1. An effective method to actualize smooth and fast handoff

2. Concepts, theories and protocols used in this method
Virtual AP technique
IEEE802.11F protocol

3. Application of Virtual AP
As there could be only one AP considered by wireless network card by using “Virtual AP”, we utilize this technique to reduce the duration in the detection and searching stages in the most degree before touching off the handoff process.

4. Make these factors configure identical in each physical AP
1.Wireless MAC address
2.BSSID
3.SSID

5. The brief introduction of IEEE802.11F protocol

6. The revision and supplement to IEEE802.11F in this method
Modify some functions in hostap source code to actualize the correspondence among primitives in respect to the “add” part in IEEE802.11F
Add some key functions to hostap source code to actualize the correspondence among primitives in respect to the “move” part in IEEE802.11F
Revise and supply some parts of hostap source code to solve the problem of exclusive channel collision

7. To solve the problem of exclusive channel collision

8. When a station is in APs’overlay region, sending the first packet to the channel, it may meet the exclusive channel collision.
We let AP1 and AP2 accept the first packet* at random.
Set time stamps in packet** and packet*** after accepting packet*.
Send packet** from AP1 to AP2 and packet*** from AP2 to AP1 by IEEE802.11F protocol through ether net.
Comparing the time stamps in ** and ***, the shorter one’s source AP can occupy the wireless channel to continue sending and receiving the follow packets.

9. When a station is moving from one AP’s coverage region to another, it may need to touch off handoff process
We use IEEE802.11F protocol to send packets including the information of station’s MAC address, sequence number .etc from old AP to those in the AP neighbor graph.
If the new AP gets the relevant information of sta in advance, it can associate with sta more quickly and effectively.

11. THE END ! THANK YOU!