A System Model for Mobile Commerce Department of Computer Science and Software Engineerin Auburn University, Auburn, AL 36849 Wen-Chen hu Department of Computer Science University of North Dakota, Grand Forks, ND 58202 wenchen @@cs und. edu Jyh-haw Yeh Department of Computer Science Boise State University, Boise, ID 83725 jhyeh @cs. boisestate edu Abstract disciplines and technologies. To lessen the difficulty, this paper will divide a mobile commerce system into six ma he emergence of wireless and mobile networks has components: (i)mobile commerce applications, (ii) de possible the introduction of electronic commerce to mobile stations, (iii) mobile middleware,(iv) wireless a new application and research subject: mobile networks, (v) wired networks, and(vi) host computers commerce. Understanding or constructing a mobile Elements in components related to mobile commerce wil commerce system is an arduous task because the system be described in detail and lists of technologies for involves a wide variety of disciplines and technologies. component construction will also be given. Related To facilitate understanding and constructing such research on mobile commerce systems can be found in the system, this article divides a mobile commerce system into article by Varshney et al. [13] six components: (i) mobile commerce applications,(ii) mobile stations, (ii) mobile middleware, (iv) wireless 1. 1 Requirements of a mobile commerce system networks, (v) wired networks, and (vi) host computers Elements in components related to mobile commerce are It is first necessary to examine what kind of features a scribed in detail and lists of technologies for componen mobile commerce system is expected to have in order to construction are also given conduct effective and efficient mobile commerce transactions and what kind of challenges may be faced in the process of developing new mobile commerce systems 1. Introduction The requirements for a mobile commerce system are 1. It should allow end users to perform mobile Mobile commerce is defined as the exchanges or commerce transactions easily, in a timely manner, buying and selling of commodities, service, or information on the Internet by using mobile handheld devices. It 2. It should allow products to be personalized or estimated that 50 million wireless phone users in the customized upon request United States will use their hand-held devices to authorize 3. It should fully support a wide range of mobile payment for premium content and physical goods. This commerce applications for content provider presents 17% of the projected total population and 26% 4. Maximum interoperability is desirable of all wireless users [15]. Many major companies have many technologies are now available begun to offer mobile commerce options for their echniques are constantly being added to mobile in addition to the electronic already provide [8]. However, it requires a tremendous 5. Program/data independence is held, that is, the effort to understand or construct a mobile commerce hange of system components does not affect the system because it involves such a wide range of existing programs/data. Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
A System Model for Mobile Commerce Chung-wei Lee Department of Computer Science and Software Engineering Auburn University, Auburn, AL 36849 chwlee@eng.auburn.edu Wen-Chen Hu Department of Computer Science University of North Dakota, Grand Forks, ND 58202 wenchen@cs.und.edu Jyh-haw Yeh Department of Computer Science Boise State University, Boise, ID 83725 jhyeh@cs.boisestate.edu Abstract The emergence of wireless and mobile networks has made possible the introduction of electronic commerce to a new application and research subject: mobile commerce. Understanding or constructing a mobile commerce system is an arduous task because the system involves a wide variety of disciplines and technologies. To facilitate understanding and constructing such a system, this article divides a mobile commerce system into six components: (i) mobile commerce applications, (ii) mobile stations, (iii) mobile middleware, (iv) wireless networks, (v) wired networks, and (vi) host computers. Elements in components related to mobile commerce are described in detail and lists of technologies for component construction are also given. 1. Introduction Mobile commerce is defined as the exchanges or buying and selling of commodities, service, or information on the Internet by using mobile handheld devices. It is estimated that 50 million wireless phone users in the United States will use their hand-held devices to authorize payment for premium content and physical goods. This represents 17% of the projected total population and 26% of all wireless users [15]. Many major companies have begun to offer mobile commerce options for their customers in addition to the electronic commerce they already provide [8]. However, it requires a tremendous effort to understand or construct a mobile commerce system because it involves such a wide range of disciplines and technologies. To lessen the difficulty, this paper will divide a mobile commerce system into six components: (i) mobile commerce applications, (ii) mobile stations, (iii) mobile middleware, (iv) wireless networks, (v) wired networks, and (vi) host computers. Elements in components related to mobile commerce will be described in detail and lists of technologies for component construction will also be given. Related research on mobile commerce systems can be found in the article by Varshney et al. [13]. 