[srslte-users] SRS support
ALEJANDRO BLANCO PIZARRO
100283180 at alumnos.uc3m.es
Fri May 24 14:44:13 UTC 2019
If I remeber correctly. Cell specific IS whithin the sib2 configuration and
ue in the rrc message, both should be unabled.
Best,
Alejandro
El vie., 24 may. 2019 16:20, Naveen Rawat <
naveen.rawat at cohere-technologies.com> escribió:
> Yes.. I did see the difference.. but I made changes appropriately. Did
> you enable ue specific srs or cell specific??
>
> Get Outlook for Android <https://aka.ms/ghei36>
>
> ------------------------------
> *From:* ALEJANDRO BLANCO PIZARRO <100283180 at alumnos.uc3m.es>
> *Sent:* Friday, May 24, 2019 7:18:32 AM
> *To:* Naveen Rawat; srslte-users
> *Subject:* Re: [srslte-users] SRS support
>
> Hi Naveen,
>
> I do not remember such error when I did it. BTW, the version that I used
> of srsLTE was 17.10 I think.
>
> Best,
> Alejandro
>
> El vie., 24 may. 2019 16:11, Naveen Rawat <
> naveen.rawat at cohere-technologies.com> escribió:
>
>> Hi Alejandro,
>>
>>
>>
>> After enabling SIB, I see that ping is not going through over LTE link
>> between UE and eNB. Did you face this issue as well?
>>
>>
>>
>> Thanks and Regards
>>
>> Naveen Rawat
>>
>>
>>
>> *From: *ALEJANDRO BLANCO PIZARRO <100283180 at alumnos.uc3m.es>
>> *Date: *Thursday, May 23, 2019 at 2:51 AM
>> *To: *Naveen Rawat <naveen.rawat at cohere-technologies.com>
>> *Subject: *Re: [srslte-users] SRS support
>>
>>
>>
>> Hi Naveen,
>>
>>
>>
>> Thanks for response and this is good to know. Can you tell me to what
>> extent were you able to make it work. I am worried that after SRS is sent
>> by UE, since eNB cannot understand it, this could make the connection
>> un-stable.
>>
>>
>>
>> Thanks for response and this is good to know. Can you tell me to what
>> extent were you able to make it work. I am worried that after SRS is sent
>> by UE, since eNB cannot understand it, this could make the connection
>> un-stable.
>>
>>
>>
>> I do not completely understand it. Basically, the srsenb cannot handle
>> the SRS, but this does not mean that the communication becomes unstable.
>> What is going to happen, depending in your SRS configuration, you will have
>> in a specific subframe and position the SRS and the srsenb is not going to
>> anything with that information. In my case, I saved the SRS in a file to
>> later process it offline. I was interesting in estimating the distance
>> between the UE and eNB but not in real time, so it is does not mind.
>>
>>
>>
>> Please help me with following questions:
>>
>> 1. Location of your modifications.
>>
>> What I am going to show you was personal decisions of the code, probably
>> there is a better way to do it.
>>
>>
>>
>> 1º Add to the sib.conf (attached) the configuration regarding the SRS
>> configuration:
>>
>>
>>
>> srs_ul_cnfg =
>> {
>> bw_cnfg = 0; // LIBLTE_RRC_SRS_BW_CONFIG_ENUM
>> subfr_cnfg = 1; // LIBLTE_RRC_SRS_SUBFR_CONFIG_ENUM
>> ack_nack_simul_tx = false; // bool
>> max_up_pts = true; // bool
>> max_up_pts_present = true; // bool
>> present = true; // bool
>> };
>>
>>
>>
>> 2º Add the lines to take the information from sib.conf in the parser:
>> enb_cfg_parser (attached)
>>
>>
>>
>> // SRS_UL_CNFG configuration
>> parser::section srs_ul_cnfg("srs_ul_cnfg");
>> rr_config.add_subsection(&srs_ul_cnfg);
>>
>> srs_ul_cnfg.add_field(
>> new parser::field_enum_num<LIBLTE_RRC_SRS_BW_CONFIG_ENUM,uint8>
>> ("bw_cnfg", &data->rr_config_common_sib.srs_ul_cnfg.bw_cnfg,
>> liblte_rrc_srs_bw_config_num,LIBLTE_RRC_SRS_BW_CONFIG_N_ITEMS)
>> );
>> srs_ul_cnfg.add_field(
>> new parser::field_enum_num<LIBLTE_RRC_SRS_SUBFR_CONFIG_ENUM,uint8>
>> ("subfr_cnfg", &data->rr_config_common_sib.srs_ul_cnfg.subfr_cnfg,
>> liblte_rrc_srs_subfr_config_num,LIBLTE_RRC_SRS_SUBFR_CONFIG_N_ITEMS)
>> );
>>
>> srs_ul_cnfg.add_field(
>> new parser::field<bool>
>> ("ack_nack_simul_tx",
>> &data->rr_config_common_sib.srs_ul_cnfg.ack_nack_simul_tx)
>> );
>> srs_ul_cnfg.add_field(
>> new parser::field<bool>
>> ("max_up_pts", &data->rr_config_common_sib.srs_ul_cnfg.max_up_pts)
>> );
>> srs_ul_cnfg.add_field(
>> new parser::field<bool>
>> ("max_up_pts_present",
>> &data->rr_config_common_sib.srs_ul_cnfg.max_up_pts_present)
>> );
>> srs_ul_cnfg.add_field(
>> new parser::field<bool>
>> ("present", &data->rr_config_common_sib.srs_ul_cnfg.present)
>> );
>>
>>
>>
>> And change from false to true this line:
>> sib2->rr_config_common_sib.srs_ul_cnfg.present = true;
>>
>>
>>
>> 3º Add to srsenb/src/upper/rrc.cc these lines of code:
>>
>>
>>
>> // Configure Sounging Reference Signal
>> if (parent->sib2.rr_config_common_sib.srs_ul_cnfg.present){
>> fprintf(stderr, "Estamos configurnado srs\n");
>> phy_cfg->srs_ul_cnfg_ded_present = 1;
>> phy_cfg->srs_ul_cnfg_ded.srs_bandwidth = LIBLTE_RRC_SRS_BANDWIDTH_BW0;
>> phy_cfg->srs_ul_cnfg_ded.srs_hopping_bandwidth =
>> LIBLTE_RRC_SRS_HOPPING_BANDWIDTH_HBW0 ;
>> phy_cfg->srs_ul_cnfg_ded.cyclic_shift = LIBLTE_RRC_CYCLIC_SHIFT_CS0 ;
>> phy_cfg->srs_ul_cnfg_ded.freq_domain_pos = 0;
>> phy_cfg->srs_ul_cnfg_ded.srs_cnfg_idx = 0;
>> phy_cfg->srs_ul_cnfg_ded.tx_comb = 0;
>> phy_cfg->srs_ul_cnfg_ded.setup_present = 1;
>> phy_cfg->srs_ul_cnfg_ded.duration = 1;
>> }
>>
>>
>>
>> Now, the configuration from SIB2 and rrc messages supports SRS. As the UE
>> decodes this informatio, it will send the SRS to the eNB without any
>> configuration from the UE side.
