measurement methodology and post processing(2)

8/2/2019 Measurement Methodology and Post Processing(2)

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DRAFT

Measurement Methodology and Post Processing

for LTE Evaluation

Prepared by:

Florian Kaltenberger, Raymond Knopp

Mobile Communications Department

EURECOM, Sophia Antipolis

24.03.10

Version history:

Date Version Author Comment

13.9.2009 0.1 FK First draft

22.2.1010 0.2 GS First comments

2.3.2010 0.3 FK Response to comments

8.3.2010 0.4 FK Minor edits and clarifi-

cations


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Table of ContentsTable of Contents ............................................................................................................................ 2

1 Introduction ............................................................................................................................ 3

2 Measurement Equipment ....................................................................................................... 3

2.1 Hardware .......................................................................................................................... 3

2.1.1 Enhanced Node B ...................................................................................................... 3

2.1.2 User Equipment ........................................................................................................ 3

2.2 Software ........................................................................................................................... 3

2.2.1 PHY measurements ................................................................................................... 4

2.2.2 Two-way wideband MIMO channel estimates. ........................................................ 5

2.2.3 GPS location tracking (UE only) ................................................................................ 5

2.2.4 PDCH (UE only) .......................................................................................................... 5

2.2.5 Throughput measurements ...................................................................................... 5

2.2.6 Overall structure that is stored to disk ..................................................................... 7

3 Measurement Methodology ................................................................................................... 7

3.1 Measurement Sites .......................................................................................................... 7

3.2 Link Budget ....................................................................................................................... 7

3.3 Objectives to be achieved by the measurements ............................................................ 9

3.4 Measurement Procedure ............................................................................................... 10

4 Post processing ..................................................................................................................... 11

4.1 Throughput post processing .......................................................................................... 11

4.2 List of figures to be produced ........................................................................................ 12

5 Data integrity and quality verification .................................................................................. 15

6 Data elaboration flow ........................................................................................................... 15

7 References ............................................................................................................................ 15


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1 Introduction2 Measurement Equipment2.1 Hardware2.1.1 Enhanced Node B2.1.2 User Equipment2.2 SoftwareThe measurement software runs on the host PCs (both eNB and UE) on top of the LTE software

modem. It allows to control the modem (such as the MIMO mode) as well as to visualize vari-

ous channel parameters.

Figure 1: GUI for measurement software

The measurement software allows the real-time acquisition of the following real-time radio pa-

rameters:


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2.2.1 PHY measurementsIn the following we list the measurements that are estimated and stored at the UE and the

eNodeB. These measurements are independent of the transmission mode.

2.2.1.1Common PHY Measurements (UE and eNb)rx_power[NUMBER_OF_eNB_MAX][NB_ANTENNAS_RX] estimated received signal power

(linear)

n0_power[NB_ANTENNAS_RX] estimated noise power (linear)

rx_power_dB[NUMBER_OF_eNB_MAX][NB_ANTENNAS_RX] estimated received signal power

(dB)

rx_spatial_power[NUMBER_OF_eNB_MAX]

[NB_ANTENNAS_RX][NB_ANTENNAS_TX]

estimated received spatial signal

power (linear)

rx_spatial_power_dB[NUMBER_OF_eNB_MAX]

[NB_ANTENNAS_RX][NB_ANTENNAS_TX]

estimated received spatial signal

power (dB)

rx_avg_power_dB[NUMBER_OF_eNB_MAX] estimated avg received signal

power (dB)

rx_rssi_dBm[NUMBER_OF_eNB_MAX] estimated rssi (dBm)

n0_power_dB[NB_ANTENNAS_RX] estimated noise power (dB)

n0_avg_power_dB estimated avg noise power (dB)

rx_correlation[NUMBER_OF_eNB_MAX]

[NB_ANTENNAS_RX]

estimated correlation (wideband

linear) between spatial channels

rx_correlation_dB[NUMBER_OF_eNB_MAX]

