Microwave Engineering Europe - June 2008 - (Page 27)

BLUETOOTH 27 802.11 AMP and IMT-2000 services is that they operate in adjacent parts of the spectrum (see Table 1). The concern is that the use of 802.11 as a high-speed option for Bluetooth would have severe detrimental effects on other services operating in adjacent licensed frequency bands. In addition, even though the Bluetooth SIG intends to limit the 802.11 AMP to ﬁle transfer applications, once this high-speed radio functionality exists, users may decide to use it for video streaming (as described by Bluetooth press materials ). Because of their continuous nature, these streaming applications over an 802.11 AMP will have an even higher potential for interference than ﬁle transfers. Interference With multiple services in use simultaneously in a multimode device (as in the usage scenarios above), a Bluetooth 802.11 AMP may interfere with the operation of the other radios, leading to desensitization or even blocking of reception. If any of the blocked services are transmitting time-critical content, such as conversational audio or streaming media, the user experience can Table 1. Spectrum allocations. be poor. As an illustration, we will consider the use of WiMAX in conjunction with an 802.11 AMP. In the US, the 2.5 to 2.7 GHz range is licensed for use by WiMAX systems. Given its nearby proximity to the 2.4 GHz spectrum, WiMAX has little isolation from the out-of-band emissions originating from an 802.11 radio, which could dramatically hinder high-reliability WiMAX operation. Interference to WiMAX is being taken very seriously by designers for reasons which can be understood better from an interference study report published by the European Electronic Communications Committee (ECC) in February 2005. This report named The Protection Requirements of Radiocommunications Systems Below 10.6 GHz from Generic UWB Applications (also known as ‘Report 64’) includes IMT2000 services operating between 2.5 and 2.7 GHz as one of the ‘victim’ services of interest. Importantly, although this study focused on UWB being the interferer, the analysis was based purely on transmit power spectral xtnd your connctions wirlss.widband.mobil.powr.zigb.blutooth. Microwave Engineering ● June 2008 ● www.mwee.com http://www.mwee.com

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Microwave Engineering Europe - June 2008 Contents Comment News Cover Feature Designing and Simulating a Wireless LAN Antenna 60GHz: Achieving the Ultimate Wireless Dream New Radar Developments Include HFETs to Challenge DMOS/LDMOS and a 77-GHz CMOS PA for Automotive Applications Testing Raises Concerns Over 802.11-Based High-Speed Bluetooth IP2 & IP3 Design Considerations with Direct Conversion I/Q Demodulator Receiver Products Calendar

Microwave Engineering Europe - June 2008

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