ENHANCED SESSION AND MOBILITY MANAGEMENT INTERACTION FOR MOBILE INITIATED CONNECTION ONLY MODE USER

EQUIPMENTS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present Application for Patent claims benefit of U.S. Provisional Patent Application Serial No. 62/473,795, filed March 20, 2017, and U.S. Patent Application No. 15/922,991, filed March 16, 2018, both of which are hereby expressly incorporated by reference in their entirety.

Field

[0002] The present disclosure relates generally to communication systems, and more particularly, to methods and apparatus for enhancing session and mobility management interaction for a UE in a limited reachability mode, such as a Mobile Initiated Connection Only (MICO) mode.

Background

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include Long Term Evolution (LTE) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0004] In some examples, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). In LTE or LTE-A network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation or 5G network), a wireless multiple access communication system may include a number of distributed units (DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs), transmission reception points (TRPs), etc.) in communication with a number of central units (CUs) (e.g., central nodes (CNs), access node controllers (ANCs), etc.), where a set of one or more distributed units, in communication with a central unit, may define an access node (e.g., a new radio base station ( R BS), a new radio node-B ( R NB), a network node, 5G NB, eNB, etc.). A base station or DU may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or distributed unit).

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of an emerging telecommunication standard is new radio (NR), for example, 5G radio access. NR is a set of enhancements to the LTE mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL) as well as support beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0006] However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

[0007] The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled "Detailed Description" one will understand how the features of this disclosure provide advantages that include improved communications between access points and stations in a wireless network. [0008] Certain aspects of the present disclosure generally relate to methods and apparatus for enhancing session and mobility management interaction for a UE in a Mobile Initiated Connection Only (MICO) mode.

[0009] Certain aspects provide a method for communication by a network entity. The method generally includes determining a mobility reachability mode of a user equipment (UE) and taking action, based on the determination, to prevent a data source in the network from reaching the UE.

[0010] Certain aspects provide an apparatus for communication by a network entity. The apparatus generally includes means for determining a mobility reachability mode of a user equipment (UE) and means for taking action, based on the determination, to prevent a data source in the network from reaching the UE.

[0011] Certain aspects provide a computer readable medium having instructions stored thereon. The instructions generally include instructions for determining a mobility reachability mode of a user equipment (UE) and instructions for taking action, based on the determination, to prevent a data source in the network from reaching the UE.

[0012] Certain aspects provide an apparatus for communication by a network entity. The apparatus generally includes at least one processor configured to determine a mobility reachability mode of a user equipment (UE) and take action, based on the determination, to prevent a data source in the network from reaching the UE, and a memory coupled with the at least one processor.

[0013] Aspects generally include methods, apparatus, systems, computer readable mediums, and processing systems, as substantially described herein with reference to and as illustrated by the accompanying drawings.

[0014] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

[0016] FIG. 1 is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure.

[0017] FIGS. 2A-2D are block diagrams illustrating examples of logical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure.

[0018] FIG. 3 is a diagram illustrating an example physical architecture of a distributed RAN, in accordance with certain aspects of the present disclosure.

[0019] FIG. 4 is a block diagram conceptually illustrating a design of an example BS and user equipment (UE), in accordance with certain aspects of the present disclosure.

[0020] FIG. 5 is a diagram showing examples for implementing a communication protocol stack, in accordance with certain aspects of the present disclosure.

[0021] FIG. 6 illustrates an example of a DL-centric subframe, in accordance with certain aspects of the present disclosure.

[0022] FIG. 7 illustrates an example of an UL-centric subframe, in accordance with certain aspects of the present disclosure.

[0023] FIG. 8 illustrates an example call flow diagram for UE registration.

[0024] FIG. 9 illustrates an example call flow diagram for PDU session establishment.

[0025] FIG. 10 illustrates an example call flow diagram for a UE-triggered service request in a connected idle mode. [0026] FIG. 11 illustrates an example call flow diagram for a UE-triggered service request in a connected mode.

[0027] FIG. 12 illustrates an example call flow diagram for a network service request.

[0028] FIG. 13 illustrates example operations 1300 for communications by a network entity, in accordance with aspects of the present disclosure.

[0029] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation.

DETAILED DESCRIPTION

[0030] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for enhance session and mobility management interaction for a UE in a Mobile Initiated Connection Only (MICO) mode in wireless communications systems operating according to new radio (NR) (new radio access technology or 5G technology) technologies.

[0031] NR may support various wireless communication services, such as Enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond), millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz), massive MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low latency communications (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTI) to meet respective quality of service (QoS) requirements. In addition, these services may co-exist in the same subframe.

