The challenge:

• You are driving at 130 km per hour on a motor way and you are notified about an accident few kilometres ahead, just before the last handy exit;
• You are approaching a traffic jam and your navigation system informs you of a better alternative route;
• You are facing an emergency situation and you would like to press a button and get immediate assistance;
• You would like to buy a present for your anniversary or get detailed information about fuel prices and the services offered by the next service station beside your way to home;

• You create a community with cars close to yours by chatting or playing interactive games;

…and it is all for free!

In a world where information travels everywhere in real-time, driving a car cannot represent a time in which we are disconnected. While driving there is a constant need for local information.

Inter-vehicle (V2V) and vehicle to infrastructure (V2I) communications will deliver this information and will extend the ‘range of awareness’.

• Cooperative driver assistance, emergency notification, overtaking assistance, obstacle warning;
• decentralized floating car data, traffic jam monitor, dynamic navigation, route weather forecast;
• user communications and information services, hot-spot Internet access, Mobile advertising, car community, fleet management.

When people thinks about V2V and V2I, they imagine and dream about a technology that creates a mobile and dynamic network, a sort of telematics connectivity tissue capable to manage a network where:

• wireless multi hop ad hoc networking, independent from the operating conditions, extends the ‘range of awareness’;
• very low data transmission delay allows for cooperative driver assistance and safety related applications;
• synchronised data, or within precise “time-slot”, allows the network to manage and deliver critical real time information between vehicles and vehicle to infrastructure;
• distributed knowledge of both network topology and position of the vehicle guaranties optimised data flow and geo-referenced services;
• unlicensed radiofrequency bands allows for distributed and low cost data transmission;
• everyone, car maker, service provider and user, can benefit from it.

These requirements on the radio communication system are mandatory: support of high bit rates; robustness in case of high relative velocities (from 10 Km/h to 300 Km/h); provisioning of multi hop connectivity even in low traffic density scenarios; and operation in unlicensed frequency bands.

Reicom role.
Without pretending to make here a full dissertation about the C2C-CC Radio System, we would like to pinpoint the advantage of a Reicom Radio, powered by HSBRA™ Inside, in combining the absolute must of Active Safety Application with both Traffic Efficiency and Infotainment Application.

The figure hereafter shows the C2C Communication Layers’ architecture of an OBU (On Board unit), as taken from “C2C_CC  Manifesto v1.1”, dated 28th August, 2007.

The C2C-CC distinguishes among three basic types of radio wireless technologies: IEEE 802.11 p wireless technology, conventional wireless LAN technologies based on IEEE 802.11 a/b/g, and other radio technologies (like GPRS, UMTS, HSDPA, WiMax, 4G).

As it can be seen in the protocol architecture, Non-Safety applications (Entertainment/infotainment and Internet access applications) shall only operate on Non-Safety dedicated channels or public channels. Non-Safety applications could also bypass the C2C Communication Network Layer and transceive data via the IEEE 802.11 a/b/g network interfaces, for example for direct communication with Wi-Fi hot spots.

Protocol architecture of the C2C Communication System

Recently the European Telecommunications Standards Institute (ETSI) has allocated for C2C-CC need the frequency band from 5.855 to 5.925 GHz, that the C2C-CC is planning to use in the following manner, see also figure hereafter:

• 10 MHz band from 5.885 to 5.895 GHz for network control and critical safety applications,
• 10 MHz band from 5.895 to 5.905 GHz for critical safety applications,
• three 10 MHz bands from 5.875 to 5.885 GHz and from 5.905 to 5.925 GHz for road safety and traffic efficiency applications, and
• two 10 MHz bands from 5.855 to 5.875 GHz for non-safety related car to roadside and car to car applications

ETSI Frequency bands for C2C application

Accordingly to this frequency schema, the C2C-CC envisaged the use of dual receivers. This concept is aimed to enable the C2C-CC Radio System to receive messages on two dedicated C2C-CC Channels simultaneously. The use of dual receivers should allow better utilization of the frequency band, even if would have considerably higher costs than a single receiver hardware solution.

The reason behind the adoption of such architecture is because people are not confident that 802.11p and OFDM modulation scheme can be reliable and robust enough to deliver, simultaneously, Safety critical application and Non-Safety critical application, i.e. Traffic Efficiency and Infotainment.
Because of this C2C-CC suggests to use conventional wireless LAN technologies based on IEEE 802.11 a/b/g, and other radio technologies (like GPRS, UMTS, HSDPA, WiMax, 4G) for Non Active Safety Application.
But the Car Industry is well aware of the technical and economical difficulties to succeed for this part of the Protocol architecture:

• IEEE 802.11 a/b/g, better known as Wi-Fi, do not provide real connectivity, regardless of the bandwidth, when vehicle moves and the network topology keeps changing very dynamically.
• GPRS, UMTS, HSDPA, WiMax and LTE in the future, besides the fact that they do not perform as originally expected and claimed by the industry, they do carry with them a business model of running cost that so far as hardly proved to be successful.

Hence how Reicom technologies can make a difference in the C2C-CC Protocol Communication stack?
Let’s redraw the previous ISO-OSI diagram accordingly to the enhancements derived from the adoption of both Reicom HSBRA™ digital Baseband and Clancast™ protocol stack.

New Protocol architecture of the C2C Communication System
using Reicom HSBRA™ and Clancast™

As it appears evident from the above figure, in this new scenario, the same IEEE 802.11 p, powered by HSBRA™ addresses both Safety e Non Safety Critical Application. The reason being that it guarantees stable, reliable and deterministic broadband link, up to 24 Mbps @ 350 Km/h, all from one single baseband.

Once we have the performances built into the radio, we then need the intelligence that supersedes it and, managing the network and the transport layers, delivers real services for the car industry and end users. Therefore beside the C2C Network and Transport layers that deliver Active Safety, we have Clancast™ that delivers, on the same PHY, Traffic Efficiency and infotainment.

This approach saves money and helps the deployment of new business model in which Active Safety, Traffic and Infotainment matters help and pull each other to success.

Not only, Clancast™ also manages Non-Safety applications (Entertainment/infotainment and Internet access applications) transceiveing data via the IEEE 802.11p, even when travelling at 200 or 300 km/h, as well as direct communications with Wi-Fi hot spots using the IEEE 802.11 a/b/g and Wi-Fi protocol stack. In fact, ClancastTM incorporates also the Wi-Fi protocol stack and switches the radio from the mobile IEEE 802.11p Clancast™ mode to the C2C mode as well as to the IEEE 802.11 a/b/g Wi-Fi access point or client within the same radio and the same Baseband.

Last but not least, to be compliant with existing solutions and to be operative when there isn’t any other kind of IEEE 802.11 network available, Clancast™ automatically manages the data switching between the IEEE 802.11 networks and the 3G and 4G world.