Method and device for selecting cell in wireless communication system
Disclosed are method and device for selecting a cell in a wireless communication system. In particular, a method for selecting a cell by a terminal in a wireless communication system comprises the steps of: transmitting a random access preamble in a cell, which is selected by a terminal, to a base station; receiving a random access response from the base station; and, as a response to the random access response, transmitting an uplink message to the base station through a physical uplink shared channel (PUSCH), wherein the uplink message can comprises a radio resource management (RRM) measurement value which has been measured on the basis of a reference signal.
1. A method for performing a random access procedure by a user equipment (UE) in a wireless communication system, comprising:
receiving, from a base station (BS), system information including Radio resource management-Reference signal (RRM-RS) configuration information of a neighbor cell and a serving cell, wherein the RRM configuration information includes a Physical Cell Identity (PCI) of each cell;
performing a Radio resource management (RRM) measurement based on the RRM-RS configuration information;
transmitting, to the BS, a random access preamble, wherein the BS is on a cell selected by the UE based on the RRM measurement;
receiving, from the BS, a random access response; and
in response to the random access response, transmitting, to the BS, a reporting message on a Physical Uplink Shared Channel (PUSCH),
wherein the reporting message includes a Radio resource management (RRM) measurement value, which is measured based on a reference signal (RS) and a preconfigured threshold value,
wherein the RRM measurement value is reported with a PCI of the cell, and
wherein the RRM measurement value includes a Cell-specific Reference Signal (CRS)-based RRM measurement value and/or a RRM-RS-based RRM measurement value configured for the RRM measurement.
2. The method of claim 1 , wherein the RRM-RS configuration information includes one or more of RRM-RS antenna port number information, RRM-RS antenna port mapping information, RRM-RS transmission period and offset information, or RRM-RS transmission frequency/time resource information.
3. The method of claim 1 , wherein the RRM-RS configuration information is corresponding to a PCI of each cell.
4. The method of claim 1 , wherein the cell is selected, by the UE, based on the CRS-based RRM measurement value and/or the RRM-RS-based RRM measurement value for each cell.
5. The method of claim 4 , wherein a cell that transmits a RRM-RS of which RRM-RS-based RRM measurement value is a greatest is selected.
6. The method of claim 5 , when a CRS-based RRM measurement value for a cell that transmits a RRM-RS of which RRM-RS-based RRM measurement value is a greatest is smaller than a CRS-based RRM measurement value or other cell by more than a preconfigured threshold value, wherein a cell that transmits a RRM-RS of which RRM-RS-based RRM measurement value is a greatest is not selected.
7. The method of claim 4 , wherein a cell of which a weighted average value between the RRM-RS-based RRM measurement value and the CRS-based RRM measurement value is a greatest is selected.
8. The method of claim 4 , wherein a cell is selected based on the RRM-RS-based RRM measurement value among cells of which difference between a best CRS-based RRM measurement value and a CRS-based RRM measurement value for a measurement target cell is a preconfigured threshold value or less.
9. The method of claim 4 , wherein a cell is selected based on difference between a best CRS-based RRM measurement value and a CRS-based RRM measurement value for a measurement target cell, and difference between a best RRM-RS-based RRM measurement value and a RRM-RS-based measurement value for the measurement target cell.
10. The method of claim 1 , wherein the RRM includes a Reference signal receive power (RSRP) and/or a Reference signal received quality (RSRQ).
11. The method of claim 1 , wherein the RRM-RS is one of a Channel State Information-Reference Signal (CSI-RS), a Discovery Reference Signal (DRS), a precoded reference signal or a reference signal transmitted in an amorphous cell including a number of different cells or transmission points.
12. The method of claim 1 , further comprising
receiving, from the BS, the preconfigured threshold value with the random access response.
13. A user equipment (UE) for performing a random access procedure selecting a cell in a wireless communication system, comprising:
a radio frequency (RF) unit for transmitting and receiving a wireless signal; and
a processor for controlling the RF unit,
wherein the processor is configured to perform:
receiving system information including Radio resource management-Reference signal (RRM-RS) configuration information of a neighbor cell and a serving cell, wherein the RRM configuration information includes a Physical Cell Identity(PCI) of each cell;
performing a Radio resource management(RRM) measurement based on the RRM-RS configuration information;
transmitting a random access preamble to a base station (BS) on a cell selected by the UE based on the RRM measurement;
receiving a random access response from the BS; and
in response to the random access response, transmitting a reporting message on a Physical Uplink Shared Channel (PUSCH) to the BS,
wherein the reporting message includes a Radio resource management (RRM) measurement value, which is measured based on a reference signal (RS) and a preconfigured threshold value,
wherein the RRM measurement value is reported with a PCI of the cell, and
wherein the RRM measurement value includes a Cell-specific Reference Signal (CRS)-based RRM measurement value and/or a RRM-RS-based RRM measurement value configured for the RRM measurement.