[0032] The following description provides examples, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0033] The techniques described herein may be used for various wireless communication networks such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as R (e.g. 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash- OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). NR is an emerging wireless communications technology under development in conjunction with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and LTE- Advanced (LTE-A) are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G and/or 4G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems, such as 5G and later, including NR technologies. EXAMPLE WIRELESS COMMUNICATIONS SYSTEM

[0034] FIG. 1 illustrates an example wireless network 100, such as a new radio (NR) or 5G network, in which aspects of the present disclosure may be performed to enhance session and mobility management interaction for a UE 120m in a Mobile Initiated Connection Only (MICO) mode. For example, one or more network entities may be configured to perform operations 1300 described below with reference to FIG. 13 to prevent attempts to access UE 120m while it is in the MICO mode.

[0035] As illustrated in FIG. 1, the wireless network 100 may include a number of BSs 110 and other network entities. A BS may be a station that communicates with UEs. Each BS 110 may provide communication coverage for a particular geographic area. In 3 GPP, the term "cell" can refer to a coverage area of a Node B and/or a Node B subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term "cell" and eNB, Node B, 5G NB, AP, NR BS, NR BS, or TRP may be interchangeable. In some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station. In some examples, the base stations may be interconnected to one another and/or to one or more other base stations or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as a direct physical connection, a virtual network, or the like using any suitable transport network.

[0036] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a frequency channel, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

[0037] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1, the BSs 110a, 110b and 110c may be macro BSs for the macro cells 102a, 102b and 102c, respectively. The BS HOx may be a pico BS for a pico cell 102x. The BSs HOy and HOz may be femto BS for the femto cells 102y and 102z, respectively. A BS may support one or multiple (e.g., three) cells.

[0038] The wireless network 100 may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., a BS or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions for other UEs. In the example shown in FIG. 1, a relay station 11 Or may communicate with the BS 110a and a UE 120r in order to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, etc.

[0039] The wireless network 100 may be a heterogeneous network that includes BSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless network 100. For example, macro BS may have a high transmit power level (e.g., 20 Watts) whereas pico BS, femto BS, and relays may have a lower transmit power level (e.g., 1 Watt).

[0040] The wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0041] A network controller 130 may be coupled to a set of BSs and provide coordination and control for these BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with one another, e.g., directly or indirectly via wireless or wireline backhaul. [0042] The UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered evolved or machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices.

[0043] In FIG. 1, a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on the downlink and/or uplink. A dashed line with double arrows indicates interfering transmissions between a UE and a BS.

[0044] Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a 'resource block') may be 12 subcarriers (or 180 kHz). Consequently, the nominal FFT size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8 or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

[0045] While aspects of the examples described herein may be associated with LTE technologies, aspects of the present disclosure may be applicable with other wireless communications systems, such as NR. NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using time division duplex (TDD). A single component carrier bandwidth of 100 MHz may be supported. NR resource blocks may span 12 sub-carriers with a sub-carrier bandwidth of 75 kHz over a 0.1 ms duration. Each radio frame may consist of 50 subframes with a length of 10 ms. Consequently, each subframe may have a length of 0.2 ms. Each subframe may indicate a link direction (i.e., DL or UL) for data transmission and the link direction for each subframe may be dynamically switched. Each subframe may include DL/UL data as well as DL/UL control data. UL and DL subframes for NR may be as described in more detail below with respect to FIGs. 6 and 7. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. MFMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. Multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. Alternatively, NR may support a different air interface, other than an OFDM-based. NR networks may include entities such CUs and/or DUs.

[0046] In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs). In this example, the UE is functioning as a scheduling entity, and other UEs utilize resources scheduled by the UE for wireless communication. A UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may optionally communicate directly with one another in addition to communicating with the scheduling entity.

[0047] Thus, in a wireless communication network with a scheduled access to time- frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more subordinate entities may communicate utilizing the scheduled resources.

[0048] As noted above, a RAN may include a CU and DUs. A NR BS (e.g., eNB, 5G Node B, Node B, transmission reception point (TRP), access point (AP)) may correspond to one or multiple BSs. NR cells can be configured as access cell (ACells) or data only cells (DCells). For example, the RAN (e.g., a central unit or distributed unit) can configure the cells. DCells may be cells used for carrier aggregation or dual connectivity, but not used for initial access, cell selection/reselection, or handover. In some cases DCells may not transmit synchronization signals— in some case cases DCells may transmit SS. NR BSs may transmit downlink signals to UEs indicating the cell type. Based on the cell type indication, the UE may communicate with the NR BS. For example, the UE may determine NR BSs to consider for cell selection, access, handover (HO), and/or measurement based on the indicated cell type.