[NB_ANTENNAS_RX]

estimated correlation (wideband

dB) between spatial channels

2.2.1.2UE PHY Measurementswideband_sinr[NUMBER_OF_eNB_MAX] Estimated wideband SINR

subband_sinr[NUMBER_OF_eNB_MAX]

[NUMBER_OF_SUBBANDS];

Estimated subband SINR

wideband_cqi[NUMBER_OF_eNB_MAX] Estimated wideband CQI (feed-

back)

subband_cqi[NUMBER_OF_eNB_MAX]

[NUMBER_OF_SUBBANDS]

Estimated subband CQI (feedback)

wideband_pmi[NUMBER_OF_eNB_MAX]

[NB_ANTENNAS_RX];

Estimated wideband PMI per RX

antenna (feedback)

subband_pmi[NUMBER_OF_eNB_MAX] Estimated subband PMI per RX an-


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[NUMBER_OF_SUBBANDS] [NB_ANTENNAS_RX]; tenna (feedback)

selected_rx_antennas; chosen RX antennas (1=Rx antenna

1, 2=Rx antenna 2, 3=both Rx an-

tennas)

2.2.2 Two-way wideband MIMO channel estimates.1. UE: We store the channel estimates from the reference symbols (RS) of the first sub-

frame in every frame. This corresponds to 937.5kbyte/sec (= 4 byte/sample * 2 RX an-

tennas * 300 subcarriers * 4 OFDM symbols * 100 frames) or 3.3Gbyte/h.

2. eNb: We store the channel estimates from the sounding reference symbols (SRS) whichis every subframe. This corresponds to 1172 kbyte/sec (= 4 byte/sample * 2 RX antennas

* 300 subcarriers * 5 OFDM symbols * 100 frames) or 4.12Gbyte/h

2.2.3 GPS location tracking (UE only)The locations (latitude, longitude, altitude, speed) are stored every second (every 100 LTE

frames) along with the measurement data.

2.2.4 PDCH (UE only)Contains the unique frame number that allows aligning the data with the one from the op-

posite link. We also record the frame error rates on the PDCH.

2.2.5 Throughput measurementsThroughput measurements will be collected at different levels of the protocol stack as shown in

Figure 2.

PHY

Modulation

PHY Coding

MAC

RLC

IP

IP Throughput

RLC Throughput

Uncoded Throughput

MAC Throughput (without

signalling, with HARQ)


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Figure 2: Different throughput measurements

2.2.5.1Uncoded throughput & MAC throughputThe coded and the uncoded throughput can be derived from the DCI and the UCI PDU, which

we store both at the UE and the eNb.

The DCI (Downlink Control Information) transports downlink or uplink scheduling information,or uplink power control commands for one RNTI (Radio Network Temporary Identifyer).

Length of DCI in bits unsigned char dci_length;

Aggregation level unsigned char L;

rnti unsigned short rnti;

Format DCI_format_t format;

DCI pdu unsigned char

dci_pdu[1+(MAX_DCI_SIZE_BITS/8)];

The format can be one of the following

format0, format1, format1A, format1B, format1C,

format1D, format2, format2_2A_L10PRB, format2_2A_M10PRB, format2_4A_L10PRB, format2_4A_M10PRB, format2A_2A_L10PRB, format2A_2A_M10PRB, format2A_4A_L10PRB, format2A_4A_M10PRB,

format3Each format has a specific number of bits, which are stored in the PDU field. See 3GPP 36.212

(v8.6) for details. This control information allows to recover the Coding and Modulation scheme

and the number of allocated ressource elements. It also contains information of the HARQ pro-

cesses. Thus we can recover the throughput with and without HARQ. It also contains the sche-

duling allocations for the uplink, which allows to recover the UL througput as well.


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2.2.5.2RLC throughput (openair2)To measure the throughput at the MAC and the RLC we store the variables UE_mac_inst (type

UE_MAC_INST) at the UE and the variable CH_mac_inst (typeCH_MAC_INST) at the eNb once a

(sub?)frame.

