RADIO RESOURCE CONTROL (RRC) LIGHT CONNECTION

Related Applications

This application claims priority to U.S. Application 62/455,489, entitled "NAS IMPACTS OF LIGHT CONNECTION," filed February 6, 2017.

Field

Embodiments of the present disclosure generally relate to the field of wireless

communication and particularly to the use of a light connection mode.

Background

Light connection mode is one possible mode in third generation partnership project (3GPP) networks that may reduce signaling overhead on radio or network interfaces while improving the access latency or power consumption for various user equipments (UEs). The signaling overhead optimizations (and resultant possible signaling reduction) may be due to handover optimizations that take into account factors like UE centric mobility. The signaling overhead optimizations may also be at least partially due to paging optimizations that consider limits to paging transmissions with a limited area. Finally, the signaling overhead optimizations may also be at least partially due to reduced core network (CN) signaling over the SI interface due to mobility and state transitions by making those transitions partially or wholly transparent to the CN.

Brief Description of the Drawings

Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

FIG. 1 depicts an architecture of a system of a network in accordance with some embodiments.

FIG. 2 illustrates an example call flow that may be used by the UE to enter and then send signals once in light connection mode.

FIG. 3 illustrates an example process related to light connection that may be performed by a UE.

FIG. 4 depicts example components of baseband circuitry and radio frequency circuitry in accordance with some embodiments.

FIG. 5 depicts example interfaces of baseband circuitry in accordance with some embodiments.

FIG. 6 is an illustration of a control plane protocol stack in accordance with some embodiments.

FIG. 7 illustrates components of a core network in accordance with some embodiments. FIG. 8 depicts a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein.

Detailed Description

Generally, embodiments herein relate to signaling procedures or other procedures that may be performed by a UE in a light connected mode, as described herein.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure.

Various operations may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed or described operations may be omitted in additional embodiments.

For the purposes of the present disclosure, the phrases "A or B," "A and/or B," and "A/B" mean (A), (B), or (A and B).

The description may use the phrases "in an embodiment," or "in embodiments," which may each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present disclosure, are synonymous.

FIG. 1 illustrates an architecture of a system 100 of a network in accordance with some embodiments. The system 100 is shown to include a user equipment (UE) 101 and a UE 102. As used herein, the term "user equipment" or "UE" may refer to a device with radio communication capabilities and may describe a remote user of network resources in a communications network. The term "user equipment" or "UE" may be considered synonymous to, and may be referred to as, client, mobile, mobile device, mobile terminal, user terminal, mobile unit, mobile station, mobile user, subscriber, user, remote station, access agent, user agent, receiver, radio equipment, reconfigurable radio equipment, reconfigurable mobile device, etc. Furthermore, the term "user equipment" or "UE" may include any type of wireless/wired device or any computing device including a wireless communications interface. In this example, UEs 101 and 102 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks), but may also comprise any mobile or non-mobile computing device, such as consumer electronics devices, cellular phones, smartphones, feature phones, tablet computers, wearable computer devices, personal digital assistants (PDAs), pagers, wireless handsets, desktop computers, laptop computers, in-vehicle infotainment (IVI), in-car entertainment (ICE) devices, an Instrument Cluster (IC), head-up display (HUD) devices, onboard diagnostic (OBD) devices, dashtop mobile equipment (DME), mobile data terminals (MDTs), Electronic Engine Management System (EEMS), electronic/engine control units (ECUs), electronic/engine control modules (EC Ms), embedded systems, microcontrollers, control modules, engine management systems (EMS), networked or "smart" appliances, machine-type communications (MTC) devices, machine-to-machine (M2M), Internet of Things (IoT) devices, and/or the like.

In some embodiments, any of the UEs 101 and 102 can comprise an Internet of Things (IoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short-lived UE connections. An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity- Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network describes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with shortlived connections. The IoT UEs may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate the connections of the IoT network.

The UEs 101 and 102 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 110— the RAN 110 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), aNextGen RAN (NG RAN), or some other type of RAN. The UEs 101 and 102 utilize connections (or channels) 103 and 104, respectively, each of which comprises a physical communications interface or layer (discussed in further detail infra). As used herein, the term "channel" may refer to any transmission medium, either tangible or intangible, which is used to communicate data or a data stream. The term "channel" may be synonymous with and/or equivalent to "communications channel," "data communications channel," "transmission channel," "data transmission channel," "access channel," "data access channel," "link," "data link," "carrier," "radiofrequency carrier," and/or any other like term denoting a pathway or medium through which data is communicated. Additionally, the term "link" may refer to a connection between two devices through a Radio Access Technology (RAT) for the purpose of transmitting and receiving information. In this example, the connections 103 and 104 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile

Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a New Radio (NR) protocol, and the like.

In this embodiment, the UEs 101 and 102 may further directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may altematively be referred to as a sidelink (SL) interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical

Sidelink Broadcast Channel (PSBCH). In various implementations, the SL interface 105 may be used in vehicular applications and communications technologies, which are often referred to as V2X systems. V2X is a mode of communication where UEs (for example, UEs 101, 102) communicate with each other directly over the PC5/SL interface 105 and can take place when the UEs 101, 102 are served by RAN nodes 111, 112 or when one or more UEs are outside a coverage area of the RAN 110. V2X may be classified into four different types: vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to- network (V2N), and vehicle-to-pedestrian (V2P). These V2X applications can use "co- operative awareness" to provide more intelligent services for end-users. For example, RAN nodes 111, 112, application server 130, and pedestrian UEs 101, 102 may collect knowledge of their local environment (for example, information received from other vehicles or sensor equipment in proximity) to process and share that knowledge in order to provide more intelligent services, such as cooperative collision warning, autonomous driving, and the like. In these implementations, the UEs 101, 102 may be

implemented/employed as Vehicle Embedded Communications Systems (VECS) or vUEs.

The UE 102 is shown to be configured to access an access point (AP) 106 (also referred to as "wireless local area network (WLAN) node 106," "WLAN 106," "WLAN Termination 106" or "WT 106" or the like) via connection 107. The connection 107 can comprise a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein the AP 106 would comprise a wireless fidelity (WiFi®) router. In this example, the AP 106 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). In various

embodiments, the UE 102, RAN 110, and AP 106 may be configured to utilize LTE-

WLAN aggregation (LWA) operation and/or WLAN LTEAVLAN Radio Level Integration with IPsec Tunnel (LWIP) operation. The LWA operation may involve the UE 102 in RRC_CONNECTED being configured by a RAN node 111, 112 to utilize radio resources of LTE and WLAN. LWIP operation may involve the UE 102 using WLAN radio resources (e.g., connection 107) via Internet Protocol Security (IPsec) protocol tunneling to authenticate and encrypt packets (e.g., Internet Protocol (IP) packets) sent over the connection 107. IPsec tunneling may include encapsulating the entirety of original IP packets and adding a new packet header, thereby protecting the original header of the IP packets.

The RAN 110 can include one or more access nodes that enable the connections 103 and 104. As used herein, the terms "access node," "access point," or the like may describe equipment that provides the radio baseband functions for data and/or voice connectivity between a network and one or more users. These access nodes can be referred to as base stations (BS), NodeBs, evolved NodeBs (eNBs), next Generation NodeBs (gNB), RAN nodes, Road Side Units (RSUs), and so forth, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). The term "Road Side Unit" or "RSU" may refer to any transportation infrastructure entity implemented in or by a gNB/eNB/RAN node or a stationary (or relatively stationary) UE, where an RSU implemented in or by a UE may be referred to as a "UE-type RSU," and an RSU implemented in or by an eNB may be referred to as an "eNB-type RSU." The RAN 110 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 111, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 112.

Any of the RAN nodes 111 and 112 can terminate the air interface protocol and can be the first point of contact for the UEs 101 and 102. In some embodiments, any of the RAN nodes 111 and 112 can fulfill various logical functions for the RAN 110 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In accordance with some embodiments, the UEs 101 and 102 can be configured to communicate using Orthogonal Frequency -Division Multiplexing (OFDM)

communication signals with each other or with any of the RAN nodes 111 and 112 over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, an Orthogonal Frequency-Division Multiple Access (OFDMA) communication technique (e.g., for downlink communications) or a Single Carrier Frequency Division Multiple Access (SC-FDMA) communication technique (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signals can comprise a plurality of orthogonal subcarriers.

