2,688 research outputs found
Cache-enabled Heterogeneous Cellular Networks: Comparison and Tradeoffs
Caching popular contents at base stations (BSs) is a promising way to unleash
the potential of cellular heterogeneous networks (HetNets), where backhaul has
become a bottleneck. In this paper, we compare a cache-enabled HetNet where a
tier of multi-antenna macro BSs is overlaid by a tier of helper nodes having
caches but no backhaul with a conventional HetNet where the macro BSs tier is
overlaid by a tier of pico BSs with limited-capacity backhaul. We resort
stochastic geometry theory to derive the area spectral efficiencies (ASEs) of
these two kinds of HetNets and obtain the closed-form expressions under a
special case. We use numerical results to show that the helper density is only
1/4 of the pico BS density to achieve the same target ASE, and the helper
density can be further reduced by increasing cache capacity. With given total
cache capacity within an area, there exists an optimal helper node density that
maximizes the ASE.Comment: Accepted by IEEE International Conference on Communications (ICC)
2016. This version includes detailed proofs of the proposition
Energy efficiency in heterogeneous wireless access networks
In this article, we bring forward the important aspect of energy savings in wireless access networks. We specifically focus on the energy saving opportunities in the recently evolving heterogeneous networks (HetNets), both Single- RAT and Multi-RAT. Issues such as sleep/wakeup cycles and interference management are discussed for co-channel Single-RAT HetNets. In addition to that, a simulation based study for LTE macro-femto HetNets is presented, indicating the need for dynamic energy efficient resource management schemes. Multi-RAT HetNets also come with challenges such as network integration, combined resource management and network selection. Along with a discussion on these challenges, we also investigate the performance of the conventional WLAN-first network selection mechanism in terms of energy efficiency (EE) and suggest that EE can be improved by the application of intelligent call admission control policies
On Modeling Heterogeneous Wireless Networks Using Non-Poisson Point Processes
Future wireless networks are required to support 1000 times higher data rate,
than the current LTE standard. In order to meet the ever increasing demand, it
is inevitable that, future wireless networks will have to develop seamless
interconnection between multiple technologies. A manifestation of this idea is
the collaboration among different types of network tiers such as macro and
small cells, leading to the so-called heterogeneous networks (HetNets).
Researchers have used stochastic geometry to analyze such networks and
understand their real potential. Unsurprisingly, it has been revealed that
interference has a detrimental effect on performance, especially if not modeled
properly. Interference can be correlated in space and/or time, which has been
overlooked in the past. For instance, it is normally assumed that the nodes are
located completely independent of each other and follow a homogeneous Poisson
point process (PPP), which is not necessarily true in real networks since the
node locations are spatially dependent. In addition, the interference
correlation created by correlated stochastic processes has mostly been ignored.
To this end, we take a different approach in modeling the interference where we
use non-PPP, as well as we study the impact of spatial and temporal correlation
on the performance of HetNets. To illustrate the impact of correlation on
performance, we consider three case studies from real-life scenarios.
Specifically, we use massive multiple-input multiple-output (MIMO) to
understand the impact of spatial correlation; we use the random medium access
protocol to examine the temporal correlation; and we use cooperative relay
networks to illustrate the spatial-temporal correlation. We present several
numerical examples through which we demonstrate the impact of various
correlation types on the performance of HetNets.Comment: Submitted to IEEE Communications Magazin
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