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Draft ETSI TR 102 892 V1.1.1_004 (2010-02)Technical Report

Electromagnetic compatibilityand Radio spectrum Matters (ERM);SRD radar equipment using WLAM

(Wideband Low Activity Mode) and operating in the frequency range from 24,05 GHz to 24,50 GHz;

System Reference Document

ETSI

Reference

DTR/ERM-TGSRR-053

Keywords radar, radio, RTTT, short range, SRD, SRDOC,

Keywords radar, radio, short range, SRD, SRDOC, WLAM

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Draft ETSI TR 102 892 V1.1.1_004 (2010-02)Draft ETSI TR 102 892v1.1.1_003 (2010-02)2

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Contents

Intellectual Property Rights..............................................................................................................................6

Foreword...........................................................................................................................................................6

Introduction......................................................................................................................................................6Status of the pre-approval draft.........................................................................................................................................6

1 Scope......................................................................................................................................................7

2 References..............................................................................................................................................72.1 Informative references......................................................................................................................................8

3 Definitions, symbols and abbreviations.................................................................................................93.1 Definitions........................................................................................................................................................93.2 Symbols............................................................................................................................................................93.3 Abbreviations....................................................................................................................................................9

4 Comments on the System Reference Document..................................................................................10

5 ......................................................................................................................................................................................................................................................................................................................................................................................................................................................................Executive summary..............................................................................................................................................................10

5.1 Background information.................................................................................................................................105.1.1 The current situation.................................................................................................................................105.1.2 The socio-economic benefits.....................................................................................................................115.2 Technical information...............................................................................................................................125.3 Market information...................................................................................................................................13

6 Radio Spectrum requirements and justification...................................................................................15

7 Current regulations...............................................................................................................................15

8 Proposed Regulation............................................................................................................................16

9 Main conclusions..................................................................................................................................16

10 Requested ECC and EC actions...........................................................................................................17

11 Expected ETSI actions.........................................................................................................................17

Annex A: Detailed market information......................................................................................................18

A.1 Applications.........................................................................................................................................18

A.2 Market..................................................................................................................................................22A.2.1 WLAM activation strategy.............................................................................................................................22

Annex B: Technical information.................................................................................................................25

B.1 Technical description...........................................................................................................................25B.1.1 ............................................................................................................................24GHz-NB systems overview

........................................................................................................................................................................25B.1.2 ....................................................................Design considerations to go from 24GHz-NB to WLAM systems

........................................................................................................................................................................25B.1.3 ................................................................................................................Overall WLAM activation conditions

........................................................................................................................................................................27

B.2 Technical justifications for spectrum...................................................................................................28B.2.1 Power issues....................................................................................................................................................28B.2.2 Frequency issues.............................................................................................................................................32B.2.3 WLAM activity Factor....................................................................................................................................33B.2.3.1- Activation conditions of the WLAM mode.......................................................................................................34

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B.2.3.2 Controllability of the WLAM mode.........................................................................................................34B.2.3.3 Scenario 1: Active Safety Mode...............................................................................................................34B.2.3.4 Scenario 2: Urban and Rural Parking mode..............................................................................................35B.2.3.5- Scenario 3: High Density Parking Mode...........................................................................................................36Car shielding 37B.2.3.6- Overall activity factor for the WLAM mode.....................................................................................................38B.2.3.7 Statistics about Travel Duration..........................................................................................................................40B.2.3.8 Crash Alert Occurence..............................................................................................................................41B.2.3.9 Parking structures Design Rules.........................................................................................................................42B.2.3.10 Rear Parking Manoeuvre Durations..........................................................................................................44

B.3 Information on performance benchmarking with other short range radar solutions............................45

Annex C: Expected compatibility issues.....................................................................................................45

C.1 Existing allocations..............................................................................................................................45

C.2 Coexistence and sharing issues............................................................................................................46C.2.1 Scenario with WLAM in calibration mode...............................................................................................47C.2.2 Temporary fixed receiver versus WLAM for pedestrian detection.......................................................................51

History............................................................................................................................................................55

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Intellectual Property RightsIPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://webapp.etsi.org/IPR/home.asp).

Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document.

ForewordThis Technical Report (TR) has been produced by ETSI Technical Committee Electromagnetic compatibility and Radio spectrum Matters (ERM).

The present document includes necessary information to support the co-operation under the MoU between ETSI and the Electronic Communications Committee (ECC) of the European Conference of Postal and Telecommunications Administrations (CEPT).

IntroductionThe European Commission has issued a new Mandate [i.4] to the ECC related to automotive Short Range Radars (SRR), whose purpose is divided in two different parts. Part 1 of the Mandate is linked to the fundamental review as defined in EC Decision 2005/50/EC [i.1] related to the harmonization of the 24 GHz range radio spectrum band for the time-limited use by automotive short-range radar equipment in the community.

According to Part 2, this mandate also requires studies regarding alternative solutions for radar-based road-safety applications. An open question raised is on:

“CEPT is mandated to, where any alternative bands are to be considered for automotive short-range radar systems, propose appropriate technical and regulatory measures to ensure the protection of existing radio services in or near any such bands.”

ECC WGFM has requested ETSI TC ERM to create an ETSI System Reference document on WLAM. ERM#39 adopted a new work item for the creation of such an ETSI system reference document. The present document is intended to deliver the technical characteristics necessary to describe the spectrum needs, the expected usage scenario and technical performance and implementation aspects for 24 GHz WLAM Mode equipment. In addition, related market information is provided.

Status of the pre-approval draftThe present document has been created and agreed by TC-ERM TG SRR. Final approval for publication as ETSI Technical Report is expected to be performed via approval by correspondence by mid of March 2010 according to the ETSI work item DTR/ERM-TGSRR-053.

The present draft document is now intended for submission to ECC/WGFM and ECC/WGSE and the EC for their information and consideration at their next meetings (Draft system reference document stage 1). In parallel, the ETSI internal correspondence procedure should be started.

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http://webapp.etsi.org/IPR/home.asp

Target version Pre-approval date version(see note)

V1.1.1 A s m Date DescriptionV1.1.1 0.0.1 December 30th ,

2009Rapporteur`s draft for consideration in ERM TG SRR

V1.1.1 0.0.2 1st February 2010 2nd draft from rapporteur with some comments incorporated from eTSi members.

V1.1.1 0.0.3 4th February 2010 Review Josef SchuermannV1.1.1 0.0.4 9th February 2010 c Check by the rapporteur

1 ScopeThe present document provides information on short range device equipment using the Wideband Low Activity Mode (WLAM) and operating in the frequency range from 24,05 GHz to 24, 50 GHz. The WLAM mode is used in certain circumstances. The primary application focus is pedestrian detection and protection. Other usage scenarios do include specific driving situations such as parking mode. It provides an improved performance compared with narrowband radars operating totally within the ISM frequency range from 24,05 GHz to 24,25 GHz by activating a larger bandwidth from 24,05 GHz to 24,50 GHz.

The narrowband radar can switch from the “ISM-only mode” to the WLAM by applying a periodic calibration operation.

Note: the narrowband radar (24,05 GHz to 24,25 GHz)is already included in ERC Recommendation 70-03, Annex 5 [i.14] with a maximum allowed radiated power of 100 mW e.i.r.p..

The automatic switching between the “ISM mode” and the WLAM is initiated by additional sensors such as a front camera for detection of pedestrians in the vehicle path, the usage of the reverse gear (parking situation) or active braking in order to complement passive protection of the driver and passengers for vehicle speeds up to 40 km/h.

Consequently, the usage activity factor of the WLAM is limited, typically in the range of less than 1% of the time when the vehicle is in use.

The present document includes the necessary information to support the co-operation between ETSI and the ECC including:

Detailed market information (annex A)

Technical information (annex B)

Expected compatibility issues (annex C)

2 ReferencesReferences are either specific (identified by date of publication and/or edition number or version number) or non-specific.

For a specific reference, subsequent revisions do not apply.

Non-specific reference may be made only to a complete document or a part thereof and only in the following cases:

o if it is accepted that it will be possible to use all future changes of the referenced document for the purposes of the referring document;

o for informative references.

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Referenced documents, which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference.

NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long-term validity.

2.1 Informative references[i.1] 2005/50/EC: Commission Decision of 17 January 2005 on the harmonisation of the 24 GHz range

radio spectrum band for the time-limited use by automotive short-range radar equipment in the Community (notified under document number C(2005)34 - Text with EEA relevance).

[i.2] CEPT ECC/DEC/(04)10: ECC Decision of 12 November 2004 on the frequency bands to be designated for the temporary introduction of Automotive Short Range Radars (SRR) (2004/545/EC) and (2005/50/EC) amended 5 September 2007.

[i.3] CEPT ECC/DEC/(04)03: ECC Decision of 19 March 2004 on the frequency band 77-81 GHz to be designated for the use of Automotive Short Range Radars.

[i.4] 2nd Mandate of the European Commission on SRR (document RSCOM08-81 Final of 7 November 2008)

[i.5] Draft CEPT Report 36: Report from CEPT to the European Commission in response to Part 1 of the Mandate on Short Range Radar

[i.6] COMMISSION DECISION of 8 July 2004 on the harmonisation of radio spectrum in the 79GHz range for the use of automotive short-range radar equipment in the Community (notified under document number C(2004)2591 (Text with EEA relevance) (2004/545/EC)

[i.7] CEPT/ERC/Recommendation 74-01E: "Unwanted Emissions in the Spurious Domain".

[i.8] ERC Report 25: "The European table of frequency allocations and utilizations in the frequency range 9 kHz to 3000 GHz".

