Patent Description:
To communicate wirelessly with a network, a user equipment (UE) may establish a connection to the network using a base station (e.g., a serving cell) that supports a Fifth-Generation core network (5GC), an Evolved Packet Core (EPC), or both. After suspending the connection to the network, the UE may perform a cell-selection procedure that selects a different base station. If the selected base station supports a different core-network type than the previous base station, however, an attempt to resume the connection to the network using the selected base station may fail.

<CIT> describes a user equipment (UE) that provides an indication of a selected connection mode, LTE or eLTE, to a network and facilitates a connection of the UE to a Core Network based at least in part on the indication of the selected connection mode.

<NPL> provides a disclosure related to wireless systems.

In accordance with the invention, there is provided: a method performed by a user equipment as recited by claim <NUM>; a user equipment as recited by claim <NUM>; and a computer readable storage medium as recited by claim <NUM>.

Apparatuses of and techniques for handling an attempt to resume a wireless connection using a base station that supports a different core-network type are described with reference to the following drawings. The same numbers are used throughout the drawings to reference like features and components:.

This document describes techniques and devices for handling an attempt to resume a wireless connection using a base station that supports a different core-network type. While in a current resource control state, such as an inactive state, a user equipment (UE) can select a base station that supports a different core-network type than a previous base station. In some cases, this selected base station may not support the current resource control state or may not enable the UE to transition to a different resource control state, such as a connected state. Consequently, if the UE attempts to perform a procedure to transition the UE to a different resource control state, the procedure may fail. The failure may result in wasted network resources or delayed communications with the UE.

These techniques and devices enable handling an attempt to resume a wireless connection using a base station that supports a different core-network type. In particular, a resource control module of a UE determines whether or not a core-network type supported by a currently selected base station differs from a core-network type supported by a previously-selected base station before performing a connection-resume procedure. If the core-network types differ, the resource control module performs another action instead of performing the connection-resume procedure. As an example action, the resource control module releases the wireless connection to the network, performs a connection-establishment procedure with the second base station, postpones the connection-resume procedure, or sends a message to an upper layer. In this way, the resource control module takes steps to proactively avoid performing a connection-resume procedure that may fail due to differences in core-network types.

<FIG> illustrates an example environment <NUM>, in which handling an attempt to resume a wireless connection using a base station that supports a different core-network type can be implemented. The environment <NUM> includes multiple UEs <NUM>, illustrated as UE <NUM>, UE <NUM>, and UE <NUM>. Each UE <NUM> communicates with one or more base stations <NUM> (illustrated as base stations <NUM>, <NUM>, <NUM>, and <NUM>) through one or more wireless communication links <NUM> (wireless link <NUM>), illustrated as wireless links <NUM> and <NUM>. Although illustrated as a smartphone, the UE <NUM> can be implemented as any suitable computing or electronic device, such as a mobile communication device, a modem, a cellular phone, a gaming device, a navigation device, a media device, a laptop computer, a desktop computer, a tablet computer, a smart appliance, a vehicle-based communication system, and the like. The base station <NUM> (e.g., an Evolved Universal Terrestrial Radio Access Network Node B, E-UTRAN Node B, evolved Node B, eNodeB, eNB, Next Generation Evolved Node B, ng-eNB, Next Generation Node B, gNode B, gNB, or the like) can be implemented in a macrocell, microcell, small cell, picocell, or the like, or any combination thereof.

The base stations <NUM> communicate with the UE <NUM> using the wireless links <NUM> and <NUM>, which may be implemented as any suitable type of wireless link. The wireless link <NUM> and <NUM> can include a downlink of data and control information communicated from the base stations <NUM> to the UE <NUM>, an uplink of other data and control information communicated from the UE <NUM> to the base stations <NUM>, or both. The wireless links <NUM> include one or more wireless links or bearers implemented using any suitable communication protocol or standard, or combination of communication protocols or standards such as 3rd Generation Partnership Project Long-Term Evolution (3GPP LTE), Enhanced Long-Term Evolution (eLTE), Fifth-Generation New Radio (<NUM> NR), Fourth-Generation (<NUM>) standard, and so forth. Multiple wireless links <NUM> can be aggregated in a carrier aggregation to provide a higher data rate for the UE <NUM>. Multiple wireless links <NUM> from multiple base stations <NUM> can be configured for Coordinated Multipoint (CoMP) communication with the UE <NUM>.

