the new gNB sends a Retrieve UE Context Request message to the old gNB. At step5, the old gNB sends a Retrieve UE Context Response message to the new gNB. At step6, the new gNB sends a Path Switch Request message to the AMF. At step7, the AMF and S-GW modify bearers. At step8, the AMF sends a Path Switch Request ACK to the new gNB. At step9, the new gNB sends a UE context release message to the old gNB. At step10, the new gNB sends an RRCConnectionSuspend(ranAreaInformation, NCC) message to the UE. The UE enters RRC_INACTIVE state.

In the example ofFIG. 8described above, the UE context doesn't have to be relocated since the UE resumes the connection in the old gNB, while in the example ofFIG. 9, the UE context is relocated.

Example Configurations

FIGS. 10 and 11illustrate two example deployments where there are technical benefits to not relocating the UE context when the UE resumes its connection.FIG. 10illustrates an example heterogeneous network deployment, in accordance with certain embodiments. More particularly,FIG. 10illustrates a heterogeneous network deployment with one macro cell and 12 pico cells. In the example ofFIG. 10, the RAN area consists of one macro gNB (with large coverage range) and 12 pico gNBs (with much smaller coverage range). If a UE was connected to the Macro base station when it suspended its connection, and then moves while in RRC_INACTIVE so that it enters the coverage of a pico cell, when the UE resumes its connection it will do so towards the pico cell. If the UE has little or no data (e.g., only performs a RAN area update), in the baseline solution, the network would relocate the UE context to the pico cell and then quickly suspend the UE to RRC_INACTIVE, if the UE moves again when in RRC_INACTIVE, it may enter another pico cell. When it then resumes its connection, the network will need to fetch the context from the old pico cell to the new pico cell.

As described in greater detail below, in certain embodiments, the UE context may be kept in the macro gNB. When the UE resumes the connection in pico cell1, and then suspends, the context is still in the Macro gNB. When the UE then resumes the connection in pico cell2, the context will still be the same. In some embodiments, one option is to duplicate/pre-allocate the UE context. For example, when the UE suspends its connection, the UE context is also stored in the gNB most likely to be resumed in (e.g., all nodes in the RAN area). Alternatively, the UE context could be stored in the gNB the UE suspended in plus the Macro gNB.

FIG. 11illustrates an example star-shaped deployment, in accordance with certain embodiments. More particularly,FIG. 11illustrates an example deployment with nine gNBs in the same RAN area, where relocation of the UE context may not be optimal. The star-shaped deployment ofFIG. 11includes a gNB in the center of the star, connected to eight gNBs located at the arms of the star where all gNBs are included in the RAN area. The other gNBs have no direct connection between them, but are connected through the central gNB. If the UE has its UE context stored in the central gNB when it is in RRC_INACTIVE, and then moves to one of the outer gNB and performs the RRC connection resume, if the UE context is fetched to this gNB and the UE suspends back to RRC_INACTIVE, and then moves to another gNB the UE context would have to be relocated again. In certain embodiments, the UE context is stored in the central gNB and the UE resumes its context in any of the outer gNBs, so that the context would not have to be relocated.

FIGS. 10 and 11are merely illustrative of example deployments that may benefit from embodiments of the present disclosure. The various embodiments described by are especially advantageous for scenarios where the UE has very little data to send, or only sends, for example, RAN area updates. In some cases, if the UE has a large amount of data to transmit, the UE context may still be relocated.FIGS. 12-20provide additional explanation of embodiments of the present disclosure.

Exemplary Network

FIG. 12is a block diagram illustrating an embodiment of a network100, in accordance with certain embodiments. Network100includes one or more UE(s)110(which may be interchangeably referred to as wireless devices110) and one or more network node(s)115(which may be interchangeably referred to as NR gNBs115or eNBs). In certain embodiments, network nodes115may be differentiated as network nodes115a,115b,115c. . .115n. UEs110may communicate with network nodes115over a wireless interface. For example, a UE110may transmit wireless signals to one or more of network nodes115, and/or receive wireless signals from one or more of network nodes115. The wireless signals may contain voice traffic, data traffic, control signals, and/or any other suitable information. In some embodiments, an area of wireless signal coverage associated with a network node115may be referred to as a cell125. In some embodiments, UEs110may have device-to-device (D2D) capability. Thus, UEs110may be able to receive signals from and/or transmit signals directly to another UE.

