[srslte-users] Can't receive data in subframe 0

Tue Apr 11 16:39:28 UTC 2017

Yes you are free to mix RA types as long as there is no collision.

On Tue, 11 Apr 2017 at 18:37 Kewin Rausch <krausch at fbk.eu> wrote:

> Hi all,
>
> I had a quick discussion with Felipe, and it seems that part of the
> problem was a little miss-comprehension on how the Physical channels were
> used.
>
> Until now I've always been able to allocate a DCI message on the PCCH data
> on the PDLSCH (with 6 RBs and 3 CFI); at PHY layer, if I'm not wrong, the
> PCCH act as an indexing channel. Basically it provides the necessary
> information to read the actual data, but you should not write MAC/RRC
> control data on the PCCH, since it is multiplexed in the PDLSCH. Can be
> pictured as the "index for a page made of paragraphs".
>
> At high values of the CFI, potentially one can have a higher granularity
> in the allocation of single RB or RB groups, while with reduced CFI
> values(1), you have less DCI slots and so less granularity on how to
> organize your sub-frame data.
>
> There is an additional question I have for srsLTE gurus or everyone else
> here:
> usually I select a Resource Allocation(RA) strategy (type 0, 1 or 2) to
> create the DCI message, but once I pick one RA type, am I restricted to
> keep using that in the sub-frame?
> Technically, If I introduce a way to avoid RB allocation collision (a DCI
> cannot reserve RB of another DCI), I don't see anything which restrict me
> to do so... any comment about this?
>
> Cheers,
> Kewin R.
>
> On Tue, Apr 11, 2017 at 6:11 PM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
> Hi all, I think Felipe might be right and there might be some combination
> of CFI and DCI allocation that is undetected by the pdcch_ue_locations
> function. I rewrote some bits of that function to make it more clear and
> readable and added the suggestion from Felipe.
>
> would be great if you could try it. I just pushed it on next.
>
> Thanks for catching that
>
> On Tue, 11 Apr 2017 at 14:20 Kewin Rausch <krausch at fbk.eu> wrote:
>
> Hi everyone,
>
> I'm currently able to transmit data on subframe 0 without having to modify
> the srsLTE library code.
> I've already tested such data transmission with srsUE and legacy hardware
> like Nexus 5, and it works nicely (data transmitted on subframe 0, in my
> case, is the SIB2).
>
> My CFI is 3, and I use 6 RB (1.4 MHz) LTE signal.
>
> Cheers,
> Kewin R.
>
>
> On Tue, Apr 11, 2017 at 1:57 PM, Felipe Augusto Pereira de Figueiredo <
> zz4fap at gmail.com> wrote:
>
> Hi Folks,
>
> I ran some tests and figured out DCI was not being found during the DCI
> search.
> Then, I went to function "srslte_pdcch_ue_locations_ncce" in pdcch.c and
> changed the following line. The "for" should follow the values in Table
> 9.1.1-1: PDCCH candidates monitored by a UE in TS 36.213.
>
>     //for (i = 0; i < SRSLTE_MIN(nof_cce / L,
> S[l]/PDCCH_FORMAT_NOF_CCE(l)); i++) {
>     for (i = 0; i < (S[l]/PDCCH_FORMAT_NOF_CCE(l)); i++) {
>
> Now I'm able to find the CRC corresponding to the C-RNTI being used,
> however, I still can't decode the transmitted data.
>
> Kind Regards,
>
> Felipe Augusto
>
> On Tue, Apr 11, 2017 at 10:18 AM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
> sharetechnote.com is a good reference.
>
> On Mon, 10 Apr 2017 at 16:18 Felipe Augusto Pereira de Figueiredo <
> zz4fap at gmail.com> wrote:
>
> Dear folks,
>
> Could you kindly provide me with some references on how to calculate if
> there is enough space for the DCI and the PDSCH for a given CFI
> configuration?
> As told before, I'm trying to transmit data on subframe 0 but it has been
> no avail so far.
>
> I'm using CFI equal to 1 instead of 3 (but I also tried with CFI=3),
> sending just one DCI (I'm using the pdsch_enodeb example) and the data is
> using all the RBs (25 RBs) with MCS=0 which corresponds to a TB of 680 bits.
>
> I'd like to calculate it and try to understand what is happening.
>
> Many thanks and Best regards,
>
> Felipe Augusto
>
>
>
> On Mon, Apr 3, 2017 at 10:50 PM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
> I don't know. You should calculate it. It depends on the BW.
>
> On Mon, 3 Apr 2017 at 22:49 Felipe Augusto Pereira de Figueiredo <
> zz4fap at gmail.com> wrote:
>
> Dear Ismael,
>
> Many thanks for your reply!
>
> I'm using CFI equal to 1 instead of 3 (but I also tried with CFI=3),
> sending just one DCI (I'm using the pdsch_enodeb example) and the data is
> using all the RBs (25 RBs) with MCS=0 which corresponds to a TB of 680 bits.
>
> Do you think I have enough space for the DCI with that configuration?
>
> Thanks and Kind Regards,
>
> Felipe Augusto
>
>
>
> On Mon, Apr 3, 2017 at 10:41 PM, Ismael Gomez <
> ismael.gomez at softwareradiosystems.com> wrote:
>
> Hi Felipe,
>
> There are less resource elements in subframe 0 for PDSCH. Make sure that
> there is enough space for the DCI and the PDSCH for your CFI configuration.
>
> On Sun, 2 Apr 2017 at 11:16 Felipe Augusto Pereira de Figueiredo <
> zz4fap at gmail.com> wrote:
>
> Hi Folks,
>
> I'm doing some experiments with the srsLTE source code and I'd like to
> transmit data on every subframe 0, however, even after modifying the source
> code (the pdsch enodeb and ue examples) I'm not receiving anything on any
> subframe 0 except PBCH transmissions (MIB). I added some printf's and
> figured out that no DCI is being found during the blind search at ue side.
>
> I'm not sure if the problem is that the enodeb is not adding the DCI
> properly or if the ue is not being able to decode DCI on subframe 0.
>
> Is there any bug/tricky that refrains the eNodeB or the UE from
> transmitting/receiving data on subframe 0?
>
> I'm using pdsch_enodeb and pdsch_ue examples.
>
> Many thanks in advance and Kind Regards,
>
> Felipe Augusto
>
>
>
> ---------- Forwarded message ----------
> From: *Felipe Augusto Pereira de Figueiredo* <zz4fap at gmail.com>
> Date: Fri, Mar 31, 2017 at 5:17 PM
> Subject: Can't receive data in subframe 0
> To: srslte-users at lists.softwareradiosystems.com
>
>
> Hi srsLTE group,
>
> I'm doing some experiments with the code and I'd like to transmit data on
> subframe 0, however, even after modifying the source code I'm not receiving
> anything on any subframe 0 except PBCH transmissions (MIB). I figured out
> that any DCI is being found during the blind search but as I understand, at
> eNodeB side it is being added to the grid.
>
> Is there any bug/tricky that refrains the eNodeB or the UE from
> transmitting/receiving data on subframe 0?
>
> I'm using pdsch_enodeb and pdsch_ue examples.
>
> Thanks and Kind Regards,
>
> Felipe Augusto
>
>
>
>
>
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