No pain maximum gain: Carriers have myriad technologies to help ease the spectrum crunch

In mobile wireless, there's individual inescapable truth: spectrum is finite. brace that with a shift in Wall Street's expectations and ongoing development in minutes of use in voice and data, and the drive to maximize existing infrastructure is essential.

squeezing continues to mount as operators begin offering data services, a market the Strategis cluster projects will have a penetration rate of nearly 60 percent by dint of 2007. AT&T's launch of GSM/GPR data services and partnership with Cingular to build an overlay GSM network atop its TDMA network will likely be a big mover CDMA carriers like Verizon and Bell Canada have launched their 1XRTT data networks, and Sprint PC is not far behind.

flat moves like the FCC's representation cap lift from 45 MHz to 55 MHz are a quick fix; data services will eat up image quickly. While building more base stations is the easy answer, the realities of require to be paid [i]or[/i] undergone and zoning issues are forcing carriers to examine novel alternatives.

"There appear to bes to be this bright and glimmering mirage of of recent origin spectrum that always seems to advance away," said Metawave's Dr. Marty Feuerstein, senior vice president and general manager of proceeds development. "Carriers are being forced to be more efficient with their in every one's mouth spectrum as traditional ways of adding capacity diminish."

As a restorative smart antennas, high-gain amplifiers, optimization oftenness planning, and cryogenic filtering will enable carriers to not alone avoid deploying new base stations, on the other hand also improve the quality of existing networks.

Shaping the Beam

For many, smart antennas are seen as mobile wireless' final frontier, With modulation and coding reaching their limits, smart antennas can be used for load balancing, oftenness reuse and cochannel interference. They can be darted to existing base stations or draw near standard in new ones. There are sum of two units approaches: adaptive beamforming and its various implementations, and MIMO (multiple input, multiple output)

Solutions ne to integrate with existing towers and double capacity require to be paid [i]or[/i] undergone effectively. "The functional requirements and the take away from benefit have to be there," said Tom flexure director of research and unfolding for Sprint PCS. "Granted, representation is a valuable resource, on the contrary you can't pay any price for any solution."

To gain market traction, vendors have sought OEM partnerships in the United States and abroad. Metawave, for example, reached to Asia via Samsung to exhibit an embedded, adaptive array ASIC for 25G- and 3G-IXRTT and WCDMA. Metawave's Spotlight series can qualified the needs of CDMA, GSM and 3G networks. For CDMA, it proffers the Spotlight 2200 for traffic balancing and to restore handoff overhead; it's also an integrated solution for Lucent's Flexent base stations. Its Spotlight GSM proceeds integrates with existing base stations to improve capacity by dint of mitigating cochannel interference. In July Metawave will endow Verizon its three-sector antenna CDMA solution via its existing relationship with GTE AirTouch and Bell Atlantic,

ArrayComm has a nearness in Asia through Kyocera, with whom it helped facilitate China Telecom's deployment with luminous and ZTE. It also has relationships with Marconi to integrate its technology for WCDMA and with the combination of parts to form a whole on a Chip division of Telecom Italia Labs to examine smart antennas for 3G ArrayComm's Intellicell utilizes spatial channels where each traditional channel is used multiple times in each sector, lending itself to SDMA (spatial division multiple access). A full quantity to TDMA and CDMA. SDMA uses the spatial simple body to identify every user by the agency of its unique spatial signature.

by dint of utilizing adaptive beamforming from the base station with an antenna array that can faculty of perception how the environment looks at any given time in confines of interference sources, it tend hitherwards up with a processing strategy to optimize the user signal quality. In an adaptive antenna solution, a base station with an antenna array makes measurements upon the uplink environment, but the tricky part is the downlink: In greatest in quantity systems there's no feedback upon how well the antenna is working, in like manner it's a guessing game. This is a question at issue in a FDD (frequency division duplexing)based network because the uplink and downlink are separated through 50 MHz, and the environment can change rapidly above that frequency spread. To mitigate this dilemma, ArrayComm incorporates its smart antenna technology with adaptive beamforming technology and TDD (time division duplexing), which has an identical uplink. Along with its smart antenna technology, ArrayComm has been making strides abroad end partners with its iBurst data-only yield as an add-on serv ice to existing wireless networks. Similarly, Wireless Online is conducting trials of its GSM/GPR smart base station with Chinese OEM Shanghai Datang Mobile, In an earlier trial held in San Francisco, it delivered a 60-percent reduction in dropp calls with an average C/I improvement of 85 db and 3x improvement in coverage.

Large vendors are also developing solutions. Ericsson's GSM capacity booster an adaptive antenna solution consisting of an indoor base station and a passive array antenna with an integrated sector antenna, splits the sector into eight fixed subsectors. Within each subsector, the capacity booster dynamically prefers the best lobe to handle a call. Multibranch diversity is achieved by means of combining the best signals, improving quality by the agency of mitigating uplink and downlink interference. Nortel Networks has exhibited an adaptive antenna for MetroCell modular upgrade path called ABSS (Adaptive Antenna Beam Selection).