With the embedded model (which is already in use in millions of vehicles) the vehicle head unit is responsible for the HMI, all applications, and connectivity.
The embedded model has many advantages:
Connectivity — vehicle antennae are larger and more powerful than mobile phone antennae; and multiple antennae placed on vehicles exteriors provide better connectivity than cell phones, especially where cell network coverage is poor. Recognizing this, some in-vehicle systems, such as OnStar, even allow time on the vehicle phone to be billed to mobile phone accounts.
Safety and security — with no reliance on external devices (a smartphone), applications in the vehicle itself, and a more powerful antenna, embedded systems are less vulnerable to mishaps. For example, connectivity and functionality will not be lost because the driver has forgotten his smartphone.
HMI and branding — with full control of the user experience, automakers can use their infotainment systems both to differentiate their vehicles from the competition's offerings, and to reinforce their brand.
Figure 2: The embedded model connects directly to the cloud and benefits from the more powerful vehicle antennae.
Placing everything in the vehicle head unit has some disadvantages that weigh in against this model's many advantages. Chief among these are:
Cost — in exchange for control over the complete user experience, the automaker bears the costs of developing and adapting applications to offer a full range of features and capabilities.
Updates — to keep their systems current automakers must devise a strategy for reconciling the lifecycles of consumer devices and applications with their vehicles' lifecycles
Usability — while automakers can control the complete user experience offered by their infotainment systems, users may want to continue using their smartphones (with their applications) integrated with the in-vehicle system.
Billing — a separate phone in the vehicle means either that the user receives two separate phone bills, or that the vehicle manufacturer and mobile phone service provider must successfully negotiate joint billing agreements.
As with the embedded model, with tethering applications reside in and run exclusively on the vehicle head unit. The smartphone is relegated to tethering the in-vehicle system; that is, it provides connectivity to the cloud and not much else.
The advantages of tethering are chiefly in the realm of vehicle independence from the smartphone:
Independence — the system depends on the smartphone only for connectivity. Users can change or upgrade seamlessly to most phones.
Control — with applications residing and running only in the vehicle head unit, the automaker has complete control over them, and can filter what gets out to the driver and passengers and how it looks.
HMI and branding — with the HMI in the vehicle, the automaker defines how it looks and behaves, and how it is branded, and can thus use the infotainment system to reinforce brand recognition and loyalty.
Simplicity — there is no need to develop and re-develop interfaces for the plethora of phones on and coming on the market.
Tethering has some disadvantages that can seriously reduce its viability:
Cost — automakers must develop or adapt the applications they want available in their vehicles; this requires a considerable investment of time and money.
Updates — automakers are responsible for keeping their applications current, and must, therefore, devise a strategy for reconciling the lifecycles of consumer devices and applications with their vehicles' lifecycles.
Connectivity — connecting through the smartphone connectivity may in fact offer poorer service than connecting directly through the vehicle, which can have larger, more powerful antennae.
Figure 3: Tethering uses the smartphone as a data conduit and not much else.