Abstract: Disclosed are radio bearer management method and apparatus for multi-radio multi-connectivity. A method of a terminal may comprise: transmitting UP data to at least one node among an MN or SN through a first DRB; and in response to identifying a UL coverage loss in the second SN, determining switching from the first DRB to a second DRB based on a bearer switching rule.

Abstract: A method of a base station may comprise: detecting a beam failure for a terminal; in response to detecting the beam failure, transmitting a beam recovery early indicator (BREI) to the terminal based on a beam sweeping scheme; receiving a BREI response from the terminal; and identifying a preferred beam of the terminal based on reception of the BREI response.

Abstract: The present invention relates to a process for preparing isobutene-cyclodiene copolymers having a number-average molecular weight of at least 100,000 and an unsaturation of 1.about.30% by mol, characterized in that polymerization is carried out without gelation by reacting 75.about.99.5% by weight of an isobutene and 0.5.about.25% by weight of a cyclodiene or a mixture of cyclodiene as reaction materials, in a polar reaction solvent of 1.about.10 times by weight with respect to the reaction materials, wherein a catalyst solution of 0.02.about.2% by weight in the polar solvent is used in the amount of 0.2.about.2 times by weight with respect to the reaction materials, at a reaction temperature of -100.degree..about.-85.degree. C., thereby obtaining a copolymer, and then removing the residual catalyst activity at a temperature of -100.degree..about.-25.degree. C.