Method and apparatus for a self-correcting bandwidth request/grant protocol in a wireless communication system

• US 20040213197A1
• Filed: 05/17/2004
• Published: 10/28/2004
• Est. Priority Date: 05/21/1999
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bourlas, Yair, Stanwood, Kenneth L., Spinar, Brian, Serok, Amir, Zimmerman, Ofer
• Granted Patent: US 7,548,534 B2
• Time in Patent Office: Days
• US Class Current: 370/346
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/561 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0092 Indication of how the channel is divided
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections
• CPC Class Codes: H04W 28/0268 using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] negotiating SLA or negotiating QoS H04W28/24
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 76/11 : Allocation or use of connection identifiers
• CPC Class Codes: H04W 8/24 : Transfer of terminal data

Abstract

A method and apparatus for a self-correcting bandwidth request/grant protocol in a broadband wireless communication system is disclosed. The self-correcting bandwidth request/grant protocol utilizes a combination of incremental and aggregate bandwidth requests. In accordance with the present inventive protocol, CPEs primarily transmit incremental bandwidth requests to their associated base stations, followed by periodic transmissions of aggregate bandwidth requests. The use of incremental bandwidth requests reduces risks that a base station erroneously issues duplicate bandwidth allocations to the same CPE for the same connection. Race conditions that may have occurred using only aggregate bandwidth requests are eliminated by requiring the CPEs to request bandwidth in an incremental manner. However, use of periodic aggregate bandwidth requests (that express the current state of their respective connection queues) allows the present bandwidth allocation method and apparatus to be “self-correcting.” The present method is self-correcting because errors that may have been introduced due to lost incremental bandwidth requests are corrected by the base stations when the aggregate bandwidth requests are received and processed. Upon receipt of the aggregate bandwidth requests, the base stations reset their records to correctly reflect the current bandwidth requirements of their associated CPEs. Periodic use of aggregate bandwidth requests provides a self-correcting bandwidth allocation protocol yet without the bandwidth overhead (e.g., bandwidth required to transmit acknowledgements) typically associated with the prior art protocols (such as the guaranteed delivery protocols).

Claims

1. A method of bandwidth allocation in a system in which multiple remote units share access to a common base station, the method comprising:

receiving a data-bearing packet from a first remote unit, the data-bearing packet including a bandwidth request header in which a poll-me bit is set; and

sending an indication of an increase in a general uplink bandwidth allotment to the first remote unit which can be used by the first remote unit for either data transfer or bandwidth request purposes as determined by the remote unit.

2. The method of claim 1 further comprising the step of using the increase in the general uplink bandwidth by the first remote unit to send data-bearing traffic to the base station.

3. The method of claim 1 wherein the increase in the general uplink bandwidth allotment is sufficient to allow the first remote unit to respond with a bandwidth request message.

4. The method of claim 1 wherein the indication includes no express acknowledgement of receipt of the data-bearing packet.

5. The method of claim 4 further comprising the step of receiving a responsive bandwidth request message from the first remote unit, the responsive bandwidth request message indicating an incremental need for additional uplink bandwidth resources.

6. The method of claim 5 wherein the responsive bandwidth request message specifies an individual connection of a set of connections serviced by the remote unit further comprising incrementing a queue length storage indictor corresponding to the individual connection in response receiving the responsive bandwidth request message.

7. The method of claim 6 further comprising using a bandwidth allocation algorithm to determine whether to grant the additional bandwidth in response to the responsive bandwidth request message.

8. The method of claim 7 further comprising sending a second indication of a second general bandwidth grant to the remote unit without specifying the individual connection and which can be used by the remote unit to communicate data from any one of the set of connections as determined by the remote unit.

9. The method of claim 1 further comprising receiving a bandwidth request message from the first remote unit, the bandwidth request message indicating an incremental need for additional uplink bandwidth resources for an individual connection of a set of connections serviced by the remote unit.

10. The method of claim 9 further comprising updating a queue length storage indictor corresponding to the individual connection in response receiving the bandwidth request message.

11. The method of claim 7 further comprising sending a second indication of a general bandwidth grant to the remote unit which can be used by the remote unit to communicate data from any one of the set of connections as determined by the remote unit.

12. A bandwidth allocation system in which multiple remote units share access to a common base station, the system comprising:

means for receiving a data-bearing packet from a first remote unit, the data-bearing packet including a bandwidth request header in which a poll-me bit is set; and

means for sending an indication of an increase in a general uplink bandwidth allotment to the first remote unit which can be used by the first remote unit for either data transfer or bandwidth request purposes as determined by the remote unit.

13. The system of claim 12 further comprising means within the first remote unit for using the increase in the general uplink bandwidth to send data-bearing traffic.

14. The system of claim 12 wherein the increase in the general uplink bandwidth allotment is sufficient to allow the first remote unit to respond with a bandwidth request message.