[0049] FIG. 2A illustrates an example logical architecture 200 of a New Radio (NR) access network, which may be implemented in the wireless communication system illustrated in FIG. 1. A UE 202 may access a radio access network (RAN) 204 via an NR air interface 206. The RAN may communicate with a user plane function (UPF) 208 via an N3 interface 210. Communications between different UPFs 208 may be conveyed via an N9 interface 212. The UPFs may communicate with a data network (DN) (e.g., the Internet, network-operator-provided services) 214 via one or more N6 interfaces 216. The UE may communicate with one or more core access and mobility management functions (AMFs) 218 via an Nl interface 220. The RAN may communicate with the one or more AMFs via an N2 interface 222. The UPFs may communicate with a session management function (SMF) 226 via an N4 interface 228.

[0050] Communications between different AMFs 218 may be conveyed via an N14 interface 230. The AMFs may communicate with the SMF 226 via an Ni l interface 232. The AMFs may communicate with a policy control function (PCF) 234 via an N15 interface 236. The SMF may communicate with the PCF via an N7 interface 238. The PCF may communicate with an application function (AF) 240 via an N5 interface 242. The AMFs may communicate with an authentication server function (AUSF) 244 via an N12 interface 246. The AMFs may communicate with a unified data management (UDM) 248 via an N8 interface 250. The SMF may communicate with the UDM via an N10 interface 252. The AUSF may communicate with the UDM via an N13 interface 254.

[0051] While the example architecture 200 illustrates a single UE, the present disclosure is not so limited, and the architecture may accommodate any number of UEs. Similarly, the architecture shows the UE accessing a single DN, but the present disclosure is not so limited, and the architecture accommodates a UE communicating with a plurality of DNs, as described below with reference to FIG. 2B.

[0052] FIG. 2B illustrates an example logical architecture 260 of a New Radio (NR) access network (RAN), which may be implemented in the wireless communication system illustrated in FIG. 1. The logical architecture 250 is similar to the logical architecture 200 shown in FIG. 2A, with many of the same entities shown and labeled with the same labels. Thus, only differences from FIG. 2A will be described. The UE 202 in FIG. 2B is accessing two DNs, 214a and 214b, via the RAN 204. The RAN communicates with a first UPF 208a via a first N3 interface 210a. The RAN also communicates with a second UPF 208b via a second N3 interface 210b. Each UPF communicates with a corresponding DN 214a or 214b via a corresponding N6 interface 216a or 216b. Similarly, each UPF communicates with a corresponding SMF 226a or 226b via a corresponding N4 interface 228a or 228b. Each SMF communicates with the AMF 218 via a corresponding Ni l interface 232a or 232b. Similarly, each SMF communicates with the PCF via a corresponding N7 interface 238a or 238b. [0053] FIG. 2C illustrates an example logical architecture 270 of a New Radio (NR) access network (RAN), which may be implemented in the wireless communication system illustrated in FIG. 1. The logical architecture 270 is similar to the logical architecture 200 shown in FIG. 2A, with many of the same entities shown and labeled with the same labels. Thus, only differences from FIG. 2A will be described. In the logical architecture 270, the UE is roaming, and is therefore connected with the home physical land mobile network (HPLMN) of the UE via certain entities in the visited physical land mobile network (VPLMN). In particular, the SMF communicates with the VPLMN PCF (vPCF) 234v, but some policy information regarding the UE's access to the DN may be retrieved from the HPLMN PCF (hPCF) 234h via a roaming N7r interface 238r. In FIG. 2C, the UE is able to access the DN via the VPLMN.

[0054] FIG. 2D illustrates an example logical architecture 280 of a New Radio (NR) access network (RAN), which may be implemented in the wireless communication system illustrated in FIG. 1. The logical architecture 280 is similar to the logical architecture 270 shown in FIG. 2C, with many of the same entities shown and labeled with the same labels. Thus, only differences from FIG. 2C will be described. In the logical architecture 280, the UE is roaming, and is therefore connected with the home physical land mobile network (HPLMN) of the UE via certain entities in the visited physical land mobile network (VPLMN). Unlike FIG. 2C, the UE in FIG. 2D is accessing a DN that the UE is not able to access via the VPLMN. Differences from FIG. 2C include that the UPF in the VPLMN communicates with the VPLMN SMF (V-SMF) 226v via an N4 interface 228v, while the UPF in the HPLMN communicates with the HPLMN SMF (H-SMF) 226h via an N4 interface 228h. The UPF of the VPLMN communicates with the UPF of the HPLMN via an N9 interface 282. Similarly, the V-SMF communicates with the H-SMF via an N16 interface 284.

