Dear Colleagues,

Communication technology has brought unprecedented convenience in information transmission and acquisition. Symmetry plays an important role in the field of communication engineering. Channel symmetry between uplink and downlink has been fully utilized in current time division duplexing (TDD) communication systems. Symmetric algorithm, topology and connection have been widely applied in communication networks. However, asymmetry should be also considered in communications. In order to improve the power efficiency, asymmetric millimetre-wave arrays could be employed in future 6G communication systems. With the rapid increase of communication requirements, there are some challenging issues for both symmetric and asymmetric communications.

This Special Issue plans to give an overview of the frontiers, trends, and challenges in communication engineering and symmetry. This Special Issue is aimed at providing selected contributions on advances in both theoretical and experimental research with regard to symmetric and asymmetric communication systems and networks. Topics of interest include, but are not limited to:

• Electromagnetics, antennas, and wave propagation;
• Signal processing for communications;
• Channel measurement and modelling;
• Mobile communications including 4G, 5G, and 6G;
• Optical communications;
• Dedicated communications such as railway/power/military communications, etc.;
• Communication and networking techniques for Internet of Things (IoT);
• Applications of artificial intelligence (AI) in communications.

Dr. Tao Zhou
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.