314 research outputs found
Per-link Reliability and Rate Control: Two Facets of the SIR Meta Distribution
The meta distribution (MD) of the signal-to-interference ratio (SIR) provides
fine-grained reliability performance in wireless networks modeled by point
processes. In particular, for an ergodic point process, the SIR MD yields the
distribution of the per-link reliability for a target SIR. Here we reveal that
the SIR MD has a second important application, which is rate control.
Specifically, we calculate the distribution of the SIR threshold (equivalently,
the distribution of the transmission rate) that guarantees each link a target
reliability and show its connection to the distribution of the per-link
reliability. This connection also permits an approximate calculation of the SIR
MD when only partial (local) information about the underlying point process is
available.Comment: To appear in IEEE Wireless Communications Letters, 4 pages, 4 figure
Interference-Assisted Wireless Energy Harvesting in Cognitive Relay Network with Multiple Primary Transceivers
We consider a spectrum sharing scenario, where a secondary network coexists
with a primary network of multiple transceivers. The secondary network consists
of an energy-constrained decode-and-forward secondary relay which assists the
communication between a secondary transmitter and a destination in the presence
of the interference from multiple primary transmitters. The secondary relay
harvests energy from the received radio-frequency signals, which include the
information signal from the secondary transmitter and the primary interference.
The harvested energy is then used to decode the secondary information and
forward it to the secondary destination. At the relay, we adopt a time
switching policy due to its simplicity that switches between the energy
harvesting and information decoding over time. Specifically, we derive a
closed-form expression for the secondary outage probability under the primary
outage constraint and the peak power constraint at both secondary transmitter
and relay. In addition, we investigate the effect of the number of primary
transceivers on the optimal energy harvesting duration that minimizes the
secondary outage probability. By utilizing the primary interference as a useful
energy source in the energy harvesting phase, the secondary network achieves a
better outage performance.Comment: 6 pages, 5 figures, To be presented at IEEE GLOBECOM 201
On Information and Energy Cooperation in Energy Harvesting Cognitive Radio
This paper considers the cooperation between primary and secondary users at
information and energy levels when both users are energy harvesting nodes. In
particular, a secondary transmitter helps relaying the primary message, and in
turn, gains the spectrum access as a reward. Also, the primary transmitter
supplies energy to the secondary transmitter if the latter is
energy-constrained, which facilitates an uninterrupted cooperation. We address
this two-level cooperation over a finite horizon with the finite battery
constraint at the secondary transmitter. While promising the rate-guaranteed
service to both primary and secondary users, we aim to maximize the primary
rate. We develop an iterative algorithm that obtains the optimal offline power
policies for primary and secondary users. To acquire insights about the
structure of the optimal solution, we examine specific scenarios. Furthermore,
we investigate the effects of the secondary rate constraint and finite battery
on the primary rate and the probability of cooperation. We show that the joint
information and energy cooperation increases the chances of cooperation and
achieves significant rate gains over only information cooperation.Comment: 6 pages, 4 figures, to be presented in IEEE PIMRC 201
Block Outlier Methods for Malicious User Detection in Cooperative Spectrum Sensing
Block outlier detection methods, based on Tietjen-Moore (TM) and Shapiro-Wilk
(SW) tests, are proposed to detect and suppress spectrum sensing data
falsification (SSDF) attacks by malicious users in cooperative spectrum
sensing. First, we consider basic and statistical SSDF attacks, where the
malicious users attack independently. Then we propose a new SSDF attack, which
involves cooperation among malicious users by masking. In practice, the number
of malicious users is unknown. Thus, it is necessary to estimate the number of
malicious users, which is found using clustering and largest gap method.
However, we show using Monte Carlo simulations that, these methods fail to
estimate the exact number of malicious users when they cooperate. To overcome
this, we propose a modified largest gap method.Comment: Accepted in Proceedings of 79th IEEE Vehicular Technology
Conference-Spring (VTC-Spring), May 2014, Seoul, South Kore
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