the new mmWave bands. Aside from physical layer design implications, the advent of the latter features significantly impact the analog/digital RF hardware system design/implementation including filters, ampli- fiers, data converters, antennas, etc. In this chapter, we will discuss the new radio spectrum, RF characteristics, implementation considerations of the NR base stations and the devices as well as the hardware technologies that are used to implement various features of the new radio. In the course of this chapter, we will discuss various types of NR base stations and their external interfaces over which the RF requirements are defined. We further explore the conducted and over-the-air (OTA) RF requirements specified by 3GPP for testing and evaluating the performance of the NR base stations and devices. 5G NR. DOI: https://doi.org/10.1016/B978-0-08-102267-2.00005-1 © 2019 Elsevier Inc. All rights reserved. 656 Chapter 5 5.1 NR Radio Parameters and Spectrum The requirement for spectrum flexibility was a key driving factor for the adoption of OFDM-based technologies in 3GPP LTE which continues to be a major driver for the NR frequency planning and deployments. The need for diverse spectrum allocations in terms of spectral bands, operation bandwidths, duplex schemes (paired and unpaired spectrum) and multiple-access schemes emerged during the 3G and 4G deployments and has led to one of the most distinctive characteristics of 5G NR, which supports a large and diverse spectrum from 450 MHz to 52.6 GHz (and up to 100 GHz in future releases). The maximum fre- quency currently under study in ITU-R is 86 GHz (see Fig. 5.1). The NR supports operating bandwidths of 5 MHz to 3.2 GHz for both paired and unpaired spectrum as well as supple- mentary downlink (SDL) or supplementary uplink (SUL) carriers. The NR defines various frequency bands within the 5G spectrum. Although the boundaries of the NR frequency bands can vary in different countries and regions, it must be possible to efficiently allocate RF carriers at positi