Buffer status reporting methods for machine type communication data transmission and related mobile communication devices

1. A mobile communications device for performing a buffer status reporting procedure, comprising:

a wireless module, performing wireless transmissions and receptions to and from a cellular station of a service network; and

a controller module, receiving machine type communication (MTC) data, and determining whether to trigger a buffer status report (BSR) to the cellular station via the wireless module according to a comparison result of the data size of the MTC data and a threshold value when the MTC data arrives at an empty transmission buffer of the mobile communications device,

wherein the controller module further determines whether to trigger the BSR according to a comparison result of the data size of the MTC data and an accumulated data size of the transmission buffer and the threshold value when the MTC data arrives at an empty transmission buffer of the mobile communications device, wherein the controller module triggers the BSR when a total amount of the data size of the MTC data and the accumulated data size of the transmission buffer is greater than the threshold value and the controller module further starts a timer when the data size of the MTC data is less than or equal to the threshold value, directs the timer to start a count when the total amount of the data size of the MTC data and the accumulated data size of the transmission buffer is less than or equal to the threshold value, and triggers the BSR when the count of the timer has expired.

2. The mobile communications device of claim 1 , wherein the controller module determines not to trigger the BSR when the data size of the MTC data is less than or equal to the threshold value, and determines to trigger the BSR when the data size of the MTC data is greater than the threshold value.

3. The mobile communications device of claim 1 , wherein the controller module further triggers the BSR when the count of the timer is expired.

4. The mobile communications device of claim 3 , wherein the controller module further resets the timer after the BSR has been triggered.

5. The mobile communications device of claim 1 , wherein the value of the threshold value and the count value of the timer are configured by an upper layer signaling of the mobile communications device.

6. The mobile communications device of claim 1 , wherein the controller module further receives a first message from the cellular station via the wireless module, prior to the triggering of the BSR and obtains the value of the threshold value and the count value of the timer from the first message.

7. The mobile communications device of claim 6 , wherein the controller module further transmits a second message to the cellular station, indicating to the cellular station that a transmission of small size data is being performed via the wireless module, prior to the reception of the first message from the cellular station, such that the cellular station transmits the first message comprising the value of the threshold value and the count value of the timer.

8. The mobile communications device of claim 1 , wherein the threshold value is configured as a predetermined ratio of the buffer size of the transmission buffer.

9. A buffer status reporting method for machine type communication (MTC) data for a mobile communications device with a wireless module, comprising:

receiving MTC data; and

determining whether to trigger a buffer status report (BSR) according to a comparison result of the data size of the MTC data and a threshold value when the MTC data arrives at an empty transmission buffer, and transmitting the BSR to the cellular station via the wireless module when determining to trigger the BSR,

wherein the method further comprises:

determining whether to trigger the BSR according to a comparison result of the data size of the MTC data and an accumulated data size of the transmission buffer and the threshold value when the MTC data arrives at an empty transmission buffer of the mobile communications device, wherein the BSR is triggered when a total amount of the data size of the MTC data and the accumulated data size of the transmission buffer is greater than the threshold value;

starting a timer when the data size of the MTC data is less than or equal to the threshold value;

directing the timer to count when the total amount of the data size of the MTC data and the accumulated data size of the transmission buffer is less than or equal to the threshold value; and

determining whether to trigger the BSR according to a determination of whether the count of the timer has expired.

10. The buffer status reporting method of claim 9 , wherein the step of determining whether to trigger the BSR further comprises:

determining not to trigger the BSR when the data size of the MTC data is less than or equal to the threshold value; and

determining to trigger the BSR when the data size of the MTC data is greater than the threshold value.

11. The buffer status reporting method of claim 9 , wherein the step of determining whether to trigger the BSR according to the determination of whether the count of the timer has expired further comprises:

determining to trigger the BSR when the count of the timer is expired.

12. The buffer status reporting method of claim 11 , further comprising:

resetting the timer after the BSR has been triggered.

13. The buffer status reporting method of claim 9 , wherein the value of the threshold value and the count value of the timer are configured by an upper layer signaling of the mobile communications device.

14. The buffer status reporting method of claim 9 , further comprising:

receiving a first message from the cellular station via the wireless module, prior to the triggering of the BSR and obtaining the value of the threshold value and the count value of the timer from the first message.

15. The buffer status reporting method of claim 14 , further comprising:

transmitting a second message to the cellular station, indicating to the cellular station that a transmission of small size data is being performed via the wireless module, prior to the reception of the first message from the cellular station, such that the cellular station transmits the first message comprising the value of the threshold value and the count value of the timer.

16. The buffer status reporting method of claim 9 , wherein the threshold value is configured as a predetermined ratio of the buffer size of the transmission buffer.

17. The buffer status reporting method of claim 9 , wherein the BSR is a regular BSR.

18. The buffer status reporting method of claim 9 , further comprising:

triggering a scheduling request (SR) procedure after the BSR has been triggered.