Method and apparatus for transmitting scheduling request using contention-based resources in wireless communication system

1. A method for transmitting a scheduling request (SR) at in a wireless communication system, the method performed by a first user equipment (UE) and comprising:

receiving information related to a resource for the SR from a base station (BS);

transmitting the SR to the BS over a control channel using the resource for the SR;

transmitting a first buffer status report (BSR) to the BS over a data channel using a first uplink (UL) contention-based resource without receiving an UL grant for the first BSR,

receiving a first UL grant for the first BSR from the BS if the first UL contention-based resource and a second UL contention-based resource are identical; and

retransmitting the first BSR to the BS based on the received first UL grant,

wherein the second UL contention-based resource is used by the BS to receive a second BSR from a second UE over a data channel without transmitting an UL grant for the second BSR, and

wherein the first UL contention-based resource is determined based on at least the resource for the SR or an identifier of the first UE.

2. The method according to claim 1 , further comprising:

receiving a second UL grant from the BS if the first UL contention-based resource and the second UL contention-based resource are different; and

transmitting data based on the received second UL grant.

3. The method according to claim 1 , further comprising receiving the first UL contention-based resource based on an index of the resource for the SR.

4. The method according to claim 3 , wherein:

an index of the first UL contention-based resources is determined as (index of the resource for the SR) mod N;

mod is a modulo operation; and

N is a number of contention-based resources contained in one contention-based UL zone.

5. The method according to claim 3 , wherein the index of the resource for the SR is a physical index of an UL resource through which the SR is transmitted.

6. The method according to claim 3 , further comprising:

receiving a predetermined logical index from the BS,

wherein the index of the resource for the SR is the predetermined logical index mapped to a physical index of an UL resource through which the SR is transmitted.

7. The method according to claim 3 , wherein:

an index of the first UL contention-based resources is determined as (first UE ID) mod X;

mod is a modulo operation; and

X is a number of contention-based resources contained in one contention-based UL zone.

8. A method for receiving a scheduling request (SR) in a wireless communication system, the method performed by a base station (BS) and comprising:

transmitting information related to a resource for the SR to a first user equipment (UE);

receiving the SR over a control channel from the first UE;

receiving a first buffer status report (BSR) from the BS over a data channel using a first uplink (UL) contention-based resource without transmitting an UL grant for the first BSR;

receiving a second BSR from a second UE using a second UL contention-based resource without transmitting an UL grant for the second BSR;

transmitting a first UL grant to the first UE if the first UL contention-based resource and the second UL contention-based resource are identical; and

receiving the first BSR from the first UE based on the first UL grant,

wherein the first uplink contention-based resource is determined based on at least one of the resource for the SR or an identifier of the first UE.

9. The method according to claim 8 , further comprising:

transmitting a second UL grant to the first UE if the first UL contention-based resource and the second UL contention-based resource are different; and

receiving data from the first UE based on the first UL grant.

10. A first user equipment (UE) device for transmitting a scheduling request (SR) in a wireless communication system, the UE comprising:

a receiver configured to receive information;

a transmitter configured to transmit information; and

a processor configured to:

control the receiver to receive information related to a resource for the SR from a base station (BS);

control the transmitter to transmit the SR to the BS over a control channel using the resource for the SR;

control the transmitter to transmit a first buffer status report (BSR) to the BS over a data channel using a first uplink (UL) contention-based resource without receiving an UL grant for the first BSR;

control the receiver to receive a first UL grant for the first BSR from the BS if the first UL contention-based resource and a second UL contention-based resource are identical;

control the transmitter to retransmit the first BSR to the BS based on the received first UL grant,

wherein the second UL contention-based resource is a resource used by the BS to receive a second BSR from a second UE over a data channel without transmitting an UL grant for the second BSR, and

wherein the first UL contention-based resource is determined based on at least the resource for the SR or an identifier of the first UE.

11. The UE according to claim 10 , wherein the processor is further configured to control the receiver to receive the first UL contention-based resource based on an index of the resource for the SR.

12. The UE according to claim 11 , wherein the index of the resource for the SR is a physical index of an UL resource through which the SR is transmitted.

13. The UE according to claim 11 , wherein:

the processor is further configured to control the receiver to receive a predetermined logical index from the BS; and

the index of the resource for the SR is the predetermined logical index mapped to a physical index of an UL resource through which the SR is transmitted.

14. The UE according to claim 11 , wherein:

an index of the first UL contention-based resource is determined as (first UE ID) mod X;

mod is a modulo operation; and

X is a number of contention-based resources contained in one contention-based UL zone.

15. The UE according to claim 11 , wherein:

an index of the first UL contention-based resource is determined as (index of the resource for the SR) mod N;

mod is a modulo operation; and

N is a number of contention-based resources contained in one contention-based UL zone.

16. The UE according to claim 10 , wherein the processor is further configured to:

control the receiver to receive a second UL grant from the BS if the first UL contention-based resource and the second UL contention-based resource are different; and

control the transmitter to transmit data based on the received second UL grant.

17. A base station (BS) for receiving a scheduling request (SR), the BS comprising:

a transmitter configured to transmit information;

a receiver configured to receive information; and

a processor configured to:

control the transmitter to transmit information related to a resource for the SR to a first user equipment (UE);

control the receiver to receive the SR over a control channel from the first UE;

control the receiver to receive a first buffer status report (BSR) from the first UE over a data channel using a first uplink (UL) contention-based resource without transmitting an UL grant for the first BSR;

control the receiver to receive a second BSR from a second UE using a second UL contention-based resource without transmitting an UL grant for the second BSR;

control the transmitter to transmit a first UL grant to the first UE if the first UL contention-based resource and the second UL contention-based resource are identical; and

control the receiver to receive the first BSR from the first UE based on the first UL grant,

wherein the first uplink contention-based resource is determined based on at least the resource for the SR or an identifier of the first UE.

18. The BS according to claim 17 , wherein the processor is further configured to:

control the transmitter to transmit a second UL grant to the first UE if the first UL contention-based resource and the second UL contention-based resource are different; and

control the receiver to receive data from the first UE based on the first UL grant.