Random Access Channel Protocol

• US 20080279213A1
• Filed: 12/17/2003
• Published: 11/13/2008
• Est. Priority Date: 12/17/2003
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Tong, Wen, Zhu, Peiying, Vvedenskaya, Nikita D., Fedortsov, Sergei P., Likhanov, Nikolai L.
• Granted Patent: US 7,924,866 B2
• Time in Patent Office: Days
• US Class Current: 370/458
• CPC Class Codes: H04L 12/40143 involving priority mechanisms hybrid switching fabrics H04L12/6402; intermediate storage or scheduling H04L49/90; time-division multiplex systems H04J3/00
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation

Abstract

The present invention provides an improved random access channel protocol, wherein different user elements may be associated with different priority levels. Based on relative priority, the user elements may have different probabilities for deciding when to retransmit a previously transmitted packet upon receiving information from an access point indicating that the packet needs to be retransmitted. A buffer is provided for storing a packet to transmit, and the buffer is associated with a stack counter, which is incremented or decremented to or from a nominal value to determine when to transmit or retransmit the packet stored in the buffer. Based on the relative priority, feedback information from the access point may cause the stack counter for a packet needing to be retransmitted to stay at the nominal value, wherein retransmission will occur at the next available time slot, or it may increase the stack counter by one or more levels.

Claims

1. A user element for facilitating random access communications comprising:

a) receive circuitry;

b) transmit circuitry; and

c) control circuitry associated with the receive and transmit circuitry and adapted to;

i) transmit a packet stored in a buffer to an access point during a time slot when a stack counter is a nominal value; and

ii) adjust the stack counter when feedback information received from the access point is indicative of the packet needing to be retransmitted, the feedback information sent to a plurality of user elements in a communication environment.

2. The user element of claim 1 wherein the control circuitry is further adapted to implement one of a plurality of random number generators to generate a random number, which determines a relative amount by which the stack counter is adjusted such that different user elements will have different priorities based on the one of the plurality of random number generators implemented.

3. The user element of claim 2 wherein the different ones of the plurality of random number generators have a different number of possible outcomes such that a relative priority is decreased as the number of possible outcomes is increased.

4. The user element of claim 2 wherein the control circuitry is further adapted to retransmit the packet at an increased power level when the feedback information is indicative of the packet needing to be retransmitted.

5. The user element of claim 1 wherein the control circuitry is further adapted to select channels from a plurality of channels to use for transmitting packets to the access point on a packet-by-packet basis and transmit the packets on the selected channels.

6. The user element of claim 1 wherein the feedback information is indicative of a relative number of successful channels in which packets were properly received to a relative number of unsuccessful channels in which packets were not properly received, and the control circuitry is adapted to determine whether to retransmit the packet and how to adjust the stack counter to determine when to retransmit the packet based on the feedback information.

7. The user element of claim 6 wherein the feedback information is one of three messages consisting of a first message indicating a relatively large ratio of successful to unsuccessful channels, an intermediate ratio of successful to unsuccessful channels, and a relatively low ratio of successful to unsuccessful channels.

8. The user element of claim 1 wherein the control circuitry is further adapted to select channels from a plurality of channels to use for transmitting packets to the access point based on a relative length of the packets to be transmitted.

9. The user element of claim 1 wherein the control circuitry is further adapted to select channels from a plurality of channels to use for transmitting packets to the access point based on a frequency in which access is required.

10. The user element of claim 1 wherein the control circuitry is further adapted to select channels from a plurality of channels to use for transmitting packets to the access point based on a volume of data to be transmitted.

11. The user element of claim 1 wherein the control circuitry is further adapted to redundantly transmit the packet over multiple channels to increase a relative priority of the user element.

12. The user element of claim 1 wherein the control circuitry is further adapted to redundantly transmit the packet during multiple time slots to increase a relative priority of the user element.

