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1.
A Review of the Development of WAP in China
In 2000, the mobile Internet was tantamount to WAP in China. In
2001, it was tantamount to the "Monternet". How about
2002 and beyond? What would it be like?
In end-1999, a brand-new concept began spreading and became a focus
of considerable attention throughout the year 2000. It referred
to WAP (Wireless Application Protocol). At the same time, the concept
of the mobile Internet also began prevailing overnight. It seemed
that people had found the gold key to the convergence of mobile
communications and the Internet, the two communications technologies
that have enjoyed the fastest growth. All the mobile operators,
handset manufacturers, network element providers and ICPs, without
exceptions, seemed to have found an enormous business opportunity.
Fuelled by the ubiquitous advertisements, the development of the
mobile Internet and WAP reached high tide and was much talked of
in the telecoms industry. What is more. The EXPO PT/COM CHINA 2000
brought the high tide to its extremity, by setting the mobile Internet
as the theme of the exhibition and highlighting the handsets with
WAP functionality exhibited by various manufacturers. China Mobile
and China Unicom, the two major mobile operators in the country,
demonstrated their WAP service at the show. Naturally, people accepted
the idea of "The mobile Internet is tantamount to WAP."
Many even thought that the wireless Internet age was approaching.
In
2001, the situation of WAP began to reverse, with lots of complaints
and criticisms against WAP made in society. In fact, these complaints
and criticisms appeared as early as in 2000, when the first WAP
users expressed their displeasure with WAP's weaknesses such as
the limited number of sites, unsatisfactory service, restrictions
on the terminals and unattractive tariffs. They wanted WAP to provide
more practical content and quicker connection, to use less restricted
terminals and to charge less.
In this context, China Mobile Communications Group launched its
"Monternet" Project, which connects the Internet and the
mobile users on a short message platform. To use the service, the
users had to keep in mind many service codes and bring with them
a handbook. Nevertheless, since it did not raise any constrains
on the handsets, could transmit information rapidly and incurred
reasonable charges, and the profitability mode it provided aroused
the interest of the ICPs, the "Monternet" made great business
success. Some people even proposed that the mobile Internet should
be tantamount to the "Monternet".
In 2002, after undergoing ups and downs, WAP seemed to have lost
in people's mind quickly like a fallen popular movie star. What
form will the Mobile Internet take in the future as a good approach
to converge boundless mobile communications and diverse Internet
services? What would WAP be like in the future? Has it reached a
dead end?
As mobile operators, we should seriously reflect on and sum up experience
drawn from the market. WAP is a failure from the perspective of
commerce, however, as a technology and standard, is it hopeless?
These are questions we should analyze and study.
2. An Analysis and Study of WAP Technology
Through an analysis of the criticisms against WAP, we can find that
despite they are objective, the technical reference points are not
completely suitable for the brand new WAP technology. The limited
number of sites and unattractive charges are problems arose in the
process of operators and ICPs deploying the service and the restrictions
on the terminals mostly refer to the small-sized displays of the
handsets and the inconvenience of entering characters through the
keyboard, which are manufacturers' problems. As to slow connectivity,
it seems to be the weakness of WAP. However, the fact is that there
is a limit of 9600 bit/s on the circuit-switched data services provided
by the GSM network and this is the very bearer mode that is currently
selected by WAP established on the network layer. This only means
that people do not accept WAP over CSD.
WAP is a set of protocols designed to allow people to receive any
kind of information, surge on Web, browse webpages, send and receive
email and even conduct e-commerce, using mobile terminals like handsets.
In order to provide Internet service to mobile users, it is necessary
to build a bridge between the mobile network and the Internet, enabling
interaction between the client side (mobile terminals) and the server.
WAP has established a unified open standard for communications between
the Internet and the mobile network. It should be stressed that
of all the protocols on the seven layers of the OSI model, WAPs
are higher-layer protocols above the network layer, which are designed
to provide interfacing for different bearer modes from above to
below.
