US Patent 10404434 Discovery and random access for shared spectrum

Methods, systems, and devices for wireless communication are described that involve determining multiple beamformed transmission beams for transmission of an opportunistic or multi-beam discovery reference signal (DRS) over a shared radio frequency spectrum band. The base station may determine a contention exempt transmission (CET) period for the shared spectrum band and transmit the DRS using multiple transmission beams during CET period or the base station may perform a listen before talk (LBT) procedure, and transmit, based on the LBT procedure, the DRS over a shared radio frequency spectrum band. The base station may transmit an indication of the type of DRS transmission, a subframe offset, random access configurations, and/or error correcting codes to enable a user equipment to discover, connect to, and acquire timing information associated with the network.