In certain embodiments, network nodes115may interface with a radio network controller. The radio network controller may control network nodes115and may provide certain radio resource management functions, mobility management functions, and/or other suitable functions. In certain embodiments, the functions of the radio network controller may be included in network node115. The radio network controller may interface with a core network node. In certain embodiments, the radio network controller may interface with the core network node via an interconnecting network120. Interconnecting network120may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, or any combination of the preceding. Interconnecting network120may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.

In some embodiments, the core network node may manage the establishment of communication sessions and various other functionalities for UEs110. UEs110may exchange certain signals with the core network node using the non-access stratum layer. In non-access stratum signaling, signals between UEs110and the core network node may be transparently passed through the radio access network. In certain embodiments, network nodes115may interface with one or more network nodes over an internode interface, such as, for example, an X2 interface.

As described above, example embodiments of network100may include one or more wireless devices110, and one or more different types of network nodes capable of communicating (directly or indirectly) with wireless devices110.

In some embodiments, the non-limiting term UE is used. UEs110described herein can be any type of wireless device capable of communicating with network nodes115or another UE over radio signals. UE110may also be a radio communication device, target device, D2D UE, machine-type-communication UE or UE capable of machine to machine communication (M2M), low-cost and/or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), etc. UE110may operate under either normal coverage or enhanced coverage with respect to its serving cell. The enhanced coverage may be interchangeably referred to as extended coverage. UE110may also operate in a plurality of coverage levels (e.g., normal coverage, enhanced coverage level1, enhanced coverage level2enhanced coverage level3and so on). In some cases, UE110may also operate in out-of-coverage scenarios.

Also, in some embodiments generic terminology, “radio network node” (or simply “network node”) is used, it can be any kind of network node, which may comprise a base station (BS), radio base station, Node B, multi-standard radio (MSR) radio node such as MSR BS, evolved Node B (eNB), NR gNB, network controller, radio network controller (RNC), base station controller (BSC), relay node, relay donor node controlling relay, base transceiver station (BTS), access point (AP), radio access point, transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), Multi-cell/multicast Coordination Entity (MCE), core network node (e.g., MSC, MME, etc.), O&M, OSS, SON, positioning node (e.g., E-SMLC), MDT, or any other suitable network node.

The terminology such as network node and UE should be considered non-limiting and does in particular not imply a certain hierarchical relation between the two; in general “gNodeB” could be considered as device1and “UE” device2, and these two devices communicate with each other over some radio channel.

Example embodiments of UE110, network nodes115, and other network nodes (such as radio network controller or core network node) are described in more detail below with respect toFIGS. 13-20.

AlthoughFIG. 12illustrates a particular arrangement of network100, the present disclosure contemplates that the various embodiments described herein may be applied to a variety of networks having any suitable configuration. For example, network100may include any suitable number of UEs110and network nodes115, as well as any additional elements suitable to support communication between UEs or between a UE and another communication device (such as a landline telephone). Furthermore, although certain embodiments may be described as implemented in a Long Term Evolution (LTE) network, the embodiments may be implemented in any appropriate type of telecommunication system supporting any suitable communication standards (including 5G, NR standards) and using any suitable components, and are applicable to any radio access technology (RAT) or multi-RAT systems in which a UE receives and/or transmits signals (e.g., data). For example, the various embodiments described herein may be applicable to Next Generation New Radio (NR) Access Technology, LTE, LTE-Advanced, 5G, UMTS, HSPA, GSM, cdma2000, WCDMA, WiMax, UMB, WiFi, another suitable radio access technology, or any suitable combination of one or more radio access technologies. Although certain embodiments may be described in the context of wireless transmissions in the downlink, the present disclosure contemplates that the various embodiments are equally applicable in the uplink.

Network Node Communication Without Relocating UE Context

FIGS. 13-15describe example embodiments wherein a UE110may communicate with a new (e.g., target) gNB without relocating the UE110context from an old (e.g., source) gNB, while still ensuring security.

