Stable connection but very low throughput with newer srsRAN gNB versions (v24.10 / v25.04) compared to v24.04

[vilian3688]

Description

Hello,
I’ve been testing srsRAN gNB with a Waveshare RM500U-CN 5G module, and I’ve noticed a significant performance regression between versions. The newer releases are very stable, but throughput—especially uplink—has dropped drastically compared to v24.04.

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Environment

• UE: Waveshare RM500U-CN (5G module)
• gNB versions tested:
  • ✅ v24.04 — Unstable connection (issue Assertion failure in du_processor_impl.cpp:486 when UE disconnects Environment #1395) but high throughput
  • ✅ v24.10 — Stable connection but slow throughput
  • ✅ v25.04 — Stable connection but slow throughput
• Core Network: Open5GS v2.7
• Frequency Band: n78
• gNB–RU Connection: Ethernet (wired) to RU board
• UE–RU Connection: Over-the-air via radio signal
• gNB Configuration: Same config file used across all versions
• Throughput Test Tool: iperf3

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Observed Behavior

v24.04

• Sometimes fails to attach (related to issue #1395)
• When connected, throughput is much higher:
  • TCP: UL ≈ 18 Mbps / DL ≈ 4 Mbps
  • UDP: UL ≈ 20 Mbps / DL ≈ 100 Mbps

v24.10 / v25.04

• Connection is very stable (no attach issue)
• Throughput drops drastically:
  • TCP: UL ≈ 200 Kbps / DL ≈ 1.5 Mbps
  • UDP: UL ≈ 400 Kbps / DL ≈ 100 Mbps

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Expected Behavior

Stable connection with throughput similar to v24.04.

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Additional Information

• Same configuration and Open5GS version used for all tests.
• No visible PHY or RLC errors in the gNB logs.
• The issue seems related to internal changes between versions (scheduler, buffer handling, or PHY layer).
• iperf3 used for both TCP and UDP uplink/downlink tests.

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Question

Could you please help check if there were any major changes between v24.04 and v24.10+ that could affect uplink performance?
Any guidance on debug parameters or logging that could help isolate this issue would be appreciated.