PATENT DOCUMENT

Publication Number: US-11778529-B2
Application Number: US-201917288394-A
Country: US
Kind Code: B2

Title: Robust header compression indication after path switch during handover

Abstract:
Systems, methods, and devices are provided to: perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; perform PDCP reordering of the deciphered packets in the common buffer to generated a stream or reordered packets; perform robust header compression (ROHC) decompression on the stream of reordered packets; and determine, based on a packet indication, to reset the ROHC decompression, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during a handover from a source cell to a target cell.

Claims:
The invention claimed is: 
     
       1. An apparatus for a user equipment (UE) configured to perform a handover from a source cell to a target cell in a wireless network, the apparatus comprising:
 a memory interface to send or receive, to or from a memory device, packets received from the source cell and the target cell; and 
 a processor to: 
 perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; 
 perform PDCP reordering of the deciphered packets in the common buffer to generate a stream of reordered packets; 
 perform robust header compression (ROHC) decompression on the stream of reordered packets; and 
 determine, based on a packet indication, to reset the ROHC decompression, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during the handover from the source cell to the target cell. 
 
     
     
       2. The apparatus of  claim 1 , wherein the PDCP header corresponds to a PDCP data protocol data unit (PDU) carry data from a data radio bearer (DRB). 
     
     
       3. The apparatus of  claim 2 , wherein the PDCP data PDU corresponds to one of the packets received from the target cell. 
     
     
       4. The apparatus of  claim 1 , wherein the packet indication comprises a PDCP control protocol data unit (PDU) configured to indicate the start of ROHC reset. 
     
     
       5. The apparatus of  claim 4 , wherein the processor is further configured to perform physical (PHY) layer, media access control (MAC) layer, and radio link control (RLC) layer processes simultaneously on both a first set of packets received from the source cell and a second set of packets received from the target cell. 
     
     
       6. The apparatus of  claim 5 , wherein the processor is further configured to perform an integrity protection check for control plane packets received from at least one of the source cell and the target cell. 
     
     
       7. A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a processor of a user equipment, cause the processor to:
 process packets received from a source cell and a target cell; 
 perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; 
 perform PDCP reordering of the deciphered packets in the common buffer to generate a stream of reordered packets; 
 perform robust header compression (ROHC) decompression on the stream of reordered packets; and 
 determine, based on a packet indication, to reset the ROHC decompression, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during handover from the source cell to the target cell. 
 
     
     
       8. The computer-readable storage medium of  claim 7 , wherein the PDCP header corresponds to a PDCP data protocol data unit (PDU) carry data from a data radio bearer (DRB). 
     
     
       9. The computer-readable storage medium of  claim 8 , wherein the PDCP data PDU corresponds to one of the packets received from the target cell. 
     
     
       10. The computer-readable storage medium of  claim 7 , wherein the packet indication comprises a PDCP control protocol data unit (PDU) configured to indicate the start of ROHC reset. 
     
     
       11. The computer-readable storage medium of  claim 10 , wherein to process the packets received from the source cell and the target cell comprises to perform physical (PHY) layer, media access control (MAC) layer, and radio link control (RLC) layer processes simultaneously on both a first set of packets received from the source cell and a second set of packets received from the target cell. 
     
     
       12. The computer-readable storage medium of  claim 11 , wherein the instructions further configure the processor to perform an integrity protection check for control plane packets received from at least one of the source cell and the target cell. 
     
     
       13. A non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a processor of a target cell in a wireless communication system, cause the processor to:
 receive partial packet data convergence protocol (PDCP) protocol data units (PDUs) from a source cell in the wireless communication system, the partial PDCP PDUs comprising robust header compression (ROHC) by the source cell; 
 perform PDCP ciphering on the partial PDCP PDUs to generate ciphered PDCP PDUs; 
 send the ciphered PDCP PDUs to a user equipment (UE); and 
 after release of the source cell to complete a path switch to the target cell: 
 perform ROHC on data received from a core network of the wireless communication system; and 
 generate a packet to indicate a start of a ROHC reset to the UE, wherein the packet to indicate the start of the ROHC reset comprises a single bit in a PDCP header set to indicate the start of the ROHC reset. 
 
     
     
       14. The computer-readable storage medium of  claim 13 , wherein the packet to indicate the start of the ROHC reset comprises a PDCP control PDU configured to indicate the start of the ROHC reset. 
     
