LTE Measurement: How to test a device
This course provides an overview with practical examples and exercises on how to test a LTE-capable device while performing standardized RF measurements such as power, signal quality, spectrum and receier sensitivity, and how to automate these measurements in a simple and cost-effective way. We will present testing of LTE handsets in terms of protocol signaling scenarios and handover to other radio technologies for interoperability. This course will demonstrate end-to-end (E2E), throughput and application testing using the Rohde & Schwarz R&S®CMW500 Wideband Radio Communication Tester. Examles of application tests are voice over LTE, (VoLTE) or Video over LTE.
1. 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 -
This folder may be taken outside ROHDE & SCHWARZ facilities.
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
2. 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
4. 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
November 2012 | LTE measurements| 4
5. 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
November 2012 | LTE measurements| 5
6. Mobile Radio Testing
Generate downlink Generate downlink
signal and send signal
signaling information No signaling Control PC
Signaling testing Non-Signaling testing
November 2012 | LTE measurements| 6
8. 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
November 2012 | LTE measurements| 8
9. LTE RF Testing Aspects
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
November 2012 | LTE measurements| 9
10. LTE RF Testing Aspects
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
November 2012 | LTE measurements| 10
11. LTE RF Testing Aspects
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
November 2012 | LTE measurements| 11
12. 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
November 2012 | LTE measurements| 12
14. 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
November 2012 | LTE measurements| 14
15. Test Environment – Test System Uncertainty
36.101 / 36.508
• Temperature/Humidity
-normal conditions +15C to +35C, relative humidity 25 % to 75 %
-extreme conditions -10C to +55C (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]
November 2012 | LTE measurements| 15
17. OFDM risk: Degradation
Channel (ideal)
sl n rl n
1
TMC
Samples
f
f0 f1 f2 f3 f0 f1 f2 f3
November 2012 | LTE measurements| 17
18. OFDM risk: Degradation due to Frequency Offset
Channel
e j 2fn
sl n rl n
f
Samples
f
f0 f1 f2 f3 f0 f1 f2 f3
November 2012 | LTE measurements| 18
19. OFDM risk: Degradation due to Clock Offset
Channel
sl n rl n
f k
Samples
f
f0 f1 f2 f3 f0 f1 f2 f3
November 2012 | LTE measurements| 19
20. 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 2kf t N CP ,l Ts
N RB Nsc / 2
DL RB
sl( p ) t ak (p)) ,l e
(
ak( (p)) ,l e j 2kf 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
November 2012 | LTE measurements| 20
21. LTE: DC subcarrier usage
DC subcarrier or subcarrier 0 is not used in downlink!
November 2012 | LTE measurements| 21
22. 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!
November 2012 | LTE measurements| 22
23. 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.
November 2012 | LTE measurements| 23
24. 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
November 2012 | LTE measurements| 24
25. 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
November 2012 | LTE measurements| 25
27. 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
November 2012 | LTE measurements| 27
Date: 21.AUG.2008 15:51:00
28. 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!
November 2012 | LTE measurements| 28
30. 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
November 2012 | LTE measurements| 30
31. Spurious emissions – operating band excluded
November 2012 | LTE measurements| 31
32. 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
November 2012 | LTE measurements| 32
33. 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
November 2012 | LTE measurements| 33
34. Base station receiver test
Example: Rx test, moving condition
70% of required throughput of FRC, Fixed Reference Channel
November 2012 | LTE measurements| 34
35. Base station receiver test – HARQ multiplexing
UE sends PUSCH with alternating data
and data with multiplexed ACK
November 2012 | LTE measurements| 35
36. 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
November 2012 | LTE measurements| 36
38. 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
November 2012 | LTE measurements| 38
39. 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
November 2012 | LTE measurements| 39
41. 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
November 2012 | LTE measurements| 41
42. 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
November 2012 | LTE measurements| 42
43. 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
November 2012 | LTE measurements| 43
44. 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
November 2012 | LTE measurements| 44
45. 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
November 2012 | LTE measurements| 45
46. 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
November 2012 | LTE measurements| 46
47. 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
November 2012 | LTE measurements| 47
48. 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
November 2012 | LTE measurements| 48
49. 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 - - - - -
November 2012 | LTE measurements| 49
50. 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
52. Pcmax definition – tolerance values
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
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
November 2012 | LTE measurements| 52
53. Pcmax definition – tolerance values
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
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
November 2012 | LTE measurements| 53
54. Pcmax value for power control - analogies
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
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
November 2012 | LTE measurements| 54
55. 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
November 2012 | LTE measurements| 55
56. 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
November 2012 | LTE measurements| 56
57. 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
November 2012 | LTE measurements| 57
58. UE maximum power
PPowerClass + 2dB
23dBm
PPowerClass - 2dB
maximum output FUL_high
FUL_low power for any
transmission bandwidth
within the channel bandwidth
November 2012 | LTE measurements| 58
59. 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
November 2012 | LTE measurements| 59
60. UE maximum power - examples
Example 1: No maximum power reduction by higher layers
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 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
November 2012 | LTE measurements| 60
61. UE maximum power - examples
Example 2: max cell power = 0 dBm + band edge maximum power reduction
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
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
November 2012 | LTE measurements| 61
62. UE maximum power - examples
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_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
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
November 2012 | LTE measurements| 62
63. UE maximum power - examples
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
PCMAX_L– T(PCMAX_L) ≤ PCMAX ≤ PCMAX_H + T(PCMAX_H)
PCMAX_L = min{PEMAX_L, PUMAX } PCMAX_H = min{PEMAX_H, PPowerClass}
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
November 2012 | LTE measurements| 63
64. 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
November 2012 | LTE measurements| 64
65. 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
MHz MHz MHz MHz MHz MHz
Transmit OFF power -50 dBm
Measurement
1.08 MHz 2.7 MHz 4.5 MHz 9.0 MHz 13.5 MHz 18 MHz
bandwidth
November 2012 | LTE measurements| 65
66. 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
November 2012 | LTE measurements| 66
67. 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.