FIG. 13illustrates an example RRCConnectionResume due to periodic RAN area update in a new gNB without context relocation, in accordance with certain embodiments. More particularly,FIG. 13shows a signaling diagram for the case of a periodic RAN area update in a new gNB within the old RAN area. In the example ofFIG. 13, the UE110is initially in RRC_INACTIVE stale. Upon or after a RAN area update timer expires, the UE110at step1sends a RA preamble to a new gNB. At step2, the new gNB sends a RAR message to the UE110. At step3, the UE110sends an RRCConnectionResume Request message (resumeId, causeValue=“ranNotificationAreaUpdateRequest”) to the new gNB. In certain embodiments, when the new gNB receives the RRCConnectionResumeRequest message, it sends the RRCConnectionResume Request directly to the old gNB (step3). The new gNB may route the message to the old gNB based on the resumeID that the UE110provided in the RRCConnectionResume Request message.

According to one example embodiment, the RRCConnectionResumeRequest message includes a security token (e.g., Short-MAC-I) calculated using an old security key (e.g., used by the UE110in the old cell) as well as other parameters such as a target cell ID/frequency band. The old gNB may verify the security token to ensure the message is from the right UE110.

According to another example embodiment, the RRCConnectionResumeRequest may be integrity protected using the old security key (e.g., using PDCP integrity protection (PDCP Medium Access Control (MAC)). The old gNB verifies the integrity of the message.

According to another example embodiment, the RRCConnectionResume Request is integrity protected using a new security key (e.g., using PDCP integrity protection (PDCP MAC)). The new security key may be derived by the UE110in the new cell (e.g., based on the old key, plus additional parameters). The old gNB may also derive the new key and use this to verify the integrity of the message.

At this stage the old gNB has verified that it is the right UE110sending the resume request. As a result of this, at step4the old gNB will generate an RRC response message (e.g., RRCConnectionSuspend) which may be integrity protected and/or ciphered using the old or new key. The message will be transparently forwarded to the UE110via the new gNB (step4). The message may also include assignment of a new resumeID (still pointing to the old gNB) and additional parameters such as, new security parameter (e.g., NCC) or RAN area assignment.

FIG. 14illustrates an example of small data transmission in RRC_INACTIVE without UE110context relocation, in accordance with certain embodiments. In the example ofFIG. 14, the UE110is initially in RRC_INACTIVE state. Small data may refer to the communication of small data payloads (e.g., machine type communication (MTC) data) in network100or any other suitable data. Small uplink (UL) data arrives at the UE110. At step1, the UE110sends a RA preamble to the new gNB. At step2, the new gNB sends a RAR message to the UE110.

At step3, the UE110sends an RRCConnectionResumeRequest (resumeId, causeValue=“smallData”, UIData) to the new gNB. In the example ofFIG. 14, the UE110triggers the resumption by transmission of small data and may include some small data in Msg.3 or in conjunction with Msg.3, such as in subsequent transmissions after message 3. When the new gNB receives the RRCConnectionResumeRequest, it sends the RRCConnectionResumeRequest (including all parameters and the UL data) directly to the old gNB (at step4) as part of a Retrieve UE context request or other message. The new gNB will route the message to the old gNB based on the resumeID that the UE110provided in the RRCConnectionResumeRequest.

According to one example embodiment, the RRCConnectionResumeRequest contains a security token (e.g., Short-MAC-I) calculated using the old security key (used by the UE110in the old cell) as well as other parameters such as a target cell ID/frequency band. The old gNB verifies the security token, to ensure the message is from the right UE110.

According to another example embodiment, the RRCConnectionResumeRequest is integrity protected using the old security key (e.g., using PDCP integrity protection (PDCP MAC)). The old gNB verifies the integrity of the message.

According to another example embodiment, the RRCConnectionResumeRequest is integrity protected using a new security key (e.g., using PDCP integrity protection (PDCP MAC)). The new security key may be derived by the UE110in the new cell (e.g., based on the old key, plus additional parameters). The old gNB also derives the new key and uses this to verify the integrity of the message.

At this stage the old gNB has verified that it is the right UE110sending the resume request. As a result of this, the old gNB will forward the UE context to the new gNB and optionally include an UL Data ACK. (step5). Additionally the old gNB may forward the UL data to the (5G) Core Network. The UE context sent to the new gNB can contain information such as the new UE security key and/or the new UE Resume ID to be assigned to the UE110. The old gNB will also store the context. Once the new gNB receives the context, it can generate an RRC message (e.g., RRCConnectionSuspend) which can be sent to the UE110with the optional UL data ACK; The RRC message can be encrypted and/or integrity protected using PDCP protocol. The RRC message may contain a new resume ID, new security parameter (e.g., NCC), and/or RAN area assignment. After the new gNB has sent the information to the UE110(and possibly received acknowledgement from the UE110), the new gNB can delete the UE context locally.

