328 research outputs found
Integrating Sensing, Communication, and Power Transfer: Multiuser Beamforming Design
In the sixth-generation (6G) networks, massive low-power devices are expected
to sense environment and deliver tremendous data. To enhance the radio resource
efficiency, the integrated sensing and communication (ISAC) technique exploits
the sensing and communication functionalities of signals, while the
simultaneous wireless information and power transfer (SWIPT) techniques
utilizes the same signals as the carriers for both information and power
delivery. The further combination of ISAC and SWIPT leads to the advanced
technology namely integrated sensing, communication, and power transfer
(ISCPT). In this paper, a multi-user multiple-input multiple-output (MIMO)
ISCPT system is considered, where a base station equipped with multiple
antennas transmits messages to multiple information receivers (IRs), transfers
power to multiple energy receivers (ERs), and senses a target simultaneously.
The sensing target can be regarded as a point or an extended surface. When the
locations of IRs and ERs are separated, the MIMO beamforming designs are
optimized to improve the sensing performance while meeting the communication
and power transfer requirements. The resultant non-convex optimization problems
are solved based on a series of techniques including Schur complement
transformation and rank reduction. Moreover, when the IRs and ERs are
co-located, the power splitting factors are jointly optimized together with the
beamformers to balance the performance of communication and power transfer. To
better understand the performance of ISCPT, the target positioning problem is
further investigated. Simulations are conducted to verify the effectiveness of
our proposed designs, which also reveal a performance tradeoff among sensing,
communication, and power transfer.Comment: This paper has been submitted to IEEE for possible publicatio
Transmit optimization techniques for physical layer security
PhD ThesisOver the last several decades, reliable communication has received considerable
attention in the area of dynamic network con gurations and
distributed processing techniques. Traditional secure communications
mainly considered transmission cryptography, which has been developed
in the network layer. However, the nature of wireless transmission introduces
various challenges of key distribution and management in establishing
secure communication links. Physical layer security has been
recently recognized as a promising new design paradigm to provide security
in wireless networks in addition to existing conventional cryptographic
methods, where the physical layer dynamics of fading channels
are exploited to establish secure wireless links. On the other hand, with
the ever-increasing demand of wireless access users, multi-antenna transmission
has been considered as one of e ective approaches to improve
the capacity of wireless networks. Multi-antenna transmission applied
in physical layer security has extracted more and more attentions by
exploiting additional degrees of freedom and diversity gains.
In this thesis, di erent multi-antenna transmit optimization techniques
are developed for physical layer secure transmission. The secrecy rate
optimization problems (i.e., power minimization and secrecy rate maximization)
are formulated to guarantee the optimal power allocation.
First, transmit optimization for multiple-input single-output (MISO) secrecy
channels are developed to design secure transmit beamformer that
minimize the transmit power to achieve a target secrecy rate. Besides,
the associated robust scheme with the secrecy rate outage probability
constraint are presented with statistical channel uncertainty, where the
outage probability constraint requires that the achieved secrecy rate
exceeds certain thresholds with a speci c probability. Second, multiantenna
cooperative jammer (CJ) is presented to provide jamming services
that introduces extra interference to assist a multiple-input multipleoutput
(MIMO) secure transmission. Transmit optimization for this CJaided
MIMO secrecy channel is designed to achieve an optimal power
allocation. Moreover, secure transmission is achieved when the CJ introduces
charges for its jamming service based on the amount of the
interference caused to the eavesdropper, where the Stackelberg game
is proposed to handle, and the Stackelberg equilibrium is analytically
derived. Finally, transmit optimization for MISO secure simultaneous
wireless information and power transfer (SWIPT) is investigated, where
secure transmit beamformer is designed with/without the help of arti -
cial noise (AN) to maximize the achieved secrecy rate such that satisfy
the transmit power budget and the energy harvesting (EH) constraint.
The performance of all proposed schemes are validated by MATLAB
simulation results
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