Method of comparing state variable or packet sequence number for a wireless communications system and related apparatus

1. A method of comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic for a receiving terminal of a wireless communications system, the receiving terminal operating in an unacknowledged mode and supporting a duplicate avoidance and reordering function, hereinafter called DAR function, the method comprising:

establishing a DAR entity when the DAR function is initiated;

providing a reception buffer for storing packets received by the receiving terminal;

the receiving terminal determining a sequence number range of a receiving window and using a minimum sequence number of the receiving window as a modulus base for the modulus arithmetic when the DAR function is configured; and

the receiving terminal providing the modulus base for the DAR entity and the reception buffer to use when the DAR function is configured;

wherein determining the sequence number range of the receiving window comprises determining the sequence number range of the receiving window according to a window size of the receiving window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received by the DAR entity.

2. The method of claim 1 , wherein the minimum sequence number of the receiving window is derived from the state variable subtracting the window size of the receiving window plus a predetermined value.

3. The method of claim 2 , wherein the predetermined value is 1.

4. A communications device of a wireless communications system for accurately comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic to avoid comparison errors, the communications device operating in an unacknowledged mode and supporting a duplicate avoidance and reordering function, hereinafter called DAR function, the communications device comprising:

a control circuit for realizing functions of the communications device;

a central processing unit coupled to the control circuit for executing a program code to operate the control circuit;

a memory coupled to the central processing unit for storing the program code; and

a reception buffer installed in the memory, for storing packets received by the communications device;

wherein the program code comprises:

establishing a DAR entity when the DAR function is initiated;

determining a sequence number range of a receiving window and using a minimum sequence number of the receiving window as a modulus base for the modulus arithmetic when the DAR function is configured; and

providing the modulus base for the DAR entity and the reception buffer to use;

wherein determining the sequence number range of the receiving window comprises determining the sequence number range of the receiving window according to a window size of the receiving window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received by the DAR entity.

5. The communications device of claim 4 , wherein the minimum sequence number of the receiving window is derived from the state variable subtracting the window size of the receiving window plus a predetermined value.

6. The communications device of claim 5 , wherein the predetermined value is 1.

7. A method of comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic for a receiving terminal of a wireless communications system, the receiving terminal operating in an unacknowledged mode and supporting an out of sequence packet delivery function, the method comprising:

the receiving terminal determining a sequence number range of a storage window and using a minimum sequence number of the storage window as a modulus base for the modulus arithmetic when the out of sequence packet delivery function is configured; and

wherein determining the sequence number range of the storage window comprises determining the sequence number range of the storage window according to a window size of the storage window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received under the out of sequence packet delivery function.

8. The method of claim 7 , wherein the minimum sequence number of the storage window is derived from the state variable subtracting the window size of the storage window plus a predetermined value.

9. The method of claim 8 , wherein the predetermined value is 1.

10. The method of claim 7 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.

11. A communications device of a wireless communications system for accurately comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic to avoid comparison errors, the communications device operating in an unacknowledged mode and supporting an out of sequence packet delivery function, the communications device comprising:

a control circuit for realizing functions of the communications device;

a central processing unit coupled to the control circuit for executing a program code to operate the control circuit;

a memory coupled to the central processing unit for storing the program code; and

a reception buffer installed in the memory, for storing packets received by the communications device;

wherein the program code comprises:

determining a sequence number range of a storage window and using a minimum sequence number of the storage window as a modulus base for the modulus arithmetic when the out of sequence packet delivery function is configured; and

wherein determining the sequence number range of the storage window comprises determining the sequence number range of the storage window according to a window size of the storage window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received under the out of sequence packet delivery function.

12. The communications device of claim 11 , wherein the minimum sequence number of the storage window is derived from the state variable subtracting the window size of the storage window plus a predetermined value.

13. The communications device of claim 12 , wherein the predetermined value is 1.

14. The communications device of claim 11 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.

15. A method of comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic for a receiving terminal of a wireless communications system, the receiving terminal operating in an unacknowledged mode and supporting an out of sequence packet delivery function and a duplicate avoidance and reordering function, hereinafter called DAR function, the method comprising:

providing a reception buffer for storing packets received by the receiving terminal; and

the receiving terminal using a sequence number of the latest packet received by the reception buffer plus a predetermined value as a modulus base for the modulus arithmetic when neither the out of sequence packet delivery function nor the DAR function is configured.

