 17 considering ranges up to 114 GHz Higher bandwidths with up to 100 MHz on lower frequency bands (below 7.125 GHz) and up to 400 MHz with above-24-GHz bands Shorter latency down to the sub-millisecond level For these reasons, higher subcarrier spacing (resulting in shorter symbol duration) was employed, especially toward the higher frequency bands and where a larger band- width was possible. It was decided to specify a set of subcarrier spacings that represents a power-of-two relationship to the LTE subcarrier spacing. This approach was selected to facilitate efficient multi-technology support with platforms using both LTE and 5G. Compatible sampling rates make multimode implementation more cost efficient. The subcarrier spacings range from 15 kHz all the way up to 240 kHz (for data up to 120 kHz), with parameters as shown in Table 6.1. The smaller subcarrier spacings are intended to be used below 7.125 GHz bands (Frequency Range 1, FR1), while the higher subcarrier spacing are intended for above 24 GHz (FR2) due to the better tolerance for phase noise with higher frequency bands. The border of FR1 was lifted from 6 GHz to 7.125 GHz only as late as December 2018 to cover the extension of the unlicensed 5 GHz frequency bands to above 6 GHz range in some regions. The lowest part of the FR1 range is as low as 410 MHz. The basic approach is to reduce the OFDM symbol duration in the time domain, which increases the subcarrier spacing. For example, increasing the symbol rate to twice the LTE symbol rate leads to the 30 kHz subcarrier spacing. If one retains the same number of symbols per sub-frame, then the duration of the transmission time interval (schedul- ing interval) would be 0.5 ms. The use of N as a multiplier, and staying with powers 6 5G Physical Layer Table 6.1 5G L1 subcarrier spacing values. Subcarrier spacing (kHz) Symbol duration (us) Nominal CP (us) 1.205 Nominal max carrier BW (MHz) Max FFT size Min scheduling interval (symbols) Min scheduling interval (slots) Min scheduling interval (ms) 0.125 of 2,