“Radios are challenging at any level, but with the advent of 5G, the bandwidth will become larger, the frequencies will be higher, the total radiated power will be higher, and the number of antennas will grow exponentially. Optimizing the performance of these devices while reducing size, weight and overall power consumption requirements is a daunting task. In an interview with EEWeb, Nitin Sharma, general manager of ADI’s wireless communications business unit, described the company’s latest radio platform for the 5G O-RAN ecosystem, designed to reduce time-to-market and meet the evolving needs of 5G networks.

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This article is compiled from eeweb

Radios are challenging at any level, but with the advent of 5G, the bandwidth will become larger, the frequencies will be higher, the total radiated power will be higher, and the number of antennas will grow exponentially. Optimizing the performance of these devices while reducing size, weight and overall power consumption requirements is a daunting task. In an interview with EEWeb, Nitin Sharma, general manager of ADI’s wireless communications business unit, described the company’s latest radio platform for the 5G O-RAN ecosystem, designed to reduce time-to-market and meet the evolving needs of 5G networks.

Sharma said: “O-RAN presents a unique set of challenges on the road to success. The interdependence among ecosystem players is different from traditional market structures. One vendor alone is not enough. Instead, they Co-innovation and taking collective risks must be considered and working to reduce or eliminate them. Successful deployments depend on close collaboration and openness among participants across the ecosystem. At ADI, we are committed to providing solutions from system integrators to PA suppliers. The entire ecosystem to ensure end-to-end interoperability and optimal efficiency. By working together to improve overall system performance, this helps our customers quickly create great O-RUs.”

5G Radio Platform

ADI’s radio platform includes all the core functions required for an O-RAN compliant 5G radio unit, including baseband ASICs, software-defined transceivers, signal processing and power supplies. The advanced radio platform is designed to significantly improve performance and form factor to address key power and cost challenges facing next-generation networks, while reducing customer design cycles.

5G brings new changes to the mixing band, such as an increased likelihood of aliasing or signal interference in the C-band. “If you recall the sampling standard for Nyquist signals, a Nyquist zone subdivides the spectrum into evenly spaced regions at intervals of Fs/2. Each Nyquist zone contains a copy of the spectrum of the desired signal Or its mirror image. According to the theorem, signals below and above the sampling rate, equal amounts of signals, appear superimposed on each other at the ADC output,” Sharma said. “That’s why this is important: One common receiver architecture found in base station radios is based on an analog-to-digital converter (ADC) sampling at about 3GHz to 4GHz (using 2949.12MHz is a convenient rate). It turns out that C-band frequencies and some of the most commonly used FDD bands interfere with each other when using devices based on these ADCs. This is a difficult (i.e. expensive) problem to solve. ADI employs a method to avoid this problem radio architecture and greatly simplifies the necessary filtering.”

O-RAN architecture. (Source: https://www.o-ran.org/)

Given the high-performance requirements of 5G, Sharma noted that all components become critical in these radio units. “Typically, software-defined transceivers set the benchmark for the system, but power, synchronization and clocking, PA, antenna and PHY baseband can impact overall performance. With the 8T8R radio platform, we are improving the performance of O-RAN compatible O-RUs. SWaP+C (size, weight, power + cost) metrics,” Sharma noted. Analog Devices works closely with PA partners to improve device linearity and efficiency. We also work with system integrators and test equipment developers to optimize PHY interoperability. Combine this with ADI’s portfolio of efficient, high-performance silicon solutions, and it’s a real-world example of how the O-RAN ecosystem works together. “

ADI’s reference platform will enable designers to create O-RAN compliant radios using:

ADI’s next-generation transceivers feature advanced digital front-end signal processing (DFE), digital predistortion, crest factor reduction, channel digital upconverters and channel digital downconverters for GaN PAs.

A low PHY baseband ASIC that provides a 7.2x compliant solution for LTE, 5G and NBIoT, including IEEE1588 Precision Time Protocol and eCPRI interface.

A complete clock and power chain solution.

Sharma concluded: “Over multiple product generations, ADI’s wireless technology roadmap has expanded the performance and capabilities of our market-leading software-defined transceivers. We have successively integrated important parts of the signal chain. Building on successive generations On top of that, we’ve expanded the channel count, increased bandwidth, and added important digital capabilities, all while reducing size, weight, and power consumption.”