Hello,
I managed to achieve a successful cell attach and registration between a LimeSDR-mini acting as eNB and a LimeNET-micro acting as UE, both running on the same computer.
Getting srsLTE to work was not easy, it seems a regression was introduced this year in the eNB codebase -producing SOAPY_SDR_TIMEOUT stream errors, so I had to use an earlier version of the code.
Software versions:
SoapySDR - tag 0.7.1
LimeSuite - commit 1b0309b385547db64ef116618c774c8ce62de0d5
srsLTE - commit d045213fb9cbf98c83c06d7c17197a9dcbfddacf
Configuration: EARFCN was chosen within the amateur radio band 2305 - 2400 MHz.
time_adv_nsamples was set to 70 for both eNB and UE.
Number of PRBs selected for eNB was 15 to fit within LimeNET-micro USB2.0 bandwidth.
A minor patch was necessary for the Soapy driver of srsLTE. Unfortunately the default code does not allow us to choose between multiple devices so I made a 4 line hack to enable the UE to run on the same machine as the eNB:
diff --git a/lib/src/phy/rf/rf_soapy_imp.c b/lib/src/phy/rf/rf_soapy_imp.c
index 8aebf8be9..4ecaa7b54 100644
--- a/lib/src/phy/rf/rf_soapy_imp.c
+++ b/lib/src/phy/rf/rf_soapy_imp.c
@@ -297,8 +297,14 @@ int rf_soapy_open_multi(char* args, void** h, uint32_t num_requested_channels)
}
printf("\n");
}
+ SoapySDRDevice* sdr;
+
+ if (args && (strstr(args, "nextdev"))) {
+ sdr = SoapySDRDevice_make(&(soapy_args[1]));
+ } else {
+ sdr = SoapySDRDevice_make(&(soapy_args[0]));
+ }
- SoapySDRDevice* sdr = SoapySDRDevice_make(&(soapy_args[0]));
if (sdr == NULL) {
printf("Failed to create Soapy object\n");
return SRSLTE_ERROR;
Logs below show successful attach and IP assignment by EPC:
=======================================
Initial UE message: LIBLTE_MME_MSG_TYPE_ATTACH_REQUEST
Received Initial UE message – Attach Request
Attach request – IMSI: 001010123456789
Attach request – eNB-UE S1AP Id: 1
Attach request – Attach type: 1
Attach Request – UE Network Capabilities EEA: 11110000
Attach Request – UE Network Capabilities EIA: 01110000
Attach Request – MS Network Capabilities Present: false
PDN Connectivity Request – EPS Bearer Identity requested: 0
PDN Connectivity Request – Procedure Transaction Id: 1
PDN Connectivity Request – ESM Information Transfer requested: false
Downlink NAS: Sending Authentication Request
UL NAS: Received Authentication Response
Authentication Response – IMSI 001010123456789
UE Authentication Accepted.
Generating KeNB with UL NAS COUNT: 0
Downlink NAS: Sending NAS Security Mode Command.
UL NAS: Received Security Mode Complete
Security Mode Command Complete – IMSI: 001010123456789
Getting subscription information – QCI 7
Sending Create Session Request.
Creating Session Response – IMSI: 1010123456789
Creating Session Response – MME control TEID: 1
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_CREATE_SESSION_REQUEST
SPGW: Allocated Ctrl TEID 1
SPGW: Allocated User TEID 1
SPGW: Allocate UE IP 172.16.0.2
Received Create Session Response
Create Session Response – SPGW control TEID 1
Create Session Response – SPGW S1-U Address: 127.0.1.100
SPGW Allocated IP 172.16.0.2 to IMSI 001010123456789
Adding attach accept to Initial Context Setup Request
Initial Context Setup Request – eNB UE S1AP Id 1, MME UE S1AP Id 1
Initial Context Setup Request – E-RAB id 5
Initial Context Setup Request – S1-U TEID 0x1. IP 127.0.1.100
Initial Context Setup Request – S1-U TEID 0x1. IP 127.0.1.100
Initial Context Setup Request – QCI 7
Received Initial Context Setup Response
E-RAB Context Setup. E-RAB id 5
E-RAB Context – eNB TEID 0x4f0003; eNB GTP-U Address 127.0.1.1
UL NAS: Received Attach Complete
Unpacked Attached Complete Message. IMSI 1010123456789
Unpacked Activate Default EPS Bearer message. EPS Bearer id 5
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_MODIFY_BEARER_REQUEST
Sending EMM Information
Received UE Context Release Request. MME-UE S1AP Id 1
There are active E-RABs, send release access bearers request
Received GTP-C PDU. Message type: GTPC_MSG_TYPE_RELEASE_ACCESS_BEARERS_REQUEST
UE is ECM IDLE.
Received UE Context Release Complete. MME-UE S1AP Id 1
UE is not ECM connected. No need to release S1-U. MME UE S1AP Id 1
UE Context Release Completed.
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