In addition to the above mechanisms, companies have also made enhancements through proprietary techniques. CSR for example, also manufactures an 802.11 b/g hardware solution for embedded applications (UniFi).
Due to its experience in embedded wireless technologies it has been able to develop further optimization measures via priority and channel signaling. CSR has implemented these additional features because even when current protection techniques are utilized there are still some co-existence issues.
Take the example of someone using a Bluetooth headset that is paired with a wireless VoIP phone for voice communication. The synchronous Bluetooth SCO connection can still be disrupted by the packet reception acknowledgements that Wi-Fi is forced to transmit—resulting in bad voice quality for the Bluetooth link.
With TDM and CSR's proprietary measures built into the UniFi device (with UMA-compliant 17 dBm radio frequency output power), synchronous Bluetooth HV3 packets do not cause interference.
In this and other instances, users who deploy both CSR's BlueCore and UniFi single-chip silicon are assured of seamless coexistence in foreseeable operating scenarios thanks to the additional measures that take account of the need for such technologies to work together.
Given the increasingly multimedia nature of state-of-the-art phones, such quality of service is likely to have a significant impact on the user experience in what is clearly unfolding as a huge global market. Using Bluetooth and Wi-Fi silicon from the same company can simplify and speed integration as well, reducing the number of suppliers to deal with for application support
Conclusion
Bluetooth and Wi-Fi technologies have made incredible progress in the years since they were first launched regarding the issues of both interference and power consumption.
Design engineers have made huge advancements in making Bluetooth and Wi-Fi silicon more power-efficient and robust with new approaches to chip architecture, low power modes and software implementations, researched to provide the best interference and power consumption solutions available.
Sophisticated methods and techniques have allowed the two technologies to be embedded, side by side, in the smallest of form factors.
Coexistence systems such as Adaptive Frequency Hopping (AFH), Time Division Multiplexing (TDM), power control and Channel Quality Driven Data Rates (CQDDR) have made the Bluetooth link more robust. However, wireless design does not stop at just employing techniques like AFH and TDM. Effective implementation lies with the ability to have highly integrated solutions with proprietary techniques that decrease the hurdle of designing the two technologies into one device.
The most appropriate choice for device designers is to integrate a combined Bluetooth + Wi-Fi solution that has been developed in conjunction with each other. Designers need ready-engineered coexistence solutions that are designed specifically to communicate between radios in order to intelligently reduce interference.
Solutions like CSR's have enhanced the user experience of Bluetooth as a complementary technology to other popular standards like 802.11b/g Wi-Fi but the real challenge that now lies ahead is combining Bluetooth and Wi-Fi on the same chip.
About the author
Simon Finch is vice president of CSR's Wi-Fi strategic business unit. Simon is responsible for the development of Wi-Fi technology, specifically for UniFi. Prior to joining CSR, Simon was Director of Engineering at Home Wireless Networks, and prior to this, Cambridge Consultants (CCL).