     
       15. The computer-readable storage medium of  claim 14 , wherein the instructions further configure the processor to perform integrity protection for control plane data of the partial PDCP PDUs.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a national stage filing under 35 U.S.C. § 371 of International Patent Application No. PCT/US2019/057868, filed Oct. 24, 2019, which claims the benefit of U.S. Provisional Patent Application No. 62/753,731, filed Oct. 31, 2018, each of which is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     This application relates generally to wireless communication systems, and more specifically to simultaneous connectivity handover. 
     BACKGROUND 
     Wireless mobile communication technology uses various standards and protocols to transmit data between a base station and a wireless mobile device. Wireless communication system standards and protocols can include the 3rd Generation Partnership Project (3GPP) long term evolution (LTE); the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard, which is commonly known to industry groups as worldwide interoperability for microwave access (WiMAX); and the IEEE 802.11 standard for wireless local area networks (WLAN), which is commonly known to industry groups as Wi-Fi. In 3GPP radio access networks (RANs) in LTE systems, the base station can include a RAN Node such as a Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (also commonly denoted as evolved Node B, enhanced Node B, eNodeB, or eNB) and/or Radio Network Controller (RNC) in an E-UTRAN, which communicate with a wireless communication device, known as user equipment (UE). In fifth generation (5G) wireless RANs, RAN Nodes can include a 5G Node, new radio (NR) node or g Node B (gNB). 
     RANs use a radio access technology (RAT) to communicate between the RAN Node and UE. RANs can include global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE) RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), and/or E-UTRAN, which provide access to communication services through a core network. Each of the RANs operates according to a specific 3GPP RAT. For example, the GERAN implements GSM and/or EDGE RAT, the UTRAN implements universal mobile telecommunication system (UMTS) RAT or other 3GPP RAT, and the E-UTRAN implements LTE RAT. 
     A core network can be connected to the UE through the RAN Node. The core network can include a serving gateway (SGW), a packet data network (PDN) gateway (PGW), an access network detection and selection function (ANDSF) server, an enhanced packet data gateway (ePDG) and/or a mobility management entity (MME). 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    illustrates protocol stacks in accordance with one embodiment. 
         FIG.  2    illustrates security and reordering handling in accordance with one embodiment. 
         FIG.  3    illustrates a PDCP packet format in accordance with one embodiment. 
         FIG.  4    illustrates a method in accordance with one embodiment. 
         FIG.  5    illustrates a method in accordance with another embodiment. 
         FIG.  6    illustrates a system in accordance with one embodiment. 
         FIG.  7    illustrates a device in accordance with one embodiment. 
         FIG.  8    illustrates example interfaces in accordance with one embodiment. 
         FIG.  9    illustrates a control plane in accordance with one embodiment. 
         FIG.  10    illustrates a user plane in accordance with one embodiment. 
         FIG.  11    illustrates components in accordance with one embodiment. 
         FIG.  12    illustrates a system in accordance with one embodiment. 
         FIG.  13    illustrates components in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Simultaneous connectivity handover may achieve a goal of 0 millisecond (ms) interruption time both in LTE and NR. One of the architecture options is a non-split bearer. This option may be the same as or similar to that used in enhanced mobile broadband (eMBB). If the non-split bearer architecture is considered, a UE may receive two streams of data (one from a source cell (which may include a serving cell) and one from a target cell during handover (HO). 
     For example,  FIG.  1    illustrates protocol stacks  100  for a non-split bearer architecture to support simultaneous connectivity handover according to certain embodiments. In particular,  FIG.  1    shows a protocol stack for a serving cell including a physical layer (shown as PHY  102 ), a media access control (MAC) layer (shown as MAC  104 ), a radio link control (RLC) layer (shown as RLC  106 ), and a packet data convergence protocol (PDCP) layer (shown as PDCP  108 ). Similarly, a protocol stack for a target cell includes a PHY  110 , a MAC  112 , an RLC  114 , and a PDCP  116 . 
     Before the handover, the UE may connect only to the source (serving) cell. The UE may communicate with the source cell using a first protocol stack including a PHY  118 , a MAC  120 , an RLC  122 , and a PDCP  124 . The UE may be configured to receive a handover command that enables simultaneously connection during handover. Therefore, the UE may have prepared a second protocol stack including a PHY  126 , a MAC  128 , an RLC  130 , and a PDCP  132  to use for communication with the target cell once the UE receives the handover command. During handover, the UE may have completed a random access channel (RACH) procedure with the target cell. Thus, during handover, the UE may be connected with both source cell and target cell. 
     As shown in  FIG.  1   , during handover, the source (serving) cell may forward data to the target cell, which the target cell may process and send to the UE. The data forwarded from the source cell to the serving cell may include a partial PDCP protocol data units (PDU) with robust header compression (ROHC) and sequence number (SN). The UE may perform PDCP reordering  134  of PDUs received from both the source cell and the target cell in the same buffer. However, after the path switch is complete from the source cell to the target cell, ROHC decompression by the UE may no longer work because the source cell had initiated and was performing the ROHC compression for packets received from the source cell and the target cell. After the path switch, the target cell performs the ROHC compression for the packets sent to the UE. Thus, the ROHC decompression needs to be reset at the UE  208 . 
       FIG.  2    illustrates security and reordering handling  200  for a non-split bearer architecture according to certain embodiments. In particular,  FIG.  2    shows an example of downlink (DL) user plane handover for the non-split bearer architecture. 
     On the network side, a serving gateway (shown as SGW  202 ) sends data (shown as data 1, 2, 3, and 4) to a source cell  204 . The source cell  204  processes ROHC, if needed, and allocates PDCP SN for each packet. The source cell  204  then forwards the partial PDCP PDU (after ROHC) and the SN to a target cell  206 . In addition, or alternatively, the source cell  204  processes integrity protection (for control plane (c-plane) data and performs ciphering before sending at least some of the data to a UE  208 . 
     A PDCP entity of the target cell  206  may only perform integrity protection (for c-plane data) and ciphering on the partial PDCP PDU received from the source cell  204  before sending it to the UE  208 . 
     At the UE receiver side (e.g., after the UE  208  determines a count of the PDCP PDU), the UE  208  may perform separate operations for each link to the source cell  204  and the target cell  206 . For data received through the link to the source cell  204 , the UE  208  performs PHY/MAC/RLC processing  210  (e.g., as in legacy LTE procedures), performs an integrity protection check (for c-plane data) and PDCP deciphering  212 , and stores the packets in a common buffer  214  for reordering. Similarly, for data received through the link to the target cell  206 , the UE  208  performs PHY/MAC/RLC processing  216 , performs an integrity protection check (for c-plane data) and PDCP deciphering  218 , and stores the packets in the common buffer  214  for reordering. 