[0055] Operations performed and protocols used by the various entities shown in the exemplary logical architectures 200, 250, 270, and 280 in FIGs. 2A-2D are described in more detail in documents "TS 23.501; System Architecture for the 5G System; Stage 2 (Release 15)" and "TS 23.502; Procedures for the 5G System; Stage 2 (Release 15)," both which are publicly available.

[0056] FIG. 3 illustrates an example physical architecture of a distributed RAN 300, according to aspects of the present disclosure. A centralized core network unit (C-CU) 302 may host core network functions. The C-CU may be centrally deployed. C-CU functionality may be offloaded (e.g., to advanced wireless services (AWS)), in an effort to handle peak capacity.

[0057] A centralized RAN unit (C-RU) 304 may host one or more access network controller (ANC) functions. Optionally, the C-RU may host core network functions locally. The C-RU may have distributed deployment. The C-RU may be closer to the network edge.

[0058] A data unit (DU) 306 may host one or more TRPs (edge node (EN), an edge unit (EU), a radio head (RH), a smart radio head (SRH), or the like). The DU may be located at edges of the network with radio frequency (RF) functionality.

[0059] As will be described in more detail with reference to FIG. 5, the Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU or CU (e.g., TRP or ANC, respectively). According to certain aspects, a BS may include a central unit (CU) (e.g., C-CU 302) and/or one or more distributed units (e.g., one or more transmission and reception points (TRPs)).

[0060] FIG. 4 illustrates example components of the BS 110 and UE 120 illustrated in FIG. 1, which may be used to implement aspects of the present disclosure. As described above, the BS may include a TRP. One or more components of the BS 110 and UE 120 may be used to practice aspects of the present disclosure. For example, antennas 452, Tx/Rx 222, processors 466, 458, 464, and/or controller/processor 480 of the UE 120 and/or antennas 434, processors 460, 420, 438, and/or controller/processor 440 of the BS 110 may be used to perform the operations described herein and illustrated with reference to FIG. 13.

[0061] At the base station 110, a transmit processor 420 may receive data from a data source 412 and control information from a controller/processor 440. The control information may be for the Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), etc. The data may be for the Physical Downlink Shared Channel (PDSCH), etc. The processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs) 432a through 432t. For example, the TX MIMO processor 430 may perform certain aspects described herein for RS multiplexing. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 432 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators 432a through 432t may be transmitted via antennas 434a through 434t, respectively.

[0062] At the UE 120, antennas 452a through 452r may receive the downlink signals from the base station 110 and may provide received signals to the demodulators (DEMODs) 454a through 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator 454 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all the demodulators 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. For example, MIMO detector 456 may provide detected RS transmitted using techniques described herein. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to a data sink 460, and provide decoded control information to a controller/processor 480.

[0063] On the uplink, at the UE 120, a transmit processor 464 may receive and process data (e.g., for the Physical Uplink Shared Channel (PUSCH)) from a data source 462 and control information (e.g., for the Physical Uplink Control Channel (PUCCH) from the controller/processor 480. The transmit processor 464 may also generate reference symbols for a reference signal. The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 if applicable, further processed by the demodulators 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the base station 110. At the BS 110, the uplink signals from the UE 120 may be received by the antennas 434, processed by the modulators 432, detected by a MIMO detector 436 if applicable, and further processed by a receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller/processor 440.

[0064] The controllers/processors 440 and 480 may direct the operation at the base station 110 and the UE 120, respectively. The processor 440 and/or other processors and modules at the base station 110 may perform or direct, e.g., the execution of the functional blocks illustrated in FIGs. 9-10, and/or other processes for the techniques described herein. The processor 480 and/or other processors and modules at the UE 120 may also perform or direct processes for the techniques described herein. The memories 442 and 482 may store data and program codes for the BS 110 and the UE 120, respectively. A scheduler 444 may schedule UEs for data transmission on the downlink and/or uplink.