1.1. Requirements of a mobile commerce system It is first necessary to examine what kind of features a mobile commerce system is expected to have in order to conduct effective and efficient mobile commerce transactions and what kind of challenges may be faced in the process of developing new mobile commerce systems. The requirements for a mobile commerce system are: 1. It should allow end users to perform mobile commerce transactions easily, in a timely manner, and ubiquitously. 2. It should allow products to be personalized or customized upon request. 3. It should fully support a wide range of mobile commerce applications for content providers. 4. Maximum interoperability is desirable because so many technologies are now available and new techniques are constantly being added to mobile commerce systems. 5. Program/data independence is held, that is, the change of system components does not affect the existing programs/data. Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE
2. Mobile Commerce System Structure this paper. All components other than the wired networks and lists of the technologies needed for the component An electronic commerce system is an construction will be examined in the coming sections interdisciplinary subject and there are many different ways to implement it. Figure 1 shows the structure of Users traditional electronic commerce system and a typical example of such a system. The system structure includes four components Mob le handheld devices 1. Electronic commerce applications: Electronic ommerce is the buying and selling of goods and WAP services and the transfer of funds through digital ommunications Wireless newer相s 2. Client computers: Desktop computers are used by electronic commerce. whereas wireless handheld devices are used by mobile commerce 3. Wired networks: This is the main difference between electronic commerce and mobile commerce. which must also include wireless networks user request, e.g., database accesses or updating, is actually processed at a host computer, which consists of three major parts: (i) Web servers, (ii) database servers, and (iii) An MC System Structure application programs and support software. The will be examined in more detail later Figure 2. A mobile commerce system structure Users Users 3. Mobile Commerce Applications The applications of electronic commerce are already Cient computers Desktop computers widespread; mobile commerce applications not only cover these but also include new ones. For example, some tasks that are not feasible for electronic commerce. such as Host computers mobile inventory tracking and dispatching, are possible for mobile commerce. Table 1 lists some of the major mobile commerce applications [4] Mobile Category Major Applications bi retional data/control flow Commerce Mobile transactions and An EC System Structure An Implementation Education mobile classrooms and Schools and Figure 1. An e-commerce system structure Enterprise resource planning Resource management All companies Compared to an electronic commerce system, a mobile commerce system is much more complicated because Entertainment Music/video/gameEntertainment components related to mobile computing have to be included. Figure 2 shows the structure of a mobile Health care atient record Hospitals and commerce system, which consists of six components: () Inventory erce applications, (i) mobile stations, (i) tracking and Product tracking and Delivery services mobile (iv) wireless networks, (v) wired networks, and (vi) host computers, and an example of Traffic such a system that is currently possible based on existin directions, and traffic and auto technology. In mobile commerce systems, the network FTravel and nfrastructure consists of wired and wireless networks ticketing Travel management Travel industry The wired networks component has the same structure and electronic commerce system. We Table 1. Major mobile commerce applications thus devote our effort to the part of wireless networks in Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
2. Mobile Commerce System Structure An electronic commerce system is an interdisciplinary subject and there are many different ways to implement it. Figure 1 shows the structure of a traditional electronic commerce system and a typical example of such a system. The system structure includes four components: 1. Electronic commerce applications: Electronic commerce is the buying and selling of goods and services and the transfer of funds through digital communications. 2. Client computers: Desktop computers are used by electronic commerce, whereas wireless handheld devices are used by mobile commerce. 3. Wired networks: This is the main difference between electronic commerce and mobile commerce, which must also include wireless networks. 