2.2.6 Overall structure that is stored to disk2.2.6.1Openair1struct fifo_dump_emos_struct_UE {

RTIME timestamp; //! Timestamp of the receiver

unsigned int frame_tx; //! Framenumber of the TX (encoded in the BCH)

unsigned int frame_rx; //! Framenumber of the RX

PHY_MEASUREMENTS PHY_measurements; //! Structure holding all PHY measurements

char pbch_pdu[NUMBER_OF_eNB_MAX][PBCH_PDU_SIZE]; /// Contents of the PBCH

unsigned int pdu_errors[NUMBER_OF_eNB_MAX]; /// Total number of PDU

errors

unsigned int pdu_errors_last[NUMBER_OF_eNB_MAX]; /// Total number of PDU

errors 128 frames ago

unsigned int pdu_errors_conseq[NUMBER_OF_eNB_MAX]; /// Total number of con-secutive PDU errors

unsigned int pdu_fer[NUMBER_OF_eNB_MAX]; /// FER (in percent)

DCI_type_t DCI_format[MAX_DCI_PER_FRAME]; /// chosen DL format

(DCI)

char DCI_pdu[MAX_DCI_PER_FRAME][6]; /// content of DCI

UCI_type_t UCI_format[MAX_UCI_PER_FRAME]; /// chosen feedback for-

mat (UCI)

char UCI_pdu[MAX_UCI_PER_FRAME][5]; /// content of the feed-

back information

int timing_offset; /// Timing offset

int freq_offset; /// Frequency offset

unsigned int rx_total_gain_dB; /// Total gain

int chan-

nel[NUMBER_OF_eNB_MAX][NB_ANTENNAS_RX*NB_ANTENNAS_TX][N_RB_DL_EMOS*N_PILOTS_PER_RB*N_SLOTS_EMOS];

};

2.2.6.2Openair23 Measurement Methodology3.1 Measurement SitesPossible measurement sites include:

81320 / MURAT-SUR-VEBRE 81320 / BARRE 81530 / VIANE

3.2 Link BudgetLink budget to be detailed down to the components (power compared to sensitivity and SNR

with noise factor) both for DL and UL + to derivate for all channels.

To be expressed as Excel sheet so as to agree on the formulas.

A link budget has been established based on the following assumptions:
http://www.openairinterface.org/docs/html/structUE__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structUE__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structCH__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structCH__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structCH__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structCH__MAC__INST.htmlhttp://www.openairinterface.org/docs/html/structUE__MAC__INST.html


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Path loss model for 800MHz channel: Okumura-Hata model [COST231] Path loss model for 2.6GHz: WINNER D1 [WINNER] DL Link Budget is based on the 5MHz reference channel defined in 36.101-851 Annex

A.3.2 (~2Mbit/sec)

UL Link Budget is based on the 1.4MHz reference channel A4.2 defined in 36.104-850Anex A.1 (~580kbit/sec)

Figure 3: Path loss models for urban scenarios

Column1 UHF 2.6GHz Comments

Tx power 43 43

Tx antenna gain 14 17

EIRP (dBm) 57 60

Rx sensitivity -98 -98 as defined in 36.101-851 7.3.1

Total margin 155 158

Distance (km) 32 18Figure 4: Downlink link budget

Column1 UHF 2.6GHz Comments

Tx power 23 23

Processing gain 6,2 6,2 minimum #RB in uplink: 6


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Rx antenna gain 14 17

Rx sensitivity -101,5 -101,5 as defined in 36.104-850 7.2.1

Total margin 144,7 147,7

Distance (km) 22,5 9,3Figure 5: Uplink link budget

Figure 6: Coverage regions for measurement sites based on UL link budget

3.3 Objectives to be achieved by the measurementsThe goal of the measurements is to show the best throughput a real LTE release 8 nomadic

terminal will be able to get in every location in the coverage area of each of the three sites.

