Techniques for flexible reference signal patterns in wireless communications systems

A method for wireless communications at a user equipment (UE), comprising:

• transmitting, to a base station, a first message of a random access channel procedure;
• receiving, from the base station, a second message of the random access channel procedure in response to transmitting the first message, the second message comprising an indicator for triggering a tracking reference signal transmission;
• and
• receiving, from the base station, a tracking reference signal in accordance with a tracking reference signal configuration indicated by the indicator of the second message.

An apparatus for wireless communications at a user equipment (UE), comprising:

• a processor, memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• receive, from a base station, a first tracking reference signal configuration and a second tracking reference signal configuration, the first tracking reference signal configuration comprising a first set of parameters and the second tracking reference signal configuration comprising a second set of parameters;
• and
• receive, from the base station and based at least in part on an indicator for selection from among the first tracking reference signal configuration and the second tracking reference signal configuration, a tracking reference signal in accordance with the first tracking reference signal configuration or the second tracking reference signal configuration.

An apparatus for wireless communications at a user equipment (UE), comprising:

• a processor,
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the apparatus to:
• transmit, to a base station, a first message of a random access channel procedure;
• receive, from the base station, a second message of the random access channel procedure in response to transmitting the first message, the second message comprising an indicator for triggering a tracking reference signal transmission;
• and
• receive, from the base station, a tracking reference signal in accordance with a tracking reference signal configuration indicated by the indicator of the second message.