The base stations <NUM> are collectively a Radio Access Network <NUM> (RAN, Evolved Universal Terrestrial Radio Access Network, E-UTRAN, <NUM> NR RAN or NR RAN) that each use a Radio Access Technology (RAT). The RANs <NUM> include an NR RAN <NUM> and an E-UTRAN <NUM>. In <FIG>, core networks <NUM> include a Fifth-Generation Core (5GC) network <NUM> (5GC <NUM>) and an Evolved Packet Core (EPC) network <NUM> (EPC <NUM>), which are different types of core networks. The base stations <NUM> and <NUM> in the NR RAN <NUM> are connected to the 5GC <NUM>. The base stations <NUM> and <NUM> in the E-UTRAN <NUM> connect to the EPC <NUM>. Optionally or additionally, the base station <NUM> connects to both the 5GC <NUM> and EPC <NUM>.

The base stations <NUM> and <NUM> connect, at <NUM> and <NUM> respectively, to the 5GC <NUM> using an NG2 interface for control-plane signaling and using an NG3 interface for user-plane data communications. The base stations <NUM> and <NUM> connect, at <NUM> and <NUM> respectively, to the EPC <NUM> using an S1 interface for control-plane signaling and user-plane data communications. If the base station <NUM> connects to both the 5GC <NUM> and EPC <NUM>, the base station <NUM> can connect to the 5GC <NUM> using an NG2 interface for control-plane signaling and using an NG3 interface for user-plane data communications, at <NUM>. In addition to connections to core networks <NUM>, base stations <NUM> can communicate with each other. The base stations <NUM> and <NUM> communicate using an Xn interface at <NUM>, for instance. The base stations <NUM> and <NUM> communicate using an X2 interface at <NUM>. The base stations <NUM> and <NUM> can communicate using an Xn interface at <NUM> to execute a handover procedure.

The 5GC <NUM> includes an Access and Mobility Management Function <NUM> (AMF <NUM>) that provides control-plane functions such as registration and authentication of multiple UE <NUM>, authorization, mobility management, or the like in the <NUM> NR network. The EPC <NUM> includes a Mobility Management Entity <NUM> (MME <NUM>) that provides control-plane functions such as registration and authentication of multiple UE <NUM>, authorization, mobility management, or the like in the E-UTRA network. The AMF <NUM> and the MME <NUM> communicate with the base stations <NUM> in the RANs <NUM> and also communicate with multiple UE <NUM> through the base stations <NUM>.

The UE <NUM> supports eLTE or a variety of different RATs, such as <NUM> NR and <NUM>. Different situations can cause the UE <NUM> to transition among different resource control states as determined by the RAT. Example resource control states include a connected state in which the UE <NUM> establishes a wireless connection to a network using the base station <NUM>, an inactive state in which the UE <NUM> suspends the wireless connection to the network, or an idle state in which the UE <NUM> releases the wireless connection to the network. While in the inactive state, for example, the UE <NUM> performs the cell-selection procedure. In some cases, the cell-selection procedure selects a second base station that supports a core-network type that is different from the core-network type supported by the previous cell. As such, the selected base station may not support the inactive state or may not enable a wireless connection to a network to be resumed from the inactive state through a connection-resume procedure (e.g., a radio-resource-control (RRC) connection-resume procedure). In general, the connection-resume procedure enables the UE <NUM> to transition from the inactive state to the connected state and resume the connection to the RAN <NUM>. Components of the UE <NUM> are further described with respect to <FIG>.

<FIG> illustrates an example device diagram <NUM> of the UE <NUM>. The UE <NUM> can include additional functions and interfaces that are omitted from <FIG> for the sake of clarity. In the depicted configuration, the UE <NUM> includes antennas <NUM>, a radio-frequency (RF) front end <NUM> (RF front end <NUM>), a radio-frequency transceiver, including, for example, an LTE transceiver <NUM>, and/or a <NUM> NR transceiver <NUM> for communicating with one or more base stations <NUM> in the RAN <NUM>. The RF front end <NUM> couples or connects the LTE transceiver <NUM> and the <NUM> NR transceiver <NUM> to the antennas <NUM> to facilitate various types of wireless communication. The antennas <NUM> can include an array of multiple antennas that are configured similar to or differently from each other. The antennas <NUM> and the RF front end <NUM> are tuned to one or more frequency bands defined by the 3GPP LTE and <NUM> NR communication standards and implemented by the LTE transceiver <NUM> and/or the <NUM> NR transceiver <NUM>.

