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

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.

1. A method for optimally serving stations on Wireless local area networks 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 Contention Control/Resource Reservation protocol and observed traffic patterns; 
 (c) conducting a test to determine if the number of contenders is less than 1; 
 (d) determining Optimum Controlled Contention Opportunities (CC_OPs) and approximating a number of slots required to report results to a station as 1 or 2 slots; 
 (e) performing a test CC_OPs>1, wherein 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, wherein Empty_CCI is a number of empty Controlled Contention Intervals (CCIs), wherein Max_Empty_CCI is a selected number of Empty_CCIs, and wherein a “yes' condition transfers to step (b). 
 
     
     
       2. The method of  claim 1  further comprising:
 (g) setting CC_OPs=number of station contenders+1. 
 
     
     
       3. The method of  claim 1  further comprising:
 (g) setting CC_OP=number of station contenders+2. 
 
     
     
       4. The method of  claim 1  flitter 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. 
 
     
     
       5. A method for serving stations on Wireless LANs using a Controlled Contention/Resource Reservation protocol of the IEEE 802.11e standard comprising:
 (a) transmitting a Contention Control (CC) frame that specifies a time period for at least one Controlled Contention Interval (CCI) during which station contenders can transmit Resource Reservations (RRs) detailing their bandwidth needs, the at least one Controlled Contention Interval (CCI) having a selected number of Controlled Contention Opportunities (CC — OPs) or slotted intervals; and   (b) receiving Resource Reservations (RRs) from one or more of the station contenders during respective ones of the Controlled Contention Opportunities (CC — OPs) or slotted intervals;   (c) wherein the number of the Controlled Contention Opportunities (CC — OPs) or slotted intervals within the at least one Controlled Contention Interval (CCI) is equal to one of a) an estimate of the number of station contenders, b) an estimate of the number of station contenders+1, or c) an estimate of the number of station contenders+2.   
     
     
       6. The method of claim 5 wherein the Contention Control (CC) frame further specifies a Permission Probability (PP). 
     
     
       7. The method of claim 5 wherein the Contention Control (CC) frame includes a set of flags indicating Traffic Categories (TC) that may compete for the Controlled Contention Opportunities (CC — Ops). 
     
     
       8. The method of claim 5 wherein said at least one Controlled Contention Interval (CCI) comprises two or more concatenated Controlled Contention Intervals (CCIs) each having the same number of Controlled Contention Opportunities (CC — OPs) or slotted intervals. 
     
     
       9. Apparatus for serving stations 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 each initiating at least one specified time interval called a Controlled Contention Interval (CCI);   (b) receiving apparatus which receives Resource Reservations (RRs) detailing bandwidth needs from station contenders during the Controlled Contention Interval (CCI); and   (c) installing apparatus which installs in each CC frame several parameters for contention control purposes, one of said parameters specifying a number of Controlled Contention Opportunities (CC — OPs) or slotted intervals that are included within the Controlled Contention Interval (CCI), the Resource Reservations (RRs) being transmitted within respective ones of the Controlled Contention Opportunities (CC — OPs) or slotted intervals;   (d) wherein the number of Controlled Contention Opportunities (CC — OPs) or slotted intervals of a Controlled Contention Interval (CCI) is equal to one of a) an estimate of the number of station contenders, b) an estimate of the number of station contenders+1, or c) an estimate of the number of station contenders+2.   
     
     
       10. The apparatus of claim 9 wherein at least one of the Contention Control (CC) frames initiates two or more concatenated Controlled Contention Intervals (CCIs) each having the same number of Controlled Contention Opportunities (CC — OPs) or slotted intervals.