The earliest WAP specifications were published in 1998. While WAP
was being established, the Internet had made great success worldwide
both commercially and technologically. Thus, in its establishment,
WAP borrowed and shared many basic concepts of WWW and made reference
to the successful experience and technological means. However, since
the fixed network is incomparably advantageous over its mobile counterpart
in transmission quality, bandwidth and processing capability of
the terminals, the WWW standards successfully used on the fixed
network can not be used directly on the mobile network. The principles
of WAP are: 1) to use for reference as many existing standards as
possible; 2) to adopt the layered expandable structure; 3) limited
by the bandwidth resources of the wireless network, data to be transmitted
should be compressed so as to minimize the data sent; 4) to use
effectively the limited resources of handsets; and 5) to use more
flexible user interfaces. Moreover, in order to use WAP as a tool
to implement mobile e-commerce, the establishers of WAP have taken
in consideration the improvement of security in data transmission.
The
following is the layered WAP model:
The top layer of WAP remains to be the application layer. WAE (Wireless
Application Environment) defines a series of services that can operate
on WAP equipment, and ensures that these services fit well the WAP
model and are supported by other parts of WAP. It also defines a
number of technologies such as, notably, WML (Wireless Markup Language)
and WML script; the content formats of WML, WML script and WBMP;
and WML user agent. When new functions are introduced, these technologies
will expand further. Since the actual resources used over the fixed
network can not fit the wireless environment well, the content formats
defined in WWW technologies are different from those in WAP. The
application layer of WAP uses new enhanced WWW-based content formats
so as to fit the wireless network effectively. WML and WML script
correspond to HTML and JAVA script. WBMP, which corresponds to commonly
used GIF image in the fixed network, is an optimized graphic format.
WML content, written into WML files, will be encoded into the binary
system when transmitted to WAP equipment. The WML user agent, which
is the WML browser, provides user interface for most equipment in
typical WAP equipment just like a Web browser. However, it is used
to interpret WML content. To create applications for the WML user
agent involves writing content in WML.
The session layer uses WSP (Wireless Session Protocol) and provides
two session services for the WAE layer with known interfaces. These
services refer to connection-based service from the WTP layer to
ensure data transmission and connectionless service, not to ensure
data transmission. HTTP can not operate effectively on the wireless
network and thus WAP defines a new transmission protocol, WSP, which
is a revised version of HTTP. The kernel of WSP is HTTP1.1, which
has been adapted to the wireless network. Since the bandwidth of
the wireless network is not adequate, WSP tries to send minimum
data. HTTP is based on text messages and is not efficient on the
wireless network with narrower bandwidth. Since WSP executes binary
HTTP, any data that can be encoded into the compressed binary form
will be encoded and compressed before transmission, including the
name and value of the header. Being already binary, content in WML
does not need to be processed. WSP sessions do not use TCP to ensure
data transmission, for it is neither efficient in the wireless network.
WSP is mainly used for browser application, supporting the HTTP1.1
header and its extended format, capability negotiation, binary encoding
to reduce protocol overheads and asynchronous request/response pairs,
etc.
WTP (Wireless Transaction Protocol), a transaction-based light-weighted
protocol, can operate efficiently on the wireless data network.
It executes the functionality used to support WTP browsing request/response
pairs. A request/response pair constitutes a transaction; hence
Wireless Transaction Protocol. By using datagram service (UDP or
WDP), WTP provides more reliable transmission service than pure
datagram service. WTP performs retransmission and authentication,
but unlike TCP, it has no setup/shut off function. When a transaction
is initiated for the first time, it is allocated a transaction pointer
to track the packets belonging to the same transaction. WTP performs
the reliability feature needed by WSP for request/response and reliable
PUSH operations so as to increase the reliability of datagram service.
Since it is based on messages, it can serve applications like browse
relatively well. WTP implements three categories of transactions:
Category 0 -- an unauthenticated request without response, used
for unreliable datagram service, such as unreliable PUSH service;
Category 1 -- a authenticated request without response, used for
reliable PUSH service; Category 2 -- basic request/response transaction
service. A WAP session can contain transactions of multiple categories,
however, Category 2 is mostly used for WAP browse. Such reliability
is achieved through the identification, authentication, retransmission
and deletion of transactions.
WTLS
(Wireless Transport Layer Security) of the security layer is optional.
It is used between WAP application service and datagram service.
