1 Motivation for using Bluetooth PIM Profiles in Phone Connectivity Solutions

Bluetooth is the de-facto standard for wireless mobile device integration in the car. HFP, PBAP, AVRCP and A2DP are widely used and accepted by the customers for using the telephony functionality and music from their mobile devices.

The SAP (SIM-Access Profile) provides numerous benefits in comparison to the HFP (Hands Free Profile) when being applied to car-kit solutions. The Message Access Profile expands the integration of personal information by adding the messaging functionality for SMS, MMS and Email.

To keep up with changes of the market or just to improve existing features, existing Bluetooth specifications are updated regularly and new Bluetooth specifications are written.

The update to PBAP version 1.2 in 2013 added features that allow better performance, better knowledge about changes to contact information on the CE device and improvements in other aspects.

In 2014, the CTN profile was adopted which allows to integrate the calendar, task and notes functionality into the car. The release of this profile closes another gap in order to be able to offer the customer a safe, lawful and comfortable mobile office in the car.

Instant messaging became common and to keep up with that trend, the MAP specification was enhanced to version 1.3 in May 2016 to allow the transfer of instant messages and associated data like online/offline information of a conversation participant.

At the moment of creation of this document there are several HFP enhancements on the way.

The introduction of Bluetooth Low Energy opened a door to some completely new use cases and improvement of behaviors.CE4A is committed to use and implement Bluetooth in the car and to develop further or refine the existing specifications where necessary because Bluetooth is considered as the basic connectivity technology that needs to be present in cars for a very long time. The Bluetooth Qualification process leads to a certain level of quality as devices need to pass a number of tests in order to claim support for a certain Bluetooth Profile. This leads to interoperability and reliability which are important aspects in the automotive industry. Using Bluetooth does not contradict other developments like Android Auto, Apple CarPlay or MirrorLink. CE4A sees Bluetooth like “FM Radio” which is a mature option to integrate the data on the mobile phone into the car. Other technologies may provide better data rates or integration and will exist in parallel.

The main benefits are in the following areas:

  • Reeduced driver distraction
  • Seamless integration
  • Standardized solution
  • Interoperability and reliability
  • Optimized network coverage
  • Low complexity due to re-use of common industry standards
  • Enhanced telephony features when using SAP

1.1 Reduced driver distraction

The more functionality from a mobile device is transferred to the car the lower is the need for a customer to directly interact with the mobile device itself.

  • The carmakers have a long experience in how to prepare and present information in a secure and comfortable way to their customers.
  • This is not only done to enhance safety but also to fulfil legal requirements since it is prohibited to interact with a mobile device in some countries while driving.


1.2 Seamless integration

The mobile phone is a constant companion throughout our daily lives. At home it is wirelessly connected to loudspeakers to play music, to the TV or PC to view pictures and videos, to light bulbs and sometimes even to the weight scale or toothbrush.

In the car, most customers have their mobile devices connected via Bluetooth to use the telephony and music functionality. They are familiarized and satisfied by the solution. The new and updated profiles pave the way to add features using the same convenient solution.

1.3 Standardized solution

The profiles are standardized by the Bluetooth SIG and therefore allow an interoperable solution to provide the use cases for both, the carmakers and the mobile device manufacturers. The benefits from a standardized solution for any implementing company are:

  • Interoperable use of functionality
  • Reduction of the development costs
  • Reduction of the testing costs
  • Reduction of complexity of cross use cases

1.4 Optimized network coverage

SAP provides benefit in comparison to HFP in terms of network coverage:

  • When using SAP, the benefits regarding better reception quality and therefore optimized network coverage during driving, result in the fact that the car’s built-in phone module with direct connection to the car’s antenna is operated. There are no signal loss.
  • The benefit of SAP is increased when the car is equipped with metalized glass in order to reduce the car’s energy consumption for air conditioning with respect to environmental protection purposes. In such equipped cars there is loss of around 20 dB.
  • This signal loss results in quite huge areas with bad or no reception at all and much lower data transfer rates.
  • With HFP, an (indirect) access to the car’s antenna can only be achieved when using a consumer device cradle in which the consumer device is plugged and capacitive coupling is made. That is a customer’s disadvantage, as the customer is urged to buy a specific device cradle that is operable only with that specific consumer device. Due to a number of inconveniences to the customer, the market acceptance of cradles is very limited.
  • Due to this capacitive coupling of the phone’s antenna there is also a loss of 6 to 10 dB.

1.5 Low complexity due to re-use of common industry standards

To reduce the complexity of implementations Bluetooth Profiles re-use established formats like PBAP, MAP and CTN/GPP use OBEX, PAN uses IP, A2DP uses MP3 and AAC and SAP refers to standards from 3GPP. This reduces the number of interoperability issues when operating these profiles.

1.6 Enhanced telephony features when using SAP

The HFP profile is limited to a certain set of telephony-related commands. At present it does not enable the user to use all call-related features as described below. The SAP Profile is the only non-proprietary technology to execute the following use cases during driving.

Examples of these enhanced telephony use cases include:

  • Activate, deactivate and request the current status of Caller ID (CLIP, CLIR) 
  • Activate, deactivate and modify call forwarding
  • Modify manual or automatic network selection
  • Activate or deactivate “Data-Roaming” via the SIM
  • Display the Service Provider Name instead of Network Operator Name


CE4A considers the PIM Profiles to be an important Bluetooth profile that provides numerous advantages for the communication between car and consumer device to converge to a full mobile office in the car. Therefore CE4A’s requirements are:

  •  Use standardized solutions:

CE4A wishes to motivate to use standardized solutions. This allows interoperable use of functionality and therefore highly reduces the development and testing costs.

  •  Implement MAP with E-Mail and Instant Messaging support:

CE4A wishes to motivate to implement MAP email and Instant messaging support in all of their future products.

  • Implement SAP:

CE4A wishes to motivate to implement SAP in all of their future products.

  • Implement CTN:

CE4A wishes to motivate to implement MAP email and Instant messaging support in all of their future products.

  • Wi-Fi Use Cases:

CE4A to motivate to implement on four Use Cases to be implemented: Tethering with car using phone, phone using car (stationary and on the go), media streaming and automatic mode switch.

  • Wireless Charging:

CE4A wishes to motivate to implement the Wireless Charging use cases.

  • Digital Key, NFC and Bluetooth Low Energy:

CE4A wishes to motivate to implement the digital key, NFC and Bluetooth Low Energy use cases.