Base station and user equipment for early-data transmission in a random access procedure
A base station transmits a paging message carrying a contention-free early-data transmission indication to a user equipment, and transmits a random access response message carrying early downlink data to the user equipment in response to a random access request message transmitted by the user equipment in a random access procedure. A base station transmits a paging message carrying a contention-based early-data transmission indication to the user equipment, and transmits an RRC response message carrying early downlink data to the user equipment in response to an RRC request message transmitted by the user equipment in a random access procedure. In a random access procedure, user equipment generates and transmits a scheduling request message to a base station after receiving early downlink data transmitted by the base station, and transmits uplink data corresponding to the early downlink data to the base station according to an uplink grant transmitted by the base station.
1. A user equipment for performing a random access procedure with a base station, comprising:
a processor, being configured to generate a scheduling request message in response to early downlink data transmitted by the base station in the random access procedure; and
a transceiver, being electrically connected with the processor and configured to:
receive a paging message including a contention-based early-data transmission indication from the base station;
transmit a random access request message to the base station on a contention-based resource related to the random access procedure;
receive a random access response message from the base station after transmitting the random access request message;
transmit a radio resource control (RRC) request message to the base station after receiving the random access response message;
receive an RRC response message carrying the early downlink data from the base station after transmitting the RRC request message;
transmit the scheduling request message to the base station after receiving the early downlink data;
receive an uplink grant from the base station after transmitting the scheduling request message to the base station; and
transmit uplink data corresponding to the early downlink data to the base station according to the uplink grant.
2. The user equipment of claim 1 , wherein the RRC request message is an RRC connection request message or an RRC early-data request message.
3. The user equipment of claim 1 , wherein the RRC request message is an RRC connection resume request message, and the RRC response message is an RRC connection resume message or an RRC connection release message.
4. The user equipment of claim 1 , wherein the processor is further configured to determine a number of retransmission of the RRC request message according to a transport block size limitation configured by the random access response message.
5. The user equipment of claim 1 , wherein the scheduling request message transmitted to the base station carries a hybrid automatic repeat request (HARQ) acknowledgement for the early downlink data.
6. A method for a user equipment to perform a random access procedure with a base station, comprising the following steps of:
receiving a paging message including a contention-based early-data transmission indication from the base station;
transmitting a random access request message to the base station on a contention-based resource related to the random access procedure;
receiving a random access response message from the base station after transmitting the random access request message;
transmitting a radio resource control (RRC) request message to the base station after receiving the random access response message;
receiving an RRC response message carrying early downlink data from the base station after transmitting the RRC request message;
generating a scheduling request message in response to the early downlink data transmitted by the base station in the random access procedure;
transmitting the scheduling request message to the base station after receiving the early downlink data;
receiving an uplink grant from the base station after transmitting the scheduling request message to the base station; and
transmitting uplink data corresponding to the early downlink data to the base station according to the uplink grant.
7. The method of claim 6 , wherein the RRC request message is an RRC connection request message or an RRC early-data request message.
8. The method of claim 6 , wherein the RRC request message is an RRC connection resume request message, and the RRC response message is an RRC connection resume message or an RRC connection release message.
9. The method of claim 6 , further comprising determining a number of retransmission of the RRC request message according to a transport block size limitation configured by the random access response message.
10. The method of claim 6 , wherein the scheduling request message transmitted to the base station carries a hybrid automatic repeat request (HARQ) acknowledgement for the early downlink data.