[i.9] ITU Radio Regulations.

[i.10] ECC-ETSI MoU (version of April 2004).

[i.11] RSPG Opinion on "Streamlining the regulatory environment for the use of spectrum", document RSPG 08-246.

[i.12] CEPT/ERC/Recommendation (02)05: "Unwanted Emissions".

[i.13] EG 201 788 (V1.2.1): "Electromagnetic compatibility and Radio spectrum Matters (ERM); Guidance for drafting an ETSI System Reference Document".

[i.14] CEPT/ERC/Recommendation 70-03: “Relating to the use of Short Range Devices (SRD)”.

[i.15] ETSI TR 102 664: Electromagnetic compatibility and Radio spectrum Matters (ERM); Road Transport and Traffic Telematics (RTTT); Short range radar to be used in the 24 GHz to 29 GHz band; System Reference document for 26 GHz UWB SRR

[i.16] COMMISSION DECISION of 13 May 2009 amending Decision 2006/771/EC on harmonisation of the radio spectrum for use by short-range devices (notified under document number C(2009) 3710) (Text with EEA relevance) (2009/381/EC)

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http://docbox.etsi.org/Reference

3 Definitions, symbols and abbreviations

3.1 DefinitionsFor the purposes of the present document, the following terms and definitions apply:

bandwidth: range of frequencies, expressed in Hertz (Hz), that can pass over a given transmission channel

frequency allocation (of a frequency band): entry in the Table of Frequency Allocations of a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions

Industrial Scientific and Medical bands (ISM): frequency bands in which non-radio RF emissions can be allocated

Narrowband (NB): classification for the spectral width of a transmission system

occupied bandwidth: bandwidth of an emission defined as 10 dB bandwidth of the power spectral density

Power Spectral Density (dBm/Hz) (PSD): Some limit specifications prefer a definition of PSD as a power in a certain

resolution: degree to which a measurement can be determined is called the resolution of the measurement

separation: capability to discriminate two different events (e.g. two frequencies in spectrum or two targets over range)

Spread Spectrum: techniques are methods by which electromagnetic energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.

ultra wideband: classification for the spectral width of a transmission system

wideband: classification for the spectral width of a transmission system

3.2 SymbolsFor the purposes of the present document, the following symbols apply:

R Range separationdBm Decibel, milliwatt f FrequencyP PowerR Distance

3.3 AbbreviationsFor the purposes of the present document, the following abbreviations apply:

ACC Automotive Cruise Control(APPS).ECC Electronic Communications CommitteeERO European Radiocommunications CommitteeFCC Federal Communications CommissionFMCW Frequency Modulated Continuous WaveISM Industrial Scientific, MedicalLRR Long Range RadarMRR Mid Range RadarRF Radio FrequencySRD Short Range DeviceSRR Short Range RadarUWB UltraWideBandWLAM Wideband Low Activity ModeBSD, LCA, FCWNOK

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http://en.wikipedia.org/wiki/Signal_(electrical_engineering)

http://en.wikipedia.org/wiki/Frequency_domain

http://en.wikipedia.org/wiki/Bandwidth_(signal_processing)

http://en.wikipedia.org/wiki/Electromagnetic_radiation

4 Comments on the System Reference DocumentThe present document has not undergone any ETSI internal consultation yet. Therefore, it has not received any comments yet.

5 Executive summary

5.1 Background information

5.1.1 The current situationIn 2004 and 2005, two frequency bands were identified for the introduction of automotive UWB SRR (Short Range Radar) technology in Europe [i.1, i.2, i.3, i.6]:

the 24 GHz frequency range (i.e. 21,65 GHz to 26.65 GHz), as a temporary band for UWB SRR systems (24 GHz UWB SRR)

the 79 GHz frequency range (i.e. 77 GHz to 81 GHz), as a permanent band for UWB SRR systems (79 GHz UWB SRR)

The European frequency regulation currently requires UWB SRR to migrate from 24 GHz to 79 GHz spectrum in the year 2013.

Decision 2005/50/EC [i.1] on the 24 GHz frequency range stipulates that a fundamental review of the Decision should be carried out by 31 December 2009.

Draft CEPT Report 36 [i.5] was approved, subject to public consultation, by the ECC at its meeting in October 2009 in response to Part 1 of the EC mandate on SRR ("SRR Mandate 2"). It concludes in particular the following:

- existing regulation for UWB SRR in the 24 GHz frequency range should not be modified;

- while the semiconductor technology for 79 GHz is now available, system integration and validation of 79 GHz UWB products may not be possible in time for a seamless transition in 2013.

The assessment of the automotive short range radars falls within Part 2 of the new EC Mandate on SRR and aims to consider the possibility to allow alternative bands for SRR systems. It has been developed by WGFM Project Team FM47 on UWB in parallel with relevant compatibility studies performed within WGSE Project Team SE24.

The inclusion of WLAM compatibility study in the SRR-Mandate 2 was supported by WG-FM:

“WG-FM also encourages the compatibility analysis to be developed on a technology neutral basis so as to address various technological approaches foreseen within the automotive industry in this frequency range for implementing road-safety applications” - liaison statement WG-FM to WG-SE, dated February 13,2009

As a consequence the compatibility study is being performed by SE24, and it was decided to start an SRDoc in parallel.

The recent and successful deployment of the 24GHz-NB (Narrow-Band) radar technology has shown this technology:

Can address many of the short and mid range driving assistance and road safety features with a 200 MHz bandwidth: the first launch was related to rear applications (Blind Spot Detection & Lane Change Assist in 2006/7), followed by front applications (Front Collision Warning in 2009). A 120m range ACC with Stop & Go and automatic braking capabilities was recently announced, as ready to go in production in 2013..

Will get an harmonized standard EN 302 858 in Europe in 2010: Implementation starting after the validation of WG-FM of an update of Annex 5 (RTTT) of ERC Recommendation 70-03 [i.14].

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Can be implemented all over the world, based on the ITU recommendation related to Short Range Devices in the category “detection of movement and alert”.

Can be implemented primarily on low and middle class cars

Will generate significant sales (>1 Mu/y expected next year) which will support quick cost reductions and speed-up the safety feature deployment: new low-cost sensors are expected in the 2012-2013 time-frame

5.1.2 The socio-economic benefitsThe European Union’s eSafety Initiative in 2003 established the goal to reduce the number of road fatalities by 50% up to the year 2010. There are over 40,000 fatalities on the roads every year in the EU member states, resulting from 1.4 million accidents, with an equivalent cost of around €200bn/year, or 2% of EU GDP.

Road safety policies can rely on various initiatives, including SRR, which is described in ETSI TR 102 664 [i.15] as an enabling technology for enhanced active safety systems e.g. the mitigation of rear-end crashes which will reduce damages and saving of lives.

According to some accident studies referred to in ETSI TR 102 664, rear-end collisions dominate in collision statistics. For example in Germany, there are over 50,000 severe rear-end accidents every year, with 5,700 death cases or serious injuries. In the U.S., around 30 percent of all traffic accidents are the result of rear-end collisions. Reducing these accidents by 20 percent and additionally reducing the severity of an even higher percentage, would be a milestone in improving automotive safety.

The socio-economic benefit is related to the reduction of pedestrian injury severity as shown in figue 1 below. More detailed information is found in annex A, clause A.2.

Figure 1: Reduction of pedestrian injury severity (Source: Valeo)

- The analysis of accidents with pedestrian (France 2008) show most of the fatalities happen:o In urban areas (70%)o When the pedestrian is crossing the road (70%)o On the pedestrian cross-path or closer than 50m from the cross-path (70%)o At a speed estimated above 40kph (70%)

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5.2 Technical information WLAM systems will have the flexibility to operate with an increased bandwidth of 450 MHz (200 MHz in the

standard mode) and a low activity factor for specific driving situations, to improve the detections in critical environments when the separation of targets is difficult (i.e. Pedestrian Detection support in parking lots)

There are two 24GHz NB technologies already on the market since 2006 and 2007:

24GHz NB radars with fixed beams 24GHz NB multi-beam radars with scanning beams

The following table 1 shows a summary of the WLAM and 24 GHz NB radar technology. more details are given in annex B.

Table 1: Summary of technologies

SPECIFICATIONS 24GHz NBFixed-Beam(s) Tx

24GHz NBMulti-Beam Tx

Comments

A- STANDARD ISM MODEBandwidth in standard Mode GHzMax eirp Standard Mode

24,05-24,2520 dBm

24,05-24,2520 dBm

Existing frequency designation

Regulation appylingERC REC 70-03,Annex6

ETSI 300-440/EN 302 858ERC REC 70-03,Annex6

ETSI 300-440/EN 302 858

B- WLAM / Low Activity ModeBandwidth in GHz 24,05-24,50 24,05-24,50 Extended Bandwidth

Max eirp 20 dBm 20 dBm consistent with existing 24GHz NB

Activity factor at 20dBm eirp < 1% < 1% Estimate - see conditions of operation

Modulation LFMSK or FMCW LFMSK or FMCW consistent with existing 24GHz NB

Police Radar Mitigation Factor applying within the 24,075-24,15GHz band(Dwell Time restrictions)

4 µs/40 kHz dwell time every 3 ms Or 1 ms/40 kHz Dwell Time every 40 ms

4 µs/40 kHz dwell time every 3 ms Or 1 ms/40 kHz Dwell

time every 40 ms

consistent with the new harmonized standard for existing 24GHz NB / EN 302 858

EESS protection level TBD TBD To be consistent with SRRs

Antenna 10dB Beam-width in Azimuth < 40° max < 35° max

Antenna Pattern in ElevationAngle above horizontal

At +20° elev: -10dBAt +25° elev: -20dB> +25° elev: -23dB avge

At +20° elev: -10dBAt +25° elev: -20dB> +25° elev: -23dB avg

-

Antenna Gain > 6dBi about 6dBi f (beam) for multi-beam

Duty Cycle – Power ON 100% max 100% max -

Number of radars per cars (Typical) 2 rears1 front

2 rears1 front

some premium cars might have 2 front radars

Number of radars simultaneously activated in a 50MHz band / WLAM mode

1 1 Non synchronizedemissions

Mounting Position / 2 rear radars rear bumper, deltapointing angle > 40°

+height of about 50cm

rear bumper, deltapointing angle > 40°

+height of about 50cm

-

Percentage of cars equipped up to 100% penetration rate up to 100% penetration

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rate

5.3 Market information

5.3.1 Industry stakeholders

The concept called WLAM / “Wideband Low Activity Mode” to improve the existing technology was proposed by the industry supplying the existing 24 GHz-NB radar technology, capable of short range and mid range features.