[0065] FIG. 5 illustrates a diagram 500 showing examples for implementing a communications protocol stack, according to aspects of the present disclosure. The illustrated communications protocol stacks may be implemented by devices operating in a in a 5G system (e.g., a system that supports uplink-based mobility). Diagram 500 illustrates a communications protocol stack including a Radio Resource Control (RRC) layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a Radio Link Control (RLC) layer 520, a Medium Access Control (MAC) layer 525, and a Physical (PHY) layer 530. In various examples the layers of a protocol stack may be implemented as separate modules of software, portions of a processor or ASIC, portions of non- collocated devices connected by a communications link, or various combinations thereof. Collocated and non-collocated implementations may be used, for example, in a protocol stack for a network access device (e.g., ANs, CUs, and/or DUs) or a UE.

[0066] A first option 505-a shows a split implementation of a protocol stack, in which implementation of the protocol stack is split between a centralized network access device (e.g., an ANC 202 in FIG. 2) and distributed network access device (e.g., DU 208 in FIG. 2). In the first option 505-a, an RRC layer 510 and a PDCP layer 515 may be implemented by the central unit, and an RLC layer 520, a MAC layer 525, and a PHY layer 530 may be implemented by the DU. In various examples the CU and the DU may be collocated or non-collocated. The first option 505-a may be useful in a macro cell, micro cell, or pico cell deployment.

[0067] A second option 505-b shows a unified implementation of a protocol stack, in which the protocol stack is implemented in a single network access device (e.g., access node (AN), new radio base station (NR BS), a new radio Node-B (NR NB), a network node (NN), or the like.). In the second option, the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530 may each be implemented by the AN. The second option 505-b may be useful in a femto cell deployment.

[0068] Regardless of whether a network access device implements part or all of a protocol stack, a UE may implement an entire protocol stack (e.g., the RRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525, and the PHY layer 530).

[0069] FIG. 6 is a diagram 600 showing an example of a DL-centric subframe. The DL-centric subframe may include a control portion 602. The control portion 602 may exist in the initial or beginning portion of the DL-centric subframe. The control portion 602 may include various scheduling information and/or control information corresponding to various portions of the DL-centric subframe. In some configurations, the control portion 602 may be a physical DL control channel (PDCCH), as indicated in FIG. 6. The DL-centric subframe may also include a DL data portion 604. The DL data portion 604 may sometimes be referred to as the payload of the DL-centric subframe. The DL data portion 604 may include the communication resources utilized to communicate DL data from the scheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE). In some configurations, the DL data portion 604 may be a physical DL shared channel (PDSCH).

[0070] The DL-centric subframe may also include a common UL portion 606. The common UL portion 606 may sometimes be referred to as an UL burst, a common UL burst, and/or various other suitable terms. The common UL portion 606 may include feedback information corresponding to various other portions of the DL-centric subframe. For example, the common UL portion 606 may include feedback information corresponding to the control portion 602. Non-limiting examples of feedback information may include an ACK signal, a NACK signal, a HARQ indicator, and/or various other suitable types of information. The common UL portion 606 may include additional or alternative information, such as information pertaining to random access channel (RACH) procedures, scheduling requests (SRs), and various other suitable types of information. As illustrated in FIG. 6, the end of the DL data portion 604 may be separated in time from the beginning of the common UL portion 606. This time separation may sometimes be referred to as a gap, a guard period, a guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the subordinate entity (e.g., UE)) to UL communication (e.g., transmission by the subordinate entity (e.g., UE)). One of ordinary skill in the art will understand that the foregoing is merely one example of a DL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

[0071] FIG. 7 is a diagram 700 showing an example of an UL-centric subframe. The UL-centric subframe may include a control portion 702. The control portion 702 may exist in the initial or beginning portion of the UL-centric subframe. The control portion 702 in FIG. 7 may be similar to the control portion described above with reference to FIG. 6. The UL-centric subframe may also include an UL data portion 704. The UL data portion 704 may sometimes be referred to as the payload of the UL-centric subframe. The UL portion may refer to the communication resources utilized to communicate UL data from the subordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS). In some configurations, the control portion 702 may be a physical DL control channel (PDCCH).

[0072] As illustrated in FIG. 7, the end of the control portion 702 may be separated in time from the beginning of the UL data portion 704. This time separation may sometimes be referred to as a gap, guard period, guard interval, and/or various other suitable terms. This separation provides time for the switch-over from DL communication (e.g., reception operation by the scheduling entity) to UL communication (e.g., transmission by the scheduling entity). The UL-centric subframe may also include a common UL portion 706. The common UL portion 706 in FIG. 7 may be similar to the common UL portion 706 described above with reference to FIG. 7. The common UL portion 706 may additional or alternative include information pertaining to channel quality indicator (CQI), sounding reference signals (SRSs), and various other suitable types of information. One of ordinary skill in the art will understand that the foregoing is merely one example of an UL-centric subframe and alternative structures having similar features may exist without necessarily deviating from the aspects described herein.

