Method and apparatus for allocating bandwidth in wideband wireless communication system

1. A method for allocating a bandwidth in a wideband wireless communication system, the method comprising:

allocating a bandwidth to an uplink burst area in accordance with a bandwidth request received from at least one terminal;

determining whether a preemptive grant bandwidth allocation is enabled or not;

determining a preemptive grant terminal if the preemptive grant bandwidth allocation is enabled; and

allocating a preemptive grant bandwidth within a residual bandwidth of the uplink burst area to the determined preemptive grant terminal,

wherein the step of determining whether a preemptive grant bandwidth allocation is enabled or does not comprise:

calculating a size of the residual bandwidth except the bandwidth allocated to the uplink burst area; and

determining that the preemptive grant bandwidth allocation is enabled if the size of the residual bandwidth is more than a size of a reference bandwidth.

2. The method of claim 1 , further comprising:

transmitting an uplink MAP containing a bandwidth allocation information about the uplink burst area and a preemptive grant bandwidth allocation information containing a terminal identification information about the determined preemptive grant terminal and a preemptive grant bandwidth information.

3. The method of claim 2 , further comprising:

receiving data from the determined preemptive grant terminal at next frame to the frame containing the uplink MAP.

4. The method of claim 1 , wherein the step of determining that the preemptive grant bandwidth allocation is enabled comprises:

determining that the preemptive grant bandwidth allocation is enabled if the size of the residual bandwidth is more than a size of a bandwidth request header.

5. The method of claim 1 , wherein the determination of the preemptive grant terminal is performed based on at least one of user grade information, usage state and usage period information for preemptive grant bandwidth, current service class information, ARQ response processing state information, and ranging request state information.

6. The method of claim 1 , prior to the step of allocating a bandwidth to an uplink burst area, further comprising:

transmitting a bandwidth allocation Information Element (IE) for a bandwidth request header in accordance with a ranging request received from at least one terminal; and

receiving a bandwidth request corresponding to the bandwidth allocation Information Element (IE) for the bandwidth request header.

7. The method of claim 6 , wherein the preemptive grant terminal is selected from among terminals which are not related to the bandwidth allocation Information Element (IE) for the bandwidth request header.

8. The method of claim 1 , after the step of determining whether a preemptive grant bandwidth allocation is enabled or not, further comprising:

transmitting an uplink MAP which is generated based on a bandwidth being allocated to the uplink burst area.

9. An apparatus for allocating a bandwidth in a wideband wireless communication system, the apparatus comprising:

a preemptive grant determiner for determining whether a preemptive grant bandwidth allocation is enabled or not, based on a size of a residual bandwidth other than a bandwidth allocated to an uplink burst area;

a terminal determiner for determining a preemptive grant terminal to which the preemptive grant bandwidth is allocated;

a preemptive grant bandwidth allocator for allocating the preemptive grant bandwidth to the preemptive grant terminal, using the residual bandwidth; and

a scheduler for generating an uplink MAP containing a bandwidth allocation information about the uplink burst area and a preemptive grant bandwidth allocation information,

wherein the preemptive grant determiner determines that the preemptive grant bandwidth allocation is enabled if the size of the residual bandwidth is more than a size of a reference bandwidth.

10. The apparatus of claim 9 , wherein the terminal determiner determines the preemptive grant terminal based on at least one of user grade information, usage state and usage period information for preemptive grant bandwidth, current service class information, ARQ response processing state information, and ranging request state information.

11. The apparatus of claim 9 , wherein the preemptive grant bandwidth allocator generates the preemptive grant bandwidth allocation information containing a terminal identification information about the determined preemptive grant terminal and a preemptive grant bandwidth information.

12. The apparatus of claim 9 , wherein the terminal determiner determines a terminal which is not included in the bandwidth information for a bandwidth request header, as the preemptive grant terminal.

13. The apparatus of claim 9 , wherein the terminal determiner determines a terminal which transmits data of a specific service class through an uplink burst which is allocated to a former uplink frame, as the preemptive grant terminal.

14. The apparatus of claim 9 , wherein the bandwidth allocated to the uplink burst area is a bandwidth which is allocated in response to a bandwidth request from a former granted terminal.

15. The apparatus of claim 9 , wherein the preemptive grant determiner determines that the preemptive grant bandwidth allocation is enabled if the size of the residual bandwidth is more than a size of a bandwidth request header.

16. The apparatus of claim 9 , wherein the scheduler generates the uplink MAP containing the bandwidth allocation information about the uplink burst area if the preemptive grant determiner determines that the preemptive grant bandwidth allocation is not enabled.