Introduction

Wi-Fi technology is a critical component of modern healthcare infrastructure, being integral for a variety of applications, from electronic health records and telemedicine to patient and visitor communications. This report considers Wi-Fi's operation on radio waves and its dependency on unlicensed RF spectrum, regulated in the UK by Ofcom.

This report provides an assessment of Wi-Fi performance metrics to explain how networks can support healthcare delivery across the NHS, considering the unique demands and complexities of each healthcare setting.

For an introduction to Wi-Fi and other wireless connectivity technologies see an introduction to wireless technologies in health

This report provides guidance on the measurement, analysis, and management of Wi-Fi performance metrics. These metrics are fundamental to the maintenance and improvement of Wi-Fi services and play a crucial role in healthcare delivery. Additionally, they must be recognised for their pivotal role in critical digital transformations. These transformations include the rollout of new electronic patient record (EPR) systems, the adoption of electronic bed management, asset tracking to enhance operational efficiencies in patient flows, implementation of wayfinding solutions, and strategies to reduce missed appointments.

Wi-Fi uses radio waves (also referred to as radio frequency or RF) to send and receive data. These are electromagnetic signals that travel through the air, just like the signals a radio uses.

Within the UK, Wi-Fi operates within unlicensed RF that is regulated by Ofcom for the following ISM bands: 

• 2.4GHz (2400MHz – 2483.5MHz) 

This frequency range is assigned into 13 channels, with each channel number referring to the centre frequency operating over 20MHz bandwidth. 

• 5GHz (5150MHz – 5925MHz)

This frequency range is assigned into 25 channels, with each channel number referring to the centre frequency operating over 20MHz bandwidth.

• 6GHz (5925MHz – 6425MHz)

This frequency range is assigned into 24 channels, with each channel number referring to the centre frequency operating over 20MHz bandwidth.

Unlicensed RF operates on the principle that anyone is free to use it. Unlicensed RF may be used by various non-Wi-Fi specific technologies within different NHS settings such as RFID tracking tags, CT/MRI or ultrasound machines, Bluetooth, Zigbee, wireless CCTV and other radio communications. As multiple devices can transmit and receive data within the same radio frequency range, there must be established protocols, or rules, to avoid interference on shared frequency between multiple devices.

Wi-Fi executes a protocol called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). This means that before a device can transmit data over the air, it must first listen to hear if the RF is clear (carrier sense) over shared unlicensed RF (multiple access). As Wi-Fi uses a shared medium where multiple devices can access the RF, there is a risk that a 'collision' may occur. Transmitted data does not 'collide' while in the air, collisions only occur when the receiving device receives multiple signals it cannot demodulate. This causes the transmitting device to retransmit data again.

Wi-Fi uses half-duplex mode, which means that devices can send or receive data at any given time, but not both simultaneously. The goal of Wi-Fi is to get on and off the RF as quickly as possible to allow the next available device to transmit, especially during busy periods or in areas of high density.