VALEO, HELLA/SMS, Autoliv, Continental and TRW are known equipment makers offering NB-24GHz systems.

5.3.2 24 GHz-NB radar applications

The 24GHz-NB radar technology is mainly used for rear applications and can cover many applications such as Blind Spot Detection, Lane Change Assist, Rear Pre-crash, Cross Traffic Alert. The introduction of this technology for front applications is just starting, and will be limited to short/mid range applications (no ACC long range) and with limited resolution as compared to UWB SRRs.

The 24GHz-NB radar technology cannot cover Parking Aid due to a limited bandwidth. Parking is not a priority function for radars since the ultrasonic technology is standard and much lower in cost. However, the WLAM concept is also a way to improve the existing 24GHz-NB technology, to improve the detection of objects in critical driving situations, i.e. pedestrian detection in parking lots.

According to VALEO and SMS,NB-24 GHz REAR type applications are used in:

- Blind Spot Detection (10m warning) in production;- Cross Traffic Alert (25m warning) in production;- Lane Change Assist (70m warning) in production;- Rear Pre-Crash (60m range) in production.

NB-24 GHz FRONT applications are predicted for the 2010-2013 time-frame to the market:

- Forward Collision warning (100m+) in production;- Front pre-crash & automatic braking;- Low-cost ACC zero speed up to 130km/h.

The 24GHz NB radar technology has achieved a reliable performance in complex environments for BSD, LCA, FCW (available in city) and CTA (parking environment).

According to market figures, 24 GHz NB radars are now increasingly used in the automotive market since they can realize most of the driving assistance features (range up to 150m). This should be balanced in case of ACC as the medium range offered by 24 GHz NB radar would not be suited for highway scenarios.

It is also to be noted that narrow band radars (typical bandwidth 100 MHz) are limited in applications because of their limited local resolution and therefore limited capability of object separation or of object tracking (discussed further below). Today, narrowband applications on the road are constrained to a reduced set of safety functions such as Blind Spot Detection (objects in the blind spot of the mirror) and Lane Change Assistance.

There are classes of real world scenarios that cannot be addressed by 24 GHz NB radar systems. A real world scenario is typically a pedestrian emerging from between two parked vehicles. Spacing between parked vehicles is often on the order (or less) than 24 GHz NB resolution capability, thus the NB radar would be unable to identify sufficiently a pedestrian location as compared to wideband radar systems.

The 24GHz-NB radar technology has significantly lower cost than the 77GHz technology, which means that the 24GHz-NB radar technology has a high growth rate and is being implemented on middle and family cars.

5.3.3 Availability of 24 GHz-NB radar and WLAM applications

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24GHz NB radars are already in production for front & rear applications; they can address also the mid-range applications since the 24 GHz technology has a lower cost reduction potential. This makes this technology attractive to the vehicle manufacturers, prototypes have shown a high capability to include safety features with a good performance.

The limitations specific to a 200 MHz bandwidth can be noticed in critical environment – like parking, pedestrian detection limitations which can be solved by a increase of the bandwidth operating at a low activity factor and reduces the interference risk with existing services.

The 30cm object resolution of the 450MHz WLAM mode will be similar to the a resolution of 77GHz ACC and pre-crash systems (e.g. bandwidth < 500 MHz used in Japan). The combination of WLAM sensors with ultrasonic sensors will allow a enhanced resolution in the very short range, and can be used for pedestrian detection in city and parking conditions however the resolution in critical situations is below the capability of UWB SRRs.

24GHz NB Radars found a successful market using the current GaAs technology, market growth will increase once the cheaper SiGe technology is introduced around 2013 time frame.

The success of 24 GHz NB radars can be first explained by its availability allowing gradual implementation of some driving assistance and road safety applications in cars. Some industry suppliers have announced ACC Stop&Go with pre-crash applications in production foreseen for 2013. These radar based systems would fit the proposed EU regulation to mandate automatic emergency braking systems for medium and heavy commercial vehicles from 2013 onwards.

5.3.4 Worldwide regulatory environment for 24 GHz NB and WLAM mode

The regulatory environment of 24 GHz NB radar is primarily given by Footnote 5.150 of the Radio Regulations (ISM applications) and therefore has the potential for worldwide implementation. 24GHz NB-radar technology with a 200 MHz bandwidth and a 20dBm peak which has been approved in USA, Canada, Brazil, EU, China/Taiwan, Korea, Russia and Ukraine. The 200 MHz band is under study in Japan where only a 76 MHz bandwidth is currently permitted.

The regulatory situation for the extended range WLAM in the ITU and for global harmonization is critical since the range from 24,250 GHz to 24,50 GHz is outside the ISM band and critical for compatibility to other services considering the level of +20 dBm. To facilitate the compatibility a activity factor of 0.5 % is proposed. Individual compatibility studies in the various countries for harmonization are needed.

5.3.5 Production volumes

The production of 24GHz-NB radars are projected for over 1Mu/y by end 2010 mainly for rear applications

By end of 2013, the production is anticipated to exceed 3Mu/y

After 2013, the deployment of front applications and low-cost radars will enhance the growth

5.3.6 Outlook

The implementation of the WLAM mode with an extended frequency range of 24,05 GHz to 24,50 GHz will remedy to some limitations encountered by the 24GHz-NB radars in certain driving conditions, with a primary focus on pedestrian detection.

The key-benefits are:

The improvement of an existing radar 24 GHZ NB radar standard technology which has a worldwide frequency allocation.

To complement the existing detection devices supporting pedestrian detection (ultrasonic sensors), by using the radars already available on the car to improve field of view and detection range

Benefit from the relatively high power of the 24GHz-NB radars over a larger bandwidth, to better discriminate pedestrian in parking or city environments

Get an easy and immediate safety benefit due to the large deployment of the 24GHz-NB technology

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Get an easy and quick implementation with a limited on-cost for the car-makers

Critical factors are:

Some industry stakeholders believe that there are indeed some limitations compared to 77/79GHz systems, mainly on the range resolution and the detection range. Proposed enhancement of this technology (WLAM) to address some critical “pedestrian protection” scenarios would still leave some long range features and some specific safety scenarios uncovered. For example, 24 GHz NB radars are likely to be less effective in dealing with accident situations involving a single vehicle and a stationary object.

The 24 GHz NB radar improvement by the extension range beyond the ISM band limits creates a new situation and challenge for global harmonization and compatibility studies in many countries are needed for effective worldwide deployment of the extension range.

For a one-to-one comparison 24 GHz NB radar to UWB SRR the object resolution is lower.

For a given set of safety functions or applications (see Fig. A1), several NB modules versus one UWB module or sensor needed to cover a similar set of functions.

6 Radio Spectrum requirements and justificationThe benefits of improving the current 24GHz-NB technology are the following

Many car-makers are already in production with 24 GHz NB radar especially in EU Any improvement (with extended range) will have an immediate benefit to the road safety, because it is an available technology.

WLAM is a minor product change, and will use the same signal processing and transmitting power as today: it can be implemented with low re-validation costs (no investment required in a new technology) and can be adopted by all the current customers depending on the national regulations.

WLAM is a focused improvement of the 24GHz-NB technology which has a permanent frequency designation, and is in line with the European frequency allocation strategy

WLAM will not impact the deployment of UWB-79GHz which will first contribute to improve the detection capability of 77GHz-ACC long range radars: the 24GHz-NB technology cannot replace 77 GHz long range ACC.

WLAM is not expected to generate any significant compatibility issues, since the potential victims in the 24,25 GHZ to 24,50 GHz band will not likely get any outdoor deployment (e.g. SAP-SAB links will not be used for outdoor applications at 24 GHz) and SAP-SAB equipments are unidirectional equipment

24GHz-NB automotive radars equipped with a WLAM mode can offer a “practical approach” to improve the 24GHz-NB radars for collision mitigation applications in order to support the EU policy goals.

7 Current regulationsThe “ISM mode” operating in the frequency range from 24,05 to 24,25GHz is covered by the following existing regulations, i.e. Europe: ERC Recommendation 70-03, Annex 5. The frequency band may also be covered by the amendment of EC Decision on SRDs 2006/771/EC [i.16] in the future.

Other international frequency regulations are given in A2.3

ETSI


8 Proposed RegulationThe proposed regulation is related to a supplementary mode to be used by the 24GHz-NB radars with a low-activity factor: in certain driving situations, the bandwidth will be extended from 200 MHz (ISM Mode) to 450MHz (WLAM Mode),

The bandwidth used will be 24,05 GHz to 24,50 GHz, the maximum e.i.r.p will be 20 dBm as in the ISM mode.

