Biomedical Engineering Reference
In-Depth Information
6
Radio-to-Fiber Repeater Placement
in Wireless
Local-Loop Systems
6.1 Introduction
Fixed-wire.systems.(e.g.,.telephone.twisted.pairs.and.coaxial.cables).are.no.
longer.the.only.option.for.providing.telephone.services..With.the.emergence.
of.a.new.technology,.the.wireless.local-loop. (WLL). system.is.now.possible.
for.telephone.networks.
The. WLL. system. employs. wireless. links. to. connect. subscribers. (equip-
ment. such. as. telephones,. fax. machines,. etc.). to. the. local. exchanges. in. the.
central.office.[5]..It.offers.services.that.include.voice,.fax,.data,.and.Integrated.
Services.Digital.Network.(ISDN).services,.and.so.on,.with.the.same.quality.
of.service.in.bit.error.ratio,.delay.time,.and.blocking.probability.as.those.pro-
vided.in.fixed-wire.systems.[7,18,19].
The.WLL.system.gives.a.telecommunication.infrastructure.that.not.only.
better. serves. the. demands. of. low. population. densities. such. as. in. urban/
suburban.or.rural.areas.[10,.22].but.also.is.a.good.solution.to.alleviate.the.dif-
ficulties.of.providing.telephone.services.in.isolated.areas.and.regions.subject.
to.natural.disasters.such.as.earthquakes,.floods,.and.hurricanes.[7].
There. are. two. types. of. WLL. systems:. narrowband. WLL. systems.
operating. under. 10. GHz. and. broadband. WLL. systems. operating. above.
10 GHz. [6].. In. this. study,. only. the. narrowband. is. considered.. Different.
technologies,. such. as. cordless. systems,. second-generation. cellular. sys-
tems,.satellite.systems,.fixed.wireless.access.systems,.and.so.on,.can.be.
utilized. in. WLL. systems. [2,11,12,15].. However,. most. of. the. narrowband.
WLL. systems. are. developed. using. cordless. and. second-generation. cel-
lular.systems.[18].
WLL. systems. have. a. number. of. advantages. over. fixed-wire. systems.
from. the. perspective. of. service. providers. and. subscribers. [3,7,8,16,18,20,21],.
including
.
1.. faster.deployment;
.
2.. low.installation.cost;
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