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October 2015

Care Connection: Ensure Wi-Fi Works
By Kevin Robinson
For The Record
Vol. 27 No. 10 No. 26

Wi-Fi has become critical in the health care environment, making the connected hospital a reality and bringing benefits to patients and providers. In fact, ABI Research predicts that 100% of health care facilities with more than 500 employees will have Wi-Fi networks in place by the end of 2016.

The perks of connectivity are changing health care forever. For example, by connecting medical devices to their Wi-Fi network, hospitals can improve clinical workflows through wireless access to real-time patient data. Additionally, Wi-Fi connects both general networking and critical applications, from infusion pumps and oxygen monitoring devices to real-time EMR access.

With the growing presence of connected devices and services, hospital IT administrators need to manage their networks 24 hours a day, seven days a week, 365 days a year to maintain a high quality of service (QoS). To ensure the best QoS, Wi-Fi deployments must be carefully planned during the entire life cycle, from the initial design to the operational management of a heavily used network. This includes maintaining network performance when enhancing functionality, such as adding support for new devices and applications or meeting increasing performance and traffic requirements. The following are several steps to ensure success throughout the entire life cycle.

Setting Up for Success

Connected devices are central to a smart hospital. As such, many factors must be considered before introducing a new type of device to a Wi-Fi network. For example, administrators must understand the device's networking performance requirements and characteristics. This breakdown enables administrators to determine the proper device-specific service level agreement in terms of network performance and needed functionality to handle traffic from the device and to assign it a security classification. A device's bandwidth needs, including total throughput, latency requirements, and data rates, also should be considered.

By taking these steps to assess devices that are to be included in a Wi-Fi network, health care organizations can ensure that access points (APs) and other devices are set to provide a seamless and optimized connected experience.

Channel Planning
Generally, Wi-Fi operates in three noninterfering, nonoverlapping frequency channels in the 2.4 GHz band, with up to 24 channels in the 5 GHz band. But in hospitals with multiple floors, Wi-Fi signals extend across levels, so both horizontal and vertical dimensions should be considered to avoid cochannel interference.

To reduce the risk of cochannel interference, IT administrators must plan the AP and channel deployment in concert with vendors, and address the particular physical specifications and the capacity and coverage requirements of the Wi-Fi network. APs within range of each other should be set to noninterfering channels, a task which may be difficult in the limited 2.4 GHz band. Moreover, IT managers should use both 2.4 GHz and 5 GHz bands to accommodate the large number of connections often found in a hospital.

In a hospital setting, the potential for interference looms heavy. Despite channel planning, interference can be caused by various sources, from wireless cameras to microwave ovens. Fortunately, radio frequency (RF) spectrum analyzers can assist in identifying such sources. Once identified, there are several strategies to mitigate the interference, including moving or removing the interfering devices, changing the channel of the interfering device, and changing the channel of the surrounding AP. A facilitywide RF usage policy also may help solve interference problems.

Multipath and Signal Distortion
Multipath transmissions occur when radio signals reach the receiver from various paths due to reflection or refraction. In a hospital, this can be caused by physical barriers such as metal diagnostic equipment (eg, X-ray and MRI machines). The signals, which are attenuated or amplified as they arrive in multiple converging wave fronts, sometimes act as destructive interference and cancel out other signals.

This is a huge deterrent for networks utilizing legacy Wi-Fi PHY/MAC deployments such as IEEE 802.11a, b, and g. However, it's actually beneficial for the newer IEEE 801.11n and ac standards because the latest standard-based devices use advanced multiple-input, multiple-output features to leverage the effects of multipath signals to increase range and overall throughput. For hospitals, the latter technology is highly recommended.

Maintaining High QoS, Enhancing Functionality
Besides configuration, the monitoring and measuring of the quality-of-experience indicators ensure Wi-Fi infrastructures maintain a high QoS. Delivering the best service to medical staff ultimately results in the best patient care.

This entails not only concentrating on steps that include design and configuration but also incorporating QoS features such as Wi-Fi Multimedia to improve the efficiency of traffic transmission based on priority and ongoing management that will keep IT managers attuned to end-user needs. Moreover, because of the sensitivity of some devices used in clinical activities, proactive network monitoring and reporting must be conducted in real time, including visibility into the performance of end-to-end networking components and APs. (Off-the-shelf tools are often available for these purposes.)

Any organization can reap the rewards of Wi-Fi infrastructures. All it takes is for IT managers to deliver a high level of reliability so that staff members are confident in the network's ability to meet user demands. To achieve this goal, organization leaders must proactively monitor, manage, and test key aspects of the Wi-Fi network through processes such as RF site surveys, device audits, and channel planning. Taking these steps is key for optimized networks, especially in clinically dependent, end-to-end, quality-of-experience environments such as health care facilities.

— Kevin Robinson is vice president of marketing for Wi-Fi Alliance, where he oversees branding, communications, market development, program marketing, and public relations. In addition, Kevin is responsible for driving the development of Wi-Fi Alliance's corporate strategy. The Wi-Fi Alliance's Healthcare Marketing Task Group also contributed to this article.