Qualcomm Incorporated

Abhishek Bhatnagar

Osama Lotfallah

Vitaly Drapkin

Arvind Vardarajan Santhanam

Kuo-Chun Lee

Lenaig Genevieve Chaponniere

Cogol Tina

Zhong Ren

Srinivasan Balasubramanian

Reza Shahidi

Shyamal Ramachandran

Qingxin Chen

Bhupesh Manoharlal Umatt

Carlos Marcelo Dias Pazos

Cheol Hee Park

Vikram Singh

Mona Agrawal

Cherng-Shung Hsu

Uttam Pattanayak

Qin Xue Frantti

Flora Pui San Chan

Rishav Rej

Adam Hebein

Swathi Seshadri

Manisha Priyadarshini

Brian A'hearn

Tom Chin

Haris Zisimopoulos

Shailesh Maheshwari

Min Wang

Ajith Tom Payyappilly

Jun Hu

Vamsi Dokku

Hariharan Sukumar

Krishna Chaitanya Mukkera

Dominique Francois Bressanelli

Subashini Krishnamurthy

Hemanth Kumar Rayapati

Wei-Jei Song

Bhanu Kiran Janga

Rajeev Pal

Sandeep Ramannavar

Vidula Rajeev Kurundkar

Kanuganti Rajeswar Reddy

Anisha Elizabeth Jonas

Sohrab Ahmad

Zhiyuan Lu

Quanling Zhang

Vamsi Krishna Dokku

Methods, systems, and devices for wireless communications are described. Generally, the described techniques provide for efficiently falling back from one RAT to another RAT while maximizing the services available to a UE. When a request from a UE for communicating with a base station using one RAT is rejected by a network node for unexpected causes, the UE may use the techniques described herein to fallback to an appropriate RAT. For instance, after receiving a response indicating that a request including fifth generation (5G) parameters is rejected, the UE may drop the 5G parameters and fall back to fourth generation (4G), rather than falling back to second generation (2G) or third generation (3G). The unexpected causes may be preconfigured and may be determined based on a number of factors, including a subscription of the UE, a public land mobile network (PLMN) associated with the network node, etc.

Radio access technology switching based on network support

A method is provided. The method may be performed by a UE. The method includes attempting to attach to or to perform a tracking area update in an EPS network to obtain voice services for a number of times. The method includes starting a modified timer based on a failure to attach to or to perform the tracking area update in an EPS network for the number of times and based on a configuration parameter. The modified timer may be modified based on a default timer. The method includes keeping an S1 mode enabled when starting the modified timer. The method includes attempting to obtain the voice services based on one or more access technologies other than EPS. The method includes attaching to or performing a tracking area update in the EPS network to obtain voice services based on the modified timer.

IMS voice support in network using EPS fallback and having 4G coverage holes

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may establish, using a first subscription of the UE, a first communication connection associated with a first service. The UE may establish, using a second subscription of the UE, a second communication connection associated with a second service. The UE may operate in a dual subscriber identity module (SIM) dual active (DSDA) mode based at least in part on establishing the first communication connection and establishing the second communication connection. The UE may perform an action to maintain concurrent services, including the first service and the second service, while operating in the DSDA mode. Numerous other aspects are described.

Maintaining concurrent services in a dual active mode

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may detect that a first subscription, of a plurality of subscriptions associated with the UE, is associated with an active service on a first cellular network. The UE may search, for a second subscription of the plurality of subscriptions, for radio access technologies (RATs) and frequency bands that are compatible with a dual active mode of the UE. In some aspects, the UE may detect that the active service on the first cellular network has ended. Accordingly, the UE may search, for the second subscription, for RATs and frequency bands that are compatible with the dual active mode of the UE and for RATs and frequency bands that are incompatible with the dual active mode, before expiry of a timer associated with a power saving state. Numerous other aspects are described.

Radio access technology searching in dual active mode

Aspects are provided which allow a UE to disable measurements of reference signals from 5G base stations which are inapplicable to EN-DC. The UE may receive a reference signal from a base station. The UE may identify a frequency range. The UE may determine whether to measure the reference signal based on whether the reference signal is within the identified frequency range. The UE may refrain from measuring the reference signal in response to the determination. The UE may also refrain from measuring the reference signal in response to a SIB received at the UE not including a ULI, or in response to a frequency associated with the reference signal not being in a list of supported bands for EN-DC. As a result, inter-RAT handovers from LTE base stations to 5G base stations are prevented, UE power consumption is thereby saved, and support for EN-DC is maintained.

