3 research outputs found
Network Deployment for Maximal Energy Efficiency in Uplink with Multislope Path Loss
This work aims to design the uplink (UL) of a cellular network for maximal
energy efficiency (EE). Each base station (BS) is randomly deployed within a
given area and is equipped with antennas to serve user equipments
(UEs). A multislope (distance-dependent) path loss model is considered and
linear processing is used, under the assumption that channel state information
is acquired by using pilot sequences (reused across the network). Within this
setting, a lower bound on the UL spectral efficiency and a realistic circuit
power consumption model are used to evaluate the network EE. Numerical results
are first used to compute the optimal BS density and pilot reuse factor for a
Massive MIMO network with three different detection schemes, namely, maximum
ratio combining, zero-forcing (ZF) and multicell minimum mean-squared error.
The numerical analysis shows that the EE is a unimodal function of BS density
and achieves its maximum for a relatively small density of BS, irrespective of
the employed detection scheme. This is in contrast to the single-slope
(distance-independent) path loss model, for which the EE is a monotonic
non-decreasing function of BS density. Then, we concentrate on ZF and use
stochastic geometry to compute a new lower bound on the spectral efficiency,
which is then used to optimize, for a given BS density, the pilot reuse factor,
number of BS antennas and UEs. Closed- form expressions are computed from which
valuable insights into the interplay between optimization variables, hardware
characteristics, and propagation environment are obtained.Comment: 30 pages, 5 figures, 2 tables,
https://ieeexplore.ieee.org/document/8362685