avoid interference from adjacent channels, for example 1ch, 6ch, and 11ch. In addition, in a medical facility, interference may also come from equipment on the floors above and below. Another key issue is the increase in the number
of devices relying on wireless LAN technology. These not only include the PCs and tablets used by doctors and staff, but patients’ smartphones and portable game consoles can cause radio interference or overload the network. Too many devices on the network results in difficulty in establishing a wireless connection and slow communication speeds. The most common problem with WMTS is no
wireless connection due to the radio signal being too weak. Causes include low battery voltage in the transmitter, improper antenna position, interference from other wireless equipment or noise sources, and attenuation of the signal due to additions and layout changes.
Figure 1: 2.4 GHz channel configuration and channel bandwidth
arge amounts of data, from images to text, need to be managed within medical facilities. This means efficient data
management, faster sharing and coordination of medical information, and improved communication among healthcare professionals, is essential. To address these needs, medical facilities are digitising medical administration and data, and introducing wireless communications using wireless LAN and Bluetooth technologies. Offering power-saving features, Bluetooth
is suitable for devices worn by patients and for medical devices that transmit and receive small amounts of data, such as pulse oximeters, blood pressure monitors, thermometers, electrocardiographs and electroencephalographs. Wireless LAN, meanwhile, delivers high-speed
communications to transmit images and video, ideal for equipment such as endoscopes and radiographic equipment. Wireless Medical Telemetry Systems (WMTS), also used within medical facilities, use dedicated frequency bands to minimise radio interference. With these, vital data – such as the heart rate (ECG), respiratory rate, body temperature, and blood oxygen level – of hospitalised patients is monitored at the nurses’ station. The equipment transmits radio signals to an antenna system in the patient room, which then sends the data to the central monitor for display.
For patients wearing sensors that collect
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biometric data, wireless communication is ideal as it makes it easy to set, add or relocate devices. However, problems such as communication outages and slow speeds can arise. A major issue in wireless LANs is the overlap
of radio channels used by multiple devices. Of the frequency bands used for wireless LAN, the 2.4 GHz band is supported by the largest number of devices. Thirteen channels are determined at 5 MHz intervals, from 2412 MHz to 2472 MHz. Since the channel bandwidth is 20 MHz, only three channels at 5-channel intervals can be used to
Communications problems occur in medical facilities primarily due to interference and attenuation, which can cause medical equipment to malfunction or suffer from communication disruptions. As this can potentially endanger patient safety it is important to identify and resolve the causes of such problems. Wireless communications can be identified by following a set of processes: • Use a simple measurement to check the strength of the radio wave. In a wireless LAN, the number of access points that can receive the data is also checked.
• For radio signals that are not strong enough, rearranging the radio equipment or changing the position of objects that could act as obstacles to radio propagation could improve radio signal strength.
• If problems persist, despite the signal
The height of the waveform represents the signal strength. The higher the waveform, the better the communication
The overlap of waveforms shows that multiple wireless LAN signals are using the same or nearby channels. Weak signal strength and signals that overlap other wireless LANs can lead to deterioration in the communication quality, such as the inability to increase the communication speed
Figure 2: Example of wireless LAN radio wave environment measurement using free software
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