Wireless mobile ATM technologies for third generation wireless communications

xtending broadband multimedia services to mobilc wireE less terminals will be the next storm in telecommunications. Wirelcss mobile ATM (wmATM) technologies provide innovative solutions to constructing a generic broadband wireless core to ensure wircless quality of service and mobility managcment. This wmATM corc also acts as a wideband open platform to support different air interfaces and multidimensional wireless systcms. The packetizcd air link helps dynamic bandwidth allocation, and thercfore improvcs wireless spectrum utilization. wmATM evolves from wircless ATM, and is armed with a direct signaling and packet-based mobile control architecture which can he attractively applied in next-generation broadband wireless systcms, including broadband wirelcss mobile and broadband wireless access networks. The IMT-2000 third-generation wireless communication system (3Gwireless) will be the major player for next-gencration broadband wireless mobile in the global telccommunications market. 3Gwireless, scheduled to start services after the year 2000, has been a hot subject of much research and many standardization activities throughout thc world. Many 3Gwireless study committees are taking the initiative to produce their own proposals for radio transmission technologies and advanced system prototypes for IMT-2000. The wmATM enhanced 3Gwireless system provides an optimal solution to implement the harmonized wireless communications required by the IMT-2000 consensus early this year. This Feature Topic presents some of the hottest issues in third-generation wireless using wmATM. In our first article, "A Lossless Handover Method for Vidco Transmission in Mobile ATM Networks and Its Subjectivc Quality Asscssment," Masaya Nishio emphasizes that cell loss is one of the most important issues in ATM mobile communication systems. He proposcs a lossless handover method in mobile ATM nctworks that can suppress delay fluctuation, and provides an evaluation of MPEG-2 image transmission with various buffer memory sizes. The second article, from Chonbuk National University of Korea, gives an overview of their proposed dynamic channcl reservation scheme, is designed to improve the utilization of wireless nctwork resources while guarantecing thc requircd QoS of handoff calls. Efficient spectrum utilization has bccome one of the essential issues in 3Gwireless systems. The next article, by Ulrich Vorncfeld, dcals with the introduction of spatial-division multiple access (SDMA) technique for ATM wirelcss systems. The authors investigate thc use of SDMA for diffcrent phases of the access control protocol and present solutions for concurrent access of more than one wireless terminal to the same timc and frequency slot. The applied model is a good reference for the access design of 3Gwireless. The Feature Topic continues with an article from Nokia which covers the WAND wmATM signaling stack implementation and its performance evaluation. Last, Janny Nu presents a very intcresting article on IPiwmATM for 3Gwireless systems, which integrates the IP technologies and next-generation wircless communications through the wmATM corc. The guest editors arc grateful to all the authors who submitted thcir contributions to this Feature Topic, and would like to express sincerc thanks to all the revicwers for their kind cooperation and contribution to raising the valuc of this Feature Topic. Our special thanks go to Andrzej Jajszczyk for his initiative to prepare this Topic and his continucd encouragement and support.