There is an
increasing demand for higher data rates partly becasue of the development of
more powerful multimedia applications and the convergence of voice. data and
video. This need was addressed in IEEE 802.11a supplement for a data rate of 54
Mbps. Due to the crowded nature of the ISM band 802.11a would operate in the
5GHz UNII band. As an intermediate step IEEE 802.11g specifies data rates of 20+
Mbps. There was some competition on the modulation/coding technique to be used
between Texas Instrument's (TI) Packet Binary Convolutional Code (PBCC) and
Intersil's proposed Orthogonal Frequency Division Multiplexing (OFDM) scheme. In
May, 2001 Intersil won the battle but it has taken some time for the IEEE to
ratify the standard. It should be noted that the standard is to work at 2.4 GHz
with a (hopefully) seamless migration to 802.11a.
HiperLAN is a broadband wireless ethernet standard
developed by the European Telecommunications Standards Institute (ETSI) and
similar to the 802.11 standards. HiperLAN/2 provides data rates up to 54 Mbps in
the 5 GHz UNII band (which is the same specification in 802.11a).
Issues such as backward compatibility of 802.11a and 802.11g with 802.11b have to be resolved in order to ensure the economic viablity of wireless ethernet networks.