>>
>>
>>
>> 4º Now you have to take the SRS from the eNB. What I did was to configure
>> the SRS to be sent every 10 TTI, so I save the SRS to a file. Assuming that
>> it is sent the last symbol of the subframe you can extract it. To do it,
>> you can take it from the file phch_worker.cc, the variable where you can
>> take it is the buffer of the eNB.
>>
>> Here an example to do it:
>>
>>
>>
>> srslte_filesink_t sink;
>>
>> int start = X % where the signal start
>>
>> int size = 576*2; % the size of the SRS
>> srslte_filesink_init(&sink, buf, SRSLTE_COMPLEX_FLOAT_BIN);
>> cf_t * signal = enb_ul.fft.out_buffer;
>> srslte_filesink_write(&sink, (void *) &signal[start] , tot);
>>
>>
>>
>> Sorry but this part is not programatical, it depends on your
>> configuration. But was enough for my purpose.
>>
>>
>>
>>
>>
>> 1. With srsUE, you said SRS could be enabled, but srsEnb could not
>> understand them. Did connection drop or did not even work?
>>
>>
>> 1. If srsENB somehow worked, did you make changes to ignore SRS
>> received ?
>>
>> The connection does not drop. And not
>>
>>
>> 1.
>>
>>
>> 1. Did you make progress with smartphone for SRS ?
>>
>>
>>
>> Unfortunately not. Sorry
>>
>>
>>
>> If you achieve to work with a smartphone tell me.
>>
>>
>>
>> I totally recommend you to read the standard and forums to understadn how
>> to configure the SRS.
>>
>>
>>
>> Good luck. Best,
>>
>> Alejandro
>>
>>
>>
>> I am trying to achieve something similar to what you did, by using SRS at
>> eNB for my experimentations.
>>
>>
>>
>> Thanks and Regards
>>
>> Naveen Rawat
>>
>>
>>
>>
>>
>> *From: *ALEJANDRO BLANCO PIZARRO <100283180 at alumnos.uc3m.es>
>> *Date: *Wednesday, May 22, 2019 at 1:56 AM
>> *To: *Naveen Rawat <naveen.rawat at cohere-technologies.com>
>> *Cc: *"srslte-users at lists.softwareradiosystems.com" <
>> srslte-users at lists.softwareradiosystems.com>
>> *Subject: *Re: [srslte-users] SRS support
>>
>>
>>
>> Hi Naveen,
>>
>>
>>
>> From my experience, SRS is not fully handled by srsLTE. As far as I know,
>> srsUE is able to send it but srsenb cannot use it.
>>
>>
>>
>> One year ago, I worked with SRS and basically what I did was to add some
>> parameter to SIB2 and RRC messages to active them, thus the srsUE can send
>> it. As the srsenb cannot handle it, I saved the SRS in a file and process
>> it offline.
>>
>>
>>
>> In addition, I tried to configure the SRS and check if a smartphone can
>> send it, but I couldn't do it. I used the srsUE for my application.
>>
>>
>>
>> Here you have the message that I posted in the mailing list of srsLTE:
>> http://www.softwareradiosystems.com/pipermail/srslte-users/2018-May/001575.html.
>> Thanks to Ismael I could use the SRS.
>>
>>
>>
>> If you need further information tell me. I can tell you what was my
>> configuration and which files of the code I modified.
>>
>>
>>
>> Best,
>>
>> Alejandro
>>
>>
>>
>> El mar., 21 may. 2019 a las 9:10, Naveen Rawat (<
>> naveen.rawat at cohere-technologies.com>) escribió:
>>
>> Hi srsLte Team,
>>
>>
>>
>> I am looking for setting for enabling SRS. I found a bug was opened for
>> this but looks like bug was closed with a commit. However I am unable to
>> find the related config. Can you please tell if this was implemented from
>> eNB side and what is the config to trigger that.
>>
>>
>>
>> Thanks and Regards
>>
>> Naveen Rawat
>>
>> _______________________________________________
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>>
>>
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