[Discuss-gnuradio] Questions on stream tags

[Hoang Ngo Khac]

Dear List,

I'm new to stream tags. Could someone help me to understand about stream tags and know how to use it?

1. In GNU Radio Manual: "A stream tags is generated by a block's work function and from there on flows the downstream...until it reaches a sink...".

If we use tags to tell the USRP Sink to start/stop the TX chain, do we need to modify the USRP Sink block?

I found that gr_uhd_usrp_sink.cc file contains the get_tags_in_range() function. However, this file is not, at first, in the GNU Radio 3.7.0 source folder. How to add this to project and make it work with USRP Sink?

2. I am implementing a model of ofdm-based two-way relaying network apply network coding. Up to now, each single transmission in one time slot are done, but the model runs without any timing synchronization. For this, I need to use TDMA, and stream tags is the solution. I list here the steps to make TDMA with stream tags. Could you leave some comments if I miss some thing?

+ Add tags to stream; using provided block such as PDU to Tagged Stream, or custom block.

+ Write a block for error checking, repeat request...

Sorry if my questions are silly.

Thanks,

Hoang

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Hoang Ngo-Khac

Vietnam National University, Hanoi (VNU-H)

Univ. of Engineering and Technology (UET)

Faculty of Electronics and Telecommunications (FET)

Alternative email:  address@hidden

Mobilephone:  +84.163.682.7874