Causes of Co-Channel Interference in Hospitals

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Causes of Co-Channel Interference in Hospitals

What causes co-channel interference and what can hospitals do to deal with it?

As hospitals are extremely large and diverse and are full of various access points and medical and user devices, interference is always an issue that needs to be continually monitored. One form of interference that impacts hospital networks is co-channel interference.

Co-channel interference takes place when two access points within a network are on the same channel, causing interference that weakens the signal and thus provides problems to the end-user experience on the network.

Let’s take a deeper dive into what causes this form of interference and how it can be managed within hospital networks.

What causes co-channel interference?

Hospitals are made up of various network access points (APs), which are the devices that allow other Wi-Fi devices to connect to the network. All these APs can easily cause co-channel interference, which occurs when two of them are transmitting on the same channel and are in close proximity to one another. The interference then leads to weakened signal strength.

These other Wi-Fi clients are the leading cause of co-channel interference and many people still need to understand that co-channel interference is not static. It causes unnecessary airtime consumption but can be addressed with proper network management.

A similar problem within wireless networks is called adjacent channel interference. This happens when access points in close proximity are on overlapping channels or adjoining channels (as opposed to the same channel, as in co-channel interference).

Co-channel and adjacent channel interference are primarily issues within the 2.4 GHz band since this spectrum only has three channels that don’t overlap with each other, out of the 11 channels in this spectrum.

Because hospitals usually consist of several floors and wings, each of which may have an AP, these APs from the floors both above and below a given AP are in close enough proximity to cause interference, whether on the same channel or adjoining channels.

How to deal with co-channel interference

Fortunately, there are best practices to implement in a hospital wireless network that can address co-channel interference and keep it under control. For example, a simple solution in hospital networks with dense access points is to try to reduce the transmit signal power on each of the APs.

Another strategy is to move the AP to another channel or move it to the 5 GHz band. By turning off the 2.4 GHz radios in the dual-frequency APs, and instead relying on the 5 GHz radios within the APs, networks can better keep up with density demands. As mentioned above, there are more channels to access in the 5 GHz band, so co-channel interference can be reduced or even avoided.

The 5 GHz band can be used by 802.11a and some 802.11n products, and it’s less likely to experience this type of interference. This is large because there are 23 different non-overlapping channels, which makes a big difference compared to the three that the 2.4 GHz spectrum has. This way, there is a lot more capacity and significantly reduced the likelihood for co-channel or an adjacent channel interference.

Hospital network administrators should remember that 5 GHz bands don’t send signals as far as those coming from lower frequencies such as the 2.4 GHz band, but according to research, the throughput of 5 GHz networks is just as good if not better than 2.4 GHz networks. This point is often misunderstood and thus some people are hesitant to switch over to 5 GHz.

As many more devices continue to enter network areas, especially in hospitals, the concerns for wireless network administrators have been shifting from providing a wide range of coverage towards a larger capacity for coverage.

What is radio frequency spectrum management?

Another approach to managing interference is called radio frequency spectrum management (RFSM). RFSM incorporates tools that allow administrators to manage the different layers of a network by setting up channel assignments automatically, as well as setting up automatic transmit power levels.

While this system of tools can address many problems on its own, it often cannot make automatic decisions based on traffic that isn’t wireless network traffic – so additional interference problems can occur or fail to be factored into implementations.

7SIGNAL’s best-in-class wireless monitoring services can help you identify the causes of any co-channel interference and eliminate this problem. Our suite of passive and active monitoring tools ensure that your facility has consistent, strong Wi-Fi – often enabling you to spot and fix issues before any users are even aware of them.

7SIGNAL® is a leader in enterprise Wireless Network Monitoring. The 7SIGNAL platform is a cloud-based Wireless Network Monitoring (WNM) solution that continuously troubleshoots the wireless network for performance issues – maximizing network uptime, device connectivity, and network ROI. The platform was designed for the world’s most innovative organizations, educational institutions, hospitals, and government agencies and is currently deployed at Booz Allen Hamilton, IBM, Kaiser Permanente, Walgreens, Microsoft, and many others. 7SIGNAL continuously monitors the connectivity of over 4 million global devices. Learn more at www.7signal.com.

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