802.11ac is the latest WiFi standard and uses the 5.8GHz frequency band. Older standards 802.11n and earlier used 2.4GHz as its frequency band.
Advantages of 802.11ac over 802.11n
802.11AC is the latest standard and has six major improvements over 802.11n that result in much higher throughputs:
- Uses 5GHz band, which is much less congested than 2.4GHz: 802.11n runs on the heavily overused 2.4GHz which is prone to interference from the many devices on this spectrum. Although it has less penetrating power, the 5GHz band is free from high noise and congestion. A quality Wi-Fi antenna fitted to a 5GHz router improves its range within usable distances. 2.4 GHz is optional with 802.11ac.
- 80MHz channel: 2x the width of 802.11n: 802.11n can only support a 4X40MHz bandwidth compared to 802.11ac’s 8X160Mhz. the high-density modulation allows 256 different signals to be transmitted over the same frequency by phase shifting each signal; this improves the spectral efficiency up to 4 times over 802.11n.
- 256QAM: This provides a 1/3 increase in throughput
- MU-MIMO: Multi-user MIMO functions like a switch, whereas 802.11n functions like a hub.
- 802.11ac uses 8x8 MIMO vs. 802.11n's maximum of 4x4 MIMO (most 802.11n uses 2x2 MIMO in 2015: That is to say, 802.11ac has 8 special streams, whereas 802.11n has a maximum of 4: 8x8 MIMO is double the throughput of 4x4 MIMO.
- Beamforming: 802.11ac also introduces standardized beamforming transmission technology. Beamforming transmits only the required signal to the specific user. This makes transmission more efficient, consistent and saves on the power cost of transmission.
All of the advantages combined result in 802.11ac having a combined multiple-station throughput of at least 1Gbs and a singular throughput of at least 500Mbs through a single link. 802.11ac features a wider bandwidth of 160MHz, up to 8 MIMO special streams, higher density modulation of 256 QAM, and up to 4 simultaneous downlink users.
You will attain all of these benefits only if all the APs and devices in the network are 802.11ac. Otherwise, you would have the same performance with 802.11ac as with 802.11n.
Despite the significant differences between the two standards, 802.11ac is fully backward compatible with 802.11n. devices that feature a dual frequency receiver can easily switch between the two standards.
The IEEE 802.11ac is a wireless Wi-Fi standard developed within 2008-2013 to provide high-throughput connectivity across the 5GHZ band. The standard is an improvement on the earlier 802.11n wireless standard transmitting via the 2.4GHz frequency band.
Streaming media on a local-area network: 802.11ac is best choice because of the much higher throughput.
802.11n wireless adapters only work optimally when connecting to a 802.11n that's operating in 802.11n mode.
Frequency Ranges of the 802.11 network-types:
- 802.11ac: 5GHz band
- 802.11n: 2.4GHz & 5GHz bands: 802.11n equipment is made for either 2.4GHz or 5.8 frequency band: 5.8 is typically much less cluttered with signal-traffic.
- 802.11a: 5GHz band
- 802.11b and 802.11g: 2.4GHz only: Operate only in the 2.4GHz frequency band. 802.11G is from 2004 and 802.11B was the first WiFi standard: 1990s to 2004.
WiFi frequency advantages and disadvantages.
WiFi is operable at the following frequencies, with more capacity being aggressively sought in other parts of the radio frequency spectrum as the more congested frequencies being prone to interference. This had led to the expansion of WiFi into the sub microwave and microwave frequencies though coverage is decidedly lower.
● 2.4 GHz frequency band is commonly used for WiFi as this is typically unlicensed around the world. 802.11b/g/n specifies the use of this frequency which provides good coverage and penetration. This frequency band does suffer a lot of interference from other wireless products that use it, including microwave ovens, cordless phones, and wireless technologies like Bluetooth and ZigBee.
● 5 GHz WiFi is specified by 802.11a/h/j/n/ac/ax. It has a far greater capacity than its lower frequency counterparts with up to 23 distinct channels, but lower coverage and penetration of walls.
● 5.9 GHz is currently allocated for Intelligent Transport Systems but has been aggressively targeted for WiFi but has faced pushback from the automotive industry who feel that sharing this band may be a transport safety risk.
● 900 MHz known as WiFi HaLo utilizes the 900 MHz ISM band to provide longer range WiFi coverage with lower energy consumption. Its protocol 802.11ah was published in 2017.
● 6 GHz or the Unlicensed National Information Infrastructure (U-NII) frequency band has an allocation of about 500 MHz for use by WiFi according to the WiFi 6 protocol.
● 60 GHz was devised by the Wireless Gigabit Alliance who merged with the WiFi Alliance to publish the standard 802.11ad. Operating at such a high frequency allows high speed and volume data transfer, especially as there are relatively vast amounts of unallocated spectrum around this frequency. However, coverage is drastically reduced compared to lower frequency networks, often limited to the same room. It is intended to be used alongside lower frequencies or be used as a cable replacement for a short distance, high traffic wireless links.
802.11N: Also called Wireless-N
WIRELESS-N (802.11n) is the previous generation of wireless networking technology - prior to 802.11ac. 802.11n enables speeds up to 300Mbps and is backward compatible with 802.11g & 802.11b.
802.11n built upon the previous 802.11G standard by adding two new technologies:
- Frame Aggregation technology: Increases throughput by sending two or more data frames in a single transmission.
- MIMO (click tab MIMO above)
11n products have one of the following: "3 TX + 3 RX" , "2TX + 2RX" and "1TX + 1RX" ~ all of them using MIMO technology. "1TX + 1RX", products only have one antenna.
802.11N is mostly in the 2.4GHz frequency band. 5GHz is an optional component that most manufacturers ignore in favor of the cheaper, and much more congested 2.4GHz.
802.11a uses the frequency range 5.2 to 5.8GHz:
This range of frequencies is much less used than 2.4GHz
802.11a allows for use of so many channels that you don't have to worry about interference between access points. In the U.S., 802.11a offers eight non-overlapping channels vs. three channels shared by 802.11b and 802.11g. If the company or department next door (or upstairs or downstairs) has an 802.11a network, more channels makes it easier to configure your 802.11a network to avoid interference. In dense installations, extra channels can make 802.11a networks up to 14 times faster than 802.11b networks.
If you operate a wireless adapter that's made for wireless-N, on a 802.11B/G network, will have lesser performance/signal strength than a 802.11G adapter of similar standards
We reached these conclusions based in part by comparing the Alfa 1000mw G version and the Alfa 2000mw N version. AWUS036H is the G version; AWUS036NH is the N version.
Connecting to a 802.11G network? Then an 802.11G wireless USB adapter will perform better than an 802.11n USB adapter
802.11b will provide better range/distance than 802.11g
802.11g cards automatically select 802.11b mode for long-distance connection
Posted by George Hardesty on 16th Mar 2019