UPLINK
BEAMFORMING
FOR
THE
FDD
MODE
OF
UTRA
Xa ie
Mes e,
Ju ie
R.
Fonollosa,
G ego i
Vazquez
Depa men
o
Signal
Theo y
and
Communica ions
Uni e si a Poli ecnica
de
Ca alunya
c/Jo di Gi ona, 1-3,08034 Ba celona,
SPAIN
Phone:
+34
93
4017052
Fax:
+34
93
4016447
e-mail:
[
mes e,
ono, g ego i]@gps. sc.upc.es
ABSTRACT
This pape p esen s some link le el simula ion esul s o he
e alua ion o aclap i e an ennas in he uplink o he FDD mode
o UTRA. Two amilies o algo i hms we e ini ially conside ed,
he basic di e ence be ween hem being hei abili y/disabili y
o supp ess he con ibu ion om WCDMA di ec ional
in e e ing sou ces. Two dis inc schemes we e es ablished
as
ep esen a i es o each amily and hei pe o mance was
e alua ed in p esence o some illus a i e in e e ing scena ios.
In he ligh
o
he esul s i is shown ha ime- e e ence
beam o ming algo i hms su e om se e e beampa e n
dis o ion e ec s when applied
as
such. This in u n causes
ha sh pe o mance deg ada ion in e ms o aw
BER,
especially
a high
SINR
le els. I is shown ha hese sho comings a e
essen ially caused by he uplink mul iplexa ion o he a ic
channel, which1 is seen by he base s a ion
as
a
powe ul
in e e ing souce coming om he di ec ion o a i al o he
desi ed use .
1.
INTRODUCTION
The i s aim
o
he wo k p esen ed he ein was
o
e alua e he
con enience o a ay-p ocessing in e e ence canceling schemes
in ypical W-CDMA scena ios. Clea ly, he pe o mance o
such a chi ec u es will depend s ongly on bo h spa ial
dis ibu ion
and
empo al s uc u e o he ansmi ed signals.
Since he analy ical modeling o hese e ec s becomes
somewha bu densome,
a
i s app oxima ion o he p oblem by
means o ex ensi e simula ions seemed mos app op ia e.
The e alua ion p ocess was ca ied ou ollowing
FRAMES
ecommenda ions
as
desc ibed in
[2].
Thus he “Ac ual Value
In e ace” (AVI) was chosen
as
he
mos
sui able connec ion
be ween link-le el and sys em-le el simula ions. The echnique
es ablishes ha he link le el simula ion esul s should be
measu ed in
a
bu s -by-bu s basis
so
ha he sys em simula o
unde akes all coding and link le el adap a ion. Thanks o ha ,
all adio esou lce managemen algo i hms (ha ing
an
ac i a ion
pe iod highe han bu s du a ion) can be accu a ely simula ed
on he sys em le el pla o m.
2.
(CHANNEL AND SIGNAL, MODEL
We deno e
x( )
(Pxl
column ec o ) he ecei ed snapsho a a
pa icula ime ins an
.
I
a&)
ep esen s he ansmi ed
This wo k
was
pa ially suppo ed by he Eu opean Coinmission unde ACTS
P ojec
AC347
SIJNBEAM,
he Spanish Go e nmen
(TIC96-0500-C10-01,
TIC98-0412, TlC98-0703) and he Ca alan Go e nmen CIRlT 1998SGR-0008
1.
(analy ic) signal coming om he s- h mobile s a ion, i s
con ibu ion o he ecei ed snapsho can be modeled
as
ollows:
being g,,
a
complex p opaga ion gain and
s,,( )
a
ime- a ying
supe posi ion o s ee ing ec o s. This gene alized s ee ing
ec o
s,,( )
-as i is commonly e e ed o in he li e a u e-
inco po a es he angula in o ma ion o he channel and
depends on ime due
o
he Dopple e ec .
