Florian Kaltenberger (Eurecom)

5th OAI workshop, BUPT, 22.6.2018

5G New Radio in OpenAirInterface

1

“Complete Stage-3 specifications on eMBB including support of low latency for E-UTRA-NR DC via EPC where the E-UTRA is the master until December 2017”

NR 3GPP timeline

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5G NR vs LTE : System Overview

Interworking with LTE : Standalone (SA) or Non Standalone (NSA)

L2/L3: New RRC INACTIVE state New L2 QoS layer: SDAP Reordering in PDCP instead of RLC, no RLC SDU concatenation MAC scheduling taking into account numerology Asynchronous HARQ in UL and DL

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5G NR vs LTE : Physical Layer

Up to 640 Mhz system bandwidth (100MHz below 6GHz)

Scalable numerology allows from 15 kHz to 480 kHz subcarrier spacing

Flexible TTI (1-14 OFDM symbols)

Channel coding : LDPC and Polar codes

Beam Management

Bandwidth Parts

Flexible TDD

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5G-ready OAI Demonstration at MWC18

Collaboration between TCL, Eurecom, Syrtem

Based on OAI 4G protocol stack for eNB and UE

80MHz bandwidth (4x overclocked LTE) Similar to 60kHz subcarrier spacing in NR

Based on custom build SDR from Syrtem (Xilinx Zynq + ADRV9371

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Use LDPC in downlink (instead of Turbo)– Very efficient software

implementation of both encoder and decoder (up to 150Mbps)

– Offload of LDPC decoder to FPGA for max throughput (300Mbps)

Notes on higher layer config

First specifications & deployments are for non-standalone operation (NSA)

all 5G control plane (RRC)

traffic transported over LTE, e.g., initial configuration

In our initial implementation this structure will be made available through a file at both gNB and UE

Notes on L1/L2 Interface

OpenAirInterface eNB uses FAPI for L1/L2 interface

Specified in SCF082.09.05 (Small Cell Forum, 2017-05-18) up to Rel 13 P5 – the PHY mode control interface

P7 – the main data path interface

Available in open-source from CISCO (https://github.com/cisco/open-nFAPI)

We are updating this spec to Rel15 for gNB

We are also specifying a similar interface for NR-UE

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5G-NR Hardware requirements

5G configurations supported by OAI

30khz subcarrier spacing: 40 MHz (106PRB, 1272 subcarriers, 38.15MHz eff. bandwidth)

• FFT size 2048 61.44MHz sampling rate

80MHz (217 PRB, 2604 subcarriers, 78.12MHz eff. bandwidth)

• FFT size 4096 sampling rate 122.88MHz, or

• FFT size 3072 sampling rate 92.16MHz (3/4 sampling)

60khz subcarrier spacing: 100MHz (132 PRB = 1584 subcarriers, 95.04MHz eff. bandwidth)

• FFT size 2048 sampling rate 122.88MHz,

• no 3/4 sampling possible

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Hardware for 5G-NR

USRP X310 USRP N310 SYRTEM SDR YunSDR Y450

Data acquisition Gbit EtherNet,PCIexpress

Gbit Ethernet PCIexpress PCIexpress, GbitEthernet, USB3

MIMO 2x2 MIMO, 4x4 MIMO 2x2 MIMO 2x2 MIMO

RF chip n/a** AD9371 (x2) AD9371 AD9371

Sampling rates 200 MHz, 184.32 MHz

122.88MHz, 125MHz, 153.6MHz

122.88MHz 122.88MHz

Frequency range DC-6GHz (dependson daughterbrd)

10 MHz – 6GHz 10 MHz – 6GHz 10 MHz – 6GHz

Price ~€5,000 ~€10,000 ??? ???

Duplexing FDD* or TDD* FDD* or TDD* FDD* or TDD* FDD* or TDD*

Output power n/a** 12-18dBm ??? 10dBm

Noise figure n/a** 5.5-7.5dB ??? ???

Open source FPGA/driver FPGA/Driver Limited ???