Since the GSM network has its own security mechanism, the in-the-air
encryption algorithm is enough for most WAP services. However, to
implement safe end-to-end services with stringent requirements,
like online banking and other financial transactions, additional
security is needed. For WAP application services, security functions
are optional so that those WAP-based services that do not need security
functions do not have to add overheads. WTLS provides the following
security functions for WAP applications: encryption, to ensure that
packets between the handset and the WAP equipment can not be interpreted
by a third party; data integrity, to ensure that data transmitted
will not change; and authentication.
WDP
runs on data bearer supported by different types of network. It
is an ordinary datagram service, providing consistent service for
the higher layer and general interfaces for the protocol on the
higher layer by using the bearer network on the lower layer so as
to adapt the higher layer to the lower-layer network. This makes
the higher-layer protocol unrelated to the lower-layer bearer network.
Designed as a replacement of UDP, WDP provides the same WAP datagram
service interface as UDP. It can use the short message platform
when there is no IP traffic. In actual implementation, the handset
dials up to browse WAP content via a server, which provides IP traffic,
using UDP. WAP is rarely used in practice.
For
the bearer layer, the designers of WAP aimed at using various bearer
modes (GSM, CDMA, CDPD, etc.) to provide Internet access for the
terminals of all wireless networks. For GSM, there are several bearer
modes such as short message, CSD and GPRS. At present, the CSD mode
is mostly used for WAP browse service, but its connection speed
is slow. When China Mobile put GPRS into commercial use, the situation
will improve.
From
the above analysis, we can see that the WAP protocol set is so thoughtful
that in order to adapt to the wireless network on different layers
it has modified and improved itself by making use of WWW technologies
and reserved interfaces for various bearer modes, having taking
full consideration of factors like the limited bandwidth of the
wireless network and complex network environment. We may negate
WAP over CSD, but we can by no means negate WAP proper.
3.
The Underlying Reason for the Failure of WAP in the Market
From
the above review and analysis, we can see that although the Internet
has been introduced into mobile phone service, users are not happy
with WAP service provided in the CSD mode by the GSM network, due
to the slow connection speed of the bearer mode, the restrictions
on the handsets and the scarce WAP content. That is the objective
reason for the failure of WAP in the market.
But
the underlying reason is that the media gave over-publicity to WAP
service when various conditions are not mature. People had too many
expectations of the new service. However, in fact when they bought
WAP handsets, they disappointedly found them not as useful as they
expected. The development process of WAP represents the chaotic
situation in the market in the context of the new economy, in which
high-tech companies invent a new technology first and then try to
stimulate consumers' demand for it.
Notwithstanding,
despite the too-much-talked-about allegation of the WAP failure,
in my view that is not the ending of the story. WAP may not be as
magic and great as people thought previously, it is by no means
so bad. It takes time for WAP to rise in a real sense. This is what
most criticisms neglected. WAP, as a complete set of protocols for
Internet access by mobile users, has its own rationality. So the
protocol proper is unquestionable. It can provide people on the
move with useful information and applications when its associated
bearer network, information source and handsets are improved.
4. The Current Situation of China Mobile's WAP Network
China
Mobile is a major domestic WAP provider. In early 2000, mobile communications
companies in many economically developed provinces and cities began
to build trial WAP gateways to track the development of WAP and
at the same time rolled out WAP service for local users. In May
2000, with the completion of CMNet, China Mobile integrated the
previously widely scattered platforms into several WAP gateways
on CMNet and launched WAP service for all the data service users
in the GSM network. Later, at the end of 2000, this Chinese mobile
service giant decided to build WAP gateways in place of the trial
ones in the four nodes of Beijing Shanghai, Guangzhou and Wuhan
on 1st-phase CMNet. These new WAP gateways were put into service
and controlled on a centralized basis in the first half of 2001.
The
structure of the WAP network is shown in Figure 1.
Figure 1: Structure of WAP Network
In
the WAP network, the WAP gateways, acting as the interfaces between
the GSM network and the Internet, are most important for the provision
of WAP service in that they serve as servers for the WAP handsets
and as the client sides for the application servers on the Internet.
They are designed in line with WAP to convert HTTP to WSP.
