High speed Bluetooth comes a step closer: enhanced data rate approved

by Guy Kewney | posted on 16 November 2004

As usual, Cambridge Silicon Radio has got first out of the blocks with the latest version (2.0) of the Bluetooth specification - and has got approval for its Bluecore4 chips, including EDR (enhanced data rate).

Guy Kewney

"Today's qualification of CSR's Bluecore4-external hardware and firmware means that CSR is now the only company to be offering fully qualified solution for v2.0 + EDR including all of the optional EDR features, to give higher speed data transfer and lower power consumption," said the company's official announcement.

The Bluetooth SIG announced last week that Bluetooth v2.0 of the specification was finalised with EDR incorporated as part of the specification. Bluecore4-external EDR silicon is in production and available now, said CSR.

With EDR, Bluetooth speeds go up more than double, and could be three times as quick. The theoretical maximum useful data transfer is 2.1 Megabits per second (Mbps) compared to the current 721 Kilobits per second (kbps) for standard rate Bluetooth. This is the "payload" speed, not the basic signalling rate, which moves up from 1 megabit to about 3 megabits.

"This increase in transfer rate also means that, for a given amount of data, the EDR radio will be active up to 3 times less than a standard v2.0 radio, hence reducing power consumption, which greatly benefits battery-dependent mobile devices," observed CSR.

Anders Edlund, Marketing director, Bluetooth SIG, commented, "The Bluetooth SIG has finalised Bluetooth v2.0 specification with EDR and we look forward to the range of new exciting products and applications this higher-data rate, lower-power version of Bluetooth will deliver. It is therefore encouraging to know that companies are keen to get v2.0 and EDR technology into products as quickly as possible. CSR's Bluecore4 hardware and firmware is one of the first solutions to qualify to Bluetooth v2.0 and EDR, and provide the foundation for product developers to start work on bringing these benefits to consumers".

*Background from CSR about Bluecore4 and Bluetooth EDR

CSR Bluecore4 is fully backwards compatible with existing Bluetooth v1.1 and v1.2 devices. Bluetooth EDR achieves its higher data rates by using a Phase Shift Keying (PSK) modulation scheme in place of the Gaussian Frequency Shift Keying (GFSK) of basic rate. This allows more bits to be transmitted in each symbol of the packet's payload when it is sent over the radio link. However, the symbol rate is still 1 Megasymbol per second; the packet timing and structure are the same; the spectral characteristics of transmissions are virtually unchanged; and support for both modulation schemes is mandatory for all EDR capable products. Together, these characteristics provide excellent backward compatibility with Bluetooth v1.1 and v1.2. The new generation further improves on CSR's best-in-class reputation for the ease with which its Bluetooth solutions can be incorporated into circuits and end products.

CSR Bluecore4 is being made available in two variants - one for use with external Flash memory, and one with mask-ROM. Bluecore4-External, supplied in an 8x8mm BGA (ball grid array) package, is a highly flexible solution for markets that demand the ability to upgrade quickly. For example, combined with Bluecore's status of being the only silicon currently available to offer all mandatory and optional features of the Bluetooth v1.2 specification, Bluecore4-External presents the ideal solution for PC applications which can benefit from the ability to wirelessly transfer files up to 3-times faster or to operate multiple high-demand Bluetooth links simultaneously.

With the Bluetooth firmware committed to on-chip ROM, CSR Bluecore4-ROM offers lower costs and a much smaller footprint (3.8x4mm in a chip-scale package, or 6x6mm in a BGA which is pin-compatible with Bluecore2-ROM and Bluecore3-ROM). The ROM chip's size and cost makes it ideal for mobile phones, headsets and other mass-production, cost-sensitive applications which increasingly require Bluetooth functionality to be integrated.

Bluecore4 offers increased on-board RAM of 48 KB compared to 32 KB on previous Bluecore silicon. Some of this extra memory is required for additional buffer space to handle the Enhanced Data Rate, while the rest ensures that future specifications such as Scattermode will be fully supported.

Bluecore4-External and Bluecore4-ROM will initially bring the benefits of Bluetooth EDR's faster data rates to some of these existing key Bluetooth markets, speeding file transfers, reducing power consumption and enabling the operation of multiple simultaneous links. It will also open up some potential new application areas for the technology.

As mobile phones integrate higher resolution digital cameras, transferring the image files becomes time consuming - EDR Bluetooth means that a 1 MB image download, which currently takes about 12 seconds, will now only take 4 seconds.

PCs will increasingly be asked to support multiple Bluetooth links as users type on a Bluetooth keyboard and move a Bluetooth mouse while listening to music on a set of Bluetooth stereo headphones and synchronising contact details with their phone or using the phone as a modem to connect to an email or internet service.

As 'One Phone' converged cordless phone (using Bluetooth) and cellular phones (using 2.5 or 3G) with a single telephone number become popular, the higher speed Bluetooth radio connection from the cordless home or business access point will allow for the simultaneous transfer of more data whilst the telephone call is being placed over the fixed line infrastructure.

Bluetooth has previously been restricted to application in ink-jet printers but EDR will enable data to be transmitted at speeds suitable for laser printers.

The Bluetooth SIG is incorporating Bluetooth EDR as an addendum to the v2.0 specification.

Two megabits: does this take Bluetooth into small-screen video? - You can discuss this article on our discussion board.