In the example embodiments described above, thanks to the possibility to assign the UE110a Resume ID which is “pointing” to the old gNB it is possible to keep the context in the old gNB, since ail subsequent signaling or data will be routed to the old gNB. This minimizes signaling, thereby reducing network congestion.

Additionally, the embodiment makes it possible to change the security keys for UE transactions. This has several benefits. For example, using new keys for every transaction may advantageously avoid the need to maintain PDCP sequence number when UE110is in RRC_INACTIVE, since all PDCP SNs can be set to 0 for a new key. If old key is used then SNs need to be maintained to protect against replay protection. As another example, using new keys makes it possible to relocate the context when desirable (network choice) since this can be done without giving access to the old keys to the new node (which should be avoided for security reasons). As another example, using new keys makes it possible to pre-populate the UE context in several RAN nodes to speed up signalling, since old keys does not need to be exposed.

FIG. 15illustrates an example state transition from RRC_INACTIVE to RRC_CONNECTED without context relocation for small data transmission, in accordance with certain embodiments, in the example ofFIG. 15, the UE110is initially in RRC_INACTIVE state. Small UL data arrives. At step1, the UE110sends a RA preamble to the new gNB. At step2, the new gNB sends a RAR message to the UE110. At step3, the UE110sends an RRCConnectionResumeRequest (resumeId, cause Value=“smallData”) to the new gNB.

In the example ofFIG. 15, the UE110resumes its connection in a new gNB with a causeValue flag of “smallData.” Alternatively, the causeValue flag could be “mo-signalling” to indicate that the UE110does a Tracking Area Update.

When the new gNB receives the RRCConnectionResumeRequest with the “small data” indication, at step4it sends a “Retrieve UE context request” message to the old gNB (located using the resumeId), and includes the “small data” indicator. In some embodiments the small data indication may be sent in conjunction with the Connection Resume Request. For illustrative purposes, two alternatives to the response of this message are disclosed. According to a first example embodiment, the old gNB responds with a “retrieve UE context response” with the UE context including the parameters needed to suspend the UE110(resumeId, RanAreaInformation, NCC). According to a second example embodiment, the old gNB responds with a “Retrieve UE context response” with only the UE context.

In both the first and second example embodiments above, the new gNB creates a local copy of UE context and sends an RRCConnectionResume message to the UE110at step6. The RRCConnectionResume message transitions the UE110to RRC_CONNECTED state.

At step7, the UE110responds with a RRCConnectionResumeComplete, which may include UL data, which is then forwarded to the old gNB at step8. Depending on configurations, the UE110may send a few subsequent data transmissions which are all forwarded to the old gNB. This is shown at step9in the example ofFIG. 15.

When the UE110is finished with the “small data” transmission, it can indicate this in a variety of ways. As one example, the UE110can indicate this by a buffer status report, either sent before the first transmission, in between data, or after the last message indicating to the network how much data the UE110wants to send. As another example, the UE110can indicate this by an end of data marker indicating that the UE110has finished with the “small data” transmission. As still another example, the UE110can indicate this by a preconfigured size of the “small data”—if the standardization determines that “small data” only equals to a fixed number of maximum UL transmissions.

When the UE110has completed the UL traffic, the new gNB can decide to suspend the UE110. This is shown in the example ofFIG. 15at step11. In the first example embodiment above, where the new gNB received the configurations for the new ran Area and new resumeId, the new gNB indicates to the old gNB that the small data transmission is finished. In the second example embodiment above, the old gNB responds to this message with a UE suspend response including this information, shown in the example ofFIG. 15at step13. After that, at step14the new gNB suspends the UE110with a resumeId pointing to the old gNB. As a last step, the new gNB deletes the UE context at step15and the UE context is stored in the old gNB. The UE110enters RRC_INACTIVE state.

