1. Frequent Handover Authors: Date:2006-01-04 Jan 2006 Month Year
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Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

2. Month Year
Jan 2006
Jan 2006
Abstract
This document suggests the solution for frequent handover of STA in ESS for Wireless Network Management.
Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

3. Agenda Possible FH Avoid Condition Frequent handover avoid illustrator
Month Year
Jan 2006
Jan 2006
Agenda
Possible FH Avoid Condition
Frequent handover avoid illustrator
Frequent Handover process
Frequent handover frame format
Possible approach for frequent handover detection
Proposed text
Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

4. Introduction What should we solve about this problem:
Month Year
Jan 2006
Jan 2006
Introduction
What should we solve about this problem:
When and how to diminish the “ping pang effect”;
No or less infection on the normal roaming behaviour of STA;
It is necessary to collect all the factors about handover and evaluate these factors when handover happens. HoOP will be helpful for both the network side and the client side.
Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

5. Possible FH Avoid Condition
Jan 2006
Possible FH Avoid Condition
Time varying wireless channel environment
radio circumstance
client's movement
Requirement of load balancing
user number or traffic
traffic’s level, QoS
Transmit power adjustment or advanced power control
Support dynamic channel select
And so on
Bin Wang, ZTE Corporation

6. Frequent handover avoid illustrator
Jan 2006
Frequent handover avoid illustrator
Bin Wang, ZTE Corporation

7. Frequent Handover Process
Jan 2006
Frequent Handover Process
In a distributed infrastructure network, FHAAP should monitor and supervise every STA’s handover behavior.
When the STA init a handover request (whether fast transition or not), some measurement report will be transmit to the FHAAP. The AP could init a k measurement report process or the measurement report be transmitted within the HO request frame.
FHAAP memorize the measurement report and perform the frequent handover detection.
If FHAAP can confirm the STA has been in frequent handover status, FHAAP will enable or update the FHAP (frequent handover avoid policy) of the STA and the other FHAAP in the same ESS, so as to avoid the STA’s frequent handover.
Bin Wang, ZTE Corporation

8. Frequent Handover process (optional)
Jan 2006
Frequent Handover process (optional)
In the FH status, the STA who want to handover will request a FH request to the FHAAP it connected, and the FHAAP will control the request according to the FHAP.
Bin Wang, ZTE Corporation

9. Frequent handover frame format
Jan 2006
Frequent handover frame format
HO request frame format
Bin Wang, ZTE Corporation

10. Frequent handover frame format
Jan 2006
Frequent handover frame format
HO response frame format
Bin Wang, ZTE Corporation

11. Frequent handover frame format
Jan 2006
Frequent handover frame format
FHAU frame format
Bin Wang, ZTE Corporation

12. Frequent handover measurement report
Month Year
Jan 2006
Jan 2006
Frequent handover measurement report
The measurement report that a STA pass to the ESS should contain:
1) average RSSI list of candidate APs;
2) neighbor report (11k);
3) handover threshold status;
4) transmit power;
5) channel quality;
6) the load level of candidate APs;
Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

13. Frequent handover avoid policy
Jan 2006
Frequent handover avoid policy
The FHAP will contain following parameter:
1) adaptive handover threshold value;
2) frequent handover status;
3) transmit power control;
4) dynamic channel control;
5) load scheme control;
Bin Wang, ZTE Corporation

14. Possible approach for frequent handover detection
Month Year
Jan 2006
Jan 2006
Possible approach for frequent handover detection
Distinguish different kind of handover ;
Gather STA’s information during handover;
Evaluate the history of signal strength;
Evaluate the transmit power;
Evaluate the load information;
Evaluate the channel quality;
Evaluate the location information;
Evaluate the handover window status;
Judgments will depend on:
The target of handover
The handover times during a period of time
Bin Wang, ZTE Corporation
Bin Wang, ZTE Corporation

15. Jan 2006
Proposed text
TGv should consider to solve the problem of frequent handover in wireless network management, supply detect/avoid/control mechanism.
TGv should take the following factors into account when solve frequent handover:
Signal strength
Single direction channel caused by AP’s different emission power from different vendors or different model.
Network resources or load information
To include Frequent Handover Control as requirement item to TGv work list
To include Frequent Handover Control as additional item in the TGv Objectives document
Bin Wang, ZTE Corporation

16. Poll for TGv Objectives
Jan 2006
Poll for TGv Objectives
Should TGv take frequent handover as a new requirement ?
Yes:
No:
Abstain:
Bin Wang, ZTE Corporation

17. Jan 2006
Feedback?
Bin Wang, ZTE Corporation