163 research outputs found
Rate Balancing in Full-Duplex MIMO Two-Way Relay Networks
Maximizing the minimum rate for a full-duplex multiple-input multiple-output
(MIMO) wireless network encompassing two sources and a two-way (TW) relay
operating in a two hop manner is investigated. To improve the overall
performance, using a zero-forcing approach at the relay to suppress the
residual self-interference arising from full-duplex (FD) operation, the
underlying max-min problem is cast as an optimization problem which is
non-convex. To circumvent this issue, semidefinite relaxation technique is
employed, leading to upper and lower bound solutions for the optimization
problem. Numerical results verify that the upper and lower bound solutions
closely follow each other, showing that the proposed approach results in a
close-to-optimal solution. In addition, the impact of residual
self-interference upon the overall performance of the network in terms of the
minimum rate is illustrated by numerical results, and for low residual
self-interference scenarios the superiority of the proposed method compared to
an analogous half-duplex (HD) counterpart is shown
Passive Loop Interference Suppression in Large-Scale Full-Duplex Cellular Networks
Loop interference (LI) in wireless communications, is a notion resulting from
the full-duplex (FD) operation. In a large-scale network, FD also increases the
multiuser interference due to the large number of active wireless links that
exist. Hence, in order to realize the FD potentials, this interference needs to
be restricted. This paper presents a stochastic geometry model of FD cellular
networks where the users and base stations employ directional antennas. Based
on previous experimental results, we model the passive suppression of the LI at
each FD terminal as a function of the angle between the two antennas and show
the significant gains that can be achieved by this method. Together with the
reduction of multiuser interference resulting from antenna directionality, our
model demonstrates that FD can potentially be implemented in large-scale
directional networks.Comment: to appear in Proc. IEEE SPAWC 201
Full-Duplex MIMO Relaying Powered by Wireless Energy Transfer
We consider a full-duplex decode-and-forward system, where the wirelessly
powered relay employs the time-switching protocol to receive power from the
source and then transmit information to the destination. It is assumed that the
relay node is equipped with two sets of antennas to enable full-duplex
communications. Three different interference mitigation schemes are studied,
namely, 1) optimal 2) zero-forcing and 3) maximum ratio combining/maximum ratio
transmission. We develop new outage probability expressions to investigate
delay-constrained transmission throughput of these schemes. Our analysis show
interesting performance comparisons of the considered precoding schemes for
different system and link parameters.Comment: Accepted for IEEE International Workshop on Signal Processing
Advances in Wireless Communications (SPAWC 2015), Invited pape
Full-Duplex Relaying in MIMO-OFDM Frequency-Selective Channels with Optimal Adaptive Filtering
In-band full-duplex transmission allows a relay station to theoretically
double its spectral efficiency by simultaneously receiving and transmitting in
the same frequency band, when compared to the traditional half-duplex or
out-of-band full-duplex counterpart. Consequently, the induced
self-interference suffered by the relay may reach considerable power levels,
which decreases the signal-to-interference-plus-noise ratio (SINR) in a
decode-and-forward (DF) relay, leading to a degradation of the relay
performance. This paper presents a technique to cope with the problem of
self-interference in broadband multiple-input multiple-output (MIMO) relays.
The proposed method uses a time-domain cancellation in a DF relay, where a
replica of the interfering signal is created with the help of a recursive least
squares (RLS) algorithm that estimates the interference frequency-selective
channel. Its convergence mean time is shown to be negligible by simulation
results, when compared to the length of a typical orthogonal-frequency division
multiplexing (OFDM) sequences. Moreover, the bit-error-rate (BER) and the SINR
in a OFDM transmission are evaluated, confirming that the proposed method
extends significantly the range of self-interference power to which the relay
is resilient to, when compared with other mitigation schemes
Outage Analysis of Full-Duplex Architectures in Cellular Networks
The implementation of full-duplex (FD) radio in wireless communications is a
potential approach for achieving higher spectral efficiency. A possible
application is its employment in the next generation of cellular networks.
However, the performance of large-scale FD multiuser networks is an area mostly
unexplored. Most of the related work focuses on the performance analysis of
small-scale networks or on loop interference cancellation schemes. In this
paper, we derive the outage probability performance of large-scale FD cellular
networks in the context of two architectures: two-node and three-node. We show
how the performance is affected with respect to the model's parameters and
provide a comparison between the two architectures.Comment: to appear in Proc. IEEE VTC 2015 Spring, Glasgo
Massive MIMO Full-Duplex Relaying with Optimal Power Allocation for Independent Multipairs
With the help of an in-band full-duplex relay station, it is possible to
simultaneously transmit and receive signals from multiple users. The
performance of such system can be greatly increased when the relay station is
equipped with a large number of antennas on both transmitter and receiver
sides. In this paper, we exploit the use of massive arrays to effectively
suppress the loopback interference (LI) of a decode-and-forward relay (DF) and
evaluate the performance of the end-to-end (e2e) transmission. This paper
assumes imperfect channel state information is available at the relay and
designs a minimum mean-square error (MMSE) filter to mitigate the interference.
Subsequently, we adopt zero-forcing (ZF) filters for both detection and
beamforming. The performance of such system is evaluated in terms of bit error
rate (BER) at both relay and destinations, and an optimal choice for the
transmission power at the relay is shown. We then propose a complexity
efficient optimal power allocation (OPA) algorithm that, using the channel
statistics, computes the minimum power that satisfies the rate constraints of
each pair. The results obtained via simulation show that when both MMSE
filtering and OPA method are used, better values for the energy efficiency are
attained.Comment: Accepted to the 16th IEEE International Workshop on Signal Processing
Advances in Wireless Communications - SPAWC, Stockholm, Sweden 201
Full-Duplex MIMO Small-Cell Networks: Performance Analysis
Full-duplex small-cell relays with multiple antennas constitute a core
element of the envisioned 5G network architecture. In this paper, we use
stochastic geometry to analyze the performance of wireless networks with
full-duplex multiple-antenna small cells, with particular emphasis on the
probability of successful transmission. To achieve this goal, we additionally
characterize the distribution of the self-interference power of the full-duplex
nodes. The proposed framework reveals useful insights on the benefits of
full-duplex with respect to half-duplex in terms of network throughput
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