83 research outputs found
Secrecy and Energy Efficiency in Massive MIMO Aided Heterogeneous C-RAN: A New Look at Interference
In this paper, we investigate the potential benefits of the massive
multiple-input multiple-output (MIMO) enabled heterogeneous cloud radio access
network (C-RAN) in terms of the secrecy and energy efficiency (EE). In this
network, both remote radio heads (RRHs) and massive MIMO macrocell base
stations (BSs) are deployed and soft fractional frequency reuse (S-FFR) is
adopted to mitigate the inter-tier interference. We first examine the physical
layer security by deriving the area ergodic secrecy rate and secrecy outage
probability. Our results reveal that the use of massive MIMO and C-RAN can
greatly improve the secrecy performance. For C-RAN, a large number of RRHs
achieves high area ergodic secrecy rate and low secrecy outage probability, due
to its powerful interference management. We find that for massive MIMO aided
macrocells, having more antennas and serving more users improves secrecy
performance. Then we derive the EE of the heterogeneous C-RAN, illustrating
that increasing the number of RRHs significantly enhances the network EE.
Furthermore, it is indicated that allocating more radio resources to the RRHs
can linearly increase the EE of RRH tier and improve the network EE without
affecting the EE of the macrocells.Comment: 26 pages, 11 figures, to appear in IEEE Journal of Selected Topics in
Signal Processin
Full-Duplex Cloud Radio Access Network: Stochastic Design and Analysis
Full-duplex (FD) has emerged as a disruptive communications paradigm for
enhancing the achievable spectral efficiency (SE), thanks to the recent major
breakthroughs in self-interference (SI) mitigation. The FD versus half-duplex
(HD) SE gain, in cellular networks, is however largely limited by the
mutual-interference (MI) between the downlink (DL) and the uplink (UL). A
potential remedy for tackling the MI bottleneck is through cooperative
communications. This paper provides a stochastic design and analysis of FD
enabled cloud radio access network (C-RAN) under the Poisson point process
(PPP)-based abstraction model of multi-antenna radio units (RUs) and user
equipments (UEs). We consider different disjoint and user-centric approaches
towards the formation of finite clusters in the C-RAN. Contrary to most
existing studies, we explicitly take into consideration non-isotropic fading
channel conditions and finite-capacity fronthaul links. Accordingly,
upper-bound expressions for the C-RAN DL and UL SEs, involving the statistics
of all intended and interfering signals, are derived. The performance of the FD
C-RAN is investigated through the proposed theoretical framework and
Monte-Carlo (MC) simulations. The results indicate that significant FD versus
HD C-RAN SE gains can be achieved, particularly in the presence of
sufficient-capacity fronthaul links and advanced interference cancellation
capabilities
- …