Round Trip Time for Control Channel Multiplexing Using In-Band Full Duplex with Synchronous Orthogonal Sequence Assignment

Abstract

This paper proposes a Layer 1 (L1) control channel (CC) multiplexing scheme using in-band full duplex (FD) with synchronous orthogonal sequence assignment in the downlink and uplink to shorten the round trip time (RTT) due to hybrid automatic repeat request (HARQ). We describe the proposed L1 CC multiplexing scheme employing in-band FD associated with a cyclic-shifted Zadoff-Chu sequence and block spreading for synchronous orthogonal sequence assignments. We show the supported coverage area where the L1 CC multiplexing using in-band FD is available for various subcarrier spacings (SCSs). Finally, we show that the proposed L1 CC multiplexing scheme using in-band FD reduces the RTT due to HARQ compared to that for half duplex (HD) time division duplex (TDD) based CC multiplexing for various SCSs and slot assignments of data channels in HD TDD.