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( backbone
BSS extended service set
( ESS ) ESS Roaming BSS
access points ESSID channel
Roaming
IEEE 802.11

2-2Infrastructure
STAAd-Hoc
2.2.2 IEEE 802.11
: (station
:
11
( re-association)

scanning)
2-5
2-5
2-7:
Cell Search Threshold SNR



2.3

16

[11][12][13]
[7] SyncScan
beacon 2-9 beacon
beacon
19ms beacon
beacon[9] selective scanning cachingselective
scanning mask mask 1611
mask (caching : STA
cache)Cache
handoff cache [10]
L2 handover time (periodic scanning & adjacent APs)
(standard 802.11 handover & selective scanning caching)
periodic scanning
probe mode signal strength
-75dBm
17

Handover
Y
[13]
( probe)
request loss detection retransmission probe response
scaning channel
2.

open system
[14][15][16][17][14]
Mishra (neighbor graph)
2-11
A E

C B
de-association messages
de-association message



802.11 IAPP neighbor graph

20
3.

[18][19][20][21][22][18]
transceivers
transceiver
21
( AP1 AP2) 2-14 [19]
multihoming MN 2-15 WLAN interfaces
IF1IF2
IF1 IF2
handoff [20] scan
channel phase subphase subphase

2-16

beacon
NIC NIC
beacon shared beacon channel [22] QoS

QoS QoS

22
2.3