Method for setting up carrier in carrier aggregation system and apparatus required for same
The present invention relates to a wireless communication system. Specifically, the invention relates to a method for configuring a component carrier at a base station in a wireless communication system, comprising the steps of determining whether initial access is permitted to a user equipment with respect to a downlink component carrier; and transmitting a synchronization channel signal and a broadcast channel signal to at least one user equipment via the downlink component carrier, wherein the initial access permission is applied to said at least one user equipment by modifying at least one of the synchronization channel signal and the broadcast channel signal.
1. A method for configuring a component carrier at a base station in a wireless communication system supporting carrier aggregation, the method comprising:
configuring a downlink component carrier among a plurality of component carriers as a non-backward compatible component carrier,
wherein an initial access for the non-backward compatible component carrier by an evolved user equipment (UE) is permitted and an initial access for the non-backward compatible component carrier by an legacy UE is not permitted;
transmitting a synchronization channel and a broadcast channel to at least one UE, via the non-backward compatible downlink component carrier,
where the synchronization channel includes a primary synchronization channel and a secondary synchronization channel;
receiving an uplink signal from the evolved UE via an uplink component carrier linked to the non-backward compatible component carrier; and
receiving an uplink signal from the legacy UE via an uplink component carrier linked to a backward compatible downlink component carrier where the initial access by the legacy UE is permitted,
wherein the broadcast channel transmitted via the non-backward compatible component carrier is modified from a broadcast channel transmitted via the backward compatible downlink component carrier, and
wherein, for the non-backward compatible downlink component carrier, an orthogonal frequency division multiplexing (OFDM) symbol for the primary synchronization channel is followed by an OFDM symbol for the secondary synchronization channel in a subframe, to restrict the initial access for the non-backward compatible downlink component carrier by the legacy UE.
2. The method of claim 1 , wherein the transmitting the synchronization channel and the broadcast channel comprises scrambling segment 1 on the basis of segment 2 in a secondary synchronization channel into which the segment 1 and the segment 2 are mapped.
3. The method of claim 1 , wherein the initial access permission is applied by modifying a phase of a signal transmitted through the synchronization channel.
4. The method of claim 1 , wherein the transmitting the synchronization channel and the broadcast channel comprises modifying a location in a time domain of the broadcast channel.
5. The method of claim 1 , wherein the transmitting the synchronization channel and the broadcast channel comprises varying scrambling applied to a message of the broadcast channel.
6. The method of claim 1 , wherein the transmitting the synchronization channel and the broadcast channel comprises varying a CRC mask applied to cyclic redundancy check (CRC) of the broadcast channel.
7. A base station configured to perform a method for configuring a component carrier and to support carrier aggregation in a wireless communication system, the base station comprising:
a radio frequency (RF) unit configured to transmit and receive a radio signal to and from a user equipment (UE);
a memory for storing information transmitted to and received from the UE and a parameter required for an operation of the base station; and
a processor connected with the RF unit and the memory and configured to control the RF unit and the memory for the operation of the base station,
wherein the processor is adapted to:
configure a downlink component carrier among a plurality of component carriers as a non-backward compatible component carrier,
wherein an initial access for the non-backward compatible component carrier by an evolved user equipment (UE) is permitted and an initial access for the non-backward compatible component carrier by an legacy UE is not permitted,
transmit a synchronization channel and a broadcast channel to at least one UE, via the non-backward compatible downlink component carrier,
where the synchronization channel includes a primary synchronization channel and a secondary synchronization channel,
receive an uplink signal from the evolved UE via an uplink component carrier linked to the non-backward compatible component carrier, and
receive an uplink signal from the legacy UE via an uplink component carrier linked to a backward compatible downlink component carrier where the initial access by the legacy UE is permitted,
wherein the broadcast channel transmitted via the non-backward compatible component carrier is modified from a broadcast channel transmitted via the backward compatible downlink component carrier, and
wherein, for the non-backward compatible downlink component carrier, an orthogonal frequency division multiplexing (OFDM) symbol for the primary synchronization channel is followed by an OFDM symbol for the secondary synchronization channel in a subframe, to restrict the initial access for the non-backward compatible downlink component carrier by the legacy UE.