13. The user element of claim 1 wherein the control circuitry is further adapted to redundantly transmit the packet over multiple channels and during multiple time slots to increase a relative priority of the user element.

15. The access point of claim 6 wherein the feedback message is one of three messages selected from the group consisting of a first message indicating a relatively large ratio of successful to unsuccessful channels, an intermediate ratio of successful to unsuccessful channels, and a relatively low ratio of successful to unsuccessful channels.

14. An access point for facilitating random access communications comprising:

a) receive circuitry;

b) transmit circuitry; and

c) control circuitry associated with the receive and transmit circuitry and adapted to;

i) receive packets transmitted via at least one of a plurality of channels from a plurality of user elements during a time slot;

ii) determine a number of successful channels in which packets were properly received during the time slot;

iii) determine a number of unsuccessful channels in which packets were not properly received during the time slot; and

iv) transmit a feedback message based on a relative number of successful channels in which packets were properly received to a relative number of unsuccessful channels in which packets were not properly received.

16. A method for facilitating random access communications from a user element comprising:

a) transmitting a packet stored in a buffer to an access point during a time slot when a stack counter is a nominal value; and

b) adjusting the stack counter when feedback information received from the access point is indicative of the packet needing to be retransmitted, the feedback information sent to a plurality of user elements in a communication environment.

17. The method of claim 16 further comprising implementing one of a plurality of random number generators to generate a random number, which determines a relative amount by which the stack counter is adjusted such that different user elements will have different priorities based on the one of the plurality of random number generators implemented.

18. The method of claim 17 wherein the different ones of the plurality of random number generators have a different number of possible outcomes such that a relative priority is decreased as the number of possible outcomes is increased.

19. The method of claim 17 further comprising retransmitting the packet at an increased power level when the feedback information is indicative of the packet needing to be retransmitted.

20. The method of claim 16 further comprising selecting channels from a plurality of channels to use for transmitting packets to the access point on a packet-by-packet basis and transmitting the packets on the selected channels.

21. The method of claim 16 wherein the feedback information is indicative of a relative number of successful channels in which packets were properly received to a relative number of unsuccessful channels in which packets were not properly received, and further comprising determining whether to retransmit the packet and how to adjust the stack counter to determine when to retransmit the packet based on the feedback information.

22. The method of claim 21 wherein the feedback information is one of three messages consisting of a first message indicating a relatively large ratio of successful to unsuccessful channels, an intermediate ratio of successful to unsuccessful channels, and a relatively low ratio of successful to unsuccessful channels.

23. The method of claim 16 further comprising selecting channels from a plurality of channels to use for transmitting packets to the access point based on the relative length of the packets to be transmitted.

24. The method of claim 16 further comprising selecting channels from a plurality of channels to use for transmitting packets to the access point based on a frequency in which access is required.

25. The method of claim 16 further comprising selecting channels from a plurality of channels to use for transmitting packets to the access point based on a volume of data to be transmitted.

26. The method of claim 16 further comprising redundantly transmitting the packet over multiple channels to increase the relative priority of the user element.

27. The method of claim 16 further comprising redundantly transmitting the racket during multiple time slots to increase a relative priority of the user element.

28. The method of claim 16 further comprising redundantly transmitting the packet over multiple channels and during multiple time slots to increase a relative priority of the user element.

29. A method for facilitating random access communications from an access point comprising:

a) receiving packets transmitted via at least one of a plurality of channels from a plurality of user elements during a time slot;

b) determining a number of successful channels in which packets were properly received during the time slot;

c) determining a number of unsuccessful channels in which packets were not properly received during the time slot; and

d) transmitting a feedback message based on a relative number of successful channels in which packets were properly received to a relative number of unsuccessful channels in which packets were not properly received.

30. The method of claim 29 wherein the feedback message is one of three messages selected from the group consisting of a first message indicating a relatively large ratio of successful to unsuccessful channels, an intermediate ratio of successful to unsuccessful channels, and a relatively low ratio of successful to unsuccessful channels.