LTE Measurement: How to test a device

LTE, UMTS Long Term Evolution

LTE measurements – from RF to
application testing
Reiner Stuhlfauth
Reiner.Stuhlfauth@rohde-schwarz.com

Training Centre
Rohde & Schwarz, Germany
Subject to change – Data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG. Trade names are trademarks
of the owners.
 2011 ROHDE & SCHWARZ GmbH & Co. KG
Test & Measurement Division
- Training Center -
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ROHDE & SCHWARZ GmbH reserves the copy right to all of any part of these course notes.
Permission to produce, publish or copy sections or pages of these notes or to translate them must first
be obtained in writing from
ROHDE & SCHWARZ GmbH & Co. KG, Training Center, Mühldorfstr. 15, 81671 Munich, Germany

Mobile Communications: Fields for testing

l RF testing for mobile stations and user equipment
l RF testing for base stations
l Drive test solutions and verification of network
planning
l Protocol testing, signaling behaviour
l Testing of data end to end applications
l Audio and video quality testing
l Spectrum and EMC testing

November 2012 | LTE measurements| 2

Test Architecture RF-/L3-/IP Application-Test


LTE: EPS Bearer

E-UTRAN EPC Internet

UE eNB S-GW P-GW Peer
Entity

End-to-end Service

EPS Bearer External Bearer

Radio Bearer S1 Bearer S5/S8 Bearer

Radio S1 S5/S8 Gi


Mobile Radio Testing
Adjust the downlink Generate downlink
signal to how uplink is Perform
signal and send control
received RF measurements on
commands
received uplink

Core network

A mobile radio tester emulates a
base station


Mobile Radio Testing
Generate downlink Generate downlink
signal and send signal
signaling information No signaling Control PC

Signaling testing Non-Signaling testing


LTE measurements
general aspects


LTE RF Testing Aspects
UE requirements according to 3GPP TS 36.521
Power Transmit signal quality
 Maximum output power Frequency error
 Maximum power reduction Modulation quality, EVM
 Additional Maximum Power Carrier Leakage
Reduction In-Band Emission for non allocated RB
 Minimum output power
EVM equalizer spectrum flatness
 Configured Output Power
Output RF spectrum emissions
 Power Control
 Occupied bandwidth
 Absolution Power Control
 Out of band emissions
 Relative Power Control
 Aggregate Power Control  Spectrum emisssion mask

 ON/OFF Power time mask  Additional Spectrum emission mask
 Adjacent Channel Leakage Ratio
36.521: User Equipment (UE) radio
transmission and reception Transmit Intermodulation


UE requirements according to 3GPP, cont.
Receiver characteristics:
 Reference sensitivity level
 Maximum input level
 Adjacent channel selectivity
 Blocking characteristics
 In-band Blocking
 Out of band Blocking
 Narrow Band Blocking
 Spurious response
 Intermodulation characteristics
 Spurious emissions

Performance


BS requirements according to 3GPP

l Transmitter Characteristics
l Base station output power
l Frequency error
l Output power dynamics
l Transmit ON/OFF power
l Output RF spectrum emissions (Occupied bandwidth, Out of band
emission, BS Spectrum emission mask, ACLR, Spurious emission,
Co-existence scenarios,…)
l Transmit intermodulation
l Modulation quality TR 36.804: Base Station (BS) radio
transmission and reception


BS requirements according to 3GPP, cont.

l Receiver Characteristics
l Reference sensitivity level
l Dynamic range
l Adjacent Channel Selectivity (ACS)
l Blocking characteristics
l Intermodulation characteristics
l Spurious emissions
l Performance


LTE RF Measurements – regional requirements

l Regional / band-specific requirements exist (e.g. spurious emissions)
l Since UEs roam implementation has to be dynamic

 Concept of network signaled RF requirements has been introduced with
LTE.
- Network signaled value: NS_01 … NS_32
- transmitted as IE AdditionalSpectrumEmission in SIB2


LTE bands and channel bandwidth
E-UTRA band / channel bandwidth

E-UTRA Band
1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
1 Yes Yes Yes Yes

2 Yes Yes Yes Yes Yes[1] Yes[1]

3 Yes Yes Yes Yes Yes[1] Yes[1]

4 Yes Yes Yes Yes Yes Yes

5 Yes Yes Yes Yes[1]

6 Yes Yes[1]



9 Yes Yes Yes[1] Yes[1]

10 Yes Yes Yes Yes

11 Yes Yes[1]

12 Yes Yes Yes[1] Yes[1]

13

14
Yes[1]

Yes[1]
Yes[1]

Yes[1]
Not every channel
...

17 Yes[1] Yes[1]
bandwidth for
... every band!
33 Yes Yes Yes Yes

34 Yes Yes Yes



37 Yes Yes Yes Yes

38 Yes Yes Yes Yes

39 Yes Yes Yes Yes

40 Yes Yes Yes Yes

NOTE 1: bandwidth for which a relaxation of the specified UE receiver sensitivity requirement (Clause 7.3) is allowed.