15. The system of claim 12 wherein the indication includes no express acknowledgement of receipt of the data-bearing packet.

16. The system of claim 15 further comprising means for receiving a responsive bandwidth request message from the first remote unit, the responsive bandwidth request message indicating an incremental need for additional uplink bandwidth resources.

17. The system of claim 16 wherein the responsive bandwidth request message specifies an individual connection of a set of connections serviced by the remote unit further comprising means for incrementing a queue length storage indictor corresponding to the individual connection in response receiving the responsive bandwidth request message.

18. The system of claim 17 further comprising a bandwidth allocation algorithm which determines whether to grant the additional bandwidth in response to the responsive bandwidth request message.

19. The system of claim 18 further comprising means for sending a second indication of a second general bandwidth grant to the remote unit without specifying the individual connection and which can be used by the remote unit to communicate data from any one of the set of connections as determined by the remote unit.

20. The system of claim 12 further comprising means for receiving a bandwidth request message from the first remote unit, the bandwidth request message indicating an incremental need for additional uplink bandwidth resources for an individual connection of a set of connections serviced by the remote unit.

21. The system of claim 20 further comprising means for updating a queue length storage indictor corresponding to the individual connection in response receiving the bandwidth request message.

22. The system of claim 18 further comprising means for sending a second indication of a general bandwidth grant to the remote unit which can be used by the remote unit to communicate data from any one of the set of connections as determined by the remote unit.

23. A base station for use in a communication system where one or more remote units compete for limited uplink resources, the base station comprising:

a low level media access arbiter (LL-MAA) controlling communication over a first physical channel between a first remote unit and the base station; and

a high level media access arbiter (HL-MAA) controlling communication over a plurality of physical channels including the first physical channel, the HL-MAA logically coupled to the LL-MAA;

wherein the LL-MAA sends a general bandwidth grant of uplink resources over the first physical channel which can be used by the first remote unit to transmit data-bearing traffic to the LL-MAA and wherein the LL-MAA receives in response thereto an explicit bandwidth request message.

24. The base station of claim 23 wherein the LL-MAA comprises a logical state of an uplink data queue corresponding to the first remote unit and wherein the LL-MAA uses the logical state to send an indication of physical channel congestion to the HL-MAA.

25. The base station of claim 23 wherein the LL-MAA comprises a logical state of an uplink data queue corresponding to the first remote unit and wherein the LL-MAA updates the logic state based upon incremental and aggregate bandwidth requests received from the first remote unit.

26. The base station of claim 25 wherein, in response to an incremental bandwidth request, the LL-MAA updates the logical state based on a current value of the logical state and wherein, in response to an aggregate bandwidth request, the LL-MAA replaces the current value of the logical state with a value indicated by the aggregate bandwidth request.

27. The base station of claim 23 wherein the LL-MAA comprises a logical state of an uplink data queue corresponding to the first remote unit and wherein the logical state comprises queue length information storage for a plurality of different quality of service (QoS) levels of a set of connections serviced by the first remote unit.

28. The base station of claim 27 wherein the LL-MAA further comprises a fairness module for allocation of uplink resources on the first physical channel corresponding to the plurality of different QoS levels of the set of connections serviced by the first remote unit.

29. The base station of claim 27 wherein when the LL-MAA receives a bandwidth request message from the first remote unit, the LL-MAA updates a current value of the queue length of information storage corresponding to a QoS demanded by a individual connection specified by the first remote unit in the bandwidth request message.

30. A method of uplink resource allocation performed by a base station in a system in which multiple remote units compete for limited uplink resources, comprising:

determining whether a “

poll-me”

bit has been sent by a first remote unit; and

if the “

poll-me”

bit is set, creating an uplink map which allocates additional uplink bandwidth to the first remote unit, wherein the additional bandwidth can be used by the first remote unit to send data or to send a bandwidth request as determined by the first remote unit.

31. The method of claim 30 further comprising:

determining whether a predetermined time has elapsed since a second remote unit has been polled; and

if the predetermined time has expired, amending the uplink map to allocate additional uplink bandwidth to the second remote unit, wherein the additional bandwidth can be used by the second remote unit to send data or to send a bandwidth request as determined by the second remote unit.

32. The method of claim 30 further comprising monitoring an uplink channel for a bandwidth request message from the first remote unit and wherein no explicit acknowledgement of the allocation is received.

33. A method of uplink resource allocation performed by a base station in a system in which multiple remote units compete for limited uplink resources, comprising:

determining if additional uplink bandwidth is available for use by individual remote units to request uplink resources;

scheduling an uplink resource for a first remote unit and transmitting an uplink map allocating sufficient bandwidth to the first remote unit to respond with a standard bandwidth request message; and

awaiting a responsive message from the first remote unit within the uplink resources wherein the responsive message is determined by the first remote unit and can comprise one of connection data, a bandwidth request for a specified connection or stuff bytes if no additional resources are needed.