November 2012 | LTE measurements| 67
68. 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
MHz MHz MHz MHz MHz MHz
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
November 2012 | LTE measurements| 68
69. 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
MHz MHz MHz MHz MHz MHz
PCMAX test point 1 -10 dBm ± 7.7
PCMAX test point 2 10 dBm ± 6.7
PCMAX test point 3 15 dBm ± 5.7
November 2012 | LTE measurements| 69
70. 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
November 2012 | LTE measurements| 70
71. 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
November 2012 | LTE measurements| 71
72. 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
November 2012 | LTE measurements| 72
73. 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.
November 2012 | LTE measurements| 73
74. 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.
November 2012 | LTE measurements| 74
75. Power Control – Relative Power Tolerance
l Various power ramping patterns are defined
ramping down
alternating
ramping up
November 2012 | LTE measurements| 75
76. 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
November 2012 | LTE measurements| 76
77. 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)
November 2012 | LTE measurements| 77
78. 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
November 2012 | LTE measurements| 78
79. 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
FDD test patterns TDD test patterns
0 5 0 5 0 3 8 3 8 3
sub-frame# sub-frame#
November 2012 | LTE measurements| 79
80. UE aggregate power tolerance
Power Power
FDD test patterns TDD test patterns
0 5 0 5 0 3 8 3 8 3
sub-frame# sub-frame#
Test performed with scheduling gap of 4 subframes
November 2012 | LTE measurements| 80
81. 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
November 2012 | LTE measurements| 81
82. Power dynamics
PUSCH = OFF PUSCH = ON PUSCH = OFF time
Please note: scheduling cadence for power dynamics
November 2012 | LTE measurements| 82
83. 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
November 2012 | LTE measurements| 83
84. PRACH time mask
PRACH
ON power requirement
End of OFF power Start of OFF power
requirement requirement
20µs 20µs
Transient period Transient period
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
November 2012 | LTE measurements| 84
85. 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
End of OFF power Start of OFF power
requirement requirement
20µs 20µs
Transient period Transient period
November 2012 | LTE measurements| 85
90. 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
Transient period Transient period
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
November 2012 | LTE measurements| 90
91. 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
requirement requirement
20µs 20µs 20µs 20µs 20µs 20µs
Transient period Transient period Transient period
If intra-slot hopping is enabled
Periods where power changes may occur
November 2012 | LTE measurements| 91
92. Tx power aspects
RB power = Ressource Block Power, power of 1 RB
TX power = integrated power of all assigned RBs
November 2012 | LTE measurements| 92
93. Resource allocation versus time
PUCCH
allocation
No resource
scheduled
PUSCH allocation, different #RB and RB offset
November 2012 | LTE measurements| 93
97. 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
November 2012 | LTE measurements| 97
98. 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)
November 2012 | LTE measurements| 98
99. 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
November 2012 | LTE measurements| 99
100. Inband emissions
3 types of inband emissions: general, DC and IQ image
Used
allocation <
½ channel
bandwidth
channel bandwidth
November 2012 | LTE measurements| 100
101. 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
November 2012 | LTE measurements| 101
102. Inband emmission – error cases
DC carrier leakage
due to IQ offset
November 2012 | LTE measurements| 102
103. Inband emmission – error cases
Inband image
due to IQ inbalance
November 2012 | LTE measurements| 103
104. Inband emmission – error cases
Inband image
due to IQ inbalance
November 2012 | LTE measurements| 104
105. DC leakage and IQ imbalance in real world …
November 2012 | LTE measurements| 105
106. 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
November 2012 | LTE measurements| 106
107. 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
November 2012 | LTE measurements| 107
108. Error Vector Magnitude, EVM
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]
November 2012 | LTE measurements| 108
109. Error Vector Magnitude, EVM
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
November 2012 | LTE measurements| 109
110. Error Vector Magnitude, EVM
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
November 2012 | LTE measurements| 110