В принципе, по дальности обещали не хуже, а лучше GPRS'а. Взято по ссылке: https://arxiv.org/pdf/1802.04222.pdf
The downlink of NB-IoT is based on OFDMA, with 15kHz subcarrier spacing, and reuses the same OFDM numerology as LTE. Both single-tone and multi-tone are supported in the uplink. Multi-tone is based on SC-FDMA with 15kHz subcarrier spacing. With single-tone, sub-carrier spacing can be 15kHz or 3.75kHz. NB-IoT achieves a 20 dB improvement over GPRS, giving a maximum coupling loss of 164dB.