This implies:

- covering all the road network in each of the areas -> this requires first to identify thereal limits of the coverage areas (a first estimate can be done with theoretical radio

planning prior to the verification; the real limits will be identified during a pre-test as

outlined in the test plan),

- demonstrating that the measurements obtained with vehicular antennas are transpos-able to outdoor nomadic antennas (since it is chosen to make most measurements in

vehicular conditions so as to make measurements quicker) -> this suggests that some

measurements shall be done in sufficient locations with nomadic antennas in out-of-

vehicular conditions to calibrate the vehicular-nomadic delta conditions,


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- demonstrating that mobile measurements are representative of fixed measurements,this requires :

o fixed point measurements both with outdoor vehicular antennas and outdoornomadic antennas,

o a method to translate the performance of the MODEM at vehicular speed tonomadic speed (this might be based on the instantaneous SNR and/or the wide-band channel measurements),

o to define a speed limit when measuring in vehicular conditions ?- measuring (or as a minimum extrapolating) the best throughput the terminal will get

with the most appropriate modulation-coding-puncturing-MIMO scheme and LTE re-

lease 8 compliant performances. To this end we will carry out measurements with and

without link adaptation as outlined in the next section,

- demonstrating that the physical channels implementation in the e-nodeB and terminalis representative of LTE release 8 behavior (based on the non-compliance clause in thecontract while more precise),

- demonstrating that the handover between sectors of the e-nodeB is representative of areal e-nodeB or how it can be translated,

- demonstrating that the measurements in TDD mode are representative of FDD mode(overheads, signalization).

3.4 Measurement ProcedureThroughput measurements will be conducted for different transmission modes. We will do ac-

tual throughput measurements for three different LTE transmission modes:

1: Single antenna transmission (with link adaptation and with one fixed coding and

modulation scheme)

2: Transmit diversity (Alamouti)

6: Closed loop rank1 precoding

The throughput of the following transmission modes will be extrapolated from the UE PHY

measurements (see Section 4 for details)

4: Closed loop spatial multiplexing

5: MU-MIMO

The transmission mode has to be set at the eNB prior to the measurement run.

Before starting the actual measurements, the coverage of the eNB shall be calibrated using the

procedure described in the test plan.

A route that covers as much as possible of the cell shall be identified. It is estimated that the

covered area corresponds to about 200-300km of roads for the 800MHz configuration. The

route shall include zones with and without LOS, for high speed tests, villages with street can-

yons and zones for nomadic tests. Checkpoints shall be included on the routes at least every 30


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min. The routes shall be documented using a log (including photos and or videos). In any case

one measurement should not take longer than 4-6h, making it possible to finish it in one day.

One measurement run will result in apx. 16-24 Gbytes of data that should be copied to an ex-

ternal hard disk at the end of the day. The integrity of the files shall be checked using the pro-

cedures outlined in the test plan.

For information how to use the EMOS software to conduct the measurements please refer to

the user manual.

4 Post processingThe recorded measurements will be post-processed in Matlab. Import filters to load the meas-

urement data into Matlab will be provided.

4.1 Throughput post processingThe following table lists all the LTE transmission modes. The ones in green will be measured,

while the ones on red are not implemented in the current version of the test bench. The ones inorange can be extrapolated from the recorded UE measurements. Also throughput curves with

different receive processing (1 RX antenna instead of two) can be extrapolated.

By default, there is automatic link adaptation for all modes. For the single antenna transmission

mode there will also be one measurement with a fixed modulation and coding scheme.

Transmission

Mode

Actual RX processing for

throughput measure-

ments

Extrapolated Throughput

in post processing

1: Single antenna SIMO SISO

2: Transmit diver-

sity (Alamouti)

SIMO SISO

3: Open Loop Spa-

tial Multiplexing

not implemented

4: Closed loop spa-

tial multiplexing

full RX for 2 layers not

implemented

MIMO with RI=2 through-

put extrapolated from

measurements of mode 6

5: MU-MIMO only one UE available MU-MIMO throughput

extrapolated from meas-

urements of mode 6

6: Closed looprank1 precoding

MIMO MISO

7: UE-specific not implemented


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4.2 List of figures to be produced RSSI indicators (UL/DL) across the test cell (based on measurement 1 and 5). The data

will be visualized in several ways:

o overlaid a real map using the recorded GPS coordinates (see Figure 7 for an ex-ample).

o plotted as a function of the distance from the base station (path loss)o plotted as a function of the distance traveled by the measurement car (allows to

compare different measurement runs given that the measurement routes were

the same).

