Increase access reliability in wireless communications

Increase access reliability in wireless communications
Increases access reliability in wireless communications

Illustration of RIS-assisted no-grant mass access in a smart factory, where a group of RIS subarrays operating in refraction mode are deployed on the factory wall. Credit: Intelligent and Converged Networks

With the emerging Internet of Things promising to power everything from smart homes to smart cities, fifth-generation wireless communication must be able to handle the demands for low delay and high reliability. To meet these demands, the researchers propose the use of reconfigurable intelligent surface technology for mass access without concession to increase access reliability in wireless communication.

The team, led by researchers from the Beijing Institute of Technology, published their findings in the journal Smart and Converged Networks.

Massive machine-type communications (mMTC) are vital for fifth generation (5G) wireless communication. In mMTC, communication between machines over wired and wireless networks takes place with little or no human intervention. The emerging Internet of Things requires this type of communication with minimal delay and high reliability. In the Internet of Things, machines, sensors, and robots must be connected to run technologies ranging from smart home security systems to wearable health monitors, wireless inventory trackers, and biometric cybersecurity scanners.

To meet the demands of Internet of Things applications demanding low latency and high reliability, no-grant random access has been proposed as a promising enabler that can simplify connection procedures and significantly reduce access delays. With no-grant random access, channel resources can be accessed without going through a handshake process.

The research team is exploring the reconfigurable intelligent surface (RIS) as a possible solution to these demands. An RIS is a programmable structure where the electrical and magnetic properties of the surface can be changed. “We propose to take advantage of the burgeoning intelligent reconfigurable surface for unsubsidized mass access operating at millimeter-wave frequencies to further increase access reliability,” said Xingyu Zhou, lead author of the study from the Advanced Research Institute of Multidisciplinary Sciences, Institute of Beijing technology.

Scientists have viewed RIS as an enabling technology for next-generation wireless communication networks due to its ability to substantially improve link quality and coverage range. A RIS consists of numerous programmable passive elements with ultra-low power consumption and low hardware costs. The RIS can reconfigure the propagation of incident electromagnetic waves by incorporating phase shifts that can be controlled independently for each element.

The team studied a scenario involving a group of RIS subarrays operating in reflection mode to aid unsubsidized mass access in a smart factory. RIS subarrays offer an additional degree of freedom and the design of suitable refraction matrices. In no-concession access models, the most challenging problems are active device detection (ADD) and channel estimation (CE), called joint ADDCE or JADDCE. By using theoretical derivation, where scientists draw conclusions from other known assumptions, the team was able to show that the challenging JADDCE problem in this context has the same mathematical form as traditional unsubsidized mass access. Therefore, they used the Efficient Approximate Message Passing (AMP) algorithm to overcome the challenges of JADDCE. Finally, to demonstrate the effectiveness and superiority of their proposed scheme, the team carried out numerical simulations to compare their scheme with the most modern solutions. His scheme improved the conditions of the access channel and improved the quality of access services in the smart factory scenario.

Looking to the future, team members see the potential for a wide range of applications. “Our proposed scheme can be widely used in the future Internet of Things network, such as smart factories or smart cities, to improve the efficiency of mass access,” Zhou said. “In future work, we will take further advantage of the powerful AI tool to implement signal processing more efficiently. In the meantime, we will evaluate the effectiveness of our proposed scheme from more dimensions and indicators.”

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More information:
Xingyu Zhou et al, Concession-Free Mass Access Assisted by Reconfigurable Smart Surface, Smart and Converged Networks (2022). DOI: 10.23919/ICN.2022.0009

Provided by Tsinghua University Press

Citation: Boosting Access Reliability in Wireless Communications (May 3, 2022) Retrieved May 3, 2022 from

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