Hello everyone,
I've been trying to implement a switching mechanism between 2 transmitters. I use gr-ieee802-11 and there will be 2 messages with different MAC addresses for each transmitter. At a given time, only one of the transmitters will be transmitting its corresponding 802.11 frames and other transmitter can stop or send anything except 802.11 frames. They will transmit their frames in a turn. I have an X300 with CBX daughter boards and I m planning to use each daughter board as transmitter. For this purpose, I created 2 messages and each message is sent through 'Selector' block which has 2 inputs and 1 output. Selector block switches between the frames and a dummy message(vector source) according to the input index which is set by a signal source. Ultimately, only one of the transmitters will be transmitting the frames while the other is sending a dummy message.
I created the following flowgraph (
https://imgur.com/a/SwFGS ). When I run the flowgraph, I got these errors after the first switch between the messages:
FATAL: Missing a required length tag on port 0 at item #0
thread[thread-per-block[33]: <block ofdm_cyclic_prefixer (14)>]: Missing length tag.
thread[thread-per-block[37]:
<block gr uhd usrp sink (26)>]: RuntimeError: On node
0/DmaFIFO_0, input port 0 is already connected.
I don't know what I m doing wrong and I m not sure if this is a good way for the transmitter switching described above. I will appreciate if you give your suggestions for this.