Secure Simultaneous Wireless Information and Power Transfer in Multiuser STAR-RIS Aided MISO Rate Splitting Downlink

แนวคิดหลัก

The authors propose a secure STAR-RIS-aided SWIPT solution for a MISO downlink network employing rate-splitting multiple access (RSMA), where the transmitter concurrently communicates with information receivers (IRs) and sends energy to untrusted energy receivers (UERs) in the transmission and reflection spaces of the STAR-RIS.

บทคัดย่อ

The paper introduces a novel STAR-RIS-aided secure SWIPT system for downlink multiple input single output rate-splitting multiple access (RSMA) networks. The transmitter concurrently communicates with the information receivers (IRs) and sends energy to untrusted energy receivers (UERs). The UERs are also capable of wiretapping the IR streams. The authors assume that the channel state information (CSI) of the IRs is known at the transmitter, but only imperfect CSI (ICSI) is available for the UERs.
The authors exploit RSMA, where the base station splits the messages of the IRs into common and private parts. The common stream is encoded and can be decoded by all IRs, while the private messages are individually decoded by their respective IRs. The authors find the precoders and STAR-RIS configuration that maximize the achievable worst-case sum secrecy rate of the IRs under a total transmit power constraint, a sum energy constraint for the UERs, and subject to constraints on the transmission and reflection coefficients.
To tackle the non-convex and intricately coupled variables, a sub-optimal two-step iterative algorithm based on the sequential parametric convex approximation (SPCA) method is proposed. The algorithm alternately optimizes the active and passive beamforming vectors. An initialization algorithm is also provided to search for a feasible initial point and avoid potential failures.
Simulations demonstrate that the RSMA-based algorithm implemented with a STAR-RIS enhances both the rate of confidential information transmission and the total spectral efficiency, outperforming both orthogonal multiple access (OMA) and non-OMA (NOMA) schemes.

สถิติ

The total transmit power available at the base station is denoted as Pt.
The minimum sum energy required by the untrusted energy receivers (UERs) is denoted as Eth.

คำพูด

"By exploiting RSMA, the base station splits the messages of the IRs into common and private parts. The former is encoded into a common stream that can be decoded by all IRs, while the private messages are individually decoded by their respective IRs."
"We find the precoders and STAR-RIS configuration that maximizes the achievable worst-case sum secrecy rate of the IRs under a total transmit power constraint, a sum energy constraint for the UERs, and subject to constraints on the transmission and reflection coefficients."

ข้อมูลเชิงลึกที่สำคัญจาก

Secure SWIPT in the Multiuser STAR-RIS Aided MISO Rate Splitting Downlink

by Hamid Reza H... ที่ arxiv.org 05-01-2024

https://arxiv.org/pdf/2211.09081.pdf

สอบถามเพิ่มเติม

How can the proposed secure SWIPT solution be extended to handle more practical scenarios, such as imperfect CSI for the information receivers or the presence of multiple STAR-RISs

To extend the proposed secure SWIPT solution to handle more practical scenarios, such as imperfect CSI for the information receivers or the presence of multiple STAR-RISs, several modifications and enhancements can be implemented.

Imperfect CSI for Information Receivers:

Introducing a robust optimization framework that accounts for the uncertainty in the CSI of the information receivers can enhance the system's resilience to estimation errors.
Employing techniques such as robust optimization or Bayesian optimization to adapt the precoding and beamforming strategies based on the estimated CSI can improve the system's performance in the presence of imperfect information.

Multiple STAR-RISs:

Extending the system to incorporate multiple STAR-RISs introduces additional degrees of freedom and complexity.
By optimizing the precoding and beamforming across multiple STAR-RISs, the system can achieve enhanced coverage, improved energy efficiency, and increased security through diversity and redundancy.

Hybrid Beamforming:

Implementing hybrid beamforming techniques can enable the system to efficiently utilize the resources of multiple STAR-RISs while mitigating the hardware complexity associated with fully digital beamforming.
By combining analog and digital beamforming, the system can achieve a balance between performance and implementation complexity in a multi-STAR-RIS environment.

What are the potential tradeoffs between the secrecy rate, energy transfer, and spectral efficiency in the considered STAR-RIS aided RSMA network, and how can they be balanced

In the considered STAR-RIS aided RSMA network, there are inherent tradeoffs between secrecy rate, energy transfer, and spectral efficiency that need to be carefully balanced to optimize system performance.

Secrecy Rate vs. Energy Transfer:

Increasing the secrecy rate typically requires allocating more resources towards secure communication, which may reduce the resources available for energy transfer.
Balancing the tradeoff involves optimizing the power allocation between information transmission and energy harvesting to ensure both secure communication and efficient energy transfer.

Secrecy Rate vs. Spectral Efficiency:

Improving the secrecy rate may involve introducing additional coding schemes or encryption techniques, which can impact the overall spectral efficiency of the system.
Balancing this tradeoff requires optimizing the transmission strategies to maximize both secrecy rate and spectral efficiency, potentially through advanced signal processing algorithms.

Energy Transfer vs. Spectral Efficiency:

Enhancing energy transfer efficiency often involves dedicating resources specifically for power transmission, which may compete with resources allocated for data transmission and spectral efficiency.
Balancing this tradeoff involves optimizing the energy harvesting mechanisms, power control strategies, and spectral efficiency techniques to ensure optimal performance across all aspects of the system.

Can the proposed techniques be applied to other wireless communication paradigms, such as cell-free massive MIMO or integrated access and backhaul networks, to enhance their security and energy efficiency

The proposed techniques for secure SWIPT in STAR-RIS aided RSMA networks can be adapted and applied to other wireless communication paradigms to enhance security and energy efficiency.

Cell-Free Massive MIMO:

By integrating secure SWIPT principles with cell-free massive MIMO systems, it is possible to enhance the security and energy efficiency of the network.
Leveraging the distributed antennas in cell-free massive MIMO, the system can implement secure transmission strategies and efficient energy transfer mechanisms to improve overall performance.

Integrated Access and Backhaul Networks:

Applying the proposed secure SWIPT techniques to integrated access and backhaul networks can enhance the security and energy efficiency of the network infrastructure.
By optimizing the resource allocation for both access and backhaul links, the system can achieve improved spectral efficiency, energy harvesting, and secure communication capabilities.

Resource Allocation Optimization:

Utilizing advanced optimization algorithms and machine learning techniques, the proposed methods can be extended to dynamically allocate resources in complex network scenarios.
By adapting the techniques to the specific requirements of different wireless communication paradigms, the system can achieve enhanced security, energy efficiency, and overall performance.