In some embodiments, a downlink resource grid can be used for downlink transmissions from any of the RAN nodes 111 and 112 to the UEs 101 and 102, while uplink transmissions can utilize similar techniques. The grid can be a time-frequency grid, called a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. Such a time-frequency plane representation is a common practice for OFDM systems, which makes it intuitive for radio resource allocation. Each column and each row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in a radio frame. The smallest time-frequency unit in a resource grid is denoted as a resource element. Each resource grid comprises a number of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block comprises a collection of resource elements; in the frequency domain, this may represent the smallest quantity of resources that currently can be allocated. There are several different physical downlink channels that are conveyed using such resource blocks.

The physical downlink shared channel (PDSCH) may carry user data and higher-layer signaling to the UEs 101 and 102. The physical downlink control channel (PDCCH) may carry information about the transport format and resource allocations related to the PDSCH channel, among other things. It may also inform the UEs 101 and 102 about the transport format, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request) information related to the uplink shared channel. Typically, downlink scheduling

(assigning control and shared channel resource blocks to the UE 102 within a cell) may be performed at any of the RAN nodes 111 and 112 based on channel quality information fed back from any of the UEs 101 and 102. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of the UEs 101 and 102. The PDCCH may use control channel elements (CCEs) to convey the control information. Before being mapped to resource elements, the PDCCH complex-valued symbols may first be organized into quadruplets, which may then be permuted using a sub-block interleaver for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements known as resource element groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped to each REG. The PDCCH can be transmitted using one or more CCEs, depending on the size of the downlink control information (DCI) and the channel condition. There can be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation level, L=l, 2, 4, or 8).

Some embodiments may use concepts for resource allocation for control channel information that are an extension of the above-described concepts. For example, some embodiments may utilize an enhanced physical downlink control channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more enhanced control channel elements (ECCEs). Similar to above, each ECCE may correspond to nine sets of four physical resource elements known as enhanced resource element groups (EREGs). An ECCE may have other numbers of EREGs in some situations. The RAN 110 is shown to be communicatively coupled to a CN 120— via an SI interface 113. In embodiments, the CN 120 may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN. In this embodiment the SI interface 113 is split into two parts: the Sl-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the S 1- mobility management entity (MME) interface 115, which is a signaling interface between the RAN nodes 111 and 112 and MMEs 121.

In this embodiment, the CN 120 comprises the MMEs 121, the S-GW 122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc.

The S-GW 122 may terminate the SI interface 113 towards the RAN 110, and routes data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities may include lawful intercept, charging, and some policy enforcement.

The P-GW 123 may terminate an SGi interface toward a PDN. The P-GW 123 may route data packets between the EPC network 120 and external networks such as a network including the application server 130 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. Generally, the application server 130 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this embodiment, the P-GW 123 is shown to be communicatively coupled to an application server 130 via an IP communications interface 125. The application server 130 can also be configured to support one or more communication services (e.g., Voice-over-Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 101 and 102 via the CN 120.

The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Enforcement Function (PCRF) 126 is the policy and charging control element of the CN 120. In a non-roaming scenario, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 130 via the P-GW 123. The application server 130 may signal the PCRF 126 to indicate a new service flow and select the appropriate Quality of Service (QoS) and charging parameters. The PCRF 126 may provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) with the appropriate traffic flow template (TFT) and QoS class of identifier (QCI), which commences the QoS and charging as specified by the application server 130.

Generally, the evolved packet system (EPS) mobility management (collectively, EMM) layer is a sub-layer of the non-access-stratum (NAS) layer that allows communication between a UE and an element of the CN such as the MME. In order for a UE and an MME to successfully exchange NAS messages with each other, a signaling connection for exchanging NAS messages must be established between them. This NAS connection may be referred to as the EPS Connection Management (ECM) connection. The ECM connection may be considered to be a logical connection that includes an RRC connection between a UE and a RAN node such as an eNB. The ECM connection may further include, for example, an SI signaling connection between the RAN node and an MME. In some wireless networks, light connection mode may be one possible mode in 3GPP networks that may reduce signaling overhead on radio or network interfaces while improving the access latency or power consumption for various UEs. Generally, light connection may be described at two layers which may overlap, but may include different signaling. At the RRC layer, there may be light connection over the RRC link (i.e., between the UE 101, 102 and the RAN node 111, 112). This mode may be referred to herein as "RRC CONNECTED with a light RRC connection" mode. There may also exist a RRC connection without light connection which may be referred to herein as the "RRC CONNECTED without light connection" mode. At the EMM layer, there may similarly be an "EMM-CONNECTED mode with a light connection" and a "EMM- CONNECTED mode without light connection" which may designate the light connection mode and the mode without light connection, respectively, at the EMM layer. It will be understood that these names are used herein as example identifiers and other embodiments may include similar modes that may have different names. In other words, the specific names used for these modes are not intended to be limiting. For example, in some embodiments the light connection mode related to EMM may be referred to as

"EMM LIGHT-CONNECTED mode." Generally, the RRC CONNECTED with a light RRC connection mode and the EMM-CONNECTED mode with a light connection may be collectively referred to herein as the "light connection mode."

For the UE state transition from the RRC CONNECTED without light connectionmode to an RRC CONNECTED with a light RRC connection mode, the eNB may transmit to the UE 101, 102 an RRCConnectionRelease message along with an indication to enter into the RRC CONNECTED with a light RRC connection mode. In some embodiments, the indication may be an RRC-LightConnectionlndication indication, message, information element (IE), or some other type of indication.

Upon entering into RRC CONNECTED with a light RRC connection mode, the UE 101, 102 may behave similarly to a UE in release-13 (Rel-13) user plane (UP) cellular internet of things (CIoT) optimizations. For example, from a UE modeling perspective, a UE 101, 102 in RRC CONNECTED with a light RRC connection mode may reuse legacy RRC resume mechanisms and messages for a resume procedure. Signal radio bearers (SRBs) and data radio bearers (DRBs) may be suspended, and the UE 101, 102 may perform idle mode procedures. Additionally or alternatively, UE access stratum (AS) context may be stored.

When the UE 101 , 102 is in the RRC CONNECTED with a light RRC connection mode, RAN -initiated paging mechanisms may be used. For example, when a RAN node 111, 112 such as an eNB receives downlink (DL) user data or signaling for the UE 101, 102, the RAN node 111, 112 may trigger paging to the UE 101, 102 via RRC and, if needed, via an X2 interface. This RAN-initiated paging may cause the UE 101, 102 to resume the RRC CONNECTED without light connection mode with the RAN node 111, 112.

Alternatively, the UE 101, 102 may resume RRC C ONNECTED without light connection mode upon initiation of mobile-originated (MO) data/signaling transfer. Moreover, paging occasion/paging frame (PO/PF) or paging messages checked by the UE 101, 102 during the RAN-initiated paging may be similar to those of the legacy 3GPP paging procedure, which may be initiated by the MME 121. For a UE state transition from the

RRC CONNECTED with a light RRC connection mode to the RRC C ONNECTED without light connection mode, the UE 101, 102 may initiate an RRC Connection

Resumption procedure of the light connected mode.

NAS Notification

It may be desirable for the UE non-access stratum (NAS) entity (described in further detail below) to know when the UE 101, 102 is in the EMM-CONNECTED mode with a light connection. Specifically, the UE behavior in the EMM-CONNECTED mode with a light connection may be different than the UE behavior in the EMM-CONNECTED mode without light connection, and so it may be desirable for the UE NAS entity to know that the UE 101, 102 is in the EMM-CONNECTED mode with a light connection.

As an example, legacy idle mode procedures such as public land mobile network (PLMN) selection (e.g., background search for high priority PLMN or other PLMN idle mode procedures) may be applied to the EMM-CONNECTED mode with a light connection. Additionally, in some embodiments a UE in EMM-CONNECTED mode without light connection may move to another cell only via network-controlled packet switched (PS) handover, but not via UE-controlled cell re-selection. This limitation on handover or cell reselection may have an impact on UE behavior.

