RF Micro Devices - Bluetooth

Wireless Interference Challenge

Bluetooth® wireless technology
shares the same 2.4GHz ISM (Industrial, Scientific & Medical)
band as other technologies and products such as Wi-Fi® (IEEE
802.11b), cordless phones and microwave ovens. Serious interference
issues can occur when more than one of these products is in
use at the same time - negatively impacting the performance
of the devices (i.e. static, dropped connections, etc.).
Bluetooth® & 802.11
Issues

The interference issues are even more severe when antennas
for both Bluetooth and 802.11 wireless technologies
are located within a meter of each other (for example, in
a notebook PC). The diagram below illustrates the Bluetooth
and 802.11 wireless interference issues.


Delivering Coexistence Solutions

Working with the Bluetooth Special Interest Group
(SIG) and other industry-leaders, RFMD has developed coexistence
solutions that allow users to operate Bluetooth and
other 2.4GHz wireless technologies simultaneously while maintaining
optimal system throughput, range and responsiveness. In office
environments this enables Bluetooth applications such
as mouse, keyboard, printing, file transfer and portable device
synchronization to run at the same time the user is connected
a network using 802.11. At home this means that mobile phones
and headsets enabled with Bluetooth technology can
operate efficiently even when microwave ovens, cordless phones,
and Wi-Fi® access points are in use.



RFMD supports a wide range of coexistence solutions to help
overcome the inherent interference challenges in today's wireless
world:

• Adaptive Frequency
  Hopping


• UltimateBlue™
  Coexistence Technology


• Packet Traffic Arbitration


• Intel®
  Wireless Coexistence System

Adaptive Frequency
Hopping

RFMD played a leading role in
the Bluetooth SIG's efforts to respond to the growing
issue of interference in the 2.4GHz wireless space by helping
to develop Adaptive Frequency Hopping (AFH).



AFH works within the 2.4 GHz spectrum to take advantage of
the available frequencies without limiting the Bluetooth
transmission to a set of frequencies occupied by other technologies
(such as cordless telephones, microwave ovens and certain
Wireless Local Area Networking technologies, including IEEE
802.11b and IEEE 802.11g). This "adaptive hopping"
allows for more efficient transmission within the spectrum,
thereby providing the user with greater performance, even
if using other technologies along with Bluetooth wireless
technology.



Adaptive Frequency Hopping (AFH) is one of the key new features
of the recently released Bluetooth Version 1.2 Specification.




All of RFMD's UltimateBlue™
single-chip solutions are Bluetooth Specification
Version 1.2 compliant and support AFH.


UltimateBlue™
Coexistence Technology

RFMD has developed UltimateBlue
Coexistence Technology, a coexistence solution specifically
designed to address the unique interference issues when Bluetooth
and 802.11 wireless technologies are collocated in the same
device (such as a notebook PC).





› Minimizes the interference between Bluetooth
  wireless technology and 802.11, while   maximizing
the data throughput of both   technologies when
they are used   simultaneously.

› Enhances the Adaptive Frequency
Hopping   (AFH) feature of Bluetooth V1.2
and also   improves the performance of previous
  generations of Bluetooth V1.1 devices.



› UltimateBlue Coexistence Technology
is a free   feature that can be enabled on any of
RFMD's   UltimateBlue
single-chip solutions.



Key features of UltimateBlue Coexistence Technology include:

› Works
with virtually all 802.11b/g chipsets

› No hardware
design restrictions

››
802.11 solution can be any form factor
(mini PCI, PC Card, etc.)

››
No interface signals between 802.11 and
Bluetooth ICs required

› No impact
to certification

››
Complaint with WECA, BQB, FCC and WHQL

› No impact
to system software or drivers

››
Compliant to existing software and device
drivers

› Forward
and backward compatible

››
Provides interface protection for Bluetooth
V1.1 devices

Packet Traffic Arbitration

Packet Traffic Arbitration (PTA) is part of the 802.15.2
recommended practices. PTA is a collaborative Time Division
Duplex (TDD) mechanism that minimizes the Bluetooth/802.11
coexistence challenges when both wireless technologies are
collocated in the same device, are located in very close proximity
to one another, and may share an antenna. PTA is designed
with quality of service in mind and is essential for ensuring
that Bluetooth audio runs seamlessly with data transfers
over 802.11 This makes PTA an ideal coexistence solution for
use in mobile phones and PDAs.

PTA is a recommended practice for Wireless
LAN applications, and although it is not part of the Bluetooth
specification, RFMD will be supporting it in future chips.
RFMD's Packet Traffic Arbitration solution is designed to
be flexible enough to use with any Wireless LAN chipset.



Packet Traffic Arbitration Block Diagram


Intel® Wireless
Coexistence System

RFMD has collaborated with Intel to develop a Bluetooth
+ 802.11 wireless coexistence solution for Intel's
Centrino™ mobile technology. The Intel Wireless Coexistence
System (WCS) is based on RFMD's UltimateBlue
single-chip solutions and enables simultaneous operation
of both Bluetooth and 802.11 wireless technologies.

Contact your local Intel FAE/TME for more
information on the Intel Wireless Coexistence System.

Already have an Intel Wireless Coexistence
platform? Contact
RFMD for Bluetooth firmware updates.

Mobile
Computing Information for Developers - Intel Website

Intel
Wireless Coexistence System - Intel Website