Operating OpenAirInterface in mmWave band · Mmwave Phase array front-end module 5 . ... Symbol 1 1 C P 1 Symbol 0 C P 0 Symbol 1 C P 1 72 1024 72 1024 72 1024 72 1024 136 1024 72

Operating OpenAirInterface in mmWave band

Ren-Jr Chen

[email protected] M300/ICL/ITRI 2019/12/4

Copyright 2019 ITRI 工業技術研究院

Agenda

Overview of OAI operating in mmwave band (28GHz)

Mmwave phase array module EVM test

Beamforming test

Stability test

OAI code test Test LDPC decoding performance

Test OAI code through phase array module

2


Overview of OAI operating in mmwave band (28GHz)

3


Components

OAI code version:

OAI git-version: branch: develop-nr, commit-id=26f1e090 08/23/2019

Baudrate: 61.44MHz, SISO I/Q, FFT SIZE:2048, CS:30kHz

Ethernet throughput: 61.44MHz x 32 bits ~= 1.966 Gbps

Computer model: (DIY computer)

CPU: Intel i7-9700K 3.6GHz

DDR: DDR4 32GB

OS: Ubuntu 16.04 (real-time kernel 4.4.15-rt23)

Mmwave phase array module

ITRI software define radio

4


Mmwave Phase array front-end module

5


Summary of mmwave module

Two streams, each stream for different polarization, including IF to RF upconverter, PA, LNA, phase shift, VGA, TX/RX switch …

9.6cm

15

cm

PA

PA

PA

PA

LO

IF

IF

5bits 5bits16 PAs

LNA

LNA

LNA

LNA

LO

IF

IF

5bits 5bits

16 LNA

16 PAs

16 LNA

2.5GHz~4GHz

2.5GHz~4GHz

RF:~28GHz, 800MHz BW


Polarization

7

Vertical direction feeding point

Horizontal direction feeding point


How many stream is better?

Which one is better?

8

PA

PA

DAC

PA

PA

ADC

PA

PA

DAC

PA

PA

ADC

H-pol

V-pol

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

PA

PA

ADC

PA

PA

ADC

H-pol

V-pol

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

PA

PA

ADC

PA

PA

ADC

H-pol

V-pol

PA

PA

ADC

PA

PA

ADC


Rank Issue in beamforming

rank?

BF ℎ11 ℎ21ℎ12 ℎ22

… ℎ𝑛1… ℎ𝑛2

⋮ ⋮ℎ1𝑚 ℎ2𝑚

⋱ ⋮… ℎ𝑚𝑛

9

PA

PA

DAC

PA

PA

ADC

PA

PA

DAC

PA

PA

ADC

: Dual polarization (7m) : Same polarization (7m)


Polarization in beamforming

Polarization could help the rank condition in two layers beamforming

10

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

PA

PA

DAC

Fixed antenna element Fixed array antenna gain


Rank Issue in beamforming

11


EVM Test

Overall EVM from TX to RX

12

BS

UE

Energy Surface

SC/CASE/EVM

SDR+RF

15K -30.9

30K -31.2

60K -31.4

120K -31.4

240K -31.4

../../Project/BP案/SDR_platform/2019/DEMO/中正/ES Demo Video(trailer).wmv


Fast beamforming capability

How fast we need?

Subfram 0

Slot 0

0.586 ms8.333 ms

9.440 ms

Subfram 1 Subfram 2 Subfram 91 frame = 10 subframes

1 subframe = 8 slots

1 slot = 14 OFDM symbols

1 radio frame = 10 ms

1.0 ms

125.391 ms

1.107 ms8.333 ms

8.919 ms

Slot 1

124.870 ms

Symbol 13CP

1

Symbol 2CP

1Symbol 1C

P1

0.586 ms8.333 ms

8.919 ms

1 slot = 14 OFDM symbols

0.586 ms8.333 ms

8.919 ms

Symbol 13CP

1

Symbol 2CP

1

Symbol 1CP

1

Symbol 0CP

0

Symbol 1CP

1

72 1024 72 1024 72 1024 72 1024

72 102472 102472 1024136 1024

15408 15344

122880 122880 122880 122880

Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 Slot 7

1540815344 15344 15344 15344 15344

125.391 ms 124.870 ms

13


Fast beamforming issue

TDL-A channel, Frequency band : 28GHz, CS=120kHz

14


How to Control mmwave module?