     After the UE  208  performs PDCP reordering off the packets in the common buffer  214 , the UE  208  performs ROHC decompression  220  and sends  222  the data to a higher layer. 
     After the path switch, ROHC decompression  220  may not work and may need to be reset. For example, ROHC may include a progressive compression wherein decompression of subsequent packets may depend on earlier packets. Thus, once the ROHC is switched from being performed by the source cell  204  to being performed by the target cell  206 , the UE  208  may no longer be able to use information received in earlier packets to decompress current packets. However, legacy implementations do not provide a way to indicate to the UE which packet can start ROHC reset. 
     Thus, certain embodiments herein provide a ROHC reset indication after the path switch during handover. 
     For example, one embodiment provides a single bit (1-bit) indication in a PDCP header to indicate ROHC reset.  FIG.  3    illustrates a PDCP packet format  300  according to one embodiment wherein a reserve bit may be configured as a ROHC reset indicator  302 . When the ROHC reset indicator  302  is set, it indicates to the UE that the packet can be used to start ROHC reset.  FIG.  3    shows the format of the PDCP data PDU when a 12 bit SN length is used. This format is applicable for PDCP data PDUs carrying data from data radio bearers (DRBs) mapped on RLC AM (acknowledge mode) or RLC UM (unacknowledged mode). 
     In another embodiment, a new PDCP control PDU may be created to indicate when the ROHC should be reset/initialized. 
       FIG.  4    illustrates a method  400  for a UE to perform a handover from a source cell to a target cell in a wireless network according to one embodiment. In block  402 , the method  400  processes packets received from the source cell and the target cell. In block  404 , the method  400  performs packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer. In block  406 , the method  400  performs PDCP reordering of the deciphered packets in the common buffer to generate a stream of reordered packets. In block  408 , the method  400  performs robust header compression (ROHC) decompression on the stream of reordered packets. In block  410 , the method  400  determines, based on a packet indication, to reset the ROHC decompression. 
     In one embodiment, the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during the handover from the source cell to the target cell. The PDCP header may correspond to a PDCP data PDU carrying data from a DRB. The PDCP data PDU may correspond to one of the packets received from the target cell. 
     In another embodiment, the packet indication comprises a PDCP control PDU configured to indicate a start of ROHC reset. 
       FIG.  5    illustrates a method  500  for a target cell for handover of a UE in a wireless communication system. In block  502 , the method  500  receives partial packet data convergence protocol (PDCP) protocol data units (PDUs) from a source cell in the wireless communication system, the partial PDCP PDUs comprising robust header compression (ROHC) by the source cell. In block  504 , the method  500  performs PDCP ciphering on the partial PDCP PDUs to generate ciphered PDCP PDUs. In block  506 , the method  500  sends the ciphered PDCP PDUs to the UE. After release of the source cell to complete a path switch to the target cell in block  508 , in block  510  the method  500  performs ROHC on data received from a core network of the wireless communication system, and in block  512  the method  500  generates a packet to indicate a start of a ROHC reset to the UE. 
     In one embodiment, the packet to indicate the start of the ROHC reset comprises a single bit in a PDCP header set to indicate the start of the ROHC reset. 
     In another embodiment, the packet to indicate the start of the ROHC reset comprises a PDCP control PDU configured to indicate the start of the ROHC reset. 
     Example Systems and Apparatuses 
       FIG.  6    illustrates an architecture of a system  600  of a network in accordance with some embodiments. The system  600  is shown to include a UE  602 ; a 5G access node or RAN node (shown as (R)AN node  608 ); a User Plane Function (shown as UPF  604 ); a Data Network (DN  606 ), which may be, for example, operator services, Internet access or 3rd party services; and a 5G core network (5GC) (shown as CN  610 ). 
     The CN  610  may include an Authentication Server Function (AUSF  614 ); a Core Access and Mobility Management Function (AMF  612 ); a Session Management Function (SMF  618 ); a Network Exposure Function (NEF  616 ); a Policy Control Function (PCF  622 ); a Network Function (NF) Repository Function (NRF  620 ); a Unified Data Management (UDM  624 ); and an Application Function (AF  626 ). The CN  610  may also include other elements that are not shown, such as a Structured Data Storage network function (SDSF), an Unstructured Data Storage network function (UDSF), and the like. 
     The UPF  604  may act as an anchor point for intra-RAT and inter-RAT mobility, an external PDU session point of interconnect to DN  606 , and a branching point to support multi-homed PDU session. The UPF  604  may also perform packet routing and forwarding, packet inspection, enforce user plane part of policy rules, lawfully intercept packets (UP collection); traffic usage reporting, perform QoS handling for user plane (e.g. Packet filtering, gating, UL/DL rate enforcement), perform Uplink Traffic verification (e.g., SDF to QoS flow mapping), transport level packet marking in the uplink and downlink, and downlink packet buffering and downlink data notification triggering. UPF  604  may include an uplink classifier to support routing traffic flows to a data network. The DN  606  may represent various network operator services, Internet access, or third party services. 
     The AUSF  614  may store data for authentication of UE  602  and handle authentication related functionality. The AUSF  614  may facilitate a common authentication framework for various access types. 
     The AMF  612  may be responsible for registration management (e.g., for registering UE  602 , etc.), connection management, reachability management, mobility management, and lawful interception of AMF-related events, and access authentication and authorization. AMF  612  may provide transport for SM messages for the SMF  618 , and act as a transparent proxy for routing SM messages. AMF  612  may also provide transport for short message service (SMS) messages between UE  602  and an SMS function (SMSF) (not shown by  FIG.  6   ). AMF  612  may act as Security Anchor Function (SEA), which may include interaction with the AUSF  614  and the UE  602 , receipt of an intermediate key that was established as a result of the UE  602  authentication process. Where USIM based authentication is used, the AMF  612  may retrieve the security material from the AUSF  614 . AMF  612  may also include a Security Context Management (SCM) function, which receives a key from the SEA that it uses to derive access-network specific keys. Furthermore, AMF  612  may be a termination point of RAN CP interface (N2 reference point), a termination point of NAS (NI) signaling, and perform NAS ciphering and integrity protection. 
     AMF  612  may also support NAS signaling with a UE  602  over an N3 interworking-function (IWF) interface. The N3IWF may be used to provide access to untrusted entities. N3IWF may be a termination point for the N2 and N3 interfaces for control plane and user plane, respectively, and as such, may handle N2 signaling from SMF and AMF for PDU sessions and QoS, encapsulate/de-encapsulate packets for IPSec and N3 tunneling, mark N3 user-plane packets in the uplink, and enforce QoS corresponding to N3 packet marking taking into account QoS requirements associated to such marking received over N2. N3IWF may also relay uplink and downlink control-plane NAS (NI) signaling between the UE  602  and AMF  612 , and relay uplink and downlink user-plane packets between the UE  602  and UPF  604 . The N3IWF also provides mechanisms for IPsec tunnel establishment with the UE  602 . 
