Texas Instruments (TI) (NYSE: TXN) 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 more costly high-performance RF power amplifier components. 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.
Increased subscriber demand for wireless service, within limited licensed RF spectrum, has forced base station OEMs to adopt wideband, complex, spectrally efficient modulation schemes to increase voice and data capacity over cellular networks. These signals are more sensitive to distortion. As a result, multi-carrier PAs operate well below saturation, where they are much less efficient. RF systems engineers must compensate for this reduced efficiency by utilizing more expensive components in the RF power amplifier subsystem design.
The advanced DPD linearization technology of TI’s GC5322 wireless transmit processor significantly reduces the requirements that would otherwise be placed on the base station power amplifier. The GC5322 processes composite input bandwidths of up to 40MHz and significantly reduces the Peak-to-Average ratio (PAR) of the input signals while also improving adjacent channel leakage ratio (ACLR). The flexible DSP-based pre-distortion linearization algorithm supports multiple power amplifier architectures and emerging standards, such as CDMA2000, W-CDMA, TD-SCDMA, OFDMA (WiMAX, LTE), HSPA, and HSPA+. By optimizing the PA performance, engineers will be able to meet the cost, linearity and efficiency goals of current and future radio card architectures.
“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,” said Jagdish Rebello, Director and Principal Analyst with iSuppli. “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 highly 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.”
The GC5322, coupled with TI’s TMS320C6727 low-cost, floating-point DSP, offers basestation OEMs real-time processing power and the flexibility to modify the DPD algorithm to adapt to emerging wireless standards. The GC5322 is supported by a complete evaluation system, including high speed data converters, power solutions, clock synthesis, and high performance RF. TI’s unique total signal chain solution allows engineers to obtain measurable performance results, shorten time-to-market and remove risk from critical development programs.
“This level of integration is a true step forward in analog technology for cellular infrastructure,” said David Briggs, general manager of TI’s RF and radio products. “The significant cost reduction, improved power efficiencies and PA optimization, translates into real savings for our base station customers.”
The GC5322 adds to TI’s comprehensive analog product line targeted for wireless infrastructure applications, including high performance RF, high speed data converters, clocking, and amplifier solutions. In addition to complete analog signal chain solutions, TI also offers a line of wireless infrastructure DSPs including single and multicore devices and wireless air interface specific software libraries that enable customers to maximize the efficiency of their design, reduce development costs and speed time to market. TI leads the industry in deployment with the top eight 3G basestation manufacturers using TI products. More information: TI’s complete wireless infrastructure solutions