The unwanted emissions in the frequency band 23.6 GHz to 24 GHz are proposed to not exceed – 73 dBm/MHz e.i.r.p, including the activity factor.

For the unwanted emissions in the frequency band above 24,5GHz, see clause B.2.1.

9 Main conclusions The European Union’s eSafety Initiative in 2003 established the goal to reduce the number of road fatalities by 50% up to the year 2010. There are over 40,000 fatalities on the roads of the EU member states every year, resulting from 1.4 million accidents, with an equivalent cost of around €200bn/year, or 2% of EU GDP.

Road safety policies can rely on various initiatives, including SRR, which is described in ETSI TR 102 664 as an enabling technology for enhanced active safety systems e.g. the mitigation of rear-end crashes which will reduce damages and saving of lives.

According to some accident studies referred to in ETSI TR 102 664 [i.15], rear-end collisions dominate in collision statistics. For example in Germany, there are over 50,000 severe rear-end accidents every year, with 5,700 death cases or serious injuries. In the U.S., around 30 percent of all traffic accidents are the result of rear-end collisions. Reducing these accidents by 20 percent and additionally reducing the severity of an even higher percentage, would be a milestone in improving automotive safety.

The impact assessment, carried out by the CEPT as part of the response to the Mandate of the EC, does not intend to compare the merits of SRR or alternative technologies with other road safety policy initiatives. It rather concentrates (a) on possible regulatory measures to facilitate the development of active safety systems enabling the mitigation and the avoidance of collision and (b) on the assessment of the impact of these systems.

Different regulatory options need to be identified and analysed to achieve the policy objective:

WLAM is therefore seen as being complementary to existing regulations for automotive radar applications. This regulatory solution does not compete with long range solutions which can be addressed by 77/79 GHz. The addition of the WLAM extension mode l minimize the investment required.The present doc describes the need for an improvement of the existing 24GHz-NB automotive radars.

1. The 24GHz-NB technology has been successfully deployed since it covers most of the short / mid-range driving assistance and safety features required to the front and rear of the car, based on a 200 MHz bandwidth;

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2. Many car-makers have invested in the 24GHz-NB technology which is in line with the frequency allocation strategy defined by the CEPT and European Commission

3. The WLAM mode will improve the 24GHz-NB technology in specific driving situations, where a larger bandwidth is required to discriminate specific targets such as pedestrians in parking lots or cities

4. The WLAM mode is not seen to impact the fixed services implemented between 24,5GHz and 26,5GHz

5. The WLAM mode is expected to comply with the protection of the passive services between 23,6 GHz to 24 GHz;

6. The WLAM mode is using a bandwidth also designated for SAP/SAB temporary applications, which are unidirectional fixed links

7. The extended range technology is available. A short term safety benefit can be achieved at a limited add-on cost.

10 Requested ECC and EC actionsThe inclusion of WLAM compatibility study in the SRR-Mandate 2 was supported by WG-FM:

“WG-FM also encourages the compatibility analysis to be developed on a technology neutral basis so as to address various technological approaches foreseen within the automotive industry in this frequency range for implementing road-safety applications” - liaison statement WG-FM to WG-SE, dated February 13,2009

As a consequence, the compatibility study is being performed by SE24, and it was decided to start an SRDoc in parallel

ECC working group FM is requested to take into account the present document when finalizing their consideration under the SRR mandate.

Furthermore, radio compatibility and sharing studies for the verification of potential interference to other services/applications operating in the proposed band are considered to be needed (pursued by the SE24).

The EC is requested to study the proposal which may lead to the revision of the harmonized standard related to 24 GHz-NB radars (RTTT-annex 5).

ECC is requested to complete their studies by May 2010. If the studies show that coexistence with the other relevant radio services / applications can be achieved, ECC is requested to designate the band 24,05 GHz to 24,50 GHz for WLAM on an optional basis (e.g. as an alternative solution to 26 GHz UWB SRR).

The future review of spectrum regulations for automotive radar applications would actually benefit from broader view of the effective deployment of collision mitigation and avoidance applications on road vehicles and of the technologies used to implement these technologies. It would be more appropriate for such monitoring measures to be conducted by the relevant EC body in charge of coordinating road safety policies at EU level, presumably in close co-operation with the ACEA.

11 Expected ETSI actionsETSI is requested to communicate this SRDoc to the ECC and EC and publish the present document.

ETSI will also be requested to provide a revision of the 24GHz-NB harmonized standard for the proposed new frequency range.

ETSI


Annex A:Detailed market information

A.1 ApplicationsAn overview and summary on the application is provided under clause 5.3. The following maturity matrix (table A.1-1) and figure A.1-1, for the technologies in line with the existing frequency allocation strategy shows WLAM in the context with other competing technology solutions.

Table A.1-1: Maturity matrix

Features 77GHz 77GHz

+ 79GHz24GHz-NB 24GHz-NB

+WLAM

Adaptive Cruise Control 200m Long Range

PROD A-SAMPLES 2012

NOK NOK

Adaptive Cruise Control 100m Mid Range

See-long range A-SAMPLES 2012

READY for serial dev


Front Collision Warning 100m PROD A-SAMPLES 2012

PROD PROD

Front Stop & Go and automatic braking 60m

PROD (starting 2010)

A-SAMPLES 2012



Front Pedestrian Detection support

PROD (starting 2010)

A-SAMPLES 2012

NOK READY for serial dev

Rear Blind Spot Detection 10m NOK integration+cost

TBC integration+cost

PROD PROD

Rear Lane Change assist 70m NOK integration+cost


PROD PROD

Rear Pre-Crash 30 to 60m PROD expensive


SERIAL DEV (starting < 2013)

SERIAL DEV (starting < 2013)

Rear Ped. Detection support NOK integration+cost


NOK READY for serial dev

Rear Parking Aid 4-6m NOK TBC integration+cost

NOK NOK

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Figure A.1-1: Short / Mid / Long Range Radar Applications and Functions

Notes:

- No competitive information for these applications such as roadmaps is disclosed, so only information on the current availability on the market is enclosed. Car makers presently offering to the customer an application are indicated with a star in the table.

- According to car class or car line respectively performance requirements for each application can vary.- This summary is base on the replies to the questionnaire and does not provide a complete picture as not all companies

replied.

Applications This table contains the list of potential applications for short range radars. To be able to evaluate the benefits attached to each option of the Assessment, it is necessary to analyse whether the applications are supported in the case of each option.

The table below is based on the answers to the questionnaire on SRR issued by WGFM in May 2009, in particular answers to question b) [b) Which single technology (e.g. type of radar and frequency band) or combination of such technologies provides the safety/assistance feature?].

Note: where a vehicle manufacturer is marked an asterisk (*), it indicates that the application is in production.

Pedestrian protection (Active)

Active pedestrian protection (active braking/brake assist)

PSA: radar multi-beam working within 24 GHz NB or 77 GHz NB (79 GHz)

Valeo: data fusion between vision and ultrasonic for short range, extended range possible with NB 24 GHz radar if WLAM gets approval.

JLR: 24 GHz narrow band for detection (+camera to classify pedestrians)

Pedestrian protection (Passive)

Passive pedestrian protection (e.g. activation of airbags in the bumper, lifting the hood of the car etc.)

Valeo: data fusion between vision and ultrasonic for short range, extended range possible with NB 24 GHz radar if WLAM gets approval.

Pre-crash

(passive safety)

Passenger protection (air bag arming,…)

Not applicable

Collision mitigation/avoidance

(active safety)

Emergency braking


Valeo: RFQ on-going for NB 24 GHz radar systems based on low-cost ACC

Braking assistance see emergency braking

Collision warning Emergency warning (front)


ETSI


Valeo: NB 24 GHz in production

Emergency warning (rear closing vehicle)


Valeo: SOP planned before 2013 for rear pre-crash with NB 24 GHz LCA radars

Emergency warning (cross traffic)



General motors: 24-29 GHz UWB SRR or 24 GHz Narrowband MRR

JLR: 24 GHz Narrow band

Lane change assist BMW*: the system monitors the area on the neighbour lane and warns the driver if the lane is occupied (radar 24 GHz ISM)



General motors: 24-29 GHz UWB SRR or 24 GHz Narrowband MRR

JLR: 24 GHz narrow band

Blind spot detection

BMW*: see lane change assist



General motors*: 24-29 GHz UWB SRR or 24 GHz Narrowband MRR*

JLR*: 24 GHz narrow band

ETSI


Driving assistance

Adaptive Cruise control

Bosch: LRR (76-77 GHz)

Daimler*: used sensor LRR (76-77 GHz)

Continental: currently offers the 3rd generation of adaptive cruise control, based on 76-77 GHz technology

BMW*: today 76-77 GHz radar is used

Autoliv: LRR

PSA: radar multi rays working within 77 NB -81 GHz (79 GHz)

Valeo: Several NB 24 GHz suppliers are proposing low cost ACC to start serial development now

General Motors*: 76-77 GHz LRR

JLR*: 77 GHz

ACC Stop and Go Bosch: LRR (76-77 GHz) combined with other satellite sensors

Daimler*: fusion of sensor data LRR (76-77 GHz) and UWB SRR (24 or 26 GHz) and camera (planned)

Continental: stop and go function needs UWB technologies for full functionality.

BMW*: today 76 GHz and 24 GHz UWB radar is used

Autoliv: LRR in combination with UWB radar, early detection of a cut in (e.g. pedestrian or motorcyclist) requires UWB sensors.