Therefore, in some embodiments it may be desirable for the UE NAS entity to be aware of the fact that the UE 101, 102 is in the EMM-CONNECTED mode with a light connection. The UE NAS entity may be made aware of the UE 101, 102 being in the EMM- CONNECTED mode with a light connection by an indication received from the UE AS entity, as described in further detail below.

Ciphering of the First NAS Message

When the EMM layer is in the EMM-CONNECTED mode with a light connection, the MME 121 may generally only accept ciphered messages (though some exceptions may exist such as an Attach Request or a tracking area update (TAU) request). This acceptance of only ciphered message by the MME 121 may be different from legacy 3GPP (Rel-13) Suspend or Resume procedures, where the MME may be in an EMM Idle mode and consequently expect the first NAS message to be unciphered. For example, a Detach Request may need to be sent as an unciphered message from the UE for the legacy Rel-13 Resume procedure, but may need to be transmitted as a ciphered message in the EMM- CONNECTED mode with a light connection.

Therefore, it may be desirable in some embodiments to assume, for the sake of ciphering the first NAS message, that the UE 101, 102 is in the EMM-CONNECTED mode without light connection when, in fact, the UE 101, 102 is in the EMM-CONNECTED mode with a light connection. Under this assumption, the UE 101, 102 may automatically apply ciphering to the first NAS message.

Alternatively, if it is assumed that the UE 101, 102 is in the EMM-CONNECTED mode with a light connection for the sake of ciphering the first NAS message, then the rules for ciphering may need to be similar to those discussed in the 3GPP specifications for the EMM-CONNECTED mode without light connection, rather than those for the Rel-13 EMM Idle mode.

In some embodiments, due to the requirement for ciphering of the first NAS message, it may not be possible to re-use the legacy "fallback" mechanism specified for the Rel-13 Resume procedure. Specifically, in this legacy procedure, the RRC connection may be absent and the RAN node may respond to the Resume Request from the UE with an RRC Connection Setup message instead of a Resume message. The UE in turn may reply with an RRC Connection Setup Complete message that includes an unciphered NAS message. Instead of this legacy fallback procedure, it may be desirable for the access stratum (AS) layer, and particularly the UE AS entity (discussed in greater detail below), to inform the UE NAS entity about the absence of an RRC connection so that the UE NAS entity may trigger one or more resultant actions.

For example, if the UE NAS entity in a legacy network intended to send a ciphered Detach Request message, the UE NAS entity may need to request the UE AS entity to establish an RRC connection with the RAN node. The UE NAS entity may also need to send an unciphered Detach Request as an initial NAS message. By contrast, if the requirement that the first NAS message be ciphered is active, then the UE 101, 102 (and specifically the UE NAS entity) may need to initiate a service request procedure and subsequently send a session management message.

RRC Establishment Cause Values When Resuming from Light Connected State

In some embodiments, MO data/signaling or mobile terminated (MT) calls may be used as resume cause values when the UE 101, 102 resumes from a light connection mode such as an RRC CONNECTED with a light RRC connection mode or an EMM-CONNECTED mode with a light connection. However, some embodiments may consider other resume cause values when resuming from the light connection mode. These resume cause values may include, for example, "highPriority Access," "emergency," "exceptionData" (for narrowband Internet of Things (NB-IoT)), or "delay TolerantAccess" resume cause values which may be included in one or more messages, indications, IEs, elements, etc. In these cases, it may be desirable for the UE NAS entity to notify the UE AS entity of the establishment cause or call type related to the resume cause value.

In some embodiments, it may be desirable to differentiate the resume cause value of "highPriority Access" or "emergency" from other resume cause values. For example, the resume cause value "highPriority Access" may relate to a characteristic of the device that may not change often, and it may be preferable if the access of high priority UEs are still differentiated while in the light connection state.

If the UE 101, 102 already has an emergency packet data network (PDN) connection, it may not be clear if the UE 101, 102 should go to the light connection mode. However, in some cases if the UE 101, 102 is in the light connection mode and establishes an emergency PDN connection in order to set up an IP multimedia service (collectively, IMS) emergency call, then the UE NAS entity may provide information related to the emergency PDN connection to the UE AS entity when resuming from the

RRC CONNECTED with a light RRC connection mode. Therefore, it may be desirable for "emergency" to be a resume cause value when the UE 101, 102 is resuming from a light connection mode.

More specifically, it may be desirable for there to be both "high Priority Access" and "emergency" resume cause values when resuming from the RRC CONNECTED with a light RRC connection mode. When the UE 101, 102 is resuming from the

RRC CONNECTED with a light RRC connection mode, the resume cause may be set as follows:

if upper layer informs of an emergency call:

set the resumeCause to emergency;

else if upper layer informs of highPriority Access:

set the resumeCause to highPriority Access;

else if resuming due to paging: set the resumeCause to mt- Access;

if resuming due to RRC signaling:

set the resumeCause to mo-Signaling

else:

set the resumeCause to mo-Data;

Idle Mode Procedures

When in the light connection mode, some elements of PLMN selection such as a

Background search for a High Priority PLMN may be used by a UE 101, 102. In some embodiments, the UE 101, 102 may be able to trigger cell changes in a different PLMN (even though the UE 101, 102 may be in RRC CONNECTED with a light RRC connection mode). That is, the UE 101, 102 may be able to trigger movement to a cell of a different PLMN.

This PLMN selection may be performed similar to legacy procedures in 3GPP specifications. Specifically, 3GPP technical specifications (TSs) such as TS36.331 and TS23.122 may be amended to specify that the UE 101, 102 can perform Idle mode procedures in the evolved universal terrestrial radio access (E-UTRA) when in

RRC CONNECTED with a light RRC connection mode. TS 25.331 vl4.1.0 (December, 2016) at § 7.2.2.1 may describe the background search as follows:

In the URA PCH or CELL PCH state the UE shall perform the following actions:

NOTE. . .

l>if the UE is "in service area":

2> maintain up-to-date system information as broadcast by the serving cell as specified in the subclause 8.1.1 ;

2> perform cell reselection process as specified in [4];

2> perform a periodic search for higher priority PLMNs as specified in

[25], unless the UE is receiving MBMS services via p-t-m radio bearers;

NOTE: If the DRX cycle length is 80ms, then a search for higher priority PLMNs may not identify all the available PLMNs due to the paging occasion on the current serving cell coinciding with the MIB of the cell of interest. Generally, in legacy networks without light connection, the UE AS entity may provide a list of PLMNs that are available for PLMN selection by the UE. The UE NAS entity may be in a packet switched (PS) mobility management (collectively, PMM)-Connected mode. Then, the UE AS entity may need to be in a legacy RRC Connected state in which it can perform cell re-selection (or, more precisely, in Cell PCH or URA PCH mode and, in some embodiments, not in Cell DCH mode). In this embodiment, the UE NAS entity can ask the UE AS entity to re-select to a cell of the other PLMN. From the point of view of the CN, this may appear simply as cell re-selection by the UE.

Embodiments herein may apply a similar procedure to a UE 101, 102 in

RRC CONNECTED with a light RRC connection mode. More specifically, a UE 101, 102 in the RRC CONNECTED with a light RRC connection mode may be able to perform a similar PLMN search as a new task for that mode. However, the UE 101, 102 may also need to be able to check whether there can be a collision between paging in the cell to which the UE 101, 102 is currently connected and a master information block (MIB) of neighboring cells. In some embodiments, the UE 101, 102 (and particularly the UE NAS entity or the UE AS entity) may not need to know whether the UE 101, 102 is in the EMM-CONNECTED mode without light connection or the EMM-CONNECTED mode with a light connection. Rather, the UE 101, 102 (and particularly the UE NAS entity) may only need to be prepared to receive a list of available PLMNs and react to the list while remaining in the EMM-CONNECTED mode.

