4,043 research outputs found
An Accurate and Efficient Analysis of a MBSFN Network
A new accurate analysis is presented for an OFDM-based multicast-broadcast
single-frequency network (MBSFN). The topology of the network is modeled by a
constrained random spatial model involving a fixed number of base stations
placed over a finite area with a minimum separation. The analysis is driven by
a new closed-form expression for the conditional outage probability at each
location of the network, where the conditioning is with respect to the network
realization. The analysis accounts for the diversity combining of signals
transmitted by different base stations of a given MBSFN area, and also accounts
for the interference caused by the base stations of other MBSFN areas. The
analysis features a flexible channel model, accounting for path loss, Nakagami
fading, and correlated shadowing. The analysis is used to investigate the
influence of the minimum base-station separation and provides insight regarding
the optimal size of the MBSFN areas. In order to highlight the percentage of
the network that will fail to successfully receive the broadcast, the area
below an outage threshold (ABOT) is here used and defined as the fraction of
the network that provides an outage probability (averaged over the fading) that
meets a threshold.Comment: 5 pages, 4 figures, IEEE International Conference on Acoustics,
Speech and Signal Processing (ICASSP), 2014, to appea
Analysis of Multi-Cell Downlink Cooperation with a Constrained Spatial Model
Multi-cell cooperation (MCC) mitigates intercell interference and improves
throughput at the cell edge. This paper considers a cooperative downlink,
whereby cell-edge mobiles are served by multiple cooperative base stations. The
cooperating base stations transmit identical signals over paths with
non-identical path losses, and the receiving mobile performs diversity
combining. The analysis in this paper is driven by a new expression for the
conditional outage probability when signals arriving over different paths are
combined in the presence of noise and interference, where the conditioning is
with respect to the network topology and shadowing. The channel model accounts
for path loss, shadowing, and Nakagami fading, and the Nakagami fading
parameters do not need to be identical for all paths. To study performance over
a wide class of network topologies, a random spatial model is adopted, and
performance is found by statistically characterizing the rates provided on the
downlinks. To model realistic networks, the model requires a minimum separation
among base stations. Having adopted a realistic model and an accurate analysis,
the paper proceeds to determine performance under several resource-allocation
policies and provides insight regarding how the cell edge should be defined.Comment: 6 pages, 3 figures, IEEE Global Telecommun. Conf. (GLOBECOM), 2013,
to appear. arXiv admin note: text overlap with arXiv:1210.366
Performance Analysis of Fifth-Generation Cellular Uplink
Fifth-generation cellular networks are expected to exhibit at least three
primary physical-layer differences relative to fourth-generation ones:
millimeter-wave propagation, antenna-array directionality, and densification of
base stations. In this paper, the effects of these differences on the
performance of single-carrier frequency-domain multiple-access uplink systems
with frequency hopping are assessed. A new analysis, which is much more
detailed than any other in the existing literature and accommodates actual
base-station topologies, captures the primary features of uplink
communications. Distance-dependent power-law, shadowing, and fading models
based on millimeter-wave measurements are introduced. The beneficial effects of
base-station densification, highly directional sectorization, and frequency
hopping are illustrated.Comment: 6 pages, 5 figures, IEEE Military Commun. Conf. (MILCOM), 201
Multihop Routing in Ad Hoc Networks
This paper presents a dual method of closed-form analysis and lightweight
simulation that enables an evaluation of the performance of mobile ad hoc
networks that is more realistic, efficient, and accurate than those found in
existing publications. Some features accommodated by the new analysis are
shadowing, exclusion and guard zones, and distance-dependent fading. Three
routing protocols are examined: least-delay, nearest-neighbor, and
maximum-progress routing. The tradeoffs among the path reliabilities, average
conditional delays, average conditional number of hops, and area spectral
efficiencies are examined.Comment: 6 pages, 6 figures, to appear in IEEE Military Commun. Conf.
(MILCOM), 201
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