Support for next-gen Bluetooth arrives

10 Mar 2006

With the 'need for speed,' the Bluetooth SIG developed version 2.0+EDR of the Bluetooth standard, with 'EDR' signifying Extended Data Rate. For Bluetooth devices, EDR means an increase in the maximum data rate from 1 MHz to 3 MHz. To make that happen, two new modulation schemes were implemented in the Bluetooth standard. Consequently, Bluetooth test equipment needs to be updated to meet the additional testing requirements.

'The motivation behind 2.0+EDR was to improve existing usage scenarios that require increased data throughput, like streaming CD-quality audio, digital image transfer and laser printing,' said Michael Foley, executive director of the Bluetooth SIG. Earlier versions of the Bluetooth Core Standard have a maximum data rate of 1 MHz. Version 2.0+EDR pushes that to 3 MHz by implementing two new modulation schemes in the payload section of the Bluetooth packet.

Earlier versions of the standard use a Gaussian-frequency-shift-keying (GFSK) modulation scheme across the packet. The result is a peak data rate of 1 Mbps. The trick in increasing the data rate in v2.0+EDR is to change the modulation scheme part way through when transmitting a packet. Specifically, v2.0+EDR changes from using GFSK at the beginning of the packet to a phase-shift-keying (PSK) technique when transmitting the payload section. The benefit is increased data rates while maintaining backward compatibility to earlier versions of the Bluetooth standard.

Of the two new modulation schemes, the p/4-DQPSK modulation scheme is mandatory in any v2.0+EDR compliant device. This is the scheme that provides a peak data rate of 2 MHz. The 8DPSK modulation scheme is optional. However, it is the scheme needed for a Bluetooth device to provide 3 MHz.

In either case, Bluetooth test equipment needs to be updated to test devices to the v2.0+EDR specifications. But currently there are not yet many test equipment options available.

For example, Frontline touts its FTS4BT Bluetooth protocol analyzer and packet sniffer as the 'World's only Bluetooth v2.0+EDR analyzer.' The FTS4BT can be used throughout the design-to-qualification cycle by product developers and test engineers. The analyzer works in real time to capture, decode and display data, while detecting protocol errors.

Protocol level testing

The Bluetooth SIG has selected Frontline to provide worldwide technical support for the SIG's Profile Tuning System (PTS) test tool. The PTS is part of Bluetooth's new qualification program and serves as a reference test system for Bluetooth profiles and protocols. Ideally, PTS will help make it easier for members in debugging, testing and certifying their Bluetooth devices while in general improving the interoperability of Bluetooth devices in the market.

For product developers and test engineers designing and testing Bluetooth v2.0+EDR hardware, there are now several new pieces of test gear available. Earlier this year Anritsu updated its MT8852 series of Bluetooth test equipment with the MT9952B - the first test instrument with both EDR and Adaptive Frequency Hopping testing capability. (Adaptive Frequency Hopping was one of the major and mandatory changes implemented in v1.2 because of interference problems occurring between Bluetooth and 802.11b/g WLAN. Both share some of the same frequency range, and Adaptive Frequency Hopping helps Bluetooth devices avoid those shared frequencies.)

The MT8852B includes a p4-DQPSK and 8DPSK signal generator and modulation analyzer for directly handling six of the eight EDR transmitter and receiver test cases. Each measurement can be run exactly in accordance with the v2.0+EDR specification for product validation during the product design cycle, or the MT8852B's test program can be edited to reduce test time in production environments. The model has a typical test time of less than 10 seconds for new EDR devices.

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