[0073] In some circumstances, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying that communication through the scheduling entity (e.g., UE or BS), even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0074] A UE may operate in various radio resource configurations, including a configuration associated with transmitting pilots using a dedicated set of resources (e.g., a radio resource control (RRC) dedicated state, etc.) or a configuration associated with transmitting pilots using a common set of resources (e.g., an RRC common state, etc.). When operating in the RRC dedicated state, the UE may select a dedicated set of resources for transmitting a pilot signal to a network. When operating in the RRC common state, the UE may select a common set of resources for transmitting a pilot signal to the network. In either case, a pilot signal transmitted by the UE may be received by one or more network access devices, such as an AN, or a DU, or portions thereof. Each receiving network access device may be configured to receive and measure pilot signals transmitted on the common set of resources, and also receive and measure pilot signals transmitted on dedicated sets of resources allocated to the UEs for which the network access device is a member of a monitoring set of network access devices for the UE. One or more of the receiving network access devices, or a CU to which receiving network access device(s) transmit the measurements of the pilot signals, may use the measurements to identify serving cells for the UEs, or to initiate a change of serving cell for one or more of the UEs.

EXAMPLE CALL FLOWS FOR A UE IN A REACHABILITY MODE

[0075] Some wireless systems (e.g., 5G systems, eMBB systems) support a device (e.g., a UE) operating in a mobility management mode or UE reachability mode where the device establishes a connection only when it wants to initiate a data transfer. To facilitate the following description, the generic phrase "reachability mode" may be used to refer to either a mobility management mode or a UE reachability mode. One example of a reachability mode is referred to as a mobility initiated connection only (MICO) mode.

[0076] Aspects of the present disclosure provide techniques that may help prevent or limit network entities from trying to reach a device operating in such a reachability mode. Preventing network entities from trying to reach a device in a reachability mode may help reduce overhead incurred when attempting to reach a device that is unreachable.

[0077] A UE may indicate a preference (e.g., via a request) to operate in a MICO mode during initial registration or registration update. FIG. 8 illustrates an example call flow diagram 800 for UE registration, during which a UE may indicate such a preference. In some cases, during registration, the UE may include a "UE reachability mode" indication if the UE is operating in or desires to operate in a MICO mode.

[0078] Various functional network entities are shown in FIG. 8, such as a Core Access and Mobility Management Function (AMF), a User plane function (UPF), Session management function (SMF), a Policy Control Function (PCF), and an Authentication Service Function (AUSF) network entities.

[0079] The AMF network entity, based on local configuration, UE indicated preferences, UE subscription information and network policies (or any combination thereof), may determine whether the MICO mode is allowed for the UE and may indicate this to the UE during Registration procedure. The UE and core network may re-initiate (or exit) the MICO mode at subsequent registration signaling. If MICO mode is not indicated explicitly in Registration, then both the UE and the AMF may be configured to not use the MICO mode. The AMF may assign a registration area to the UE during the registration procedure.

[0080] When the AMF indicates the availability (allowability) of MICO mode to a UE, the registration area may not be constrained by paging area size. The network, based on local policy, and subscription information, may decide to provide an "all PLMN" registration area indication to the UE. In that case, re-registration to the same PLMN due to mobility may not apply. In other words, when the AMF indicates MICO mode to a UE, the AMF may consider the UE always unreachable while in CM-IDLE. In such cases, the CN rejects any request for downlink data delivery for an MICO UE in idle mode. The CN also defers downlink transport over NAS for SMS, location services, and the like. The UE in MICO mode may only be reachable for mobile terminated (MT) data or signaling when the UE is in CM-CONNECTED mode for the PDU sessions that are resumed. A UE in MICO mode may perform periodic registration at the expiration of periodic registration timer.

[0081] A UE in MICO mode may not need to listen to paging while in CM-IDLE. Further, a UE in MICO mode may stop any access stratum procedures in CM-IDLE, until the UE initiates CM-IDLE to CM-CONNECTED mode procedures due to one of various triggers. Such triggers may include a change in the UE (e.g. change in configuration) that requires an update its registration with the network, a periodic registration timer expires, mobile originated (MO) data pending, or MO signaling pending (e.g., SM procedure initiated).

[0082] If a registration area that is not the "all PLMN" registration area is allocated to a UE in MICO mode, then the UE determines if it is within the registration area or not when it has MO data or MO signaling.

