Re: [Discuss-gnuradio] Managing Tags in Multiple Streams

[Ramazan Çetin]

Hello again,

We have also tried "add block" for combining two tagged streams. 
However, add block ignores packet boundaries. This causes "tP" error on 
USRP side due to sending another tagged packet before finishing previous 
one. In attached figure, this situation can be observed.

We just need to send packets to USRP device from two different TAP 
interfaces. We need a block like FIFO. The packet that comes first from 
one of the inputs should be sent first. After finishing this, another 
packet should be sent.

Is there any solution for this problem?


On 5.07.2019 17:07, Ramazan Çetin wrote:
> Hello all,
>
> We want to transmit two channels OFDM signal. Each channel has 500kHz 
> bandwidth.
>
> We want to connect each channel to  TAP interfaces. At the end, we 
> have two OFDM receivers and two OFDM transmitters. We are getting 
> trouble with putting tags these two streams (from TAP0 and TAP1). The 
> messages that comes from TAP0 and TAP1 interfaces are different sized. 
> We have combined these two OFDM TX paths using "Tagged Stream Mux". 
> The disadvantage of this block is that it waits length tag from both 
> of the inputs, so we can send data when both of the interfaces are 
> active. But we should also send when one of the channels is active.
>
> The GNU Radio FG is attached. So, how can we send multiple tagged 
> streams to USRP device? Does using Tagged Stream Mux is true approach 
> for this task?
>
> You may suggest another approach.
>
> Best regards.
>
> Ramazan

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