I had some issues with my upgrade to WordPress V4.0 and I’m a little late in posting this week but I’ve fixed the issues so I can get back to posting. I’ve been focusing on the ‘Plan and Design 802.11 Wireless Technologies’ topic and I thought it would be a good idea to post about the fundamentals of the 802.11b,g,a,n standards over a number of posts. In this part I will briefly go through the history of the IEEE WLAN standard, this will be a short post that will give a little background around the standards in use, specifically for the current CCIE wireless curriculum.
Back in 1991 the IEEE formed a new group to define a WLAN standard, the first of which was completed in 1997 and allowed for a maximum throughput of up to 2Mbps. This standard also specified two RF transmission modulations, namely, Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS). In 1999 802.11b was standardised and allowed for additional throughput of up to 11Mbps within the 2.4Ghz band. At this time, 802.11a was also ratified to allow for a maximum throughput of 54Mbps within the 5Ghz band. The 802.11a standard additional made use of a new transmission modulation technique called Orthogonal Frequency-Division Multiplexing (OFDM) to provide the higher data throughput. In 2003 the 802.11g was standardised to provide a throughput of up to 54Mbps in the 2.4Ghz band and also utilises OFDM as its RF modulation. To meet the increasing demand for throughput a new standard, 802.11n, was ratified 2009 and allowed for a maximum throughput of 900Mbps by exploiting channel-bonding and Multiple-In-Multiple-Out (MIMO) with Spatial Multiplexing practices
We can see in the diagram that stakeholders and users of wireless products wanted and continue to demand more throughput. In addition to this there has been an explosion of device and application diversity which again requires more wireless bandwidth with improve signal efficiency in an ever more crowded wireless spectrum. Throughput and link reliability aren’t the only requirements but I hope you can sense that achieving a seamless transition between wired and wireless technologies requires careful planning and implementation. After all, a user doesn’t care about how a technology works or what limitations there might be, they just want a first class perceived user experience to accomplish their day to day tasks.