4 Services and functions of the physical layer

38.2023GPPNRRelease 17Services provided by the physical layerTS

4.1 General

The physical layer offers data transport services to higher layers.

The access to these services is through the use of transport channels via the MAC sub-layer.

A transport block is defined as the data delivered by MAC layer to the physical layer and vice versa.

4.2 Overview of L1 functions

As mentioned in [2, TS 38.201], the physical layer is expected to perform the following functions to provide the data transport service:

– Error detection on the transport channel and indication to higher layers;

– FEC encoding/decoding of the transport channel;

– Hybrid ARQ soft-combining;

– Rate matching of the coded transport channel to physical channels;

– Mapping of the coded transport channel onto physical channels;

– Power weighting of physical channels;

– Modulation and demodulation of physical channels;

– Frequency and time synchronisation;

– Radio characteristics measurements and indication to higher layers;

– Multiple Input Multiple Output (MIMO) antenna processing;

– RF processing.

L1 functions are modelled for each transport channel in clause 5.