December 22, 2016

Low complexity Moore-Penrose inverse for large CoMP areas with sparse massive MIMO channel matrices

  • Ahmadian Tehrani A.
  • Panzner B.
  • Sivasivaganesan R.
  • Zirwas W.

Joint transmission coordinated multipoint (JT CoMP) has been identified as a potential differentiator for future 5G radio systems due to its superior interference mitigation capabilities. Further, the combination with massive multiple-input-multiple-output (mMIMO) when a set of fixed grid of beams is used at eNodeB results in sparse overall channel matrices with a relatively low number of relevant channel components, which reduces the feedback overhead for reporting of channel state information (CSI). Although JT CoMP faces several challenges from synchronization to CSI outdating, in this paper the focus will be on complexity reduction of the precoding over large clustered cells utilizing massive MIMO. It will be derived how the typical sparse number of relevant channel components per user equipment can be exploited to reduce the number of floating point operations (FLOPs) by a factor of ten compared to state-of-the-art solutions for the calculation of the Moore Penrose pseudo inverse of the channel matrix.

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