Clarification of the scope of the study on latency reduction techniques for LTE 3GPP TSG RAN Meeting #71RP-16xxxx Göteborg, Sweden, March , 2016 Document for: Discussion Agenda Item: Huawei, HiSilicon, ZTE, Nokia, Alcatel-Lucent, Alcatel- Lucent Shanghai Bell

Background (1/2) RAN1 could not determine whether frame structure 3 (FS3) is in the scope of the study on TTI reduction FS3 is introduced for LAA with only DL in Rel-13. CRs were approved in December FS3 is being enhanced with UL in an on-going WI approved in December The study on latency reduction techniques for LTE was approved in March It could not have included LAA in its scope.

Background (2/2) RAN1 could not determine whether new TDD frame structure based on frame structure 2 is in the scope of the study on TTI reduction The following was almost agreed in RAN1#84, but consensus was not reached mainly due to the concern on whether frame structure 3 is also included. –Investigate at least the feasibility of TDD latency reduction at least including following examples New subframe types with both symbol(s) for downlink transmission and symbol(s) for uplink transmission can be considered More Downlink-to-Uplink switching points in a radio frame can be considered Note that GP should be considered The case of multi-carrier with different DL/UL configurations should be considered

Proposal The following clarification is proposed: –FS1 is part of the study on latency reduction techniques for LTE –For FS2, new subframe types and more DL/UL switching points need to be studied For FS2, the study can be in the latency reduction SI or in a separate SI –FS3 is not part of the study on latency reduction techniques for LTE Shorter TTI for FS3 can be considered in a separate SI or WI after RAN1 has completed the design of LAA with DL+UL