4. Host computers: A user request, e.g., database accesses or updating, is actually processed at a host computer, which consists of three major parts: (i) Web servers, (ii) database servers, and (iii) application programs and support software. These will be examined in more detail later. Figure 1. An e-commerce system structure Compared to an electronic commerce system, a mobile commerce system is much more complicated because components related to mobile computing have to be included. Figure 2 shows the structure of a mobile commerce system, which consists of six components: (i) mobile commerce applications, (ii) mobile stations, (iii) mobile middleware, (iv) wireless networks, (v) wired networks, and (vi) host computers, and an example of such a system that is currently possible based on existing technology. In mobile commerce systems, the network infrastructure consists of wired and wireless networks. The wired networks component has the same structure and implementation as in an electronic commerce system. We thus devote our effort to the part of wireless networks in this paper. All components other than the wired networks and lists of the technologies needed for the component construction will be examined in the coming sections. MC applications Wired netw orks Database servers Web servers Host computers Users User interface Wired LAN/WAN Users MC application programs Host computers association bidirectional data/control flow optional component An MC System Structure An Implemention Mobile stations Mobile handheld devices Mobile middlew are WAP Wireless networks Wireless LAN Databases Databases Figure 2. A mobile commerce system structure 3. Mobile Commerce Applications The applications of electronic commerce are already widespread; mobile commerce applications not only cover these but also include new ones. For example, some tasks that are not feasible for electronic commerce, such as mobile inventory tracking and dispatching, are possible for mobile commerce. Table 1 lists some of the major mobile commerce applications [4]. Mobile Category Major Applications Clients Commerce Mobile transactions and payments Businesses Education Mobile classrooms and labs Schools and training centers Enterprise resource planning Resource management All companies Entertainment Music/video/game downloads Entertainment industry Health care Patient record accessing Hospitals and nursing homes Inventory tracking and dispatching Product tracking and dispatching Delivery services and transportation Traffic A global positioning, directions, and traffic advisories Transportation and auto industries Travel and ticketing Travel management Travel industry and ticket sales Table 1. Major mobile commerce applications EC applications Wired netw orks Database servers Web servers Host computers Users User interface Wired LAN/WAN Users EC application programs Host computers association bidirectional data/control flow An EC System Structure An Implementation Client computers Desktop computers Databases Databases Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE
4. Mobile stations joined forces with Ericsson, Nokia, and Motorola to form a new joint venture called Symbian [12], with the aim of There are numerous mobile stations available in the establishing EPOC as the de facto operating system for market today. Table 2 lists some major mobile station mobile stations specifications, although several table entries may not be complete as some of the information is classified as 5. Mobile middleware confidential due to business considerations The term middleware refers to the software layer Vendor Processor between the operating system and the distributed System RAM/ROM applications that interact via a the networks. It translates 206 MHz Intel ompaq iPAQ MS Pocket strongarM 64MB/32 requests from mobile stations to a host computer and H3870 PC2002 adapts content from the host to the mobile station [ll] 32-bit RIsC 32-bit ARM9 6MB/8 Communicator OS 5.1. WAP and i-mode 33 MHZ Palm os Palm 1705 Motorola 8 MB/4 MB According to an article in Eurotechnology. com [ 3] 4.1 Dragonball vZ 60% of the worlds wireless internet users were using i- 66 MHZ mode, 39% were using WAP, and 1% were using Palm SONY Clie Motorola 16MB/8 middleware. Table 3 compares i-mode and WAP and PEG-NR7OV details of the middleware follow Toshiba e74 MS Pocket 400 MHz Intel 64 MB/32 WAP PC2002 Developer WAP Forum ITT DoCoMo Table 2. Some major mobile stations Function A complete mobile Internet service CHTML (Compact 4. 1. Operating systems WAP Gateway TCP/P modifications Although a wide range of mobile stations are available in the market, the operating systems, the core of mobile Key Features Weible adopted and I High at d easy to DS, Pocket PC, and Symbian Os Palm OS. The plain vanilla design of the Palm OS [9] Table 3. Two major kinds of mobile middleware has resulted in a long battery life, approximately twice that of its rivals. Palm was slower to add color features WAP (Wireless Application Protocol). WAP is an advantages of battery life, size, and weight. Palm OS 5, wireless devices to easy at allows mobile users with than its competitors because of their reluctance to lose its open, global specification tha which runs an ARM processor (TI OMAP1510), has a information and services instantly [14]. It is a very high-resolution (320x320) color screen. 