  This paper considers an uplink cellular system, in which each base station
(BS) is equipped with a large number of antennas to serve multiple
single-antenna user equipments (UEs) simultaneously. Uplink training with pilot
reusing is adopted to acquire the channel state information (CSI) and maximum
ratio combining (MRC) or zero forcing (ZF) reception is used for handling
multiuser interference. Leveraging stochastic geometry to model the spatial
distribution of UEs, we analyze the statistical distributions of the
interferences experienced by a typical uplink: intra-cell interference,
inter-cell interference and interference due to pilot contamination.
  For a practical but still large number of BS antennas, a key observation for
MRC reception is that it is the intra-cell interference that accounts for the
dominant portion of the total interference. In addition, the interference due
to pilot contamination tends to have a much wider distribution range than the
inter-cell interference when shadowing is strong, although their mean powers
are roughly equal. For ZF reception, on the other hand, we observe a
significant reduction of the intra-cell interference compared to MRC reception,
while the inter-cell interference and the interference due to pilot
contamination remains almost the same, thus demonstrating a substantial
superiority over MRC reception.
