Antenna diversity boosts cellular performance - 3/17/2005 - EDN - CA509351

Antenna diversity boosts cellular performance - 3/17/2005 - EDN - CA509351: "As all mobile-handset users know, cellular networks are far from perfect. Every carrier has dead spots, and building cell sites is an expensive proposition. Start-up Magnolia Broadband, however, claims to have a magic potion for the carriers: a way to boost performance within the confines of the standards. Multiple potential technologies, such as MIMO (multiple in, multiple out), may over time greatly improve cellular-network performance, but most require a base-station upgrade. Magnolia believes that designers can integrate its antenna-diversity technology into handsets at low cost with no impact on the infrastructure.
Magnolia's president, Osmo Hautanen, states, �All carriers have similar problems. They need to maximize capacity by using the spectrum as efficiently as possible. And they need to offer faster data rates and improve in-building coverage.� Magnolia claims that its technology can double capacity and boost coverage area by 60%. Magnolia has just announced the DiversityPlus architecture, which the company based on the MBJ6502 baseband-support IC and the MBJ6501 RF vector-modulator IC. The 6501 integrates dual modulators to support CDMA phones in both the 800- and the 1900-MHz bands. The two chips sit between the handset-radio chip and the antenna and work their magic with only minor changes in the handset design.
The Magnolia technology works only on the upstream side of the cellular link. Starting approximately 18 months ago, designers began adding dual antennas for the downlink. Qualcomm�s 6500 chip uses antenna diversity on the downlink. But more data-centric applications require symmetric performance in both directions, and Magnolia claims to deliver that capability.
The company claims that South Korea�s SK Telecom (www.sktelecom.com) is developing the first "