Wifi Revolution

Texas Instruments (News - Alert) (TI) has introduced a single-chip wireless transmit processor that combines digital upconverter (DUC), crest factor reduction (CFR), and digital pre-distortion (DPD) linearization functions.

 

The GC5322 device increases the efficiency of multi-carrier power amplifiers (PAs) in the RF transmit signal chain and eliminates the need for costly high-performance RF power amplifier components, according to the company.

 

Company officials pointed out that this enables basestation OEMs to achieve power efficiencies of 25 percent or more for Class AB PAs and reaching 40 percent or more for Doherty PAs.

 

Officials also explained that increased subscriber demand for wireless service, within limited licensed RF spectrum, has forced basestation OEMs to adopt wideband modulation schemes to increase voice and data capacity over cellular networks.

 

As these signals are more sensitive to distortion, multi-carrier PAs operate well below saturation, where they are much less efficient, according to officials. Also, RF systems engineers must compensate for this reduced efficiency by utilizing more expensive components in the RF power amplifier subsystem design.

 

Officials said that the advanced DPD linearization technology of TI’s GC5322 wireless transmit processor significantly reduces the requirements that would otherwise be placed on the basestation power amplifier.

 

The GC5322 processes composite input bandwidths of up to 40MHz and reduces the Peak-to-Average ratio (PAR) of the input signals while also improving adjacent channel leakage ratio (ACLR).

 

In addition, officials said, the DSP-based pre-distortion linearization algorithm supports multiple power amplifier architectures and emerging standards, such as CDMA2000, W-CDMA, TD-SCDMA, OFDMA (WiMAX, LTE (News - Alert)), HSPA, and HSPA+.

 

“As power demands, spectral masks, and EVM requirements become increasingly difficult to meet, basestation OEMs are finding it challenging to design new transmitter systems and still meet BOM cost targets, power dissipation, and performance goals,” Jagdish Rebello, director and principal analyst at iSuppli, said in a statement.

 

He also said that the level of integration offered by TI's GC5322 transmit processor should not only reduce design complexity and power consumption, but will also deliver high power efficiencies and ACLR performance from a single integrated monolithic semiconductor device.

 

“This will allow OEMs to 'future proof' their design in the event that new standards or performance requirements become design criteria,” he added.

 

The GC5322 is supported by a complete evaluation system, including high speed data converters, power solutions, clock synthesis, and high performance RF.

 

“This level of integration is a true step forward in analog technology for cellular infrastructure,” said David Briggs, general manager of RF and radio products at TI. “The significant cost reduction, improved power efficiencies and PA optimization, translates into real savings for our basestation customers.”

 

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