Planning the infrastructure for IEEE 802.11ac

With IEEE 802.11ac, the new standard for wireless local networks, a further increase is to be expected for WiFi applications. This WLAN enables data rates of up to 7 Gigabits per second. This new generation is called Wave2.

WLAN

Are we soon going to reach the point where we no longer require fixed cabling in offices? No! Because even access points are usually connected using structured cabling.

In the case of modern WLAN products (compliant with IEEE 802.11ac), the bandwidth required on the cable side is more than 1 Gbit/s. Access points, therefore, have to be connected with several 1000BASE-T ports. This increases the cabling complexity. The alternative would be a 10GBASE-T connection.

The planned transmission technology NBASE-T, which enables 2.5 or 5 Gbit/s over existing Cat. 5 and Cat. 6 cabling, is a possible interim solution. But this is hardly going to be enough long term. 

Reducing WLAN radio cells

coverage of a single radio cell

Degree of coverage of a single radio cell. For the workplace directly under the access point, the field strength relations are perfect to guarantee a maximum data rate. The many moderately supplied workstations slow down the data throughput.

Capacity-based WLAN planning common today features lots of small radio cells. They are operated with correspondingly low performance to prevent interference with adjacent cells and to ensure a high data rate per subscriber.

The honeycomb radius of 12 meters prescribed in the standard, or rather the resulting distance between access points of 21 meters, has to be viewed as outdated. Today WLAN manufacturers are issuing recommendations for the distance between access points in the workplace of 14 meters (honeycomb radius: 8 meters). With those figures likely to decrease.

Honeycomb structure

Honeycomb structure compliant with EN 50173-6, Amendment B. SO = service outlet. The coverage radius of a radio cell will be considerably less than twelve meters in the future.

Cabling compliant with the honeycomb structure presented in EN 50173-6, Amendment B, is successful in this respect. What is crucial in deciding the future effectiveness of this cabling is choosing the correct honeycomb radius which is relative to the cell size of the WLAN.

Alongside the changes in technology, influencing factors such as the concentration of workstations and changes in use have to be taken into consideration. This is why it is important to plan installations long term.