In he sequel we will assume ha
1)
he ecei ed signal is
p ope ly sampled a
a
mul iple o he chip a e
(Nsc
sa nples/chip) and
2)
pe ec synch oniza ion wi h he use o
in e es has been a ained al eady. Now, ga he ing
M
consecu i e snapsho s o he ecei ed signal
a
he base s a ion
in o
an
AhP
ma ix
X,
we ha e:
x
=
[x(o)
X(TS)
...
x((M
-l)Ts)lT
wi h
Ts
deno ing he sampling pe iod. Le
us
now in oduce an
MxL
segmen o con olu ion ma ix:
d((L-1)Nsc
+1)
d((L
-
2)Nsc+l)
.’.
d(1)
d((L
-~)Nsc
+
2)
d((L
-
~)Nsc
+
2)
d((L
-1)Nsc
+
M)
d((L
-
2)Nsc
+
M)
...
d(M)
gene a ed om
M+(L-1)Nsc
samples o he desi ed use ’s
aining sequence
d( )
ansmi ed in he Con ol Channel
(PDCCH) -o
a
epe i ion he eo whene e
M+(L-1)Nsc
is
bigge han he pe iod o he aining sequence-. Upon he
de ini ion o an
LxP
ma ix including he wo-dimensional
disc e e
(1
sample/chip) channel impulse esponse:
(4)
we can exp ess he spa ial- empo al ecei ed signal ma ix
as:
X=DH+W
(5)
whe e
W
(MxP)
includes no only spa ial- empo al backg ound
noise bu also he con ibu ion o signals ansmi ed om o he
mobile s a ions
as
well
as
a ic channels embedded in he
desi ed use ’s da a s eam. P o ided ha he leng h o he
channel assumed a he ecei e (L) is no su icien ly la ge o
cope wi h he whole delay sp ead
o
he adio channel, he la es
e lec ions
o
he incoming signal a e assumed
o
be included in
his noise e m.
0-7803-5565,-2/99/$10.00
0
1999
IEEE
867
3.
UPLINK ALGORITHMS
UNDER
TEST
The main pu pose o he conside ed simula ions was o
in es iga e he in luence o di e en ep esen a i e W-CDMA
in e e ing scena ios on he pe o mance o con en ional
adap i e an enna sys ems. The objec i e was o quan i y he
po en ial ad an ages o in e e ence canceling schemes in on
o pu ely di e si y combining a chi ec u es. Thus, wo di e en
amilies o algo i hms we e conside ed, each one eso ing o a
dis inc p esump ion conce ning he spa ial na u e
o
in e e ence.
Figu e
1.
Vec o ial Rake Recei e
The i s scheme unde conside a ion, he eina e e e ed o as
V-Rake Recei e
(Figu e
l),
was chosen as ep esen a i e o
he amily o algo i hms which do no ake in o accoun he
p esence o di ec ional in e e ing sou ces. The scheme can be
basically shown o be he op imum de ec o om a maximum-
likelihood poin o iew when only omnidi ec ional Gaussian
noise is p esen in he scena io. Assuming ha he componen s
o he ma ix
W
a e join ly Gaussian-dis ibu ed, he ecep o
can be de i ed om he maximiza ion o he ollowing
likelihood unc ion:
?,I
= ec"(X-DH)R-,' ec(X-DH)
(6)
wi h
R,
he
MPxMP
co a iance ma ix o
ec(W),
and
0
and
ec()
deno ing he K onecke p oduc and he column-wise
ma ix s acking ope a ion espec i ely. A e some manipula ion
o
(6)
we ge :
?,I
= ecH(X)R: ec(X)
+2Reb]+
(7)
+ ecH
(D)R ec(D)
whe e we ha e de ined:
y
=
ecX(DH)R: ec(X)
(8)
R
=
(H*
61~
)R;(H~
61,)
wi h
Inn
he
MxM
iden i y ma ix. This o mula ion allows
sepa a ion o he combining pa o he ecei e om i s
subsequen da a-de ec ion pa . P o ided ha noise and
in e e ence can be conside ed spa ially and empo ally
unco ela ed,
y
becomes equal o (up o a scala ac o ):
y
= ecH(DH) ec(X) = [(DHIXX]
(9)
I we conside he ollowing decomposi ion o he channel and
inpu signal ma ices:
H=[h,...h,]
x
=[XI
...
