946 research outputs found
On the Impact of Backhaul Channel Reliability on Cooperative Wireless Networks
We study the effect of unreliable backhaul links on the performance of Coordinated Multi-Point (CoMP) techniques. CoMP has emerged as a powerful scheme to mitigate co-channel interference. Economically viable deployment of Heterogeneous Networks (HetNets) will require the use of lower-performance backhaul options, e.g. non-line-of-sight microwave links. Motivated by HetNets, a backhauling model is introduced, by assigning Link Failure Probability (LFP) to backhaul links, for the cooperative clusters. In this paper we analyze the centralized and semi-distributed CoMP architectures. We investigate the probability of deficient backhaul links reducing quality of service, by impeding transmission. By valuating the average sum rate of users within a CoMP cluster, we show how backhaul link reliability affects the performance of the cooperative cluster. We conclude, that the performance gains offered by CoMP quickly diminish, as the unreliability of the backhaul links grows
Wireless Backhaul Node Placement for Small Cell Networks
Small cells have been proposed as a vehicle for wireless networks to keep up
with surging demand. Small cells come with a significant challenge of providing
backhaul to transport data to(from) a gateway node in the core network. Fiber
based backhaul offers the high rates needed to meet this requirement, but is
costly and time-consuming to deploy, when not readily available. Wireless
backhaul is an attractive option for small cells as it provides a less
expensive and easy-to-deploy alternative to fiber. However, there are multitude
of bands and features (e.g. LOS/NLOS, spatial multiplexing etc.) associated
with wireless backhaul that need to be used intelligently for small cells.
Candidate bands include: sub-6 GHz band that is useful in non-line-of-sight
(NLOS) scenarios, microwave band (6-42 GHz) that is useful in point-to-point
line-of-sight (LOS) scenarios, and millimeter wave bands (e.g. 60, 70 and 80
GHz) that are recently being commercially used in LOS scenarios. In many
deployment topologies, it is advantageous to use aggregator nodes, located at
the roof tops of tall buildings near small cells. These nodes can provide high
data rate to multiple small cells in NLOS paths, sustain the same data rate to
gateway nodes using LOS paths and take advantage of all available bands. This
work performs the joint cost optimal aggregator node placement, power
allocation, channel scheduling and routing to optimize the wireless backhaul
network. We formulate mixed integer nonlinear programs (MINLP) to capture the
different interference and multiplexing patterns at sub-6 GHz and microwave
band. We solve the MINLP through linear relaxation and branch-and-bound
algorithm and apply our algorithm in an example wireless backhaul network of
downtown Manhattan.Comment: Invited paper at Conference on Information Science & Systems (CISS)
201
Improving Bandwidth Efficiency in E-band Communication Systems
The allocation of a large amount of bandwidth by regulating bodies in the
70/80 GHz band, i.e., the E-band, has opened up new potentials and challenges
for providing affordable and reliable Gigabit per second wireless
point-to-point links. This article first reviews the available bandwidth and
licensing regulations in the E-band. Subsequently, different propagation
models, e.g., the ITU-R and Cane models, are compared against measurement
results and it is concluded that to meet specific availability requirements,
E-band wireless systems may need to be designed with larger fade margins
compared to microwave systems. A similar comparison is carried out between
measurements and models for oscillator phase noise. It is confirmed that phase
noise characteristics, that are neglected by the models used for narrowband
systems, need to be taken into account for the wideband systems deployed in the
E-band. Next, a new multi-input multi-output (MIMO) transceiver design, termed
continuous aperture phased (CAP)-MIMO, is presented. Simulations show that
CAP-MIMO enables E-band systems to achieve fiber-optic like throughputs.
Finally, it is argued that full-duplex relaying can be used to greatly enhance
the coverage of E-band systems without sacrificing throughput, thus,
facilitating their application in establishing the backhaul of heterogeneous
networks.Comment: 16 pages, 6 Figures, Journal paper. IEEE Communication Magazine 201
Joint Access-Backhaul Perspective on Mobility Management in 5G Networks
The ongoing efforts in the research development and standardization of 5G, by
both industry and academia, have resulted in the identification of enablers
(Software Defined Networks, Network Function Virtualization, Distributed
Mobility Management, etc.) and critical areas (Mobility management,
Interference management, Joint access-backhaul mechanisms, etc.) that will help
achieve the 5G objectives. During these efforts, it has also been identified
that the 5G networks due to their high degree of heterogeneity, high QoS demand
and the inevitable density (both in terms of access points and users), will
need to have efficient joint backhaul and access mechanisms as well as enhanced
mobility management mechanisms in order to be effective, efficient and
ubiquitous. Therefore, in this paper we first provide a discussion on the
evolution of the backhaul scenario, and the necessity for joint access and
backhaul optimization. Subsequently, and since mobility management mechanisms
can entail the availability, reliability and heterogeneity of the future
backhaul/fronthaul networks as parameters in determining the most optimal
solution for a given context, a study with regards to the effect of future
backhaul/fronthaul scenarios on the design and implementation of mobility
management solutions in 5G networks has been performed.Comment: IEEE Conference on Standards for Communications & Networking,
September 2017, Helsinki, Finlan
Backhaul-aware Robust 3D Drone Placement in 5G+ Wireless Networks
Using drones as flying base stations is a promising approach to enhance the
network coverage and area capacity by moving supply towards demand when
required. However deployment of such base stations can face some restrictions
that need to be considered. One of the limitations in drone base stations
(drone-BSs) deployment is the availability of reliable wireless backhaul link.
This paper investigates how different types of wireless backhaul offering
various data rates would affect the number of served users. Two approaches,
namely, network-centric and user-centric, are introduced and the optimal 3D
backhaul-aware placement of a drone-BS is found for each approach. To this end,
the total number of served users and sum-rates are maximized in the
network-centric and user-centric frameworks, respectively. Moreover, as it is
preferred to decrease drone-BS movements to save more on battery and increase
flight time and to reduce the channel variations, the robustness of the network
is examined as how sensitive it is with respect to the users displacements.Comment: in Proc. IEEE ICC2017 Workshops, FlexNets201
Expanding cellular coverage via cell-edge deployment in heterogeneous networks: spectral efficiency and backhaul power consumption perspectives
Heterogeneous small-cell networks (HetNets) are considered to be a standard part of future mobile networks where operator/consumer deployed small-cells, such as femtocells, relays, and distributed antennas (DAs), complement the existing macrocell infrastructure. This article proposes the need-oriented deployment of smallcells and device-to-device (D2D) communication around the edge of the macrocell such that the small-cell base stations (SBSs) and D2D communication serve the cell-edge mobile users, thereby expanding the network coverage and capacity. In this context, we present competitive network configurations, namely, femto-on-edge, DA-onedge, relay-on-edge, and D2D-communication on- edge, where femto base stations, DA elements, relay base stations, and D2D communication, respectively, are deployed around the edge of the macrocell. The proposed deployments ensure performance gains in the network in terms of spectral efficiency and power consumption by facilitating the cell-edge mobile users with small-cells and D2D communication. In order to calibrate the impact of power consumption on system performance and network topology, this article discusses the detailed breakdown of the end-to-end power consumption, which includes backhaul, access, and aggregation network power consumptions. Several comparative simulation results quantify the improvements in spectral efficiency and power consumption of the D2D-communication-onedge configuration to establish a greener network over the other competitive configurations
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