In certain embodiments, different steps in the various embodiments described above can be combined to create new embodiments. In addition, the various embodiments described above can be enhanced with the following novel UE functionality. In certain embodiments, the UE110may indicate to the network (e.g., in the RRCConnectionResumeRequest) if the procedure should be executed without performing context fetch. This information may have been provided to the UE110in the RRCConnectionSuspend message (or other message). This will allow the new gNB to know which procedure to apply, which may advantageously lead to more efficient handling.

In certain embodiments, the UE110may indicate a counter or validity information related to UE context. This may allow the new gNB to determine if a local context of the UE110is still valid, which may advantageously lead to more efficient handling (no context fetch). The local context of the UE110could be a context used in previous access, or a pre-populated context. The UE110could either calculate an maintain counter or validity information or the information can be provided to the UE110in RRCConnectionSuspend.

In certain embodiments, the UE110could indicate how much data it has in its buffer, which may advantageously enable the new gNB or the old gNB to decide if the UE context, should be relocated or not. Small amounts of data may be best served by keeping the context, while if a lot of data will be send it could be better to relocate to optimized data forwarding path in the network.

In certain embodiments, the UE110can derive different security keys depending on which node the UE110is connected to (or which cell). This may advantageously ensure different keys are generated for different nodes, which increases the security of the system.

Descriptions of Exemplary Network Components

FIG. 16is a block schematic of an exemplary wireless device110, in accordance with certain embodiments. Wireless device110may refer to any type of wireless device communicating with a node and/or with another wireless device in a cellular or mobile communication system. Examples of wireless device110include a mobile phone, a smart phone, a PDA (Personal Digital Assistant), a portable computer (e.g., laptop, tablet), a sensor, an actuator, a modem, a machine-type-communication (MTC) device/machine-to-machine (M2M) device, laptop embedded equipment (LEE), laptop mounted equipment (LME), USB dongles, a D2D capable device, or another device that can provide wireless communication. A wireless device110may also be referred to as UE110, a station (STA), a device, or a terminal in some embodiments. Wireless device110includes transceiver1610, processing circuitry1620, and memory1630. In some embodiments, transceiver1610facilitates transmitting wireless signals to and receiving wireless signals from network node115(e.g., via an antenna), processing circuitry1620executes instructions to provide some or all of the functionality described above as being provided by wireless device110, and memory1630stores the instructions executed by processing circuitry1620.

Processing circuitry1620may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of wireless device110, such as the functions of wireless device110described above in relation toFIGS. 1-15. In some embodiments, processing circuitry1620may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and/or other logic.

Other embodiments of wireless device110may include additional components beyond those shown inFIG. 16that may be responsible for providing certain aspects of the wireless device's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solution described above). As just one example, wireless device110may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processing circuitry1620. Input devices include mechanisms for entry of data into wireless device110. For example, input devices may include input mechanisms, such as a microphone, input elements, a display, etc. Output devices may include mechanisms for outputting data in audio, video and/or hard copy format. For example, output devices may include a speaker, a display, etc.

FIG. 17is a block schematic of an exemplary network node115, in accordance with certain embodiments. Network node115may be any type of radio network node or any network node that communicates with a UE and/or with another network node. Examples of network node115include an eNodeB, gNB, a node B, a base station, a wireless access point (e.g., a Wi-Fi access point), a low power node, a base transceiver station (BTS), relay, donor node controlling relay, transmission points, transmission nodes, remote RF unit (RRU), remote radio head (RRH), multi-standard radio (MSR) radio node such as MSR BS, nodes in distributed antenna system (DAS), O&M, OSS, SON, positioning node (e.g., E-SMLC), MDT, or any other suitable network node. Network nodes115may be deployed throughout network100as a homogenous deployment, heterogeneous deployment, or mixed deployment. A homogeneous deployment may generally describe a deployment made up of the same (or similar) type of network nodes115and/or similar coverage and cell sizes and inter-site distances. A heterogeneous deployment may generally describe deployments using a variety of types of network nodes115having different cell sizes, transmit powers, capacities, and inter-site distances. For example, a heterogeneous deployment may include a plurality of low-power nodes placed throughout a macro-cell layout. Mixed deployments may include a mix of homogenous portions and heterogeneous portions.

Network node115may include one or more of transceiver1710, processing circuitry1720, memory1730, and network interface1740. In some embodiments, transceiver1710facilitates transmitting wireless signals to and receiving wireless signals from wireless device110(e.g., via antenna1750), processing circuitry1720executes instructions to provide some or all of the functionality described above as being provided by a network node115, memory1730stores the instructions executed by processing circuitry1720, and network interface1740communicates signals to backend network components, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), core network nodes or radio network controllers130, etc.

