Implementing 802.11ac – revolution or evolution?: Page 3 of 4

April 14, 2014 //By Stephane Persyn, Fluke Networks
The 802.11ac standard is due to be ratified in early 2014. This article explains what it offers and provides tips on planning implementation.
performance and require fewer APs, but technologies such as beamforming mean signal strength is not a true indicator of WLAN performance. Engineers will need to measure throughput, carrying out active site surveys as well as lperf surveys so they can measure and map actual end-user performance using an 802.11ac adapter.

2) Capacity – to find out if there is sufficient WLAN capacity in a hybrid network requires a network performance planning tool that supports both existing and new protocols. Measuring channel width, channel overlap and MCS coverage will help assess where high throughput can be obtained to support high client density.

3) Channel allocation – the wider channels introduced with 802.11ac make co-channel interference more likely, so it is important to develop a channel application plan. 802.11ac designates one sub-channel in a bonded channel as ‘primary’; this is used for transmission at a specific bandwidth. The planning tool needs to show where primary and secondary channels interfere with each other to enable adjustment of channel allocations and AP locations to maximise performance.

4) Impact of using DFS channels – to avoid using the same frequency range as radar, the 5 GHz band contains channels with Dynamic Frequency Selection (DFS) capabilities, and the AP has to vacate its channel if it detects radar. A planning tool incorporating a spectrum analyser will identify if DFS channels are available or occupied and show any non-WiFi interference.

5) Impact of older standards – in a hybrid network it is vital to ensure that the slower transmission rates of older standards do not reduce 802.11ac performance. A coverage map enables visualisation of the areas where legacy clients can be supported, and a throughput survey using an 802.11ac client validates whether the WLAN can provide the required user performance.

So while 802.11ac offers significant advantages, there are a lot of factors to consider when adding it to a network. Fluke Networks offers the ability to detect,

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