The UE <NUM> also includes one or more processors <NUM> and memory system including, for example, computer-readable storage media <NUM> (CRM <NUM>). The processor <NUM> can be a single core processor or a multiple core processor composed of a variety of materials, such as silicon, polysilicon, high-K dielectric, copper, and so on. The computer-readable storage media excludes propagating signals and the CRM <NUM> includes any suitable memory or storage device, such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flash memory useable to store device data <NUM> of the UE <NUM>. The device data <NUM> includes user data, multimedia data, beamforming codebooks, applications, and/or an operating system of the UE <NUM>, which are executable by the processor <NUM> to enable user-plane communication, control-plane signaling, and user interaction with the UE <NUM>.

The CRM <NUM> also includes a resource control module <NUM>. Alternately or additionally, the resource control module <NUM> can be implemented in whole or part as hardware logic or circuitry integrated with or separate from other components of the UE <NUM>. The resource control module <NUM> implements an RRC layer, as described according to the wireless communication standard. The resource control module <NUM> determines the resource control state (e.g., the connected state, the inactive state, or the idle state) and performs operations according to the resource control state. Instead of directly performing a connection-resume procedure, the resource control module <NUM> evaluates a core-network type of a currently selected cell. If the core-network type does not support the current resource control state or differs from a previous cell's core-network type, the resource control module <NUM> performs other actions instead of performing the connection-resume procedure. The resource control module <NUM> can at least partially implement handling an attempt to resume a wireless connection using a base station that supports a different core-network type, as further described in <FIG>.

<FIG> illustrates another example environment <NUM> in which the UEs <NUM> and <NUM> move to different geographical locations that are serviced by different base stations <NUM>, <NUM>, and <NUM> of <FIG>. In this example, the base station <NUM> is a gNB and supports the 5GC <NUM>. In contrast, the base station <NUM> is an ng-eNB or an eNB that supports the EPC <NUM>. The base station <NUM> is another ng-eNB that supports both the 5GC <NUM> and EPC <NUM>.

Consider that the UE <NUM> supports eLTE and is positioned at a first location <NUM>, which is proximate to the base station <NUM>. The UE <NUM> performs a cell-selection procedure that selects the base station <NUM>, establishes a wireless link <NUM> with the base station <NUM>, and operates in a connected state <NUM>. After some period of time, the UE <NUM> transitions from the connected state <NUM> to an inactive state <NUM>. In some cases, the UE <NUM> receives a request message from the base station <NUM> (shown in <FIG>) that directs the UE <NUM> to transition from the connected state <NUM> to the inactive state <NUM>. The request message can be a radio-resource-control (RRC) connection-release message.

While in the inactive state <NUM>, the UE <NUM> moves to a second location <NUM>, which is proximate to the base station <NUM>. The UE <NUM> performs a second cell-selection procedure to select or determine a second base station. The cell-selection procedure can alternatively be referred to as a cell-reselection procedure, which enables the UE <NUM> to change or switch to a different base station <NUM> within the RAN <NUM>. In this example, the UE <NUM> selects the base station <NUM>, which supports the EPC <NUM> and not the 5GC <NUM>. Consequently, the base station <NUM> does not support the inactive state <NUM> and does not support a connection-resume procedure that enables the UE <NUM> to transition from the inactive state <NUM> to the connected state <NUM>. Since the currently selected base station <NUM> does not support the inactive state <NUM>, a future attempt to perform the connection-resume procedure will fail.

A similar problem occurs if the UE <NUM> performs an inter-RAT cell-selection procedure, as described with respect to UE <NUM>. Consider that the UE <NUM> is positioned at a third location <NUM>, which is proximate to the base station <NUM>. The UE <NUM> performs a cell-selection procedure that selects the base station <NUM>, establishes the wireless link <NUM> with the base station <NUM>, and operates in the connected state <NUM>. After some time period, the UE <NUM> transitions from the connected state <NUM> to the inactive state <NUM>, similar to the UE <NUM>. Additionally, the UE <NUM> moves to a fourth location <NUM>, which is proximate to the base station <NUM>. At the fourth location <NUM>, the UE <NUM> performs a cell-selection procedure that selects the base station <NUM>, which supports a different core-network type compared to the core-network type supported by the base station <NUM>. Since the core-network type supported by the base station <NUM> does not support the inactive state <NUM>, a future attempt to perform the connection-resume procedure while the base station <NUM> is selected will fail.

