RIS系统性能的进一步评估-英

Further

Evaluationof

RISSystemPerformanceYifei

Yuan,

Ph.DDec5,20230RISvs.Network-Controlled

Repeater

(NCR)•

Normally

onlyreflecting

incoming

signalwithoutpower

amplification•

RFof

control

link

can

be

independentof

data

link•

Backhaullink

and

accesslink

tightlycoupled,naturalfull-duplex•

Alargenumberofelementson

RIS

panel•

Can

beusedfor

coverage

enhancements,capacity

improvements,etc.RISrelayControl

linkControl

unitDLreflectedArray

ofreflectorsULreflectedBaseMobileterminalstationSharing

RFNetwork-controlled

repeater(NCR)•

With

power

amplification,

noisealsoamplified•

RFof

control

link

andbackhaul

link

sharecommon

RF•

Two

setsof

R

F,

each

for

backhaullink

and

accesslink,respectively,

to

achievefull-duplex•

Notmany

antennaelementson

NCR•

Mainly

usedfor

filling

coverage

holesControl

linkMobilefunctioninNCRForwarding

unitinNCRAccess

linkBackhaul

linkBasestationMobileterminalInband:sharing

RF1PerformanceComparisonatLow

FrequencyNCR

vs.RIS:in

low

frequency,

NCR

hashigher

powergaincompared

to

RIS,

but

withworse

SINR

due

tointerference

amplificationNCR

amplifies

signal,

interference

&noise

with

fixed

gain•

RSRP(reference

signalreceived

power)：NCR-UE

RSRP

=NCRAFGain+BTS-NCR

RSRP-NCR-UE

CouplinglosstotalRSRP=

BTS-UE

RSRP+NCR-UE

RSRP•

SINR（linear）：SINR

=total

RSRP/(UEreceived

noise+direct

linkinterference

+neighbor

BTS-neighborRepeater-UEinterference+neighbour

BTS-service

Repeater-UEamplifiedinterference)whereNCRAFGainadjustable,

but

NCRAFGain+BTS-NCR

RSRP

+BTS-NCRnoise+neighbor

BTS-Repeater

RSRP

interferenceRSRPSINR-

linear

≤

Relay

Tx

PowerAvg.

gain

in

RSRPAvg.

gain

in

SINRPercentage

of

repeaterpower

exceeding

maxSystem

level

simulation

parameters:•

UEatcell

edge,4NCR/RIS

persector•

#elements

perRIS

panel:40*40•

#elements

perNCR:

4*8，AF

Gain30/40dB•

Frequency:2.6GHzRepeater

FullPower24.6dB21.4dB15.1dB7.4dB4.37

dB4.57dB4.34dB7.08dBRepeater

AF

Gain40dBRepeater

AF

Gain30dBRIS

40*40,

2-bitquantization≈45%≈9%2PerformanceComparisonatHigh

FrequencyNCR

v.s.

RIS:

inhigh

frequency

band,

RIScangenerate

more

accurate

beamscompared

to

NCRBothNCRand

RISperform

beamforming

inhighfrequency•

NCRbeamsweeping•

RISUE-specificbeamformingSINRRSRPSystem

level

simulation

parameters:•

UE

atcelledge,4NCR/RIS

persector•

#elements

perRIS

panel:40*40•

#elementsperNCR:4*8，AFGain30/40dB•

Frequency:26

GHzPerformance

gap

between

RIS

and

NCR

is

smaller

in

high

frequency

than

lowfrequency

bands,dueto

thesmallerinterference

via

beamforming

atNCR3Difference

in

Beamforming

Approach

between

RIS

andNCRBeamdesignBS:sweeping.

NCR:beamsweeping.

RIS:

UE-specificbeamforming•

In

high-frequency,

BS

performs

beamsweeping.•

Strength

of

RIScascadedlink

comparable

todirect

link•

Strength

of

NCRcascadedlink

muchstronger

than

directlinkOptimal

chainwithout

RIS/dBmOptimal

chain

withRIS/dBmRelativestrength/dB-70.22-94.56-81.62-94.96-103.39-75.014.79-7.2311.25-22.64-21.20-87.32-92.87-72.32-82.18Optimal

chainwithout

NCR/dBm-103.60Optimal

chain

withNCR/dBmRelativestrength/dB-16.92-86.67-57.99-46.82-82.88-78.78NCR/RIS-94.04-36.04-54.10-14.63-14.121UE-100.92BTS2-97.52-92.91Proposal:

Inlow

frequency,