[srslte-users] Get SIBs at wrong places

[林 小涵]

Hi, everyone:
    I have met some problems when trying to decode some optional SIBs. I modified pdsch_ue.c and run pdsch_ue only with parameter "-f". I have successfully decoded SIB1, and get the schedulingInfoList like this:

"schedulingInfoList": [
  {
    "si-Periodicity": "rf8",
    "sib-MappingInfo": [
      "sibType8"
    ]
  },
  {
    "si-Periodicity": "rf16",
    "sib-MappingInfo": [
      "sibType3"
    ]
  },
  {
    "si-Periodicity": "rf32",
    "sib-MappingInfo": [
      "sibType5"
    ]
  },
  {
    "si-Periodicity": "rf64",
    "sib-MappingInfo": [
      "sibType6"
    ]
  }
]

and I am using the following code to decode other SIBs (by referening to https://www.sharetechnote.com/html/BasicProcedure_LTE_SIB_Scheduling.html):
ShareTechnote<https://www.sharetechnote.com/html/BasicProcedure_LTE_SIB_Scheduling.html>
LTE Basic Procedure Go Back To Index Home : www.sharetechnote.com. SIB Scheduling . In LTE, MIB, SIB1, SIB2 is mandated to be transmitted for any cells. Since many of the SIB are transmitted, it should be transmitted in such a way that the location (subframe) where a SIB is transmitted should not be the same subframe where another SIB is transmitted.
www.sharetechnote.com




                int x = (n_decode - 1) * win_len;
                int a = x % 10;
                int sfn_e = floor(x/10);
//                printf("x=%d, a=%dm sfn_e=%d\n", x,a,sfn_e);
                if ((sfn % si_periodicity[n_decode-1])==sfn_e && sf_idx == a) {
                  printf("trying to decode other sibs, subframe=%d, sf_idx=%d, sfn=%d, si_periodicity=%d, sfn_e=%d\n", a, sf_idx, sfn, si_periodicity[n_decode-1], sfn_e);
                  decode_sib = true;
                }

And I can decode some optional SIBs, but with a wrong schedule.

For example,
First, I get SIB2 and 8 at the correct schedule, but then I get SIB5 when the log shows:

trying to decode other sibs, subframe=0, sf_idx=0, sfn=1042, si_periodicity=16, sfn_e=2

I think according to schedulinglist, I should get SIB3 here.

also, I get SIB2 and 8 when the log shows:

trying to decode other sibs, subframe=0, sf_idx=0, sfn=1636, si_periodicity=32, sfn_e=4

but I think I should get SIB5 here.

Cell search information and MIB decoding information is shown below:

Opening RF device with 1 RX antennas...
Opening USRP channels=1, args: type=b200,master_clock_rate=23.04e6
Starting AGC thread...
Tunning receiver to 2120.000 MHz
Searching for cell...
*Found Cell_id: 366 FDD, CP: Normal  , DetectRatio=100% PSR=8.33, Power=27.9 dBm
 Found Cell_id:   0 FDD, CP: Normal  , DetectRatio= 0% PSR=0.00, Power=-inf dBm
 Found Cell_id:   0 FDD, CP: Normal  , DetectRatio= 0% PSR=0.00, Power=-inf dBm
Decoding PBCH for cell 366 (N_id_2=0)
Setting sampling rate 23.04 MHz
Finding PSS... Peak:      1.2, FrameCnt: 0, State: 0
Finding PSS... Peak:      1.2, FrameCnt: 0, State: 0
Finding PSS... Peak:      6.9, FrameCnt: 0, State: 1
 - Type:            FDD
 - PCI:             366
 - Nof ports:       2
 - CP:              Normal
 - PRB:             100
 - PHICH Length:    Normal
 - PHICH Resources: 1
 - SFN:             472
Decoded MIB. SFN: 472, offset: 2

So my question is here: Why I get some SIB at a wrong place?


Thank you for your help

Best Regards,

Harley Lin





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