Method and apparatus for performing random access procedure for coverage enhancement user equipments in wireless communication system
A method and apparatus for performing a random access procedure in a wireless communication system is provided. In one embodiment, a user equipment (UE) determines a required amount of repetitions for uplink transmissions during a random access procedure, and performs repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions. The uplink transmissions may include transmission of preambles which are grouped. In another embodiment, a UE configures a communication windows for lost-cost machine-type communication (MTC) UE, and performs a random access procedure through the configured communication window.
1. A method for performing, by a user equipment (UE), a random access procedure in a wireless communication system, the method comprising:
receiving a mapping table between a number of repetitions required for correct reception of a downlink message and an estimated number of repetitions for uplink transmissions from a network;
determining a required amount of repetitions for uplink transmissions during a random access procedure based on the number of repetitions required for correct reception of the downlink message according to the mapping table; and
performing repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions.
2. The method of claim 1 , wherein the downlink message is one of system information or a paging message.
3. The method of claim 1 , wherein the uplink transmissions include transmission of preambles which are grouped.
4. The method of claim 3 , wherein the preambles are grouped based on the number of repetitions for correct reception of downlink message.
5. A user equipment (UE) in a wireless communication system, the UE comprising:
a radio frequency (RF) transceiver; and
a processor that is coupled to the RF transceiver and that:
controls the RF transceiver to receive a mapping table between a number of repetitions required for correct reception of a downlink message and an estimated number of repetitions for uplink transmissions from a network,
determines a required amount of repetitions for uplink transmissions during a random access procedure based on the number of repetitions required for correct reception of the downlink message according to the mapping table, and
controls the RF transceiver to perform repetitions for uplink transmissions based on the determined required amount of repetitions for uplink transmissions.
6. The UE of claim 5 , wherein the downlink message is one of system information or a paging message.
7. The UE of claim 5 , wherein the uplink transmissions include transmission of preambles which are grouped.
8. The UE of claim 7 , wherein the preambles are grouped based on the number of repetitions for correct reception of downlink message.