Channel switching apparatus and method of a base station and channel switching apparatus and method of a terminal based on the cognitive radio system

A channel switching method performed by a base station in a cognitive radio system, wherein the base station allocates a slot for data exchange with each of a plurality of terminals in a frequency channel which is not used by an IU (incumbent user), and performs communication, the channel switching method comprising:

• transmitting a channel switching message for requesting to switch to a backup channel when a signal of the IU is sensed in the frequency channel;
• transmitting a beacon frame via the backup channel, wherein the beacon frame comprises allocation information about slots which are in a previous frequency channel and which are respectively allocated to each of the plurality of terminals, wherein the allocation information contains at least one of a modulation scheme, coding information and information about which slot is allocated to which terminal;
• and
• allocating the slot for data exchange with each of the plurality of terminals to the backup channel according to the allocation information, and communicating with each of the plurality of terminals via the backup channel.

A channel switching apparatus of a terminal in a cognitive radio system, wherein the terminal communicates with a base station via an allocated slot in a frequency channel which is not used by an IU (incumbent user), the channel switching apparatus comprising:

• a beacon frame receiving unit receiving a beacon frame via a backup channel, wherein the beacon frame comprises allocation information about the slot which is in a previous frequency channel and which is allocated to the terminal, when the beacon frame receiving unit recognizes that the frequency channel is unusable due to the IU, wherein the allocation information contains at least one of a modulation scheme, coding information and information about which slot is allocated to which terminal;
• an allocated slot detecting unit extracting the allocation information by decoding the beacon frame, and detecting the slot in the backup channel by using the extracted allocation information, wherein the slot is allocated to the terminal;
• and
• a backup channel communicating unit communicating with the base station via the detected slot.

A channel switching method performed by a terminal in a cognitive radio system, wherein the terminal communicates with a base station via an allocated slot in a frequency channel which is not used by an IU (incumbent user), the channel switching method comprising:

• receiving a beacon frame via a backup channel, wherein the beacon frame comprises allocation information about the slot which is in a previous frequency channel and which is allocated to the terminal, when the beacon frame receiving unit recognizes that the frequency channel is unusable due to the IU, wherein the allocation information contains at least one of a modulation scheme, coding information and information about which slot is allocated to which terminal;
• extracting the allocation information by decoding the beacon frame, and detecting the slot in the backup channel by using the extracted allocation information, wherein the slot is allocated to the terminal;
• and
• communicating with the base station via the detected slot.