PSA: radar multi rays working within 77 NB -81 GHz (79 GHz)

Valeo: RFQ on-going for NB 24 GHz radar systems based on low-cost ACC, (TRW proposes a 24 GHz based radar device that enables stop and go ACC).

General motors: 76-77 GHz LRR

JLR: 77 GHz wide field of view or 77 GHz narrow field of view with 24 GHz

Parking assistance

Parking Assistance

Bosch: ultrasonic sensors

Daimler*: currently ultrasonic sensors are used in a majority of cases (if radar is used 24 GHz UWB SRR)

Continental: parking applications (if based on radar) need UWB technology

BMW: ultra sonic sensors

Autoliv: UWB sensors

PSA: no need of radar

Valeo: Parking assistance has become a quasi-standard feature with ultrasonic sensors (radar is too expensive to be a standard feature and does not bring any

ETSI


advantage)

General motors*: Ultrasonic and/or 24-29 GHz SRR.

JLR*: ultrasonic sensors only

Other?

A.2 Market The market overview and market penetration expectations are summarized in clause 5.3.

A.2.1 WLAM activation strategyThe WLAM activation strategy has been defined and reviewed by the following companies: Smart Microwawe Sensors GmbH, Valeo Schalter u Sensoren GmbH, Volkswagen, Ford, Jaguar Land Rover. Its purpose has been the Detection of specific targets in some critical driving conditions with the focus on Active braking for Pedestrian Protection Support (APPS).

A.2.2 Safety contribution and socio-economic benefitSafety Benefit expected with the 24GHz-NB standard mode

24GHz-NB is an enabling technology for enhanced active safety systems and in particular the mitigation of front-end crashes thus reducing damages and saving of lives.

Accidents involving vehicles is related to traffic situations in which a faster reaction of the driver could have avoided crashes. Consequently, there is an increased need and appreciation for obstacle detection systems that operate at day and night.

The new generation of low-cost 24GHz-NB radars planed for 2013 will allow a quick deployment of the safety features on all cars.

Specific Safety Benefit added with the WLAM Mode

WLAM will use the same 20dBm max e.i.r.p as for the standard ISM mode: this relatively high power allows pedestrian detection with a maximum range < 15m

This range is intermediate between the range of ultrasonic sensors (<6m) and the range of front cameras (25m for pedestrians with low-cost technologies)

The strategy for WLAM Mode activation, is based on

o A permanent activation when reversing out of a parking place to better discriminate pedestrians approaching behind the car in parking areas

o An activation limited by a minimum speed for front driving, WLAM being activated by the front camera when reporting an “imminent crash alert with a pedestrian in path”

o Collision Mitigation by braking to reduce the speed of a potential impact and complement the passive protection devices tested up to 40km/h (EuroNCAP). See below:

ETSI


Furthermore, the analysis of accidents with pedestrian (France 2008) show most of the fatalities happen:

o In urban areas (70%)o When the pedestrian is crossing the road (70%)o On the pedestrian cross-path or closer than 50m from the cross-path (70%)

ETSI


A.2.3 Global 24GHz-NB regulationsThe 24GHz-ISM band has been implemented for the “Movement Detection & Alert” category in all the main countries, since supported by a ITU recommendation for SRDs (Short Range Devices)

The standards applying are usually based on either the FCC standard or the EU standard

Step by step a 200MHz x 20dBm max e.i.r.p has been allocated in all the countries, JAPAN is the last country where the 200MHz approval is not yet completed (the approval process has been started)

Countries Standard

Identical/Similar to

--------------------------------------------------------------------------------------------------------------------------

USA/CANADA FCC

MEXICO FCC

BRAZIL FCC

CHINA/TAIWAN FCC

--------------------------------------------------------------------------------------------------------------------------

EUROPEAN COMMUNITY EU new harmonized standard recently approved

Rest of EUROPE EU

RUSSIA EU

KOREA EU

--------------------------------------------------------------------------------------------------------------------------

JAPAN SPECIFIC

The currently available regulations in other administrations for WLAM are the following:

USA: Parts 15.245 (see note 3) and 15.249 (see note 4), in general Part 15.

Japan RADIOLOCATION – Unlicensed Low, Power Services in Annex 6-3-2-11

Canada: RSS-210 ]

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Annex B:Technical information

B.1 Technical description

B.1.1 24GHz-NB systems overview

The 24GHz NB radars are typically using FMCW or LFMSK signals (sweeping frequency principles).

Their main characteristics can be summarized in the two charts below, and shows

24GHz NB can cover short and mid range applications, but not long range applications

24GHz NB is using multi-beam or high speed resolution techniques to perform a monitor the road traffic to the front and to the rear

A WLAM mode will improve the range resolution in certain critical driving situations, and be sufficient to improve the performance in some specific driving situations where a larger bandwidth is critical.

B.1.2 Design considerations to go from 24GHz-NB to WLAM systems

The implementation of WLAM will be a limited evolution of the 24GHz-NB products since the power, signals and signal processing will remain the same as for the ISM standard mode.

The following table gives the braking distance to reduce the impact speed by 50%, and takes into account the following assumptions

Braking force (g) 0,7

Delay to get requested brake demand (s) 0,3

Time to get active WLAM tracking (s) 0,3

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SPEED (in kph)

30 40 50 60 70

speed in m/s 8,3 11,1 13,9 16,7 19,4

Breaking Time in sec (to 0 kph) 1,8 2,2 2,6 3,0 3,4

Distance (in m) 10,1 15,7 22,4 30,2 39,2

Breaking Time in sec (half speed) 1,2 1,4 1,6 1,8 2,0

Distance (in m) 8,8 13,4 18,9 25,2 32,3

Time to Colision camera in sec (25m range) 3,0 2,3 1,8 1,5 1,3

WLAM Activation Delay in sec 0,3 0,3 0,3 0,3 0,3

WLAM max activation duration 2,7 2,0 1,5 1,2 1,0

WLAM min activation duration to half speed 1,2 1,4 1,6 1,8 2,0

WLAM min activation duration to zero 1,8 2,2 2,6

WLAM avge activation time x 100% det. rate 1,6 s

WLAM avge activation x 80% det. rate at 25m 1,3 s

Final speed after braking (in kph) 0 0 25 38 53

Active Safety Sequence with WLAM activation

Step1: The front camera will be first to detect a pedestrian in path and will report an alert to trigger WLAM activation

Step2: WLAM will be activated, the radar will confirm the detection Step3: The braking system is activated to reduce the speed of impact or stop the car before the impact

In urban areas, the WLAM activation duration will be typically in the range of 1-1,5s when taking into account the probability of detection of the camera.

To be consistent with the ultrasonic range coverage, a min activation speed of 30kph is targeted for WLAM.

ETSI


B.1.3 Overall WLAM activation conditions

The overall activation conditions of WLAM can be summarized in the table below

Scenarios Rear Front

Driving Driving

Low-speed X NO

Activation Permanent

with rear gear

High-speed NO X

Activation Above 30kph

+ crash assessment

The potential crash assessment criteria are the following:

Crash

Assessment

Criteria

Pedestrian in Path Activation triggered by a front camera

Car trajectory loss of control

Activation triggered by the braking system (ESP)

Emergency Braking Activation triggered by the braking system, when

reporting an imminent crash alert, i.e. when a driver initiated panic braking is detected

Pedestrian in Path will be the main activity factor for WLAM

ETSI


B.2 Technical justifications for spectrum

B.2.1 Power issues

Inband: Max e.i.r.p for WLAM will be the same as for the standard ISM Mode: +20 dBm max e.i.r.p

WLAM needs a 20dBm power to achieve a good detection capability of pedestrians and keep a consistent tracking performance before and after the activation of the WLAM Mode

The ISM mode will be the standard mode of the WLAM system, with an activity factor of 99,5%

The unwanted emissions in the out-of-band domain in the frequency band 23.6 GHz to 24 GHz are proposed to not exceed – 73 dBm/MHz e.i.r.p. to achieve co-existence with the passive services.

a) Direct emission limit in the main beam will not exceed -73 dBm/MHz e.i.r.p.b) Additional average antenna attenuation above 30° elevation to be separately measured will be at least 20 dB.

The out of band emissions in the frequency range above 24,50 GHz are below – 60 dBm/MHz e.i.r.p which is the co-existence level defined in the ECC report 23 for a 100% SRR penetration rate.

Other emissions below 23.6 GHz and above 25,4 GHz that are not in any association to the wanted emissions (e.g. from digital circuitry, microprocessors) are pursuant to the limits in ERC Recommendation 74-01 [i.7].

WLAM systems are carrier-based systems. They are mostly using frequency sweeping modulations like FMCW or LFMSK. A pure FMCW spectrum has very much reduced out of band emissions as shown below.

ETSI


The existing 24GHz ISM automotive radars are compliant with the ERC/70-03 recommendation related to SRD devices, in the category “movement detection and alert”.

The out of band emissions are specified in term of peak values.

In Europe, the ETSI standard EN 300 440 applies for the devices operating in the 24,05-24,25GHz band. The specification gives -30dBm as a maximum peak value.

As a first step, a first investigation was realized with a certified lab (Cetecom) with an existing 24Ghz ISM automotive radar already in production and using FMCW modulations.

The tests have shown the following out of band emissions:

a -54 to -56dBm peak value

a -66dBm/MHz rms value (10dB lower) except for very few local peaks

a -66dBm/MHz rms value was also measured when the sensor was OFF, only the very few peaks disappeared, which means the -66dBm/MHz was the noise floor.

It shows at least the co-existence e.i.r.p level (-60dBm/MHz) defined in ECC-Report 23 for a 100% penetration rate can be satisfied in the ISM standard mode of WLAM. See table below (excerpt from ECC Report 23).