x,]
he scala
y
can be exp essed in he ollowing way:
P
y
=
zh DHxp
p=i
Each e m
hXDHX
can
be
in e p e ed as he ou pu o a Rake
ecei e ma ched o each an enna channel impulse esponse.
In
conclusion, he op imum ecei e esul s in he scheme he ein
ega ded as he
V-Rake Recei e
(see Figu e
1).
Ye one issue
emains open: since he channel impulse esponse
H
is no
known, i mus be es ima ed om he incoming da a. An
ML
channel es ima e can be ob ained aking de i a i es o he cos
unc ion
(6)
wi h espec o
ec(H*)
and o cing he
co esponding g adien o be ze o:
PP
om whe e we ob ain:
ec(H)=
[(IL
ODH)R;(I,
@D)Y(IL
@D")R;' ec(X)
(13)
Finally, o he
V-Rake Recei e
conside ed he e:
H
=
(D~D)-'D~x
(14)
The app oxima ion o empo al unco ela ion o in e e ing
componen s
o
he inpu signal seem easonable as long
as
we
deal wi h digi ally modula ed signals sampled a he chip a e.
On
he con a y, hei spa ial whi eness can no
be
so
easily
jus i ied and will depend s ongly on he ac ual scena io unde
conside a ion.
A
mo e sensible app oxima ion, judging by
conclusions d awn om measu emen campaigns in
[7],
is o
conside ha he s uc u e
o
he dis inc gene alized s ee ing
ec o s
sI
in
(4)
does no a y in obse a ion in e als sho e
han he delay sp ead o he mobile adio channel. This is
equi alen o he app oxima ion:
H
=
has;
ec(H)
=
so
@
ha
whe e
ho
and ep esen he equi alen one-dimensional
channel impulse esponse and gene alized s ee ing ec o
espec i ely. Subs i u ion o
(15)
in o
(8)
leads o:
y
=
(sa
63
ha)H
(I,
6
DH)R;' ec(X)
(16)
o , a e some algeb a:
whe e, by i ue o he spa ial- empo al sepa a eness
app oxima ion, we ha e decomposed he non-desi ed signal
co a iance ma ix in o i s spa ial and empo al componen s
R,
=
R,
@
R,
. We obse e ha he op imum combining p io
o he sequence de ec ion collapses in o wo sepa a e s ages: a
spa ial s age, in which he incoming snapsho s a e p ep ocessed
by he op imum beam o ming (in he sense ha i p o ides
maximum Signal o In e e ence plus Noise Ra io
SINR
a i s
868
ou pu ); and
a
i empo al s age, which can be in e p e ed as
a
single Rake ecei e .
