Performance Analysis Of Uplink Massive MIMO And Interference Management In Heterogeneous Networks

Authors

  • P.Vetrivelan P.Rishabavarthani , V.Swetha , V.S.Anithadevi , G. Sai Tejaswi

Abstract

The uplink performance of a heterogeneous cellular network (HetNet) where both
macro and small cells base stations share the same spectrum and hence interfere with each
other. A two-tier network consisting of a canonical Massive MIMO system overlaid with a
hotspot tier of SBSs is considered. First, the achievable UL and DL SEs(Spectral Efficiency)
are analyzed, based on the channel estimation that has been carried out at the BSs based on
UL pilot transmission. Different receive combining schemes are evaluated and the impact of
spatial channel correlation and pilot contamination are revisited. The achievable SE
expressions for the UL are derived with different UL channel estimation schemes. The key
differences and similarities between the UL and DL expressions are described and the
performance of different precoding schemes is evaluated. The SE always grows with the
number of BS antennas. In the practical cases of concern, there is no upper SE limit when
using M-MMSE, despite the common belief that a fundamental upper limit exists. This holds
good for either MMSE or EW-MMSE channel estimation since the noise and all types of
interference are rejected and their impact vanishes asymptotically. Spatial correlation enables
the BS to reject the coherent interference. Other schemes are RZF and MR have asymptotic
upper SE limits determined by the coherent interference from pilot contamination, since only
the impact of noise and non-coherent interference vanish.

Published

2020-12-01

Issue

Section

Articles