×Jan-03-2024
Apple Inc is looking for a 4G/5G system engineer on mobility control. Based in California, USA (Bay Area or San Diego). Details Here.
Overview of physical channels
A downlink physical channel corresponds to a set of resource elements carrying information originating from higher layers. The following downlink physical channels are defined:
- Physical Downlink Shared Channel, PDSCH
- Physical Broadcast Channel, PBCH
- Physical Downlink Control Channel, PDCCH
Overview of physical signals
A downlink physical signal corresponds to a set of resource elements used by the physical layer but does not carry information originating from higher layers.
The following downlink physical signals are defined:
- Demodulation reference signals, DM-RS
- Phase-tracking reference signals, PT-RS
- Channel-state information reference signal, CSI-RS
- Primary synchronization signal, PSS
- Secondary synchronization signal, SSS
Physical resources
The frame structure and physical resources the UE shall assume when receiving downlink transmissions are defined in Resource Grid.
The following antenna ports are defined for the downlink:
- Antenna ports starting with 1000 for PDSCH
- Antenna ports starting with 2000 for PDCCH
- Antenna ports starting with 3000 for channel-state information reference signals
- Antenna ports starting with 4000 for SS/PBCH block transmission
The UE shall not assume that two antenna ports are quasi co-located with respect to any QCL type unless specified otherwise.