Microwave Engineering Europe - June 2008 - (Page 30)

30 BLUETOOTH Figure 7 shows a WiMAX receiver’s desensitization caused by 802.11 AMP interference as a function of the distance between the 802.11 transmitter and WiMAX receiver. The desensitization computations assume -101 dBm as the sensitivity for WiMAX MAP messages (critical control messages transmitted in downlink signal), and the two curves correspond to desensitization of WiMAX systems in 2.3 and 2.5 GHz bands. Out-of-band emission levels of -51 and -60 dBm/MHz from an 802.11 radio are used, according to the measurement results described above, and free space path loss is considered. Observations and recommendations Analysis of real-world measurements shows that UWB AMP emission levels are sufﬁcient to protect IMT-2000 services at 2.3 / 2.6 GHz bands as per the protection requirements speciﬁed in ECC Report 64. Real-world measurements show that 802.11 AMP radios have the potential to interfere with IMT-2000 systems at 2.6 GHz even at 8 m separation (assuming free space loss and the -115 dBm/MHz max allowable interference PSD). For WiMAX, out-of-band emissions from an 802.11 AMP can desense a client station sitting 10 m away. Such effects can directly impact the capacity and functionality of these systems. As an industry, we need to take these user experience issues seriously. The success of high speed Bluetooth relies on the industry Figure 7: The desensitization of a WiMAX receiver increases as the distance between it and an 802.11 AMP decreases. understanding and addressing them before deploying them into the market. We also have the responsibility to protect licensed services from interfering with their proper operation. The appropriate next step would be to conduct adequate coexistence studies between 802.11-based high speed Bluetooth and licensed services in 2.3 / 2.5 GHz bands. Subsequently, the industry should consider developing mutual interference mitigation mechanisms for high-speed Bluetooth using the 802.11 AMP, based on the results of the coexistence study. Alternatively, the industry should exclusively move operation of the 802.11 AMP to 5 GHz. About the authors Dr. Roberto Aiello is co-founder and CTO at Staccato Communications. A recognized leader in the UWB community, he is actively involved in regulatory and standards-setting committees and is the author of more than 20 patents on UWB technology. Siddharth Shetty is a communication systems engineer at Staccato Communications. A graduate of University of Colorado, Boulder, he is an expert in spectrum regulations for Ultra-Wideband and a main contributor to the world-wide UWB standards and regulations. Intel a winner in Swedish 2.6 GHz auction Intel was one of the main winners in the second European 2.6 GHz spectrum auction, in Sweden, which raised SEK 2.1 billion (about $350 million) after a grueling 112 rounds of bidding over 16 days. The chip maker acquired 50 MHz (TDD) spectrum for SEK 159.2 million ($26.5 million) and will likely look for local partners to build and operate a mobile WiMAX network using the license. Intel says it will rent out the license to its chosen partners rather than sell it. Swedish network operator TeliaSonera paid the most for its license, $93 million for 2x20 MHz blocks, while H3G Access, a subsidiary of the operator of “3” branded mobile networks in several European countries, paid $49 million for just 20 MHz block of spectrum. Other winners in the 2.6 GHz auction, which the Swedish regulator stresses is technology and service neutral, included Tele2 and Telenor, both acquiring 2 x 20 MHz blocks. According to consultancy group Analysys Mason (Cambridge, England) the prices reﬂect “realistic” values for the spectrum that was auctioned, which it calculates came in at Euros 0.13/MHz/pop , with unpaired spectrum for going for just below Euro 0.04/MHz/pop. With auctions coming up in other European countries, including the U.K., Austria and the Netherlands, the outcome of the Swedish auction provides much needed information on the price that operators will pay for 2.6 GHz spectrum throughout Europe, the consultancy says. “Clearly prices fetched at the 2000/2001 European UMTS auctions, especially in the U.K. and Germany, are unlikely to be repeated. On the other hand, operators are reporting a rapid uptake of mobile broadband dongles, and new WiMAX players may be eager to enter the arena, suggesting that prices may still be substantial,” says Bart-Jan Sweers, Strategy Consultant at Analysys Mason. And the Analysys Mason take on the 2.6 GHz auction stresses acquiring frequencies is not the only way for operators to prepare for future demand. Refarming of 2G spectrum, the digital dividend and general easing of spectrum restrictions will improve the supply side of spectrum, while femtocells may well relieve any capacity issues. Despite being signiﬁcantly below the U.K. and German UMTS auctions in 2000, the prices achieved in the Swedish auction were considerably higher than the recent Norwegian 2.6 GHz auction, which came in at Euro 0.03/MHz/pop., the consultancy group notes. www.mwee.com/207603079 Microwave Engineering Europe ● June 2008 ● www.mwee.com http://www.mwee.com/207603079 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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