5G NR Release-15, introduced in December 2017, laid the foundation for very fast communication speeds, very low latency, and connectivity with billions of IoT devices. Now, when designers create devices that will be under the influence of 5G, such as smartphones, tablets, laptops, and wearables, they must consider that the devices they design will operate using new technologies in new frequency bands.


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

3GPP established the NR standard with the goal of providing wireless access technology by integrating the performance requirements of IMT-2020 core technologies and three use scenarios: enhanced Mobile Broadband (eMBB), Ultra Reliable and Low Latency Communications (URLLC) for end-to-end data transmission, and massive Machine Type Communications (mMTC).

Accordingly, 5G NR Release-15, introduced in December 2017, laid the foundation for very fast communication speeds, very low latency, and connectivity with billions of IoT devices. The new physical layer standards define flexible air interfaces to support various use cases that will occur on 5G networks.

Now, when designers design devices that will be affected by 5G, such as smartphones, tablets, laptops, and wearables, they must consider that the devices to be designed must operate with new technology in new frequency bands.

5G NR Release-15 defined specifications to support eMBB and URLLC. This enables high data throughput for high-definition video and movie streaming, as well as low latency for remote-controlled drones and VR applications.

The emergence of something new in the ICT industry means that the workload for designers has increased accordingly. More complex and numerous challenges await design teams utilizing 5G NR.

The five challenges that device designers must overcome to implement 5G NR are as follows.

1. Optimizing Performance Using Scalable Numerology
2. Supporting higher throughput through carrier aggregation, mmWave frequencies, and wide bandwidth
3. Effectively Utilizing Beam Steering Techniques at mmWave Frequency
4. Perform OTA testing on 5G mmWave components and devices
5. Realizing peaceful coexistence with LTE and other wireless communications

Companies that overcome all these challenges will be able to shorten the time-to-market for 5G NR devices. First, let's look at the first task.


Optimizing Performance Using Scalable Numerology
Performance optimization using scalable numerology is a 5G NR feature that provides flexible resource allocation to support various use cases that may occur across various frequency bands.

Here, numerology is a waveform parameter function that includes subcarrier intervals and symbol times.
The subcarrier spacing is adjusted from 15 kHz to a maximum of 120 kHz, and as the subcarrier spacing widens, the slot length shortens, reducing the slot duration as shown in <Figure 1>. The variable slot duration adapts more easily to channel characteristics such as frequency range, phase noise, and delay spread.

Scalable subcarrier spacing and slot durations in the frame structure enable high-throughput mmWave operation, high-reliability IoT services, low latency, and error-free applications.

In addition, 5G NR can use mini slots (also known as mapping type "B") to initiate transmission anywhere within the slot, thereby enabling the rapid delivery of ultra-low latency payloads.

However, this scalable numerology increases the complexity of testing. More permutations are required to test various use cases. Consider a use case for the maximum throughput of 28 GHz. How a designer allocates resources within a frame affects how and when the device transmits and receives, and influences overall device performance.
If you use tools such as Keysight's Protocol R&D toolset, you can model resource allocation and execute scripts to test and optimize device performance under various conditions. The designer can model parameters such as the number of slots per frame and the order and number of symbols assigned to downlinks and uplinks within the frame.

In the next article, we will look at the second challenge: supporting higher throughput through carrier sets, mmWave frequencies, and wide bandwidth.

View the 5 Challenges 5G NR Device Designers Must Overcome
<1> Utilizing Variable Slot Duration
<2> Increasing throughput at high frequencies and wide bandwidths
<3> Effectively Using Beam Steering Technology at mmWave Frequency
<4> Testing OTA on 5G mmWave Devices
<5> Peaceful coexistence with LTE and other wireless communications