In order to meet more application scenarios and market requirements, 3GPP conducted a series of enhancements to NB-IoT in Re-14 and completed the core specification in June 2017. The enhanced technology increases positioning and multicasting capabilities, provides higher data rates, paging and random access on non-anchor carriers, enhances connectivity in connection state, and supports lower UE power levels.
Positioning function: Location service is the basis of many business needs of the Internet, based on location information can be derived from a lot of value-added services. NB-IoT enhanced the introduction of OTDOA and E-CID positioning technology. The terminal can report its supported positioning technology to the network, including the positioning technology based on OTDOA, A-GNSS, E-CID, WLAN and Bluetooth. The network side selects the appropriate positioning technology according to the terminal capability and the current wireless environment.
Multicast: In order to more effectively support the message mass, software upgrades and other functions, NB-IoT enhanced the introduction of multicast technology. Multicast technology Based on LTE SC-PTM, the terminal receives the bulk of the service data through the SC-MTCH.
Data rate boost: Rel-14 introduces a new capability class UE Category NB2, the maximum transport block supported by the Cat NB2 UE is up to 2536 bits, and the uplink and downlink peak rate of a non-anchor carrier can be increased to 140/125 Kbps.
Non-Anchor Carrier Enhancement: For better load balancing, Rel-14 adds paging and random access on non-anchor carriers. So that the network can better support large connections, reducing the probability of random access conflict.
Mobility Enhancement: The CI-T EPS optimization solution for the NB-IoT control surface in Rel-14 introduces the RRC connection reconstruction and the S1 eNB RelocaTIon IndicaTIon process. When the RRC connection is rebuilt, the original base station can return the unmounted NAS data to the MME through the S1 eNB RelocaTIon IndicaTIon process and the MME to the UE through the new base station. User interface CIoT EPS optimization program in the wireless link failure, the use of LTE original switching process in the data forward function.
Lower UE power rating: Rel-14 On the basis of the original 23 / 20dBm power rating, Harvatek introduced a 14dBm UE power level. This can be used to meet some of the conditions without extreme coverage, but the need for small battery applications.
