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diff --git a/Transceiver52M/README b/Transceiver52M/README new file mode 100644 index 0000000..491693c --- /dev/null +++ b/Transceiver52M/README @@ -0,0 +1,35 @@ +The Transceiver + +The transceiver consists of three modules: + --- transceiver + --- radioInterface + --- USRPDevice + +The USRPDevice module is basically a driver that reads/writes +packets to a USRP with two RFX900 daughterboards, board +A is the Tx chain and board B is the Rx chain. + +The radioInterface module is basically an interface b/w the +transceiver and the USRP. It operates the basestation clock +based upon the sample count of received USRP samples. Packets +from the USRP are queued and segmented into GSM bursts that are +passed up to the transceiver; bursts from the transceiver are +passed down to the USRP. + +The transceiver basically operates "layer 0" of the GSM stack, +performing the modulation, detection, and demodulation of GSM +bursts. It communicates with the GSM stack via three UDP sockets, +one socket for data, one for control messages, and one socket to +pass clocking information. The transceiver contains a priority +queue to sort to-be-transmitted bursts, and a filler table to fill +in timeslots that do not have bursts in the priority queue. The +transceiver tries to stay ahead of the basestation clock, adapting +its latency when underruns are reported by the radioInterface/USRP. +Received bursts (from the radioInterface) pass through a simple +energy detector, a RACH or midamble correlator, and a DFE-based demodulator. + +NOTE: There's a SWLOOPBACK #define statement, where the USRP is replaced +with a memory buffer. In this mode, data written to the USRP is actually stored +in a buffer, and read commands to the USRP simply pull data from this buffer. +This was very useful in early testing, and still may be useful in testing basic +Transceiver and radioInterface functionality. |