In his con ex , he second algo i hm unde es - he so-called
Ma ched Desi ed Impulse Response
MDIR
Recei e
[
8][3]
(Figu e
2)-
eso s o he sepa a eness app oxima ion in
(15)
in
o de o p o ide he ML es ima ion o he ansmi ed da a, he
beam o me weigh s and he equi alen channel
he
Assuming
Gaussiani y o he non-desi ed in e e ences he log-likelihood
unc ion o he ecei ed da a a e he spa ial p ocessing can be
exp essed (up o
a
cons an ) as:
{=(Xb-Dh)HRi (Xb-Dh)
(18)
whe e we ha e conside ed ha he channel impulse esponse
a e he beam o ming p ocess
h,
he da a, and he beam o me
i sel
b
a e all de e minis ic quan i ies. As al eady discussed, i
seems easonable o assume he spa ial co a iance ma ix is
close o he iden i y
so
ha he ML cos unc ion u ns ou o be
a mean squa e e o measu e:
{
=
llXb
-
Dhll*
(19)
In o de o a oid he i ial solu ion an addi ional cons ain
mus be imposed. Fo ins ance, one may se he powe
associa ed wi hi he aining sequence a he ou pu o he
beam o me equal o cons an :
bXHD(DHD)DHXb
=
1
(20)
The eby, using he Lag ange mul iplie s me hod he solu ion
may be shown o be [3]:
XHXb
=
am,,XHD(DHD)-'DHXb
(21)
h
=
(DXD)-'DHXb
Thus, he beam o ming weigh ec o is ound
as
he
eigen ec o co esponding o he minimum gene alized
eigen alue o he ma ix pencil
[x~x,
X~D(D D lD /x].
Since his eigen alue is equal o he in e se o he ou pu SINR
minus one, he solu ion is yielding op imali y in e ms o SINR
be o e he Rake ecei e .
4.
SIMULATION
ASPECTS
The main di icul y ha a ises when simula ing a W-CDMA
en i onmen esides in aking in o accoun all possible bi a es,
and consequen ly sp ead ac o s, ha migh be in ol ed in
an
ac ual scena io. In o de o o e come his p oblem wo di e en
kinds o use s we e de ined, he di e ence be ween hem being
basically he ype o se ice ha hey equi e: High Bi Ra e
(LBR) and Low Bi Ra e (HBR) use s. The o me a e supposed
o ha e a highe bandwid h demand and, consequen ly, an
ac ual mobile ne wo k will be capable o handling
a
high
numbe o LBK use s whe eas he numbe o mobiles equi ing
a HBR se ice will be limi ed. Fu he mo e, he highe he bi
a e, he mo e ansmi ed powe is needed in o de o p ese e
a
gi en quali y
o
se ice. All his sugges s ha LBR use s can be
p ope ly modeled
as
omnidi ec ional
Gaussian
noise.
In
ou
case,
a
cons an sp ead ac o
(SF)
was assigned
o
all
HBR
use s i espec i ely o whe he hey cons i u e desi ed o
in e e ing sou ces.
Conce ning he signal gene a ion in he simula ions, each
senso equency-selec i e channel was modeled wi h a apped
delay line o ime- a ying coe icien s as shown in
(1).
Pa icula ly, he models e e ed o as
Ou doo o Indoo and
Pedes ian
and
Vehicula
in
[6]
we e conside ed o he
gene a ion o he channel equency selec i i y, whe eas he
angula app oach p esen ed in 171 was used o cha ac e ize he
angula dispe sion o he p opaga ion p ocess. Thus each la -
ading componen o he mobile channel was gene a ed using a
ay model, whe e he numbe o impinging wa e o ms was se
equal o a Poisson andom a iable (mean equal o
25
ays).
In
addi ion, a Laplacian Powe Angula Spec um was conside ed,
along wi h a Gaussian dis ibu ion
o
he di e en di ec ions o
a i al o each use . The Powe Angula Sp ead was ixed o 8
deg ees o
all
aps and scena ios. The mobile speed was se o
3km/h
and
120km/h
o he Pedes ian and Vehicula models
espec i ely. Acco ding o he Ac ual Value In e ace, he
simula ion du a ion was se equal o he minimum powe
con ol ac ualiza ion pe iod, namely
0.625ms.
n
XI@)
Beam o ming
Design
1
,,
I
Me ic
I
T aining
Sequence
D
h
Figu e
2.
Ma ched Desi ed Impulse Response Recei e .
All he a ay-p ocessing algo i hms we e simula ed on a linea
equally spaced a ay o
8
an ennas, in which he in e elemen
sepa a ion was se o hal wa eleng h a he ca ie equency
(1950
MHz). All mobile angula loca ions we e a bi a ily se
by a uni o m andom a iable wi hin
[-60,601
deg ees, i.e.
