Most consumer wireless routers available between around 2008 and 2013 supported the IEEE 802.11n wireless standard, which was developed to ultimately increase the speeds available significantly, also extended the range over which the wireless devices could communicate. Additionally, this standard was designed to improve the reliability of wireless signals. IEEE 802.11n provides these enhancements by means of multiple antennas and wider frequency channels. A technology called MIMO (Multiple Input Multiple Output) was used, which employed multiple antennas on the transmitting and receiving devices and solved some of the problems of multipath propagation caused by obstructions in the line of sight, and therefore scattered signals. These signals would be received over different transmission path lengths and can cause fading or a cut-out of the signal altogether. The more antennas used, theoretically the better the reception. Speeds up to 600Mbps can be achieved, but in reality, with 2 antennas 150Mbps is more the norm. This was a significant increase over the speeds of the earlier standards. The IEEE 802.11n standard could be used in either the 2.4Ghz or 5Ghz frequency bands.
IEEE 802.11ac uses a similar technology to the 802.11n standard, but can increase the number of antennas, and therefore spatial streams to 8 as opposed to 4 and uses a wider channel up to 160Mhz wide. Modulation schemes used by the "n" standard ranged from BPSK (Bi Phase Shift Keying) to 64QAM (64 point Quadrature Amplitude Modulation). The improved reliability and reduction of the effects of multipath and therefore improved error rates due to the use of 8 spatial streams allowed for a modulation scheme of 256QAM, therefore raising the potential transmission rates above 1Gbps. The use of smart antennas that are able to beamform and direct the beam at the target device helped to increase the throughput data rates. With the use of wider channels (80Mhz / 160Mhz), 802.11ac is operated in the 5Ghz band because the 2.4Ghz ISM frequency band has less overall bandwidth available. Theoretically, this wireless standard using the maximum 8 x 160Mhz channels, each utilising 256QAM can provide for speeds up to nearly 7Gbps, or a data rate up to around 900 megabytes per second.
It pays to shop around if you are looking at replacing your old 802.11n router with an 802.11ac model, as speeds and performance can vary quite significantly. Even streaming high definition TV is no problem at all over these wireless networks.
Development of 802.11ac continues by vendors, and although 7Gbps is a theoretical speed, in reality speeds of several Gbps will soon be achieved, which will provide for a data throughput that far outstrips that of Fast Ethernet.
This article on Wireless Networks was written by David Christie, Website http://www.nstuk.com