Wireless Communications and Mobile Computing / 2018 / Article / Tab 1

Research Article

Cognitive-Empowered Femtocells: An Intelligent Paradigm for Femtocell Networks

Table 1

Comparison between cooperative and stand-alone sensing.

Cooperative SensingStand-alone Sensing

Density Highly dependent on the density of sensing nodes. N/A
Highly dependent on independency of observation.

Heterogeneity Signals May result in the situation where secondary users N/A
submit different sensing results and conclusions due to
different perceptions of heterogeneity signals.

Communication Overhead Heavier communication overhead. N/A

Time Sensitivity Introduce additional delay from collecting sensing results Able to promptly use available sub-bands once
from sensing nodes to making the decision, identifying the availabilities.
resulting staled sensing results.

Spatial Diversity Gain Achieve spatial diversity gain with certain densities and Not able to achieve.
uncorrelated observations.

Fading Signals Higher detection sensitivity under proper density. Able to achieve detection sensitivity by using feature
detection techniques, such as cyclostationary detection,
and covariance-based detection.

Coordination Sensing and access are fully controlled by the May result in disorderly accesses to the same available
central controller. sub-bands like a swarm of bees.

Reliability Highly depends on the data fusion scheme as well as Highly depends on sensing techniques.
the credibility of sensing nodes.

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