Transcript AP discovery with FILS beacon        by Yunbo Li (Huawei)             11-12/0042r3

Mar 2012
doc.: IEEE 802.11-12/0042r2
AP discovery with FILS beacon
• Date: 2012-3-6
Authors:
Name
Affiliations
Yunbo Li
Huawei Technologies Co.,
Ltd.
Robert Sun
Huawei Technologies
Co., Ltd.
Edward Au
Osama Aboul-Magd
Junghoon Suh
Submission
Huawei Technologies
Co., Ltd.
Huawei Technologies
Co., Ltd.
Huawei Technologies
Co., Ltd.
Address
F1, Huawei Industrial
Base, Bantian Longgang,
Shenzhen 518129, China
Suite 400, 303 Terry Fox
Drive, Kanata, Ontario
K2K 3J1
Suite 400, 303 Terry Fox
Drive, Kanata, Ontario
K2K 3J1
Suite 400, 303 Terry Fox
Drive, Kanata, Ontario
K2K 3J1
Suite 400, 303 Terry Fox
Drive, Kanata, Ontario
K2K 3J1
Slide 1
Phone
+86 15013596057
email
[email protected]
+1 613 2871948
[email protected]
+1 773 782 6875
[email protected]
+1 613 2871405
Osama.AboulMagd@hua
wei.com
+1 613 2871315
[email protected]
m
Yunbo Li et al ,Huawei.
Mar 2012
doc.: IEEE 802.11-12/0042r2
Abstract
• In this presentation, the necessity of passive scanning
during AP discovery is described;
• FILS beacon is introduced to accelerate the AP
discovery.
Submission
Slide 2
Huawei.
Mar 2012
doc.: IEEE 802.11-12/0042r2
Conformance w/ TGai PAR & 5C
Conformance Question
Response
Does the proposal degrade the security offered by Robust Security Network
Association (RSNA) already defined in 802.11?
No
Does the proposal change the MAC SAP interface?
No
Does the proposal require or introduce a change to the 802.1 architecture?
No
Does the proposal introduce a change in the channel access mechanism?
No
Does the proposal introduce a change in the PHY?
No
Which of the following link set-up phases is addressed by the proposal?
(1) AP Discovery (2) Network Discovery (3) Link (re-)establishment /
exchange of security related messages (4) Higher layer aspects, e.g. IP address
assignment
1
Submission
Slide 3
Huawei.
Mar 2012
doc.: IEEE 802.11-12/0042r2
Introduction
Fast Initial link setup is required in TGai
– High link setup time will be less than 100ms, which is hard to
achieve when using current AP discovery techniques.
Two ways to discovery AP:
– Passive scanning:
• indispensable in some scenario;
• usually take long time, and need to accelerate it for FILS
– Active scanning:
• Much quicker, but take much air time and easy to flood the network;
• Some filter or cooperate techniques are proposed for FILS;
We introduce a FILS Beacon to accelerate AP discovery
Submission
Slide 4
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Necessity of passive scanning
• Radar band is overlapped with WiFi 5G band;
– Clause 10.9.4 of REVmb D12.0: A STA does not transmit in a
channel unless the channel has been tested for the presence of
radar transmissions according to regulatory requirements.
• Passive scanning is needed in Radar band;
• Current passive scanning need to be improved to meet
the requirement of FILS;
• FILS beacon may be an effective method.
Submission
Slide 5
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r1
Problems in passive scanning
• Current beacon transmitted period (100ms) is too long
for FILS;
• Increase the transmit frequency of Beacon will occupies
much air time, because Beacon frame contains a large
payload (usually > 100 Bytes);
• Increase the transmit frequency of Beacon will
consume more power of mobile STAs.
Submission
Slide 6
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
FILS Beacon
• Define a very short beacon (FILS beacon) to advertise
AP, transmit it much more frequently;
• FILS beacon only contains several necessary element
for discovery;
• FILS beacon will not replace the traditional Beacon
frame, it will be sent much more frequently between
traditional Beacons;
• Note：FILS beacon does not exclude active scanning;
Submission
Slide 7
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Information in FILS beacon
•
•
•
•
SSID
Network Identifier (optional)
Time to the next beacon
…(other element that will help for FILS)
Submission
Slide 8
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Simulation for FILS Beacon
•
•
•
•
NS-2 platform;
5 APs in the simulation;
5 unassociated STAs and 5 associated STAs for each AP;
Each unassociated STAs need to find the AP with
intended SSID;
• Regular Beacon with a BI of 100ms;
• There are only two elements in FILS Beacon: SSID (18
bytes) andTime to next beacon element (6 bytes);
• The simulation results are obtained from 15 independent
experiments.
Submission
Slide 9
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Simulation for FILS Beacon
Ave AP discovery time
(ms)
Background Traffic = 0 Frames/s/STA
600
500
400
Beacon
FILS Beacon
300
200
100
0
0
1
3
5
NO. of inserted (FILS) Beacon
7
Figure 1 Without background traffic
Submission
Slide 10
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Simulation for FILS Beacon
Ave AP discovery time
(ms)
Background Traffic = 5 Frames/s/STA
600
500
400
Beacon
FILS Beacon
300
200
100
0
0
1
3
5
NO. of inserted (FILS) Beacon
7
Figure 2 Background traffic
Submission
Slide 11
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Simulation for FILS Beacon
Ave AP discovery time
(ms)
Background Traffic = 10 Frames/s/STA
600
500
400
Beacon
FILS Beacon
300
200
100
0
0
1
3
5
NO. of inserted (FILS) Beacon
7
Figure 3 Background traffic
Submission
Slide 12
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Simulation for FILS Beacon
Ave AP discovery time
(ms)
Background Traffic = 20 Frames/s/STA
700
600
500
400
300
200
100
0
Beacon
FILS Beacon
0
1
3
5
NO. of inserted (FILS) Beacon
7
Figure 4 Background traffic
Submission
Slide 13
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
What else after FILS beacon
Pure passive scanning:
• Wait for the next beacon if the waiting time is short;
• switch to other channel to do further scanning if waiting time
is long;
Hybrid scanning:
• Send Probe Request frame with intended SSID, and AP reply
with a broadcast Probe Response frame. (Cooperate info can
be included for further improvement);
Submission
Slide 14
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Conclusion
• FILS Beacon can reduce the AP discovery time;
• It has a optimal number of FILS Beacon within a regular BI
(100ms), it could be around 3;
Propose:
• Design a specific MAC frame to accelerate the passive
scanning of AP discovery for FILS.
Submission
Slide 15
Huawei
Mar 2012
doc.: IEEE 802.11-12/0042r2
Straw poll 1
• Do you agree the passive scanning need to improve for
FILS?
Submission
Slide 16
Huawei.
Mar 2012
doc.: IEEE 802.11-12/0042r2
Straw poll 2
• Do you agree to introduce the FILS beacon in slides 7
and 8 to accelerate AP discovery?
Submission
Slide 17
Huawei.