Measurement disabling in frequency ranges

Aspects disclosed herein facilitate security handling of 5GS to EPC reselection are disclosed herein. An example method at a UE includes transmitting a first TAU request, the first TAU request encoded using a first security context associated with a first RAT, the first TAU request being integrity protected using a first uplink count based on the first security context, and the first TAU request including a first set of information including an identifier mapped to a second RAT associated with the first network entity. The example method also includes transmitting a second TAU request, the second TAU request including the first set of information, the second TAU request being integrity protected using a second uplink count. The example method also includes communicating based on a mapped security context based on the first security context and at least one of the first uplink count or the second uplink count.

Security handling of 5GS to EPC reselection

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer storage media, for wireless communication by a user equipment (UE). In one aspect, the UE is configured to generate a handover request related to a wireless communication session between the UE and a wireless local area network (WLAN) device, and establish, independent of an access check, a radio resource control (RRC) connection with a base station. In another aspect, the UE is configured to perform an access check based on a bias value, and establish an RRC connection with a base station based on a result of the access check. The access check performed based on a communication indicator related to a wireless communication session between the UE and a WLAN device.

Access check optimization for handover from wireless local area network (WLAN) and other inter radio access technology (IRAT)

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may be configured to include procedures to mitigate denial of service (DoS) attack by a rogue base station when the initial non-access stratum (NAS) messages between the UE and a mobility management entity (MME) is unprotected. UE may maintain a temporary forbidden network list, which resides outside a subscriber identity module (SIM), and update a forbidden network list, which resides on the SIM, only under certain conditions. For example, a visited network, from which the UE receives a reject message, may be added to the forbidden network list on the SIM only when a counter associated with the visited network is equal to a maximum counter value, which is configured by the UE.

Forbidden network list management

Methods, systems, and devices for wireless communication are described for inter-RAT mobility from a first radio access technology (RAT) to a second RAT, including cases in which different RATs correspond to different generations of networks. Approaches described herein include providing a preemptive indication of inter-RAT mobility for one or more geographic areas such to a user equipment (UE). The UE can thus use a mobility procedure to transition from the first RAT to the second RAT that is supported in the UE's location without first attempting an unsupported mobility procedure, reducing transition latency.

Preemptive indication of inter-rat mobility

Methods and apparatus are provided for avoiding attempts by a UE to attach to a RAT network when that RAT network is unavailable. According to certain aspects, the UE may detect scenarios when the RAT network is unavailable and take preemptive action to prevent the UE from attempting to acquire service on that RAT. For example, the UE may effectively remove that RAT from a list of supported RATs by sending a UE capability message indicating that RAT is not supported, which may prevent network-initiated transitions of the UE to that RAT. The UE may also remove the unavailable RAT from an internal list of supported RATs, which may prevent UE-initiated transitions to that RAT.

Methods and systems for avoiding transitions between radio access technologies when packet data networks are inaccessible

Methods, computer-readable medium, and apparatus are described for coordinating system selection among a set of nodes. The described aspects include determining that a node is part of a subset of nodes, wherein each node in the subset of nodes performs one or more system scans for a set of nodes that includes the subset of nodes, performing the one or more system scans by the node on one or more Radio Access Technologies (RATs) in response to determining that the node is part of the subset of nodes, obtaining one or more system scan results from the one or more system scans on the one or more RATs, and transmitting the one or more system scan results to the set of nodes.

Methods and apparatus for coordinating system selection among a set of nodes

Methods, systems, apparatuses and devices are described for managing a call during radio link failure. In one embodiment, radio link failure over a radio access technology may be detected during or after a call setup procedure. A public land mobile network and an equivalent public land mobile network may be selected. An initial search for cells of the radio access technology may be performed over the selected public land mobile network and the equivalent public land mobile network. The initial search may be performed once or twice based on a configurable parameter.

Enhance performance of making an emergency call during radio link failure over radio access technology

Growing community of inventors

San Diego, CA, United States of America

Abhishek Bhatnagar