Tests performed at “low, mid and highest frequency”
Nominal frequency
RF power

described by EARFCN
(E-UTRA Absolute lowest EARFCN possible
Radio Frequency
Channel Number)
and 1 RB at position 0

Frequency = whole LTE band
RF power

mid EARFCN
and 1 RB at position 0

Frequency
RF power

Highest EARFCN
and 1 RB at max position

Frequency


Test Environment – Test System Uncertainty
36.101 / 36.508
• Temperature/Humidity
-normal conditions +15C to +35C, relative humidity 25 % to 75 %
-extreme conditions -10C to +55C (IEC 68-2-1/68-2-2)

• Voltage

• Vibration

Acceptable Test System Uncertainty (Test Tolerance, TT) defined for each test individually
in 36.521 Annex F (will be ignored further on for the sake of simplicity)

Test Minimum Requirement in TS Test Test Requirement in TS 36.521-
36.101 Tolerance 1
(TT)
6.2.2. UE Power class 1: [FFS] 0.7 dB Formula:
Maximum Output Power class 2: [FFS] 0.7 dB Upper limit + TT, Lower limit - TT
Power Power class 3: 23dBm ±2 dB 0.7 dB Power class 1: [FFS]
Power class 4: [FFS] 0.7 dB Power class 2: [FFS]
Power class 3: 23dBm ±2.7 dB
Power class 4: [FFS]


LTE RF measurements
on base stations


OFDM risk: Degradation

Channel (ideal)

sl  n  rl  n 

1
TMC

Samples
f
f0 f1 f2 f3 f0 f1 f2 f3

OFDM risk: Degradation due to Frequency Offset

Channel
e j 2fn

sl  n  rl  n 

f

Samples
f
f0 f1 f2 f3 f0 f1 f2 f3


OFDM risk: Degradation due to Clock Offset

Channel

sl  n   rl  n 

f  k

Samples
f
f0 f1 f2 f3 f0 f1 f2 f3


Subcarrier zero handling
Subcarrier 0 or DC subcarrier
causes problems in DAC for
direct receiver strategies, DC offset!

Downlink:
f-1 f+1
1
j 2kf t  N CP ,l Ts 
N RB Nsc / 2
DL RB

sl( p ) t    ak (p)) ,l  e
(
  ak( (p)) ,l  e j 2kf t  NCP ,lTs  DC subcarrier,

k   N RB N sc / 2
DL RB
 k 1 suppressed
1/TSYMBOL=15kHz
Uplink:
N RB Nsc / 2 1
UL RB

j 2 k 1 2 f t  N CP ,l Ts 
sl t    a k (  ) ,l  e

k   N RB N sc / 2
UL RB
 f-1 f0 f1
f
½ subcarrier
DC subcarrier
offset

LTE: DC subcarrier usage

DC subcarrier or subcarrier 0 is not used in downlink!


DC offset – possible reasons
DC offset originated by mixer:

fBB=fRx-fLO
fRX=fLO+fBB+fLO_ɛ 1st mixer
fLO –fLO_ɛ=DC fBB + DC

Non-linearities of
fLO_ɛ fLO Amplifier also cause
DC in the signal

PLL

Idea: set PLL to frequency fLO to get frequency of baseband
as fBB = fRX – fLO
But: if synthesizer has leakage: fLO_ɛ will spread into the input:
At the output we get direct current, DC!

Base station test models
Parameter 1.4 MHz 3 MHz 5 MHz 10 MHz 15 MHz 20 MHz
Reference, Synchronisation Signals
RS boosting, PB = EB/EA 1 1 1 1 1 1
Synchronisation signal EPRE / ERS [dB] 0.000 0.000 0.000 0.000 0.000 0.000
Reserved EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf
PBCH
PBCH EPRE / ERS [dB] 0.000 0.000 0.000 0.000 0.000 0.000
Reserved EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf
PCFICH
# of symbols used for control channels 2 1 1 1 1 1
PCFICH EPRE / ERS [dB] 3.222 0 0 0 0 0
PHICH
# of PHICH groups 1 1 1 2 2 3
# of PHICH per group 2 2 2 2 2 2
PHICH BPSK symbol power / ERS [dB] -3.010 -3.010 -3.010 -3.010 -3.010 -3.010
PHICH group EPRE / ERS [dB] 0 0 0 0 0 0
PDCCH
# of available REGs 23 23 43 90 140 187
# of PDCCH 2 2 2 5 7 10
# of CCEs per PDCCH 1 1 2 2 2 2 TS 36.141
# of REGs per CCE 9 9 9 9 9 9
# of REGs allocated to PDCCH 18 18 36 90 126 180
Defines several
# of <NIL> REGs added for padding 5 5 7 0 14 7 Test models
PDCCH REG EPRE / ERS [dB] 0.792 2.290 1.880 1.065 1.488 1.195
<NIL> REG EPRE / ERS [dB] -inf -inf -inf -inf -inf -inf For base station
PDSCH
# of QPSK PDSCH PRBs which are boosted 6 15 25 50 75 100
e.g. E-TM1.1
PRB PA = EA/ERS [dB] 0 0 0 0 0 0
# of QPSK PDSCH PRBs which are de-boosted 0 0 0 0 0 0

PRB PA = EA/ERS [dB] n.a. n.a. n.a. n.a. n.a. n.a.


Base station unwanted emissions
Spurious emissions
ACLR
•Adjacent channel leakage
•Operating band unwanted emissions
Channel
Spurious domain ΔfOOB bandwidth ΔfOOB Spurious domain

RB

E-UTRA Band

Worst case:
Ressource Blocks allocated
at channel edge

Adjacent Channel Leakage Ratio - eNB
E-UTRA transmitted BS adjacent channel Assumed Filter on the ACLR
signal channel centre adjacent adjacent lim
bandwidth frequency offset channel channel it
BWChannel [MHz] below the first carrier frequency and
or above the last (informative) corresponding
carrier centre filter bandwidth
frequency
transmitted
1.4, 3.0, 5, 10, 15, 20 BWChannel E-UTRA of same Square (BWConfig) 45 dB
BW

