NG-RAN and 5G-NR

55G-NR Radio Interface – Operations on the Frequency Bands

5.1. Operations on the frequency bands

Operations on the 5G-NR and 4G-LTE (Long-Term Evolution) frequency bands make it possible to increase cell coverage and/or improve data rate transmission on the UL (Uplink) and the DL (Downlink).

DSS (Dynamic Spectrum Sharing) consists of dividing the 4G FDD frequency band into two sub-bands, a 4G sub-band and a 5G sub-band. The 4G and 5G bandwidths are dynamically controlled by the radio node. Dynamic Spectrum Sharing is a technology that allows the deployment of both 4G LTE and 5G-NR in the same frequency band.

Carrier Aggregation (CA) consists of adding different 5G-NR radio channels. The 5G-NR specification defines two different approaches for informing the UE (User Equipment) about the scheduling for each band: a separate PDCCH for each carrier or a common PDCCH for multiple carriers (cross-carrier scheduling).

SUL (Supplementary Uplink) mode allows the addition of a low frequency radio channel. This channel is dedicated only for transmissions on the uplink direction. SUL aims to improve the uplink cell coverage. SUL mode differs from carrier aggregation since the mobile is controlled to transmit data on the PUSCH channel or signaling in the PUCCH channel either on the SUL band or on the traditional paired band, but not in both bands simultaneously.

Dual connectivity consists of operating two radio nodes simultaneously. Dual connectivity can take place on two different MR-DC ...