Hello All, > > I have a question about the implementation of the mapping from an incoming > bit-stream to generate an output of frequency-domain OFDM symbols > (ofdm_mapper_bcv_impl.cc). > > Let's say that the incoming bit-stream is '0x00', '0x36', '0x00', '0x36', > '0xff', '0x3f', '0x37', '0x27' '0x37'. Converting this from a hex to binary > representation, this stream is: > > 0000 0000 0011 0110 0000 0000 0011 0110 1111 1111 0011 1111 0011 0111 0010 > 0111 0011 0111. > > Assuming that we use QAM64, this stream should be broken up into chunks of > 6 bits each, to give us: > > 000000 000011 011000 000000 001101 101111 111100 111111 001101 110010 > 011100 110111. > > Once the mapping is done, this should correspond to (at least, in my head) > the frequency-domain representation of the 6-bit chunks (shown in Hex > below): > > 0 3 28 0 0d 2f 3c 3f 0d 32 1c 37. > > But the output from the stock implementation (ofdm_mapper_bcv_impl.cc) is: > > 1 18 3 0 36 3c 3f f 37 1c 32 d. > > I know my question has to do with endianness: Is the reference > implementation correct? If so, how does one interpret the endianness of the > incoming bit-stream? > > Thanks! > > Best, > Aditya >
Upon further examination, this does seem like classic little-endianness.
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