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01- mobile communication intro - Coggle Diagram
01- mobile communication intro
Localization
process of computing the locations of the node
we need it to find location easier
need of 3 or more receivers
to get higher accuracy
wireless networks
wide
gsm,3G,4G,5G
metropolitan
WIMAX
local
WI-FI
personal
Bluethooth,RFID
body
body sensor networks
standards
IEEE
Institute of electrical and electronics engineers
IEEE-SA
IEEE standards association
global standards in broad range of industry
IEEE 802 standards
family of networking standards
operates on 2 osi layer
physical and datalink
Choosing the best techonology for your app
What Quality of service does your app need
Reliability
battery lifetime
latency
co-exsistence
tradeoffs slide 26
choice of frequency has effect on
RF range
maximum data rate
antenna design (size)
interference
regulations
pros and cons
pros
interoperability
many people work toghter
cons
less design freedrom
many compromises
many companies involved
2.4 Ghz ISM band
pros
same solutions for all markets
many channels with different rate
100% duty cycle
cons
range is shorter
rule of thumb
double the freq you half the range
many interference
sub 1 Ghz
pros
better range with the same environment source
better penatration through building
cons
lower freq means bigger anthennes
difficult to build one design that has all the bands
different bands in many countries
more regulations
RF Interference
metigate mechanisms
DSS
pick up when connection go through wall
wider bandwith required
increased sensitivity
freq agility
detects used channel and change the channel
freq hopping
keep hopping between freq in sequence (correct time synchoronization)
watch out that no device is sleeping
what effect RF performance
Antenna
gain, sensitivity to body effects
channel selectivity
selecting to specific channel to get the best
sensitivity
link quality that is acceptable
output power
transmission power is different depeding on the device (regulations)
environment
obstruction, reflections, multi path fading
range (link budget)
6db + is twice the distance
double the freq is half the range
topology
bus
star
good for localization
ring
mesh
tree
point-to-point
power Consumption
100% duty cycle
never sleeps
need for low active current
1% duty cycle
sleep current is relavent