As an alternative option, higher priority PLMN search for a UE 101, 102 in

RRC CONNECTED with a light RRC connection mode may be disabled by disabling light connection for UEs that are not on their home PLMN (HPLMN) or an equivalent HPLMN (eHPLMN). Specifically, the MME 121 may disable the usage of

RRC CONNECTED with light RRC connection mode for UEs that are roaming (i.e., connected to a visited PLMN (VPLMN)). The MME 121 may inform the RAN node 111, 112 of the disablement of the light connection via SI signaling, and this information may be forwarded or transferred between various RAN nodes 111, 112 when

transmitting/fetching UE AS Context information via X2 or SI signaling. Notably, this disablement of light connection for roaming UEs may not impact UEs that operate in their HPLMN or eHPLMN.

Periodic TAU Functionality In some embodiments, periodic TAU functionality may still be desired, either on the NAS (i.e., the EMC) level or the RAS level. Specifically, in some embodiments there may be an error case where the RAN node 111, 112 needs to release the SI connection between the RAN node 111, 112 and the MME 121, and the MME 121 restarts a Mobile Reachable timer that relates to whether the MME 121 can communicate with a UE 101, 102. In this case, there is a risk that the UE 101, 102 may be implicitly detached if it is in a light connection mode because it may not initiate periodic TAU. As such, it may be desirable for the UE 101, 102 to perform a periodic update procedure on the RRC level with a periodic update timer that is smaller than or equal to the periodic TAU timer used by the MME 121 or RAN node 111, 112.

Impacts to 3 GPP TS 24.301

In order to implement various embodiments herein, it may be desirable to make one or more amendments to existing 3GPP TSs. Specifically, embodiments herein may be implemented through changes to 3GPP TS 24.301. For example, TS 24.301 may be amended to include the following new subclause:

5.3.A Light connection

If the UE supports light connection it indicates that to the network in the UE Network capability IE as part of the ATTACH REQUEST and TRACKING AREA UPDATE REQUEST messages. If the network supports light connection, the network may activate light connection in EMM-CONNECTED mode when user plane radio bearers have been set up. If light connection has been activated by the network and if the UE supports light connection then the UE enters a new state EMM- CONNECTED mode with light connection or EMM LIGHT- CONNECTED mode. The UE can use light connection only in the home PLMN. When the UE is roaming to a visited PLMN the MME disables the use of light RRC connection.

If the UE needs to resume from EMM-LIGHT-CONNECTED mode the

UE shall request the lower layer to resume the light connection with RRC establishment cause "High priority access AC 11 - 15", if the UE is configured to use AC 11 - 15 in the selected PLMN or with RRC establishment cause "emergency call" if the UE establishes or modifies a PDN connection for emergency bearer services. Upon indication from the lower layers that the RRC connection has been resumed when in EMM- CONNECTED mode with light connection, the UE shall enter EMM- CONNECTED mode without light connection. Upon indication from the lower layers that the RRC connection resume has failed due to network rejection when in EMM-CONNECTED mode with light connection, the UE shall enter EMM-IDLE mode.

In case of fallback to RRC connection establishment during resume from EMM-LIGHT-CONNECTED mode, legacy behaviour is applicable. When a UE in light RRC connection receives the RRCConnectionSetup message in response to RRCConnectionResumeRequest, the UE access stratum informs the UE NAS that the RRC connection resume has been fallbacked, and UE AS discards UE AS context and resumeldentity.

When the UE is in EMM-LIGHT-CONNECTED mode and is camped on its home PLMN (HPLMN) or equivalent home PLMN (EHPLMN), the UE shall perform PLMN selection, similar to that in UTRAN RRC connected mode as specified in 3 GPP TS 23.122.

Additionally or alternatively, § 5.5.1.2.2 of TS 24.401 may be amended to include the following statement:

Attach procedure initiation

If the UE supports light connection and is not roaming in a visited PLMN, then the UE shall set the LC bit to "light connection supported" in the UE network capability IE of the ATTACH REQUEST message.

Additionally or alternatively, § 5.5.3.2.2 of TS 24.401 may be amended to include the following statement:

5.5.3.2.2 Normal and periodic tracking area updating procedure initiation For all cases except case b, if the UE supports light connection and is not roaming in a visited PLMN, then the UE shall set the LC bit to "light connection supported" in the UE network capability IE of the TRACKING AREA UPDATE REQUEST message.

Additionally or alternatively, § 9.9.3.34 of TS 24.401 may be amended to include the following element (introduced elements related to embodiments herein underlined for emphasis):

9.9.3.34 UE network capability

The purpose of the UE network capability information element is to provide the network with information concerning aspects of the UE related to EPS or interworking with GPRS. The contents might affect the manner in which the network handles the operation of the UE. The UE network capability information indicates general UE characteristics and it shall therefore, except for fields explicitly indicated, be independent of the frequency band of the channel it is sent on.

The UE network capability information element is coded as shown in figure 9.9.3.34.1 and table 9.9.3.34.1.

The UE network capability is a type 4 information element with a minimum length of 4 octets and a maximum length of 15 octets.

8 7 6 5 4 3 2 1

UE network capability IEI octet 1

Length of UE network capability contents octet 2

128- 128- 128-

EEAO EEA4 EEA5 EEA6 EEA7 octet 3

EEA1 EEA2 EEA3

128- 128- 128-

EIAO EIA4 EIA5 EIA6 EIA7 octet 4

EIA1 EIA2 EIA3

octet

UEAO UEA1 UEA2 UEA3 UEA4 UEA5 UEA6 UEA7

5* octet

UCS2 UIA1 UEA2 UEA3 UEA4 UEA5 UEA6 UEA7

6*

ProSe- H.245- ACC- lxSR octet

ProSe LPP LCS NF

dd ASH CSFB VCC 7*

HC-CP ERw/o Sl-U UP CP Prose- octet ePCO ProSe-dc

CIoT PDN data CIoT CIoT relay 8*

0 0 0 V2X octet

0 Spare 0 Spare LC multipleDRB

Spare Spare Spare PC5 9* octet

0 0 0 0 0 0 0 0

10* -

Spare

15*

Figure 9.9.3.34.1: UE network capability information element

V2X communication over PC5 (V2X PC5) (octet 9, bit 2)

This bit indicates the capability for V2X communication over PC5.

V2X communication over PC5 not supported

V2X communication over PC5 supported

Light Connection (LC) (octet 9. bit 3)

This bit indicates the UE capability for light connection.

0 light connection not supported

1 light connection supported

All other bits in octet 9 to 15 are spare and shall be coded as zero, if the respective octet is included in the information element.

FIG. 2 illustrates an example call flow that may be used by the UE to enter and then send signals once in light connection mode. Specifically, FIG. 2 illustrates an example of a signal call flow that may be used to enter into light connection mode and then transmit ciphered NAS messages, as described above. The call flow may begin by a UE such as UE 101 or 102 indicating to RAN node 111 or 112 that the UE supports UE light connection mode at 212. Such an indication may be, for example, through the transmission of the UE network capability IE as described above with the LC bit set to a value of "1," or through some other type of indication. In some embodiments, the indication or the IE may be, or may be an element of, an ATTACH REQUEST or a TAU REQUEST message.

The RAN node 111 or 112 may then query the MME 121 (or some other element of the CN) to identify whether the network supports the use of light connection mode by the UE 101 or 102 at 215. The MME 121 may decide whether to support use of light connection mode based on factors such as whether the UE is on an HPLMN or eHPLMN at 218, as described above. The support decision may additionally or alternatively be based on one or more other factors such as bandwidth, network load, UE load, QoS, or some other factor.

If the MME 121 identifies that use of light connection mode by the UE is supported, the MME 121 may transmit an indication of light connection support 221 to the RAN node 111 or 112 at 221, which is then forwarded to the UE 101 or 102 at 224. Based on this indication, the UE 101 or 102 may enter light connection mode at 227. Specifically, the UE 101 or 102 may enter into the RRC CONNECTED with a light RRC connection mode or the EMM-CONNECTED mode with a light connection. Even more specifically, the UE 101 or 102 may adopt one or more of the behaviors described above related to the light connection mode.

