Five Challenges 5G NR Device Designers Must Overcome <4> OTA Testing on 5G mmWave Devices
Published2019.03.01 09:01Currently, designers conducting over-the-air (OTA) testing on 5G mmWave components and devices use cable connections to perform most sub-6 GHz RF performance tests. For 5G, low-frequency testing is similar to 4G, but mmWave requires a wireless test solution, including:
▲RF performance - minimum signal quality ▲Demodulation - data processing performance ▲Radio resource management (RRM) - initial access, handover, and mobility ▲Signaling - upper layer signaling procedures
A prototype 5G NR smartphone with its antenna array positioned close to the outside.
Designers typically conduct near-field and far-field radiation testing of their devices. While far-field testing methods are traditionally the most comprehensive, they present several challenges at mmWave frequencies. As the operating frequency increases and the size of the radiating antenna increases, the distance increases, resulting in greater path loss, making it difficult to perform accurate radiation measurements.
For example, a 15cm radiating antenna operating at 28GHz has a long-range range of 4.2m and a path loss of 73dB. Due to the high operating frequency, conventional long-range testing methods require a large amount of space and suffer from high path loss, making accurate and repeatable over-the-air measurements unfeasible.
Long-distance test distance and path loss results during OTA measurements
Test vendors and 3GPP are studying Direct Far-Field (DFF), Indirect Far-Field (IFF), and Near-field to Far-field TransFormation (NFTF) test methodologies to determine the appropriate OTA test method for device and base station conformance testing.
Recently, 3GPP approved the Compact Antenna Test Range (CATR) for device RF performance testing. This OTA test method can perform measurements on the transmit power, transmit signal quality, and spurious emissions of a radiating transmitter with much lower path loss than traditional long-distance test chambers.
As 5G NR evolves, designers can reduce development time and the risk of costly rework by regularly reviewing 3GPP-approved OTA test methods and test vendor solutions.
In the next article, we will explore the fifth challenge: peaceful coexistence with LTE and other wireless communications.
▒See the 5 Challenges 5G NR Device Designers Must Overcome
<1> Utilizing variable slot duration
<2> Increase throughput at high frequencies and wide bandwidths
<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
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5 Challenges 5G NR Device Designers Must Overcome <1> Utilizing Variable Slot Duration
5G NR refers to the wireless access technology between terminals and base stations on a 5G network. 3GPP established the NR standard with the goal of providing wireless access technology by integrating eMBB, URLLC, and mMTC, which are usage scenarios for IMT-2020 technology. Additionally, 5G NR Release-15 defined specifications to support eMBB and URLLC. In the ICT industry, the emergence of something new means that designers have more work to do. Design teams utilizing 5G NR face increasingly complex challenges and a greater number of issues. To implement 5G NR, device designers must overcome five key challenges.
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Five Challenges 5G NR Device Designers Must Overcome <2> Increasing Throughput at High Frequency and Wide Bandwidth
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Five Challenges 5G NR Device Designers Must Overcome <3> Effectively Using Beam Steering Technology at mmWave Frequencies
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