To avoid wasting network resources or delaying communications that could be caused by a connection-resume procedure failure, the UE <NUM> performs other actions instead of performing the connection-resume procedure, as further described in <FIG>. Although the UEs <NUM> and <NUM> are described as being in the inactive state <NUM>, these techniques can be applied to other types of resource control states that may not be supported by the selected base station <NUM>.

<FIG> illustrates example data and control transactions <NUM> between the UE <NUM>, the first base station <NUM> or <NUM>, and the second base station <NUM>. In this example, the first base station <NUM> or <NUM> supports a first core-network (CN) type <NUM> and the second base station <NUM> supports a second core-network type <NUM>, which differs from the first core-network type <NUM>. As an example, the first core-network type <NUM> includes the 5GC <NUM> and the second core-network type <NUM> includes the EPC <NUM>.

At <NUM>, the first base station <NUM> or <NUM> and the UE <NUM> perform a connection-establishment procedure, which enables the UE <NUM> to wirelessly connect to the RAN <NUM> using the base station <NUM> or <NUM>.

At <NUM>, the UE <NUM> operates in the connected state <NUM>.

At <NUM>, the first base station <NUM> or <NUM> sends a request message <NUM> to the UE <NUM>. The request message <NUM> directs the UE <NUM> to transition from the connected state <NUM> to the inactive state <NUM>. In some cases, the request message <NUM> specifies a duration <NUM> for which the UE <NUM> operates in the inactive state <NUM> prior to performing a connection-resume procedure. An example request message <NUM> includes the RRC connection-release message, as described above with respect to <FIG>.

At <NUM>, the UE <NUM> transitions from the connected state <NUM> to the inactive state <NUM> and operates in the inactive state <NUM> according to the request message <NUM>.

At <NUM>, the UE <NUM> additionally sets a timer that triggers a connection-resume procedure upon expiration. In some cases, the UE <NUM> sets a duration of the timer based on a predetermined amount of time that is specified by the computer-readable storage media <NUM> of the UE <NUM>. Alternatively, the UE <NUM> sets the duration of the timer according to the duration <NUM> specified by the request message <NUM>.

At <NUM>, the UE <NUM> performs a cell-selection procedure that selects the second base station <NUM>. In some cases, the UE <NUM> selects the second base station <NUM> instead of the first base station <NUM> or <NUM> because the UE <NUM> moved to a new location that is closer to the second base station <NUM> (relative to the first base station <NUM> or <NUM>). As an example, the UE <NUM> moves to the second location <NUM> or the fourth location <NUM> shown in <FIG>.

At <NUM>, the UE <NUM> receives system information <NUM> from the second base station <NUM>. The system information <NUM> informs the UE <NUM> of the second core-network type <NUM> supported by the second base station <NUM>.

At <NUM>, the UE <NUM> determines that the first core-network type <NUM> supported by the first base station <NUM> or <NUM> differs from the second core-network type <NUM> supported by the second base station <NUM>. Consequently, a connection-resume procedure with the selected base station <NUM> may fail. The UE <NUM> can also determine that a future connection-resume procedure will fail based on a determination that the second core-network type <NUM> does not support the inactive state <NUM> (e.g., the current resource control state of the UE <NUM>).

At <NUM>, the UE <NUM> detects a trigger that initiates a connection-resume procedure. One example trigger includes an expiration of the timer <NUM>, which was previously set at <NUM>. A second example trigger includes a request to perform a radio-access-network notification-area (RNA) update <NUM>. The RNA update <NUM> provides a single identity (e.g., a RAN area identity, a cell identity, or a Public Land Mobile Network (PLMN) identity) or a list of identities (e.g., a list of cell identities) to the UE <NUM>. In some situations, the RNA update <NUM> is triggered if a RAN notification area associated with the selected base station (e.g., the second base station <NUM>) differs from the RAN notification area associated with the previously-selected base station (e.g., the first base station <NUM> or <NUM>). The system information <NUM> can provide the RAN notification area associated with the second base station <NUM> to the UE <NUM>. A third example trigger includes a message <NUM> from an upper layer, which triggers the RNA update <NUM> or the connection-resume procedure.

