Method and apparatus for transmitting a rach preamble on a wireless network

An apparatus comprising:

• a transceiver that
• receives an indication of a set of semi-statically configured random access channel resources via a higher layer signaling, where the higher layer is higher than a physical layer, and
• receives an indication of availability of a random access channel resource of at least one random access channel resource of the set of semi-statically configured random access channel resources via a dynamic physical-layer signaling, where the dynamic physical-layer signaling is within a number of slots including a random access channel slot,
• wherein the random access channel slot includes the at least one random access channel resource of the set of semi-statically configured random access channel resources;
• a controller coupled to the transceiver, where the controller determines an available random access channel resource in the random access channel slot based on the received indication of the set of semi-statically configured random access channel resources and based on the received indication of availability of the random access channel resource of the at least one random access channel resource of the set of semi-statically configured random access channel resources,
• wherein the transceiver transmits a random access channel preamble on the available random access channel resource in the random access channel slot.