3GPP TSG-SA WG1 Meeting #71 ad hoc on SMARTER (5G) S1-153199

Vancouver, Canada, 19 – 21, October, 2015 (Revision of S1-153006, 3123, and 3158)

Title: Use Case and Requirements for Broadband Direct Air to Ground Communications (DA2GC)

Agenda Item: 3.5 New use cases

Source: III

Contact: Lucas Yi-Hsueh Tsai (lucas@iii.org.tw)

Abstract: <provide a short description of the content>

This paper proposes new use case and potential requirements for Broadband Direct Air to Ground

Communications (DA2GC).

Introduction

According to ITU-R M.2282-0 [1], a broadband Direct-Air-to-Ground Communications (DA2GC)

system constitutes an application for various types of telecommunication services, such as Internet

access and mobile multimedia services, during flights. The connection with the flight passengers’

user terminals on board aircraft is realized by already available mobile communication systems on

board aircraft. The main application field would be Air Passenger Communications (APC). In

addition, a broadband DA2GC system could also support Airline Administrative Communications

services (AAC) and thus improve aircraft operation, resulting, in particular, in reduced Operational

Expenditure (OPEX) for the airlines. Safety-relevant communications such as Air Traffic Control

(ATC) and related services are not intended to be covered. The 5G technology should bring the same

broadband wireless access capability for on-board network access to the airlines, and provide almost

the same experience in the air that you have at home.

Broadband Direct Air to Ground Communication

In Figure 1, the radio base stations on the ground (Terrestrial Ground Stations) are connected to a

beam-forming antenna placed on the lower fuselage of the aircrafts, transmitting data up to 100

Mbit/s while the aircraft is flying. Then the signal is distributed in the aircraft using wireless access

points. When a plane is connected to terrestrial base stations on the ground, the airplane is able to

provide its passengers with broadband Internet at up to 100 Mbit/sec. The goal is that passengers

should have better quality of experience (QoE) on an aircraft. Moreover, airlines can leverage the

network for operational applications.

Ground station

Fly over the route

Hand over

Backbone network

Link of millimeter wave communication

Figure 1 An Example of Direct Air-to-Ground Communication [1]

For DA2GC usage [1], Figure 2 depicts an experimental network architecture supporting direct Air-

to-Ground Communication. This broadband DA2GC system is based on 3GPP LTE Rel. 8+

specifications. In particular, synchronization algorithms as well as the maximum Tx power of the

On-board Unit (OBU) are to be modified compared to terrestrial mobile radio usage in order to cope

with the high Doppler frequency shift caused by aircraft speed and large cell sizes. In addition, the

Ground Station (GS) antenna adjustment has to be matched to cover typical aircraft altitudes

between 3 and 12 kilometers by adaptation of vertical diagrams including antenna up-tilt. When

commercial, this solution will be able to provide in-flight mobile voice and broadband data

communication services.

Figure 2 System architecture for the broadband DA2GC system [1]

For this system trial flights with prototype equipment [1] were successfully performed in Germany

within the 2.6 GHz FDD bands (useable only for trial, but not available for deployment of DA2GC

due to planned LTE-deployment for terrestrial cellular mobile) with a signal bandwidth of

2 × 10 MHz.

Trial set-up details (see Fig. 2):

– Two sites with an inter-site distance of about 100 km were equipped with LTE-based

DA2GC GSs consisting of baseband unit (BBU) and remote radio head (RRH) and with

antennas with three sectors (up-tilt), connected with an LTE evolved packet core (EPC)

and measurement & data trace servers via a broadband data transport network.

– An Airbus A320 aircraft was equipped with a DA2GC OBU with maximum Tx power of 37

dBm and with two DA2GC antennas below the aircraft fuselage (2 Rx/1 Tx).

Ground Station 2

SGW PGW MME PCRF

Test Center

Evolved Packet Core

OMC Measurement &Trace Servers

SGW PGW MME PCRF

Test Center

Evolved Packet Core

OMC Measurement &Trace Servers

Data

Transport

Network

Data

Transport

NetworkGround Station 1

BBU

A320 Trial AircraftDA2GC Antennas

DA2GC OBUMeasurement & Trace

Servers (incl. flight data)

LTE-basedDA2GC

Radio Links

RRH

BBU

Antenna

RRH

Antenna

Figure 3 Trial flight set-up for the broadband DA2GC system [1]

During a 3-hour trial flight [1], the aircraft flew with speeds between 500 km/h and more than

800 km/h at different altitudes between 4000 meters and 10000 meters. The flight manoeuvers

included phases with inter- and intra-site (sector) handovers as well as phases with large distances to

the sites. Trial results:

– The radio link between the GS and Aircraft Station (AS) was established at distances of

more than 100 kilometers from the sites to the aircraft flying at speeds of more than

800 km/h and altitudes up to 10000 meters.

