Stephen Leotis
L02/Milor
Bluetooth Sound System
Current Widespread Bluetooth Technology: Bluetooth 2.1+EDR
Introduction
The wireless personal area network (WPAN) focuses on wirelessly connecting users to their
surrounding technology via short-range (~10m) ad-hoc connections. Bluetooth capable devices have the
capability to communicate with any other Bluetooth enabled device in close proximity. The currently
used widespread standard is Bluetooth 2.1+EDR. This new standard improves data transfer rate and
device pairing and optimizes power consumption. Bluetooth’s robustness, low cost, low power, and ease
of use have led to extensive product development in consumer, medical, and commercial realms [1]. This
paper scrutinizes current applications of Bluetooth 2.1+EDR and explains the use and implementation this
new technology.
Current Bluetooth Applications
The consumer market has been recently flooded with Bluetooth capable devices, mostly portable
ones. These devices require low power consumption and are easy to use. Apple markets products that
utilize Bluetooth technology including the iPhone 3GS and the iPod Touch. The iPhone 3GS and iPod
Touch use Bluetooth 2.1+EDR for WPAN connections via the inclusion of the Broadcom BCM4325 [2].
The Broadcom BCM4325 offers a single chip Wi-Fi, Bluetooth and FM receiver solution and satisfies the
needs of a highly mobile device that requires low power usage and dependable operation [3]. The iPhone,
like other Bluetooth capable cell phones, can utilize wireless Bluetooth hands-free headsets, stream music
via Bluetooth to a compatible receiver or headphone, and send files to Bluetooth enabled devices. The
iPhone 3GS currently retails for $199 and up (depending on built-in hard drive size) [4].
Because of its low power consumption, small size, and low cost, Bluetooth low energy
technology has recently been chosen as the wireless health device standard [5]. Before this official
adoption, wearable health monitoring devices were being developed for vital body parameters that
transmit the information to a computer, PDA, or central monitoring system. Alive Technologies has
developed a heart monitor, pulse oximeter, and a diabetes management system. When using the heart
monitor, a GPS and cell phone can be carried so that a user’s position, speed, ECG, and heart rate can be
monitored remotely in real-time using Bluetooth technology [6].
Bluetooth is currently being used in the development of ambient intelligence environment. These
environments use sensors that allow for people to interact with machines in their surroundings. Bluetooth
is the technology that enables these sensors to communicate with machines and a central computer.
Bluetooth 2.1+EDR allows for a greater number of sensors, more complex machine interaction, and better
response times from the system compared to previously released standards [7]. In addition to
environmental sensors, Bluetooth enabled sensors used for health monitoring can be integrated into these
intelligent environments [8].
Bluetooth 2.1+EDR Technology
Bluetooth technology operates by establishing ad-hoc networks with other local Bluetooth
enabled devices. One Bluetooth device is designated as the master while all other devices function as
slaves. The master device uses its clock to determine the entire synchronization of the frequency-hopping
spread spectrum (FHSS) channel hopping used by the piconet for communication. This pseudo-random
frequency hopping allows each device to have a specified time slot to transmit its data within the piconet
on one of the 79 different channels. The master device begins transmitting on even-numbered time slots
and may occupy up to five time slots. Slave devices may only communicate in response to receiving a
packet from the master device [9].
Bluetooth 2.1+EDR operates over a short-range using the 2.4 GHz unlicensed radio band. The
enhanced data rate is achievable through the use of phase shift keying (a method of representing bits
based on the phase shift of a reference signal). Using π/4 rotated differential encoded quaternary phase
shift keying (π/4-DQPSK), Bluetooth 2.1+EDR can achieve a 2 Mbps transmission rate. It can operate at
3 Mbps using differential encoded 8-ary phase shift keying (8DPSK). These higher speed transmission
rates allow for this new standard to handle much larger data transfers and maintain a more reliable
connection [10].
Implementation of Bluetooth Technology
Implementing Bluetooth technology into a new product can be done in three ways: using a
Bluetooth module, a pre-qualified Bluetooth chip set, or a Bluetooth-enabled Application Specific
Integrated Circuits (ASIC). The first implementation method requires a Bluetooth module. This method
is easiest and provides the shortest product development time, but these devices are expensive (around
$70 per unit) and inflexible. The second approach uses a pre-qualified Bluetooth chip set, a highlyintegrated single-chip solution for Bluetooth connectivity such as [2]. This option is the most common
among major system manufacturers, but using third party chip sets can compromise size, cost, and power
consumption of the system due to needed external components. The third method involves the use of an
ASIC. ASICs, although having higher product development costs, allow for the most control over the end
product characteristics including physical dimension, power consumption, and cost [11]. Once the
Bluetooth hardware is implemented into the product, it must be integrated into the system using software
(language varies with designer and interface) to fulfill the Bluetooth needs of the device.
[1]
Bluetooth Special Interest Group. (2007, Aug. 1). Bluetooth SIG Adopts New Core Version
2.1+EDR [Online]. Available:
http://www.bluetooth.com/Bluetooth/Press/SIG/BLUETOOTH_SIG_ADOPTS_NEW_CORE_V
ERSION_21__EDR.htm
[2]
G. A. Quirk. (2008, Oct. 13). iPod touch: Did Apple tip its hand?. EE Times [Online]. Available:
http://www.eetimes.com
[3]
Broadcom Corporation. (2007). BCM4325 Product Brief. [Online]. Available:
http://www.broadcom.com/collateral/pb/4325-PB00-R.pdf
[4]
Apple, Inc. (2009). iPhone [Online]. Available: http://www.apple.com/iphone/buy/
[5]
Bluetooth Special Interest Group. (2009, Jun. 8). Bluetooth Technology Chosen As Health Device
Standard [Online]. Available:
http://www.bluetooth.com/Bluetooth/Press/SIG/BLUETOOTH_TECHNOLOGY_CHOSEN_AS
_HEALTH_DEVICE_STANDARD.htm
[6]
Alive Technologies. (2009). Alive Technologies Products [Online]. Available:
http://www.alivetec.com/products.htm
[7]
L. Ling Xin, H. Zhang Qin, H. Yi Bin, L. Jing, and W. Shu Feng, "A Safe and Fast Connecting
Strategy of the Bluetooth Identification Sensors in Ambient Intelligence Environment," in Proc.
of the 2008 Int. Symp. on Information Processing [Online]. pp.538-542. Available:
http://ieeexplore.ieee.org
[8]
A. Tocino, J. Gutierrez, I. Navia, F. Penalvo, E. Castrejon, and J. Giner. (2009). Personal Health
Monitor. New Directions in Intelligent Interactive Multimedia Systems and Services – 2 [Online].
pp 465-475. Available: http://www.springerlink.com
[9]
J. F. Kurose and K. W. Rose, “Wireless and Mobile Networks,” in Computer Networking: A TopDown Approach, 4th ed. Boston, MA, Addison-Wesley, 2008, pp. 513-587.
[10]
Bluetooth Special Interest Group. (2007, Jul. 26). Core Specification v2.1 + EDR [Online].
Available: http://bluetooth.com/Bluetooth/Technology/Building/Specifications/Default.htm
[11]
Y. Goh and M. Eftimakis. (2009). Implementing a Bluetooth Solution – Chip Sets or ASICS?
[Online]. Available: http://www.design-reuse.com/articles/5369/implementing-a-bluetoothsolution-chip-sets-or-asics.html