     The SMF  618  may be responsible for session management (e.g., session establishment, modify and release, including tunnel maintain between UPF and AN node); UE IP address allocation &amp; management (including optional Authorization); Selection and control of UP function; Configures traffic steering at UPF to route traffic to proper destination; termination of interfaces towards Policy control functions; control part of policy enforcement and QoS; lawful intercept (for SM events and interface to LI System); termination of SM parts of NAS messages; downlink Data Notification; initiator of AN specific SM information, sent via AMF over N2 to AN; determine SSC mode of a session. The SMF  618  may include the following roaming functionality: handle local enforcement to apply QoS SLAB (VPLMN); charging data collection and charging interface (VPLMN); lawful intercept (in VPLMN for SM events and interface to LI System); support for interaction with external DN for transport of signaling for PDU session authorization/authentication by external DN. 
     The NEF  616  may provide means for securely exposing the services and capabilities provided by 3GPP network functions for third party, internal exposure/re-exposure, Application Functions (e.g., AF  626 ), edge computing or fog computing systems, etc. In such embodiments, the NEF  616  may authenticate, authorize, and/or throttle the AFs. NEF  616  may also translate information exchanged with the AF  626  and information exchanged with internal network functions. For example, the NEF  616  may translate between an AF-Service-Identifier and an internal 5GC information. NEF  616  may also receive information from other network functions (NFs) based on exposed capabilities of other network functions. This information may be stored at the NEF  616  as structured data, or at a data storage NF using a standardized interfaces. The stored information can then be re-exposed by the NEF  616  to other NFs and AFs, and/or used for other purposes such as analytics. 
     The NRF  620  may support service discovery functions, receive NF Discovery Requests from NF instances, and provide the information of the discovered NF instances to the NF instances. NRF  620  also maintains information of available NF instances and their supported services. 
     The PCF  622  may provide policy rules to control plane function(s) to enforce them, and may also support unified policy framework to govern network behavior. The PCF  622  may also implement a front end (FE) to access subscription information relevant for policy decisions in a UDR of UDM  624 . 
     The UDM  624  may handle subscription-related information to support the network entities&#39; handling of communication sessions, and may store subscription data of UE  602 . The UDM  624  may include two parts, an application FE and a User Data Repository (UDR). The UDM may include a UDM FE, which is in charge of processing of credentials, location management, subscription management and so on. Several different front ends may serve the same user in different transactions. The UDM-FE accesses subscription information stored in the UDR and performs authentication credential processing; user identification handling; access authorization; registration/mobility management; and subscription management. The UDR may interact with PCF  622 . UDM  624  may also support SMS management, wherein an SMS-FE implements the similar application logic as discussed previously. 
     The AF  626  may provide application influence on traffic routing, access to the Network Capability Exposure (NCE), and interact with the policy framework for policy control. The NCE may be a mechanism that allows the 5GC and AF  626  to provide information to each other via NEF  616 , which may be used for edge computing implementations. In such implementations, the network operator and third party services may be hosted close to the UE  602  access point of attachment to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. For edge computing implementations, the 5GC may select a UPF  604  close to the UE  602  and execute traffic steering from the UPF  604  to DN  606  via the N6 interface. This may be based on the UE subscription data, UE location, and information provided by the AF  626 . In this way, the AF  626  may influence UPF (re)selection and traffic routing. Based on operator deployment, when AF  626  is considered to be a trusted entity, the network operator may permit AF  626  to interact directly with relevant NFs. 
     As discussed previously, the CN  610  may include an SMSF, which may be responsible for SMS subscription checking and verification, and relaying SM messages to/from the UE  602  to/from other entities, such as an SMS-GMSC/IWMSC/SMS-router. The SMS may also interact with AMF  612  and UDM  624  for notification procedure that the UE  602  is available for SMS transfer (e.g., set a UE not reachable flag, and notifying UDM  624  when UE  602  is available for SMS). 
     The system  600  may include the following service-based interfaces: Namf: Service-based interface exhibited by AMF; Nsmf: Service-based interface exhibited by SMF; Nnef: Service-based interface exhibited by NEF; Npcf: Service-based interface exhibited by PCF; Nudm: Service-based interface exhibited by UDM; Naf: Service-based interface exhibited by AF; Nnrf: Service-based interface exhibited by NRF; and Nausf: Service-based interface exhibited by AUSF. 
     The system  600  may include the following reference points: N1: Reference point between the UE and the AMF; N2: Reference point between the (R)AN and the AMF; N3: Reference point between the (R)AN and the UPF; N4: Reference point between the SMF and the UPF; and N6: Reference point between the UPF and a Data Network. There may be many more reference points and/or service-based interfaces between the NF services in the NFs, however, these interfaces and reference points have been omitted for clarity. For example, an NS reference point may be between the PCF and the AF; an N7 reference point may be between the PCF and the SMF; an N11 reference point between the AMF and SMF; etc. In some embodiments, the CN  610  may include an Nx interface, which is an inter-CN interface between the MME (e.g., MME(s)  928 ) and the AMF  612  in order to enable interworking between CN  610  and CN  1106 . 
     Although not shown by  FIG.  6   , the system  600  may include multiple RAN nodes (such as (R)AN node  608 ) wherein an Xn interface is defined between two or more (R)AN node  608  (e.g., gNBs and the like) connecting to CN  610 , between a (R)AN node  608  (e.g., gNB) connecting to CN  610  and an eNB, and/or between two eNBs connecting to CN  610 . 
     In some implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non-guaranteed delivery of user plane PDUs and support/provide data forwarding and flow control functionality. The Xn-C may provide management and error handling functionality, functionality to manage the Xn-C interface; mobility support for UE  602  in a connected mode (e.g., CM-CONNECTED) including functionality to manage the UE mobility for connected mode between one or more (R)AN node  608 . The mobility support may include context transfer from an old (source) serving (R)AN node  608  to new (target) serving (R)AN node  608 ; and control of user plane tunnels between old (source) serving (R)AN node  608  to new (target) serving (R)AN node  608 . 
