Introduced in December 2017, 5G NR Release-15 laid the foundation for ultra-fast data speeds, ultra-low latency, and connectivity to billions of IoT devices. Now, when designers design devices that will be impacted by 5G—such as smartphones, tablets, laptops, and wearables—they must consider that their devices will operate on new technologies in new frequency bands.


5G NR (5G New Radio) refers to wireless access technology between terminals and base stations on a 5G network.

5G NR presents new ways to use spectrum at sub-6 GHz and mmWave frequencies.

Sub-6 GHz focuses on expanding the scope and supporting low-latency applications such as low-speed IoT applications, digital control systems, security cameras, autonomous vehicles, and pacemakers.

mmWave frequencies enable data-intensive applications such as ultra-high-definition streaming, as they provide wider channel bandwidths that can support eMBB use cases.

5G NR reallocates some of the existing LTE bands and adds newly licensed spectrum in several bands.
Designing for mmWave frequencies up to 52.6 GHz is one of the most challenging aspects of 5G NR.

Signal impairments such as I/Q gain imbalance, phase noise, linear and nonlinear compression, and frequency errors increase with higher frequencies and wider bandwidths. This damage distorts the modulated signal, making it difficult for the receiver to accurately demodulate the signal.

Therefore, it is important to evaluate signal modulation characteristics by looking at the IQ array and identifying potential waveform distortion errors.

Designers can evaluate signal performance by measuring overall error vector magnitude (EVM), per-symbol EVM, and per-subcarrier EVM. A degraded EVM is an indicator of performance degradation and can lead to signal locking issues. The high-density modulation expected in 5G NR is reflected in the more stringent EVM requirements in the 3GPP specifications.
EVM for 256 QAM is much more difficult to achieve in design. Therefore, test solutions must use more dense modulation schemes to achieve higher levels of accuracy in measurement, verification, and troubleshooting.

Additional measures of signal performance include wideband frequency performance measured by Occupied Bandwidth (OBW), Adjacent Channel Power Ratio (ACPR), Spectrum Emissions Masks (SEM), and simulated emission masks.
These measurements provide insight into the overall power and signal quality outside the signal bandwidth.

In the next article, we will explore the third challenge: effectively deploying beam steering technologies at mmWave frequencies.

▒See the 5 Challenges 5G NR Device Designers Must Overcome
<1> Utilizing variable slot duration
<2> Increase throughput at high frequencies and wide bandwidths
6"><3> Effective use of beam steering technology at mmWave frequencies
<4> OTA testing on 5G mmWave devices
<5> Peaceful coexistence with LTE and other wireless communications