On-demand system information request message

A method comprising:

• performing a random access channel (RACH) procedure by a user equipment (UE) in a wireless network, wherein a Msg1 with a preamble is sent by the UE and a Msg2 is subsequently received from the wireless network as a random access response, and wherein the preamble is associated with a dynamically assigned group X of on-demand system information block (SIB);
• sending a Msg3 with an embedded system information (SI) request by the UE to the network requesting a subset of the group X of on-demand SIB, wherein the Msg3 includes a UE identification (ID) of the UE;
• and
• monitoring a SI broadcast channel and receiving information of the group X of on-demand SIB through the SI broadcast channel upon determining a failure of ACK to the SI request.

An apparatus, comprising:

• a transceiver that transmits and receives radio frequency (RF) signals from one or more base stations (BS) in wireless network;
• a random access channel (RACH) procedure circuit that sends a Msg1 with a preamble and receives a Msg2 as a random access response;
• a system information (SI) transmitter that sends a Msg3 with an SI request message requesting one or more other on-demand SI, wherein a RACH message includes a UE identification (ID) of the UE, and wherein the UE ID in the SI request is determined based on a UE state, and wherein the UE state is one of a radio resource control (RRC) connected state, an inactive state, and an idle state;
• and
• an SI receiver that receives a Msg4 with an SI response embedded from the network and receives an unicasted message following the SI response by the UE from the network, wherein information of the one or more on-demand SI requested are included.