2 x BWChannel E-UTRA of same Square (BWConfig) 45 dB
BW

BWChannel /2 + 2.5 3.84 Mcps UTRA RRC (3.84 Mcps) 45 dB
MHz
BWChannel /2 + 7.5 3.84 Mcps UTRA RRC (3.84 Mcps) 45 dB
MHz
NOTE 1: BWChannel and BWConfig are the channel bandwidth and transmission bandwidth configuration
of the E-UTRA transmitted signal on the assigned channel frequency. Large bandwidth
NOTE 2: The RRC filter shall be equivalent to the transmit pulse shape filter defined in TS 25.104 [6],
with a chip rate as defined in this table.
Limit is either -13 / -15dBm absolute or as above

Adjacent channel leakage power ratio


ACLR measurement * RBW 10 kHz
VBW 30 kHz
Ref 0 dBm Att 25 dB SWT 250 ms

0
*
A
-10

1 AP
VIEW
-20

2 AP
VIEW
-30

3 AP
CLRWR
-40

-50 EXT
UTRAACLR1 UTRAACLR2
= 33 dB = 36 dB UTRAACLR2bis
3DB
= 43 dB
-60

-70

-80

-90 Additional requirement for
E-UTRA frequency band I,
-100 signaled by network to the UE
Center 1.947 GHz 2.5 MHz/ Span 25 MHz

fUTRA, ACLR2 fUTRA, ACLR1 fCarrier

Date: 21.AUG.2008 15:51:00

Operating band unwanted emissions
Narrow bandwidth
Frequency offset Frequency offset of Minimum requirement Measurem
of measurement measurement filter centre ent
filter -3dB point, f frequency, f_offset bandwidth
(Note 1)

0 MHz  f < 5 0.05 MHz  f_offset < 5.05 100 kHz
7  f _ offset 
MHz MHz  7dBm     0.05 dB
5  MHz 
5 MHz  f < 5.05 MHz  f_offset < -14 dBm 100 kHz
min(10 MHz, min(10.05 MHz,
fmax) f_offsetmax)

10 MHz  f  10.05 MHz  f_offset < -16 dBm (Note 5) 100 kHz
fmax f_offsetmax

TS 36.104 defines several limits: depending on
Channel bandwidth, additional regional limits and node B
limits category A or B for ITU defined regions
=> Several test setups are possible!

Operating band unwanted emissions


Unwanted emissions – spurious emission
The transmitter spurious emission limits apply from 9 kHz to 12.75 GHz,
excluding the frequency range from 10 MHz below the lowest frequency of the downlink
operating band up to 10 MHz above the highest frequency of the downlink operating band

Frequency range Maximum level Measurement Note
Bandwidth

9kHz - 150kHz 1 kHz Note 1

150kHz - 30MHz 10 kHz Note 1

-13 dBm
30MHz - 1GHz 100 kHz Note 1

1GHz – 12.75 GHz 1 MHz Note 2

NOTE 1: Bandwidth as in ITU-R SM.329 [5] , s4.1
NOTE 2: Bandwidth as in ITU-R SM.329 [5] , s4.1. Upper frequency as in ITU-R SM.329 [5] , s2.5 table 1

Spurious emission limits, Category A


Spurious emissions – operating band excluded


Base station maximum power
In normal conditions, the base station maximum output power
shall remain within +2 dB and -2 dB of the rated output power
declared by the manufacturer.
Towards
External External antenna connector
PA device 
BS e.g.
cabinet TX filter
(if any) (if any)

Test port A Test port B

Normal port for Port to be used for
measurements measurements in case
external equipment is
used

LTE – DVB interference scenarios
Adjacent channel leakage of
Basestation x into DTT channel N
is point of interest

For a BS declared to support Band 20 and to operate in geographic areas within the CEPT in
which frequencies are allocated to broadcasting (DTT) service, the manufacturer shall additionally
declare the following quantities associated with the applicable test conditions of
Table 6.6.3.5.3-4 and information in annex G of [TS 36.104] :
PEM,N Declared emission level for channel N
P10MHz Maximum output Power in 10 MHz


Base station receiver test
Example: Rx test, moving condition

70% of required throughput of FRC, Fixed Reference Channel


Base station receiver test – HARQ multiplexing

UE sends PUSCH with alternating data
and data with multiplexed ACK


Base station test – power dynamics

Synchronisation
time/frequency

BS under
Test FFT
2048
Per Symbol
100 subcarrier Detection /
RF- CP- RBs, Ampl. decoding
correc- remov 1200 /Phase
tion sub correction
carr

EVM
Resource element Tx RETP
power: Distinguish:
•OFDM symbol
•Reference symbol


Downlink Power
Reference Signal:
Cell-specific PDCCH power
PDSCH power to RS, where NO reference
referenceSignalPower depending
signals are present, is UE specific and
(-60…+50dBm), on ρB/ρA
signaled by higher layers as PA.
signaled in SIB Type 2
For PDSCH power in same
[Power] symbol as reference signal an
additional cell specific offset
is applied, that is signaled by
-50.00 dBm higher layers as PB.

PA = -4.77 dB

2011 © Rohde&Schwarz
-54.77 dBm

PB = 3 (-3.98 dB)

-58.75 dBm

0 1 2 3 4 5 6 7 8 9 10 11 12 13 [Time]
OFDM symbols

RS EPRE = Reference Signal Reference signal power = linear average of all Ref.
Energy per Resource Element Symbols over whole channel bandwidth

EPRE PDSCH   A / B  EPRE RS B  PB   A  A  PA (with some exeptions for MIMO)


Base station test – output power dynamics
Measure avg OFDM
symbol power +
Compare active and
non-active case

Ref. Symbol, always on

OFDM Symbol not active!

OFDM Symbol active!

