Method and apparatus for performing initial access procedure in wireless communication system
A method for and apparatus for performing an initial access procedure in a wireless communication system is provided. A wireless device detects a discontinuous transmission (DTX) cell that operates in a discontinuous transmission (DTX) state by receiving a discovery signal from the DTX cell; transmits an initial request message to the DTX cell to request the DTX cell to transition from the DTX state to a continuous transmission (TX) state.
1. A method for performing a measurement to discover small cells in a wireless communication system, the method comprising:
performing, by a user equipment, a measurement by using a first type signal;
receiving, by the user equipment, a configuration on a second type signal indicating a periodicity and an offset of the second type signal, wherein the second type signal is a discovery signal; and
performing, by the user equipment, a discovery signal-based Radio Resource Management (RRM) measurement by using the second type signal,
wherein the second type signal comprises a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Cell-specific Reference Signal (CRS) received within a predefined duration,
wherein the offset of the second type signal is in a number of subframes,
wherein the predefined duration for receiving all of the PSS, the SSS, and the CRS is set to 6 milliseconds,
wherein the periodicity for receiving all of the PSS, the SSS, and the CRS is set to 40 milliseconds or 80 milliseconds,
wherein the received CRS is not used for a data demodulation,
wherein the second type signal is received only from a secondary cell configured to support on/off operation, and
wherein the second type signal is received when the secondary cell is in an off-state.
2. The method of claim 1 , wherein the configuration is received via a higher layer signaling.
3. A user equipment (UE) for performing a measurement to discover small cells in a mobile communication system, the UE comprising:
a transceiver configured to receive a radio signal; and
a processor configured to:
perform a measurement by using a first type signal,
control the transceiver to receive a configuration on a second type signal indicating a periodicity and an offset of the second type signal,
wherein the second type signal is a discovery signal, and
perform a discovery signal-based Radio Resource Management (RRM) measurement by using the second type signal,
wherein the second type signal comprises a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Cell-specific Reference Signal (CRS) received within a predefined duration,
wherein the offset of the second type signal is in a number of subframes,
wherein the predefined duration for receiving all of the PSS, the SSS, and the CRS is set to 6 milliseconds,
wherein the periodicity for receiving all of the PSS, the SSS, and the CRS is set to 40 milliseconds or 80 milliseconds,
wherein the received CRS is not used for a data demodulation,
wherein the second type signal is received only from a secondary cell configured to support on/off operation, and
wherein the second type signal is received when the secondary cell is in an off-state.
4. The UE of claim 3 , wherein the configuration is received via a higher layer signaling.
5. A method for performing a measurement to discover small cells in a wireless communication system, the method comprising:
performing, by a user equipment, a measurement using a signal received via a higher layer signaling for a primary cell (PCell);
receiving, by the user equipment, parameters including a periodicity and a predefined duration of a discovery signal for a secondary cell (SCell),
wherein the discovery signal includes a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Cell-specific Reference Signal (CRS); and
performing, by the user equipment, a discovery signal-based Radio Resource Management (RRM) measurement using the discovery signal,
wherein the predefined duration for receiving all of the PSS, the SSS, and the CRS is set to 6 milliseconds,
wherein the periodicity for receiving all of the PSS, the SSS, and the CRS is set to 40 milliseconds or 80 milliseconds,
wherein the received CRS is not used for a data demodulation,
wherein the discovery signal is received only from a secondary cell configured to support on/off operation, and
wherein the discovery signal is received when the secondary cell is in an off-state.