3 GPP TSG RAN WG 1 Meeting RAN

3 GPP TSG RAN WG 1 Meeting RAN 1 #88 b Spokane, USA, April 3 -7, 2017 Agenda item: 8. 1. 2. 1. 5 Document for: Decision WF on transmit diversity for DFTs. OFDM Mitsubishi Electric, Qualcomm, Interdigital, … R 1 -170 XXXX

Background • RAN 1#NR AH#1 • For PUCCH in long-duration, DFT-s-OFDM waveform is supported. • For PUCCH in long-duration, transmit antenna diversity is supported. • RAN 1#88 • For DFT-S-OFDM, following schemes can be candidates for UL diversity schemes for UL data: CDD, precoder cycling, antenna port switching, SFBC, and STBC. • RAN 1 should down select them in WI phase. • FFS the corresponding spec impact (if any) • For DFT-S-OFDM based transmission • PRB bundling size is the whole scheduled bandwidth if the scheduled bandwidth comprises a single cluster.

Background • Transmit diversity increases the link reliability in DFTs. OFDM for both data and control • Rank 1 transmission, link budget limited, unreliable or absent channel information • Low PAPR Alamouti schemes able to operate with any number of DFTs. OFDM symbol were proposed (SC-SFBC, SS-STBC, STBC) • R 1 -1704814, R 1 -1705078, R 1 -1704813, R 1 -1705578, R 1 -1705521, R 11705049

Background • Frequency-domain precoder-cycling is not fit for DFTs. OFDM • PRB/PRG cycling is PAPR destroying • RE-based cophase cycling (1/2 symbol LD-CDD) has limited performance gain (R 1 -1704814) • Time-domain antenna/precoder switching has high DM-RS overhead (1 DM-RS per antenna/precoder) and poor performance at medium/high speed (no time-domain interpolation) (R 1 -1704814) • At least for long PUCCH, Alamouti-based transmit diversity overperforms CDD • R 1 -1704813, R 1 -1705578

Proposal • For DFTs. OFDM in data and control channel, the following schemes are candidates for transmit diversity: • Low PAPR Alamouti-based transmit diversity, short delay CDD