In wireless communication environments, multiple access interference and multipath interference are two main interferences that corrupt signal transmission. Requirements in various communication environments have led to different criteria in sequence design. Typically sequence sets used in communication should have large set sizes for supporting more users, small correlation magnitude for combating inferences, and small alphabet size for better performance. Other criteria on sequences for wireless communication include low peak-to-average power ratio (PAPR) for power efficiency and low complexity in sequence construction and implementation. Achieving optimal trade-offs among these criteria is the ultimate goal of sequence design, and it requires knowledge and techniques from digital communications, applied mathematics, and computer science.
The consortium of the SETA project has been focusing on the constructions of complementary sequences sets and pairs with zero-correlation zone, low PAPR, and optimal correlation properties. We also considered the problems of error correction in a noisy environment for reliable communications and cryptographic functions for security.
Sequences have applications in a variety of areas, ranging from the Venus Radar Project, the Mars Mariner in 1960/70s to the DNA sequence assembly, global positioning system, mobile, and wireless communications in the 21st century. Sequences are of particular importance in the CDMA systems. In recent evolution from the 4G to 5G mobile networks, one critical problem is to design multiple access schemes that can meet 5G's heterogeneous demands on high data rate, high reliability, high throughput, low latency, massive connectivity, etc. New non-orthogonal multiple access (NOMA) schemes have been proposed, resulting in new research problems and directions for the sequence design.
The SETA project will study sequences from both theoretical and applied perspectives: 1) we propose to derive new theoretical bounds on parameters of sequences and to design new (families of) sequences with optimal parameters; 2) we propose to study the emerging NOMA schemes, explore the applications of sequences in enhancing performance and security of NOMA, and design new sequence-based NOMA schemes for uplink transmissions.
The SETA project will be carried out at the Selmer Center in Secure Communications, Univ. of Bergen, which is an internationally renowned research group in sequence design, cryptography and coding theory. The project participants include both top experts and promising young researchers in the field: Guang Gong (Univ. of Waterloo, Canada), Pingzhi Fan and Yang Yang (Southwest Jiaotong Univ., China), Zilong Liu (Univ. of Essex, UK), Constanza Riera (Høyskole på Vestland, Norway) and a local partner Tor Helleseth.
The project applies for funding for one 3-year postdoc, one 3-year Ph.D. and other associated expenses during 2020.07-2024.06. The project participants will collaboratively work on the research problems, make academic visits, and disseminate the research results (approx. 30 papers) at top/leading journals, conferences, industry summits, and other public media.