ropping. These oversights were corrected with There are a number of advances at OSI layers 2 and above authentication and encryption systems built into the that will benefit wireless users, some examples of which second generation systems. Likewise, standards will are touched upon here. Over the past 15 years, de- shortly address the security weaknesses of original IEEE ployment of the Internet protocol (IP) has advanced to 802.11 wireless LANs. where it is now a matter of course to connect from any Another major area of research is in the field of quality computer to almost any other computer around the of service (QoS). Applications (e.g., voice or video) that world, and to do it easily and quickly. This expectation work well over dedicated wired links often experience also holds true for telephone-to-telephone connectivity. difficulties when faced with the variable delays, channel In some respects, mobile telephony is more advanced errors, and throughput inherent in many wireless links. than IP networking in that a user can receive a call to his Wireless QoS features will provide a more consistent or her unique identifier (telephone number, including the platform on which to support these applications. In addition to specific research areas exemplified by those just listed, there are several more general trends that will affect the wireless landscape over the coming Smart Antenna years. Increased throughput Apart from some low-speed niche applications such as telemetry, each wireless technology is continually push- ing for higher data rates. Sophisticated modulation and coding can squeeze more data onto existing channels. Additionally, there is a continuing migration to higher frequencies, where there is more bandwidth and thus the potential for higher throughput. Compare for example the newer 802.11a, which supports 54 Mbps on each of up to 12 simultaneous channels at 5 GHz, with 802.11b which offers 11 Mbps on each of three simultaneous channels at 2.4 GHz (under U.S. regulations). Recent news items report t