16 MB of flexible sta memory, built in voice recorder, directional pad, built-in include CDPD, CDMA, GSM, PDC, PHS, TDMA, Bluetooth, and media playback capability(MP3/OGG/ FLEX, ReFLEX, IDEN, TETRA, DECT, DataTAC WAV), complete with speaker and headphone jack. Mobitex, and GRPS. It is supported by most operating Pocket pc. In 1996. microsoft launched Windows systems and was specifically engineered for mobile CE, a version of the Microsoft Windows operating system stations include Palm OS, EPOC, Windows CE, FLEXOS that is being used in a variety of embedded products from oS/9, and JavaoS. The most important technology mobile stations to ialized industrial controller and applied by WAP is probably the WAP Gateway, which is consumer electronic devices. However, it was not well mainly responsible for interfaces between the Internet and received primarily because of battery-hungry hardware the network. It functions as follows--requests from and limitations in the operating system. To solve these mobile stations are sent as a URL through the network to problems, Microsoft introduces Pocket PC [10], which the WAP Gateway; responses a whle static offers far more computing power than Windows CE server to the WaP Gateway in HTML and are then Symbian OS. EPOC16 from Psion Software is a 16- translated in WmL and sent to the mobile stations bit version of the operating system that has been available i-mode. i-mode [5] is the full-color, always-on, and eve packet-switched Internet service for cellular phones stations: EPOC32 is a 32-bit open operating system that offered by NTT DoCoMo. With i-mode, cellular phone supports preemptive multitasking. In mid-1998. Psion users get easy access to more than 60,000 Internet sites, as Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
4. Mobile Stations There are numerous mobile stations available in the market today. Table 2 lists some major mobile station specifications, although several table entries may not be complete as some of the information is classified as confidential due to business considerations. Vendor & Device Operating System Processor Installed RAM/ROM Compaq iPAQ H3870 MS Pocket PC 2002 206 MHz Intel StrongARM 32-bit RISC 64 MB/32 MB Nokia 9290 Communicator Symbian OS 32-bit ARM9 RISC 16 MB/8 MB Palm i705 Palm OS 4.1 33 MHz Motorola Dragonball VZ 8 MB/4 MB SONY Clie PEG-NR70V Palm OS 4.1 66 MHz Motorola Dragonball Super VZ 16 MB/8 MB Toshiba E740 MS Pocket PC 2002 400 MHz Intel PXA250 64 MB/32 MB Table 2. Some major mobile stations 4.1. Operating systems Although a wide range of mobile stations are available in the market, the operating systems, the core of mobile stations, are dominated by just three major brands: Palm OS, Pocket PC, and Symbian OS. Palm OS. The plain vanilla design of the Palm OS [9] has resulted in a long battery life, approximately twice that of its rivals. Palm was slower to add color features than its competitors because of their reluctance to lose its advantages of battery life, size, and weight. Palm OS 5, which runs an ARM processor (TI OMAP1510), has a high-resolution (320×320) color screen, 16 MB of memory, built in voice recorder, directional pad, built-in Bluetooth, and media playback capability (MP3/OGG/ WAV), complete with speaker and headphone jack. Pocket PC. In 1996, Microsoft launched Windows CE, a version of the Microsoft Windows operating system that is being used in a variety of embedded products from mobile stations to specialized industrial controller and consumer electronic devices. However, it was not well received primarily because of battery-hungry hardware and limitations in the operating system. To solve these problems, Microsoft introduces Pocket PC [10], which offers far more computing power than Windows CE. Symbian OS. EPOC16 from Psion Software is a 16- bit version of the operating system that has been available for several years and is embedded in many mobile stations; EPOC32 is a 32-bit open operating system that supports preemptive multitasking. In mid-1998, Psion joined forces with Ericsson, Nokia, and Motorola to form a new joint venture called Symbian [12], with the aim of establishing EPOC as the de facto operating system for mobile stations. 5. Mobile Middleware The term middleware refers to the software layer between the operating system and the distributed applications that interact via the networks. It translates requests from mobile stations to a host computer and adapts content from the host to the mobile station [11]. 5.1. WAP and i-mode According to an article in Eurotechnology.com [3], 60% of the world’s wireless Internet users were using imode, 39% were using WAP, and 1% were using Palm middleware. Table 3 compares i-mode and WAP and details of the middleware follow. WAP i-mode Developer WAP Forum NTT DoCoMo Function A protocol A complete mobile Internet service Host Language WML (Wireless Markup Language) CHTML (Compact HTML) Major Technology WAP Gateway TCP/IP modifications Key Features Widely adopted and flexible Highest number of users and easy to use Table 3. Two major kinds of mobile middleware WAP (Wireless Application Protocol). WAP is an open, global specification that allows mobile users with wireless devices to easily access and interact with information and services instantly [14]. It is a very flexible standard including most