1. 15 Feb, 2024 3 commits
    • batuhanduyuler's avatar
      N2 Handover Target gNB Implementation · d75a1097
      batuhanduyuler authored
      Handover Request Message Processing
      	- AMF selection respect to GUAMI
      	- UE Context Creation in CU - NGAP
      	- UE Context Setup Request with HO Preparation Information according to F1AP Spec
      
      UE Context Setup Request Processing
      	- If HO Preparation Information Exists, DU process this message in another function
      	- Cell Group Configuration is created from target gNB's initial cell group. Then it is updated using UE Capability
      	- Reconfiguration with sync IE is prepared similar to the used one for NSA
      
      nr_pdcp_config_set_security function signature is changed and security_mode_completed input is added because from beginning we want to set pdcp_entity's security mode completed flag to true in case of handover.
      Handover Request Acknowledge message preparation is done.
      After reception of RRC Reconfiguration Complete message on target gNB; Handover Notify Message is triggered
      d75a1097
    • batuhanduyuler's avatar
      N2 Handover Source gNB Implementation · 10629df5
      batuhanduyuler authored
      - Triggering the Handover
      	- gNB finds the best neighbour (only RSRP based)
      	- gNB decides triggering the HO according to condition
      		- bestRsrp > servingCellRSRP + HO Margin
      		- HO Margin is an optimization parameter
      		- For now HO Margin set to 0.
      
      	- gNB prepares the current RRC Reconfiguration and binds to Handover
      Preparation Information
      	- gNB sends NGAP Handover Required Message towards AMF
      
      - Reception of Handover Command Message on CU
      	- Parsing of the message
      	- gNB extracts the target gNB's RRC Reconfiguration from Handover Command
      	- Wraps the target gNB's RRC Reconfiguration within DL DCCH Message
      	- Prepares F1AP UE Context Modification Message
      	- Sets Transmission Action Indicator to stop
      	- Sends the RRC Reconfiguration with UE Context Modification
      - Reception of UE Context Modification on DU
      	- Pushes to RRC reconfiguration to RLC
      	- transmission_stop flag is added under UE_sched_ctrl
      	- if UE_sched_ctrl is true, gNB stops scheduling of the UE
      	- DU sends UE Context Modification Response
      10629df5
    • batuhan duyuler's avatar
      Neigbourcell Configuration - Measurement Configuration for Inter gNB - N2 Handover · 9957f806
      batuhan duyuler authored
      - NeighbourCell and Measurement Configurations are prepared.
      
      NeighbourCell Configuration includes:
      	- neighbour_gNB_ID (This is needed for AMF to identify gNB exists in it's context
      	- neighbour_nr_cell_id (This is needed for target gNB)
      	- neighbour_physical_cellId (This is needed for UE in the meas report)
      	- neighbour_absoluteFrequencySSB (This is needed for UE in meas report)
      	- neighbour_subcarrierSpacing (This is needed for UE in meas report)
      	- neighbour_mnc (This is needed for AMF)
      	- neighbour_mcc (This is needed for AMF)
      	- neighbour_mnc_length (This is needed for AMF)
      	- neighbour_tracking_area_code (This is needed for AMF)
      
      NR Measurement Event Configuration Includes:
      	- enableA2 & enableA3 (gNB activates the event reporting according to these vars)
      	- thresholdA2 & A2_TTT (configurable reporting parameters)
      	- thresholdA3 & A3_Hysteresis & A3_TTT (configurable reporting parameters)
      
      - These parameters are read in the configuration parsing part and written under RRC structure
      - Event Based Measurement Configuration is prepared according to enableA3 parameter.
      - Measurement Configuration of UE is cloned under UE Context. When a measurement report comes,
      looping through the UE's meas config and matching the measIDs. With this measID, report configs
      extracted and processing in different ways.
      9957f806
  2. 14 Feb, 2024 3 commits
  3. 13 Feb, 2024 8 commits
  4. 12 Feb, 2024 17 commits
  5. 09 Feb, 2024 9 commits