5G Compatibility 40MHz, 80MHz (with ¾ sampling)

40, 80, 100MHz 40, 80, 100MHz 40, 80, 100MHz

6/25/2018 10

*needs external RF elements

** depends on daughterboard

Current development status

One common branch for gNB and UE: develop-nr

Created new directory structures for eNB, LTE-UE, gNB, and NR-UE specific code

Created new executables lte-softmodem, nr-softmodem, lte-uesoftmodem, nr-uesoftmodem

introduced new structures for gNB and NR frame parameters

Development process

Develop-nr synchronized regularly with develop

Features branch of from and merge back to develop-nr

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Current development status gNB

PHY layer additions Phy_procedures_gNB_TX

NR-PSS and NR-SSS

Generic polar encoder and decoder

PBCH payload generation, scrambling, encoder

PBCH DMRS and PBCH modulation

Higher layers Import of 38.331 RRC messages using asn1c*

Generation of MIB

Application to read configuration file and program gNBRRC

RRC -> MAC configuration ongoing

NR FAPI-style interface ongoing for MAC->PHY configuration

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* New version of as1nc required to support new syntax and multiple specs: https://github.com/brchiu/asn1c/tree/s1ap

Current development status UE

Integrated/updated UE into new common 5g branch

PSS/SSS detection

PBCH RX channel estimation & compensation (demodulation) Decoder ready to be integrated

PDCCH RX Supported DCI formats: 00, 10 Functions to handle filling and demapping of fields (instead of static configurations like in

LTE)

PDSCH DMRS ready for validation

SRS TX Support periodic SRS Ready for validation

TDD Support semi static config UL asynchronous harq ongoing

PUCCH TX UCI started

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OAI 5G-NR ROADMAP

OAI 5G NR v1

Target: Aug 2018

Perf: same as v0

Planned features: ‘NSA’, NR Layer 1 DL 40MHz -80MHz SCS 30kHz DL CP-OFDM NR-SSS/PSS NR-PBCH NR-PDSCH NR-PDCCH

Prioritized additional features (open for 3rd party contribution)priority

Self-contained structure (requires symbol-based receiver) 1 Mini-slot 1 Add DCI formats 2 add. PRACH formats (list) 2 semi-persistent and aperiodic SRS (periodic SRS supported) 2 PDSCH DMRS other than front loaded ? 3

HW support: same as v0

IOT scope : OAI – OAI (PHY test mode)

OAI 5G NR v2

Target: Q3/18

Perf: same as v1 + Over The Air @ 3.5GHz

Planned features: L1 update, UL channels, TDD UL DFT-s-OFDM NR-PUCCH, NR-PUSCH & periodic SRS NR-TDD support (semi static config) OTA improvements (AGC, freq tracking)

Prioritized additional features (open for 3rd party contribution) priority LTE-NR Dual connectivity 1 Dynamic TDD 2 HARQ / Fast ACK 2 semi-persistent and aperiodic SRS 2 UL CP-OFDM 3

HW support: + RF front-end 3.5GHz

IoT scope : OAI – OAI full stack NSA/L3-LTE

Planned for Orange salon de rechercheDec. 2018!

OAI 5G NR v3

Target: Q4/18

Perf: 600Mb/s with FPGA v2

Planned features: MIMO & High-performance MIMO 4 layers decoder LDPC: enhanced SW version, opt. FPGAv2 full TP up to 4 HARQ processes with full TP FPGA LDPC RRC NSA

Prioritized additional features (open for 3rd party contribution) M-MIMO Beam tracking 1 Defined commercial IOT profile support 1 left-over v1-v2 1

HW support: v2 + new FPGA UltraScale+ w/ 4 streams support, LDPC full TP

IOT scope : OAI – OAI full stack + OAI UE - commercial gNodeB(tbc)

OAI 5G-NR further roadmap (2019)

Interoperability with commercial equipment

Ultra reliable low latency communication (UrLLC) < 2ms latency (RTD) 15-60kHz SCS Low throughput Option 1: relying on mini slot Option 2: relying on self contained structure

Massive MIMO French Project MASS-START 3.5Ghz and 28GHz band Support for up to 64 antennas (potentially hybrid

analogue-digital architecture) Up to 8 layers transmission (max 4 layers per user)

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Join the 5G-NR development

Current development team Hongzhi, Augustin, Jaques (TCL) Kenny, Calvin (NTUST) Guy, Florian, Turker, Judy, Eino, Raymond (Eurecom) Benoit (SYRTEM)

Weekly development calls Asia: Friday Odd weeks: 11:00 CEST (17:00 CST) Americas: Friday Even weeks: 14:00 CEST Reminders on mailing list

Trello task manager https://trello.com/b/hrVm1S0n/oai-5g-nr

Mailing list https://lists.eurecom.fr/sympa/info/openair5g-nr

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