wireless networks, which include CDPD, CDMA, GSM, PDC, PHS, TDMA, FLEX, ReFLEX, iDEN, TETRA, DECT, DataTAC, Mobitex, and GRPS. It is supported by most operating systems and was specifically engineered for mobile stations include Palm OS, EPOC, Windows CE, FLEXOS, OS/9, and JavaOS. The most important technology applied by WAP is probably the WAP Gateway, which is mainly responsible for interfaces between the Internet and the network. It functions as follows—requests from mobile stations are sent as a URL through the network to the WAP Gateway; responses are sent from the Web server to the WAP Gateway in HTML and are then translated in WML and sent to the mobile stations. i-mode. i-mode [5] is the full-color, always-on, and packet-switched Internet service for cellular phones offered by NTT DoCoMo. With i-mode, cellular phone users get easy access to more than 60,000 Internet sites, as Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE
well as lized services such as e-mail, online augmented by wireless networks that support mobility for shopping and banking, ticket reservations, and restaurant end users. advice. In spring 2001, DoCoMo introduced its next generation mobile system, based on wideband CDMA 6. 1. wireless local area networks W-CDMA), which can support speeds of 384Kbps or faster, allowing users to download video images and other Devices used in wireless local area network (WLAN bandwidth-intensive content with its high-speed packet technologies are light-weight(easy to carry)and flexible data communications in network configuration. Therefore, WLANS are suitable for office networks, home networks, personal area 5.2. Implementation networks(PANS), and ad hoc networks. In a one-hop WLAN environment, where an access point(AP)acting as In a wireless environment, IP and TCP require a router or switch is a part of a wired network, mobile significant modification in order to adapt to features like devices connect directly to the AP through radio channels nobility and radio communication Data packets are relayed by an AP to the other end of a Mobile IP. The Mobile IP [ 6] defines enhancements network connection. If no APs are available, mobile that permit Internet Protocol (IP)nodes(hosts and routers) devices can form a wireless ad hoc network amon using either IPv4 or IPv6 to seamlessly"roam"among IP themselves and exchange data packets or perform business subnetworks and media types. It supports transparency transactions as necessary above the IP layer, including the maintenance of active In Table 4, major WLan technologies are compared TCP connections and UDP port bindings. Two types of in terms of maximum data transfer rate(channel mobile-IP capable router, home agent (HA)and foreign bandwidth), typical transmission range, modulation agent(FA), are defined to assist routing when the mobile techniques, and operational frequency bands. The various node is away from its home network. All datagrams combinations of modulation schemes and frequency bands destined for the mobile node are intercepted by Ha and make up different standards, which result in different tunneled to FA. FA then delivers these packets to the throughputs and coverage ranges mobile node through a care-of-address established when the mobile node is attached to Fa TCP for mobile networks. Transmission Control Modulation/ Standard Data Range(m) Protocol (TCP) was designed for reliable data transport on Rate wired networks and its parameters have been fine-tuned M Band (ghz) for such environments. As a result, when it is applied Bluetooth 5-10 GFSK/2.4 directly to mobile networks, TCP performs poorly due to 80211b 154 HR-DSSS /2.4 factors such as error-prone wireless channels, fre handoffs and disconnections. In order to optimize reliable 802\%N2 0-100OFDM/5 have been proposed for mobile networks. Yavatkar and L8onig2 data transport performance, a number of variants of TCP 50-300 OFDM/5 0-150 OFDM /2.4 Bhagawat [16] proposed an approach that splits the path Table 4. Major WLAN standards between the mobile node and the fixed node into two separate sub-paths: one over the wireless links and the other over the wired links. This approach limits the TCP In general, Bluetooth technology supports very performance degradation in a"short" wireless link limited coverage range and throughput. Thus it is only connection. Balakrishnan et al. [1] proposed a"packet suitable for applications in personal area networks. In caching scheme to reduce the TCP retransmission many parts of the world, the IEEE 802.11b(Wi-Fi)system is now the most popular wireless network and is used in overhead due to handoff. The scheme proposed in [21 offices, homes, and public spaces such as airports, utilizes the fast retransmission option immediately after shopping malls, and restaurants. However, many experts handoff is completed and shows smooth TCP performance during handoff predict that with much higher transmission speeds 802. 1la and 802.11g will replace 802. 1lb in the near future 6. Wireless Networks 6.2. Wireless wide area networks Network infrastructure provides essential voice and data communication capability for consumers and vendors Originally designed for voice-only communication, in cyberspace. Evolving from electronic commerce (EC) cellular systems are evolving from analog to digital,and to mobile commerce (MC), it is necessary for a wired from circuit-switched network infrastructure. such as the Internet. to be order to accommodate mobile commerce (data) Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