Processing circuitry1720may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of die described functions of network node115, such as those described above in relation toFIGS. 1-15. In some embodiments, processing circuitry1720may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, and/or other logic.

In some embodiments, network interface1740is communicatively coupled to processing circuitry1720and may refer to any suitable device operable to receive input for network node115, send output from network node115, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. Network interface1740may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

FIG. 18is a block schematic of an exemplary radio network controller or core network node130, in accordance with certain embodiments. Examples of network nodes can include a mobile switching center (MSC), a serving GPRS support node (SGSN), a mobility management entity (MME), a radio network controller (RNC), a base station controller (BSC), and so on. The radio network controller or core network node130includes processing circuitry1820, memory1830, and network interface1840. In some embodiments, processing circuitry1820executes instructions to provide some or ail of the functionality described above as being provided by the network node, memory1830stores the instructions executed by processing circuitry1820, and network interface1840communicates signals to any suitable node, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), network nodes115, radio network controllers or core network nodes130, etc.

Processing circuitry1820may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or ail of the described functions of the radio network controller or core network node130. In some embodiments, processing circuitry1820may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, and/or other logic.

In some embodiments, network interface1840is communicatively coupled to processing circuitry1820and may refer to any suitable device operable to receive input for the network node, send output from the network node, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding. Network interface1840may include appropriate hardware (e.g., port, modern, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.

Other embodiments of the network node may include additional components beyond those shown inFIG. 18that may be responsible for providing certain aspects of the network node's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solution described above).

FIG. 19is a schematic block diagram of an exemplary wireless device, in accordance with certain embodiments. Wireless device110may include one or more modules. For example, wireless device110may include a determining module1910, a communication module1920, a receiving module1930, an input module1940, a display module1950, and any other suitable modules. In some embodiments, one or more of determining module1910, communication module1920, receiving module1930, input module1940, display module1950, or any other suitable module may be implemented using one or more processors, such as processing circuitry1620described above in relation toFIG. 16. In certain embodiments, the functions of two or more of the various modules may be combined into a single module. Wireless device110may perform the methods for RRC resume without context fetch described above with respect toFIGS. 1-15.

Determining module1910may perform the processing functions of wireless device110. Determining module1910may include or be included in one or more processors, such as processing circuitry1620described above in relation toFIG. 16. Determining module1910may include analog and/or digital circuitry configured to perform any of the functions of determining module1910and/or processing circuitry1620described above. The functions of determining module1910described above may, in certain embodiments, be performed in one or more distinct modules.

Communication module1920may perform the transmission functions of wireless device110. As one example, communication module1930may send a connection resume request to a first network node (e.g., a new network node), the connection resume request including a resume identification associated with a second network node (e.g., an old network node). Communication module1920may include a transmitter and/or a transceiver, such as transceiver1610described above in relation toFIG. 16. Communication module1920may include circuitry configured to wirelessly transmit messages and/or signals. In particular embodiments, communication module1920may receive messages and/or signals for transmission from determining module1910. In certain embodiments, the functions of communication module1920described above may be performed in one or more distinct modules.

Receiving module1930may perform the receiving functions of wireless device110. For example, receiving module1930may receive an RRC response message from the second network node that is transparently forwarded to the wireless device by the first network node. As another example, receiving module1930may obtain the resume identification associated with the second network node.

Receiving module1930may include a receiver and/or a transceiver. Receiving module1930may include a receiver and/or a transceiver, such as transceiver1610described above in relation toFIG. 16. Receiving module1930may include circuitry configured to wirelessly receive messages and/or signals. In particular embodiments, receiving module1930may communicate received messages and/or signals to determining module1910. The functions of receiving module1930described above may, in certain embodiments, be performed in one or more distinct modules.

Input module1940may receive user input intended for wireless device110. For example, the input module may receive key presses, button presses, touches, swipes, audio signals, video signals, and/or any other appropriate signals. The input module may include one or more keys, buttons, levers, switches, touchscreens, microphones, and/or cameras. The input module may communicate received signals to determining module1910. The functions of input module1940described above may, in certain embodiments, be performed in one or more distinct modules.

