There is nothing more frustrating than undertaking mission-critical work and having your Internet suddenly slow to a crawl. Even if your Wireless Local Area Network (WLAN) is configured appropriately, you may find your wireless throughput and capacity dramatically affected by interference – especially as you add capacity and latency-sensitive applications into the picture.

Clearly, it’s no longer just the microwave oven in the office kitchen causing problems – with the increasing number of Bluetooth and wireless enabled devices in use today, the issue demands a considered approach from those responsible for deploying or overseeing any network. What is worse, you could even have performed an RF sweep before deployment, and – given its often intermittent nature – still have missed sources of interference!

In fact, two of the most common causes of wireless interference are co-channel interference (CCI), and adjacent channel interference (ACI). The former arises when transmissions occur on the same frequency in the same area, causing devices to contend for available bandwidth. ACI, on the other hand, occurs when transmissions are delivered over an adjacent or partially overlapping channel, with the resulting channel-bleed generating noise and interference. Your APs basically get into a shouting match, to determine which one gets to control the frequency at any given time.

This sort of interference can often be self-induced, if appropriate channel planning has not been carried out. For instance, many believe that they can overcome interference by deploying a denser network of access points. While there is merit to this approach as a means of ensuring capacity through ‘spatial reuse’ of the spectrum, it does not provide true immunity from the issue due to the transmit signal power of each access point playing a major part in CCI interference.

While the introduction of 5Ghz networks and smart antenna technology in the 802.11ac standard have gone some way to alleviating the issue of channel interference, they are in no way a magic bullet. The best approach is rigorous planning for both your deployment and channel use, a good wireless policy to prevent or discover rogue devices, and the use of tools such as spectrum analysers and automated response-to-interference products.

For more on channel interference and how to plan around it, we recommend taking a look at this article fromNetwork Computing. If you’d like to know more about what we can do for your networks, comment or drop us a line – we’re happy to respond to any questions you may have.