713 research outputs found
Outage and Local Throughput and Capacity of Random Wireless Networks
Outage probabilities and single-hop throughput are two important performance
metrics that have been evaluated for certain specific types of wireless
networks. However, there is a lack of comprehensive results for larger classes
of networks, and there is no systematic approach that permits the convenient
comparison of the performance of networks with different geometries and levels
of randomness.
The uncertainty cube is introduced to categorize the uncertainty present in a
network. The three axes of the cube represent the three main potential sources
of uncertainty in interference-limited networks: the node distribution, the
channel gains (fading), and the channel access (set of transmitting nodes). For
the performance analysis, a new parameter, the so-called {\em spatial
contention}, is defined. It measures the slope of the outage probability in an
ALOHA network as a function of the transmit probability at . Outage is
defined as the event that the signal-to-interference ratio (SIR) is below a
certain threshold in a given time slot. It is shown that the spatial contention
is sufficient to characterize outage and throughput in large classes of
wireless networks, corresponding to different positions on the uncertainty
cube. Existing results are placed in this framework, and new ones are derived.
Further, interpreting the outage probability as the SIR distribution, the
ergodic capacity of unit-distance links is determined and compared to the
throughput achievable for fixed (yet optimized) transmission rates.Comment: 22 pages, 6 figures. Submitted to IEEE Trans. Wireles
Interference and Outage in Clustered Wireless Ad Hoc Networks
In the analysis of large random wireless networks, the underlying node
distribution is almost ubiquitously assumed to be the homogeneous Poisson point
process. In this paper, the node locations are assumed to form a Poisson
clustered process on the plane. We derive the distributional properties of the
interference and provide upper and lower bounds for its CCDF. We consider the
probability of successful transmission in an interference limited channel when
fading is modeled as Rayleigh. We provide a numerically integrable expression
for the outage probability and closed-form upper and lower bounds.We show that
when the transmitter-receiver distance is large, the success probability is
greater than that of a Poisson arrangement. These results characterize the
performance of the system under geographical or MAC-induced clustering. We
obtain the maximum intensity of transmitting nodes for a given outage
constraint, i.e., the transmission capacity (of this spatial arrangement) and
show that it is equal to that of a Poisson arrangement of nodes. For the
analysis, techniques from stochastic geometry are used, in particular the
probability generating functional of Poisson cluster processes, the Palm
characterization of Poisson cluster processes and the Campbell-Mecke theorem.Comment: Submitted to IEEE Transactions on Information Theor
- …