24Ghz ISM systems already in production and WLAM systems will have the same spectrum characteristics when using the same modulations

Below is an example of Out of Band emissions of a 24GHz ISM automotive sensor in production realized by a certified lab (Cetecom).

ETSI


ETSI


B.2.2 Frequency issuesWLAM is using an extended bandwidth of 450MHz (200MHz in the standard ISM mode) : 24,05-24,50GHz

This bandwidth is compliant with the generic deployment of the fixed services above 24,50 GHz

Figure 2: Frequency Allocation WLAM / Fixed Services

Figure B.2.3 WLAM bandwidth choice

ETSI

24,05 GHz 24,25 GHz

WLAM

Mode

ISM

Band

+20dBm

112 MHz49 MHz 47 MHz

8 x 112 MHz channels 8 x 112 MHz channels




256 x 3.5 MHz channels 256 x 3.5 MHz channels

24.500 GHz 25.445 GHz 25.557 GHz 26.500 GHz


49 MHz

49 MHz

49 MHz

49 MHz

49 MHz

47 MHz

47 MHz

47 MHz

47 MHz

47 MHz

112 MHz

112 MHz

112 MHz

112 MHz

112 MHz

Guard Band Guard Band Guard Band

(a) 112 MHz channels (3.5 MHz x 32)

(b) 56 MHz channels (3.5 MHz x 16)

(c) 28 MHz channels (3.5 MHz x 8)

(d) 14 MHz channels (3.5 MHz x 4)

(e) 7 MHz channels (3.5 MHz x 2)

(f) 3.5 MHz channels


B.2.3 WLAM activity Factor

The WLAM activity factor is limited to avoid the risk of interference and estimated to <1% in average

This document gives some new inputs to achieve a controllable activity factor for WLAM systems operating in the 24.05-24,50 GHz band.

The activation conditions proposed for WLAM are related to 2 specific driving modes: the rear parking mode and the active safety driving mode.

Rear Parking Mode (pedestrian detection improvement in parking lots): parking is a repetitive driving sequence, and the rear parking mode corresponds to the rear-gear position. The definition of the activity factor fully applies.

Active Safety Driving Mode (detection improvement at emergency braking or at roll-out): this driving sequence is not repetitive but:

o Is clearly defined by a decision of the car system to automatically activate reversible actuators such as brakes and belt pre-tensioning to mitigate the impact of a crash: in a similar way, WLAM can be considered as a reversible detection mode activated to mitigate the impact of an imminent crash.

o Corresponds to a low contribution of the overall activity factor (< 10%) as shown by US-NHTSA studies about the occurrence of Forward Collision Warning events

Controllability of WLAM activation: in any case the activation of WLAM cannot be triggered by the radar sensor itself, but must be activated by the car system.

Activity Factor Estimate: o The overall activity factor of 0,5% is mainly due to the rear parking modeo A significant shielding effect is expected in addition for the rear parking mode

ETSI


B.2.3.1- Activation conditions of the WLAM mode

The activation of the WLAM mode is by definition limited to a very small percentage of the time of the overall radar operation to minimize the interference risks.

There are two types of activation for the WLAM mode:

Rear Parking mode: This mode is a repetitive and specific sequence of driving,

Active safety mode: This mode is an emergency mode triggered by a safety risk assessment coming from several information available at vehicle system level. A critical situation has been detected, an imminent crash alert event has been reported to the driver which leads to an automatic activation of reversible active safety systems (automatic braking, belt pre-tensioning…).

The first type of activation is compliant with the definition mentioned in the TLPR report: it is measurable, repeatable and related to a specific driving sequence.

The second type of activation is not repetitive since corresponding to an emergency mode. Nevertheless

the driving sequence is clearly defined: the active safety mode is triggered by the car system based on several information which leads to an imminent crash assessment. The active safety mode means the AUTOMATIC activation of reversible actuators related to an imminent crash situation such as emergency braking, belt pre-tensioning,… In a similar way, WLAM can be considered as a reversible detection mode specific to an imminent crash situation.

the contribution of this sequence to the overall activity is very low

B.2.3.2 Controllability of the WLAM mode

The activation of WLAM cannot be triggered by the automotive sensor alone

The activation of WLAM must be triggered either by

the position of the gear box indicated by the car system (rear parking mode)

an authorization coming from a sensing data fusion ECU or from another vehicle system ECU which is doing the threat assessment.

.

B.2.3.3 Scenario 1: Active Safety ModeNHTSA (USA) assessed the occurrence related to a FCW automatic braking system with 10 vehicles and 66 different drivers.

ETSI


The system was active above 32km/h (activation above 45km/h, deactivation below 32km/h)

The occurrence of the crash-imminent alerts were found was 6,2 alerts for 1000km travelled.

The Active safety Mode Occurrence is about 1 event every 161km.

The WLAM activation duration will be in the range of 2,6s which is the reference time to set-up a FCW alert to the driver.

B.2.3.4 Scenario 2: Urban and Rural Parking modeScenarios coming from the urban and rural scenarios included in the SRR compatibility study

A B C D E

Parking parallel ortho. in-door average Activity Car parking nber of

Operations parking parking parking activation Factor Density events WLAM

in/out of slot in s 12s / 0s 8s / 0s in-door time in % of see per km2 systems

avge time outdoor 6s 4s 0s (s) travel time report23 per s activated

Urban 40% 40% 20% 4,0 0,4% 453 1,9 7,6

(*) veh/km2

B=2xA/32x60 D= B x C E= A x D

Rural 50% 50% 0 5,0 0,5% 123 0,6 3,2

2 events veh/km2

every 32 min D= B x C E= A x D

(*) Average Travel duration of 32min - see INSEE statistics over 18 millions people in France

ETSI


B.2.3.5- Scenario 3: High Density Parking ModeThis scenario is based on a regional mall parking with about 2000 outdoor parking places (i.e. Ludwigsburg Breunninger Mall) which can be considered as a worst case scenario.

For a football stadium, a first investigation has shown the parking size is bigger but the proportion of in-door slots is also very high since there is not enough space to implement big outdoor parkings (München Allianz Arena, Stuttgart Daimler Stadium, Stade de Paris, Palais de Bercy…).

A B C D E

Parking parallel ortho. in-door average Parkingpeak vol/h parking nber of

Operations parking parking parking activation Size in % of events WLAM

in/out of slot in s 12s / 0s 8s / 0s time ( slots ) capacity per second systems

avge time outdoor 6s 4s 0s (s) activated

High Density 0% 100% 0% 4,0 2000 100% 0,6 2,2

special

event D=BxC/3600 E= A x D

The hourly peak volume / hour ratio of 100% is a parameter used to design parking lots for special event locations - cf Parking Structures Book cf annex A

This scenario is not very different from the Urban and Rural scenario in terms of cars radiating simultaneously.

Shielding effect for a parking manoeuvre between 2 cars is based on 10 dB attenuation for a 20° angle above the road surface, and is derived from the ECC report 23 shielding curve.

Max Range (Rmax) between sensor (s) and obstacle (o) to get a 10dB shielding effect

Rmax = (Ho – Hs) / tan (22,5°)

For a 1,5m height car, Rmax = 2,40 m

a hR

Receiver

ad

aR

SRR Sensor

Parallel parking manoeuvre in a street, between 2 cars:

ETSI


Orthogonal parking manoeuvre in a parking lot, between 2 cars:

The shielding effect when parking between 2 cars is about 50%

Shielding effect due to infrastructure:

For a 10m height building, Rmax = 23 m

This shows the interference risk related to WLAM systems operating in a city will apply only locally to the street where the victim is installed

A first investigation of the street density in Stuttgart, Paris Ludwigsburg, Argenteuil shows figures between 13 and 40 streets / km2

Assuming all street are parallel in a one km2 area (worst case implementation), it means only 1 out of 13 WLAM systems can interfere with the victim installed in the street

In a city, the shielding effect due to infrastructure will likely be above 90%

Car shielding

When vehicles, queuing on roads become closer, the proceeding car/van acts as shielding towards the FS victim antenna.Tests have been carried out and additional attenuation has been evaluated, as a function of the clearance or obstruction angle shown in Figures 11 and 12.

a

hR

Receiver

SRR Sensor

ad

aR

Figure 11: Sketch of a LOS-connection between SRR and receiver.

a hR

Receiver

ad

aR

SRR Sensor

Figure 12: Sketch of an NLOS-connection between SRR and receiver.

The measured attenuation and the assumed linear model for the attenuation are shown in Figure 13, which shows relative shielding loss LS as function of the difference between the elevation angle a to the top of shielding vehicle and the LOS-angle aR. The shielding loss is normalised with regard to received power in the absence of any shielding object between transmitter. The red curve gives a simplified shielding model to be used in the calculations:

LS = 0 for a-aR < -2

ETSI


LS = 2.2*( a-aR) +4.4 for –2 < ( a-aR) < 8

LS = 22 for (a-aR) > 8.

-5

0

5

10

15

20

25

30

-10 -5 0 5 10 15 20

a-aR [°]

Measured Shielding Loss

Shielding Model for Calculations

Figure 13: Results of shielding measurement

B.2.3.6- Overall activity factor for the WLAM mode

The activity factor for the WLAM mode at 20dBm eirp is estimated to about 0,5%

This doesn’t take into account any shielding effect. When considering the shielding effect due to infrastructure or car parked nearby, the activity factor which is related to an effective interference risk will decrease significantly.

