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832 WIRELESSINTERNETFigure 1: Wireless mobile data forecast. Source: Qualcomm (forecast date: 2001).Mobile users are beginning to demand from their mobile
wireless devices the types of services to which they have
become accustomed on the Internet, including Web ac-
cess, e-mail, and audio and video streaming. The forecast
of the increasing number of users of wireless services and
of the Internet is illustrated in Tables 1 and 2. It is natural
to conclude that wireless devices will become an impor-
tant access device to the Internet. However, Internet appli-
cations have vastly different characteristics and require-
ments than voice telephony, and thus are not efficiently
supported by the current cellular wireless systems, which
had been designed primarily for voice telephony applica-
tion.Use of Internet Protocol (IP) Technology
in the Cellular Network
Since current cellular wireless networks have been de-
signed and optimized for circuit-switched voice commu-
nications, the transformation of the radio access network
(RAN) has been difficult. The RAN identifies the portion
of the wireless network that handles the radio frequencies
(RF) connections, both the transfer of the voice or infor-
mation and the signaling needed to manage the so-called
air interface, including the data synchronization aspects
of the transmission. Only recently has there been work to
utilize Internet protocol (IP) in a network that connects
the base stations (BSs). To promote application indepen-
dence and to decrease costs for transport and switching,it is highly attractive to extend IP over the air interface
to the end-user equipment rather than terminating at the
RAN. This eliminates the dependencies between applica-
tions and the wireless access network and expands the
opportunity for more players to participate and develop
new applications. This should be compared with present-
day cellular services (see the section Current State of Cel-
lular Systems), which are vertically integrated and opti-
mized for voice, resulting in high performance in terms
of spectral efficiency but low flexibility in introducing new
services. The network architecture we are envisioning for
the future is shown in Figure 2, where all links (wireline
and wireless) will carry IP traffic.CURRENT STATE OF THE INTERNET
The term “Internet” refers to a wide collection of data net-
works joined together through the common use of Inter-
net protocol (IP) and its associated routing and address-
ing conventions. Each network in the collection can be
thought of as a separate autonomous system (AS) that
takes responsibility for delivering data packets within the
system however it sees fit while conforming to a standard
protocol at exchange points with other participating net-
works. Some examples of ASs include corporate networks
and ISPs. This decentralized architecture is one of the
most distinguishing characteristics of the Internet. In this
section, we review some of the more salient features of the
Internet.Table 1World Cellular Subscriber ForecastsMillions of
subscribers 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
World 136 204 307 474 728.8 988.7 1,293.0 1,580.2 1,825.3 2,029.5Source: EMC World Cellular Database, October 2001, based on actual figures to end of June 2001.