3 GPP TSG RAN WG 1 Meeting 88

3 GPP TSG RAN WG 1 Meeting #88 b Spokane, USA, 3 rd – 7 th April 2017 Agenda item: 8. 1. 2. 2. 2 R 1 -17 xxxxx WF on Beam Failure Recovery Media. Tek, Ericsson, Samsung, [ZTE, CATT, OPPO, Intel, HW, Hi. Silicon, vivo]

• target channel to be monitored • NR considers control channel(s) quality for beam failure recovery – Data channel(s) quality can be reflected to g. NB via signaling in e. g. , CSI/beam reporting, or eventtriggered reporting – Monitor DL RS associated with a data channel if no control channel in the same carrier • E. g. , Du. Co with LF control and HF data

Proposal • UE Beam failure recovery mechanism includes the following steps – Step 1: Beam failure detection – Step 2: New candidate beam identification • It’s up to UE implementation on running step 2 before step 1 – Step 3: Beam failure recovery request transmission – Step 4: UE monitors g. NB response for beam failure recovery request – Note: to proceed with subsequent steps, proceeding steps should be satisfied, unless stated otherwise

Proposal • Step 1: Beam failure detection – UE monitors beam failure detection RS to assess if a beam failure trigger condition has been met – Beam failure detection RS at least includes periodic CSI-RS for beam management • SS-block can be considered, if SS-block is also used in beam management as well • DMRS for PDSCH can be considered, if there is no control channel in the same carrier – FFS: Trigger condition for declaring beam failure

Proposal • Step 2: New candidate beam identification – UE monitors beam identification RS to find a new candidate beam – Beam identification RS includes • Periodic CSI-RS for beam management, if it is configured by NW • Periodic CSI-RS with priority, SS-blocks as second priority

Proposal • Step 3: Beam failure recovery request transmission – Information carried by beam failure recovery request • Explicit/implicit information about identifying UE and new g. NB TX beam information • FFS: – Information indicating UE beam failure – Additional information, e. g. , new beam quality – Down-selection between the following options for beam failure recovery request transmission • PRACH • PUCCH • RACH-like – Beam failure recovery request resource/signal can be used for Scheduling Request • E. g. , request transmission received at serving BPL(s) is scheduling request

Proposal • Step 4: UE monitors g. NB response for beam failure recovery request – E. g. , UE further reaction if g. NB does not receive beam failure recovery request transmission • FFS: details