1. Proposal for a separate QAP EDCF parameter set
March 2003
Proposal for a separate
QAP EDCF parameter set
Richard van Leeuwen, Agere Systems

2. March 2003
The issue
In a QBSS using EDCF, upstream traffic has an advantage over downstream traffic
Several QSTAs contend for the medium to send upstream traffic
A QAP is a single contender, but needs to service downstream traffic for all QSTA in its QBSS.
This asymmetry is often the reverse of what is desired (Think of ADSL)

3. March 2003
The solution
Allow the QAP to use different (higher priority) EDCF parameter values than the values it advertises to the QSTAs in its QBSS

4. March 2003
The current draft
Clauses and do not explicitly allow/disallow the QAP to use different EDCF parameter values
Annex D (MIB) include objects for 1 AC only
dot11HCCWmin, dot11HCCWmax, dot11AIFS
Related letter ballot #51 comments:
430
1001
1046

5. March 2003
Simulation Scenario

6. Flows 5 Voice nodes 0..15 Data nodes
March 2003
Flows
5 Voice nodes
Each with 1 up- and 1 downstream voice flow
UDP, 298 byte packets, 30 msec (G.711)
Voice nodes started after 1 sec (warm-up)
Data nodes
Each with 1 up- and 1 downstream data flow
UDP using 1500 byte packets every 50 msec
1 data node added every second
Both Voice and Data use 11 Mbps transmit rate
802.11b timing
5% Packet Error Rate

7. EDCF Parameters (11b) Default parameter values for all QSTAs
March 2003
EDCF Parameters (11b)
Default parameter values for all QSTAs
Suggested default values for QAP
Traffic type
CWmin
CWmax
AIFS
Best Effort 31
1023 2
Voice 7 15 1
Traffic type
CWmin
CWmax
AIFS
Best Effort 15
511
Voice 7

8. March 2003

9. March 2003

10. March 2003
Proposal
Add sentence in to explicitly allow a QAP to use a different EDCF parameter set
Include a QAP EDCF table to MIB in Annex D
Suggested MIB object:
dot11QAPEDCFTable
With 4 entries (1 for each AC)
Each entry contains attributes:
CWmin, CWmax, AIFS, TXOPLimit