US 12,089,098 B2
Feedback on network-assisted fallback to contention-based random access
Muhammad Naseer-Ul-Islam, Munich (DE); Ahmad Awada, Munich (DE); and Andreas Lobinger, Grafing (DE)
Assigned to Nokia Technologies Oy, Espoo (FI)
Appl. No. 17/633,238
Filed by Nokia Technologies Oy, Espoo (FI)
PCT Filed Aug. 14, 2019, PCT No. PCT/EP2019/071868
§ 371(c)(1), (2) Date Feb. 7, 2022,
PCT Pub. No. WO2021/028048, PCT Pub. Date Feb. 18, 2021.
Prior Publication US 2022/0295361 A1, Sep. 15, 2022
Int. Cl. H04W 4/00 (2018.01); H04W 36/00 (2009.01); H04W 74/00 (2009.01); H04W 74/0833 (2024.01)
CPC H04W 36/0072 (2013.01) [H04W 36/0058 (2018.08); H04W 74/004 (2013.01); H04W 74/0833 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus of a terminal connected to at least one network slice and being subject to a handover from a source access point to a target access point, the apparatus comprising:
at least one processor; and
at least one memory including computer program code that, when executed by the processor, cause the at least one processor to perform the following operations:
receiving a first handover command message including first handover assistance information indicative of a first pool of random access channel resources to be used by the terminal upon fallback to contention-based random access during a first handover processing;
selecting first random access channel resources as first attempt random access channel resources from the first pool of random access channel resources;
attempting a first random access to the target access point utilizing the first attempt random access channel resources;
storing, when attempting the first random access to the target access point utilizing the first attempt random access channel resources is unsuccessful, attempt related information to an attempt failure list;
receiving a second handover command message including second handover assistance information indicative of a second pool of random access channel resources to be used by the terminal upon fallback to contention-based random access during a second handover processing;
selecting second random access channel resources as second attempt random access channel resources from the second pool of random access channel resources;
attempting a second random access to the target access point utilizing the second attempt random access channel resources;
transmitting, when attempting the second random access to the target access point utilizing the second attempt random access channel resources is successful, the attempt failure list to the target access point;
trying, when a failure condition with respect to attempting the second random access to the target access point is met, to connect to a recovery access point; and
transmitting, when the trying to connect to the recovery access point is successful, the attempt failure list to the recovery access point.