The mobile client initiated handover mechanisms for 802.11 being
currently deployed lead to unacceptable long interruptions of the
link layer connection due to the required scanning phase. If the
quality of an established connection falls below a certain threshold,
the mobile client has to break the connection and use its transceiver
for the detection of a more suited access point.
Beside the long interruption of the connection, several other drawbacks
emerge. For instance, a client may associate with an access point
and leave its coverage area shortly after the establishment of the
new connection because the location of the access point is in the
opposite direction of the client's movement.
One possibility to overcome this drawback is to introduce the locations
of the access points to the mobile clients. This can be achieved
by some enhancements of 802.11 amendments being currently in the
standardization process. By possessing the positions of the access
points, a client can make handover decisions dependent on its current
movement in order to avoid long scanning phases, short time connections
and frequent handovers.