159 research outputs found
Jamming Resistant Receivers for Massive MIMO
We design jamming resistant receivers to enhance the robustness of a massive
MIMO uplink channel against jamming. In the pilot phase, we estimate not only
the desired channel, but also the jamming channel by exploiting purposely
unused pilot sequences. The jamming channel estimate is used to construct the
linear receive filter to reduce impact that jamming has on the achievable
rates. The performance of the proposed scheme is analytically and numerically
evaluated. These results show that the proposed scheme greatly improves the
rates, as compared to conventional receivers. Moreover, the proposed schemes
still work well with stronger jamming power.Comment: Accepted in the 42nd IEEE Int. Conf. Acoust., Speech, and Signal
Process. (ICASSP2017
Attacking Massive MIMO Cognitive Radio Networks by Optimized Jamming
Massive multiple-input multiple-output (MaMIMO) and cognitive radio networks (CRNs) are two promising technologies for improving spectral efficiency of next-generation wireless communication networks. In this paper, we investigate the problem of physical layer security in the networks that jointly use both technologies, named MaMIMO-CRN. Specifically, to investigate the vulnerability of this network, we design an optimized attacking scenario to MaMIMO-CRNs by a jammer. For having the most adversary effect on the uplink transmission of the legitimate MaMIMO-CRN, we propose an efficient method for power allocation of the jammer. The legitimate network consists of a training and a data transmission phase, and both of these phases are attacked by the jammer using an optimized power split between them. The resulting power allocation problem is non-convex. We thus propose three different efficient methods for solving this problem, and we show that under some assumptions, a closed-form solution can also be obtained. Our results show the vulnerability of the MaMIMO-CRN to an optimized jammer. It is also shown that increasing the number of antennas at the legitimate network does not improve the security of the network
Sensing-Assisted Receivers for Resilient-By-Design 6G MU-MIMO Uplink
We address the resilience of future 6G MIMO communications by considering an
uplink scenario where multiple legitimate transmitters try to communicate with
a base station in the presence of an adversarial jammer. The jammer possesses
full knowledge about the system and the physical parameters of the legitimate
link, while the base station only knows the UL-channels and the
angle-of-arrival (AoA) of the jamming signals. Furthermore, the legitimate
transmitters are oblivious to the fact that jamming takes place, thus the
burden of guaranteeing resilience falls on the receiver. For this case we
derive one optimal jamming strategy that aims to minimize the rate of the
strongest user and multiple receive strategies, one based on a lower bound on
the achievable signal-to-interference-to-noise-ratio (SINR), one based on a
zero-forcing (ZF) design, and one based on a minimum SINR constraint. Numerical
studies show that the proposed anti-jamming approaches ensure that the sum rate
of the system is much higher than without protection, even when the jammer has
considerably more transmit power and even if the jamming signals come from the
same direction as those of the legitimate users.Comment: Accepted to 3rd IEEE International Symposium on Joint Communications
& Sensin
Secure Simultaneous Information and Power Transfer for Downlink Multi-user Massive MIMO
In this paper, downlink secure transmission in simultaneous information and
power transfer (SWIPT) system enabled with massive multiple-input
multiple-output (MIMO) is studied. A base station (BS) with a large number of
antennas transmits energy and information signals to its intended users, but
these signals are also received by an active eavesdropper. The users and
eavesdropper employ a power splitting technique to simultaneously decode
information and harvest energy. Massive MIMO helps the BS to focus energy to
the users and prevent information leakage to the eavesdropper. The harvested
energy by each user is employed for decoding information and transmitting
uplink pilot signals for channel estimation. It is assumed that the active
eavesdropper also harvests energy in the downlink and then contributes during
the uplink training phase. Achievable secrecy rate is considered as the
performance criterion and a closed-form lower bound for it is derived. To
provide secure transmission, the achievable secrecy rate is then maximized
through an optimization problem with constraints on the minimum harvested
energy by the user and the maximum harvested energy by the eavesdropper.
Numerical results show the effectiveness of using massive MIMO in providing
physical layer security in SWIPT systems and also show that our closed-form
expressions for the secrecy rate are accurate
Universal MIMO Jammer Mitigation via Secret Temporal Subspace Embeddings
MIMO processing enables jammer mitigation through spatial filtering, provided
that the receiver knows the spatial signature of the jammer interference.
Estimating this signature is easy for barrage jammers that transmit
continuously and with static signature, but difficult for more sophisticated
jammers: Smart jammers may deliberately suspend transmission when the receiver
tries to estimate their spatial signature, they may use time-varying
beamforming to continuously change their spatial signature, or they may stay
mostly silent and jam only specific instants (e.g., transmission of control
signals). To deal with such smart jammers, we propose MASH, the first method
that indiscriminately mitigates all types of jammers: Assume that the
transmitter and receiver share a common secret. Based on this secret, the
transmitter embeds (with a linear time-domain transform) its signal in a secret
subspace of a higher-dimensional space. The receiver applies a reciprocal
linear transform to the receive signal, which (i) raises the legitimate
transmit signal from its secret subspace and (ii) provably transforms any
jammer into a barrage jammer, which makes estimation and mitigation via MIMO
processing straightforward. We show the efficacy of MASH for data transmission
in the massive multi-user MIMO uplink.Comment: submitted to Asilomar 202
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