Flying Free: Bringing Wireless To The Wired

The role of business WLANs is changing: Businesses are shifting the entire corporate network to a WLAN to cover large areas and connect remote offices. Increased reliance on WLAN means handoff latency and weak signals are no longer acceptable when the network is carrying video and voice applications.

Extricom wants to enable triple-play and other services, such as voice, data, and video on a WLAN. To successfully support those applications, the WLAN's performance and resiliency must increase, but also remain affordable and easy to maintain. Extricom's wireless solution achieves that with a switch that puts all the access points on the same channel, using the same frequency.

The product uses all available Wi-Fi radio channels on every access point to create a continuous blanket of coverage. Within each blanket, there is seamless mobility with no handoff latency, no co-channel interference and robust connections similar to those in a wired network.

Separate channel blankets can also physically segregate different user types, traffic type and roles onto different channels to improve quality of service. A multilayer WLAN consists of multiple channel blankets. With two or more channel blankets operating on channels in the same band, users can simultaneously have a phone call on one channel and streaming video on another channel. Moving around doesn't drop the phone call or streaming video, and there is no fighting for bandwidth between applications.

Having all the access points on the same radio channel and the same frequency prevents interference because the switch decides on the packet level which access point a client should be connected to at that moment. Once a client is connected to the WLAN, it never hands off to a different channel. When the user moves within a different access point's range, the switch diverts the client's data connection to that new access point. The transfer is seamless; the client device does not encounter any lag time as the new access point kicks in. A software application has a screen display that shows which client devices are connected to which access points and indicates the transfer as it happens.

Extricom Interference-Free EXWO-404 WLAN Switch works only with a company's own access points. Because the UltraThin devices contain no software or storage, they are managed centrally by the switch. It handles centralized packet-by-packet processing and decides which access point to use based on real-time conditions whenever a packet is sent. The switch has a complete radio map of the network—which lets the switch know which access points are transmitting data and where the data are, allowing it to assess when and where to transmit, and through which point.

Conventional WLAN systems require extensive site surveys and cell planning so that access points are placed to meet radio frequency requirements. Because Extricom uses channel blankets, there are no cell points to consider.

The EXWO-404 Wireless Office system is an all-in-one package consisting of a WLAN Switch and four UltraThin Dual Radio Access Points. Priced at about $4,320, the system is designed for small networks, such as those found in a branch office or any other environment with limited coverage.