LTE FDD Radio Link Budget Principle
LTE FDD Radio Link Budget Principle
Huawei Technologies
Technologies Co., Ltd.
All rights reserved
2018-6-14
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LTE FDD Radio Link Budget Principle
1 Introd
Introducti
uction
on
The purpose of this document is to illustrate the link budget principle and at the same
time provide detailed introduction to certain fundamental link budget parameters.
2 LTE Link Budget
The link budget calculations estimate the maximum allowed path loss between the
mobile and the base station. The maximum path loss allows the maximum cell range
to be estimated with a suitable propagation model, such as OkumuraHata. The cell
ra
rang
nge
e give
gives
s the
the nu
numb
mber
er of ba
base
se stat
statio
ion
n site
sites
s re
re!u
!uir
ired
ed to co
cove
verr the
the targ
target
et
geographical area. The LT" Link #udget workflow is showed in figure $.%.
Start
Input Data
Calculate EIRP and
"inimum Recei$er Sensiti$it%
Calculate do!nlink "#PL
Calculate uplink "#PL
#nd Cell radius
#nd Cell radius
"in &uplink' do!nlink(
E))ecti$e cell radius
Calculate site numer
End
&igure $.% LT" Link #udget 'orkflow
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LTE FDD Radio Link Budget Principle
2*1 "a+imum
"a+imum #llo!ale
#llo!ale Pat,
Pat, Loss
Loss
Link #udget is the first step for radio network dimensioning. &or an actual radio
ac
acce
cess
ss ne
netw
twor
ork,
k, th
the
e effec
effecti
tive
ve co
cove
vera
rage
ge of e(od
e(ode
e # de
depen
pends
ds on no
nott on
onl)
l) the
the
coverage environment but also the T* power and +x sensitivit) of e(ode # and ".
-ince the properties of e(ode # and " are different from each other considerabl),
the actual permitted uplink and downlink path loss var) too. #ecause the actual
effective coverage range will depend on the lower value of them, it is necessar) to
calculate the permitted maximum allowable propagation path loss of both uplink and
downlink. -ome A/L uplink budget parameters are briefl) illustrated in &igure $.%.%
/PLI. B/D-ET
t,er -ain
Slo! )ading margin
#ntenna -ain
t,er -ain
/E #ntenna -ain
Inter)erence margin
"argin
Loss
Bod% Loss
/E Transmit Po!er
&e*g* 20dBm
20dBm((
#ntenna-ain
Penetration Loss
Pa
t,
Pat, Loss
Lo
ss
Cale Loss
.ode B #ntenna -ain
CaleLoss
.odeB
Sensiti$it%
Penetration
e.odeB reception sensiti$it%
&e*g* 3114dBm
3114dBm((
Loss
&igure $.$.% plink #udget
The aximum /ath loss 0A/L1 of downlink and uplink can be described b) the
formulas below2
*APL  ERP(dB.$ - 10  Log10 (12  N RB $ - R/ )en!iti"it+ ,o.po!ite (dB.$ 
Ant'ain(dBi$  ,aleLo!! (dB$  Bod+Lo!!(dB$  IM (dB$ - PeneLo!!(dB$ - )F*(dB$  %%&'
'here2
MAPL 2 aximum path loss 0d#1
EIRP 2 "ffective 3sotropic +adiated /ower 0d#m1
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LTE FDD Radio Link Budget Principle
PeneLoss 2 /enetration Loss 0d#1 0re!uired for indoor
indo or coverage1
SFM 2 -low fading margin 0d#1
HHOGain 2
Hard Handover 4ain 0d#1
N RB 2 (umbers of +e!uired +esource #lock
2*2 "ain L
LTE
TE Link Budget Parame
Parameters
ters
3n the following sections, a detailed description of the main parameters used in link
budget is provided.
$.
$.$.
$.%
% "3
"3+/
+/ pe
perr -ub
ubca
carr
rrier
ier
"3+/ means the "ffective 3sotropic +adiated power at antenna, calculated including
cable loss, antenna gain, bod) loss etc. and effect b) TA used or not. The formula
is as below2
ERP (dB.$  T *a/ po3er

