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Short Range Microwave Links: Present and Future

Objective


The main objectives of this project were the survey of, and recommendations on, all currently envisaged microwave applications in road transport informatics (RTI). This will facilitate the decision making process of how and where microwave techniques may be deployed in the integrated road transport environment (IRTE). Where applicable these aims will be reinforced by means of SMILER contributions to the areas of standardisation and frequency allocation.
Initially the project has surveyed the state of the art including technical aspects, research and development efforts in the field and identified functional requirements. The further objectives of this project were then to make a comparative evaluation of 3 existing microwave technologies in the 2.5 and 9.9 GHz bands for short range communications between roadside equipment and vehicles, to compare these technologies with alternative link technologies such as cable systems, infrared links, to attempt to define more clearly the application fields and requirements for medium range (100 to 300 m) devices for use in applications such as anticollision systems or for vehicle to vehicle communications, to study the feasibility of a low cost radar front end using a planar quasioptical design, and to evaluate it by means of a laboratory prototype, to evaluate the suitability of the millimetric band (60 GHz region) for vehicle to vehicle communication links, in a typical road environment and to study the theory and feasibility of a unified link able to fulfil the requirements of road to vehicle and vehicle to vehicle communication, working in the 60 Ghz region.

The objective of the research was to study the feasibility of a low cost radar front end for anticollision (AC) purposes. The main function of the AC radar is to assist drivers (ie to reduce reaction time in dangerous situations) under such conditions as bad visibility (fog, rain) or reduced vigilance (night driving). When driving on motorways or main roads with low or moderate traffic. The research took into account the following considerations:
the functional and technical requirements of AC radars;
alternative detection systems (eg, laser, acoustic);
automatic breaking systems;
systems exchanging vehicle data;
antenna parameters;
different methods of modulation.
Practical road trials have been carried out on an experimental system and the feasibility has been demonstrated.

The objective of the research was to investigate performance of a physical communication link between a road vehicle and a roadside beacon in the 1 to 10 GHz frequency range. The research concentrated on characteristics such as attenuation in air or due to a conducting layer on the windscreen near the transmitting antenna. The effect of multipath propagation was also studied and the range and the directivity of the antennas was also regarded as important parameters.

Experimental measurements were carried out on an trial system in a typical urban setting. Measurements showed the importance of reflection and diffraction phenomena for a medium range link. At 10 GHz, it would be quite impossible to have a well defined covered area beyond which no communication was possible. Fluctuations in electric field amplitude were important, however, and from knowledge of the statistical characteristics of fading patterns one can derive the characteristics of the information which can be transferred (eg length, rate, etc).

The research was into an extension of a radar traffic data acquisition sensor which enables it to establish a unidirectional short range broadband communication link between the sensor and a vehicles passing below it. A possible application of the radar communication system is the field of dynamic traffic management.

The center frequency of the link is within the 61 GHz band. This choice of frequency may be available throughout Europe. The message is organized in telegrams each consisting of a fixed synchronization preamble of 64 bits and an occasionally updated data part. The total amount of data transmitted may exceed 50,000 bits at a vehicle speed of 200 kilometres per hour. No channel coding was found to be necessary to provide error free data reception. Nevertheless forward error correction may be advantageous because of attenuation due to windscreens and heavy weather conditions. Subband modulation based on amplitude shift keying (ASK) seems to be the best modulation method.

Structures suitable for monolithic integration of the 61 GHz components was proposed as monolithic integration technology makes possible cost effective mass production of radio frequency (RF) front ends or complete transceiver structures. The radar communication system could be extended full duplex bidirectional communications at the same time as the radar functions.
Two domains for the application of microwave links to RTI systems have been identified:
- short range (10 to 30 m) road vehicle links in the 1-10 GHz frequency band (such systems will shortly be in mass production),
- medium range (100 to 300 m) vehicle to vehicle links or anticollision radar, in the 24-36 GHz band. These systems are not so well defined and are just at the prototype stage.
Initially the project will survey the state of the art including technical aspects, R & D efforts in the field and identified functional requirements. The further objectives of this project are then to:
- make a comparative evaluation of the three existing microwave technologies in the 2.5 GHz, 6.6 GHz and 9.9 GHz bands for short range communications between roadside equipment and vehicles,
- compare these technologies with alternative link technologies such as cable systems, infrared light and microwaves in the millimetre bands around 60 GHz. The comparison will be on the basis of performance, cost, reliability and ease of installation,
- attempt to define more clearly the application fields and requirements for longer range (100 to 300 m) devices for use in applications such as anti-collision systems or for vehicle to vehicle communications,
- study the feasibility of a low cost radar front end using a planar quasi-optical design, and to evaluate it by means of a laboratory prototype,
- evaluate in a typical road environment an existing prototype vehicle to vehicle communication link,
- study the theory and feasibility of (by experiment) a unified link able to fulfil the requirements of road-to-vehicle and vehicle-to-vehicle communications.
Main Deliverables:
A recommendation report for implementation of a European microwave link for RTI applications and a survey of all potential microwave applications in RTI.

Coordinator

COMPAGNIE GENERALE D'AUTOMATISME (CGA)

Participants (8)

AEG AG
Germany
Address
Steinhoeft 9
22880 Wedel
Fondazione G. Marconi
Italy
Institut National de Recherche sur les Transports et leur Sécurité (INRETS)
France
Marconi Italiana SpA
Italy
Address
Via Palmanova 185
20132 Milano
SWEDISH INSTITUTE OF MICROELECTRONICS
Sweden
Siemens AG
Germany
Address
Otto-hahn-ring 6
81739 München
UNIVERSITE DE LILLE
France
Address

Lille
UNIVERSITE DE LILLE
France
Address

Lille