November 2009
Why is 802.11n so much better than 802.11g?

There are effectively 7 new elements in 802.11n which makes it faster and more reliable than its’ predecessor 802.11g. While there is no avoiding the technical names, what they do is often logically simple. We will outline 6 improvements below. We will ignore Variable Guard Intervals which does not really have a non-technical definition.

• Spatial multiplexing - Think in terms of making a large delivery. Spatial multiplexing is like sending it in several vans, each carrying part of the load. This would deliver your goods a lot faster that having one van running backwards and forwards.
• Channel bonding - 802.11n can combine 2 channels to form what is effectively a dual-carriageway compared to a single lane road. It can then carry twice as much traffic or in this case, data.
• Frame aggregation - If we carry on with our courier analogy, if we use bigger boxes, we should be able to pack more goods into a single box. This is what aggregating frames does, it simply carried more data while avoiding the increase in overheads
• Space-time block coding - By being able to send and receive multiple copies of information over different routes, then combine them to create the best result, we can remove the need to resend information which doesn’t reach it’s destination.
• Block acknowledgements - Again, using our courier example, 802.11g acknowledges the receipt of every delivery. 802.11n sends confirmation for multiple deliveries in one message, freeing time for data to be transmitted.
• Beamforming - Image you are trying to read a book at night. A standard light bulb will spread light round a room regardless of where you are sitting. Image a light that could focus a beam exactly where you need it, even if you move. By concentrating the light into a beam, you would have a much brighter, more reliable light. Beamforming does this with WiFi.

The Ruckus Wireless product range not only delivers the advantages of 802.11n better than any other product, but even delivers key elements of beamforming under 802.11g for more details see the Beamforming White Paper and for those of you who want to see more technical background, try the 802.11n white paper

If you have any questions regarding Wi-Fi WLAN technology please feel free to contact us on 01270-588228. If your question is of general interest, we may include it in our faqs.