The advent of 5G has unveiled a new chapter for LTE evolution. LTE will gradually incorporate 2G and 3G and become an all-business fundamental network in the 5G era. LTE will also continue to enhance its capabilities and collaborate with NR in the 5G era. In June 2018, 3GPP Release 15, the first version of 5G NR standards, was frozen, marking a milestone in the communications history. In Release 15, LTE air interface is comprehensively enhanced, capable of supporting E-UTRA-NR Dual Connectivity (EN-DC) and LTE connection to 5G Next Generation Core (NGC). This allows LTE to evolve together with NR, both of which will be integral parts of the 5G era.
LTE will evolve in the following aspects: 1. More spectrum resources will be aggregated to provide a higher throughput. 2. Downlink 1024QAM, uplink 256QAM, and Massive MIMO in TM9 will be supported to achieve higher spectral efficiency. 3. Short transmission time interval (short TTI) will be introduced to reduce the latency. 4. The bearer capabilities of NB-IoT and eMTC IoT will be further enhanced to substitute 2G or 3G IoT. 5. LTE will be deeply integrated with the NR architecture to serve as the anchor for NR and support EN-DC and connection to 5G NGC.
The continuous evolution of LTE helps operators reuse investments in LTE to quickly enable 5G services. In addition, the potential of LTE networks will be fully unleashed to cope with the increasing traffic demands.