802.11n Protocol

The first original protocol in this, 802.11 series to be introduced was the 802.11 protocol, since then technology has progressed more rapidly than the standards, hence, to meet up with the rising demand for faster and more efficient networks, extension to the original protocol were made to fulfill the requirement. All the 802.11 protocols are compatible with one another, except the 802.11a and 802.11n protocol, as their underlying architecture is different than the other protocols present in this family.

The 802.11n protocol is the latest protocol to be produced in this family; therefore it is still present in the draft version in the market. It has not been yet ratified, that is, it is still under construction. Still it has been mostly developed and used by the vendors, but the registered and totally complete version is still awaited. The thing that makes this protocol quite special is that in a pure 802.11n environment, this protocol is capable of giving speeds up to 300 Mbps, however, some of the documentation says that it will only be capable of providing 100 Mbps at the maximum, the reason for this statement is that, there will be other 802.11 protocol clients present as well and moreover, this protocol will be backward compatible with 802.11b/g and a protocol.

The speed capability and backward compatibility comes from the use of multiple antennas and a technology called multiple inputs, multiple output or MIMO. This technology makes use of different antenna to send and receive the information, thus the speed of the data transfer. This technology comes in three different types. Firstly, Precoding. Secondly, Spatial Multiplexing and thirdly, diversity coding.
Precoding is a function that takes the advantage of the different antennas and multipath issues. In precoding the spatial multiplexing receives a signal and splits it into several lower rate streams, and then sends each one out of different antennas.