2,797 research outputs found
Performance Analysis of a Dual-Hop Cooperative Relay Network with Co-Channel Interference
This paper analyzes the performance of a dual-hop amplify-and-forward (AF) cooperative relay network in the presence of direct link between the source and destination and multiple co-channel interferences (CCIs) at the relay. Specifically, we derive the new analytical expressions for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR) and the average symbol error rate (ASER) of the relay network. Computer simulations are given to confirm the validity of the analytical results and show the effects of direct link and interference on the considered AF relay network
Beamforming in Two-Way Fixed Gain Amplify-and-Forward Relay Systems with CCI
We analyze the outage performance of a two-way fixed gain amplify-and-forward
(AF) relay system with beamforming, arbitrary antenna correlation, and
co-channel interference (CCI). Assuming CCI at the relay, we derive the exact
individual user outage probability in closed-form. Additionally, while
neglecting CCI, we also investigate the system outage probability of the
considered network, which is declared if any of the two users is in
transmission outage. Our results indicate that in this system, the position of
the relay plays an important role in determining the user as well as the system
outage probability via such parameters as signal-to-noise imbalance, antenna
configuration, spatial correlation, and CCI power. To render further insights
into the effect of antenna correlation and CCI on the diversity and array
gains, an asymptotic expression which tightly converges to exact results is
also derived.Comment: Accepted for presentation on IEEE International Conference on
Communications (ICC 2012), Ottawa, Canada, June 201
Outage Probability of Dual-Hop Selective AF With Randomly Distributed and Fixed Interferers
The outage probability performance of a dual-hop amplify-and-forward
selective relaying system with global relay selection is analyzed for
Nakagami- fading channels in the presence of multiple interferers at both
the relays and the destination. Two different cases are considered. In the
first case, the interferers are assumed to have random number and locations.
Outage probability using the generalized Gamma approximation (GGA) in the form
of one-dimensional integral is derived. In the second case, the interferers are
assumed to have fixed number and locations. Exact outage probability in the
form of one-dimensional integral is derived. For both cases, closed-form
expressions of lower bounds and asymptotic expressions for high
signal-to-interference-plus-noise ratio are also provided. Simplified
closed-form expressions of outage probability for special cases (e.g., dominant
interferences, i.i.d. interferers, Rayleigh distributed signals) are studied.
Numerical results are presented to show the accuracy of our analysis by
examining the effects of the number and locations of interferers on the outage
performances of both AF systems with random and fixed interferers.Comment: 35 pages, 11 figures, accepted with minor revisions for publication
as a regular paper in the IEEE Transactions on Vehicular Technology on
21/09/201
Outage Probability of Dual-Hop Multiple Antenna AF Relaying Systems with Interference
This paper presents an analytical investigation on the outage performance of
dual-hop multiple antenna amplify-and-forward relaying systems in the presence
of interference. For both the fixed-gain and variable-gain relaying schemes,
exact analytical expressions for the outage probability of the systems are
derived. Moreover, simple outage probability approximations at the high signal
to noise ratio regime are provided, and the diversity order achieved by the
systems are characterized. Our results suggest that variable-gain relaying
systems always outperform the corresponding fixed-gain relaying systems. In
addition, the fixed-gain relaying schemes only achieve diversity order of one,
while the achievable diversity order of the variable-gain relaying scheme
depends on the location of the multiple antennas.Comment: Accepted to appear in IEEE Transactions on Communication
Near-Optimal Modulo-and-Forward Scheme for the Untrusted Relay Channel
This paper studies an untrusted relay channel, in which the destination sends
artificial noise simultaneously with the source sending a message to the relay,
in order to protect the source's confidential message. The traditional
amplify-and-forward (AF) scheme shows poor performance in this situation
because of the interference power dilemma: providing better security by using
stronger artificial noise will decrease the confidential message power from the
relay to the destination. To solve this problem, a modulo-and-forward (MF)
operation at the relay with nested lattice encoding at the source is proposed.
For this system with full channel state information at the transmitter (CSIT),
theoretical analysis shows that the proposed MF scheme approaches the secrecy
capacity within 1/2 bit for any channel realization, and hence achieves full
generalized security degrees of freedom (G-SDoF). In contrast, the AF scheme
can only achieve a small fraction of the G-SDoF. For this system without any
CSIT, the total outage event, defined as either connection outage or secrecy
outage, is introduced. Based on this total outage definition, analysis shows
that the proposed MF scheme achieves the full generalized secure diversity gain
(G-SDG) of order one. On the other hand, the AF scheme can only achieve a G-SDG
of 1/2 at most
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