Qorvo touts small-cell PAs, ultra-wideband linearization results at IMS

San Francisco, CA. Qorvo at IMS 2016 highlighted a variety of products and capabilities targeting cellular communications. Sumit Tomar, general manager of Qorvo’s Wireless Infrastructure business unit, said that with the advent of 5G techniques such as massive MIMO, it’s an exciting time for a semiconductor company providing RF solutions.

Tomar said he expects to see extensive activity both below and above 6 GHz, as researchers evaluate tradeoffs in range and data rates. He suggested that higher carrier frequencies may find use in extending indoor data-carrying capacities—in stadiums, for example. He further said he doesn’t expect 4G to go away—rather, 5G functions will appear on top of 4G capabilities.

Tomar highlighted two recent Qorvo innovations, including power amplifiers for small-cell base stations and, in conjunction with NanoSemi, ultra-wideband linearization results with GaN power amplifiers for wireless infrastructure.

Small-cell PAs

The new family of power amplifiers (PAs) for small-cell base stations promise to improve connectivity, expand capacity, and minimize disruptions on LTE/LTE-Advanced networks. The devices target distributed antenna systems (DAS). Systems using these PAs can eliminate the need for linearization or digital pre-distortion (DPD) correction, reducing system complexity. Qorvo’s eight new PAs cover 3GPP bands between 1.8 to 2.4 GHz and are pin-for-pin compatible.

Tomar said, “Multi-mode, multi-band small cell base stations pose significant RF challenges in terms of size, power added efficiency, and co-existence between WLAN and cellular frequency bands. Qorvo has worked closely with customers to address these RF challenges to create a portfolio of PAs, LNAs, filters, and duplexers to enable carrier aggregation in small cell base stations, and we’re pleased to add this new family of multi-stage PAs to that offering.”

Earl Lum, president of EJL Wireless Research LLC, said in a press release, “While mobile operators continue to deploy outdoor macrocell sites to increase capacity, the wireless industry is transitioning to in-building wireless solutions. LTE/LTE-Advanced drives the need to extend wireless signal coverage indoors for corporate offices, hospitals, shopping malls, and other enterprise clients. Distributed antenna systems and carrier-grade OEM small-cell solutions like Ericsson Radio Dot, Huawei LampSite, Nokia Flexi Zone, and ZTE’s Qcell are key technologies that address the ever growing in-building wireless coverage/capacity problem.”

Qorvo’s multistage PAs integrate matching in a low-cost surface-mount package to allow for compact system design. With linear performance at -47 dBc ACLR using a 20-MHz LTE signal, the TQP92xx product family provides 24-dBm average linear power, and the TQP94xx family provides 27-dBm average linear power.

Ultra-wideband linearization

Qorvo also announced, in conjunction with NanoSemi, a developer of digital linearization and compensation algorithms, that it has demonstrated industry-leading ultra-wideband linearization results with its GaN power amplifiers for wireless infrastructure.

Qorvo’s QPA2705, which Tomar described as the industry’s smallest 5-W PA, is an integrated GaN driver and GaN Doherty power amplifier with 30-dB gain, P3dB of 44 dBm, and PAE of 35% at 37-dBm average output power. It comes in a compact 6 x 10-mm surface-mount package for massive MIMO applications. Using QPA2705 integrated GaN driver and GaN Doherty power amplifier with NanoSemi’s proprietary digital compensation algorithms, the two companies have achieved the results detailed in the following table:

Tomar explained that cellular operators are enhancing wireless spectrum efficiency and boosting network capacity by adopting technologies including MIMO, active antenna systems (AAS), and LTE-Pro. By combining Qorvo’s ultra-compact, advanced power amplifier (PA) modules with NanoSemi’s digital pre-distortion (DPD) intellectual property, he said operators can implement efficient, small form-factor massive MIMO transceivers for next-generation base stations.

Tomar added, “Active antenna systems with 64 transceivers pose significant challenges to design power amplifiers with the small form factors, high efficiency, and linearity needed for multi-carrier configurations. The combination of Qorvo’s ultra-compact advanced PA modules and NanoSemi’s DPD IP enables customers to implement high efficiency, smaller form-factor massive MIMO transceivers suitable for next-generation base stations.”

Helen Kim, CEO of NanoSemi, said in a press release, “We are excited to collaborate with Qorvo and demonstrate best-in-class results with our digital compensation technology. NanoSemi’s unique approach to digital pre-distortion (DPD) and CFR enables our customers to tune their products to the sweet spot of performance, resource needs, power and targeted bandwidth.”

See related article “Qorvo at IMS debuts GaN transistors, power amplifiers.”