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This document proposes a solution to reduce needless packet exchanges and improve AP discovery in TGai by modifying the use of Probe Requests and Responses. The goal is to enhance WLAN air circumstances and optimize the FILS advantages effectively.
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Katsuo Yunoki, KDDI R&D Laboratories Probe Request and Response in TGai Authors: • Date: 2011-10-27
Katsuo Yunoki, KDDI R&D Laboratories Abstract • This document describes a technical proposal for TGai which addresses the following phase. • AP Discovery
Katsuo Yunoki, KDDI R&D Laboratories Conformance w/ TGai PAR & 5C
Katsuo Yunoki, KDDI R&D Laboratories Background • Time occupied situation in the real case was presented in Doc. 寄与文書案(1)r. • The time occupied rate will become higher and higher because of Smartphone increasing. • Thus, we have to consider reducing needless packet exchanges which occur packet collisions and bigger latency in order to obtain the FILS advantages effectively.
Katsuo Yunoki, KDDI R&D Laboratories Probe Request/ Response • In order to search the surrounding APs, a STA receives Beacon and transmit Probe Request in Broadcast. • APs transmit Probe Response for responding received Probe Requests in unicast. STA AP1 AP2 AP3 AP4 Probe Request (wildcard) Probe Response
Katsuo Yunoki, KDDI R&D Laboratories Example of Probe Request • This STA transmits multiple “Probe Request” about every 15 seconds. • 5 Probe Requests were observed around time stamp of 104 seconds. * Source MAC address was modified.
Katsuo Yunoki, KDDI R&D Laboratories Example of Probe Response • 3 SSID were responded for probe requests. • 26 probe responses were observed for 5 probe requests in Slide 7.
Katsuo Yunoki, KDDI R&D Laboratories Considerations • “Probe Request / Response” cause packet flooding even if the STA doesn’t have any connecting capabilities to surrounding APs. • Transmitting “Probe Request” every 15 seconds doesn’t help the fast AP discovery. • Avoiding needless packets may bring clearer WLAN air circumstances.
Katsuo Yunoki, KDDI R&D Laboratories Proposal • I’d like to propose that: • STA complied with TGai shall not use the wildcard SSID in SSID element of “Probe Request”. • AP complied with TGai shall not transmit “Probe Response” for “Probe Request” with the wildcard SSID. • I’d like to invite comments from experts.
Katsuo Yunoki, KDDI R&D Laboratories References • doc.: IEEE 11-11/1413r0