PDSCH
# of 64QAM PDSCH PRBs within a slot for which
EVM is measured
1 1 1 1 1 1 Test model:
PRB PA = EA/ERS [dB] 0 0 0 0 0 0 E-TM3.1
# of PDSCH PRBs which are not allocated 5 14 24 49 74 99
All RB allocated

Test model: PDSCH
# of 64QAM PDSCH PRBs within a slot for which EVM 6 15 25 50 75 100
E-TM2 is measured
Only 1 RB allocated


DL Modulation quality: Constellation diagram
LTE downlink: several channels can be seen (example):

PDSCH with
16 QAM
PDCCH +
PBCH with
QPSK
S-SCH with
BPSK
CAZAC
Sequences,
Reference signals


LTE RF measurements
on user equipment UEs


LTE Transmitter Measurements
1 Transmit power
1.1 UE Maximum Output Power
1.2 Maximum Power Reduction (MPR)
1.3 Additional Maximum Power Reduction (A-MPR)
1.4 Configured UE transmitted Output Power
2 Output Power Dynamics
2.1 Minimum Output Power
2.2 Transmit OFF power
2.3 ON/OFF time mask
2.3.1 General ON/OFF time mask
2.3.2 PRACH time mask
2.3.3 SRS time mask
2.4 Power Control
2.4.1 Power Control Absolute power tolerance
2.4.2 Power Control Relative power tolerance
2.4.3 Aggregate power control tolerance
3 Transmit signal quality
3.1 Frequency Error
3.2 Transmit modulation
3.2.1 Error Vector Magnitude (EVM)
3.2.2 Carrier leakage
3.2.3 In-band emissions for non allocated RB
3.2.4 EVM equalizer spectrum flatness
4 Output RF spectrum emissions
4.1 Occupied bandwidth
4.2 Out of band emission
4.2.1 Spectrum Emission Mask
4.2.2 Additional Spectrum Emission Mask
4.2.3 Adjacent Channel Leakage power Ratio
4.3 Spurious emissions
4.3.1 Transmitter Spurious emissions
4.3.2 Spurious emission band UE co-existence
4.3.3 Additional spurious emissions
5 Transmit intermodulation


UE Signal quality – symbolic structure of
mobile radio tester MRT
Test equipment
Rx
TxRx EVM

…
…
…
equalizer IDFT meas.
DUT RF
correction FFT
Inband-

…
…
…
emmissions

l Carrier Frequency error
l EVM (Error Vector Magnitude)
l Origin offset + IQ offset
l Unwanted emissions, falling into non allocated resource blocks.
l Inband transmission
l Spectrum flatness


UL Power Control: Overview
UL-Power Control is a
combination of:

l Open-loop:
UE estimates the DL-Path-
loss and compensates it
for the UL

l Closed-loop:
in addition, the eNB
controls directly the UL-
Power through power-
control commands
transmitted on the DL


PUSCH power control
l Power level [dBm] of PUSCH is calculated every subframe i based on the following
formula out of TS 36.213
MPR

Maximum allowed UE power
in this particular cell, Combination of cell- and UE-specific PUSCH transport
but at maximum +23 dBm1) components configured by L3 format

Number of allocated Cell-specific Downlink Power control
resource blocks (RB) parameter path loss adjustment derived
Transmit power for PUSCH configured by L3 estimate from TPC command
in subframe i in dBm received in subframe (i-4)

Bandwidth factor Basic open-loop starting point Dynamic offset (closed loop)
1) +23 dBm is maximum allowed power in LTE according to TS 36.101, corresponding to power class 3bis in WCDMA


Pcmax definition „upper“ tolerance
„lower“ tolerance
„corrected“ UE power

PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)

PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}

Max. power permitted Max. power
in cell, permitted in cell
considering bandwidth
confinement Max. power for
UE
Max. power for UE,
considering maximum
power reduction


Pcmax definition
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H),

lPCMAX_L = min{PEMAX_L , PUMAX },

l PEMAX_L is the maximum allowed power for this particular radio cell
configured by higher layers and corresponds to P-MAX information
element (IE) provided in SIB Type1
l
l PEMAX_L is reduced by 1.5 dB when the transmission BW is confined within
FUL_low and FUL_low+4 MHz or FUL_high – 4 MHz and FUL_high,

PPowerClass +
2dB
23dBm
PPowerClass - 2dB
-1.5dB -1.5dB

FUL_low FUL_high- 4MHz FUL_high

Pcmax definition
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H),

PCMAX_L = min{PEMAX_L , PUMAX },

l PUMAX corresponds to maximum power (depending on power class,
taking into account Maximum Power Reduction MPR and additional
A-MPR UE may decide to
reduce power

UE power class Network may signal
= 23dBm ±2 dB bandwidth restriction
NS_0x


UE Maximum Power Reduction
UE transmits
at maximum power, maximum allowed
TX power reduction is given as

Modulation Channel bandwidth / Transmission bandwidth configuration MPR (dB)
[RB]
1.4 3.0 5 10 15 20
MHz MHz MHz MHz MHz MHz
QPSK >5 >4 >8 > 12 > 16 > 18 ≤1
16 QAM ≤5 ≤4 ≤8 ≤ 12 ≤ 16 ≤ 18 ≤1
16 QAM Full >5 >4 >8 > 12 > 16 > 18 ≤2

Higher order modulation schemes require
more dynamic -> UE will slightly repeal its
confinement for maximum power

