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fitting more APs or installing a relay device. In a situation whereby there are many Aps, a MC picks the closest AP that is
able to provide the best signal quality when the connection is established. Wi-Fi, or Wireless Internet, provides a unified
standard derived from IEEE 802.11 WLAN by the Wireless Ethernet Compatibility Alliance WECA for distinctive types
of wireless devices. APs are also known as hotspot which is generally functioning as connection distributors. Wi-Fi and
Bluetooth are similar in numerous aspects, however differences exists because of tradeoffs between data speed, coverage and
power consumption. As such, these lead to difference in device cost and size. In home networking, Wi-Fi technology is ideal
and is quite adopted in situations of off-site patient monitoring for individuals who are recuperating at their own homes,
whereby home networks can be conveniently utilized with little alteration.
2.2.4 Zigbee
ZigBee is a tiny digital device used for WPANS wireless per- sonal area networks which complies with the standards out-
lined by IEEE 802.15.4. ZigBee is simple to use and consumes little power. However, it cannot be used for intensive infor-
mation transfer because of its slow speed. As such, its functions are limited to wireless control and monitoring. As of now, a
worldwide standard operating frequency does not exist for ZigBee. 950 Mhz is used in Japan, 915 Mhz in USA, 868 Mhz
in Europe and 2.4 Ghz in many parts of the world. It is often seen as a basic adaptation of Bluetooth and is regularly utilized
in System on Chip Soc implementations. It is extremely cheap to the extent that a transceiver can be purchased for less than
US1 for every unit. It is also usually utilized as a part of secu- rity mechanisms, for example in smoke detectors and remote
control for air conditioner, as well as body area sensor networks as stated in Section 3.5. Zigbee Coordinator ZC serves the
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communication network while the Zigbee Router ZR transfers information between the gadgets
2.2.5 Cellular Networks
Mobile phone system is usually identified as cellular networks since the coverage region is made out of radio cells whereby
every single one is served by a Base Transceiver Station BTS. The BTS functions as directed by the service operator and as
supported by the cellular technology. Coverage area can be up- graded by creating additional cells. The use of cellular compo-
sition extends the capacity and lowers the usage of power during transmission besides enhancing the coverage area. One
of the key features of cellular networking is the ability of the users to move across cells without breaking connections which
is achieved by handover algorithms.
There are arrays of diverse technologies which are currently be- ing used around the globe. We shall discuss briefly the technol-
ogies that are in use today, while omitting outdated frameworks for example Time Division Multiple Access TDMA and Ad-
vanced Mobile Phone System AMPS cellular technologies. CDMA1900 1.9 Ghz represents Code Division Multiple Ac-
cess 1.9 Ghz. At the moment, USA still make use of an old digi- tal cellular communication system as there are only a few
operators who are authorized to operate at 800 Mhz before the FCC approval for 1.9 Ghz. CDMA can support multiple concur-
rent base stations which are on the same frequency channel.
2.5 G 900 Mhz: GSM Phase 2 + Global System for Mobile communication which is verified by the European Telecom-
munications Standards Institute ETSI is a system generally used all over the world as it offers easy roaming across the na-
tions with one single cellular phone. General Packet Radio Ser- vice GPRS is an extension of 2.5 G which supports an
