Automotive Electronics
Car keys in the smart era
The humble car key no longer exists rather, as Huanyu Gu explains, it is being transformed into a key component in the all pervasive smart revolution
RF communication over such a distance requires much higher RF design effort. But the most significant impact is yet again the increase of power consumption. Drivers are accustomed to using their car keys continuously and may not want to frequently change or charge car key batteries. Increased system costs and power consumption will not stop the market introduction of two-way car key systems, but these factors have certainly driven OEMs, system suppliers and semiconductor companies to look for alternative solutions.
O
ver the past decade, ‘smart’ has become an increasingly common prefix used to describe a range of enhanced devices and objects: smart phones, smart meters, smart tags, the list goes on. The world has entered a smart era driven by two key mega-trends: connectivity and energy efficiency. These same mega-trends are shaping the automotive industry in the form of ‘connected mobility’ and ‘CO2 reduction’. While smart developments in CO2 reduction are being made in response to governmental calls to protect the environment, advances in connected mobility are being driven by consumer demand from a growing global driver population who are spending more time in their cars. As a result the humble car key has become an important part of this smart revolution, having undergone a significant transformation from 15 years ago when mechanical car keys were still the standard. Electronic immobilizers and remote keyless entry (RKE) systems are now standard car key features, while passive keyless entry and go (PKE/PKG) systems are becoming more popular. Such features are now available in many car models – and not only in Europe, North America and Japan, but also in emerging markets like China and India. However, the key can become smarter still as connected mobility enters its next phase. Drivers now want their cars to be
16 September 2011
internet-connected to request services from inside the car, to check the status of fuel or tire pressure anytime and anywhere, or even to turn on the heating system and monitor the car’s interior temperature from home. ‘Smart keys’ are now being created as part of a new system to bring this vision to life.
Two-way car key One obvious way of remotely checking and controlling car status is to extend the one way RF link from the key to the car to a bi- directional communication. This extension enables the key to send specific requests for car status and receive the responses from the car. However, such a two-way car key system faces a number of new challenges.
First of all, two-way keys need to be fitted with displays for showing car status data. A display not only significantly increases the system’s material costs, but also the power consumption of the key. Another challenge is to make fragile displays mechanically robust enough to operate in an automotive environment. While LED displays are an option, the amount and type of data that can be presented is limited, and it is less straightforward for drivers to read the information. Secondly, two-way keys would need to communicate with cars over longer distances than traditional one-way systems, typically up to 1 km. Reliable bi-directional
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Supporting NFC Ideas for alternative solutions have developed in the direction of enabling the car key to communicate with external devices, by introducing a new communication interface. In this way, information can be sent to and displayed on an external device that is already fitted with a screen, such as a smart phone. To enable new applications, standardised interfaces are desirable, such as USB or Bluetooth. But while popular in the PC world, they lack reliable mechanical contacts or draw too much power. Hence, it is better to use a contactless interface powered by the reader it communicates with (using the same principle as RFID), which doesn’t affect the car key battery at all.
One of the standardised contactless interfaces used in payment and transportation systems all over the world is ISO 14443 Type A. It operates at 13.56 MHz and has become part of ISO 18092 (Near Field Communication / NFC) in recent years. NFC is a technology which is being supported by several mobile phones already.
The idea of developing connected car keys that incorporate an ISO 14443 Type A interface in addition to existing immobilizer, RKE and PKE/PKG functions has been discussed among the various industry stakeholders and has received a positive response. Many new use cases are opened up by connecting the car key to existing ISO 14443 infrastructure.
New use cases The ISO 14443 Type A interface enables easy data exchange between a connected car key and any NFC-compliant devices, such as a mobile phone, an NFC-reader for PCs or even a contactless point of sale. The security of NFC communications should be enforced by the application through encryption and decryption of the data exchanged between the sender and receiver respectively.
Each time the car ignition is switched off,
car status data such as mileage, fuel level, GPS coordinates of current position and even car diagnostic information is written into the non-volatile memory of the key. To check this information later on, the driver simply needs to wave the car key over his/her NFC-compliant smart phone, and the car status data will be displayed. Similarly, the smart phone can read out the GPS coordinates of the car’s last parking position from the key, then download a map through the 3G connection which pinpoints the car’s location. If a GPS app is already installed, the phone will guide the driver back to his car. This car finder feature could be helpful for forgetful drivers or those who live in large cities such as New York or Beijing. With the car’s diagnostic data stored in
the key, the driver can also run a remote health check from home before beginning a long trip. To run the check, the driver places the car key close to an ISO 14443 Type A reader, either externally connected to his/her computer or internally integrated. The data is then transferred to the computer, uploaded and processed by the car manufacturer. A detailed report of the car’s health is generated and emailed to the driver.
Once it is confirmed that the car is in a good condition, the driver can plan their journey via online route planning services and then save the selected route into the key via the NFC-reader. When the driver gets into the car, the route data will be automatically uploaded to the car’s navigation system – no more stressful finger-tapping on the small car navigator screen necessary. With the ISO 14443 Type A interface in combination of a secure element, the connected key may even offer contactless credit card functionality and operate in conjunction with a contactless point of sale, provided the firmware and hardware of the key fulfill the high level of security required for applications such as cash payments.
Looking to the future Connected car keys supporting NFC overcome the high system cost and power consumption issues of two-way car keys. However, the connected key only stores the car’s data from the last time it was parked. Obtaining real-time car status data, such as its interior temperature, is not possible. On the other hand, the functions of a two-way car key are limited by the RF
communication distance. As such, neither the connected key nor the two-way key can currently replace each other. A third possibility could be using a mobile phone and GSM connection to perform car-related tasks. This could become practicable when telematics modules become widely available in cars. However, factors such as installation cost, GSM connection set-up delays for each operation and associated connection costs make the idea less attractive. This means that the hybrid system of two-way and connected keys remains the most promising solution for the automotive industry to enter the smart era by enabling drivers to communicate intelligently with their cars.
NXP Semiconductors |
www.nxp.com
Huanyu Gu is Product Marketing Manager, Car Access & Immobilization, at NXP Semiconductors
www.cieonline.co.uk
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