One such behavior may be, for example, transmission of a ciphered NAS Detach Request as described above in the subsection titled "Ciphering of the First NAS Message." Specifically, the UE 101 or 102 may transmit the ciphered NAS Detach Request to a RAN node 111 or 112 at 230, which may then forward it to the MME 121 at 233. The MME 121 may then generate one or more responses to the ciphered NAS Detach Request;

however, those specific responses are not further discussed with respect to this Figure.

FIG. 3 illustrates an example process related to light connection that may be performed by a UE such as UEs 101 or 102. Similarly to the process described above, the process may include the UE transmitting an indication that the UE supports light connection at 305. This element may be similar to element 212 and such an indication may be, for example, through the transmission of the UE network capability IE as described above with the LC bit set to a value of "1," or through some other type of indication. Similarly to above, in some embodiments the indication or the IE may be, or may be an element of, an ATTACH REQUEST or a TAU REQUEST message. The process may then include the UE receiving an indication that the network supports light connection at 310, and then entering into a light connection mode (e.g., the RRC CONNECTED with a light RRC connection mode or the EMM-CONNECTED mode with a light connection) at 315. Elements 310 and 315 may be respectively similar to elements 224 and 227, described above.

The process may then include the UE identifying, at 320, that it is to exit the light connection mode and then transmitting at 325 an indication that the UE is to exit the light connection mode. Specifically, the UE may identify at 320 that it needs to resume from the light connection mode and the indication at 325 may be a resume cause value as described above. For example, the UE may transmit at 325 an RRC establishment cause "High priority access AC 11 - 15," if the UE is configured to use AC 11 - 15 in the selected PLMN, which may be similar to the resume cause value of "highPriority Access" as described above. Additionally or alternatively, the UE may transmit at 325 an RRC establishment cause "emergency call" if the UE establishes or modifies a PDN connection for emergency bearer services, which may be similar to the resume cause value of "emergency" as described above. The identification at 320 may be by, for example, a UE NAS entity as described in further detail below. The transmission at 325 may be by, for example, a UE AS entity as described in further detail below.

The UE may then identify at 330 whether the exit from the light connection mode (i.e., the resume process) was successful. Such an identification may be based on an indication received by the UE from an MME, RAN node, or some other element external to the UE. Alternatively, such an identification may be based on a notification received by the UE NAS entity from the UE AS entity. If the exit was successful, then the UE, and specifically the UE NAS entity, may enter the EMM-CONNECTED mode without light connection or the RRC CONNECTED without light connection mode at 340. If the exit was not successful, then the UE, and specifically the UE NAS entity, may enter the EMM IDLE mode at 335.

It will be understood that the above processes and elements described above with respect to light connection are generally described with respect to 4G networks. However, in other embodiments the processes or techniques may be modified to be performed in fifth generation (5G) networks or some other network where UE use of light connection may be desirable.

FIG. 4 illustrates example components of baseband circuitry 404 and radio front end modules (RFEM) 415 in accordance with some embodiments. As shown, the RFEM 415 may include radio frequency (RF) circuitry 406, front-end module (FEM) circuitry 408, one or more antennas 410 coupled together at least as shown.

The baseband circuitry 404 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 404 may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry 406 and to generate baseband signals for a transmit signal path of the RF circuitry 406. Baseband processing circuity 410 may interface with application circuitry (not shown) for generation and processing of the baseband signals and for controlling operations of the RF circuitry 406. For example, in some embodiments, the baseband circuitry 404 may include a third generation (3G) baseband processor 404A, a fourth generation (4G) baseband processor 404B, a fifth generation (5G) baseband processor 404C, or other baseband processor(s) 404D for other existing generations, generations in development or to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). The baseband circuitry 404 (e.g., one or more of baseband processors 404A-D) may handle various radio control functions that enable

communication with one or more radio networks via the RF circuitry 406. In other embodiments, some or all of the functionality of baseband processors 404A-D may be included in modules stored in the memory 404G and executed via a central processing unit (CPU) 404E. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 404 may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 404 may include convolution, tail-biting convolution, turbo, Viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of

modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry 404 may include one or more audio digital signal processor(s) (DSP) 404F. The audio DSP(s) 404F may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry 404 may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 410 and the application circuitry may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 404 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 404 may support communication with an evolved universal terrestrial radio access network (EUTRAN) or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), or a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 404 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 406 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 406 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 406 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 408 and provide baseband signals to the baseband circuitry 404. RF circuitry 406 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 404 and provide RF output signals to the FEM circuitry 408 for transmission.

In some embodiments, the receive signal path of the RF circuitry 406 may include mixer circuitry 406a, amplifier circuitry 406b and filter circuitry 406c. In some embodiments, the transmit signal path of the RF circuitry 406 may include filter circuitry 406c and mixer circuitry 406a. RF circuitry 406 may also include synthesizer circuitry 406d for synthesizing a frequency for use by the mixer circuitry 406a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 406a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 408 based on the synthesized frequency provided by synthesizer circuitry 406d. The amplifier circuitry 406b may be configured to amplify the down-converted signals and the filter circuitry 406c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 404 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 406a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 406a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 406d to generate RF output signals for the FEM circuitry 408. The baseband signals may be provided by the baseband circuitry 404 and may be filtered by filter circuitry 406c.

In some embodiments, the mixer circuitry 406a of the receive signal path and the mixer circuitry 406a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and upconversion, respectively. In some embodiments, the mixer circuitry 406a of the receive signal path and the mixer circuitry 406a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 406a of the receive signal path and the mixer circuitry 406a of the transmit signal path may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry 406a of the receive signal path and the mixer circuitry 406a of the transmit signal path may be configured for super-heterodyne operation.

In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 406 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 404 may include a digital baseband interface to communicate with the RF circuitry 406.

In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect. In some embodiments, the synthesizer circuitry 406d may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 406d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 406d may be configured to synthesize an output frequency for use by the mixer circuitry 406a of the RF circuitry 406 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 406d may be a fractional N/N+l synthesizer.

In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 404 or the applications processor depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor.

Synthesizer circuitry 406d of the RF circuitry 406 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+1 (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 406d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 406 may include an IQ/polar converter.

FEM circuitry 408 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 410, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 406 for further processing. FEM circuitry 408 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 406 for transmission by one or more of the one or more antennas 410. In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry 406, solely in the FEM circuitry 408, or in both the RF circuitry 406 and the FEM circuitry 408.

In some embodiments, the FEM circuitry 408 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry 408 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry 408 may include an low noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 406). The transmit signal path of the FEM circuitry 408 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 406), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 410).

Processors of the application circuitry and processors of the baseband circuitry 404 may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry 404, alone or in combination, may be used to execute Layer 3, Layer 2, or Layer 1 functionality, while processors of the baseband circuitry 404 may utilize data (e.g., packet data) received from these layers and further execute Layer 4 functionality (e.g., transmission communication protocol (TCP) and user datagram protocol (UDP) layers). As referred to herein, Layer 3 may comprise a radio resource control (RRC) layer, described in further detail below. As referred to herein, Layer 2 may comprise a medium access control (MAC) layer, a radio link control (RLC) layer, and a packet data convergence protocol (PDCP) layer, described in further detail below. As referred to herein, Layer 1 may comprise a physical (PHY) layer of a UE/RAN node, described in further detail below. FIG. 5 illustrates example interfaces of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry 404 of FIG. 4 may comprise processors 404A-404E and a memory 404G utilized by said processors. Each of the processors 404A-404E may include a memory interface, 504A-504E, respectively, to send/receive data to/from the memory 404G.

The baseband circuitry 404 may further include one or more interfaces to

communicatively couple to other circuitries/devices, such as a memory interface 512 (e.g., an interface to send/receive data to/from memory external to the baseband circuitry 404), an application circuitry interface 514 (e.g., an interface to send/receive data to/from the application circuitry), an RF circuitry interface 516 (e.g., an interface to send/receive data to/from RF circuitry 406 of FIG. 4), a wireless hardware connectivity interface 518 (e.g., an interface to send/receive data to/from Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components), and a power management interface 520 (e.g., an interface to send/receive power or control signals to/from power management integrated circuitry (PMIC)).

