Hi all,
We are currently doing a project, which aims to look for white space over a chosen frequency range, automatically select the best channel (considering a 1 Mhz span with 5 channels, each of 200kHz). The transmitter would tune to the centre frequency of this best channel, and the receiver should be able to detect this transmission from the 1Mhz range, and perform a handshake with the transmitter so the transmitter knows the receiver has identified the chosen frequency. The transmitter should then transmit the information (i.e a text file). For the sending a text file part, we have been able to do this using QPSK and GMSK with partial success (however the text file is missing information at the end), the main part we have not been able to resolve is how the USRP receiver could detect the chosen frequency, and then let the transmitter know it has identified this. Can anyone suggest some ways in which this can be done, I have broken it into a few stages: 1) How to get the transmitter to continuously transmit at the specific frequency (i.e either 710.1, 710.3, 710.5, 710.7, 710.9 (Mhz) - what should be transmitted, e.g. a type of continuous code that could be identified by the receiver? 2) What is a good way to get the receiver to scan the 5 frequencies, and at each frequency, how could it identify that this is a transmission from the correct device, i.e using an access code, or a tag of some sort?, if it does not identify this as the required transmission then it will move on to the next frequency. 3) Once the receiver has detected the correct frequency, how can it inform the transmitter that it has identified this frequency is to be used and tell it to start transmitting the real information (the text file). I know this is probably a lot to ask, but any help on any part of it, or some ideas that we can start to look at would be appreciated. Thanks, Neil. ________________________________ From: Discuss-gnuradio <discuss-gnuradio-bounces+ndshelley=hotmail.co...@gnu.org> on behalf of discuss-gnuradio-requ...@gnu.org <discuss-gnuradio-requ...@gnu.org> Sent: 20 July 2017 19:33 To: ndshel...@hotmail.co.uk Subject: Welcome to the "Discuss-gnuradio" mailing list Welcome to the Discuss-gnuradio@gnu.org mailing list! To post to this list, send your message to: discuss-gnuradio@gnu.org General information about the mailing list is at: https://lists.gnu.org/mailman/listinfo/discuss-gnuradio Discuss-gnuradio -- GNU Radio, a free software radio toolkit<https://lists.gnu.org/mailman/listinfo/discuss-gnuradio> lists.gnu.org To see the collection of prior postings to the list, visit the Discuss-gnuradio Archives. Using Discuss-gnuradio: To post a message to all the list ... If you ever want to unsubscribe or change your options (eg, switch to or from digest mode, change your password, etc.), visit your subscription page at: https://lists.gnu.org/mailman/options/discuss-gnuradio/ndshelley%40hotmail.co.uk You can also make such adjustments via email by sending a message to: discuss-gnuradio-requ...@gnu.org with the word `help' in the subject or body (don't include the quotes), and you will get back a message with instructions. You must know your password to change your options (including changing the password, itself) or to unsubscribe without confirmation. It is: !HpXlm9k6u5! Normally, Mailman will remind you of your gnu.org mailing list passwords once every month, although you can disable this if you prefer. This reminder will also include instructions on how to unsubscribe or change your account options. There is also a button on your options page that will email your current password to you.
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