     A protocol stack of the Xn-U may include a transport network layer built on Internet Protocol (IP) transport layer, and a GTP-U layer on top of a UDP and/or IP layer(s) to carry user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol (referred to as Xn Application Protocol (Xn-AP)) and a transport network layer that is built on an SCTP layer. The SCTP layer may be on top of an IP layer. The SCTP layer provides the guaranteed delivery of application layer messages. In the transport IP layer point-to-point transmission is used to deliver the signaling PDUs. In other implementations, the Xn-U protocol stack and/or the Xn-C protocol stack may be same or similar to the user plane and/or control plane protocol stack(s) shown and described herein. 
       FIG.  7    illustrates example components of a device  700  in accordance with some embodiments. In some embodiments, the device  700  may include application circuitry  702 , baseband circuitry  704 , Radio Frequency (RF) circuitry (shown as RF circuitry  720 ), front-end module (FEM) circuitry (shown as FEM circuitry  730 ), one or more antennas  732 , and power management circuitry (PMC) (shown as PMC  734 ) coupled together at least as shown. The components of the illustrated device  700  may be included in a UE or a RAN node. In some embodiments, the device  700  may include fewer elements (e.g., a RAN node may not utilize application circuitry  702 , and instead include a processor/controller to process IP data received from an EPC). In some embodiments, the device  700  may include additional elements such as, for example, memory/storage, display, camera, sensor, or input/output (I/O) interface. In other embodiments, the components described below may be included in more than one device (e.g., said circuitries may be separately included in more than one device for Cloud-RAN (C-RAN) implementations). 
     The application circuitry  702  may include one or more application processors. For example, the application circuitry  702  may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications or operating systems to run on the device  700 . In some embodiments, processors of application circuitry  702  may process IP data packets received from an EPC. 
     The baseband circuitry  704  may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry  704  may include one or more baseband processors or control logic to process baseband signals received from a receive signal path of the RF circuitry  720  and to generate baseband signals for a transmit signal path of the RF circuitry  720 . The baseband circuitry  704  may interface with the application circuitry  702  for generation and processing of the baseband signals and for controlling operations of the RF circuitry  720 . For example, in some embodiments, the baseband circuitry  704  may include a third generation (3G) baseband processor (3G baseband processor  706 ), a fourth generation (4G) baseband processor (4G baseband processor  708 ), a fifth generation (5G) baseband processor (5G baseband processor  710 ), or other baseband processor(s)  712  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  704  (e.g., one or more of baseband processors) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry  720 . In other embodiments, some or all of the functionality of the illustrated baseband processors may be included in modules stored in the memory  718  and executed via a Central Processing Unit (CPU  714 ). 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  704  may include Fast-Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry  704  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  704  may include a digital signal processor (DSP), such as one or more audio DSP(s)  716 . The one or more audio DSP(s)  716  may include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry 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  704  and the application circuitry  702  may be implemented together such as, for example, on a system on a chip (SOC). 
     In some embodiments, the baseband circuitry  704  may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry  704  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  704  is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry. 
     The RF circuitry  720  may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry  720  may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. The RF circuitry  720  may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry  730  and provide baseband signals to the baseband circuitry  704 . The RF circuitry  720  may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry  704  and provide RF output signals to the FEM circuitry  730  for transmission. 
     In some embodiments, the receive signal path of the RF circuitry  720  may include mixer circuitry  722 , amplifier circuitry  724  and filter circuitry  726 . In some embodiments, the transmit signal path of the RF circuitry  720  may include filter circuitry  726  and mixer circuitry  722 . The RF circuitry  720  may also include synthesizer circuitry  728  for synthesizing a frequency for use by the mixer circuitry  722  of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry  722  of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry  730  based on the synthesized frequency provided by synthesizer circuitry  728 . The amplifier circuitry  724  may be configured to amplify the down-converted signals and the filter circuitry  726  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  704  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, the mixer circuitry  722  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  722  of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry  728  to generate RF output signals for the FEM circuitry  730 . The baseband signals may be provided by the baseband circuitry  704  and may be filtered by the filter circuitry  726 . 
     In some embodiments, the mixer circuitry  722  of the receive signal path and the mixer circuitry  722  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  722  of the receive signal path and the mixer circuitry  722  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  722  of the receive signal path and the mixer circuitry  722  may be arranged for direct downconversion and direct upconversion, respectively. In some embodiments, the mixer circuitry  722  of the receive signal path and the mixer circuitry  722  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  720  may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry  704  may include a digital baseband interface to communicate with the RF circuitry  720 . 
     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  728  may be a fractional-N synthesizer or a fractional N/N+1 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  728  may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. 
     The synthesizer circuitry  728  may be configured to synthesize an output frequency for use by the mixer circuitry  722  of the RF circuitry  720  based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry  728  may be a fractional N/N+1 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  704  or the application circuitry  702  (such as an 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 application circuitry  702 . 
     Synthesizer circuitry  728  of the RF circuitry  720  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 (DPA). 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, the synthesizer circuitry  728  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  720  may include an IQ/polar converter. 
     The FEM circuitry  730  may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas  732 , amplify the received signals and provide the amplified versions of the received signals to the RF circuitry  720  for further processing. The FEM circuitry  730  may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry  720  for transmission by one or more of the one or more antennas  732 . In various embodiments, the amplification through the transmit or receive signal paths may be done solely in the RF circuitry  720 , solely in the FEM circuitry  730 , or in both the RF circuitry  720  and the FEM circuitry  730 . 
