Method and apparatus for transmitting system information from a base station supporting an improved system

1. A method for transmitting system information from a base station that supports a legacy system and an improved system having one or more functions added to the legacy system, the method comprising:

transmitting a first broadcast channel, containing system information for supporting a user equipment for the legacy system, in a predetermined number of symbols that follow a synchronization channel in a first subframe of a radio frame containing a plurality of subframes; and

transmitting additional system information for supporting a user equipment for the improved system in a second subframe, other than the first subframe, from among the plurality of subframes,

wherein: the additional system information is contained in a second broadcast channel that is different from the first broadcast channel and transmitted in the second subframe; and the second broadcast channel is masked with a Cyclic Redundancy Check (CRC) that is different from a CRC applied to the first broadcast channel.

2. The method according to claim 1 , wherein a master information block in the first broadcast channel contains information that indicates presence of the second broadcast channel.

3. The method according to claim 1 , wherein: the plurality of subframes comprise ten subframes including subframe # 0 , which is a 0 th subframe, to subframe # 9 , which is a ninth subframe; the first subframe corresponds to subframe # 0 ; and the second subframe corresponds to subframe # 4 , # 5 , or # 9 .

4. The method according to claim 1 , wherein: the plurality of subframes comprise ten subframes including subframe # 0 , which is a 0 th subframe, to subframe # 9 , which is a ninth subframe;

each of the ten subframes includes two slots;

the first subframe corresponds to subframe # 0 ;

the second subframe corresponds to subframe # 5 ;

and the predetermined number of symbols correspond to four leading symbols of a rear slot among two slots included in subframe # 5 .

5. The method according to claim 1 , wherein the additional system information is contained in a system information block.

6. The method according to claim 5 , wherein a master information block in the first broadcast channel contains information that indicates presence of the additional system information.

7. The method according to claim 5 , wherein: the plurality of subframes comprise ten subframes including subframe #0, which is a 0 th subframe, to subframe # 9 , which is a ninth subframe;

the first subframe corresponds to subframe # 0 ; and

the second subframe corresponds to one of the ten subframes other than subframe # 0 .

8. The method according to claim 5 , wherein the system information block corresponds to system information block type 1 transmitted at an interval of 20 ms.

9. A base station that supports a legacy system and an improved system having one or more functions added to the legacy system, the base station comprising:

a transmitter configured to transmit a radio frame including a plurality of subframes; and

a processor configured to:

control the transmitter to transmit a first broadcast channel, containing system information for supporting a user equipment for the legacy system, in a predetermined number of symbols that follow a synchronization channel in a first subframe of the radio frame; and

control the transmitter to transmit additional system information for supporting a user equipment for the improved system in a second subframe, other than the first subframe, from among the plurality of subframes,

wherein: the additional system information is contained in a second broadcast channel that is different from the first broadcast channel and transmitted in the second subframe; and

the processor is further configured to mask the second broadcast channel with a Cyclic Redundancy Check (CRC) that is different from a CRC applied to the first broadcast channel.

10. The base station according to claim 9 , wherein a master information block in the first broadcast channel contains information that indicates presence of the second broadcast channel.

11. The base station according to claim 9 , wherein: the plurality of subframes comprise ten subframes including subframe # 0 , which is a 0 th subframe, to subframe # 9 , which is a ninth subframe; the first subframe corresponds to subframe # 0 ; and the second subframe corresponds to subframe # 4 , # 5 , or # 9 .

12. The base station according to claim 9 , wherein the plurality of subframes comprise ten subframes including subframe # 0 , which is a 0 th subframe, to subframe # 9 , which is a ninth subframe;

each of the ten subframes includes two slots;

the first subframe corresponds to subframe # 0 ;

the second subframe corresponds to subframe # 5 ; and

the processor is further configured to control the transmitter to transmit the second broadcast channel in four leading symbols of a rear slot among the slots included in subframe # 5 .

13. The base station according to claim 9 , wherein the processor is further configured to control the transmitter such that the additional system information is contained in a system information block.

14. The base station according to claim 13 , wherein a master information block in the first broadcast channel contains information that indicates presence of the additional system information.

15. The base station according to claim 13 , wherein:

the plurality of subframes comprise ten subframes including subframe # 0 , which is a 0 th subframe, to subframe # 9 , which is a ninth subframe;

the first subframe corresponds to subframe # 0 ; and

the second subframe corresponds to one of the ten subframes other than subframe # 0 .

16. The base station according to claim 13 , wherein:

the system information block corresponds to system information block type 1 ; and

the processor is further configured to control the transmitter to transmit the system information block type 1 at an interval of 20 ms.