Power Detection in 802.11a/g and 802.11b RRS feed

  • Question



    I'm seeing codes related to power detection.

    I recognized that power detection code was different in 802.11a/g and 802.11b even though functional behavior seemed same.

    In particular, to receive a signal block, 802.11b code uses SoraFetchXMMSignalBlock and 802.11a/g code uses SoraCheckSignalBlock.

    I guess that those two functions' main role is to move data in RCB to host memory.

    If so, I want to understand why different functions are used.



    Dongho Kim

    Monday, April 11, 2011 6:34 PM


  • Good question. 802.11b baseband uses inline SSE assemblies to gain better performance, so SoraFetchXMMBlock reads signal block into SSE2 registers xmm0~xmm6, and later detection module consumes data in xmm0~xmm6. In 802.11a/g, we don't use direct assembly code to implement power detection, but vector1 (SSE intrinsic at back-end) instead, so SoraCheckSignalBlock only checks if current scanned block is valid, and IQ fetching is independant. You can see codes for more details. Thanks.
    Sen Xiang (项森)
    Wednesday, April 13, 2011 2:36 PM