     In some embodiments, the FEM circuitry  730  may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry  730  may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry  730  may include an LNA to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry  720 ). The transmit signal path of the FEM circuitry  730  may include a power amplifier (PA) to amplify input RF signals (e.g., provided by the RF circuitry  720 ), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas  732 ). 
     In some embodiments, the PMC  734  may manage power provided to the baseband circuitry  704 . In particular, the PMC  734  may control power-source selection, voltage scaling, battery charging, or DC-to-DC conversion. The PMC  734  may often be included when the device  700  is capable of being powered by a battery, for example, when the device  700  is included in a UE. The PMC  734  may increase the power conversion efficiency while providing desirable implementation size and heat dissipation characteristics. 
       FIG.  7    shows the PMC  734  coupled only with the baseband circuitry  704 . However, in other embodiments, the PMC  734  may be additionally or alternatively coupled with, and perform similar power management operations for, other components such as, but not limited to, the application circuitry  702 , the RF circuitry  720 , or the FEM circuitry  730 . 
     In some embodiments, the PMC  734  may control, or otherwise be part of, various power saving mechanisms of the device  700 . For example, if the device  700  is in an RRC_Connected state, where it is still connected to the RAN node as it expects to receive traffic shortly, then it may enter a state known as Discontinuous Reception Mode (DRX) after a period of inactivity. During this state, the device  700  may power down for brief intervals of time and thus save power. 
     If there is no data traffic activity for an extended period of time, then the device  700  may transition off to an RRC_Idle state, where it disconnects from the network and does not perform operations such as channel quality feedback, handover, etc. The device  700  goes into a very low power state and it performs paging where again it periodically wakes up to listen to the network and then powers down again. The device  700  may not receive data in this state, and in order to receive data, it transitions back to an RRC_Connected state. 
     An additional power saving mode may allow a device to be unavailable to the network for periods longer than a paging interval (ranging from seconds to a few hours). During this time, the device is totally unreachable to the network and may power down completely. Any data sent during this time incurs a large delay and it is assumed the delay is acceptable. 
     Processors of the application circuitry  702  and processors of the baseband circuitry  704  may be used to execute elements of one or more instances of a protocol stack. For example, processors of the baseband circuitry  704 , alone or in combination, may be used to execute Layer  3 , Layer  2 , or Layer  1  functionality, while processors of the application circuitry  702  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.  8    illustrates example interfaces  800  of baseband circuitry in accordance with some embodiments. As discussed above, the baseband circuitry  704  of  FIG.  7    may comprise 3G baseband processor  706 , 4G baseband processor  708 , 5G baseband processor  710 , other baseband processor(s)  712 , CPU  714 , and a memory  718  utilized by said processors. As illustrated, each of the processors may include a respective memory interface  802  to send/receive data to/from the memory  718 . 
     The baseband circuitry  704  may further include one or more interfaces to communicatively couple to other circuitries/devices, such as a memory interface  804  (e.g., an interface to send/receive data to/from memory external to the baseband circuitry  704 ), an application circuitry interface  806  (e.g., an interface to send/receive data to/from the application circuitry  702  of  FIG.  7   ), an RF circuitry interface  808  (e.g., an interface to send/receive data to/from RF circuitry  720  of  FIG.  7   ), a wireless hardware connectivity interface  810  (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  812  (e.g., an interface to send/receive power or control signals to/from the PMC  734 . 
       FIG.  9    is an illustration of a control plane protocol stack in accordance with some embodiments. In this embodiment, a control plane  900  is shown as a communications protocol stack between the UE  902 , the RAN  908 , and the MME(s)  928 . 
     A PHY layer  904  may transmit or receive information used by the MAC layer  906  over one or more air interfaces. The PHY layer  904  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 an RRC layer  914 . The PHY layer  904  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  906  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, de-multiplexing 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 (HARD), and logical channel prioritization. 
     An RLC layer  910  may operate in a plurality of modes of operation, including: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The RLC layer  910  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  910  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. 
     A PDCP layer  912  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  914  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  902  and the RAN  908  may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data via a protocol stack comprising the PHY layer  904 , the MAC layer  906 , the RLC layer  910 , the PDCP layer  912 , and the RRC layer  914 . 
     In the embodiment shown, the non-access stratum (NAS) protocols (NAS protocols  916 ) form the highest stratum of the control plane between the UE  902  and the MME(s)  928 . The NAS protocols  916  support the mobility of the UE  902  and the session management procedures to establish and maintain IP connectivity between the UE  902  and the P-GW  1008 . 
     The S1 Application Protocol (S1-AP) layer (S1-AP layer  926 ) may support the functions of the S1 interface and comprise Elementary Procedures (EPs). An EP is a unit of interaction between the RAN  908  and the CN  1106 . The S1-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 stream control transmission protocol/internet protocol (SCTP/IP) layer) (SCTP layer  924 ) may ensure reliable delivery of signaling messages between the RAN  908  and the MME(s)  928  based, in part, on the IP protocol, supported by an IP layer  922 . An L2 layer  920  and an L1 layer  918  may refer to communication links (e.g., wired or wireless) used by the RAN node and the MME to exchange information. 
     The RAN  908  and the MME(s)  928  may utilize an S1-MME interface to exchange control plane data via a protocol stack comprising the L1 layer  918 , the L2 layer  920 , the IP layer  922 , the SCTP layer  924 , and the S1-AP layer  926 . 
       FIG.  10    is an illustration of a user plane protocol stack in accordance with some embodiments. In this embodiment, a user plane  1000  is shown as a communications protocol stack between the UE  902 , the RAN  908 , the S-GW  1006 , and the P-GW  1008 . The user plane  1000  may utilize at least some of the same protocol layers as the control plane  900 . For example, the UE  902  and the RAN  908  may utilize a Uu interface (e.g., an LTE-Uu interface) to exchange user plane data via a protocol stack comprising the PHY layer  904 , the MAC layer  906 , the RLC layer  910 , the PDCP layer  912 . 
