What are the possible causes for an Access Failure in UMTS?

• Missing Neighbors
• Poor Coverage
• Pilot Pollution / Spillover
• Poor Cell Reselection
• Core Network Issues
• Non – availability of resources. Admission Control denies
• Hardware Issues
• Improper RACH Parameters
• External Interference

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Ericsson Parameters to make Handover Easier

What can we try to improve when access failure is high?

When access failure is high we can try the following to improve RACH performance:

• Increase maximum UE transmit power allowed: Max_allowed_UL_TX_Power.
• Increase power quickly: power_Offset_P0.
• Increase number of preambles sent in a given preamble cycle: preamble_Retrans_Max.
• Increase the number of preamble cycles: max_Preamble_Cycle.
• Increase number of RRC Connection Request retries: N300.

Know What are the Possible Reasons for Access Failure in UMTS?