At <NUM>, the UE <NUM> performs one or more operations instead of the connection-resume procedure. In particular, when it is determined that the first core-network type <NUM> differs from the second core-network type <NUM> the UE <NUM> releases the wireless connection to the RAN <NUM> (e.g., transitions to the idle state), performs a connection-establishment procedure with the base station <NUM>, postpones the connection-resume procedure, and/or sends a message to an upper layer, as further described with respect to <FIG>. By determining that the first core-network type <NUM> differs from the second core-network type <NUM> at <NUM>, the UE <NUM> can take action to avoid attempting a connection-resume procedure that wastes network resources or delays communications.

<FIG> depicts an example method <NUM> for handling an attempt to resume a wireless connection using a base station that supports a different core-network type. Method <NUM> is shown as a set of operations (or acts) performed but not necessarily limited to the order or combinations in which the operations are illustrated. Further, any of one or more of the operations may be repeated, combined, reorganized, skipped, or linked to provide a wide array of additional and/or alternate methods. In portions of the following discussion, reference may be made to environment <NUM> of <FIG> or <NUM> of <FIG> and entities detailed in <FIG>, reference to which is made for example only. The techniques are not limited to performance by one entity or multiple entities operating on one device.

At <NUM>, a UE establishes a wireless connection to a network using a first base station that supports a first core-network type. For example, the UE <NUM> establishes a wireless link <NUM> to the RAN <NUM> of <FIG> using the base station <NUM>, as shown in <FIG>. In particular, the UE <NUM> performs a connection-establishment procedure (shown in <FIG>) as specified by the wireless communication standard. The UE <NUM> also determines that the base station <NUM> supports the first core-network type <NUM>, such as the 5GC <NUM>, based on system information provided by the base station <NUM>. In <FIG>, the UE <NUM> establishes a wireless link <NUM> to the RAN <NUM> using the base station <NUM>, which is implemented as a ng-eNB that supports both the 5GC <NUM> and the EPC <NUM>. Additionally, or alternatively, the UE <NUM> establishes a wireless link <NUM> to the RAN <NUM> using the base station <NUM>, which is implemented as a gNB that supports the 5GC <NUM>.

At <NUM>, the UE suspends the wireless connection to the network. For example, the UE <NUM> suspends the connection to the RAN <NUM>. In some cases, the UE <NUM> suspends the connection responsive to receiving the request message <NUM> of <FIG> (e.g., an RRC connection-release message) from the base station <NUM>. The request message directs the UE <NUM> to transition from the connected state <NUM> to the inactive state <NUM>. Although described with respect to the inactive state <NUM>, this step may alternatively involve transitioning to any second resource control state that is not supported by a second core-network type <NUM>.

At <NUM>, the UE performs a cell-selection procedure that selects a second base station. For example, the UE <NUM> performs the cell-selection procedure, which selects the base station <NUM>. Continuing with the above example, the cell-selection procedure is performed while the UE <NUM> is in the inactive state <NUM>.

At <NUM>, the UE processes system information received from the second base station to determine that the second base station supports a second core-network type. For example, UE <NUM> processes the system information <NUM> to determine that the base station <NUM> supports the second core-network type <NUM>. The system information <NUM> is received from the base station <NUM>, as shown at <NUM> in <FIG>.

At <NUM>, the UE determines that the second core-network type is different from the first core-network type. For example, the UE <NUM> determines that the second core-network type <NUM> is different from the first core-network type <NUM>. In particular, this can include determining that at least one difference between the first core-network type <NUM> and the second core-network type <NUM> is such that a connection-resume procedure with the second base station <NUM> may fail. In an example, determining that the second core-network type <NUM> is different from the first core-network type <NUM> includes determining that the second core-network type <NUM> and first core-network type <NUM> support different resource control states and/or different connection procedures. The UE <NUM> makes this determination based on system information <NUM> that is provided by the first base station <NUM> (e.g., the base station <NUM> or the base station <NUM>) and the second base station <NUM>.

