Digital Linearization for 3G Base Station

US : TelASIC Communications announced the availability of transmit subsystems for HSDPA/ WCDMA, EVDO/cdma2000, and WiMAX base station radios using adaptive digital linearization technology tuned for Freescale Semiconductor's leading RF Power Amplifiers (PAs). A digitally linearized PA dramatically increases power efficiency and reliability over traditional analog linearization techniques, enabling lower capital and operating expenditures for base station operators.

Using Freescale Semiconductor's latest generations of high power RF LDMOS transistors, TelASIC has fine-tuned its digital solution to maximize power efficiency, achieving 45% at the output stage while maintaining 55 dB ACPR (Adjacent Channel Power Ratio) for 3G air-interfaces. The entire PA chain efficiency achieved, including driver, pre-driver and output stages, is 38% with 55 dB ACPR.

"OEMs can achieve highly efficient power amplifiers for 3G/3.5G base station radios using digital techniques such as TelASIC's adaptive digital pre-distortion (DPD), especially when optimized around Freescale's industry-leading RF power transistors," said Jim Norling, Director of Marketing at Freescale Semiconductor's RF Division. "Additionally, OEMs designing digitally linearized PAs for 3G/3.5G could also benefit from using TelASIC's DPD-friendly PA test and development system for fine tuning their Power Amplifier modules."

TelASIC's Digitally Linearized Transmit Board

TelASIC offers a Transmit Linearizer Board (TC8242) for 1-4 carrier HSDPA/WCDMA and 1-15 carrier EVDO/cdma2000 applications, based on its internally developed ICs that implement adaptive digital predistortion (DPD) technology tuned for Freescale transistors. TelASIC also offers a DPD-friendly PA test and development system (TC0003), which uses the Transmit Linearizer board along with performance analysis software, to assist designers in optimizing their DPD-friendly PA line-ups using Freescale's RF power transistors.

Remote Radio Head Applications Demand High Power Efficiency

Until now, base station OEMs have primarily been using analog solutions for Power Amplifier linearization for radio design. Radios based on analog techniques are power-hungry because of the low (8-10% typical) power efficiency. High power efficiency is a must for next-generation distributed RF network architectures where a high-capacity radio server is connected to low power-consuming and small foot-print Remote Radio Heads (RRH), eliminating the huge expenses associated with site acquisition.

TelASIC's new and unique digital solution based on Freescale's RF Transistors address the need for such high power efficiency. In addition, the TelASIC solution offers higher reliability as all components used for correcting the PA non-linearity are fully digital. The linearization process is adaptive in nature, automatically correcting for drift in PA characteristics in the field, and eliminating any need for PA tuning in the field that could cause operator down time.

"Over the next five years, one billion-plus subscribers will be migrating from yesterday's voice-centric 2G services to tomorrow's ARPU-rich TV/video/audio/data-centric 3G services. Several operators are planning to deploy Remote Radio Heads to meet high data rate, low latency, and hole-free coverage for multimedia services," said Ashis Khan, Vice President of Sales and Marketing for TelASIC Communications. "The Remote Radio Heads require ultra-efficient power amplifiers to lower costs, minimize power consumption, reduces weight, increase reliability, and eliminate the requirement for periodic PA tuning in remote locations. Digitally linearized PA solutions offered by TelASIC and Freescale enable OEMs to meet these goals in their RRH design."

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