Methods and apparatus for random chip delay access priority in a communications system

• US 6,674,765 B1
• Filed: 10/14/1998
• Issued: 01/06/2004
• Est. Priority Date: 05/22/1998
• Status: Expired due to Term

• Current Assignee: Provenance Asset Group LLC
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Zhang, Qinqing, Yue, On-Ching, Chuah, Mooi Choo
• Primary Examiner(s): PHAN, MAN U
• Application Number:
  US09/172,493
• Time in Patent Office: 1,910 Days
• Field of Search: 370/252, 370/253, 370/342, 370/328, 370/348, 370/448, 370/458, 370/461, 370/466, 370/335, 370/443, 370/322, 370/233, 370/235, 375/143, 375/245, 375/152, 375/207, 375/208, 455/466, 455/512, 455/515, 455/509, 455/517, 455/450, 455/510, 455/464
• US Class Current: 370/458
• CPC Class Codes: H04W 74/0875 with assigned priorities based access
• CPC Class Codes: H04W 84/04 Large scale networks; Deep hierarchical networks
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

The present invention provides methods and apparatus for providing access priority in a MAC protocol of a communications system such as, for example, with respect to UMTS RACH. Particularly, the invention introduces several access priority methodologies including: (i) random chip delay access priority (RCDAP); (ii) random backoff based access priority (RBBAP); (iii) variable logical channel based access priority (VLCAP); (iv) UMTS-specific variable logical channel based access priority (VLCAP′); (v) probability based access priority (PBAP); and (vi) retransmission based access priority (REBAP). Each methodology associates some parameter or parameters to access priority classes in order to influence the likelihood of a remote terminal completing a successful access request to a base station.

Claims

1. A method of access priority control in a remote terminal of a wireless communications system, the method comprising the steps of:

selecting a chip delay to be associated with an access request signal from among different chip delays respectively associated with pre-established access priority classes; and

transmitting the access request signal on a selected logical access channel to a base station in the wireless communications system.

2. The method of claim 1, wherein a higher access priority class is associated with a lower chip delay.

3. The method of claim 1, wherein a lower access priority class is associated with a higher chip delay.

4. The method of claim 1, further comprising the step of determining whether the access request signal has been received by the base station.

5. The method of claim 4, wherein the determining step includes monitoring for receipt of an acknowledgement signal from the base station indicating receipt of the access request signal.

6. The method of claim 4, further including the step of incrementing a variable indicative of a number of access request transmission attempts made to the base station when the determining step indicates that a preceding access request signal has not been received by the base station.

7. The method of claim 6, further including the step of comparing the access request transmission attempt variable to a value indicative of a maximum allowable number of transmission attempts, the maximum allowable transmission attempt value being a function of the pre-established access priority classes.

8. The method of claim 7, further including the step of dropping the access request when the access request transmission attempt variable is greater than the maximum allowable transmission attempt value.

9. The method of claim 8, further comprising the step of performing a backoff process when the access request transmission attempt variable is not greater than the maximum allowable transmission attempt value.

10. The method of claim 9, further comprising the step of repeating the chip delay selection step and transmission step, after the backoff process, in order to transmit another access request.

11. The method of claim 1, wherein the preestablished access priority classes relate to one of service level, message content, and delay requirements.

12. The method of claim 1, further comprising the step of receiving the chip delays from the base station.

13. The method of claim 1, wherein the chip delays are associated with random distributions of chip delays which are respectively associated with the pre-established access priority classes and the chip delay to be associated with the access request signal is selected from one of the distributions.

14. The method of claim 1, further including the step of selecting the logical access channel for transmission from among a set of logical access channels, the set including a quantity of logical access channels, the quantity being a function of the preestablished access priority classes.

15. The method of claim 1, further including the step of selecting the logical access channel or transmission by selecting a preamble and a time offset from a set of preambles and a set of time offsets associated with a plurality of logical access channels.

16. The method of claim 15, wherein the set of time offsets are a function of the pre-established access priority classes.

17. The method of claim 1, wherein the wireless communications system is a UMTS.

18. The method of claim 1, wherein the selected logical access channel is a RACH.

19. A method of access priority control in a base station of a wireless communications system, the method comprising the steps of:

broadcasting chip delays respectively associated with pre-established access priority classes; and

transmitting an acknowledgement signal to a remote terminal in the wireless communications system from which an access request signal having a chip delay associated therewith has been received.

20. Apparatus for access priority control in a wireless communications system, comprising:

a remote terminal configured for selecting a chip delay to be associated with an access request signal from different chip delays respectively associated with pre-established access priority classes and for transmitting the access request signal on a selected logical access channel to a base station in the wireless communications system.

21. The apparatus of claim 20, wherein the remote terminal is a mobile terminal.

22. The apparatus of claim 20, wherein the remote terminal is a fixed terminal.

23. The apparatus of claim 20, wherein a higher access priority class is associated with a lower chip delay.

24. The apparatus of claim 20, wherein a lower access priority class is associated with a higher chip delay.

25. The apparatus of claim 20, wherein the remote terminal determines whether the access request signal has been received by the base station.

26. The apparatus of claim 25, wherein the remote terminal performs the determining step by monitoring for receipt of an acknowledgement signal from the base station indicating receipt of the access request signal.

27. The apparatus of claim 25, wherein the remote terminal increments a variable indicative of a number of access request transmission attempts made to the base station when the determining step indicates that a preceding access request signal has not been received by the base station.

28. The apparatus of claim 27, further wherein the remote terminal compares the access request transmission attempt variable to a value indicative of a maximum allowable number of transmission attempts, the maximum allowable transmission attempt value being a function of the pre-established access priority classes.

29. The apparatus of claim 28, further wherein the remote terminal drops the access request when the access request transmission attempt variable is greater than the maximum allowable transmission attempt value.

30. The apparatus of claim 29, further wherein the remote terminal performs a backoff process when the access request transmission attempt variable is not greater than the maximum allowable transmission attempt value.

31. The apparatus of claim 30, further wherein the remote terminal repeats the chip delay selection step and transmission step, after the backoff process, in order to transmit another access request.

32. The apparatus of claim 20, wherein the pre-established access priority classes relate to one of service level, message content, and delay requirements.

33. The apparatus of claim 20, further wherein the remote terminal receives the chip delays from the base station.

34. The apparatus of claim 20, wherein the chip delays are associated with random distributions of chip delays which are respectively associated with the pre-established access priority classes and the chip delay to be associated with the access request signal is selected from one of the distributions.

35. The apparatus of claim 20, further wherein the remote terminal selects the logical access channel for transmission from among a set of logical access channels, the set including a quantity of logical access channels, the quantity being a function of the pre-established access priority classes.

36. The apparatus of claim 20, further wherein the remote terminal selects the logical access channel for transmission by selecting a preamble and a time offset from a set of preambles and a set of time offsets associated with a plurality of logical access channels.

37. The apparatus of claim 36, wherein the set of time offsets are a function of the pre-established access priority classes.

38. The apparatus of claim 20, wherein the wireless communications system is a UMTS.

39. The apparatus of claim 20, wherein the selected logical access channel is a RACH.

40. Apparatus for access priority control in a wireless communications system, comprising:

a base station configured for broadcasting chip delays respectively associated with pre-established access priority classes and for transmitting an acknowledgement signal to a remote terminal in the wireless communications system from which an access request signal having a chip delay associated therewith has been received.