UE Additional Maximum Power Reduction A-MPR
Additional maximum Network Requirements E-UTRA Band Channel Resource A-MPR (dB)
Signaling (sub-clause) Bandwidth Blocks
power reduction value (MHz)
requirements can be NS_01 NA NA NA NA NA
signaled by the 6.6.2.2.3.1 2,4,35,36 3 >5 ≤1
network as NS value 6.6.2.2.3.1 2,4,10,35,36 5 >6 ≤1
in SIB2 NS_03 6.6.2.2.3.1 2,4,10,35,36 10 >6 ≤1
(IE AdditionalSpectrumEmission) 6.6.2.2.3.1 2,4,10,35,36 15 >8 ≤1
6.6.2.2.3.1 2,4,10,35,36 20 >10 ≤1
NS_04 6.6.2.2.3.2 TBD TBD TBD TBD
NS_05 6.6.3.3.3.1 1 10,15,20 ≥ 50 for QPSK ≤1

NS_06 6.6.2.2.3.3 12, 13, 14, 17 1.4, 3, 5, 10 n/a n/a

6.6.2.2.3.3 Table
NS_07 13 10 Table 6.2.4.3-2
6.6.3.3.3.2 6.2.4.3-2
> 29 ≤1
NS_08 6.6.3.3.3.3 19 10, 15 > 39 ≤2
> 44 ≤3
[NS_09] 6.6.3.3.3.4 21 TBD TBD TBD

..

NS_32 - - - - -


PUSCH power control
Transmit output power ( PUMAX), cont’d.
3GPP Band 13
746 756 777 787

DL UL

Network Requiremen Channel
E-UTRA Resources A-MPR
Signalling ts bandwidth
Band Blocks (dB)
Value (sub-clause) (MHz)
… … … … … …
Table Table
6.6.2.2.3
NS_07 13 10 6.2.4 6.2.4
6.6.3.3.2
-2 -2
Indicates the lowest RB
… … … … … …
index of transmitted
Region A Region B Region C
resource blocks

RBStart 0 – 12 13 – 18 19 – 42 43 – 49
Defines the length of a
contiguous RB allocation LCRB [RBs] 6–8 1 – 5 to 9 – 50 ≥8 ≥18 ≤2

A-MPR [dB] 8 12 12 6 3

l In case of EUTRA Band 13 depending on RB allocation as well as
number of contiguously allocated RB different A-MPR needs to be
considered. November 2012 | LTE measurements| 50

Pcmax definition – tolerance values

PCMAx Tolerance
(dBm) T(PCMAX) (dB)
21 ≤ PCMAX ≤ 23 2.0
Tolerance is 20 ≤ PCMAX < 21 2.5
depending on
19 ≤ PCMAX < 20 3.5
power levels
18 ≤ PCMAX < 19 4.0
13 ≤ PCMAX < 18 5.0
8 ≤ PCMAX < 13 6.0
-40 ≤ PCMAX < 8 7.0



PCMAX_H = min{PEMAX_H , PPowerClass },

l PEMAX_H is the maximum allowed power for this particular radio
cell configured by higher layers and corresponds to P-MAX
information element (IE) provided in SIB Type 1

UE power class
= 23dBm ±2 dB



PCMAX_H = min{PEMAX_H , PPowerClass },
l PPowerClass. There is just one power class specified for LTE,
corresponding to power class 3bis in WCDMA with +23 dBm ± 2dB,
MPR and A-MPR are not taken into account,

Class 1 Tolerance Class 2 Tolerance Class 3 Tolerance (dB) Class 4 Tolerance (dB)
EUTRA
(dB (dB) (dBm) (dB) (dBm (dBm)
band m) )

1 23 ±2
2 23 ±22
… 23 ±22
40 23 ±2


Pcmax value for power control - analogies


Maximum speed = 280 km/h
=PPowerClass

Under those conditions,
I shall drive more carefully!
Not going to the max seed!
=PEMAX_H =PEMAX_L =PUMAX -> speed reduction


LTE RF Testing: UE Maximum Power

UE transmits
with 23dBm ±2 dB

QPSK modulation is used. All channel bandwidths are
tested separately. Max power is for all band classes
Test is performed for varios uplink allocations


Resource Blocks number and maximum RF power
1 active resource block
(RB),
Nominal
RF power

band width One active resource block
10 MHz
= 50 RB’s
(RB) provides maximum
absolute RF power

Frequency
More RB’s in use will be at
RF power

lower RF power in order to
create same integrated
power
Frequency
RF power

Additionally, MPR (Max.
Power Reduction) and A-
MPR MPR are defined

Frequency


UE Maximum Output Power – Test Configuration
Initial Conditions
Test Environment as specified in TS 36.508 subclause 4.1 Normal, TL/VL, TL/VH, TH/VL, TH/VH Temperature/Voltage
Test Frequencies as specified in TS 36.508 subclause 4.3.1 Low range, Mid range, High range high/low

Test Channel Bandwidths as specified in TS 36.508 subclause 4.3.1 Lowest, 5MHz, Highest
Test Parameters for Channel Bandwidths
Downlink Configuration Uplink Configuration
Ch BW N/A for Max UE output power testing Mod’n RB allocation
FDD TDD
1.4MHz QPSK 1 1
1.4MHz QPSK 5 5
3MHz QPSK 1 1
3MHz QPSK 4 4
5MHz QPSK 1 1
5MHz QPSK 8 8
10MHz QPSK 1 1
10MHz QPSK 12 12
15MHz QPSK 1 1
15MHz QPSK 16 16
20MHz QPSK 1 1
20MHz QPSK 18 18


UE maximum power
PPowerClass + 2dB

23dBm
PPowerClass - 2dB

maximum output FUL_high
FUL_low power for any
transmission bandwidth
within the channel bandwidth


UE maximum power – careful at band edge!
PPowerClass + 2dB

23dBm
PPowerClass - 2dB
-1.5dB -1.5dB

FUL_low FUL_high- 4MHz FUL_high
FUL_low+4MHz
For transmission bandwidths confined within FUL_low and FUL_low + 4 MHz or
FUL_high – 4 MHz and FUL_high, the maximum output power requirement is relaxed
by reducing the lower tolerance limit by 1.5 dB