Collision Mitigation Activation duration Occurrence Travel duration Activity Factor

for each event for each event between events

Roll-out 2,6s from imminent crash alert very low >> automatic braking

(Active safety mode) with belt-pretensioning required

Rear-End Collision 2,6s from Imminent crash alert 6,2 events / 1000km 38,4 x 32 min 0,004%

(Active safety mode) with automatic braking required

Pedestrian in path parallel parking in (12s) & out (0s) 2 events / travel 2 events every 32min 0,52%

(Rear Parking Mode) orthogonal parking in (8s) & out (0s) 5,0s in average avge travel duration

for in/out operations

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Active safety mode 0,004%

Rear parking mode 0,52%

TOTAL 0,52%

Some periodic calibration tones will also be required at a much lower power between the WLAM sequences in order to switch the WLAM mode very fast. To be defined later.

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B.2.3.7 Statistics about Travel Duration

Report published in March 2007 by INSEE: French statistics related to 18 Millions of French workers, allocated to the different home & work situations in France

The average travel duration is 32 min in rush hours (high density of cars)

The average travel is 26km

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B.2.3.8 Crash Alert OccurenceCrash Alert Occurrence for a FCW system active above 32km/h

Extract of the NHTSA report dated Mar2006 – Evaluation of an automotive rear-end collision avoidance system (ACAS) - Ref DOT-VNTSC-NHTSA-06-01 / DOT HS 810 569

EXECUTIVE SUMMARY

This report presents the results of an independent evaluation by the Volpe Center to assess an automotive rear-end crash avoidance system built by General Motors and Delphi Electronics for light-vehicle applications.

According to the 2002 National Automotive Sampling System/ General Estimates System (NASS/GES) crash database, light vehicles were involved in approximately1.8 million police-reported rear-end crashes in the United States or about 29 percent of all light-vehicle crashes. These rear-end crashes resulted in about 850,000 injured people.

System Description

This rear-end crash avoidance system is known as the Automotive Collision Avoidance System (ACAS), which consists of both forward crash warning (FCW) and adaptive cruise control (ACC) functions. The FCW detects, assesses, and alerts the driver of a potential hazard in the forward region of the host vehicle.

The FCW is automatically functional when the host vehicle speed exceeds 25 mph (40 km/h), and becomes inactive when the speed falls below 20 mph (32km/h).

The ACC uses automatic brake and throttle to maintain speed and longitudinal headway control. The maximum braking authority of ACC is 0.3g. Cautionary alerts are visually presented by means of a color head-up display (HUD).

Crash imminent alerts consist of both a flashing visual display (HUD) and an auditory alert from a speaker embedded in the dashboard, which occur simultaneously. The driver can set the gap headway of ACC between 1 and 2 seconds.

The ACC possesses a warning capability that takes into account the braking ACC can provide. In integrating FCW and ACC functions, the ACAS is intended to improve automotive safety by assisting drivers to avoid rear-end crashes.

Description of Field Operational Test

The ACAS underwent a field operational test (FOT) that was conducted with 10 equipped vehicles from March 2003 to November 2004. 96 subjects were selected from the State of Michigan as FOT participants, 66 of which were exposed to the final version of the ACAS that was evaluated in this report.

Each subject drove the ACAS-equipped vehicle as his or her own personal car for a test period of four weeks, unsupervised and unrestricted. The first week was dedicated to collecting baseline driving data, i.e., without the assistance of the ACAS. During this week, FOT subjects drove with manual control and also had the option of using conventional cruise control (CCC). During the remaining three weeks, driving was performed with the assistance of the ACAS. In that period, subjects drove the FOT vehicles with either manual control or manual control augmented with the FCW function, and they also had the option of engaging ACC. It should be noted that FOT subjects could not disable the FCW function during ACAS-enabled test period. Two hours of training were provided for FOT participants prior to starting the FOT.

Independent Evaluation Goals

Goals of the independent evaluation of ACAS were to: characterize ACAS performance and capability; achieve a detailed understanding of ACAS safety benefits; and determine driver acceptance of ACAS. The independent evaluation sought to address these 3 goals to support the decision process in the deployment of crash avoidance systems..

6.1.2 System Capability & Alert Occurrence

The analysis of 8-second video episodes triggered by the auditory crash-imminent alerts revealed the following:

· Subjects received 6.2 crash-imminent alerts per 1,000 km travelled overall during the FOT.

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However, this alert rate was 21.8 crash-imminent alerts per 1,000 km travelled between 25 and 35 mph.

· In-path targets triggered 3.5 crash-imminent alerts per 1,000 km travelled. The majority of these alerts, or 3.4 alerts per 1,000 Km, were attributed to moving targets.

-About 0.4 crash-imminent alert per 1,000 km travelled was issued for moving in-path targets due to host vehicle changing lanes, turning, or passing behind an in-path moving vehicle.

-In contrast, about 1.5 moving in-path target alerts per 1,000 km travelled were caused by a lead vehicle changing lanes, turning, or making left turn across the path of the host vehicle.

· Out-of-path targets caused 2.7 crash-imminent alerts per 1,000 km travelled. The majority of these alerts, or 2.3 alerts per 1,000 km traveled, were due to stationary targets.

· In response to crash alerts, Subjects did nothing or simply eased up on the throttle in close to 40% of the episodes.

Subjects braked in about 55% of the episodes. About 55% of the subjects had an average reaction time of 0.5s or less after an in-path target alert. This suggests that subjects were attentive to respond to the situation ahead when they received the crash alerts.

· 38% of the drivers appeared to be distracted, within 5s before the alert, based on an analysis of recorded facial images.

Driver eyes were away from the road ahead for at least 1.5s before the crash alert in 3% of all alert episodes.

B.2.3.9 Parking structures Design RulesParking structures Von Anthony P. Chrest, Mary S. Smith, Sam Bhuyan

3rd Edition - 2001 - 856 pages

Parking Structures provides a single-source reference for parking structure designers, builders, and owners. This third edition is still the only such book. It addresses how to select the best functional and structural designs for a given situation, ensure long-term durability, design for easy maintenance, decide on the number and placement of entrances and exits, design an easily understood way finding system, design for ADA compliance, plan for internal auto and pedestrian traffic circulation, select the most effective and energy efficient lighting system, avoid the most common design and construction pitfalls, provide for adequate patron safety and security, carry out needed repairs, and extend the parking structure life.

Parking Structures addresses all the major issues related to parking garages. It is an essential reference for parking structure owners, structural engineers, architects, contractors, and other professionals. New in the third edition :

This third edition of Parking Structures includes new material on metric dimensions and recommendations for functional design globally, new research on flow capacity (Typical Peak hour volumes) and queuing at parking entry/exits:.

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Dimensions of parking lots (Conference in Berlin 2007)

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B.2.3.10 Rear Parking Manoeuvre Durations

The rear parking duration taken into account depends on the type of parking manoeuvres:

Parallel Parking : 12s reversing time out of 15s for a complete manoeuvre (see below)

12s to drive backwards + turn into the slot + reversing into the slot

3s to complete the manoeuvre by moving forward again

Orthogonal Parking : 8s reversing manoeuvre (simpler manoeuvre)

Front Parking : 0s reversing manoeuvre (no reversing operation)

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B.3 Information on performance benchmarking with other short range radar solutions

Figure B.1.1 provides an overview over the key parameters as Doppler (object distance) resolution, the angle resolution and range or object discrimination resolution.

The comparison shows that SRRs operating at the highest frequency and with high bandwidth provides the best SRR performance.

Figure B.1.1: Automotive Radar performance overview and evolution of systems

The 24 GHz narrowband radar uses the higher emission levels of the ISM band, the resolution of objects to be detected is limited by the available frequency bandwidth which is 200 MHz maximum. In order to provide the same functionality as UWB SRRs the system would have to employ several different sensor modules or restrict the functionality e.g. to distance measurements only.

The UWB SRR systems operating in the 24,15 GHz ± 2,5 GHz or 24 to 29 GHz range provide a higher spatial resolution given by the higher bandwidth. Also the range of the forward distance measurement to objects or cars is from near zero to about 30 meters. Several modules installed e.g. in front and backward bumpers provide a surround looking performance (see figure A.1).

The 77 GHz ACC radar is designed for long range forward looking distance measurement with narrow beam forming and combined with limited scanning performance. The systems are designed for automotive cruise control primarily on highways to maintain distance to proceeding vehicles within a pre-settable speed limit. The operating range is up to approximately 150 m but the minimum operational distance is 30 m.

The 79 GHz systems provide enhances performance for all three functions as measuring distance resolution, the detection and position determination of smaller object sizes and the relative velocity to other cars. The smaller size provides more designer freedom which is a continued requirement from the car industry.

The fact that the radar frequencies for ACC 77 GHz and 79 GHz SRR are adjacently allocated bands allows the combination of both sensor technologies in a single module. This lowers the system cost as compared to individual sensor modules provided for ACC and SRR individually.

The combined installation 24 GHz SRRs with 76 GHz ACC provides the optimum of safety functionality and is already practiced in cars on the road [Error: Reference source not found].

Annex C:Expected compatibility issues

C.1 Existing allocationsTable C1, allocations in the range of 24.25 to 24,50 GHzhttp://www.ero.dk/doc98/official/pdf/Rep025.pdf

FREQUENCY BAND ALLOCATIONS APPLICATIONS

24.05 - 24.25 GHz RADIOLOCATION Amateur Earth Exploration-Satellite (active) Fixed Mobile

Amateur (24.0 - 24.25 GHz) ISM (24.0 - 24.25 GHz) Non-specific SRDs (24.0 - 24.25 GHz) SAP/SAB and ENG/OB (24.0 - 24.5 GHz) Defence systems Detection of movement

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∆

∆R

∆24 GHzNarrow-BandBW 200MHz max

∆R

24/26 GHzUWB 5 GHz BW

∆R

∆77 GHz

1 GHz BW

∆V

∆79 GHz4 GHz BW

Legend:

Doppler resolution of object distance is RF frequency dependant Higher RF frequency enables better Doppler resolutionFor a given aperture, the resolution increases with frequency. Angular resolution depends on antenna aperture.

