Apple Inc.
Synchronization signal design for unlicensed spectrum access using cellular communications

Abstract:

Apparatuses, systems, and methods for performing timing synchronization between a base station and a user equipment device within an unlicensed spectrum band. In some scenarios, beamforming tracking may also be performed. Upon determining that a transmission medium within the unlicensed spectrum band is available for transmission, a base station may transmit a plurality of synchronization signal blocks (SSBs), or a plurality of copies of one SSB, with associated remaining minimum system information (RMSI) blocks, within a single time instance within a SSB burst window. The SSBs may be transmitted at different frequency positions and according to distinct beamforming configurations. The SSBs and RMSI blocks may be configured such that a receiving user equipment device may determine the time-domain, and optionally the frequency-domain, position of the SSB and RMSI within the SSB burst window, to allow timing synchronization and optionally beamforming tracking.