Harri Holma has edited eight books about 3G, 4G and 5G technologies with Antti Toskala since 2001. Dr. Holma is currently working with Nokia Technology Office with a main interest in radio systems and mobile technologies.Antti Toskala joined the Nokia Research Center in 1994. He was working with WCDMA/HSPA standardization, including chairing 3GPP RAN WG1. After 3G he has worked with LTE/LTE-Advanced and 5G/5G-Advanced standards activities and he is currently heading Nokia 3GPP TSG RAN activity, with his main interest on 5G-Advanced towards 6G.Takehiro Nakamura joined NTT Laboratories in 1990. He has been engaged in the standardization activities for the WCDMA, HSPA, LTE/LTE-Advanced and 5G at ARIB in Japan since 1997.