User Manual

Appendix
BreezeNET PRO.11 Series 9-40 User’s Guide
9.5.12. Point Coordination Function (PCF)
Beyond the basic Distributed Coordination Function, there is an optional
Point Coordination Function, which may be used to implement time-
bounded services, like voice or video transmission. This Point Coordination
Function makes use of the higher priority that the Access Point may gain by
the use of a smaller Inter Frame Space (PIFS).
By using this higher priority access, the Access Point issues polling requests
to the stations for data transmission, hence controlling medium access. To
still enable regular stations to access the medium, there is a provision that
the Access Point must leave enough time for Distributed Access in between
the PCF.
9.5.13. Ad-hoc Networks
In certain circumstances, the users may wish to build up wireless LAN
networks without an infrastructure (more specifically without an Access
Point). This may include file transfer between two notebook users,
co-workers meeting outside the office, etc.
The 802.11 Standard addresses this need by the definition of an “ad-hoc”
mode of operation. In this case, there is no Access Point and part of its
functionality is performed by the end-user stations (such as Beacon
Generation, synchronization, etc.). Other AP functions are not supported
(such as frame-relaying between two stations not in range, or Power
Saving).