UE maximum power - examples
Example 1: No maximum power reduction by higher layers


Max. power permitted in cell, Max. power for UE, Max. power permitted in Max. power for UE
considering bandwidth considering maximum power cell
confinement reduction

PEMAX_L = none PUMAX = power class 3 = +23 dBm T(PCMAX_L) = T(PCMAX_H)=2dB
PEMAX_H = none PPowerClass = power class 3 = +23 dBm
PPowerClass + 2dB 25dBm

23dBm

PPowerClass - 2dB 21dBm

FUL_low FUL_high


Example 2: max cell power = 0 dBm + band edge maximum power reduction



PEMAX_L = 0dBm -1.5 dB relaxation = -1.5dBm PEMAX_H = 0 dBm
PUMAX = power class 3 – band relaxation = +21.5 dBm PPowerClass = power class 3 = +23 dBm

PCMAX_L=-1.5dBm
PCMAX_H=0 dBm
T(PCMAX_L) = T(PCMAX_H)=7dB
PCMAX_H + 7dB +7dBm

0 dBm

PCMAX_L - 7dB -8.5dBm

FUL_low FUL_low+4MHz FUL_high


Example 3: Band 13 with NS_07 signalled ( = A-MPR). No Max Power restriction
16 QAM, 12 Resource blocks and RB start = 13. Bandwidth = 10 MHz
MPR = 1dB, A-MPR = 12 dB, no band edge relaxation
PCMAX_H = min{PEMAX_H, PPowerClass}
PCMAX_L = min{PEMAX_L, PUMAX }

PEMAX_L = none PEMAX_H = none
PUMAX = power class 3 – MPR – A.MPR = +10 dBm PPowerClass = power class 3 = +23 dBm

PCMAX_L=10 dBm T(PCMAX_L) = 6 dB PCMAX_H=23 dBm +25dBm
T(PCMAX_H)=2dB
PCMAX_H +2dB
23 dBm

PCMAX_L - 6dB 4 dBm

RB start = 13 12 Resource blocks FUL_high


Example 4: band edge power relaxation – no higher layer reduction signalled
QPSK, 15 RBs allocated, Band 2, RB allocated at band edge
MPR = 1dB, A-MPR = 1 dB, band edge relaxation of 1.5dB

PEMAX_L =none PEMAX_H = none
PUMAX = power class 3 – MPR-A-MPR-band relaxation PPowerClass = power class 3 = +23 dBm
= 23-1-1-1.5=+19.5 dBm
PCMAX_H= 23 dBm
PCMAX_L=19.5dBm PCMAX_H + 2dB +25 dBm
T(PCMAX_L) = 3.5 dB
T(PCMAX_H)=2dB
23 dBm
PCMAX_L – 2 dB
PCMAX_L – 3.5 dB
+16 dBm

FUL_low FUL_low+4MHz FUL_high


LTE RF Testing: UE Minimum Power

UE transmits
with -40dBm

All channel bandwidths are tested separately.
Minimum power is for all band classes < -39 dBm


LTE RF Testing: UE Off Power

The transmit OFF power is defined as the mean power in a duration of at least one
sub-frame (1ms) excluding any transient periods. The transmit OFF power shall not
exceed the values specified in table below

Channel bandwidth / Minimum output power / measurement bandwidth

1.4 3.0 5 10 15 20

Transmit OFF power -50 dBm

Measurement
1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz
bandwidth


Power Control Related test items

l Absolute Power Control Tolerance -- PUSCH open loop
power control

l Relative Power Control Tolerance – PUSCH relative power
control, including both power ramping and power change due
to Ressource block allocation change or TPC commands

l Aggregate Power Control – PUSCH and PUCCH power
control ability when RB changes every subframe


Absolute Power Control Tolerance
l The purpose of this test is to verify the UE transmitter’s
ability to set its initial output power to a specific value at the
start of a contiguous transmission or non-contiguous
transmission with a long transmission gap.


Power Control - Absolute Power Tolerance
l …. ability to set initial output power to a specific value at the start of a
contiguous transmission or non-contiguous transmission with a long
transmission gap (>20ms).

l Set p0-NominalPUSCH to -105 (test point 1) and -93 (test point 2)

l Test requirement example for test point 1:

Channel bandwidth / expected output power (dBm)
1.4 3.0 5 10 15 20
Expected Measured
-14.8 ± -10.8 ± -8.6 ± -5.6 ± -3.9 ± -2.6 ±
power Normal
10.0 10.0 10.0 10.0 10.0 10.0
conditions
Expected Measured
-14.8 ± -10.8 ± -8.6 ± -5.6 ± -3.9 ± -2.6 ±
power Extreme
13.0 13.0 13.0 13.0 13.0 13.0
conditions


Configured UE transmitted Output Power

IE P-Max (SIB1) = PEMAX

To verify that UE follows rules sent via
system information, SIB
Test: set P-Max to -10, 10 and 15 dBm, measure PCMAX

Channel bandwidth / maximum output power
1.4 3.0 5 10 15 20
PCMAX test point 1 -10 dBm ± 7.7
PCMAX test point 2 10 dBm ± 6.7
PCMAX test point 3 15 dBm ± 5.7


LTE Power versus time
RB allocation
is main source for
power change

Not scheduled
Resource block

PPUSCH (i)  min{PMAX ,10 log10 (M PUSCH (i))  PO_PUSCH ( j )    PL   TF (TF (i))  f (i)}
Bandwidth allocation Given by higher layers TPC commands
or not used


