142 Software Networks
communications: one 3×3 MIMO communication, one 2×2 MIMO
communication, and a one-way communication.
The peak data rate reaches 250 Mbps per virtual antenna. With four
physical antennas, each bearing three virtual antennas, we obtain
twelve virtual antennas. Thus, the total data rate is 3 Gbps. Also, if the
bands used are wider – say, 80 MHz instead of 20 MHz – then
theoretically we can achieve over 10 Gbps. In actual fact, as for all
Wi-Fi access points, the peak data rate is only achieved in exceptional
cases, where there is no external interference and the clients are
located very near to the antenna. In reality, the nominal data rates are
often divided by at least a factor of 2, but often much more, to obtain
the real data rates.
The group IEEE 802.11ac, with 433 Mbps per antenna over an 80
MHz band and a MIMO with two antennas per client, delivers 866
Mbps per connection with a terminal. With four physical antennas, we
achieve over 3 Gbps. With a bandwidth of 160 MHz, the data rate is
doubled. The standard specifies that there may be up to eight spatial
sectors, which again doubles the data rate. Evidently, these reported
figures are peak data rates, which are only very rarely achieved in
reality. As is the case with all Wi-Fi solutions, fallback rates become
necessary when the conditions are not ideal. Compatibility with
existing standards also requires the adaptation of data rates to conform
to standards which are not compatible with IEEE 802.11ac.
The aim with the new IEEE 802.11ax standard is to further
increase the data rate by using more numerous and more directional
antennas.
6.4. IEEE 802.11ad
The IEEE 802.ad standard is completely new, with frequencies in
the range of 60 GHz. This standard is championed by a group of
manufacturers: the WGA (Wireless Gigabit Alliance). The name of
the product, which is likely to become standard in personal area
networks, is WiGig. However, the basic product could be tri-band
WiGig, operating simultaneously on the 2.4 GHz, 5 GHz and 60 GHz
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communications: one 3×3 MIMO communication, one 2×2 MIMO
communication, and a one-way communication.
The peak data rate reaches 250 Mbps per virtual antenna. With four
physical antennas, each bearing three virtual antennas, we obtain
twelve virtual antennas. Thus, the total data rate is 3 Gbps. Also, if the
bands used are wider – say, 80 MHz instead of 20 MHz – then
theoretically we can achieve over 10 Gbps. In actual fact, as for all
Wi-Fi access points, the peak data rate is only achieved in exceptional
cases, where there is no external interference and the clients are
located very near to the antenna. In reality, the nominal data rates are
often divided by at least a factor of 2, but often much more, to obtain
the real data rates.
The group IEEE 802.11ac, with 433 Mbps per antenna over an 80
MHz band and a MIMO with two antennas per client, delivers 866
Mbps per connection with a terminal. With four physical antennas, we
achieve over 3 Gbps. With a bandwidth of 160 MHz, the data rate is
doubled. The standard specifies that there may be up to eight spatial
sectors, which again doubles the data rate. Evidently, these reported
figures are peak data rates, which are only very rarely achieved in
reality. As is the case with all Wi-Fi solutions, fallback rates become
necessary when the conditions are not ideal. Compatibility with
existing standards also requires the adaptation of data rates to conform
to standards which are not compatible with IEEE 802.11ac.
The aim with the new IEEE 802.11ax standard is to further
increase the data rate by using more numerous and more directional
antennas.
6.4. IEEE 802.11ad
The IEEE 802.ad standard is completely new, with frequencies in
the range of 60 GHz. This standard is championed by a group of
manufacturers: the WGA (Wireless Gigabit Alliance). The name of
the product, which is likely to become standard in personal area
networks, is WiGig. However, the basic product could be tri-band
WiGig, operating simultaneously on the 2.4 GHz, 5 GHz and 60 GHz
www.it-ebooks.info