Bluetooth 3.0 just got official in the Spring
, and already we're hearing about Bluetooth 4.0. So much for the latest and greatest staying the latest and greatest, huh? The Bluetooth Special Interest Group (SIG) today announced the adoption of Bluetooth low energy wireless technology, which is the hallmark feature of the Bluetooth Core Specification Version 4.0. Of course, we already knew that a low energy spec of the protocol was on the way, but instead of being integrated into 3.0, it seems as if it won't be utilized until 4.0.
BT low energy has been a long time coming, and it's badly needed for lots of devices to really take advantage of short-range wireless communications. Some smaller devices have been missing out on Bluetooth, particularly ones that don't posses huge batteries to begin with. The Bluetooth SIG suggests that industries like healthcare, sports/fitness, security and home entertainment will be enhanced, and given that this spec will enable BT to be powered in coin-cell battery powered wireless products, we can't disagree with that gesture.
Some of the product highlights and technical details are pasted below. Bluetooth is really setting itself up to be the go-to wireless standard for device-to-device communication. BT 3.0 adds high-speed options, and if 4.0 brings low energy, it's pretty much the whole package. Hopefully we'll see a new influx of wireless headphones, media players and the like in the near future.
This enhancement to the Bluetooth Core Specification allows two
types of implementation, dual-mode and single-mode. In a dual-mode
implementation, Bluetooth low energy functionality is integrated
into an existing classic Bluetooth controller. The resulting
architecture shares much of classic Bluetooth technology’s
existing radio and functionality resulting in a minimal cost increase
compared to classic Bluetooth technology. Additionally,
manufacturers can use current classic Bluetooth (Bluetooth V2.1
+ EDR or Bluetooth V3.0 + HS) chips with the new low energy
stack, enhancing the development of classic Bluetooth devices
with new capabilities.
Data Transfers – Bluetooth low energy supports very
short data packets (8 octet minimum up to 27 octets maximum) that are
transferred at 1 Mbps. All connections use advanced sniff-subrating to
achieve ultra low duty cycles.
Frequency Hopping – Bluetooth low energy uses the
adaptive frequency hopping common to all versions of Bluetooth technology
to minimize interference from other technologies in the 2.4 GHz
ISM Band. Efficient multi-path benefits increase the link budgets and
Host Control – Bluetooth low energy places a significant
amount of intelligence in the controller, which allows the host to
sleep for longer periods of time and be woken up by the controller
only when the host needs to perform some action. This allows for the
greatest current savings since the host is assumed to consume more
power than the controller.
Latency – Bluetooth low energy can support connection
setup and data transfer as low as 3ms, allowing an application to form
a connection and then transfer authenticated data in few milliseconds
for a short communication burst before quickly tearing down the
Range – Increased modulation index provides a possible range
for Bluetooth low energy of over 100 meters.
Robustness – Bluetooth low energy uses a strong 24 bit
CRC on all packets ensuring the maximum robustness against
Strong Security – Full AES-128 encryption using CCM to provide
strong encryption and authentication of data packets.
Topology – Bluetooth low energy uses a 32 bit access
address on every packet for each slave, allowing billions of devices
to be connected. The technology is optimized for
one-to-one connections while allowing one-to-many connections using a
star topology. With the use of quick connections and disconnections,
data can move in a mesh-like topology without the complexities of
maintaining a mesh network.