[0083] FIG. 9 illustrates a call flow diagram 900 for a UE initiated PDU session establishment procedure, as shown in the call flow diagram 900 of FIG. 9.

[0084] In some cases, the network sends a device trigger message to the application(s) on the UE side. The trigger payload included in a Device Trigger Request message contains the information on which the application on the UE side is expected to trigger the PDU Session establishment request. Based on that information, the application(s) on the UE side triggers the PDU session establishment procedure. If the UE is simultaneously registered to a non-3GPP access via a N3IWF located in a PLMN different from the PLMN of the 3 GPP access, the functional entities in the following procedure are located in the PLMN of the 3 GPP access for non-roaming and LBO scenarios. In FIG. 9, non-roaming and roaming with local breakout is illustrated.

[0085] FIG. 10 illustrates an example call flow diagram 1000 for a UE-triggered service request in a connected idle mode. Such a procedure may be used, for example, by a 5G UE in the CM-IDLE state to request the establishment of a secure connection to an AMF. The CM-Idle state generally refers to an enhanced connected mobility state when no NAS signaling connection between the UE and AMF exists. In the CM-IDLE state, a UE can perform cell selection/reselection (while in a CM-Connected state, a UE may initiate a PDU session).

[0086] The UE in CM-IDLE state initiates the Service Request procedure in order to send uplink signaling messages, user data, or a response to a network paging request. After receiving the Service Request message, the AMF may perform authentication, and the AMF may perform the security procedure. After the establishment of a secure signaling connection to an AMF, the UE or network may send signaling messages, such as a PDU session establishment from the UE to the network, or the SMF, via the AMF, may start the user plane resource establishment for the PDU sessions requested by the network and/or indicated in the Service Request message.

[0087] For any Service Request, the AMF may respond with a Service Response message to synchronize a PDU session status between the UE and network. The AMF may also respond with a Service Reject message to the UE, if the Service Request cannot be accepted by network. For a Service Request due to user data, the network may take further actions if user plane resource establishment is not successful.

[0088] FIG. 11 illustrates an example call flow diagram 1100 for a UE-triggered service request in a connected mode. The UE-triggered Service Request procedure may be used, for example, by a 5G UE in a CM-CONNECTED state to request/establish user plane resources for PDU sessions. As noted above, the network may take further actions if user plane resource establishment is not successful. [0089] FIG. 12 illustrates an example call flow diagram 1200 for a network triggered service request. This procedure may be used when the network needs to signal something to a UE (e.g., Nl signaling to UE, Mobile-terminated SMS, PDU session User Plane resource establishment to deliver mobile terminating user data). If the UE is in the CM-IDLE state or CM-CONNECTED state, the network may initiate a network triggered Service Request procedure. If the UE is in CM-IDLE state, and Asynchronous Communication is not activated, the network sends a Paging Request to (R)AN/UE. The Paging Request triggers the Service Request procedure in the UE. If Asynchronous Communication is activated, the network suspends the Service Request procedure with (R)AN and UE, and continues the Service Request procedure with the (R)AN and the UE, for example, synchronizes the session context with the (R)AN and the UE, when the UE enters CM-CONNECTED state.

[0090] As will be described in greater detail below, in some cases, when the UPF receives downlink data of a PDU session and there is no (R)AN tunnel information stored in UPF for the PDU session, the UPF buffers the downlink data, depending on the indication previously received from the SMF based on the UE Reachability Mode. In some cases, on arrival of the first downlink data packet, the UPF may send a Data Notification message to the SMF, depending on the indication previously received from the SMF based on the UE Reachability Mode. In some cases, if the UE is in the CM- IDLE state, and the AMF determines that the UE is not reachable for paging (including the scenario in which the UE is in MICO mode), the AMF may send an Nl 1 message to the SMF, or other network functions from which AMF received the request message in step 3a, indicating the UE is not reachable. The AMF may include the UE Reachability mode if the UE is in MICO mode.

EXAMPLE ENHANCED SESSION AND MOBILITY MANAGEMENT INTERACTION FOR MICO MODE UEs

[0091] As noted above, aspects of the present disclosure provide techniques that may help prevent or limit network entities from wasting resources, by trying to reach a device operating in MICO mode.

[0092] The techniques presented herein may help avoid wasting system resources when the UE is in MICO mode, for example, as the UE should not be paged for DL data if the UE is CM-IDLE. Aspects of the present disclosure may help define the interaction between AMF and SMF network entities, when interacting with a UE operating in MICO mode.