夕2 臼奨利購峠譲耽埖撹孔萩箔方由柴
Although
WAP over CSD is not so satisfactory as expected, from statistics
we can see that there are more than 3 million requests for WAP service
of the North and the Northwest, supported by the WAP gateway in
Beijing. Just imagine how convenient it would be if WAP users can
access the Internet, browse WAP webpages worldwide and send and
receive email in any place served by China Mobile. When the restrictions
on the development of WAP are removed, the WAP service market would
grow incredibly large.
5.
Some Key Issues in Developing WAP in the Future
To
revitalize Internet access service for WAP-based mobile terminals,
we must solve the following issues.
1)
Bearer Modes
This
is a basic issue. Due to the limited speed of CSD, packet-based
access must be used if WAP is to develop. GPRS's transmission rate
can reach up to 107.2 kbit/s and will possibly reach to 171.2 kbit/s.
Besides, it can provide continuous connectivity to the Internet.
Thus it is an ideal bearer mode. The Republic of Korea has the largest
number of WAP users because it has the sole market for 64 kbit/s
service in the region, excluding Japan. This shows the importance
of connection speed. Fortunately, China Mobile's GPRS network has
begun to take shape, covering all the economically developed cities
and been put into commercial operation. The quality of the WAP traffic
transmitted over the GPRS network will be greatly improved.
2)
Handsets
WAP
handsets must have two functions. First, they must support high
speed connection, for example, GPRS. Second, they must support WAP.
In addition, they must provide large-sized screens and easy character
entry. Such terminals will be upgraded handsets. Making such handsets
will be very profitable when coming to a certain scale.
3)
Content and Applications
The
next step is to address the issue of increasing and diversifying
WAP content. WAP service should provide immediately information
that users on the move want and applications that are adaptive to
handset users such as email, emergency inquiry, B to C or C to B
business, banking and financial transactions by handset. The increase
of WAP content and diversification of WAP applications will involve
many other sectors.
4)
Profitability Modes
WAP
content and applications have to do with the profitability modes.
Sometimes, content is created not for profitability. For example,
a company may set up its own website to give publicity to its own
image and products. However, experience shows that ICPs' role in
providing information can not be neglected. Only through close cooperation
between mobile operators and ICPs, can solve the issue of profitability.
The solution seems that mobile operators collect information service
charge on behalf of ICPs through their charging platforms and charge-collecting
networks.
5)
Tariff
Such
a GPRS packet access method not only increases the connection speed
but also solves the problem of charging for the access to WAP content.
The price-sensitive GPRS users of always-on service will be charged
on the basis of data flow; they do not have to worry about the duration-based
charging system. As for the tariff, it will be established by content
providers according to actual conditions.
6)
WAP and 3G
The
general trend of mobile communications is towards 3G. When the network
evolves to 3G, the network environment WAP relied on will change
and the resources of the wireless network will be abundant. Then,
WAP and WWW technologies may possibly converge. However, mobile
networks based on GSM technology will exist for a long time. So
GPRS, which represents 2.5G, will remain vital because the main
form of information that people want to get through the Internet
is text. Therefore, WAP will still exist until 3G come to the scene.
6.
Conclusion
Looking
back on the time when the Internet just emerged, it was characterized
by slow connection speed, lack of good sites, incompatibility of
site content with browsers, high usage charges, etc. However, the
fixed network overcame these disadvantages in a short time. The
modem has upgraded from 9.6 kbit/s initially up to 56 kbit/s; the
operators have introduced faster connection modes like ISDN and
ADSL; the configuration of networked PCs has evolved from the 486
CPU to Pentium, P2, P3 and the current P4; the WWW sites on the
Internet has increased exponentially; the Internet is providing
more and more types of applications and the number of Internet users
is increasing explosively. Almost everything has changed or is changing.
What has not changed is that everything is still based on WWW technologies.
It seems that the WAP-based wireless mobile network is experiencing
the same situation as the fixed Internet experienced initially.
We believe all the problems will be solved gradually. Since WWW
is still vital, WAP-based wireless access service will not cease
to develop, since it compensates the defaults of the traditional
Internet in time and space and is suitable for the needs of the
future communications. If the restrictions on the development of
WAP are removed, WAP will win popularity again from the consumers,
who were once disappointed.
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