     The General packet Radio Service (GPRS) Tunneling Protocol for the user plane (GTP-U) layer (GTP-U layer  1004 ) may be used for carrying user data within the GPRS core network and between the radio access network and the core network. The user data transported can be packets in any of IPv4, IPv6, or PPP formats, for example. The UDP and IP security (UDP/IP) layer (UDP/IP layer  1002 ) may provide checksums for data integrity, port numbers for addressing different functions at the source and destination, and encryption and authentication on the selected data flows. The RAN  908  and the S-GW  1006  may utilize an S1-U interface to exchange user plane data via a protocol stack comprising the L1 layer  918 , the L2 layer  920 , the UDP/IP layer  1002 , and the GTP-U layer  1004 . The S-GW  1006  and the P-GW  1008  may utilize an S5/S8a interface to exchange user plane data via a protocol stack comprising the L1 layer  918 , the L2 layer  920 , the UDP/IP layer  1002 , and the GTP-U layer  1004 . As discussed above with respect to  FIG.  9   , NAS protocols support the mobility of the UE  902  and the session management procedures to establish and maintain IP connectivity between the UE  902  and the P-GW  1008 . 
       FIG.  11    illustrates components  1100  of a core network in accordance with some embodiments. The components of the CN  1106  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  1106  may be referred to as a network slice  1102  (e.g., the network slice  1102  is shown to include the HSS  1108 , the MME(s)  928 , and the S-GW  1006 ). A logical instantiation of a portion of the CN  1106  may be referred to as a network sub-slice  1104  (e.g., the network sub-slice  1104  is shown to include the P-GW  1008  and the PCRF  1110 ). 
     NFV architectures and infrastructures may be used to virtualize one or more network functions, 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.  12    is a block diagram illustrating components, according to some example embodiments, of a system  1200  to support NFV. The system  1200  is illustrated as including a virtualized infrastructure manager (shown as VIM  1202 ), a network function virtualization infrastructure (shown as NFVI  1204 ), a VNF manager (shown as VNFM  1206 ), virtualized network functions (shown as VNF  1208 ), an element manager (shown as EM  1210 ), an NFV Orchestrator (shown as NFVO  1212 ), and a network manager (shown as NM  1214 ). 
     The VIM  1202  manages the resources of the NFVI  1204 . The NFVI  1204  can include physical or virtual resources and applications (including hypervisors) used to execute the system  1200 . The VIM  1202  may manage the life cycle of virtual resources with the NFVI  1204  (e.g., creation, maintenance, and tear down of virtual machines (VMs) associated with one or more physical resources), track VM instances, track performance, fault and security of VM instances and associated physical resources, and expose VM instances and associated physical resources to other management systems. 
     The VNFM  1206  may manage the VNF  1208 . The VNF  1208  may be used to execute EPC components/functions. The VNFM  1206  may manage the life cycle of the VNF  1208  and track performance, fault and security of the virtual aspects of VNF  1208 . The EM  1210  may track the performance, fault and security of the functional aspects of VNF  1208 . The tracking data from the VNFM  1206  and the EM  1210  may comprise, for example, performance measurement (PM) data used by the VIM  1202  or the NFVI  1204 . Both the VNFM  1206  and the EM  1210  can scale up/down the quantity of VNFs of the system  1200 . 
     The NFVO  1212  may coordinate, authorize, release and engage resources of the NFVI  1204  in order to provide the requested service (e.g., to execute an EPC function, component, or slice). The NM  1214  may provide a package of end-user functions with the responsibility for the management of a network, which may include network elements with VNFs, non-virtualized network functions, or both (management of the VNFs may occur via the EM  1210 ). 
       FIG.  13    is a block diagram illustrating components  1300 , 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.  13    shows a diagrammatic representation of hardware resources  1302  including one or more processors  1312  (or processor cores), one or more memory/storage devices  1318 , and one or more communication resources  1320 , each of which may be communicatively coupled via a bus  1322 . For embodiments where node virtualization (e.g., NFV) is utilized, a hypervisor  1304  may be executed to provide an execution environment for one or more network slices/sub-slices to utilize the hardware resources  1302 . 
     The processors  1312  (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  1314  and a processor  1316 . 
     The memory/storage devices  1318  may include main memory, disk storage, or any suitable combination thereof. The memory/storage devices  1318  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  1320  may include interconnection or network interface components or other suitable devices to communicate with one or more peripheral devices  1306  or one or more databases  1308  via a network  1310 . For example, the communication resources  1320  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  1324  may comprise software, a program, an application, an applet, an app, or other executable code for causing at least any of the processors  1312  to perform any one or more of the methodologies discussed herein. The instructions  1324  may reside, completely or partially, within at least one of the processors  1312  (e.g., within the processor&#39;s cache memory), the memory/storage devices  1318 , or any suitable combination thereof. Furthermore, any portion of the instructions  1324  may be transferred to the hardware resources  1302  from any combination of the peripheral devices  1306  or the databases  1308 . Accordingly, the memory of the processors  1312 , the memory/storage devices  1318 , the peripheral devices  1306 , and the databases  1308  are examples of computer-readable and machine-readable media. 
     For one or more embodiments, at least one of the components set forth in one or more of the preceding figures may be configured to perform one or more operations, techniques, processes, and/or methods as set forth in the Example Section below. For example, the baseband circuitry as described above in connection with one or more of the preceding figures may be configured to operate in accordance with one or more of the examples set forth below. For another example, circuitry associated with a UE, base station, network element, etc. as described above in connection with one or more of the preceding figures may be configured to operate in accordance with one or more of the examples set forth below in the example section. 
     EXAMPLE SECTION 
     The following examples pertain to further embodiments. 
     Example 1 is an apparatus for a user equipment (UE) configured to perform a handover from a source cell to a target cell in a wireless network. The apparatus includes a memory interface and a processor. The memory interface is to send or receive, to or from a memory device, packets received from the source cell and the target cell. The processor is to: perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; perform PDCP reordering of the deciphered packets in the common buffer to generate a stream of reordered packets; perform robust header compression (ROHC) decompression on the stream of reordered packets; and determine, based on a packet indication, to reset the ROHC decompression. 
     Example 2 includes the apparatus of Example 1, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during the handover from the source cell to the target cell. 
     Example 3 includes the apparatus of Example 2, wherein the PDCP header corresponds to a PDCP data protocol data unit (PDU) carry data from a data radio bearer (DRB). 
     Example 4 includes the apparatus of Example 3, wherein the PDCP data PDU corresponds to one of the packets received from the target cell. 
     Example 5 includes the apparatus of Example 1, wherein the packet indication comprises a PDCP control protocol data unit (PDU) configured to indicate a start of ROHC reset. 