In some embodiments, various baseband processors such as the 4G baseband processor 404b may include one or more additional logical entities. For example, the 4G baseband processor 404b as illustrated in FIG. 5 may include a UE NAS entity 525 and a UE AS entity 524. In embodiments, the UE NAS entity 525 may be a logical or physical entity implemented in hardware, firmware, software, or some combination thereof that is responsible for facilitating and controlling NAS communication between the UE 101, 102 and the MME 121. The UE AS entity 524 may be a logical or physical entity implemented in hardware, firmware, software, or some combination thereof that is responsible for facilitating and controlling AS communication such as RRC communication between the UE 101, 102 and the RAN nodes 111, 112.

FIG. 6 is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane 600 is shown as a communications protocol stack between the UE 101 (or alternatively, the UE 102), the RAN node 111 (or alternatively, the RAN node 112), and the MME 121.

The PHY layer 601 may transmit or receive information used by the MAC layer 602 over one or more air interfaces. The PHY layer 601 may further perform link adaptation or adaptive modulation and coding (AMC), power control, cell search (e.g., for initial synchronization and handover purposes), and other measurements used by higher layers, such as the RRC layer 605. The PHY layer 601 may still further perform error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, modulation/demodulation of physical channels, interleaving, rate matching, mapping onto physical channels, and Multiple Input Multiple Output (MIMO) antenna processing.

The MAC layer 602 may perform mapping between logical channels and transport channels, multiplexing of MAC service data units (SDUs) from one or more logical channels onto transport blocks (TB) to be delivered to PHY via transport channels, demultiplexing MAC SDUs to one or more logical channels from transport blocks (TB) delivered from the PHY via transport channels, multiplexing MAC SDUs onto TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), and logical channel prioritization.

The RLC layer 603 may operate in a plurality of modes of operation, including:

Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer 603 may execute transfer of upper layer protocol data units (PDUs), error correction through automatic repeat request (ARQ) for AM data transfers, and

concatenation, segmentation and reassembly of RLC SDUs for UM and AM data transfers. The RLC layer 603 may also execute re-segmentation of RLC data PDUs for AM data transfers, reorder RLC data PDUs for UM and AM data transfers, detect duplicate data for UM and AM data transfers, discard RLC SDUs for UM and AM data transfers, detect protocol errors for AM data transfers, and perform RLC re-establishment.

The PDCP layer 604 may execute header compression and decompression of IP data, maintain PDCP Sequence Numbers (SNs), perform in-sequence delivery of upper layer PDUs at re-establishment of lower layers, eliminate duplicates of lower layer SDUs at re- establishment of lower layers for radio bearers mapped on RLC AM, cipher and decipher control plane data, perform integrity protection and integrity verification of control plane data, control timer-based discard of data, and perform security operations (e.g., ciphering, deciphering, integrity protection, integrity verification, etc.).

The main services and functions of the RRC layer 605 may include broadcast of system information (e.g., included in Master Information Blocks (MIBs) or System Information Blocks (SIBs) related to the non-access stratum (NAS)), broadcast of system information related to the access stratum (AS), paging, establishment, maintenance and release of an RRC connection between the UE and E-UTRAN (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), establishment, configuration, maintenance and release of point to point radio bearers, security functions including key management, inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting. Said MIBs and SIBs may comprise one or more information elements (IEs), which may each comprise individual data fields or data structures.

The UE 101 and the RAN node 111 may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack comprising the PHY layer 601, the MAC layer 602, the RLC layer 603, the PDCP layer 604, and the RRC layer 605.

The non-access stratum (NAS) protocols 606 form the highest stratum of the control plane between the UE 101 and the MME 121. The NAS protocols 606 support the mobility of the UE 101 and the session management procedures to establish and maintain IP connectivity between the UE 101 and the P-GW 123.

The SI Application Protocol (Sl-AP) layer 615 may support the functions of the SI interface and comprise Elementary Procedures (EPs). An EP is a unit of interaction between the RAN node 111 and the CN 120. The S 1-AP layer services may comprise two groups: UE-associated services and non UE-associated services. These services perform functions including, but not limited to: E-UTRAN Radio Access Bearer (E-RAB) management, UE capability indication, mobility, NAS signaling transport, RAN

Information Management (RIM), and configuration transfer.

The Stream Control Transmission Protocol (SCTP) layer (alternatively referred to as the SCTP/IP layer) 614 may ensure reliable delivery of signaling messages between the RAN node 111 and the MME 121 based, in part, on the IP protocol, supported by the IP layer 613. The L2 layer 612 and the LI layer 611 may refer to communication links (e.g., wired or wireless) used by the RAN node 111 and the MME 121 to exchange information.

The RAN node 111 and the MME 121 may utilize an SI -MME interface to exchange control plane data via a protocol stack comprising the LI layer 611, the L2 layer 612, the IP layer 613, the SCTP layer 614, and the Sl-AP layer 615. FIG. 7 illustrates components of a core network in accordance with some embodiments. The components of the CN 120 may be implemented in one physical node or separate physical nodes including components to read and execute instructions from a machine- readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In some embodiments, Network Functions Virtualization (NFV) is utilized to virtualize any or all of the above described network node functions via executable instructions stored in one or more computer-readable storage mediums (described in further detail below). A logical instantiation of the CN 120 may be referred to as a network slice 701, and individual logical instantiations of the CN 120 may provide specific network capabilities and network characteristics. A logical instantiation of a portion of the CN 120 may be referred to as a network sub-slice 702 (e.g., the network sub-slice 702 is shown to include the P-GW 123 and the PCRF 126).

As used herein, the terms "instantiate," "instantiation," and the like may refer to the creation of an instance, and an "instance" may refer to a concrete occurrence of an object, which may occur, for example, during execution of program code. A network instance may refer to information identifying a domain, which may be used for traffic detection and routing in case of different IP domains or overlapping IP addresses. A network slice instance may refer to a set of network functions (NFs) instances and the resources (e.g., compute, storage, and networking resources) required to deploy the network slice.

With respect to 5G systems, a network slice may include the CN control plane and user plane NFs, NG RANs in a serving PLMN, and non-3GPP interworking functions(N3IWF) functions in the serving PLMN. Individual network slices may have different Single Network Slice Selection Assistance Information (S-NSSAI) and/or may have different Slice/Service Types (SSTs). Network slices may differ for supported features and network functions optimizations, and/or multiple network slice instances may deliver the same service/features but for different groups of UEs (e.g., enterprise users). For example, individual network slices may deliver different committed service(s) and/or may be dedicated to a particular customer or enterprise. In this example, each network slice may have different S-NSSAIs with the same SST but with different slice differentiators.

Additionally, a single UE may be served with one or more network slice instances simultaneously via a 5G access node (AN) and associated with eight different S-NSSAIs. Moreover, an action message format (AMF) instance serving an individual UE may belong to each of the network slice instances serving that UE. NFV architectures and infrastructures may be used to virtualize one or more NFs, alternatively performed by proprietary hardware, onto physical resources comprising a combination of industry -standard server hardware, storage hardware, or switches. In other words, NFV systems can be used to execute virtual or reconfigurable implementations of one or more EPC components/functions.

FIG. 8 is a block diagram illustrating components, according to some example embodiments, able to read instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium) and perform any one or more of the methodologies discussed herein. Specifically, FIG. 8 shows a diagrammatic representation of hardware resources 800 including one or more processors (or processor cores) 810, one or more memory /storage devices 820, and one or more communication resources 830, each of which may be communicatively coupled via a bus 840. For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor 802 may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources 800. In some embodiments, the hardware resources 800 may be an element of a CN component, a UE such as UEs 101 or 102, a RAN node such as RAN nodes 111 or 112, or some other device.

The processors 810 (e.g., a central processing unit (CPU), a reduced instruction set computing (RISC) processor, a complex instruction set computing (CISC) processor, a graphics processing unit (GPU), a digital signal processor (DSP) such as a baseband processor, an application specific integrated circuit (ASIC), a radio-frequency integrated circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor 812 and a processor 814.

