Contact tracing might not have been a familiar term a few months ago, but it is certainly on the public’s lips now. It looks set to underpin the effort of every country’s efforts to get back to something approaching normal following lockdowns introduced in an effort to slow the spread of the COVID-19 pandemic.
Contact tracing, it is hoped, will enable healthcare organisations, researchers and governments alike to rapidly identify who might have come into contact with individuals infected with the coronavirus – and isolate them in turn. It should enable people to go about their work and leisure lives safely and confidently, knowing that if they come into contact with somebody who then shows symptoms, they will be automatically alerted.
The challenge, of course, is how to actually deploy the technology needed to underpin contact tracing, and to do so in a way which is efficient, cost-effective, ethical and secure. And this is where mesh networking comes in.
A mesh networking primer
First, a quick reminder of what mesh networking entails.
Traditional networks are centralised, with each point on the network connecting to a single central point (a server). Decentralised networks involve those points or devices on the network connecting directly to each other – and therefore forming a ‘mesh’. They are not a new idea, but as smartphones have become increasingly prevalent, offering a ready-made collection of devices to form such a mesh, the possibilities of such networking have dramatically evolved. Smartphones come with Bluetooth connectivity built in, enabling them to communicate with nearby devices even when there is no mobile cellular or WiFi coverage available.
Mesh holds multiple advantages over traditional networks. First, the failure of an individual device does not cause a failure in the network – traffic can simply be rerouted. Second, mesh networks can support a much greater volume of traffic than traditional networks, because multiple devices are able to send and receive information at the same time. Third, it allows for truly wide and diverse coverage, and fourth, it can be deployed quickly and cost-effectively, thanks to its minimal infrastructure.
And all of these advantages are vital for creating a workable, reliable contact tracing solution.
Potential limitations of BLE
The various coronavirus contact tracing apps in development all work by masking the personal identity of each individual’s phone, but nevertheless recording the time they in proximity to otherphones by using Bluetooth Low Energy (BLE) Relative Signal Strength Indicator technology.
However, there are some concerns that this underlying BLE technology may lead to inaccuracies in locating devices which have been on contact within 2 metres and 15 minutes – generally accepted as the parameters for putting individuals at risk of passing on the infection. Wireless interference is a particular problem, because the more individuals in a particular area have such a contact tracing app on their phones, the more interference is created from other wireless systems, such as WiFi, which are using the same spectrum band.
Mesh technology can mitigate this problem through so-called ‘multi-hop technology’ which creates a much more robust and resilient architecture of device-to-device communication. It makes it much more likely that a phone will connect to other phones in the same area – and therefore much more likely that proximity and time spent near other devices will be accurately recorded.
Time will tell as to how effective the rollout of contact tracing apps are in reducing the impact of the COVID-19 pandemic, but regardless, mesh networking looks likely to play a significant role.
Find out about Wyld Network's work with NHS Highland and Highland Health Ventures to produce a specialist app that will provide safer environments and better communications by creating geozones using Mesh technology.