well as specialized services such as e-mail, online shopping and banking, ticket reservations, and restaurant advice. In spring 2001, DoCoMo introduced its nextgeneration mobile system, based on wideband CDMA (W-CDMA), which can support speeds of 384Kbps or faster, allowing users to download video images and other bandwidth-intensive content with its high-speed packet data communications. 5.2. Implementation In a wireless environment, IP and TCP require significant modification in order to adapt to features like mobility and radio communication. Mobile IP. The Mobile IP [6] defines enhancements that permit Internet Protocol (IP) nodes (hosts and routers) using either IPv4 or IPv6 to seamlessly “roam” among IP subnetworks and media types. It supports transparency above the IP layer, including the maintenance of active TCP connections and UDP port bindings. Two types of mobile-IP capable router, home agent (HA) and foreign agent (FA), are defined to assist routing when the mobile node is away from its home network. All datagrams destined for the mobile node are intercepted by HA and tunneled to FA. FA then delivers these packets to the mobile node through a care-of-address established when the mobile node is attached to FA. TCP for mobile networks. Transmission Control Protocol (TCP) was designed for reliable data transport on wired networks and its parameters have been fine-tuned for such environments. As a result, when it is applied directly to mobile networks, TCP performs poorly due to factors such as error-prone wireless channels, frequent handoffs and disconnections. In order to optimize reliable data transport performance, a number of variants of TCP have been proposed for mobile networks. Yavatkar and Bhagawat [16] proposed an approach that splits the path between the mobile node and the fixed node into two separate sub-paths: one over the wireless links and the other over the wired links. This approach limits the TCP performance degradation in a “short” wireless link connection. Balakrishnan et al. [1] proposed a “packet caching” scheme to reduce the TCP retransmission overhead due to handoff. The scheme proposed in [2] utilizes the fast retransmission option immediately after handoff is completed and shows smooth TCP performance during handoff. 6. Wireless Networks Network infrastructure provides essential voice and data communication capability for consumers and vendors in cyberspace. Evolving from electronic commerce (EC) to mobile commerce (MC), it is necessary for a wired network infrastructure, such as the Internet, to be augmented by wireless networks that support mobility for end users. 6.1. Wireless local area networks Devices used in wireless local area network (WLAN) technologies are light-weight (easy to carry) and flexible in network configuration. Therefore, WLANs are suitable for office networks, home networks, personal area networks (PANs), and ad hoc networks. In a one-hop WLAN environment, where an access point (AP) acting as a router or switch is a part of a wired network, mobile devices connect directly to the AP through radio channels. Data packets are relayed by an AP to the other end of a network connection. If no APs are available, mobile devices can form a wireless ad hoc network among themselves and exchange data packets or perform business transactions as necessary. In Table 4, major WLAN technologies are compared in terms of maximum data transfer rate (channel bandwidth), typical transmission range, modulation techniques, and operational frequency bands. The various combinations of modulation schemes and frequency bands make up different standards, which result in different throughputs and coverage ranges. Standard Max. Data Rate (Mbps) Typical Range (m) Modulation/ Frequency Band (GHz) Bluetooth 1 5 – 10 GFSK / 2.4 802.11b (Wi-Fi) 11 50 – 100 HR-DSSS / 2.4 802.11a 54 50 – 100 OFDM / 5 HyperLAN2 54 50 – 300 OFDM / 5 802.11g 54 50 – 150 OFDM / 2.4 Table 4. Major WLAN standards In general, Bluetooth technology supports very limited coverage range and throughput. Thus it is only suitable for applications in personal area networks. In many parts of the world, the IEEE 802.11b (Wi-Fi) system is now the most popular wireless network and is used in offices, homes, and public spaces such as airports, shopping malls, and restaurants. However, many experts predict that with much higher transmission speeds, 802.11a and 802.11g will replace 802.11b in the near future. 6.2. Wireless wide area networks Originally designed for voice-only communication, cellular systems are evolving from analog to digital, and from circuit-switched to packet-switched networks, in order to accommodate mobile commerce (data) Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE
applications. Table 5 lists a classification of standards in targets, browsers or microbrowser, serve. the first generation(IG), second generations(2G, 2.5G), component is similar to that used n electronic and third generation(3G) wireless cellular networks. IG commerce system. Most of the mobile commerce ystems such as the advanced mobile phone system application programs reside in this component, except for (AMPS)and total access control system(TACS)are some client-side programs such as cookies. It contains becoming obsolete, and thus will not play a significant three major components: a Web server, a database server role in mobile commerce systems. The global system for and application programs and support software mobile communications (GSM) and its enhancement Web servers. a Web server is a server-side general packet radio service( GPRS) have mainly been application program that runs on a host computer and version--enhanced data for global evolution(ED graded Manages the Web pages stored on the Web sites database developed and deployed in Europe. GPRS can support ma capable of supporting 384 kbps. In the U.S., wireless Apache, and commercial packages from Microsoft, operators use time division multiple access(TDMA)and Netscape, and others. Since April 1996, Apache has been code division multiple access( cdma)technologiEs in the most popular Http server on the Internet in May their cellular networks 1999, it was running on 57% of all web servers. It was developed in early 1995, based on code and ideas found in Generation Radio Switching Standards themostpopularhttpserverofthetimeNcsahttpd 1.3. It has since evolved to rival(and probably surpass) almost any other Unix based Http server in terms of Circuit- AMPS functionality and speed. It features highly configurable Digital switched error messages, DBM-based authentication databases, and contro Circuit- GSM content negotiation witched Database servers. Other than the server-side Digital Packet database servers, a growing trend is to provide a mobile CDMA switched database or an embedded database to a handheld device with a wide range of data-processing functionality. The 2.5G Digital Packet- switched EDGE functionality is frequently very sophisticated, and the flat Packe CDMA2000 file system that comes with these devices may not be able to adequately handle and manipulate data. Embedded databases have very small footprints, and must be able to Table 5. Major cellular wireless networks run without the services of a database administrator and accommodate the low-bandwidth constraints of a Currently, most of the cellular wireless networks in wireless-handheld network. Some leading embedded- the world follow 2G or 2. 5G standards. There is no doubt databases are Progress Software databases, Sybase's that in the near future, 3G systems with quality-of-service Anywhere products, and Ardent Software's DataStage [7] (Qos) capability will dominate wireless cellular services. programs and support software. Web The two main standards of 3G are Wideband CDMa and database servers are mandatory for mobile commerce (WCDMA), proposed by Ericsson, and CDMA2000, systems; application programs handle all server-side proposed by Qualcomm. They both use direct sequence processing. However, to facilitate mobile commerce spread spectrum (DSSS) in a 5-MHz bandwidth. applications, some other support software is needed. For Technical differences between them include a different example, various programming languages, including Perl chip rate, frame time, spectrum used, and time Java, Visual Basic, C/C++, etc, and the CGI( Common synchronization mechanism. The WCDMA system can Gateway Interface) for transferring information between inter-network with GSM networks and was strongly Web server and a CGI program are necessary Universal Mobile Telecommunications System (UMTS). 8. St CDMA2000 is backward-compatible with IS-95, which is widely deployed in the U.S The emerging wireless and mobile networks have extended electronic commerce to another research and 7. Host Computers application subject: mobile commerce. A mobile commerce system involves a range of disciplines and A host computer produces and stores all the technologies. This level of complexity makes information for mobile commerce applications. Because understanding and constructing a mobile commerce it is the mobile commerce application programs, rather system an arduous task. To facilitate this process, this than the host computers themselves, that are aware of the Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
applications. Table 5 lists a classification of standards in the first generation (1G), second generations (2G, 2.5G), and third generation (3G) wireless cellular networks. 