120
deg ees sec o iza ion was assumed. Each use was supposed o
gene a e
a
single Dedica ed Physical Da a Channel (DPDCH)
oge he wi h i s associa ed Dedica ed Physical Con ol Channel
DPCCH (see 191 o de ails o he modula ion o ma s).
5.
SIMULATION RESULTS
Two in e e ing scena ios we e simula ed o each powe delay
p o ile model, one wi h a single domina ing HBR in e e ence
and ano he wi h i e. Apa om he a ay beam o ming
algo i hms p esen ed in sec ion
3,
a single-senso Rake ecei e
was conside ed o compa ison pu poses.
Uplink esul s a e depic ed in e ms o aw (uncoded) BER in
Figu e
3
and Figu e
4.
Al hough simula ions ook in o accoun a
high
ange
o
LBR
powe ( e lec ed in
he
Eb/No a io), only
esul s wi h Eb/No=lOdB a e p esen ed he ein. No e ha he
BER is always exp essed as a unc ion o he ins an aneous
Eb/Io pe senso (i.e., ecei ed by a single an enna and
869
measu ed wi hin an ac ualiza ion pe iod o he as powe
con ol).
Thanks
o ha , a con en ional planning ool can
di ec ly use hese esul s and he e o e dis ega d he exis ence
o adap i e an ennas.
Pedes ian, 115 inle eie s. EbINo-10
dB
100
I
'
'
'Q
Smole-senso
Rake
I
...
.,
..
.............
:I
-"
...............
.........
0
5
10
15
20
25
1
o-~
-15 -10
-5
Eblia
pe
senso
[dB1
Figu e
3.
Uplink
esul s
o
he
Pedes ian Channel Model.
Vehicula , 115 In e e e s, EblNo=lO dB
P
io
5
H
10
0
5
10
15
20
25
lo-+
-15
-10
-5
Ebllo
pe
senso
[dB]
Figu e
4.
Uplink esul s
o
he Vehicula
Channel
Model.
Compa ing he pe o mance
o
he p oposed algo i hms, he
MDIR ecei e gene ally a ains he bes esul s in e ms o
equi ed Eb/No and Eb/Io o a pa icula aw BER in he ange
o in e es (usually
om
lo-'
o
10.'
o
aw
BER).
This
is
a
logical esul , since nei he he V-Rake algo i hm no i s single-
senso coun e pa ake in o conside a ion he p esence o
in e e ence, which has
a
mos de imen al e ec on he ecei e
pe o mance. No e howe e ha o high Eb/No o Ebb0 le els
he Mul isenso Rake ecei e ac ually ou pe o ms he MDIR
scheme, he eason o ha being basically wo old. Fi s , he
MDIR s a egy bases i s ope a ion upon he adap a ion o a
na owband beam o me , an app oxima e solu ion o he
impai men s in oduced by he ime-dispe si e channel. Second,
non-ideal es ima es o he co ela ion ma ices a e bound o
o igina e signi ican pe o mance losses, especially when he
powe o he ecei ed signals is high enough.
The
loss
in oduced by he app oxima ion by he use o a
na owband beam o me ins ead o an a ay
o
FIR il e s
(app oach equi alen o ha
o
a wideband beam o me )
becomes ully jus i ied by he on -end complexi y educ ion
ha he o me en ails. O mo e se ious conce n is he
deg ada ion in oduced by impe ec es ima ion o he
co ela ion ma ices needed in he MDIR algo i hm. Basically,
he eason o his beha io is ha he a ic channel
mul iplexed wi h he pilo
is
seen by he base s a ion as an
in e e ing signal coming om he e y same angula di ec ion
(no e ha only he aining sequence componen is iden i ied
as
'desi ed sou ce' by he beam o ming algo i hm). This leads o a
deg ada ion o he desi ed signal es ima ed co a iance ma ix
equi alen o a andom poin ing e o when ackling wi h
con en ional sou ces. Besides, he highe he desi ed ecei ed
powe (and
so
he measu ed Eb/(No+Io)) he mo e p ecise he
es ima ion has o be in o de o p e en he desi ed signal om
being cancelled ou by he beam o me
[I].