[0093] FIG. 13 illustrates example operations 1300 for communications by a network entity, in accordance with aspects of the present disclosure. Operations 1300 may be performed, for example, by AMF and/or SMF network entities shown in FIGs. 8-12 referenced above.

[0094] Operations 1300 begin, at 1302, by determining a reachability mode of a user equipment (UE). For example, the mobility management mode may be a MICO mode. At 1304, the network entity (e.g., AMF/SMF) takes action, based on the determination, to prevent a data source in the network from reaching the UE.

[0095] In some cases, an AMF network entity may receive an indication, from the UE, that the UE is in (or requests to operate in) the reachability mode. In some cases, the AMF network entity may receive an indication, via the UE subscription profile, that the UE is to operate in the reachability mode.

[0096] In some cases, an AMF may take action to prevent the network data source from reaching the UE, for example, by buffering downlink data from the network data source rather than sending the downlink data to the UE. As another example, the AMF may refrain from sending a notification of incoming downlink data to the UE. In some cases, refraining from sending a notification of incoming downlink data to the UE may mean refraining from triggering a paging request to the UE.

[0097] In some cases, an AMF may immediately notify an SMF that a UE is in MICO mode (so it may take action to avoid attempts to reach the UE). As an alternative, the AMF may wait to notify the SMF, for example, until the UE is to be paged. In some cases, the AMF may notify the SMF of the UE Reachability mode to inform the SMF of the ability to reach the UE for DL data notification. In some cases (for any remaining PDU sessions), if a UEs Reachability Mode has changed, the AMF may notify each SMF of the new UE Mobility Mode.

[0098] As noted, on the SMF side, the determination of the reachability mode of the UE may be based on an indication from the AMF network entity. In some cases, the SMF may assume the UE is not in the reachability mode unless an indication is received from the AMF network entity that the UE is in the reachability mode. In other words, the SMF may continue to try and reach the UE unless it has been notified that the UE is not reachable.

[0099] In some cases, the SMF may prevent a network data source (e.g., the UPF network entity) from reaching the UE by rejecting a request, from that network data source, to reach the UE. The rejection may be based at least in part on the indication of the reachability mode. In some cases, the SMF may prevent the network data source from reaching the UE by configuring the network data source to not send a request to reach the UE.

[0100] In this manner, if a UE is in MICO mode, upon the UE performing a PDU session establishment, the AMF may indicate to the SMF that the UE is in MICO mode. As described above, the SMF may store this indication for further reference. For example, upon receiving the indication (that the UE is in MICO mode), the SMF may, upon PDU session establishment, indicate to the UPF to not buffer DL data and may indicate the UPF should stop sending DL Data Notifications.

[0101] In this case, the SMF may indicate to the UPF to resume buffering DL data and send DL Data Notifications if (or when) it receives (from the AMF) an indication that the UE is again reachable (e.g., no longer in MICO mode).

[0102] In another case, after the PDU session is established, upon receiving a DL Data Notification from the UPF, the SMF may be configured to refrain from triggering a DL Data Notification to the AMF for a MICO mode UE. Again, the SMF may indicate to the UPF to not buffer DL data, and may indicate to the UPF to stop sending DL Data Notifications. The SMF may resume normal behavior (e.g., again triggering DL Data Notifications) when the AMF indicates to the SMF that the UE is again reachable (e.g., no longer in MICO mode).

[0103] The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. [0104] As used herein, a phrase referring to "at least one of a list of items refers to any combination of those items, including single members. As an example, "at least one of: a, b, or c" is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

[0105] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, "determining" may include resolving, selecting, choosing, establishing and the like.

[0106] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for."

[0107] The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering.

[0108] For example, means for transmitting and/or means for receiving may comprise one or more of a transmit processor 420, a TX MIMO processor 430, a receive processor 438, or antenna(s) 434 of the base station 110 and/or the transmit processor 464, a TX MFMO processor 466, a receive processor 458, or antenna(s) 452 of the user equipment 120. Additionally, means for generating, means for multiplexing, and/or means for applying may comprise one or more processors, such as the controller/processor 440 of the base station 110 and/or the controller/processor 480 of the user equipment 120.

[0109] The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general- purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0110] If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal 120 (see FIG. 1), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special- purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0111] If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine- readable storage media may include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Readonly Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product. [0112] A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module.

[0113] Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0114] Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For example, the instructions may include instructions for performing the operations described herein and illustrated in FIGs. 8-10.

[0115] Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

[0116] It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.