openairinterface5g/doc/nr-ue-design.md

Multi-threading Design

The UE_thread function in nr-ue.c is the main top level thread that interacts with the radio unit. Once the thread spawns, it starts the 'Initial Syncronization'. Once its complete, the regular processing of slots commences.

Initial Syncronization Block

graph TD
    A(Start) -->|UE_thread| B["readFrame<br/>--Reads samples worth 2 frames"]
    B --> |Tpool thread| C["UE_synch<br/>--PSS & SSS detection<br/>--PBCH decode"]
    B --> |UE_thread| D["readFrame<br/>--trash samples to unblock radio"]
    C --> |Tpool thread| E[syncInFrame<br/>--shift first sample to start of frame]
    D --> |UE_thread| E

Regular Slot Processing

graph TD
    E[syncInFrame<br/>--shift first sample to start of frame] -->|UE_thread| F["trx_read_func (slot n)"]
    F --> |Tpool thread| G["processSlotTX (slot n+4)<br/>--PUSCH encode<br/>--PUCCH encode<br/>--trx_write_func"]
    F --> |UE_thread| H["UE_processing (slot n)<br/>--PDCCH decode<br/>--PDSCH decode"]
    G --> |Tpool thread| I(Merge)
    H --> |UE_thread| I(Merge)
    I --> |Go to next slot<br/>UE_thread| F