Method and system for optimally serving stations on wireless LANs using a controlled contention/resource reservation protocol of the IEEE 802.11e standard

• US 20030161340A1
• Filed: 08/29/2002
• Published: 08/28/2003
• Est. Priority Date: 10/31/2001
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sherman, Matthew J.
• Granted Patent: US 7,289,529 B2
• Time in Patent Office: Days
• US Class Current: 370/445
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method for optimally serving Stations (STA) on Wireless Local Area Network (LAN) using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard. The Wireless LAN includes multiple STAs, mobile or Stationary, airlinked to an access point as a Basic Service Set (BSS). A Hybrid Coordinator (HC) is co-located with the access point for allocating the bandwidth for the BSS using a Controlled Contention/Resource Reservation protocol defined in the IEEE Standard 802.11(e). The HC transmits Contention Control (CC) frames and initiates Controlled Contention Intervals (CCI) having a selected number of slotted intervals. HC receives Resource Reservations (RR) detailing bandwidth needs from STA contenders during a specified time interval called the Controlled Contention Interval (CCI.). Several parameters are installed in each CC for contention control purpose. The several parameters are controlled to optimize efficient use of the wireless medium and reduce access delays for RR frames contending for the wireless medium.

Claims

1. A method for optimally serving STAs on Wireless LANs using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard comprising:

(a) transmitting Contention Control (CC) frames and initiating Controlled Contention Intervals (CCI) having a selected number of slotted intervals

(b) receiving Resource Reservations (RR) detailing bandwidth needs from STA contenders during the Controlled Contention Interval (CCI);

(c) installing in each CC frame several parameters including at least the number of Controlled Contention Opportunities (CC_OP) or slotted intervals for contention control purposes including feedback on successful RRs; and

(d) controlling and setting the several parameters to optimize efficient use of the wireless medium and reduce access delays for RR frames contending for the wireless medium.

2. The method of claim 1 further comprising:

(e) including in the parameters an optional Permission Probability (PP).

3. The method of claim 1 further comprising:

(f) including in the parameters a set of flags indicating which Traffic Categories (TC) may compete for the CC_OPs.

4. The method of claim 1 further comprising

(g) estimating the number of STA contenders.

5. The method of claim 2 further comprising;

(h) setting the number of slots or CC_OPS to the number of STA contenders.

6. The method of claim 1 further comprising:

(i) adjusting the parameters to account for overhead CCI.

7. The method of claim 1 further comprising:

(j) concatenating CCIs while setting the number of CC_OPs equal to the number of STA contenders in each CCI.

8. A method for optimally serving STAs on Wireless LANs using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard comprising:

(a) setting a counter Empty_CC to 0;

(b) estimating the number of contenders according to prior results for the CC/RR protocol and known traffic patterns;

(c) conducting a test to determine if the number of contenders is less than 1;

(d) determining Optimum CC_OPs and approximating the overhead as 1 or 2 slots;

(e) performing a test”

CC_OPs<

1 whereby a “

yes”

condition sets CC_OPs to +1 and a “

no”

condition transfers to step (f); and

(f) conducting a test;

Empty_CCI<

Max_Empty_CCI, whereby a “

no”

condition ends the process and a “

yes’

condition returns the process to step (b).

9. The method of claim 8 further comprising:

(g) setting CC_OPs=number of STA contenders+1.

10. The method of claim 8 further comprising:

(h) setting CC_OP=number of # of STA+2.

11. The method of claim 8 further comprising

(g) calculating a Permission Probability where:

if contenders>

max contenders, then Permission Probability=Max Cntndrs/Cntndrs and Cntndrs=Max_Cntndrs;

else a “

no”

condition setting a Permission Probability=1;

else leaving cntndrs as is and

(h) resetting the Empty CCI to 0 and a “

yes”

condition incrementing the Empty_CCI counter.

12. Apparatus for optimally serving STAs on Wireless LANs using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard comprising:

(a) transmitting apparatus which transmits Contention Control (CC) frames initiating Controlled Contention Intervals (CCI) having a selected number of slotted intervals and providing feedback on successfully received Resource Reservations;

(b) receiving apparatus which receives Resource Reservations (RR) detailing bandwidth needs from STA contenders during a specified time interval called the Controlled Contention Interval (CCI);

(c) installing apparatus which installs in each CC frame several parameters for contention control purposes; and

(d) controlling apparatus which controls the several parameters to optimize efficient use of the wireless medium and reduce access delays and maintain bandwidth efficiency for RR frames contending for the wireless medium.

13. The apparatus of claim 12 further comprising:

(e) selecting apparatus which includes in the parameters a number of slots or Controlled Contention Opportunities (CC_OP), a Permission Probability (PP) and a set of flags indicating which Traffic Categories (TC) may compete for the CC_OPs.

14. A system for optimally serving STAs on Wireless LANs using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard comprising:

(a) a plurality of stations air-linked to an access point as a basic service set for communication purposes;

(b) a hybrid coordinator coupled to the access point for performing access management bandwidth management including the allocation of station transmission opportunities and the initiation of controlled contention intervals among the stations;

(c) transmitting apparatus which transmits Contention Control (CC) frames initiating Controlled Contention Intervals (CCI) having a selected number of slotted intervals and providing feedback on successfully received Resource Reservations; and

(d) receiving apparatus which receives Resource Reservations (RR) detailing bandwidth needs from STA contenders during a specified time interval called the Controlled Contention Interval (CCI) for optimally serving the stations using a Controlled Contention/Resource Reservation protocol.

15. The system of claim 14 further comprising:

e) selecting apparatus which includes in the parameters a number of slots or Controlled Contention Opportunities (CC_OP), a Permission Probability (PP) and a set of flags indicating which Traffic Categories (TC) may compete for the CC_OPs.