120
E. Fraccaroli and D. Quaglia
is identified by a Universally Unique Identifier (UUID), with official services
(Bluetooth profiles) assigned a short form UUID (16 bits rather than the full
128).
• Low Energy Attribute Protocol (ATT). It is similar in scope to SDP but
specially adapted and simplified for Bluetooth Low Energy. It allows a client
to read and/or write certain attributes exposed by the server in a non-complex,
low-power friendly manner.
• Low Energy Security Manager Protocol (SMP). It is used by Bluetooth Low
Energy for pairing and transport specific key distribution.
• Serial Port Profile (SPP). It emulates a serial communication interface (like RS232 or a UART). It sends bursts of data between two devices as if there were RX
and TX lines connected between them.
• Generic Access Profile (GAP). It dictates how Bluetooth LE devices interact
with each other. GAP can be considered to define the BLE topmost control
layer, given that it specifies how devices perform control procedures such
as device discovery, connection, security establishment, and others to ensure
interoperability and to allow data exchange to take place between devices from
different vendors [24].
• Generic Attribute Profile (GATT). It establishes in detail how to exchange all
profile and user data over a BLE connection. In contrast with GAP, which defines
the low-level interactions with devices, GATT deals only with actual data transfer
procedures and formats [24]. The GATT Profile specifies the structure in which
profile data is exchanged as depicted in Fig. 3.12. This structure defines basic
elements such as services and characteristics, used in a profile. The top level of
the hierarchy is a profile. A profile is composed of one or more services necessary
to fulfill a use-case. A service is composed of characteristics or references to
other services. Each characteristic contains a value and may contain optional
information about the value. The service and characteristic and the components
of the characteristic (i.e., value and descriptors) contain the profile data and are
all stored in Attributes on the server [25].
• Mesh Profile. It is used by Bluetooth Low Energy devices to communicate with
other Bluetooth Low Energy devices in the network. Each device can pass the
information forward to other Bluetooth Low Energy devices creating a “mesh”
effect.
There are many other profiles in today’s Bluetooth. Some of them, related to
healthcare, sporting, and fitness, boosted the spreading of IoT applications based on
wearable devices, e.g., to monitor blood pressure or physical activity.
Proximity sensing applications have been enabled by the long battery life
of low-energy Bluetooth devices. Manufacturers of iBeacon devices implement
the appropriate specifications for their device to make use of proximity sensing
capabilities supported by Apple’s iOS devices [26]. Relevant application profiles
include:
• FMP, the “find me” profile. It allows one device to issue an alert on a second
misplaced device.
E. Fraccaroli and D. Quaglia
is identified by a Universally Unique Identifier (UUID), with official services
(Bluetooth profiles) assigned a short form UUID (16 bits rather than the full
128).
• Low Energy Attribute Protocol (ATT). It is similar in scope to SDP but
specially adapted and simplified for Bluetooth Low Energy. It allows a client
to read and/or write certain attributes exposed by the server in a non-complex,
low-power friendly manner.
• Low Energy Security Manager Protocol (SMP). It is used by Bluetooth Low
Energy for pairing and transport specific key distribution.
• Serial Port Profile (SPP). It emulates a serial communication interface (like RS232 or a UART). It sends bursts of data between two devices as if there were RX
and TX lines connected between them.
• Generic Access Profile (GAP). It dictates how Bluetooth LE devices interact
with each other. GAP can be considered to define the BLE topmost control
layer, given that it specifies how devices perform control procedures such
as device discovery, connection, security establishment, and others to ensure
interoperability and to allow data exchange to take place between devices from
different vendors [24].
• Generic Attribute Profile (GATT). It establishes in detail how to exchange all
profile and user data over a BLE connection. In contrast with GAP, which defines
the low-level interactions with devices, GATT deals only with actual data transfer
procedures and formats [24]. The GATT Profile specifies the structure in which
profile data is exchanged as depicted in Fig. 3.12. This structure defines basic
elements such as services and characteristics, used in a profile. The top level of
the hierarchy is a profile. A profile is composed of one or more services necessary
to fulfill a use-case. A service is composed of characteristics or references to
other services. Each characteristic contains a value and may contain optional
information about the value. The service and characteristic and the components
of the characteristic (i.e., value and descriptors) contain the profile data and are
all stored in Attributes on the server [25].
• Mesh Profile. It is used by Bluetooth Low Energy devices to communicate with
other Bluetooth Low Energy devices in the network. Each device can pass the
information forward to other Bluetooth Low Energy devices creating a “mesh”
effect.
There are many other profiles in today’s Bluetooth. Some of them, related to
healthcare, sporting, and fitness, boosted the spreading of IoT applications based on
wearable devices, e.g., to monitor blood pressure or physical activity.
Proximity sensing applications have been enabled by the long battery life
of low-energy Bluetooth devices. Manufacturers of iBeacon devices implement
the appropriate specifications for their device to make use of proximity sensing
capabilities supported by Apple’s iOS devices [26]. Relevant application profiles
include:
• FMP, the “find me” profile. It allows one device to issue an alert on a second
misplaced device.