The memory /storage devices 820 may include main memory, disk storage, or any suitable combination thereof. The memory /storage devices 820 may include, but are not limited to, any type of volatile or non-volatile memory such as dynamic random access memory (DRAM), static random-access memory (SRAM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), Flash memory, solid-state storage, etc.

The communication resources 830 may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices 804 or one or more databases 806 via a network 808. For example, the communication resources 830 may include wired communication components (e.g., for coupling via a Universal Serial Bus (USB)), cellular communication components, NFC components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components.

Instructions 850 may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors 810 to perform any one or more of the methodologies discussed herein. The instructions 850 may reside, completely or partially, within at least one of the processors 810 (e.g., within the processor's cache memory), the memory /storage devices 820, or any suitable combination thereof.

Furthermore, any portion of the instructions 850 may be transferred to the hardware resources 800 from any combination of the peripheral devices 804 or the databases 806. Accordingly, the memory of processors 810, the memory /storage devices 820, the peripheral devices 804, and the databases 806 are examples of computer-readable and machine-readable media.

EXAMPLES

Example 1 may include one or more non-transitory computer readable media comprising instructions that, upon execution of the instructions by one or more processors of a user equipment (UE), are to cause the UE to: transmit, in a UE network capability information element (IE), an indication that the UE supports light connection; identify, from a third generation partnership project (3GPP) network with which the UE is coupled, an indication that the network supports light connection; and enter, based on the indication that the network supports light connection, a light connection mode.

Example 2 may include the one or more non-transitory computer-readable media of example 1, wherein the light connection mode is a radio resource control

(RRC) CONNECTED with a light RRC connection mode or a evolved packet system (EPS) mobility management (EMM)-CONNECTED mode with a light connection.

Example 3 may include the one or more non-transitory computer-readable media of example 1, wherein the light connection mode includes: suspension, by the UE, of signaling radio bearers and data radio bearers; performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 4 may include the one or more non-transitory computer-readable media of any of examples 1-3, wherein the instructions are further to transmit, based on the light connection mode, a ciphered network access stratum (NAS) message to a mobility management entity (MME) of the 3 GPP network.

Example 5 may include the one or more non-transitory computer-readable media of any of examples 1-3, wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 6 may include the one or more non-transitory computer-readable media of any of examples 1-3, wherein the indication that the network supports light connection is based on an identification, by the network, that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 7 may include the one or more non-transitory computer-readable media of any of examples 1-3, wherein the instructions are further to: identify that the UE is to exit the light connection mode; and transmit, via lower layer signal based on the identification that the UE is to exit the light connection mode, an indication that the UE is to exit the light connection mode.

Example 8 may include the one or more non-transitory computer-readable media of example 7, wherein the instructions are further to enter, based on an identification of network acceptance that the UE is to exit the light connection, an EMM-CONNECTED mode.

Example 9 may include the one or more non-transitory computer-readable media of example 7, wherein the instructions are further to enter, UE based on an identification of network rejection that the UE is to exit the light connection, an EMM-IDLE mode.

Example 10 may include the one or more non-transitory computer-readable media of example 7, wherein the lower layer signal is an access stratum (AS) layer signal.

Example 11 may include the one or more non-transitory computer-readable media of example 7, wherein the instructions to identify that the UE is to exit the EMM mode related to light connection include instructions to transmit, by a higher layer entity of the UE to a lower layer entity of the UE, a highPriority Access indication or an emergency indication.

Example 12 may include the one or more non-transitory computer-readable media of example 11, wherein the higher layer entity is a network access stratum (NAS) entity and the lower layer entity is an access stratum (AS) entity. Example 13 may include one or more non-transitory computer-readable media comprising instructions that, when executed by one or more processors of a radio access network (RAN) node of a third generation partnership project (3 GPP) network, are to cause the RAN node to: identify, in a message received from a user equipment (UE) of the 3GPP network, a UE network capability information element (IE) that includes an indication that the UE supports light connection; identify that the network supports light connection; and transmit an indication to the UE that the network supports light connection; wherein the indication that the network supports the light connection is to cause the UE to enter an evolved packet system (EPS) mobility management (EMM) mode related to light connection.

Example 14 may include the one or more non-transitory computer-readable media of example 13, wherein the indication that the network supports light connection is based on identification that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 15 may include the one or more non-transitory computer-readable media of example 13, wherein the EMM mode related to light connection includes: suspension, by the UE, of signaling radio bearers and data radio bearers; performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 16 may include the one or more non-transitory computer-readable media of any of examples 13-15, wherein the instructions are further to: identify a ciphered network access stratum (NAS) message transmitted by the UE; and transmit the ciphered NAS to a mobility management entity (MME) of the 3 GPP network.

Example 17 may include the one or more non-transitory computer-readable media of any of examples 13-15, wherein the EMM mode related to light connection is an EMM- CONNECTED mode with light connection or an EMM LIGHT-CONNECTED mode.

Example 18 may include the one or more non-transitory computer-readable media of any of examples 13-15, wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 19 may include an apparatus to be used in a user equipment (UE) of a third generation partnership project (3 GPP) network, wherein the apparatus comprises: one or more processors; and one or more non-transitory computer-readable media

communicatively coupled with the processors, wherein the one or more non-transitory computer-readable media include instructions that, when executed by the one or more processors, cause the UE to: transmit, in a UE network capability information element (IE), an indication that the UE supports light connection; identify, from the 3GPP network, an indication that the network supports light connection; and enter, based on the indication that the network supports light connection, a light connection mode.

Example 20 may include the apparatus of example 19, wherein the light connection mode is a radio resource control (RRC) CONNECTED with a light RRC connection mode or a evolved packet system (EPS) mobility management (EMM)-CON ECTED mode with a light connection.

Example 21 may include the apparatus of example 19, wherein the light connection mode includes: suspension, by the UE, of signaling radio bearers and data radio bearers;

performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 22 may include the apparatus of any of examples 19-21, wherein the instructions are further to transmit, based on the light connection mode, a ciphered network access stratum (NAS) message to a mobility management entity (MME) of the 3GPP network.

Example 23 may include the apparatus of any of examples 19-21, wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 24 may include the apparatus of any of examples 19-21, wherein the indication that the network supports light connection is based on an identification, by the network, that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 25 may include the apparatus of any of examples 19-21, wherein the instructions are further to: identify that the UE is to exit the light connection mode; and transmit, via lower layer signal based on the identification that the UE is to exit the light connection mode, an indication that the UE is to exit the light connection mode.

Example 26 may include the apparatus of example 25, wherein the instructions are further to enter, based on an identification of network acceptance that the UE is to exit the light connection, an EMM-CONNECTED mode.

Example 27 may include the apparatus of example 25, wherein the instructions are further to enter, UE based on an identification of network rejection that the UE is to exit the light connection, an EMM-IDLE mode.

Example 28 may include the apparatus of example 25, wherein the lower layer signal is an access stratum (AS) layer signal.

Example 29 may include the apparatus of example 25, wherein the instructions to identify that the UE is to exit the EMM mode related to light connection include instructions to transmit, by a higher layer entity of the UE to a lower layer entity of the UE, a highPriority Access indication or an emergency indication.

Example 30 may include the apparatus of example 29, wherein the higher layer entity is a network access stratum (NAS) entity and the lower layer entity is an access stratum (AS) entity.

Example 31 may include an apparatus to be used in a radio access network (RAN) node of a third generation partnership project (3GPP) network, wherein the apparatus comprises: one or more processors; and one or more non-transitory computer-readable media communicatively coupled with the one or more processors, wherein the one or more non- transitory computer-readable media include instructions that, when executed by the one or more processors, are to cause the RAN node to: identify, in a message received from a user equipment (UE) of the 3 GPP network, a UE network capability information element (IE) that includes an indication that the UE supports light connection; identify that the network supports light connection; and transmit an indication to the UE that the network supports light connection; wherein the indication that the network supports the light connection is to cause the UE to enter an evolved packet system (EPS) mobility management (EMM) mode related to light connection.

