Friday, July 17, 2009

What is Wireless?



Wireless technology has come a long way since Guglielmo Marconi sent the first wireless transatlantic radio message on December 17, 1902 (Wikipedia, 2009). Today, wireless technology is used in almost every society around the globe. As wireless technology is not new to the world, nor is it new to healthcare. Cardiac telemetry systems of the 1970’s used wireless technology to measure electrocardiographs (Medical Connectivity, 2008). Although the use of wireless technology in healthcare is not new, we are currently witnessing a technical revolution in terms of the applications of wireless technologies within the healthcare sector. The old saying, “the sky is the limit”, truly applies to wireless technology in healthcare.

So what is wireless?

The term wireless implies that a system or device is continually connected without a direct physical connection. The connection may be to a server with data, the Internet, a network or a mobile communications system. Without cables, wireless systems use air as the medium for transporting data. Like wired systems, wireless data is available in “real time”, although wireless technologies limit the confines of space and distance. Wireless systems allow data to be shared between wireless and wired devices. The type of wireless system dictates how, when and where a wireless user may use the specific system.

Wireless systems use radio waves to send signals (Wifinotes, 2009). Modern wireless technology began with the invention of wireless local area networks (WLANs). These networks were refined in the late 1990’s to increase their speeds, security and ability to carry data. The term WiFi is used to describe a wireless network. A wireless connection can be between two or more devices. Personal computers, cameras and printers use this system. Wifi may also transmit data to larger systems for a business or geographical purpose. WiMax is the term used to describe metropolitan area networks. Global systems also use wireless technology and are often referred to as mobile communication systems or GSMs. Cell phones, pagers and global positioning systems (GPS) use GSMs. Bluetooth devices use wireless technology but over much shorter distances. Bluetooth may support up to 8 devices within a distance of 100 meters. In healthcare, this technology is often used during procedures with instruments sending a signal to a main terminal. An endoscopy exam is one example.

(Information retrieved from Wifinotes at Website
http://wifinotes.com/ )

WLAN

A wireless local area network (WLAN) works in much the same way as a wired local area network, but a WLAN allows devices to be connected without a wire.

Each device in a WLAN (desktop PC, PDA, laptop) is fitted with a radio transceiver (often called a LAN card or ethernet adapter). The transceiver sends and receives radio signals. Each transceiver has a permanent and unique identifier that serves as the device address; thus each wireless device has a unique address.

Data sent through a WLAN is carried in packets. These data packets contain:
1. the address of the sender
2. the address of the receiver
3. data

Data carried via a WLAN is not sent continuously; it is only sent when the transceiver detects an opening in the WLAN. Communication between WLAN devices falls into two types; peer-to-peer communication and infrastructure communication.

Peer-to-Peer WLAN
- data is broadcasted and received by all wireless devices within 300 feet of each other
- devices are constantly listening for signals and when one is detected a network is created
- there is no central access point

Infrastructure WLAN
- each device sends data to and receives data from a central access point (wall or ceiling mounted)
- data received by the central access point is resent to devices within a greater range

The majority of WLANs in the healthcare setting are of the infrastructure type
.

No comments: