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be taken lightly as legal liability results in a major ramification in the healthcare industry, which can be observed from the long
terms and conditions following the reclamation of health insur- ances. To avoid the risk of legal consequences, a liability waiv-
er is often issued before the provision of healthcare facilities.
5.5 Measurement service quality
It is indisputable that quality holds the highest importance in the healthcare industry where services are now offered using wire-
less networks. Given this, potential problems regarding wireless networks will be examined for a high quality of service QoS
ALGAET et al 2014. Link outage is when wireless network is disconnected. Statistics are normally used alongside with the
theories on communication to describe the possibility of net- work performance as shown in Figure 2.1, using a receiver. Da-
ta is transmitted via a wireless network, and the common issues that may arise pertaining transmittance are Fong, 2003b:
Attenuation: reduce in strength of transmission ac-
cording to distance
Depolarization: lowering two separated signals from
varied polarizations caused by segment disruption
Interference: disturbance of signals due to other causes Noise: undesirable extra energy joined to transmittance
signal
Scattering: random radiation of signals when blocked
by physical objects In addition, various factors that degrade the strength of signals
are identified. This complicated process can be shown via the concept of interference. The reliability of wireless network can
be affected by interference which includes Stavroulakis, 2003, alade et al 2010:
186
Co-channel interference: or ‘crosstalk’ that resulted from the encounter of signals of other networks with
identical frequencies. Electromagnetic interference: or ‘radio frequency inter-
ference’ RFI that resulted from disturbance of other signals. It is a common method applied in radio jam-
ming for disrupting a wireless network through the emission of a similar frequency. It can also be resulted
from wavelengths projected from the sun.
Intersymbol interference: undesired communication among symbols that normally resulted from multipath, a
resulted impact identical to noise from the same signal in different time phases.
These demonstrate that there are several types of signal in- terference. Various features are used to determine the
strength of wireless network such as:
Bit Error Rate BER: indicates the errors occurred in bit stream blocks BER =
ሻ signifies that from statistics, one bit error is expected for a million bits transferred. However, higher
strength is required in e-health Schimizu, 1999 and BER must be improved by reducing the data rate or allocating sufficient
link margin. Link margin is the additional power to rectify the disruption of transmittance due to signal degradations. For in-
stance, a particular margin link is required for signal degrada- tion cause by rain. As BER measures data bit error, this
function also used to determine E
b
N
energy per bit to noise power spectral density ratio of networks. It is digitally identi-
cal to Signal-to-Noise Ratio SNR of analogue communica- tions networks or known as SNR per bit and usually ranged at
18–20 dB for a good transmittance.
