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