I am currently working on the implementation of OpenLTE for the USRP N210.
I have successfully integrated an SRC on the receive and send function and I am able to send/receive data to/from the USRP without any crash.
The sample rate of the USRP is 6.25Mhz and I am operating OpenLTE at a bandwith of 5Mhz.
The SRC is implemented with a factor of 768/625 on receiving and 625/768 on sending on both the send/receive function (just before calling the phy->radio_interface function). The run of the SRC add an overload of 0.3ms. The radio_interface of the PHY is still called each 1ms.
In PHY I have keep "fs = LIBLTE_PHY_FS_15_36MHZ" in the hope that all the calculation will remain the same. Unfortunatly It don't seem that the process_dl function (in PHY) is sending the right data in tx_buff when calling the radio->send(tx_buff) function. I have tested if the SRC was corrumpting the data but It is not the case.
For the moment I only want to make the eNodeB to advertise itself. To make sure that the problem wasn't the USRP N210, I have run OpenLTE with an USRP B210 while recording the sent data with the USRP N210 with a sample rate of 6.25MS/s. Then when I have replayed the captured data with the USRP N210 I was actually seeing the advertising of the eNodeB on the UE.
In RADIO I have :
N_samps_per_subfr = LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZ
N_rx_samps = 1250
N_tx_samps = 1250
In LIBLTE_PHY :
// 5MHz bandwidth with usrp2 #define LIBLTE_PHY_N_SAMPS_PER_SLOT_6_25MHZ 3125 #define LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZ (LIBLTE_PHY_N_SAMPS_PER_SLOT_6_25MHZLIBLTE_PHY_N_SLOTS_PER_SUBFR)
_#define LIBLTE_PHY_N_SAMPS_PER_FRAME_6_25MHZ (LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZLIBLTE_PHY_N_SUBFR_PER_FRAME)
Do you have any ideas concerning why the data passed in the radio->send(tx_buff) are not the same when using the USRP N210 ? Or any remark about my implementation of the USRP N210 ?
Last edit: Jerome Peyroutat 2016-08-17
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Hi,
I am currently working on the implementation of OpenLTE for the USRP N210.
I have successfully integrated an SRC on the receive and send function and I am able to send/receive data to/from the USRP without any crash.
The sample rate of the USRP is 6.25Mhz and I am operating OpenLTE at a bandwith of 5Mhz.
The SRC is implemented with a factor of 768/625 on receiving and 625/768 on sending on both the send/receive function (just before calling the phy->radio_interface function). The run of the SRC add an overload of 0.3ms. The radio_interface of the PHY is still called each 1ms.
USRP--(6.25MS/s)-->RADIO_receive--(resample 768/625)-->PHY_radio_interface--(...)-->RADIO_send--(resample 625/768)-->USRP
In PHY I have keep "fs = LIBLTE_PHY_FS_15_36MHZ" in the hope that all the calculation will remain the same. Unfortunatly It don't seem that the process_dl function (in PHY) is sending the right data in tx_buff when calling the radio->send(tx_buff) function. I have tested if the SRC was corrumpting the data but It is not the case.
For the moment I only want to make the eNodeB to advertise itself. To make sure that the problem wasn't the USRP N210, I have run OpenLTE with an USRP B210 while recording the sent data with the USRP N210 with a sample rate of 6.25MS/s. Then when I have replayed the captured data with the USRP N210 I was actually seeing the advertising of the eNodeB on the UE.
In RADIO I have :
N_samps_per_subfr = LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZ
N_rx_samps = 1250
N_tx_samps = 1250
In LIBLTE_PHY :
// 5MHz bandwidth with usrp2
#define LIBLTE_PHY_N_SAMPS_PER_SLOT_6_25MHZ 3125
#define LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZ (LIBLTE_PHY_N_SAMPS_PER_SLOT_6_25MHZLIBLTE_PHY_N_SLOTS_PER_SUBFR)
_#define LIBLTE_PHY_N_SAMPS_PER_FRAME_6_25MHZ (LIBLTE_PHY_N_SAMPS_PER_SUBFR_6_25MHZLIBLTE_PHY_N_SUBFR_PER_FRAME)
Do you have any ideas concerning why the data passed in the radio->send(tx_buff) are not the same when using the USRP N210 ? Or any remark about my implementation of the USRP N210 ?
Last edit: Jerome Peyroutat 2016-08-17
Hi Jerome,'
How is the issue, did you resovle it?
Thanks
Usrp n210 its not on the list available for openlte. B2XX is the proper
radio to use.
On Fri, Sep 14, 2018, 8:12 PM eugene ehan@users.sourceforge.net wrote:
Hi Kita Andi,
It looks that Jerome added a SRC for N210, but no sure if it works.
Thanks