It is wise for fixed operators to make use of broadband wireless access technologies,such as IEEE802.16d,to develop mobile access based on their existing fixed broadband IP networks.Mobile operators have to evolve the...It is wise for fixed operators to make use of broadband wireless access technologies,such as IEEE802.16d,to develop mobile access based on their existing fixed broadband IP networks.Mobile operators have to evolve their networks from 2G to 3G for making full use of their current resources. However,the AII-IP core network will be a general trend since broadband wireless access adopts the connectionless statistical packet multiplexing technology.Based on the introduction of IEEE802.16d,High Speed Downlink Packet Access (HSDPA) and CDMA2000 1x EV-DV technologies,this paper discusses the development trend of broadband wireless access technologies, and concludes that 3G's packet access technologies are the same as IEEE802.16d/e,and AII-IP is the goal.It emphasizes that Chinese TD-SCDMA should develop toward connectionless statistical packet multiplexing as early as possible.展开更多
Broadband Wireless Access (BWA) has become one of the major evolution trends in the fields of broadband access and mobile communications. However,some difficulties emerged during the application and industrialization ...Broadband Wireless Access (BWA) has become one of the major evolution trends in the fields of broadband access and mobile communications. However,some difficulties emerged during the application and industrialization of the BWA system,which calls for typical service models,key technology innovations and backbone support from broadband Internet. This article introduces a Broadband Wireless Multimedia (BWM) access system. It aims to build a new-type "triple play" BWA network by integrating terrestrial digital TV system and the BWA system,and by taking broadband Internet as its core network platform. A primary research shows that the new BWA system is an effective solution to the existing difficulties of BWA system. Moreover,it is quite competitive in service provision,service coverage,frequency planning,terminal power consumption and cost for network construction.展开更多
Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did no...Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did not have the resources to subscribe in comparison with even a small fraction of journals libraries in advanced countries. But the Internet and the World Wide Web initially exacerbated the gap between the rich and the poor countries, as many poor countries were slow to acquire these technologies and the infrastructure (especially bandwidth). Soon it became clear that thanks to these technologies we now have the unprecedented opportunity of having a level playing field in the matter of accessing scientific and scholarly information. Transforming this opportunity into reality is entirely in the hands of the researchers themselves. Imagine a world where every scientist places his/ her research papers, which (s)he wants to give away so others can read and make use of, in a public archive. Anyone anywhere in the world, of course having an Internet connection, can access, download, and read those papers. This is a win-win situation for all: the reader gets to read what he wants to read at very little cost; the author gains greater visibility for his work and the work reported is likely to have greater impact than if it were to be made available only through a toll-access journal. Although the logic is so simple, in reality such archives were not coming up for a very long time. In spite of the fact that computer scientists and physicists had shown about 15 years ago the great advantages of such archives. Recent studies by Alma Swan and others have shown that a very large proportion of scientists are not aware of open access and therefore what we need is focused advocacy. Even among those who know of OA, many are not depositing their papers in archives but say they would if they are asked by their bosses or their funding agencies. Clearly the ball is in the court of scientists and policy makers. OA is especially advantageous to the developing countries as the current access to literatures is poorest in these countries.展开更多
文摘It is wise for fixed operators to make use of broadband wireless access technologies,such as IEEE802.16d,to develop mobile access based on their existing fixed broadband IP networks.Mobile operators have to evolve their networks from 2G to 3G for making full use of their current resources. However,the AII-IP core network will be a general trend since broadband wireless access adopts the connectionless statistical packet multiplexing technology.Based on the introduction of IEEE802.16d,High Speed Downlink Packet Access (HSDPA) and CDMA2000 1x EV-DV technologies,this paper discusses the development trend of broadband wireless access technologies, and concludes that 3G's packet access technologies are the same as IEEE802.16d/e,and AII-IP is the goal.It emphasizes that Chinese TD-SCDMA should develop toward connectionless statistical packet multiplexing as early as possible.
文摘Broadband Wireless Access (BWA) has become one of the major evolution trends in the fields of broadband access and mobile communications. However,some difficulties emerged during the application and industrialization of the BWA system,which calls for typical service models,key technology innovations and backbone support from broadband Internet. This article introduces a Broadband Wireless Multimedia (BWM) access system. It aims to build a new-type "triple play" BWA network by integrating terrestrial digital TV system and the BWA system,and by taking broadband Internet as its core network platform. A primary research shows that the new BWA system is an effective solution to the existing difficulties of BWA system. Moreover,it is quite competitive in service provision,service coverage,frequency planning,terminal power consumption and cost for network construction.
文摘Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did not have the resources to subscribe in comparison with even a small fraction of journals libraries in advanced countries. But the Internet and the World Wide Web initially exacerbated the gap between the rich and the poor countries, as many poor countries were slow to acquire these technologies and the infrastructure (especially bandwidth). Soon it became clear that thanks to these technologies we now have the unprecedented opportunity of having a level playing field in the matter of accessing scientific and scholarly information. Transforming this opportunity into reality is entirely in the hands of the researchers themselves. Imagine a world where every scientist places his/ her research papers, which (s)he wants to give away so others can read and make use of, in a public archive. Anyone anywhere in the world, of course having an Internet connection, can access, download, and read those papers. This is a win-win situation for all: the reader gets to read what he wants to read at very little cost; the author gains greater visibility for his work and the work reported is likely to have greater impact than if it were to be made available only through a toll-access journal. Although the logic is so simple, in reality such archives were not coming up for a very long time. In spite of the fact that computer scientists and physicists had shown about 15 years ago the great advantages of such archives. Recent studies by Alma Swan and others have shown that a very large proportion of scientists are not aware of open access and therefore what we need is focused advocacy. Even among those who know of OA, many are not depositing their papers in archives but say they would if they are asked by their bosses or their funding agencies. Clearly the ball is in the court of scientists and policy makers. OA is especially advantageous to the developing countries as the current access to literatures is poorest in these countries.