Ant'ain  ,ell Edge Boo!t - Bod+lo!!- ,aleLo!!
The modulation scheme of LT" is O&5 0Orthogonal &re!uenc) 5ivision1.O&5 is a
modulation multiplexing technolog) divides the s)stem bandwidth into orthogonal
subcarriers. The "3+/ per -ubcarrier means averaged "3+/ per subcarrier and have
little difference for uplink and downlink.
&or downlink "3+/ per -ubcarrier is ax T* power averaged in total bandwidth. This
is depending on the number of subcarriers at total bandwidth.
EIRPPersubcarrier

ERP - 10  Log10 (12  TotRB4u.$
&or uplink
uplink "3+/
"3+/ per -ubcarrie
-ubcarrierr means
means ax T* power
power averag
averaged
ed in num
numbers
bers of
subcarrier used,
EIRPPersubcarrier


ERP - 10  Log10 (12  5LRB4u.$
Cable Loss
The cable loss value depends on the cable length, cable thickness and fre!uenc)
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LTE FDD Radio Link Budget Principle
band. The cable Loss for downlink at e(ode # side is also related with TA used or
not.
&or arco cell with TA in use
,aleLo!!(DL$  ,aleLengt  Lo!!1008100  7u.perLo!!AnttoT*A

7u.perLo!!T*AtoB)

n!ertL
&or arco cell without TA in use6
,aleLo!!(DL$  ,aleLengt  Lo!!1008100  7u.perLo!!6
Table $.$.%：T)pical cable Loss 0%77m1
Insertion loss6177m
Si5e
877"5
2177"5
2977"5
%8$9
:.;<:
%7.=:%
%$.7=
%8$9
%7.;>%
%?.%>@
$7.%%
@8?9
>.>$<
<.:@?
:.$@
@8?9
>.:@:
:.$;:
:.?=
<8;9
$.;:<
;.>;$
;.?$?
%>8?9
$.%=>
>.@=?
;.$7?
$.$.$
$.$
.$ +ec
+eceiv
eiver
er se
sensi
nsitiv
tivit)
it) /e
/err -ub
-ubcar
carrie
rierr
+receiver sensitivit) is defined as the minimum signal strength that
th at can demodulator
b) the receiver. The general formula is2
Re ceiverSensitivit

