Introduced in December 2017, 5G NR Release 15 laid the foundation for ultra-fast data speeds, ultra-low latency, and connectivity for billions of IoT devices. Designers now need to consider that their devices, including smartphones, tablets, laptops, and wearables that will be impacted by 5G, will operate in new frequency bands and with new technologies.


To comply with the 5G NR standard, devices must operate in different operating models across different frequency bands.

5G NR must operate in adjacent cellular bands, sometimes even within the same spectrum as other wireless communication systems, such as Wi-Fi, Citizens Broadband Radio Service (CBRS), military, and satellite services.

Shared spectrum can use a collection of channels in unlicensed spectrum to expand device performance and throughput. LTE unlicensed (LTE-U), Licensed Assisted Access (LAA), and MulteFire allow LTE operation in unlicensed spectrum.

LAA uses the 4G network as an anchor and uses a Listen Before Talk (LBT) method to ensure no other tasks are performed before transmitting data using auxiliary channels. Because LAA uses multiple protocols in the same frequency band, it employs multiple permutations, requiring careful coexistence design and testing.

5G NR, operating in mid-band frequencies (3.3–4.2 GHz, 3.3–3.8 GHz, and 4.4–5 GHz), may cause interference with adjacent IEEE 802.11ac and 802.11ax Wi-Fi networks (2.4 GHz and 5 GHz), as well as other Industrial, Scientific, and Medical (IMS) bands. Therefore, if each band is not properly filtered, emissions due to harmonics, intermodulation spurs, and spectral regrowth can affect wireless transmissions in these bands.
A constellation diagram simultaneously displays phase and amplitude information. Measuring a signal with a vector signal analyzer and viewing the results in a constellation diagram can reveal signal interference and distortion issues.

The EVM of isolated signals and the EVM per subcarrier can predict the likelihood of coexistence in crowded frequencies. Wideband frequency measurements such as ACLR and SEM can help identify potential interference between signals.

5G NR will need to coexist with existing commercial wireless infrastructure, as well as military and non-military radar and satellite signals. The 5G NR mmWave operating band in Frequency Band 2 (FR2) overlaps with Fixed-Satellite Services (FSS) ground station uplink (27.5–29.5 GHz) and downlink (37.5–40 GHz). In this scenario, primary users can have priority in the frequency band. 5G NR devices must sense their environment and adapt their behavior based on the policies of their location.

▒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