Supplementary downlink 5G

Supplementary Downlink ( SDL ) and Supplementary Uplink ( SUL ) are modes that allow only downlink or uplink in those bands . SDL and SUL are meant to provide additional capacity. In practice, industry looks at 5G spectrum in terms of low-band (600-700 kHz), mid-band (3-5 GHz) and high-band (26-100 GHz).

In case of Supplementary Uplink, the UE is configured with 2 UL carriers for one DL carrier of the same cell , and uplink transmissions on those two UL carriers are controlled by the network to avoid overlapping PUSCH/PUCCH transmissions in time.28 Nis 2020

Supplementary uplink (SUL) is introduced in 3GPP Rel-15 to extend the uplink coverage by providing a supplementary uplink (usually in sub-3 GHz band) . With SUL, a DL frequency band (NR frequency band) and two uplink frequency bands (one NR frequency band and one SUL frequency band) are configured in the same cell.

Supplemental Downlink (SDL) has been enabled inThird Generation partnership Project (3GPP) Release 9 as part of the evolution of High Speed Downlink Packet Access (HSDPA) . While the serving carrier (cell) for an HSDPA UE is part of paired spectrum, the SDL carrier is part of unpaired spectrum in a different band.