UE does not connect - RAN550 split 7.2 #398
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Hi, i trying to use split 7.2 setup, i am getting a locked from the RU and everything seems ok, However, UEs does not connects. anyone can help? am i missing something? Issue Setup and connections:
logs DU Config RU Config 4x2 TDD pattern RU status Pcap |
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Answered by
khooi8913
Jan 11, 2024
Replies: 6 comments 4 replies
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Have you looked at the RU KPIs? Do all packets arrive on time? |
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1 reply
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Yes, i do have RX on time |
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Hi @AzeezEbrahim , I believe we are facing a similar issue, see #389. Based on our understanding, this is because the current v0.8.1 RU firmware defaults to 100MHz bandwidths and always expects 273 PRBs around your configured center frequency (3.55GHz). Your current DU configuration, i.e., 20MHz, will only generate IQ samples for PRBs #0-50, which is at the lower part of your spectrum (around 3.5-3.52GHz) and does not match your broadcasted ARFCN. (Please, correct my understanding if I am wrong) If you change back the config to use 100MHz, it should work. |
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Answer selected by
AzeezEbrahim
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I would also try using 100 MHz bandwidth, update to the latest version, follow the RU application note, and if still fails send logs in info |
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1 reply
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Note: i have change the PRACH configuration Index in the RU side as well from 0xE to 0x7, it is not mentioned in the srs tutorial, but any way it does not matter same issue . logs config RU side tssi rssi |
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The TDD pattern you configured in the RU is 6-3 while the one configured in the DU is 7-2, as such, remove the You didnt mention what type of UE you are using, but it would be good to know if the UE finds the cell, then if it PRACHes or not. As packets are arriving to the RU, set the OFH layer log level to warning to avoid spamming the log and set the mac/scheduler layers to debug, then check if you receive a PRACH preamble in the DU from the UE and then you should see sending Random Access Response (RAR). Once this works, look for msg3 which will be the first PUSCH transmission in the log. |
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0 replies
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i changed the LOG_INFO "Set expected RU PRACH Configuration Index (C0322)" to the default value, increased the channel bandwidth to 100 Mhz, and make the default TDD values and it worked ! Thanks @khooi8913 @faluco @ismagom |
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On the RAN 550 did you have to enable the aux port for ptp? |
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@AzeezEbrahim I'm also trying to use bentel 650 RU with srsRAN project. The TDD pattern i'm using is 7-2 on both DU and RU side. The TX_TOTAL field is showing as 0 in my case also. Means, no uplink messages are flowing. The configuration file is as same as the one you are using (du and ru mac addresses will change). Im using 100MHz bandwidth. Im using an external GNSS clock for RU synchronization. The problem I'm facing here, the UE is unable to regsiter to the core network. Im using samsung s22 mobile. UE is able recognize the network but not registering. How did you solve this problem? @ismagom @khooi8913 @faluco. kindly help. how to make the uplink messages to flow? All the configurations and logs are same on my side. That's why I am not sharing them here. |
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@abcd11abcd @AzeezEbrahim I am also facing the same issue with RAN 650. The COTS UE can scan the network but cannot attach. Were you able to fix this issue? |
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Hi @AzeezEbrahim , I believe we are facing a similar issue, see #389.
We managed to resolve it earlier and get it to work.
Based on our understanding, this is because the current v0.8.1 RU firmware defaults to 100MHz bandwidths and always expects 273 PRBs around your configured center frequency (3.55GHz). Your current DU configuration, i.e., 20MHz, will only generate IQ samples for PRBs #0-50, which is at the lower part of your spectrum (around 3.5-3.52GHz) and does not match your broadcasted ARFCN. (Please, correct my understanding if I am wrong)
If you change back the config to use 100MHz, it should work.
Or, try using 634548 for your ARFCN, and see if it works for 20MHz.