Accumulative TPC commands

TPC Command Field Accumulated
In DCI format 0/3  PUSCH [dB]
0 -1
1 0
2 1
3 3

2
minimum
power in LTE


Absolute TPC commands
PPUSCH (i)  min{ PMAX ,10 log 10 ( M PUSCH (i))  PO_PUSCH ( j )    PL   TF (TF (i))  f (i)}

TPC Command Field Absolute  PUSCH [dB]
In DCI format 0/3 only DCI format 0
0 -4
1 -1
2 1
3 4

Pm
-1
-4


Relative Power Control
Power pattern B
Power pattern A

RB change

RB change

0 .. 9 sub-frame# 0 .. 9 sub-frame#
1 2 3 4 radio frame 1 2 3 4 radio frame

Power pattern C

l The purpose of this test is to verify
RB change the ability of the UE transmitter to set
its output power relatively to the
power in a target sub-frame, relatively
to the power of the most recently
transmitted reference sub-frame, if the
0 ..
1
9 sub-frame#
2 3 4 radio frame transmission gap between these sub-
frames is ≤ 20 ms.

Power Control – Relative Power Tolerance
l …. ability to set output power relative to the power in a target sub
frame, relative to the power of the most recently transmitted
reference sub-frame, if the transmission gap between these
sub-frames is ≤ 20 ms.


Power Control – Relative Power Tolerance
l Various power ramping patterns are defined

ramping down

alternating

ramping up


UE power measurements – relative power change
All combinations of
All combinations of PUSCH/PUCCH
Power step P
PUSCH and and SRS
(Up or down) PRACH [dB]
PUCCH transitions
[dB]
transitions [dB] between sub-
frames [dB]
ΔP < 2 ±2.5 (Note 3) ±3.0 ±2.5
2 ≤ ΔP < 3 ±3.0 ±4.0 ±3.0
3 ≤ ΔP < 4 ±3.5 ±5.0 ±3.5
4 ≤ ΔP ≤ 10 ±4.0 ±6.0 ±4.0
10 ≤ ΔP < 15 ±5.0 ±8.0 ±5.0
15 ≤ ΔP ±6.0 ±9.0 ±6.0
P

Power tolerance relative given by table

time


UE power measurements – relative power change
Power Power

FDD test patterns TDD test patterns
test for
each
bandwidth,
here 10MHz
0 1 9 sub-frame# 0 2 3 7 8 9 sub-frame#

Sub-test Uplink RB allocation TPC command Expected power
Power step size
step size
range (Up or PUSCH/
(Up or
down)
down)
ΔP [dB] ΔP [dB] [dB]
A Fixed = 25 Alternating TPC =
1 ΔP < 2 1 ± (1.7)
+/-1dB
B Alternating 10 and 18 TPC=0dB 2.55 2 ≤ ΔP < 3 2.55 ± (3.7)
C Alternating 10 and 24 TPC=0dB 3.80 3 ≤ ΔP < 4 3.80 ± (42.)
D Alternating 2 and 8 TPC=0dB 6.02 4 ≤ ΔP < 10 6.02 ± (4.7)
E Alternating 1 and 25 TPC=0dB 13.98 10 ≤ ΔP < 15 13.98 ± (5.7)
F Alternating 1 and 50 TPC=0dB 16.99 15 ≤ ΔP 16.99 ± (6.7)


UE aggregate power tolerance
Aggregate power control tolerance is the ability of a UE to maintain its power in
non-contiguous transmission within 21 ms in response to 0 dB TPC commands
TPC command UL channel Aggregate power tolerance within 21 ms

0 dB PUCCH ±2.5 dB

0 dB PUSCH ±3.5 dB

Note:
1. The UE transmission gap is 4 ms. TPC command is transmitted via PDCCH 4 subframes preceding
each PUCCH/PUSCH transmission.

Tolerated UE power
P deviation

UE power with
TPC = 0

Time = 21 milliseconds


Aggregate Power Control
l The purpose of this test is to verify the UE’s ability to
maintain its power level during a non-contiguous
transmission within 21 ms in response to 0 dB TPC
commands with respect to the first UE transmission, when
the power control parameters specified in TS 36.213 are
constant.
l Both PUSCH mode and PUCCH mode need to be tested
Power Power


0 5 0 5 0 3 8 3 8 3
sub-frame# sub-frame#


UE aggregate power tolerance

Power Power


0 5 0 5 0 3 8 3 8 3
sub-frame# sub-frame#

Test performed with scheduling gap of 4 subframes


UE power measurement – timing masks

Start Sub-frame End sub-frame

Start of ON power End of ON power

End of OFF power Start of OFF power
requirement requirement
* The OFF power requirements does not
apply for DTX and measurement gaps
20µs 20µs
Transient period Transient period

Timing definition OFF – ON commands

Timing definition ON – OFF commands


Power dynamics

PUSCH = OFF PUSCH = ON PUSCH = OFF time
Please note: scheduling cadence for power dynamics

General ON/OFF time mask
Measured subframe = 2
UL/DL Scheduling should be configured properly.
TDD Issues:
- Special Subframe
Configuration
- >off power before is
highter than off
power after
- <> tune down DL
power


PRACH time mask
PRACH

ON power requirement


20µs 20µs


PRACH Channel bandwidth / Output Power [dBm] / measurement
Measurement bandwidth
preamble
period (ms)
format 1.4 3.0 5 10 15 20
0 0.9031 MHz MHz MHz MHz MHz MHz
Transmit OFF
1 1.4844  -48.5 dBm
power
2 1.8031 Transmission OFF
3 2.2844 Measurement 1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz
bandwidth
4 0.1479
Expected PRACH
Transmission ON -1± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5 -1 ± 7.5
Measured power