– Peak data rates of up to 30 Mbit/s in the forward link (ground-to-air) and 17 Mbit/s in the

reverse link (air-to-ground) were achieved.

– In addition to high background data traffic, a video conference was established between the

teams in the aircraft and the test center which allowed to follow the flight phases in real time

and to demonstrate the low latency of the overall DA2GC system (round-trip time

< 50 milliseconds) compared to satellite-based systems.

It should be noted that the GS equipment used (except of antenna adjustment) was basically state-of-

the-art LTE-equipment for 2.6 GHz terrestrial cellular mobile deployment. Only the OBU was

modified to allow the overall system to work in the aeronautical environment with large cell ranges

and high aircraft speeds. The trials showed the very high performance and flexibility of the

LTE-based technology even in this early release state.

Candidate Bands in Europe for DA2GC

According to the results [2] of a CEPT questionnaire on authorization issues regarding the candidate

bands for Broadband Direct-Air-to-Ground Communications (DA2GC) in 2013, the prospects for

change of use through liberalization appear in general promising for the 2 GHz unpaired bands,

whereby the precise liberalization framework may need to be found by the individual administration.

It may be helpful to describe more in detail the options for a precise liberalization framework in

accordance with the needs of the new foreseen spectrum usages (e.g. pan-European service coverage

in case of DA2GC, or progressive introduction as licenses expire in case of PMSE) and to set up a

common European implementation schedule for future harmonized and efficient use of the 2 GHz

unpaired bands. The difficulties related to current regulations and possible options for a

liberalization framework are described in the present Report from CEPT, which details the work

undertaken and presents final results under this Mandate.

Reference

[1] Report ITU-R M.2282-0 , “Systems for public mobile communications with aircraft M Series

Mobile, radiodetermination, amateur and related satellite services”

(https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2282-2013-MSW-E.docx)

[2] Draft CEPT Report 52, “Report from CEPT to the European Commission in response to the

Mandate “To undertake studies on the harmonised technical conditions for the 1900-1920 MHz

and 2010-2025 MHz frequency bands (“Unpaired terrestrial 2 GHz bands”) in the EU””

(https://www.rtr.at/en/tk/Spectrum2100MHzTDD/29348_PC_CEPT_Rep52.pdf)

[3] S1-124017, “Mobility Consideration for Public Safety”

[4] S1-124022, “Public Safety Use Cases with UAV”

[5] S1-135024, “Use Cases and Requirements for Isolated EUTRAN Operation”

[6] RP-141862, “Mission Critical Air Ground Air Communications”

[7] RP-150315, “Mission Critical Air Ground Air Communications: Summary of email”

[8] RP-150506, “3GPP TSG RAN views regarding Mission Critical Air Ground Air”

[9] 3GPP TR 22.891 V1.0.0, “Feasibility Study on New Services and Markets Technology Enablers;

Stage 1 (Release 14)”

Proposal

The following update of the TR 22.891 v1.0.0 is proposed:

*** First Change ***

2 References

[x] Report ITU-R M.2282-0, “Systems for public mobile communications with aircraft M Series

Mobile, radiodetermination, amateur and related satellite services”

(https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-M.2282-2013-MSW-E.docx)

5.x Broadband Direct Air to Ground Communications (DA2GC)

5.x.1 Description

This use cases describes a broadband Direct-Air-to-Ground Communications (DA2GC) system

constitutes an application for various types of telecommunication services, such as voice/video call,

Internet access and mobile multimedia services, during flights.

5.x.2 Pre-conditions

A service access network infrastructure, e.g. eNB and WiFi AP (both already certified for on-board

implementation), is provided in an airplane to offer passengers in-flight mobile voice and broadband

data communication services.

During a flight, the aircraft flew with speeds between 500 km/h and up to [900 km/h] at different

altitudes between 4000 meters and 10000 meters.

5.x.3 Service flows

During the flight,

Mary wants to surf the Web;

Jason wants to make phone calls with his children;

Grace wants to participate a video conference meeting with her colleagues;

John wants watch a Full HD streaming life video of PyeongChang 2018 or Tokyo 2020 on his

tablet on his tablet.

Alice wants watch a Full HD streaming movie.

Bob wants to make a video call with his wife;

5.x.4 Post-conditions

Afterward,

Mary starts to surf the Web;

Jason initials a phone calls with his children;

Grace participates a video conference meeting;

John watches a Full HD streaming life video on his tablet.

Due to bandwidth limitation of Direct-Air-to-Ground Communications (DA2GC) system,

Alice might not be able to watch his Full HD streaming life video.

Bob might start a video call with reduced quality such as lower resolution or voice-only.

5.x.5 Potential Service Requirements

The 3GPP system shall provide Direct Air to Ground Communications (DA2GC).

5.x.6 Potential Operational Requirements

*** End of First Change ***