Display module1950may present signals on a display of wireless device110. Display module1950may include the display and/or any appropriate circuitry and hardware configured to present signals on the display. Display module1950may receive signals to present on the display from determining module1910. The functions of display module1950described above may, in certain embodiments, be performed in one or more distinct modules.

FIG. 20is a schematic block diagram of an exemplary network node115, in accordance with certain embodiments. Network node115may include one or more modules. For example, network node115may include determining module2010, communication module2020, receiving module2030, and any other suitable modules. In some embodiments, one or more of determining module2010, communication module2020, receiving module2030, or any other suitable module may be implemented using one or more processors, such as processing circuitry1720described above in relation toFIG. 17. In certain embodiments, the functions of two or more of the various modules may be combined into a single module. Network node115may perform the methods for RRC resume without context fetch described above with respect toFIGS. 1-35.

Determining module2010may perform the processing functions of network node115. In certain embodiments, network node115may perform the functions of the first network node (or new gNB) described herein. In such a scenario, determining module2010may create a local UE context and releasing the local UE context after suspending the wireless device. In certain embodiments, network node115may perform the functions of the second network node (or old gNB) described herein. In such a scenario, determining module2010verify the connection resume request. As another example, determining module2010may generate an RRC response message for the wireless device. As still another example, determining module2010may assign a resume identification to the wireless device, the resume identification associated with the second network node.

Determining module2010may include or be included in one or more processors, such as processing circuitry1720described above in relation toFIG. 17. Determining module2010may include analog and/or digital circuitry configured to perform any of the functions of determining module2010and/or processing circuitry1720described above. The functions of determining module2010may, in certain embodiments, be performed in one or more distinct modules.

Communication module2020may perform the transmission functions of network node115. In certain embodiments, network node115may perform the functions of the first network node (or new gNB) described herein. In such a scenario, communication module2020may send the connection resume request to the second network node associated with the resume identification based on the resume identification included in the connection resume request. As another example, communication module2020may forward an RRC response message from the second network node to the wireless device. As still another example, communication module2020may send the connection resume request to the second network node as part of a Retrieve UE Context request or other message. In some embodiments, communication module2020may send the connection resume request to the second network node in conjunction with a Retrieve UE Context request or other message.

In certain embodiments, network node115may perform the functions of the second network node (or old gNB). In such a scenario, communication module2020may send the RRC response message to the wireless device via the first network node. As another example, communication module2020may send a UE context response to the first network node.

Communication module2020may transmit messages to one or more of wireless devices110. Communication module2020may include a transmitter and/or a transceiver, such as transceiver1710described above in relation toFIG. 17. Communication module2020may include circuitry configured to wirelessly transmit messages and/or signals. In particular embodiments, communication module2020may receive messages and/or signals for transmission from determining module2010or any other module. The functions of communication module2020may, in certain embodiments, be performed in one or more distinct modules.

Receiving module2030may perform the receiving functions of network node115. In certain embodiments, network node115may perform the functions of the first net work node (or new gNB) described herein. In such a scenario, receiving module2030may receive a connection resume request from a wireless device, the connection resume request including a resume identification associated with a second network node. As another example, receiving module2030may receive a UE context response from the second network node.

In certain embodiments, network node115may perform the functions of the second network node (or old gNB). In such a scenario, receiving module2030may receive a connection resume request for a wireless device from a first network node, the connection resume request including a resume identification associated with the second network node. As another example, receiving module2030may receive the connection resume request from the first network node as part of a Retrieve UE Context request or other message. In some embodiments, receiving module2030may receive the connection resume request from tire first network node in conjunction with a Retrieve UE Context request or other message.

Receiving module2030may receive any suitable information from a wireless device. Receiving module2030may include a receiver and/or a transceiver, such as transceiver1710described above in relation toFIG. 17. Receiving module2030may include circuitry configured to wirelessly receive messages and/or signals. In particular embodiments, receiving module2030may communicate received messages and/or signals to determining module2010or any other suitable module. The functions of receiving module2030may, in certain embodiments, be performed in one or more distinct modules.

Determining module2010, communication module2020, and receiving module2030may include any suitable configuration of hardware and/or software. Network node115may include additional modules beyond those shown inFIG. 20that may be responsible for providing any suitable functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the various solutions described herein).

Abbreviations used in the Preceding Description Include: