  The concept of a large intelligent surface (LIS) has recently emerged as a
promising wireless communication paradigm that can exploit the entire surface
of man-made structures for transmitting and receiving information. An LIS is
expected to go beyond massive multiple-input multiple-output (MIMO) system,
insofar as the desired channel can be modeled as a perfect line-of-sight. To
understand the fundamental performance benefits, it is imperative to analyze
its achievable data rate, under practical LIS environments and limitations. In
this paper, an asymptotic analysis of the uplink data rate in an LIS-based
large antenna-array system is presented. In particular, the asymptotic LIS rate
is derived in a practical wireless environment where the estimated channel on
LIS is subject to estimation errors and interference channels are spatially
correlated Rician fading channels. Moreover, the occurrence of the channel
hardening effect is analyzed and the performance bound is asymptotically
derived for the considered LIS system. The analytical asymptotic results are
then shown to be in close agreement with the exact mutual information as the
numbers of antennas and devices increases without bounds. Moreover, the derived
ergodic rates show that noise and interference from estimation errors and the
non-line-of-sight path become negligible as the number of antennas increases.
Simulation results show that an LIS can achieve a performance that is
comparable to conventional massive MIMO with improved reliability and a
significantly reduced area for antenna deployment.