ThermalNoise  E S 8 N 0

Nf
The +eceiver sensitivit) subcarrier is2
Recei"er !en!iti"it+ ,o.po!ted  Ter.al noi!e (dB.8%:$  10 9 lg()ucarrier and
and$$  4F  E!8
$.$.> "s8(o（-3(+
-3(+）
）
"s8(o is the -ignal to 3nterference and (oise +atio as experienced b) the detector.
The factors 3mpact "s8(o including2
%. +adio "nvironment 0e.g. "T>1
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LTE FDD Radio Link Budget Principle
$. &re!uenc) #and 0e.g. $:77H1
>. C-, C-B Code bits Code rate.
;. +# 0+esource #lock1 number
<. #L"+ 0e.g. %7D1
$.$.; #od) L
Lo
os s
#od) loss is the loss at " due to the presence of human bod). T)pical value is >d#
for voip. &or services of data rates, no bod) loss is taken into account considering
that terminals are usuall) held kept a distance from the subscribersE bod).
$.
$.$.
$.<
< /e
/ene
netr
trat
atio
ion
n Los
Loss
s
'hen indoor coverage is re!uired to coverage b) outdoor macro (ode#s, buliding
penetration loss needs to be considered. #uilding penetration loss is related to such
fact
fa
ctor
ors
s as in
inci
ciden
dence
ce an
angl
gle
e of th
the
e radi
radio
o wave
wave,, the
the build
buildin
ing
g constr
construc
ucti
tion
on 0the
0the
construction materials and number and sie of windows1, the internal building la)out
and &re!uenc). #uilding penetration loss is highl) dependent on specific environment
and morpholog) and varies greatl). &or instance, the wall thickness in -iberian tends
to be larger than that of -ingapore in order to resist coldness and hence the formerEs
building penetration loss is correspondingl) larger.
3n add
additi
ition,
on, someti
sometimes
mes vehicul
vehicular
ar covera
coverage
ge ma) be re!uir
re!uired
ed and conse!
conse!uent
uentl)
l)
vehiculare penetration loss also needs to be included in link budget process. 3n fact,
onl) one penetration loss, the maximum of building penetration loss and vehicular
penetration loss, is included in link budget. -ince t)pical vehicular penetration loss is
around ?d# which is smaller than building penetration loss, building penetration loss
rather than vehicular penetration loss is usuall) included in link budget process.
$.
$.$.
$.:
: 3n
3nte
terf
rfer
eren
ence
ce a
arg
rgin
in 03
0311
3nterference
3nterf
erence margin
margin is the re!uired margin
margin in the link budget due to the noise rise
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LTE FDD Radio Link Budget Principle
caused b) s)stem load 0the noise rise due to other subscribers1.The higher the
s)stem load, the larger the interference margin.
$.
$.$.
$.@
@ -&
-&
 0-l
0-low
ow &
&ad
adin
ing
g a
arg
rgin
in11
The
Th
e lo
log
g no
norm
rmal
al fad
fadin
ing
g marg
margin
in 0als
0also
o kn
know
own
n as slow
slow or sh
shado
adow
w fadi
fading
ng marg
margin
in11
corresponds to the variation in mean signal level caused b) shadowing effect of
ph)sical environments such as buildings and hills.
The fading margin is the amount of margin necessar) to achieve the re!uired area
reliab
reliabili
ilit)
t) for a given
given sta
standa
ndard
rd deviati
deviation.
on. Obviousl
Obviousl)
), the hig
higher
her area
area cov
covera
erage
ge
reliabilit) re!uires the larger -&. 3n addition, the value of standard deviation will
also influence
influence the re!uired fading margin and the larger the standa
standard
rd deviation, the
larger the re!uired -&.
r
i t
s
P o b a b il y D e n t
i y
Coverage Probability:
Coverage Probability:
P COVERAGE (x) = P [F(x) > Fthreshold 
P COVERAGE (x) = P [F(x) > F threshold 
SF" re:uired
!itho"t #F$
!ith #F$
Received Signal Level [dBm]
F
threshold
$.
$.$.
$.?
? /r
/rop
opag
agat
atio
ion
n o
ode
dell
The propagation models are the basis of coverage planning. 4ood models ensure
the
th
e prec
precis
isio
ion
n of plann
plannin
ing.
g. The
The prop
propag
agati
ation
on mo
model
dels
s are
are us
used
ed to fore
foreca
cast
st the
the
influences of terrains and artificial environments on path loss and affected b) the
s)stem
s)s
tem working
working fre
fre!ue
!uenc)
nc).. 5iffer
5ifferent
ent models
models have differ
different
ent wor
workin
king
g fre!ue
fre!uenc)
nc)
ranges. All available /ropagation odels can be used for LT" link budget are listed
in the following table
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LTE FDD Radio Link Budget Principle
"odel
#pplicale Range
#and2$.<8>.<8<.?4H, Antenna height %7F?7m
-tanford A8#8C odel
Cell radius G%7km, suburban scenario
#and2 %<77F$777H , antenna height >7F$77m
Cost$>%－Hata odel
Cell radius %F$7km
#and2 ?77F$777H , Antenna height ;F<7m
Cost$>%'3 odel
Cell radius 7.7$F7.<km
#and2 %<7F%777H , Antenna height >7F$77m
OkumuraHata odel
Cell radius %F$7km
-/ odel
All band after calibration
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