Example 32 may include the apparatus of example 31, wherein the indication that the network supports light connection is based on identification that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 33 may include the apparatus of example 31, wherein the EMM mode related to light connection includes: suspension, by the UE, of signaling radio bearers and data radio bearers; performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 34 may include the apparatus of any of examples 31-33, wherein the instructions are further to: identify a ciphered network access stratum (NAS) message transmitted by the UE; and transmit the ciphered NAS to a mobility management entity (MME) of the 3 GPP network.

Example 35 may include the apparatus of any of examples 31-33, wherein the EMM mode related to light connection is an EMM-CONNECTED mode with light connection or an EMM LIGHT-CONNECTED mode.

Example 36 may include the apparatus of any of examples 31-33, wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 37 may include a method comprising: transmitting, by a user equipment (UE) in a UE network capability information element (IE), an indication that the UE supports light connection; identifying, by the UE from a third generation partnership project (3 GPP) network with which the UE is coupled, an indication that the network supports light connection; and entering, by the UE based on the indication that the network supports light connection, a light connection mode.

Example 38 may include the method of example 37, wherein the light connection mode is a radio resource control (RRC) CONNECTED with a light RRC connection mode or a evolved packet system (EPS) mobility management (EMM)-CONNECTED mode with a light connection.

Example 39 may include the method of example 37, wherein the light connection mode includes: suspension, by the UE, of signaling radio bearers and data radio bearers;

performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 40 may include the method of any of examples 37-39, further comprising transmitting, by the UE based on the light connection mode, a ciphered network access stratum (NAS) message to a mobility management entity (MME) of the 3GPP network.

Example 41 may include the method of any of examples 37-39, wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 42 may include the method of any of examples 37-39, wherein the indication that the network supports light connection is based on an identification, by the network, that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 43 may include the method of any of examples 37-39, further comprising:

identifying, by the UE, that the UE is to exit the light connection mode; and transmitting, by the UE via lower layer signal based on the identification that the UE is to exit the light connection mode, an indication that the UE is to exit the light connection mode.

Example 44 may include the method of example 43, further comprising entering, by the UE based on an identification of network acceptance that the UE is to exit the light connection, an EMM-CONNECTED mode.

Example 45 may include the method of example 43, further comprising entering, by the UE based on an identification of network rejection that the UE is to exit the light connection, an EMM-IDLE mode.

Example 46 may include the method of example 43, wherein the lower layer signal is an access stratum (AS) layer signal.

Example 47 may include the method of example 43, wherein the identifying that the UE is to exit the EMM mode related to light connection includes transmitting, by a higher layer entity of the UE to a lower layer entity of the UE, a highPriority Access indication or an emergency indication.

Example 48 may include the method of example 47, wherein the higher layer entity is a network access stratum (NAS) entity and the lower layer entity is an access stratum (AS) entity.

Example 49 may include a method comprising: identifying, by a radio access network (RAN) node of a third generation partnership project (3GPP) network in a message received from a user equipment (UE) of the 3GPP network, a UE network capability information element (IE) that includes an indication that the UE supports light connection; identifying, by the RAN node, that the network supports light connection; and

transmitting, by the RAN node, an indication to the UE that the network supports light connection; wherein the indication that the network supports the light connection is to cause the UE to enter an evolved packet system (EPS) mobility management (EMM) mode related to light connection.

Example 50 may include the method of example 49, wherein the indication that the network supports light connection is based on identification that the UE is coupled with a home public land mobile network (HPLMN) or an equivalent HPLMN (eHPLMN).

Example 51 may include the method of example 49, wherein the EMM mode related to light connection includes: suspension, by the UE, of signaling radio bearers and data radio bearers; performance, by the UE, of idle mode procedures; and storing, by the UE, UE access stratum (AS) context information.

Example 52 may include the method of any of examples 49-51, further comprising: identifying, by the RAN node, a ciphered network access stratum (NAS) message transmitted by the UE; and transmitting, by the RAN node, the ciphered NAS to a mobility management entity (MME) of the 3 GPP network.

Example 53 may include the method of any of examples 49-51, wherein the EMM mode related to light connection is an EMM-CONNECTED mode with light connection or an EMM LIGHT-CONNECTED mode.

Example 54 may include the method of any of examples 49-51 , wherein the IE is an IE of an ATTACH REQUEST or a TRACKING AREA UPDATE REQUEST message.

Example 55 may include a user equipment (UE) device that has enhancements and optimizations for features and capabilities relating to Light Connection for connecting to an EPS network or GPRS network. The EPS network may include entities such as eNB, MME, SGW, PGW, SCEF (Service Capability Exposure Function), etc. The GPRS network may include entities such as MS, BS, SGSN, HLR, etc.

Example 56 may include the UE of example 55 or some other example herein, wherein if the UE supports light connection it indicates that to the network in the UE Network capability IE as part of the ATTACH REQUEST and TRACKING AREA UPDATE REQUEST messages. The UE can use light connection only in the home PLMN.

Example 57 may include the network of example 56 or some other example herein, wherein if the network supports light connection and the UE indicates its support for light connection, the network may activate light connection in EMM-CONNECTED mode when user plane radio bearers have been set up. When the UE is roaming to a visited PLMN the network disables the use of light RRC connection.

Example 58 may include the UE of example 57 or some other example herein, wherein if light connection has been activated by the network and if the UE supports light connection then the UE enters a new state EMM-CONNECTED mode with light connection or EMM LIGHT-CONNECTED mode.

Example 59 may include the UE of example 58 or some other example herein that is in EMM-LIGHT-CONNECTED mode. If the UE needs to resume from EMM-LIGHT- CONNECTED mode the UE shall request the lower layer to resume the light connection with RRC establishment cause "High priority access AC 11 - 15", if the UE is to use AC11 - 15 in the selected PLMN or with RRC establishment cause "emergency call" if the UE establishes or modifies a PDN connection for emergency bearer services.

Example 60 may include the UE of example 59 or some other example herein, wherein upon indication from the lower layers that the RRC connection has been resumed when in EMM-CONNECTED mode with light connection, the UE shall enter EMM- CONNECTED mode without light connection. Upon indication from the lower layers that the RRC connection resume has failed due to network rejection when in EMM- CONNECTED mode with light connection, the UE shall enter EMM-IDLE mode.

Example 61 may include the UE of example 58 or some other example herein, wherein in case of fallback to RRC connection establishment during resume from EMM-LIGHT- CONNECTED mode, legacy behaviour is applicable. When a UE in light RRC connection receives the RRCConnectionSetup message in response to

RRCConnectionResumeRequest, the UE access stratum informs the UE NAS that the RRC connection resume has been fallbacked, and UE AS discards UE AS context and resumeldentity.

Example 62 may include the UE of example 58 or some other example herein, wherein the UE is in EMM-LIGHT-CONNECTED mode and is camped on its home PLMN

(HPLMN) or equivalent home PLMN (EHPLMN), the UE shall perform high priority PLMN selection, similar to that in UTRAN RRC connected mode as specified in

3 GPP TS 23.122.

Example 63 may include an apparatus comprising means to perform one or more elements of a method described in or related to any of examples 1-62, or any other method or process described herein.

Example 64 may include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 1-62, or any other method or process described herein.

Example 65 may include an apparatus comprising logic, modules, or circuitry to perform one or more elements of a method described in or related to any of examples 1-62, or any other method or process described herein.

Example 66 may include a method, technique, or process as described in or related to any of examples 1-62, or portions or parts thereof.

Example 67 may include an apparatus comprising: one or more processors and one or more computer readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform the method, techniques, or process as described in or related to any of examples 1-62, or portions thereof.

Example 68 may include a method of communicating in a wireless network as shown and described herein.

Example 69 may include a system for providing wireless communication as shown and described herein.

Example 70 may include a device for providing wireless communication as shown and described herein.

The description herein of illustrated implementations, including what is described in the Abstract, is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. While specific implementations and examples are described herein for illustrative purposes, a variety of alternate or equivalent embodiments or implementations calculated to achieve the same purposes may be made in light of the above detailed description, without departing from the scope of the present disclosure, as those skilled in the relevant art will recognize.