Carrier Aggregation Implementation on the

OpenAirInterface Platform

Florian Kaltenberger (Eurecom)

CROWNCOM, 1.6.2016

Motivation

LTE-Advanced carrier aggregation (CA) is one of the key features to enable dynamic spectrum access

It’s also the basis for licensed assisted access (LAA) and licensed shared access (LSA)

Efficiently exploiting CA is not trivial Challenges in scheduling, load balancing, dynamic carrier

activation/deactivation Experimentation with these techniques not possible with commercial

equipment

OpenAirInterface is an open-source implementation of LTE-Advanced Extended with CA features and scheduler FAPI Allows integration and innovation of new sharing mechanisms

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OpenAirInterface today

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Introduction

OpenAirInterface Open-source implementation of 4G LTE/5G (UE, eNB, EPC) Works with popular SDR boards (ExpressMIMO, USRP, bladeRF) Allows real-time experimentation with commercial equipment

Objectives Bring academia closer to complex real-world systems Open-source tools to ensure a common R&D and prototyping

framework for rapid proof-of-concept designs

Other use cases Interoperability with 3rd party components (UE, eNB, EPC) Matlab/Octave tools for non real-time experimentation Real-time channel sounding (EMOS) 802.11p Modem System and unitary simulations

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Evolution of LTE Carrier Aggregation

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Aggregation of 32 carriers

Experimental support in OAI

Release 10 carrier aggregation features in OAI*

2 DL carriers, 1 UL carrier Feedback (ACK/NACK & CQI) for both DL carriers on UL carrier

UE can connect on either carrier

RRC (re-)configuration of secondary component carrier (SCC)

Dynamic activation and de-activation of SCC through MAC signaling

Simple round-robin scheduler No load balancing or fairness

* Available from gitlab.eurecom.fr/oai/openairinterface5g, branch feature-15-carrier-aggregation

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The Femto Application Program Interface (FAPI)

“LTE MAC Scheduler Interface Specification v1.11” published by the Femto Forum (now Small Cell Forum) in 2010

Extended in SOLDER project for carrier aggregation

Implemented in OAI*

Integrated with simple scheduler (single carrier) so far

* Available from gitlab.eurecom.fr/oai/openairinterface5g, branch feature-31-ff-scheduler-api

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IS-Wireless scheduler overview

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Main features of the advanced algorithm: Support for Carrier Aggregation –

activation and deactivation of component carriers

Ability to guarantee GBR traffic

Real-life imperfection corrections – wrong CQI reporting compensation

Multiple priority components

Parametrization (maximizing eNB throughput, fairness, minimizing latency)

IS-Wireless scheduler features

Throughput results obtained with LTE MAC Lab

See http://is-wireless.com/lte-enb-scheduler/ for details

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Demo setup

UE connects on 1 component carrier (CC) Second CC can be (de-)activated manually Throughput change can be observed via iperf

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3rd party EPC OAI eNB + ExpressMIMO2

Conclusions

New OpenAirInterface features to enable spectral agile communication (LSA, ASA, etc) Carrier aggregation FAPI for schedulers

OAI is used already in some trials and testbeds E.g. FLEX

We welcome new users and developers

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Thank you!

www.openairinterface.org

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