Radio interface protocols and radio resource management procedures for 5G new radio non-terrestrial networks

In Release 17, 3GPP introduced adaptations and enhancements to the 5G new radio (NR) specification to support non-terrestrial networks (NTNs) operation. The main challenges were due to long propagation delays, especially in GEO deployments, and the movement of the satellites in LEO deployments. In this paper, we give an overview of the protocol adaptations to support NTNs. The main user plane protocol adaptations include changes to random access and hybrid automatic repeat request to due long propagation delays. The control plane protocol adaptations include a variety of mobility related enhancements for user equipment.     

Novel Function of CtXyn5A from Acetivibrio thermocellus: Dual Arabinoxylanase and Feruloyl Esterase Activity in the Same Active Site**

Enzymes’ uncharacterised side activities can have significant effects on reaction products and yields. Hence, their identification and characterisation are crucial for the development of successful reaction systems. Here, we report the presence of feruloyl esterase activity in CtXyn5A from Acetivibrio thermocellus, besides its well-known arabinoxylanase activity, for the first time. Activity analysis of enzyme variants mutated in the catalytic nucleophile, Glu279, confirmed removal of all activity for E279A and E279L, and increased esterase activity while removing xylanase activity for E279S, thus allowing the proposal that both reaction types are catalysed in the same active site in two subsequential steps. The ferulic acid substituent is cleaved off first, followed by hydrolysis of the xylan backbone. The esterase activity on complex carbohydrates was found to be higher than that of a designated ferulic acid esterase (E-FAERU). Therefore, we conclude that the enzyme exhibits a dual function rather than an esterase side activity.