UE power measurement – PRACH timing mask
PRACH preamble format Measurement period (ms)
0 0.9031
1 1.4844
2 1.8031
3 2.2844
4 0.1479

PRACH

ON power requirement


20µs 20µs



PRACH measurements

For PRACH
you have to
set a trigger Reminder:
PRACH is
CAZAC
sequence


PRACH measurement: constellation diagram

Reminder:
PRACH is
CAZAC
sequence


PRACH measurement: power dynamics


Sounding Reference Signal Time Mask


UE power measurement – SRS timing mask
SRS

SRS ON power
requirement
Single Sounding
Reference Symbol
End of OFF Start of OFF power
power requirement requirement

20µs 20µs


SRS SRS

Double Sounding SRS ON power SRS ON power
Reference Symbol requirement requirement

End of OFF Start of OFF power
power requirement requirement

20µs 20µs 20µs 20µs
Transient period *Transient period Transient period

* Transient period is only specifed in the case of frequency hopping or a power change between SRS symbols


UE power measurement – Subframe / slot boundary

N+1 Sub-frame
N0 Sub-frame N+2 Sub-frame
Sloti Sloti+1

Start of N+1 power End of N+1 power

20µs 20µs 20µs 20µs 20µs 20µs

Transient period Transient period Transient period

If intra-slot hopping is enabled

Periods where power changes may occur


Tx power aspects
RB power = Ressource Block Power, power of 1 RB
TX power = integrated power of all assigned RBs


Resource allocation versus time

PUCCH
allocation

No resource
scheduled
PUSCH allocation, different #RB and RB offset


TTI based scheduling


LTE scheduling impact on power versus time

TTI based scheduling.
Different RB allocation
Impact
on UE
power


Transmit signal quality


Transmit signal quality – carrier leakage

Frequency error

fc Fc+ε f

Carrier leakage (The IQ origin offset) is an additive sinusoid waveform
that has the same frequency as the modulated waveform carrier frequency.
Parameters Relative Limit (dBc)

Output power >0 dBm -25

-30 dBm ≤ Output power ≤0 dBm -20

-40 dBm  Output power < -30 dBm -10


Frequency Error
…. ability of both the receiver and the transmitter to process frequencies
correctly…

The 20 frequency error Δf results must fulfil this test requirement:
|Δf| ≤ (0.1 PPM + 15 Hz)
observed over a period of one time slot (0.5ms)


Impact on Tx modulation accuracy evaluation
l 3 modulation accuracy requirements
l EVM for the allocated RBs
l LO leakage for the centred RBs ! LO spread on all RBs
l I/Q imbalance in the image RBs
LO leakage
level
RF carrier

signal I/Q imbalance

noise

RB0 RB1 RB2 RB3 RB4 RB5 frequency

EVM


Inband emissions
3 types of inband emissions: general, DC and IQ image

Used
allocation <
½ channel
bandwidth

channel bandwidth

Carrier Leakage
Carrier leakage (the I/Q origin offset) is a form of interference caused by crosstalk or DC offset.
It expresses itself as an un-modulated sine wave with the carrier frequency.
I/Q origin offset interferes with the center sub carriers of the UE under test.
The purpose of this test is to evaluate the UE transmitter to verify its modulation quality in
terms of carrier leakage.

DC carrier leakage
due to IQ offset

LO Parameters Relative
Leakage Limit (dBc)

Output power >0 dBm -25

-30 dBm ≤ Output power ≤0 dBm -20
-40 dBm  Output power < -30 dBm -10


Inband emmission – error cases
DC carrier leakage
due to IQ offset


Inband image
due to IQ inbalance


DC leakage and IQ imbalance in real world …


UL Modulation quality: Constellation diagram
LTE PUSCH uses
QPSK, 16QAM
and 64 QAM (optional)
modulation schemes.
In UL there is only 1 scheme
allowed per subframe


Error Vector Magnitude, EVM
Q
Magnitude Error (IQ error magnitude)

Error Vector
Measured
Signal
Ideal (Reference) Signal
Φ
Phase Error (IQ error phase)

I

Reference Waveform
011001… Ideal
Demodulator
Modulator -
Input Signal
Σ Difference Signal
+

Measured Waveform


7 symbols / slot
0123456 0123456 0123456 0123456 time

PUSCH symbol
frequency
Demodulation Reference
symbol, DMRS

Limit values
Unit Level

Parameter
QPSK % 17.5
16QAM % 12.5
64QAM % [tbd]


CP center
1 SC-FDMA symbol, including Cyclic Prefix, CP
OFDM
Cyclic Symbol
prefix Part equal
to CP
FFT Window size

FFT window size depends
on channel bandwidth and
extended/normal CP length


CP center
1 SC-FDMA symbol, including Cyclic Prefix, CP
OFDM
Cyclic Symbol
prefix Part equal
to CP
FFT Window size

FFT window size depends on channel bandwidth
and extended/normal CP length
Cyclic prefix length

N cp Ratio of
N cp Cyclic prefix EVM
Channel W to CP
for symbols 1 Nominal for symbols window
Bandwidt for symbol 0 for
to 6 FFT size 1 to 6 in FFT length
h MHz symbols 1
samples W
to 6*
FFT window does
1.4 128 9 [5] [55.6]

3 256 18 [12] [66.7]
not capture the
5 512 36 [32] [88.9]
full length: OFDM
10
160 144
1024 72 [66] [91.7] Symbol + CP
15 1536 108 [102] [94.4]

20 2048 144 [136] [94.4]

* Note: These percentages are informative and apply to symbols 1 through 6. Symbol 0 has a
longer CP and therefore a lower percentage.
Table from TS 36.101 for normal CP


LTE Measurement: How to test a device

LTE Measurement: How to test a device

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