∆V: Velocity Axis

: Angle Axis

: Range Axis

The smaller the cubic, the better the radar performance

Sensor Performance

∆V ∆V ∆V∆R

∆

∆R Range resolution or object discrimination by range depends on available

modulation bandwidth

http://www.ero.dk/doc98/official/pdf/Rep025.pdf

Weather satellites Detection of movement (24.05 - 27.0 GHz)

24.25 - 24.45 GHz FIXED MOBILE

SAP/SAB and ENG/OB (24.0 - 24.5 GHz) Detection of movement (24.05 - 27.0 GHz) SAP/SAB P to P audio links (24.25 - 24.5 GHz) SAP/SAB P to P video links (24.25 - 24.5 GHz)

24.45 - 24.5 GHz FIXED MOBILE

SAP/SAB and ENG/OB (24.0 - 24.5 GHz) Detection of movement (24.05 - 27.0 GHz) SAP/SAB P to P audio links (24.25 - 24.5 GHz) SAP/SAB P to P video links (24.25 - 24.5 GHz)

NB: in green the standard mode, in yellow the WLAM bandwidth extension

C.2 Coexistence and sharing issuesThis clause presents the result of compatibility studies between WLAM and temporary fixed P-P link at 24 GHz, for 2 scenarios:

- ECC Report 23 worst case scenario, with the WLAM in calibration mode- a scenario close to the previous one, between a temporary fixed SAP/SAB receiving antenna and the WLAM in

pedestrian detection mode

It is important to note that the WLAM mode will be activated only in some specific cases. The conditions of operations and the resulting estimated activity factor for all the possible modes.

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The main points are summarized here:

Mode or Activation

event

EIRP Modulation bandwidth

DC or maximum duration

Technical conditions of activation

probability of

activation

Calibration -8dBm 100 MHz

200 MHz

1%/s

2%/s

100 %

Pedestrian detection

20dBm 450 MHz 1.8s at 30 km/h

2.6s at 40 km/h

- V>30km/h, and

- Emergency breaking signal from crash assessment system

0.6 %

Table 1: WLAM activation

C.2.1 Scenario with WLAM in calibration mode

A fixed link is parallel to a road on a 3km length.

The scenario proposes to calculate the aggregated interference from several cars considering 1 active frontward radar per car.

Figure 1: Scenario (extract from ECC Report 23 Figure 17)

The characteristics of the fixed point-to-point link and the scenario configuration are those described in ECC Report 23:

- Noise floor : -168 dBm/Hz

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- FS reception bandwidth : 1 MHz

- FS antenna height : 10m

- FS antenna offset to road : 10m

- Car spacing : 20m

- Rain attenuation : 0.6dB/km

- Car shielding : see formula in ECC Report 23, § 4.1.1.4.6 (p27)

- Bumper attenuation : 3 dB

WLAM emitter

The WLAM signal considered is a CW calibration tone chosen randomly in the frequency band 24 400 MHz to 24 500 MHz with a -8 dBm e.i.r.p.:

- EIRPWLAM = -8 dBm

- BWLAM = 100 MHz with DC=1%/s, or

- BWLAM = 200 MHz minimum, with DC=2%/s,

It must be noted that both signals lead to a total mitigation of 40 dB (DC+PF, see following sub sections).

Vertical and horizontal antenna attenuations are detailed in XXX.

PF mitigation factor applicable to WLAM calibration mode

Since the WLAM calibration tone is a random CW signal chosen over a frequency bandwidth larger than the victim reception bandwidth, a mitigation factor accounting for the probability the interfering signal is within the victim bandwidth can be taken into account. This is similar to the “probability factor” described in ECC report 134:

WLAM emissions takes N different frequency values distributed over a frequency modulation range B WLAM much larger than the FS reception bandwidth (BFS), a probability factor accounting for the probability of the WLAM frequency to fall into the FS reception bandwidth BFS can be expressed as:

PF = 10 log (NFS / N)

With:

- NFS the number of points falling into the frequency range BFS

- N the total number of points over the frequency range BWLAM

For a discrete WLAM signal with N different values homogeneously distributed over BWLAM, we have:

- NFS = BFS* N/BWLAM

- NWLAM = N

For a continuous VR signal such as FMCW with a frequency sweep speed S over BWLAM, we have:

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- NFS = BFS* S

- NWLAM = Bvr * S

Thus for WLAM signals with a discrete (homogeneously distributed) or continuous sweeping frequency in BFS, the probability factor is:

PF = 10 log (BFS / BWLAM)

Application to BFS=1MHz and BWLAM=100 MHz gives PF=-20 dB.

Application to BFS=1MHz and BWLAM=200 MHz gives PF=-23 dB.

1.1.1. DC mitigation factor applicable to WLAM calibration mode

DC = 1%/s corresponds to -20 dB

DC = 2%/s corresponds to -17 dB

Results

Figure below shows the interference level coming from one individual WLAM to the FS receiver according to the WLAM location on the road: The maximum interference level comes from the WLAM located at 1140m.

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Figure 2: I level per WLAM according to the distance

The aggregated interference level coming from all vehicles on the 3km road are shown in Figure 3: For the worst case scenario considered here, I/N=-23.6dB, which is 3.6 dB below protection criterion of I/N=-20 dB.

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Figure 3: Aggregated interference level from WLAM, ECC Report 23 worst case scenario.

C.2.2 Temporary fixed receiver versus WLAM for pedestrian detectionScenario description

The purpose here is to evaluate the impact of a WLAM on a receiver of a temporary fixed link (SAP/SAB). The scenario –inspired from previous section- is a SAP/SAB temporary fixed receiver located on the roof of a building located 10m from a straight road parallel to the temporary fixed link. The interfering signals come from a WLAM activated for pedestrian detection at a traffic light, since pedestrian detection is likely to occur on traffic lights locations where pedestrian can cross the road.

The characteristics of the victim are those provided in contributions to the 2 previous SE24 meetings.

The scenario is therefore as follows:

- Maximum I level : -131.2 dBW (in 30MHz)

- FS reception bandwidth : 30 MHz

- FS antenna height : 10m

- FS antenna offset to road : 10m

- Rain attenuation : 0.6dB/km

- Shielding effect : None

- Bumper attenuation : 3 dB

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WLAM emitter

The WLAM signal considered is a FMCW in the frequency band 24 050MHz to 24 500 MHz with 20 dBm e.i.r.p.:

- BWLAM = 450 MHz

- EIRPWLAM = 20 dBm

Mitigation factors applicable WLAM in this scenario:

- PF=10*log(30/450)=-11.7 dB

Results

Results are shown Figure 4, for a 10m FS antenna height (3-floor building) in blue and a 30m antenna height (10-floor building) in black.

For a 10m FS antenna height, the interference level coming from a WLAM vehicle varies from less than -60dB to 6.4 dB, depending on the WLAM location. The worst case occurs when the WLAM is located at 1140m from the SAB/SAB receiver, with an interference signal 6.4 dB above maximum interference level.

For a 30m antenna height, the protection criterion is respected, even at the worst location (2180m from the receiver).

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Figure 4: I towards the SAP/SAB receiver according to the distance, FS antenna height 10m (blue) and 30m (black)

The probability of a pedestrian detection event at a traffic light is lower than 0.012 %. Indeed, statistics show that the probability a vehicle exceeds 30km/h is 40%, the traffic light is red in average every 2mn, the maximum WLAM duration at 30 km/h is 1.8s, and the probability of having crash imminent alert is 2%1. Put together, these values lead to a probability of having an emergency breaking due to a pedestrian detection at a traffic light of 40%*1.8/120*2%= 0.012%.

Besides, the probability of having a road parallel to a temporary fixed link and thus having WLAM pointing at the SAP/SAB temporary fixed receiver in its main beam is not considered here. The statistics of such a configuration are very low according to SRR studies.

For instance the FS beam width at -3dB is about 0.8°, thus the probability that the WLAM is located within the temporary fixed link is about 1.6°/360°=0.44%.

Finally, in a urban environment, a 10m antenna height is likely to have line of sight issues over a distance above 500/1000m.

Conclusions

1 Value estimated from the NHTSA report, which indicates a maximum occurrence 21.8 crash imminent alerts for 1000 km, which is equivalent to 0.02 events per km.

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For ECC Report 23 worst case scenario, with the WLAM in calibration mode, the aggregated interference level is 3.6 dB below the protection criterion I/N=-20dB.

For the scenario between SAP/SAB temporary fixed receiver and the WLAM in pedestrian detection mode, the interference level exceeds Imax up to 6.4 dB. However one must bear in mind that this result is related to a worst case scenario with a SAP/SAB temporary fixed link parallel to a road, and a probability of interference by a WLAM activated for pedestrian detection of 0.012%.

New coexistence studies are needed, most notably for co-existence with SAP-SAB devices.

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History

Document history

V1.1.1. 001 December 29th 2009 1st draft for review from rapporteur for submission to ERM TG SRR approval via correspondence.

V1.1.1_002 1st February 2010 2nd draft from rapporteur

V1.1.1_003 4. February 2010 3rd draft: Incorporation of comments from Josef Schuermann

V1.1.1_004 9th February 2010 4th draft: review of the rapporteur

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