As an example, the second core-network type <NUM> includes the EPC <NUM> and the first core-network type <NUM> includes the 5GC <NUM>. Unlike the 5GC <NUM>, the EPC <NUM> does not support the UE <NUM> in an inactive state <NUM> and does not support a connection-resume procedure that enables the UE <NUM> to transition from the inactive state <NUM> to the connected state <NUM>. Therefore, the UE <NUM> determines that the second core-network type <NUM> is different from the first core-network type <NUM>.

At <NUM>, the UE detects a trigger that initiates a connection-resume procedure. For example, the UE <NUM> detects at least one of the following types of triggers: an expiration of a timer <NUM> that directs the UE <NUM> to perform the connection-resume procedure, a request to perform an RNA update <NUM>, or a message <NUM> from the upper layer that directs the UE <NUM> to perform the connection-resume procedure, as described above with respect to <FIG>. To avoid performing a connection-resume procedure with the second base station <NUM>, which may fail due to the differences between the core-network types (e.g., differences between the EPC <NUM> and the 5GC <NUM>), the UE <NUM> performs at least one of the operations at <NUM>-<NUM> instead of performing the connection-resume procedure.

At <NUM>, the UE releases the wireless connection to the network. For example, the UE <NUM> releases the wireless connection to the RAN <NUM> by performing an RRC connection-release procedure. The UE <NUM> performs the RRC connection-release procedure with the first base station <NUM> or the second base station <NUM>. This procedure causes the UE <NUM> to transition from the inactive state <NUM> to an idle state, which is supported by the EPC <NUM>. Upon entering the idle state, the UE <NUM> deletes a resume UE context (e.g., an inactive UE context), a related identity (e.g., a resume identity or RNA identity), a security context, and so forth. In general, this step transitions the UE <NUM> from a current state that is not supported by the second core-network type <NUM> to a second state that is supported by the second core-network type <NUM>.

At <NUM>, the UE performs a connection-establishment procedure with the second base station. For example, the UE <NUM> performs the connection-establishment procedure with the base station <NUM> of <FIG> or <FIG> instead of performing the requested connection-resume procedure. The connection-establishment procedure is a procedure that is supported by the EPC <NUM>, and therefore may succeed. If the connection-establishment procedure fails, the UE <NUM> can proceed to release the connection at <NUM> and enter the idle state.

At <NUM>, the UE postpones the connection-resume procedure. For example, the UE <NUM> postpones the connection-resume procedure triggered at <NUM>. This postponement provides an opportunity for the UE <NUM> to perform a second cell-selection procedure. The UE <NUM> postpones the connection-resume procedure based on a predetermined amount of time or a timer. After the specified amount of time, the UE <NUM> proceeds to release the connection at <NUM>, perform the connection-establishment procedure at <NUM>, remain in the inactive state and send a message to an upper layer at <NUM>, or perform a second cell-selection procedure at <NUM>. In some cases, the UE <NUM> continues performing multiple cell-selection procedures <NUM> until a base station <NUM> is selected that supports the first core-network type <NUM> (e.g., the 5GC <NUM>). In other cases, the UE <NUM> keeps track of a timer or a total quantity of attempts and proceeds according to <NUM>, <NUM>, or <NUM> if a time limit or a maximum quantity of attempts has been reached. In some cases, the UE <NUM> continues performing cell-selection procedures at a predetermined time interval.

Claim 1:
A method performed by a user equipment, the method comprising:
establishing (<NUM>) a wireless connection to a network using a first base station that supports a first core-network type;
suspending (<NUM>) the wireless connection to the network;
performing a first cell-selection procedure (<NUM>) that selects a second base station;
processing (<NUM>) system information received from the second base station to determine that the second base station supports a second core-network type;
determining (<NUM>) that the second core-network type is different from the first core-network type; and
responsive to determining that the second core-network type is different, performing, in place of initiating a connection-resume procedure, one or more first operations comprising:
i) releasing (<NUM>) the wireless connection to the network;
ii) performing (<NUM>) a connection-establishment procedure with the second base station;
iii) performing a first instance (<NUM>) of postponing the connection-resume procedure, the first instance of postponing comprising:
initiating a first timer; and
performing a second cell-selection procedure responsive to an expiration of the first timer; or
iv) sending a message (<NUM>) to an upper layer, the message indicating an intent not to perform the connection-resume procedure.