61 research outputs found
Exploiting Frequency and Spatial Dimensions in Small Cell Wireless Networks
This paper examines the efficiency of spatial and frequency dimensions in
serving multiple users in the downlink of a small cell wireless network with
randomly deployed access points. For this purpose, the stochastic geometry
framework is incorporated, taking into account the user distribution within
each cell and the effect of sharing the available system resources to multiple
users. An analysis of performance in terms of signal-to-interference-ratio and
achieved user rate is provided that holds under the class of non-cooperative
multiple access schemes. In order to obtain concrete results, two simple
instances of multiple access schemes are considered. It is shown that
performance depends critically on both the availability of frequency and/or
spatial dimensions as well as the way they are employed. In particular,
increasing the number of available frequency dimensions alone is beneficial for
users experiencing large interference, whereas increasing spatial dimensions
without employing frequency dimensions degrades performance. However, best
performance is achieved when both dimensions are combined in serving the users.Comment: IEEE WCNC '1
Spatial Coordination Strategies in Future Ultra-Dense Wireless Networks
Ultra network densification is considered a major trend in the evolution of
cellular networks, due to its ability to bring the network closer to the user
side and reuse resources to the maximum extent. In this paper we explore
spatial resources coordination as a key empowering technology for next
generation (5G) ultra-dense networks. We propose an optimization framework for
flexibly associating system users with a densely deployed network of access
nodes, opting for the exploitation of densification and the control of overhead
signaling. Combined with spatial precoding processing strategies, we design
network resources management strategies reflecting various features, namely
local vs global channel state information knowledge exploitation, centralized
vs distributed implementation, and non-cooperative vs joint multi-node data
processing. We apply these strategies to future UDN setups, and explore the
impact of critical network parameters, that is, the densification levels of
users and access nodes as well as the power budget constraints, to users
performance. We demonstrate that spatial resources coordination is a key factor
for capitalizing on the gains of ultra dense network deployments.Comment: An extended version of a paper submitted to ISWCS'14, Special Session
on Empowering Technologies of 5G Wireless Communication
Partitioning of Distributed MIMO Systems based on Overhead Considerations
Distributed-Multiple Input Multiple Output (DMIMO) networks is a promising
enabler to address the challenges of high traffic demand in future wireless
networks. A limiting factor that is directly related to the performance of
these systems is the overhead signaling required for distributing data and
control information among the network elements. In this paper, the concept of
orthogonal partitioning is extended to D-MIMO networks employing joint
multi-user beamforming, aiming to maximize the effective sum-rate, i.e., the
actual transmitted information data. Furthermore, in order to comply with
practical requirements, the overhead subframe size is considered to be
constrained. In this context, a novel formulation of constrained orthogonal
partitioning is introduced as an elegant Knapsack optimization problem, which
allows the derivation of quick and accurate solutions. Several numerical
results give insight into the capabilities of D-MIMO networks and the actual
sum-rate scaling under overhead constraints.Comment: IEEE Wireless Communications Letter
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