Hi Adhitha, The tx_stage6.grc outputs BPSK packets. If you want to use OFDM, the OFDM examples are good references. To detect OFDM packets, use schmidl & cox OFDM sync module. Anyway, I'm glad that you've got your system going.
Regards, Edwin Adhitha Dias <adhithadia...@gmail.com>于2017年8月10日周四 上午10:18写道： > Hi Edwin, > > I used OFDM examples and now I can transmit and receive packets. I am > sorry about mentioning the name as Derek, Derek helped me earlier to set up > the USRPs from UHD USRP mailing list. > Your information was very helpful. Thank a lot for your help. > > Best regards, > Adhitha Dias > > On Thu, Aug 10, 2017 at 12:36 PM, Adhitha Dias <adhithadia...@gmail.com> > wrote: > >> Hi Edwin, >> >> tx_stage6.grc outputs a packet that is not modulated, right? The >> communication should be based on WiFi 802.11. When I insert an OFDM Mod OOT >> at the end of tx_stage.grc with the USRP sink, the USRP does not give an >> output. I used /src/gnuradio/gr-digital/examples/packet/ofdm/tx_ofdm.grc >> with the USRP, then it transmits the OFDM modulated packets but I am >> uncertain how to detect the packet at the receiving end once it is >> modulated with OFDM. The example rx_ofdm does not correlate the incoming >> packet so as to detect the preamble and it does not yield any output when >> used with another USRP at the receiving end. >> >> Furthermore, there is an OOT OFDM Insert Preamble but there is no example >> on how to use it. Please help me if can figure out a way to detect the >> preamble for OFDM WiFi based communication 802.11 >> >> Thank you! >> Regards, >> Adhitha >> >> On Thu, Aug 10, 2017 at 12:27 PM, Adhitha Dias <adhithadia...@gmail.com> >> wrote: >> >>> Hi Derek, >>> >>> tx_stage6.grc outputs a packet that is not modulated, right? The >>> communication should be based on WiFi 802.11. When I insert an OFDM Mod OOT >>> at the end of tx_stage.grc with the USRP sink, the USRP does not give an >>> output. I used /src/gnuradio/gr-digital/examples/packet/ofdm/tx_ofdm.grc >>> with the USRP, then it transmits the OFDM modulated packets but I am >>> uncertain how to detect the packet at the receiving end once it is >>> modulated with OFDM. The example rx_ofdm does not correlate the incoming >>> packet so as to detect the preamble and it does not yield any output when >>> used with another USRP at the receiving end. >>> >>> Furthermore, there is an OOT OFDM Insert Preamble but there is no >>> example on how to use it. Please help me if can figure out a way to detect >>> the preamble for OFDM WiFi based communication 802.11 >>> >>> Thank you! >>> Regards, >>> Adhitha Dias >>> >>> On Thu, Aug 10, 2017 at 12:28 AM, 李博远 <lbyhp...@gmail.com> wrote: >>> >>>> Hi Adhitha, >>>> >>>> If you check out the tx_stage6.grc example in the folder >>>> /src/gnuradio/gr-digital/example/packet/, you can see a Protocol Formatter. >>>> It generates a header which contains a preamble and some additional >>>> information, and pumps it out through the header output port. The other >>>> output port, called payload, outputs the original information from the >>>> signal source. And there is another module called Tagged Stream Mux. It >>>> combines the header and the payload, producing a packet. >>>> >>>> As for the receiver, check out the packet_rx.grc. The Correlation >>>> Estimation correlates the received signal with the modulated preamble and >>>> finds out the beginning of each packet. The Header/Payload Demux splits the >>>> header from the payload. >>>> >>>> Hope this answers your question. >>>> >>>> Regards, >>>> Edwin >>>> >>>> Adhitha Dias <adhithadia...@gmail.com>于2017年8月9日周三 上午5:34写道： >>>> >>>>> Hi Edwin, >>>>> >>>>> I tried the examples but there is no information on how to detect the >>>>> preamble. What I need to do is, once the Short Training Field is >>>>> identified >>>>> record the packet so that I can use the Long Training Field can be used >>>>> for >>>>> processing. >>>>> >>>>> I've been looking in to the examples for a couple of days but I still >>>>> don't have an idea on how the preamble is inserted and how to detect the >>>>> Short Training Field in order to record the un-modulated, raw, time domain >>>>> received signal. >>>>> >>>>> I really appreciate if you can kindly provide some information on this. >>>>> >>>>> Thanks a lot! >>>>> Regards, >>>>> Adhitha Dias >>>>> >>>>> On 9 Aug 2017 00:12, "李博远" <lbyhp...@gmail.com> wrote: >>>>> >>>>>> Hi Adhitha, >>>>>> >>>>>> Just check out the examples in the folder >>>>>> /src/gnuradio/gr-digital/examples/packet/ >>>>>> >>>>>> Regards, >>>>>> Edwin >>>>>> >>>>> >>> >> >
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