Preload your wanted beam pattern into mmwave module

Select beam pattern when TX and RX

15


Define and Preload Beam Pattern

16

PA

PA

PA

PA

LO

IF

IF

5bits 5bits16 PAs

16 PAs

8 beam table

8 beam table

Transmit

Beamforming

H-pol

V-pol

LNA

LNA

LNA

LNA

LO

IF

IF

5bits 5bits

16 LNA

16 LNA

8 beam table

8 beam tableH-pol

V-pol

Received

Beamforming

H_TX_Phase{1,3} = [0 45 90 135; 0 45 90 135; 0 45 90 135; 0 45 90 135]

H_TX_Att{1,3} = [10 10 10 10; 10 10 10 10; 10 10 10 10; 10 10 10 10]

H_TX_Att=cell(1,8);

H_TX_Phase=cell(1,8);

H_RX_Att=cell(1,8);

H_RX_Phase=cell(1,8);

V_TX_Att=cell(1,8);

V_TX_Phase=cell(1,8);

V_RX_Att=cell(1,8);

V_RX_Phase=cell(1,8);

Reference point


SS Block

17

Subframe #0 Subframe #1 Subframe #2 Subframe #3 Subframe #4 Subframe #5 Subframe #6 Subframe #7 Subframe #8 Subframe #9

#0Beam #1

Slot #0 Slot #1 Slot #2 Slot #3 Slot #4 Slot #5 Slot #6 Slot #7

#2 #3 #4 #5 #6 #7

4 8 16 20 32 36 44 48 60 64 72 76 88 92 100 104

#8 #9 #10 #11 #12 #13 #14 #15

Subframe #0


Subframe #1


Subframe #2

144 148 156 160 172 176 184 188 200 204 212 216 228 232 240 244


Subframe #3


Subframe #4

284 288 296 300 312 316 324 328 340 344 352 356 268 372 380 384 424 428 436 440 452 456 464 468 480 484 492 496 508 512 520 524

PSS SSS PBCH

#0Beam #1


#2 #3 #4 #5 #6 #7

4 8 16 20 32 36 44 48 60 64 72 76 88 92 100 104

#8 #9 #10 #11 #12 #13 #14 #15

Subframe #0


For Example

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Beam Tracking Test

19

B1 B2 B3 B4 B1 B2 B3 B4 B1 B2 B3 B4 B1 B2 B3 B4

B1 B2 B3 B4

BS:

UE:

../../Project/BP案/SDR_platform/2019/DEMO/VIDEO0646.mp4


Test mmwave stability

20

Transmission without any error packet last one week

One packet: 1500 bytes (one maximum IP)

Throughput: ~ 100 Mbps


Test OAI code structure

21

while (1)

RX();

Process_RXdata();

Prepare_TXdata();

TX();

end

while (1)

RX();

Process_RXdata();

Prepare_TXdata();

TX();

end

BS UE


Modify Interface Between PC and FPGA

PC -> FPGA (TX)

22

⋮


Modify Interface Between PC and FPGA

FPGA -> PC (RX)

23

⋮


LDPC decoding test

24


LDPC decoding test

OAI gNB/UE configuration:

Support Downlink : PBCH +DLSCH

SCS=30KHz (one slot=0.5ms), Sampling-Rate: 61.44 MHz ,fft=2048 , Total-PRB=106 (BW=40M),

DLSCH PRB=50PRB .

OFDM Symbol of DLSCH=9 (one slot consists of 14 OFDM symbols , 9 OFDM symbols for DL-Data)

NO parallel LDPC decode in UE

We try to enable “parallel LDPC decode” ,but we encounter error in MA-CPDU when we enable “parallel LDPC decode”. So all the test of LDPC we use is sequential decode.

25


LDPC decoding test

LDPC Decoding Time for PRB=50

26


LDPC decoding test

27


Modify OAI structure for Test OAI code

28

while (1)

Prepare_TXdata();

TX();

Process_RXdata();

RX(); % listen

end

while (1)

RX(); %listen

Process_RXdata();

Prepare_TXdata();

TX();

end

BS UE


OAI MCS-9 + RF-Cable without CFO Compensation

29


OAI MCS-15 + 28G mmWave 4x2 RF with CFO = 2320

30


DEMO in this workshop

5GNR OAI code

31

Beam tracking and real-time DEMO


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Documents

Operating OpenAirInterface in mmWave band · Mmwave Phase array front-end module 5 . ... Symbol 1 1 C P 1 Symbol 0 C P 0 Symbol 1 C P 1 72 1024 72 1024 72 1024 72 1024 136 1024 72