Bluetooth: A new challenge for wireless connection

These days, one very often comes across the question “Do you have Bluetooth in your mobile/devices?” You will find it very rare for someone to respond in the negative to this question. So if your answer is “No”, you may not be seen as technology savvy. But how well do they really know about Bluetooth technology?

Modern technology uses Bluetooth to connect devices wirelessly in the most efficient and easiest way. Today, Bluetooth allows users to swap data between mobile phones, personal device assistants (PDAs), notebook computers and a string of other devices within a few meters of each other.

The technology is not only limited to mobile devices or computers, but also extends to household appliances, medical devices, and so on. Hence, Bluetooth technology is used everyday and everywhere, not only for pleasure but also for saving lives.

There is an interesting history behind Bluetooth. Harald Blåtand was the King of Denmark from approximately AD940 to 985. During his reign, Blatand was reported to have united Denmark and Norway and to have brought Christianity to Scandinavia. Apparently “Blåtand” translates, at least loosely, to “Blue Tooth”. The origins of this name are uncertain, although it was relatively common in Blatand’s time for kings to have a distinguishing name.

A little more than 1,000 years later (May 1998), succumbing to an attack of Scandinavian pride, the giant Swedish telecom manufacturer Ericsson decided to honour old, weird Harald by naming its new wireless networking standard after him.

It convinced the founding Special Interest Group (SIG) co-partners Nokia, Toshiba, IBM and Intel that Bluetooth was the right name for the technology and, together, they set off to conquer the air.

In July of 2002, the Bluetooth SIG established its global headquarters in Overland Park, Kansas, USA. Membership of the group is open at two levels to all companies wishing to develop market and promote Bluetooth products – Associate and Adopter Members.

Bluetooth has now become popular worldwide among all modern technology users. Bluetooth-enabled products are now in the hands of one billion consumers worldwide, according to SIG.

At a rapid pace, products are on the market in significant numbers: volumes alone doubled from 2003 to 2004. According to ABI research (http://www.In-stat.com), Figure 1 shows the trends of selling Bluetooth products in terms of year.

The trade association announced that the installed base of Bluetooth devices reached one billion in early November 2006. The trend shows that growing consumer demands has pushed the number of Bluetooth units shipping per week to12 million.

Figure 1: Trends of selling Bluetooth products per year

Let us now consider the internal construction of this device. Normally, the device is a single chip based Integrated Circuit (IC) package. To fabricate IC package, CMOS technology is popular in semiconductor foundry (for example, XFab Sdn Bhd).

For Bluetooth applications, RF-CMOS (Radio Frequency) presents a very good compromise in terms of price and performance. It is also possible to integrate the flash memory (local storage device), which is not possible in BiCMOS (Bipolar Junction Transistor) as this would significantly increase the wafer price.

The device uses a globally available frequency band of 2.4GHz for worldwide compatibility.

Today, System-on-Chip (SoC) is one of the most attractive approaches to producing the smallest and portable devices. By this approach, several applications can be integrated into a single chip.

The advantages are compactness and quicker speed obtainable with low power. A great example of SoC is the latest model mobile phone (integrated Bluetooth, memory and LCD).

However, IC Design and Semiconductor Foundry Companies are also thinking of integrating Bluetooth with other applications. Figure 2 shows the basic internal block diagramme of a Bluetooth chip.

Using RF-CMOS, a true single-chip Bluetooth solution is developed and possible integration of additional external application features is included—such as power management, regulators, battery charger, and audio power amplifier.

 

Figure 2: Basic block of internal Bluetooth chip configuration

In February 2007, Broadcom (http://www.techsout.com), a renowned semiconductor manufacturer, introduced the Broadcom BCM4325 SoC connectivity chipset, which combines Bluetooth, an FM transceiver and Wi-Fi – all in a single silicon chip.

The Broadcom BCM4325 chipset features radio capabilities in a new ultra-low power CMOS SoC. This makes it possible to address the growing demand for a single product that powers devices with multiple applications such as Web-browsing, instant messaging (IM), e-mail, VoIP phone calls and photo sharing, by eliminating the need to use multiple chips.

Dr Syed Zahidul Islam is a lecturer with the School of Engineering, Swinburne University of Technology Sarawak Campus. He can be contacted at zsyed@swinburne.edu.my.