     Example 6 includes the apparatus of Example 5, wherein the processor is further configured to perform physical (PHY) layer, media access control (MAC) layer, and radio link control (RLC) layer processes simultaneously on both a first set of packets received from the source cell and a second set of packets received from the target cell. 
     Example 7 includes the apparatus of Example 6, wherein the processor is further configured to perform an integrity protection check for control plane packets received from at least one of the source cell and the target cell. 
     Example 8 is a non-transitory computer-readable storage medium. The computer-readable storage medium includes instructions that when executed by a processor of a user equipment, cause the processor to: process packets received from a source cell and a target cell; perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; perform PDCP reordering of the deciphered packets in the common buffer to generate a stream of reordered packets; perform robust header compression (ROHC) decompression on the stream of reordered packets; and determine, based on a packet indication, to reset the ROHC decompression. 
     Example 9 includes the computer-readable storage medium of Example 8, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during handover from the source cell to the target cell. 
     Example 10 includes the computer-readable storage medium of Example 9, wherein the PDCP header corresponds to a PDCP data protocol data unit (PDU) carry data from a data radio bearer (DRB). 
     Example 11 includes the computer-readable storage medium of Example 10, wherein the PDCP data PDU corresponds to one of the packets received from the target cell. 
     Example 12 includes the computer-readable storage medium of Example 8, wherein the packet indication comprises a PDCP control protocol data unit (PDU) configured to indicate a start of ROHC reset. 
     Example 13 includes the computer-readable storage medium of Example 12, wherein to process the packets received from the source cell and the target cell comprises to perform physical (PHY) layer, media access control (MAC) layer, and radio link control (RLC) layer processes simultaneously on both a first set of packets received from the source cell and a second set of packets received from the target cell. 
     Example 14 includes the computer-readable storage medium of Example 13, wherein the instructions further configure the processor to perform an integrity protection check for control plane packets received from at least one of the source cell and the target cell. 
     Example 15 is a non-transitory computer-readable storage medium. The computer-readable storage medium includes instructions that when executed by a processor of a target cell in a wireless communication system, cause the processor to: receive partial packet data convergence protocol (PDCP) protocol data units (PDUs) from a source cell in the wireless communication system, the partial PDCP PDUs comprising robust header compression (ROHC) by the source cell; perform PDCP ciphering on the partial PDCP PDUs to generate ciphered PDCP PDUs; and send the ciphered PDCP PDUs to a user equipment (UE). After release of the source cell to complete a path switch to the target cell, the instructions cause the processor to: perform ROHC on data received from a core network of the wireless communication system; and generate a packet to indicate a start of a ROHC reset to the UE. 
     Example 16 includes the computer-readable storage medium of Example 15, wherein the packet to indicate the start of the ROHC reset comprises a single bit in a PDCP header set to indicate the start of the ROHC reset. 
     Example 17 includes the computer-readable storage medium of Example 15, wherein the packet to indicate the start of the ROHC reset comprises a PDCP control PDU configured to indicate the start of the ROHC reset. 
     Example 18 includes the computer-readable storage medium of Example 17, wherein the instructions further configure the processor to perform integrity protection for control plane data of the partial PDCP PDUs. 
     Example 19 is a method for a target cell for handover of a user equipment (UE) in a wireless communication system. The method includes: receiving partial packet data convergence protocol (PDCP) protocol data units (PDUs) from a source cell in the wireless communication system, the partial PDCP PDUs comprising robust header compression (ROHC) by the source cell; performing PDCP ciphering on the partial PDCP PDUs to generate ciphered PDCP PDUs; and sending the ciphered PDCP PDUs to the UE. After release of the source cell to complete a path switch to the target cell, the method further includes: performing ROHC on data received from a core network of the wireless communication system; and generating a packet to indicate a start of a ROHC reset to the UE. 
     Example 20 includes the method of Example 19, wherein the packet to indicate the start of the ROHC reset comprises a single bit in a PDCP header set to indicate the start of the ROHC reset. 
     Example 21 includes the method of Example 19, wherein the packet to indicate the start of the ROHC reset comprises a PDCP control PDU configured to indicate the start of the ROHC reset. 
     Example 22 includes the method of Example 21, further comprising performing integrity protection for control plane data of the partial PDCP PDUs. 
     Any of the above described examples may be combined with any other example (or combination of examples), unless explicitly stated otherwise. The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. 
     Embodiments and implementations of the systems and methods described herein may include various operations, which may be embodied in machine-executable instructions to be executed by a computer system. A computer system may include one or more general-purpose or special-purpose computers (or other electronic devices). The computer system may include hardware components that include specific logic for performing the operations or may include a combination of hardware, software, and/or firmware. 
     It should be recognized that the systems described herein include descriptions of specific embodiments. These embodiments can be combined into single systems, partially combined into other systems, split into multiple systems or divided or combined in other ways. In addition, it is contemplated that parameters/attributes/aspects/etc. of one embodiment can be used in another embodiment. The parameters/attributes/aspects/etc. are merely described in one or more embodiments for clarity, and it is recognized that the parameters/attributes/aspects/etc. can be combined with or substituted for parameters/attributes/etc. of another embodiment unless specifically disclaimed herein. 
     Although the foregoing has been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications may be made without departing from the principles thereof. It should be noted that there are many alternative ways of implementing both the processes and apparatuses described herein. Accordingly, the present embodiments are to be considered illustrative and not restrictive, and the description is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Metadata:
Filing Date: 20191024
Publication Date: 20231003
Grant Date: 20231003
Priority Date: 20181031
Inventors: YIU, Candy
ZHANG, YUJIAN
GUO, YI
PALAT, SUDEEP
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W36/0235", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/023", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L69/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0069", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/0072", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W12/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W28/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W12/037", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W12/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W36/08", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/0072", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W36/0235", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 70464363