Techniques for managing transmissions of uplink data over an unlicensed radio frequency spectrum band

A method for wireless communication at a base station, comprising:

• performing a clear channel assessment (CCA) on a radio frequency spectrum band;
• transmitting, for a period following the CCA, an indication of a time division duplexing (TDD) configuration comprising an uplink period including a number of uplink subframes;
• transmitting an uplink grant indicating a first uplink subframe of the number of uplink subframes for an uplink transmission;
• and
• receiving, from a UE, a preamble indicating a start of an uplink subframe of the number of uplink subframes.

A method for wireless communication at a first base station, comprising:

• receiving, from a second base station, an indication of a time division duplexing (TDD) configuration for a period following a clear channel assessment (CCA), wherein the TDD configuration comprises an uplink period including a number of uplink subframes;
• receiving an uplink grant indicating a first uplink subframe of the number of uplink subframes for an uplink transmission;
• receiving, from a UE, a preamble indicating a start of an uplink subframe of the number of uplink subframes;
• and
• refraining from accessing a radio frequency spectrum band during a transmission of the number of uplink subframes.

An apparatus for wireless communication, comprising:

• a processor;
• and
• memory coupled to the processor, wherein the processor is configured to:
• receive an indication of a time division duplexing (TDD) configuration comprising an uplink period including a number of uplink subframes;
• receive an uplink grant indicating a first uplink subframe of the number of uplink subframes for an uplink transmission;
• perform, on a radio frequency spectrum band, a clear channel assessment (CCA) based at least in part on the uplink period;
• and
• transmit over at least one of the number of uplink subframes when the CCA is successful based at least in part on the uplink grant, wherein the uplink transmission comprises a preamble indicating a start of an uplink subframe of the number of uplink subframes.