Since accu acy is in
his case limi ed by he in e e ence
o
he a ic channel, a
high Eb/(No+Io) a ios he sys em can no a oid supp essing
he desi ed signal ins ead o enhancing i .
A ay
Fac o ,
Eblla=
WE,
EbiNo=
3MB
0
-5
-10
-15
--20
D
3
-25
e
-
-30
-35
-40
-45
-50
-100
-80
-60
-40
-20
0
20
40
60
80 100
Azimulh (deg)
Figu e
5.
Deg ada ion o he a ay esponse
due
o he
p esence
o
he
a ic
channel. Solid and
dash-do ed
line:
spa ial
esponse
o
he global beam o me . Do ed line: spa ial
esponse
o
he eigen ec o co esponding
o
he
maximum
eigen alue
o
he
desi ed signal co a iance
ma ix.
Desi ed
signal
DOA
-20
deg. In e e ing signal DOA
40
deg.
The consequences o his e ec on he a ay spa ial esponse
can be no iced in Figu e
5,
whe e he a ay ac o has been
ep esen ed
o
a
Pedes ian scena io in p esence
o
a high le el
o desi ed signal powe . In o de o ob ain mo e insigh in o he
beampa e n dis o ion e ec s, a low angula sp ead was chosen
(0.01
deg ees). I may ini ially seem ha when he aining
sequence is ansmi ed oge he wi h a a ic channel he
scheme can s ill es ima e he desi ed signal spa ial signa u e
(do ed line) wi h a ce ain deg ee o accu acy. Howe e he
global beam o me spa ial esponses show ha small e o s in
his es ima e esul in g ea dis o ion e ec s o he global
beampa e n, wha in u n b ings abou high deg ada ion o he
BER a he mobile s a ion.
870
Se e al possible solu ions o his dis o ion e ec a e cu en ly
being unde in es iga ion. They a e based on semi-blind
es ima ion echniques and basically seek o ake in o accoun
no only he aining sequence bu also o he unknown
in e e ing symbols embedded in he modula ed da a s eam
[4].
The o mula ion o hese algo i hms is no epo ed he e o lack
o space, al hough we do include p elimina y esul s o
demons a e hei po en ial.
In
pa icula , Figu e 6 shows he
ou pu SINR o he beam o me as
a
unc ion o he inpu powe
le el (wi h espec o he backg ound noise) in
an
scena io wi h
wo
HBR
use s ansmi ing wi h SF=8.
As
he powe o he
HBR
use s inc eases beyond
10
dB, p ope ou pu SINR alues
can
no
longe be sus ained. Ne e heless, his p ocli i y is
success ully o e come by means o he applica ion o
a
semi-
blind echnique based
on
a Condi ioned
ML
c i e ion. The
in e es ed eade is e e ed o
[4]
o u he de ails o he
algo i hm
as
well as mo e ex ensi e pe o mance simula ion
esul s.
Ou pu
SINR
s
Inpu
SNR
Semi-blind
CML
g
a
-10
-20
-20
_--------
-
J’
-10 -5
0
5
10
15
20
25
30
Inpu
SNR (dB)
Figu e
6.
Oiu pu SINR e sus Inpu SNR in a scena io wi h
wo HBR use s ansmi ing wi h SF=8 and he same powe .
