Changes between Version 7 and Version 8 of OFDM/MIMO/Docs/PHYDetails/FrameFormat


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Timestamp:
Aug 29, 2009, 9:16:11 PM (15 years ago)
Author:
murphpo
Comment:

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  • OFDM/MIMO/Docs/PHYDetails/FrameFormat

    v7 v8  
    77
    88[[Image(OFDM/MIMO/Docs/Images:FrameFormatOverview.png)]]
     9
     10The actual format depends on the antenna mode:
     11
     12'''SISO Frame Format'''[[BR]]
     13[[Image(OFDM/MIMO/Docs/Images:SISO_Frame_Format.png, 684)]]
     14
     15'''Alamouti Frame Format'''[[BR]]
     16[[Image(OFDM/MIMO/Docs/Images:SISO_Frame_Format.png, 684)]]
     17
     18'''Multiplexing Frame Format'''[[BR]]
     19[[Image(OFDM/MIMO/Docs/Images:MIMO_Frame_Format.png)]]
    920
    1021=== Preamble ===
     
    3445The number of full-rate symbols is calculated automatically by the transmitter based on the modulation rate and packet length specified by user code. The maximum number of full-rate symbols is 2047 (way more than enough for very long packets).
    3546
    36 == SISO Frame Format ==
     47The number of full-rate symbols can be zero. This enables header-only packets. User code selects this mode by transmitting a packet whose length equals the number header bytes specified during the OFDM core initialization.
    3748
    38 [[Image(OFDM/MIMO/Docs/Images:SISO_Frame_Format.png, 684)]]
     49== Checksums ==
     50The OFDM transmitter subsystem includes a checksum calculation and insertion block. This block will overwrite the last two bytes of the header with a 16-bit CRC calculated over the full contents of the base-rate symbols. The checksum block will overwrite the last four bytes of the packet with a 32-bit CRC calculated over the full packet, including the header. The 32-bit full-packet checksum is not used for header-only packets.
    3951
    40 == Multiplexing Frame Format ==
    41 
    42 [[Image(OFDM/MIMO/Docs/Images:MIMO_Frame_Format.png)]]
     52User code must accommodate these checksum insertions by leaving the corresponding bytes empty in packets loaded for transmission, and by ignoring these bytes when processing received packets.