The LTE air interface physical layer offers data transport services to higher layers. The access to these services is through the use of a transport channel via the MAC sub-layer. The physical layer is expected to perform the following functions in order 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
- Transmit Diversity (TX diversity)
- Beamforming
- RF processing
Protocol specification
3GPP TS 36.201 - Evolved Universal Terrestrial Radio Access (E-UTRA); LTE physical layer; General description
3GPP TS 36.211 - Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation
3GPP TS 36.212 - Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding
3GPP TS 36.213 - Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures
3GPP TS 36.214 - Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer; Measurements