No-Compromise Wi-Fi

13 Feb 2019

The wireless edge of the network has become ubiquitous, and so too have our expectations of a reliable and secure connection. As we have become used to the convenience of connecting wherever and however we want, we tolerate the flaws in a typical Wi-Fi connection – pauses in downloads, occasional drop-outs where we must re-connect, and lengthy waits as we try to join a public Wi-Fi network. For our personal browsing, we make a conscious compromise between convenience and reliability because apart from being frustrating at times, no real harm is done. But in a business environment, reliable wireless connectivity can’t be a compromise for critical operations, especially where it can be the difference between life and death.

• 1. Dynamic physical environments, like warehouses, where radio coverage is continuously being changed as objects are moved and removed. This makes multi-channel planning almost impossible, so the work-around is to deploy more APs. Unfortunately, this not only increases cost, but it introduces more radio interference, which reduces data throughput. 
• 2. Environments that must have reliable connectivity to mobile devices, like hospitals, where even a momentary loss of data connectivity can have a serious effect. As a wireless client moves, its connection will “roam” to another AP when it perceives a significantly more attractive signal. Unfortunately, this roaming process can sometimes be slow and disruptive as security credentials must be established or re-negotiated. Often this can manifest as an annoying lag on a VoIP call, or random artefacts in video. One solution is to use only wireless clients that support “fast-roaming” protocols, or intelligent bridging devices that handle the roaming on behalf of the client. Both these solutions add complexity and cost. 
• 3. Environments where there are many roaming wireless users, like schools, hospitals, public venues, etc. Multi-channel struggles to cope in these situations because only one client can talk to an AP at a time. So, having more clients associated with an AP means there is less time for each client to talk, so the effective bandwidth to each client is reduced. Adding more APs doesn’t always help because co-channel interference increases, which also reduces bandwidth. 

• 1. In a dynamic environment, Channel Blanket APs can be deployed in greater numbers than multi-channel APs because their single radio channel does not introduce interference. If greater bandwidth is required then the APs can be configured to support up to 3 blankets concurrently, which significantly increases capacity in dense AP environments. 
• 2. Channel Blanket has the advantage in an environment that requires reliable roaming too. With single-channel, all APs in the network appear as if they are a single AP, so the mobile client only sees that it is connected to one large AP. When the client moves, the Wi-Fi controller assigns it to a new AP, so the client is unaware of the “roam” and needs no special features to support it (e.g. fast-roaming protocols). Not only does this simplify the client, but it means the Wi-Fi connection is not interrupted by the move, and no latency is introduced, or data lost. Note that although new standards have been ratified to facilitate better roaming (e.g. IEEE802.11k/v/r), only high-end, modern wireless clients support these standards (e.g. iPhone6 with iOS7 and later). Clients that do not support these standards will still experience some disruption or data loss when roaming on multi-channel wireless networks. 
• 3. In an environment with a high client density, Channel Blanket can increase the available bandwidth by enabling more APs to be installed in the same area without introducing co-channel interference. Although this is possible with multi-channel too, Channel Blanket solutions require no channel planning so installation and management is much easier.