5,975 research outputs found
Modeling Heterogeneous Network Interference Using Poisson Point Processes
Cellular systems are becoming more heterogeneous with the introduction of low
power nodes including femtocells, relays, and distributed antennas.
Unfortunately, the resulting interference environment is also becoming more
complicated, making evaluation of different communication strategies
challenging in both analysis and simulation. Leveraging recent applications of
stochastic geometry to analyze cellular systems, this paper proposes to analyze
downlink performance in a fixed-size cell, which is inscribed within a weighted
Voronoi cell in a Poisson field of interferers. A nearest out-of-cell
interferer, out-of-cell interferers outside a guard region, and cross-tier
interference are included in the interference calculations. Bounding the
interference power as a function of distance from the cell center, the total
interference is characterized through its Laplace transform. An equivalent
marked process is proposed for the out-of-cell interference under additional
assumptions. To facilitate simplified calculations, the interference
distribution is approximated using the Gamma distribution with second order
moment matching. The Gamma approximation simplifies calculation of the success
probability and average rate, incorporates small-scale and large-scale fading,
and works with co-tier and cross-tier interference. Simulations show that the
proposed model provides a flexible way to characterize outage probability and
rate as a function of the distance to the cell edge.Comment: Submitted to the IEEE Transactions on Signal Processing, July 2012,
Revised December 201
Limits on the Capacity of In-Band Full Duplex Communication in Uplink Cellular Networks
Simultaneous co-channel transmission and reception, denoted as in-band full
duplex (FD) communication, has been promoted as an attractive solution to
improve the spectral efficiency of cellular networks. However, in addition to
the self-interference problem, cross-mode interference (i.e., between uplink
and downlink) imposes a major obstacle for the deployment of FD communication
in cellular networks. More specifically, the downlink to uplink interference
represents the performance bottleneck for FD operation due to the uplink
limited transmission power and venerable operation when compared to the
downlink counterpart. While the positive impact of FD communication to the
downlink performance has been proved in the literature, its effect on the
uplink transmission has been neglected. This paper focuses on the effect of
downlink interference on the uplink transmission in FD cellular networks in
order to see whether FD communication is beneficial for the uplink transmission
or not, and if yes for which type of network. To quantify the expected
performance gains, we derive a closed form expression of the maximum achievable
uplink capacity in FD cellular networks. In contrast to the downlink capacity
which always improves with FD communication, our results show that the uplink
performance may improve or degrade depending on the associated network
parameters. Particularly, we show that the intensity of base stations (BSs) has
a more prominent effect on the uplink performance than their transmission
power
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
The Intensity Matching Approach: A Tractable Stochastic Geometry Approximation to System-Level Analysis of Cellular Networks
The intensity matching approach for tractable performance evaluation and
optimization of cellular networks is introduced. It assumes that the base
stations are modeled as points of a Poisson point process and leverages
stochastic geometry for system-level analysis. Its rationale relies on
observing that system-level performance is determined by the intensity measure
of transformations of the underlaying spatial Poisson point process. By
approximating the original system model with a simplified one, whose
performance is determined by a mathematically convenient intensity measure,
tractable yet accurate integral expressions for computing area spectral
efficiency and potential throughput are provided. The considered system model
accounts for many practical aspects that, for tractability, are typically
neglected, e.g., line-of-sight and non-line-of-sight propagation, antenna
radiation patterns, traffic load, practical cell associations, general fading
channels. The proposed approach, more importantly, is conveniently formulated
for unveiling the impact of several system parameters, e.g., the density of
base stations and blockages. The effectiveness of this novel and general
methodology is validated with the aid of empirical data for the locations of
base stations and for the footprints of buildings in dense urban environments.Comment: Submitted for Journal Publicatio
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