In ETSI the standards are defined by the BRAN project (Broadband Radio Access Networks).
CAC layer provides hierarchical independence with Elimination-Yield Non-Preemptive Multiple Access mechanism (EY-NPMA).
EY-NPMA codes priority choices and other functions into one variable length radio pulse preceding the packet data.
EY-NPMA enables the network to function with few collisions even though there would be a large number of users.
An innovative feature of HIPERLAN 1, which other wireless networks do not offer, is its ability to forward data packets using several relays.
[1] The physical layer of HiperLAN/2 is very similar to IEEE 802.11a wireless local area networks.
[1] The standard covers Physical, Data Link Control and Convergence layers.
Convergence sublayers can be used also on the physical layer to connect IP, ATM or UMTS networks.
Most important worldwide manufacturers of HiperLAN/2 are Alvarion (Israel), Freescale (USA), Panasonic (Japan).