was 1.4 MHz already in Release 8. The 200 kHz bandwidth required more changes in the specifications because new channel definitions were included for the narrowband control and data channels. Cat-M supports a peak rate of 1 Mbps with full duplex and 375 kbps in half duplex. NB-IoT with 200 kHz bandwidth limits the data rates to lower values: 26 kbps in downlink and 62 kbps in uplink. Therefore, NB-IoT can only support those uses cases where the transmitted data volumes are relatively low. Cat-M and NB-IoT also allow a lower device output power: 20 dBm for Cat-M and later even 14 dBm for NB-IoT, while LTE smartphone categories use 23 dBm. One additional difference between the IoT UE categories is VoLTE capability: Cat-M can support VoLTE, while NB-IoT does not support VoLTE. Another difference is mobility capability: LTE-M supports handovers, while NB-IoT relies on cell reselections. IoT UE categories are summarized in Table 14.2. Cat-M and NB-IoT are designed to be multiplexed within the LTE carrier with other LTE traffic. Both Cat-M and NB-IoT solutions were implemented and have been widely deployed in LTE networks starting 2017. IoT uses mostly sub-1-GHz bands in order to benefit from better propagation and larger coverage areas. Cat-M was typically a soft- ware upgrade to the network, while NB-IoT required new base station hardware in some cases. Cat-M usage started mainly in the United States, while NB-IoT started in Korea. Table 14.2 loT UE categories in Releases 8-14. Release 8 Release 12 Release 13 Release 14 Cat-NB1 Cat-NB2 Cat-4 Cat-1 Cat-0 Cat-M (NB-IoT) Cat-M2 (NB-IoT) Downlink 150 Mbps 10 Mbps 1 Mbps 1 Mbps 26 kbps 4 Mbps 127 kbps peak rate (375 kbps) Uplink peak 50 Mbps 5 Mbps 1 Mbps 1 Mbps 62 kbps 7 Mbps 159 kbps (375 kbps) Number of antennas Duplex Half duplex Half duplex Half duplex Half duplex duplex duplex duplex 20 MHz 20 MHz 20 MHz 1.4 MHz 0.2 MHz 5 MHz 0.2 MHz bandwidth Transmit 23 dBm 23 dBm 23 dBm 20/23 dBm 14/20/23 dBm 20/23 dBm 14/20/23 dBm power VoLTE 14 Internet of Things Optimization C