Vehicula
115
in e e e s, Eb/No=PO dB
10”
10
’
I
I
cc
m
p
102
g
-
In
addi ion o lhe wo k p esen ed he e, link-le el simula ions
o
downlink
a ay-p ocessing algo i hms o he
FDD
mode o
UTRA
ha e
also
been pe o med (see
[5]
o de ails). Figu e
7
p esen s pe o mance cu es o wo di e en beam o ming
algo i hms:
a
poin ing scheme (DPA) and
a
null-s ee ing
scheme (DBNS). The DPA app oach seeks o gene a e
a
maximum may esponse owa ds he di ec ion o a i al o he
desi ed use whe eas he DBNS deploymen is pa icula ly
in ended o maximize he SINR a he mobile s a ion inpu .
Su p isingly, i can be obse ed ha he DPA algo i hm
ou pe o ms he DBNS scheme o alues o he ins an aneous
Ebb0 abo e 5-8
dB.
Once again, his beha io is basically
mo i a ed by a poo es ima ion o he desi ed signal spa ial
signa u e.
As
al eady shown, his es ima ion is p ecise enough
o p ope ly poin a he desi ed use , bu no
so
eliable o a oid
he desi ed signal supp ession when
a
maximum SINR s a egy
is adop ed.
6.
CONCLUSIONS
This pape has p esen ed some link-le el simula ion esul s o
he uplink and downlink o he cu en UTRA-FDD s anda d
de ini ion. Resul s show ha applica ion o classical ime-
e e ence beam o ming echniques encoun e s se e e
pe o mance p oblems when ope a ing a high inpu SNR
le els. A beampa e n dis o ion e ec , p incipally induced by
he mul iplexed a ic channel, has been shown o be he
ul ima e esponsible o he pe o mance deg ada ion. Finally,
semi-blind echniques a e pu o wa d
as
alid a chi ec u es o
ake in o accoun he p esence o he au o-in e e ing channel.
Pe o mance esul s o hese echniques will be u he
add essed in [4].
7.
REFERENCES
[I]
Comp on R. T., “Poin ing Accu acy and Dynamic Range in a
s ee ed bedm adap i e a ay”, IEEE T ans. on AES, ol.
AES-16,
121
Hdmlllinen
S.,
Slanina P., Ha man M., Lappe ellinen A., Holma
H.,
Salonaho
O.,
“A
No el In e ace be ween Link and Sys em
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599-604,
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Lagunas M.A., Pi ez A. and Vidal
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3
1”
Asiloma Con e ence on Signals, Sys ems and Compu e s, Paci ic
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Mes e
X.,
Fonollosa J. R., An 6n C., “Adap i e Beam o ming o
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in
he FDD mode o
UTRA”,
submi ed o he IEEE
Vehicula Technology Con e ence, 1999-Fal1, Ams e dam, The
Ne he lands.
[SI
Mes e
X.,
Fonollosa J.R, “Pe o mance E alua ion o UTRA-
FDD’,
P oc. FRAMES Wo kshop, Del (The Ne he lands),
Janua y
1999.
[6]
Nikula E., “Ai In e ace Speci ica ion, Laye
1,
D a ”,
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ACO~~/NOK/PTO/DS/R/~I~/~J~.
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[7]
Pede sen
K.I.,
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B.H.,
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he Tempo al and Azimu hal Dispe sion seen a he Base S a ion in
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[SI
Pipon E.P., Che alie P., Villa P., Mono J.J, “Join Spa ial and
Tempo al Equaliza ion o channels wi h
IS1
and CCI- Theo e ical
and Expe imen al esul s
o
a base s a ion ecep ion”, P oc. IEEE
Signal P ocessing Wo kshop on Signal P ocessing Ad ances in
191
“Submission o P oposed Radio T ansmission Technologies: he
ETSI UMTS Te es ial Radio Access (UTRA) ITU-R
R’M
Candida e Submission”,
ETSI
SMG2. Da e o submission:
29/1/1998. A ailable a he ITU
WWW
h p://www.i u.ch/im /
1976, pp. 280-287.
Wi eless
Communica ions, Pa is,
F ance,
Ap il 1997, pp.309-3
12.
87
1