The mobile industry has taken more steps to advance the future of 5G, as the 3GPP Release 15, Standalone (SA) 5G NR standard has been finalized.

The completion of SA specifications which complements the NSA specifications, not only gives 5G NR the ability of independent deployment, but also brings a new end-to-end network architecture, enabling new business models and a new era where everything is interconnected.

Balazs Bertenyi, Chairman of 3GPP TSG RAN, said: "The freeze of Standalone 5G NR radio specifications represents a major milestone in the quest of the wireless industry towards realizing the holistic 5G vision. 5G NR Standalone systems not only dramatically increase the mobile broadband speeds and capacity, but also open the door for new industries beyond telecommunications that are looking to revolutionize their ecosystem through 5G."

Erik Guttman, Chairman of 3GPP TSG SA, adds: "The agreed completion of the stage 3 freeze milestone for the 5G standalone system has great significance. The 5G System specification has now reached its official stage of completion, thanks to the intense efforts of hundreds of engineers over the past three years. A special acknowledgment is due to those who led this remarkable effort in diverse committees. 5G promises a broad expansion of telecommunications, as an ever more central component of our economies, societies and individual activities. The 5G System opens the way for commercialization of services based on the New Radio and 5G Core Network and their advanced extensible capabilities. The new system provides the foundation for ongoing specialization for support of new business sectors, for unlike 4G and past generations, 5G supports the very specific requirements and individual service characteristics of diverse communications. Already, 3GPP activities have begun to leverage the 5G system to realize opportunities in areas such as industrial automation. This activity will intensify in the months and years to come, in increasingly many sectors, all on the foundation of the work that has been achieved on this occasion."

Besides the specifications, there are many thngs need to be done before
we see 5G networks and handsets. For example, semiconductor fabs will need to change the way that the process wafers, test engineers will have to figure out how to test, and handset designers will have to figure out how to track steered beams as people move. On top of these and other problems, wireless products will have to sell for prices close to current levels.

For example, while some 5G ICs are starting to appear, it's still unclear which processes will win for the fabrication of power amplifiers (PAs) and phased-array antennas.

"Frequencies above 6 GHz will require breakthroughs," said MACOM's Anthony Fischetti in a presentation during the recent 5G Summit at the 2018 International Microwave Symposium (IMS). "The III-V processes are different than CMOS and power is too much for GaAs at frequencies below 6 GHz." Fischetti explained how his company is coping with the different processes. For example, MACOM is partnering with STMicroelectronics to make RF devices using a GaN-on-silicon process. While such a process is possible, it's impractical at the production quantities that will be needed. The equipment needed either isn't available or is extremely expensive. He notes that MACOM currently manufactures some 50,000 CMOS wafers a week at a fab running 24/7. With today's equipment, the company would need a month to make that many GaN (III-V) wafers. "III-V fabs have to change to ramp up to the scales to today's CMOS processes."

Fischetti also noted that for a III-V process to be economically feasible, it can't have reworked wafers. The quality has to be built into the process. Plus, photolithography has to be used to shoot the images of the layers onto the wafer. Electron-beam lithography is too slow. Another issue with III-V processes is that there can't be any gold in the cleanroom. Employees must remove all gold watches and jewelry.

In addition to the process issues that 5G will bring, there are test issues. In the panel session, Loy Laskar of Maja Systems said that 80% to 90% of a bill of materials (BOM) can be taken up by IC assembly and test.

Moreover, the math needed to process the wide-bandwidth signals that mmWave frequencies bring is enormous and that takes time. At this point, test engineers don't know if they will need PC-class processors, FPGAs, or GPUs to handle the signal processing. That will take some rethinking of the way that wireless signals are processed today.

Other issues arise from high bandwidths. Because bandwidths are so wide - perhaps 100 MHz - impedances of transmission paths can vary. Test systems will have to be aware of that and compensate accordingly.

In terms of 5G networks and coverage, and in order to reduce power consumption in 5G, beam-steering with phased arrays will likely become the norm. Previous 4G antennas have been designed to be omnidirectional.

This could pose connectivity issues for consumers, who are typically do random things like moving their handsets.