Method for receiving control information in orthogonal frequency division multiplexing system of mobile communication system

Abstract

The present invention relates to receiving control information in an orthogonal frequency division multiplexing (OFDM) system of a mobile communication system. The present invention includes receiving information related to a number of OFDM symbols in a subframe for receiving first control information, receiving information related to a number of OFDM symbols in the subframe for receiving second control information, decoding the first control information according to the received information related to the number of OFDM symbols in the subframe for receiving the first control information, and decoding the second control information according to the received information related to the number of OFDM symbols in the subframe for receiving the second control information, wherein the number of OFDM symbols for receiving the first control information is less than or equal to the number of OFDM symbols for receiving the second control information.

What is claimed is: 
     
       1. A method of transmitting downlink control channels at a base station of an orthogonal frequency division multiplexing (OFDM) system, the method comprising:
 transmitting first information indicating related to a size m of a first region through a broadcast channel, wherein the first region is defined by m OFDM symbol(s) starting from a beginning of a subframe and the first region is used for first control channels that carry hybrid automatic repeat request (HARQ) ACK/NACKs; 
 transmitting second information indicating related to a size n of a second region through a physical control format indicator channel (PCFICH), wherein the second region is defined by n OFDM symbol(s) starting from the beginning of the subframe and the second region is used for second control channels that carry downlink control information; and 
 transmitting the HARQ ACK/NACKs and the downlink control information through the first control channels and second control channels, respectively, 
 wherein first resources for the first control channels are identified from the first information, and second resources for the second control channels are identified from remaining resources excluding other than the first resources within the second region, and 
 wherein the second control channels are physical downlink control channels (PDCCHs). 
 
     
     
       2. The method of  claim 1 , wherein the size n is configured to be equal to or greater than the size m such that n≧m. 
     
     
       3. A method of receiving downlink control channels at a mobile terminal of an orthogonal frequency division multiplexing (OFDM) system, the method comprising:
 receiving first information indicating related to a size m of a first region through a broadcast channel, wherein the first region is defined by m OFDM symbol(s) starting from a beginning of a subframe and the first region is used for first control channels that carry hybrid automatic repeat request (HARQ) ACK/NACKs; 
 receiving second information indicating related to a size n of a second region through a physical control format indicator channel (PCFICH), wherein the second region is defined by n OFDM symbol(s) starting from the beginning of the subframe and the second region is used for second control channels that carry downlink control information; and 
 receiving the HARQ ACK/NACKs and the downlink control information through the first control channels and second control channels, respectively, 
 wherein first resources for the first control channels are identified from the first information, and second resources for the second control channels are identified from remaining resources excluding other than the first resources within the second region, and 
 wherein the second control channels are physical downlink control channels (PDCCHs). 
 
     
     
       4. The method of  claim 3 , wherein the size n is configured to be equal to or greater than the size m such that n≧m. 
     
     
       5. The method of  claim 3 , further comprising:
 performing operations in accordance with one of the second control channels received through the second region that is designated to the mobile terminal. 
 
     
     
       6. A base station used in an orthogonal frequency division multiplexing (OFDM) system, the base station comprising:
 a radio frequency unit; and 
 a processor, 
 wherein the processor is configured to: 
 transmit first information indicating related to a size m of a first region through a broadcast channel, wherein the first region is defined by m OFDM symbol(s) starting from beginning of a subframe and the first region is used for first control channels that carry hybrid automatic repeat request (HARQ) ACK/NACKs; 
 transmit second information indicating related to a size n of a second region through a physical control format indicator channel (PCFICH), wherein the second region is defined by n OFDM symbol(s) starting from the beginning of the subframe and the second region is used for second control channels that carry downlink control information; and 
 transmit the HARQ ACK/NACKs and the downlink control information through the first control channels and second control channels, respectively, 
 wherein first resources for the first control channels are identified from the first information, and second resources for the second control channels are identified from remaining resources excluding other than the first resources within the second region, and 
 wherein the second control channels are physical downlink control channels (PDCCHs). 
 
     
     
       7. The base station of  claim 6 , wherein the size n is configured to be equal to or greater than the size m such that n≧m. 
     
     
       8. A mobile terminal used in an orthogonal frequency division multiplexing (OFDM) system, the mobile terminal comprising:
 a radio frequency unit; and 
 a processor, 
 wherein the processor is configured to: receive first information indicating related to a size m of a first region through a broadcast channel, wherein the first region is defined by m OFDM symbol(s) starting from a beginning of a subframe and the first region is used for first control channels that carry hybrid automatic repeat request (HARQ) ACK/NACKs; 
 receive second information indicating related to a size n of a second region through a physical control format indicator channel (PCFICH), wherein the second region is defined by n OFDM symbol(s) starting from the beginning of the subframe and the second region is used for second control channels that carry downlink control information; and 
 receive the HARQ ACK/NACKs and the downlink control information through the first control channels and second control channels, respectively, 
 wherein first resources for the first control channels are identified from the first information, and second resources for the second control channels are identified from remaining resources excluding other than the first resources within the second region, and 
 wherein the second control channels are physical downlink control channels (PDCCHs). 
 
     
     
       9. The mobile terminal of  claim 8 , wherein the size n is configured to be equal to or greater than the size m such as that n≧m. 
     
     
       10. The mobile terminal of  claim 8 , wherein the processor is further configured to:
 perform operations in accordance with one of the second control channels received through the second region that is designated to the mobile terminal.