16. The method of claim 15 , wherein the predetermined value is 1.

17. The method of claim 15 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.

18. A communications device of a wireless communications system for accurately comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic to avoid comparison errors, the communications device operating in an unacknowledged mode and supporting an out of sequence packet delivery function and a duplicate avoidance and reordering function, hereinafter called DAR function, the communications device comprising:

a control circuit for realizing functions of the communications device;

a central processing unit coupled to the control circuit for executing a program code to operate the control circuit;

a memory coupled to the central processing unit for storing the program code; and

a reception buffer installed in the memory, for storing packets received by the communications device;

wherein the program code comprises:

using a sequence number of the latest packet received by the reception buffer plus a predetermined value as a modulus base for the modulus arithmetic when neither the out of sequence packet delivery function nor the DAR function is configured.

19. The communications device of claim 18 , wherein the predetermined value is 1.

20. The communications device of claim 18 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.

21. A method of comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic for a receiving terminal of a wireless communications system, the receiving terminal operating in an unacknowledged mode and supporting an out of sequence packet delivery function and a duplicate avoidance and reordering function, hereinafter called DAR function, the method comprising:

establishing a DAR entity when the DAR function is initiated; providing a reception buffer for storing packets received by the receiving terminal;

the receiving terminal determining a sequence number range of a receiving window and using a minimum sequence number of the receiving window as a modulus base for the modulus arithmetic when the DAR function is configured;

the receiving terminal providing the modulus base for the DAR entity and the reception buffer to use when the DAR function is configured;

the receiving terminal determining a sequence number range of a storage window and using a minimum sequence number of the storage window as the modulus base when the out of sequence packet delivery function is configured; and

the receiving terminal using a sequence number of the latest packet received by the reception buffer plus a first predetermined value as the modulus base when neither the out of sequence packet delivery function nor the DAR function is configured.

22. The method of claim 21 , wherein determining the sequence number range of the receiving window comprises determining the sequence number range of the receiving window according to a window size of the receiving window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received by the DAR entity.

23. The method of claim 22 , wherein the minimum sequence number of the receiving window is derived from the state variable subtracting the window size of the receiving window plus a second predetermined value.

24. The method of claim 23 , wherein the second predetermined value is 1.

25. The method of claim 21 , wherein determining the sequence number range of the storage window comprises determining the sequence number range of the storage window according to a window size of the storage window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received under the out of sequence packet delivery function.

26. The method of claim 25 , wherein the minimum sequence number of the storage window is derived from the state variable subtracting the window size of the storage window plus a second predetermined value.

27. The method of claim 26 , wherein the first predetermined value is 1.

28. The method of claim 21 , wherein the first predetermined value is 1.

29. The method of claim 21 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.

30. A communications device of a wireless communications system for accurately comparing a state variable or a sequence number corresponding to a packet with modulus arithmetic to avoid comparison errors, the communications device operating in an unacknowledged mode and supporting an out of sequence packet delivery function and a duplicate avoidance and reordering function, hereinafter called DAR function, the communications device comprising:

a control circuit for realizing functions of the communications device;

a central processing unit coupled to the control circuit for executing a program code to operate the control circuit;

a memory coupled to the central processing unit for storing the program code; and

a reception buffer installed in the memory, for storing packets received by the communications device;

wherein the program code comprises:

establishing a DAR entity when the DAR function is initiated;

determining a sequence number range of a receiving window and using a minimum sequence number of the receiving window as a modulus base for the modulus arithmetic when the DAR function is configured;

providing the modulus base for the DAR entity and the reception buffer to use when the DAR function is configured;

determining a sequence number range of a storage window and using a minimum sequence number of the storage window as the modulus base when the out of sequence packet delivery function is configured; and

using a sequence number of the latest packet received by the reception buffer plus a first predetermined value as the modulus base when neither the out of sequence packet delivery function nor the DAR function is configured.

31. The communications device of claim 30 , wherein determining the sequence number range of the receiving window comprises determining the sequence number range of the receiving window according to a window size of the receiving window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received by the DAR entity.

32. The communications device of claim 31 , wherein the minimum sequence number of the receiving window is derived from the state variable subtracting the window size of the receiving window plus a second predetermined value.

33. The communications device of claim 32 , wherein the second predetermined value is 1.

34. The communications device of claim 30 , wherein determining the sequence number range of the storage window comprises determining the sequence number range of the storage window according to a window size of the storage window and a state variable corresponding to a maximum sequence number of the sequence numbers that have been received under the out of sequence packet delivery function.

35. The communications device of claim 34 , wherein the minimum sequence number of the storage window is derived from the state variable subtracting the window size of the storage window plus a second predetermined value.

36. The communications device of claim 35 , wherein the second predetermined value is 1.

37. The communications device of claim 30 , wherein the first predetermined value is 1.

38. The communications device of claim 30 , wherein the out of sequence packet delivery function is an out of sequence service data unit delivery function, known as out of sequence SDU delivery function.