Ricean factor. Achievable instantaneous throughput (UL/DL) on data channels (based on measurement

3, 4, and 5). The data will be visualized in several ways:

o overlaid a real map using the recorded GPS coordinates (see Figure 7 for an ex-ample).

o plotted as a function of the distance from the base stationo plotted as a function of the speed of the UEo plotted as a function of the distance traveled by the measurement car (allows to

compare different measurement runs given that the measurement routes were

the same).

Figure 7: RSSI in a measured cell

Curves showing throughput as a function of the UE-enodeB distance :


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o with superposition of the curves for all measured and extrapolated transmissionmodes as outlined in Section 4.1,

o with superposition of either fixed modulation-coding-puncturing-MIMO schemeor (real and theoretical) link adaptation,

o with superposition automatic MIMO coexistence between single stream (trans-mit diversity) and multi-stream (spectral multiplexing),o for all levels of throughputs (as shown in Figure 2),o Both for DL and UL.o Extrapolation for FDD.

Curves showing throughput as a function of distance traveled :o with superposition of the curves for all modulation-coding-puncturing-MIMO

modes either really measured or theoretically extrapolated,

o with superposition of either fixed modulation-coding-puncturing-MIMO schemeor (real and theoretical) link adaptation,o with superposition automatic MIMO coexistence between single stream (trans-

mit diversity) and multi-stream (spectral multiplexing),

o in case of link adaptation (either real or theoretical), add information of the in-stantaneous scheme for the e-nodeB-UE link,

o for all levels of throughputs,o with speed,o with Ricean factor,o Both for DL and UL.o Extrapolation for FDD.

Curves showing throughput as a function of speed :o with superposition of the curves for all modulation-coding-puncturing-MIMO

modes either really measured or theoretically extrapolated,


o with superposition automatic MIMO coexistence between single stream (trans-mit diversity) and multi-stream (spectral multiplexing),

o for all levels of throughputs,o Both for DL and UL.o Extrapolation for FDD.

Curves showing throughput as a function of the Ricean factor :


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o with superposition of the curves for all modulation-coding-puncturing-MIMOmodes either really measured or theoretically extrapolated,


o with superposition automatic MIMO coexistence between single stream (trans-mit diversity) and multi-stream (spectral multiplexing),o for all levels of throughputs,o Both for DL and UL.o Extrapolation for FDD.

Extrapolation to cell loaded with other terminals (use of Proportionally Fair as Nokia ?). Distributions of capacity (outage events) for constant bit-rate services (based on meas-

urement 2).

Figure 8: Example of capacity distribution

Please describe how :

- GPS coordinates will be translated into distance traveled, especially how to cope withthe fact that in urban environment GPS position may jump backwards or sideway.

- Two sets of measurements made on the same path at different times will be correlated,especially if on one of the path is slightly different to the other due for instance to a

blocked street or road. Typically, it was agreed end of December that a method based

on total path distance complemented with check points on the path (typically every

crossraod) and manual suppression of unshared sections.


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5 Data integrity and quality verificationDescription of the post-processing verifying the quality of the data acquired (while not generat-

ing all curves).

6

Data elaboration flowDetail (scheme + formulas) the way raw data stored by the e-nodeB and UE are elaborated intoall the data needed to show the end results.

Detail how all data files will be stored before generating the curves.

7 References[WINNER] Kyosti, P.; Meinila, J.; Hentila, L.; Zhao, X.; Jamsa, T.; Schneider, C.; Narandzic, M.;

Milojevic, M.; Hong, A.; Ylitalo, J.; Holappa, V.; Alatossava, M.; Bultitude, R.; de Jong, Y. & Rau-

tiainen, T., WINNER II Channel Models, Project Deliverable, European Commission, 2007

[COST231] E Damosso, LM Correia Digital Mobile Radio Towards Future Generation Systems,

COST 231 Final Report, European Commission, 1999

measurement methodology and post processing(2)

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