The transition from 4G to 5G brings a variety of benefits, notably an increased data rate and mobile broadband network capacity. However, system design engineers will need to adapt to the latest 5G new radio (NR) standard which was completed in June 2018, writes Ken Karnofsky, a senior strategist for Signal Processing Applications at MathWorks.
While the standard was a long time coming for the industry and a huge tick in the box for its personnel, it presents a number of challenges. For instance, compared to 4G, 5G will operate on different radio spectrum frequencies, connect many more devices to the internet, minimise delays, and deliver ultra-fast speeds.
5G: the next stage of connectivity
As 5G will need to operate at higher millimetre wave (mmWave) frequencies, it will require different baseband algorithms and radio architectures to contain cost and accomplish performance goals. The 5G NR standard introduces significant changes to the physical layer of mobile communication systems requiring baseband modems to implement flexible algorithms to achieve the high-speed, high-capacity, and low-latency goals of 5G. The design of the receivers in base stations and mobile devices will need to be changed – this means a significant impact to the testing strategy for all components in a 5G NR system.
System design engineers must have a working knowledge of the new standard specifications as well as the proficiency to design the highly integrated 5G radio technology, which comprises RF, antenna, DSP (Digital Signal Processing), control logic, hardware, and software. They also need the latest methods to verify that components will work together and eliminate the problems that lead to expensive hardware failures and delays to project run-times.
Engineering organisations that have separate workflows for doing baseband, RF front end, and antenna design will likely struggle to keep pace with their peers. For example, achieving power efficiency and linear performance across wide bandwidths in the RF front-end, including power amplifiers is another obstacle that needs to be overcome. This requires adaptive DSP techniques such as DPD (digital predistortion), which often must be designed and verified in simulation before the RF hardware is even available.
Use outside assistance where necessary
The increased complexity of 5G NR is prompting development teams to look to field-programmable gate array (FPGA) prototypes and test beds to validate designs. This is a significant hurdle for many teams that lack experience with FPGA development workflows and register-transfer level (RTL) implementation of signal processing and communications algorithms. For a typical R&D group that consists of engineers with strong signal processing and algorithm development backgrounds but relatively little experience with hardware implementation, it is often difficult to execute these radio prototypes and testbeds without outside assistance.
5G radio and network designs also need to account for several effects as a result the use of mmWave frequencies. These now make it essential for designers to characterise RF signal propagation channels in various outdoor and indoor scenarios early in the R&D process. Higher frequencies are essential to transmitting information at ultra-fast rates, but there is an unwanted side-effect that they don’t travel as far and are easily absorbed by the atmosphere, terrain, and other objects.
Utilise the right tools
It is crucial for designers to utilise tools that enable modelling and simulation of the critical 5GNR technologies and ensure conformance to 5G NR. Fortunately, there are new tools available that help engineers efficiently explore algorithms and architectures, optimise system performance, identify critical problems in simulation, and automate hardware implementation and testing on COTS (commercial off-the-shelf) or custom hardware.
Technology that provides 5G-compliant waveforms, algorithms, and end-to-end reference models can simplify the process of design space exploration, design verification, and conformance testing.
Harness modelling and simulation
Fortunately, modelling and simulation will save organisations a significant amount of time and money and are both key to smarter design practice. The fundamental benefit though is that as the specifications and engineering changes are coming in to the design teams, they can iterate on their designs quickly – they’re able to ensure that their designs can support the new changes. And then to validate it, they can quickly take the new version of what they are working on and deploy it in a radio test bed.
Designers can now verify their projects using simulation and modelling tools, rather than waiting for expensive and time-consuming lab and field tests. The models can be used as a reference for implementation and help to automate testing in order to verify that designs function correctly throughout the development process. Instead of waiting for expensive and time-consuming lab and field tests, modelling tools allow designers to verify their projects using simulation. The models become something of a blueprint for implementation, and they can help verify that designs function correctly throughout the development process via automated testing.