1G systems such as the advanced mobile phone system (AMPS) and total access control system (TACS) are becoming obsolete, and thus will not play a significant role in mobile commerce systems. The global system for mobile communications (GSM) and its enhancement general packet radio service (GPRS) have mainly been developed and deployed in Europe. GPRS can support data rates of only about 100 kbps, but its upgraded capable of supporting 384 kbps. In the U.S., wireless operators use time division multiple access (TDMA) and code division multiple access (CDMA) technologies in their cellular networks. Generation Radio Channels Switching Technique Standards (Examples) 1G Analog voice; Digital control Circuitswitched AMPS TACS Circuitswitched GSM TDMA 2G Digital Packetswitched CDMA 2.5G Digital Packetswitched GPRS EDGE 3G Digital Packetswitched CDMA2000 WCDMA Table 5. Major cellular wireless networks Currently, most of the cellular wireless networks in the world follow 2G or 2.5G standards. There is no doubt that in the near future, 3G systems with quality-of-service (QoS) capability will dominate wireless cellular services. The two main standards of 3G are Wideband CDMA (WCDMA), proposed by Ericsson, and CDMA2000, proposed by Qualcomm. They both use direct sequence spread spectrum (DSSS) in a 5-MHz bandwidth. Technical differences between them include a different chip rate, frame time, spectrum used, and time synchronization mechanism. The WCDMA system can inter-network with GSM networks and was strongly supported by the European Union, which called it Universal Mobile Telecommunications System (UMTS). CDMA2000 is backward-compatible with IS-95, which is widely deployed in the U.S. 7. Host Computers A host computer produces and stores all the information for mobile commerce applications. Because it is the mobile commerce application programs, rather than the host computers themselves, that are aware of the targets, browsers or microbrowsers, they serve, this component is similar to that used in an electronic commerce system. Most of the mobile commerce application programs reside in this component, except for some client-side programs such as cookies. It contains three major components: a Web server, a database server, and application programs and support software. Web servers. A Web server is a server-side application program that runs on a host computer and manages the Web pages stored on the Web site’s database. There are many Web server software applications, including public domain software from NCSA and Apache, and commercial packages from Microsoft, Netscape, and others. Since April 1996, Apache has been the most popular HTTP server on the Internet; in May 1999, it was running on 57% of all web servers. It was developed in early 1995, based on code and ideas found in the most popular HTTP server of the time, NCSA httpd 1.3. It has since evolved to rival (and probably surpass) almost any other Unix based HTTP server in terms of functionality and speed. It features highly configurable error messages, DBM-based authentication databases, and content negotiation. Database servers. Other than the server-side database servers, a growing trend is to provide a mobile database or an embedded database to a handheld device with a wide range of data-processing functionality. The functionality is frequently very sophisticated, and the flat file system that comes with these devices may not be able to adequately handle and manipulate data. Embedded databases have very small footprints, and must be able to run without the services of a database administrator and accommodate the low-bandwidth constraints of a wireless-handheld network. Some leading embeddeddatabases are Progress Software databases, Sybase’s Anywhere products, and Ardent Software’s DataStage [7]. Application programs and support software. Web and database servers are mandatory for mobile commerce systems; application programs handle all server-side processing. However, to facilitate mobile commerce applications, some other support software is needed. For example, various programming languages, including Perl, Java, Visual Basic, C/C++, etc., and the CGI (Common Gateway Interface) for transferring information between a Web server and a CGI program are necessary. 8. Summary The emerging wireless and mobile networks have extended electronic commerce to another research and application subject: mobile commerce. A mobile commerce system involves a range of disciplines and technologies. This level of complexity makes understanding and constructing a mobile commerce system an arduous task. To facilitate this process, this Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE
divided a mobile commerce system into six 9 Acknowledgments components, which can be summarized as follows 1. Mobile commerce applications: Electronic commerce This work was partly supported by Auburn University applications are already broad. Mobile commerce Competitive Research Grant and the Samuel Ginn College applications not only cover the existing applications of engineering but also include new applications, which can be performed at anytime and from anywhere by using 10. References nobile computing technology 2. Mobile stations: Mobile stations are limited by their [1 H. Balakrishnan, small screens, limited memory, limited processing power, and low battery power, and suffer from Proceedings of the I wireless network transmission problems. Numerous Mobile Computing and 二 mobile stations. such as PDAs or Web-enabled California. 1995 cellular phones, are available in the market, but most [2] R. Caceres and L. Iftode. Improving the performance of use one of three major operating systems: Palm Os reliable transport protocols in mobile com Microsoft Pocket PC, and Symbian OS. At this nvironment. In T Imielinski and H. Korth. editors moment, Palm OS leads the market, however it faces Computing, pages 207-228, Kluwer Academic Publishers, a serious challenge from Pocket PC. [3] Frequently asked questions about NTT-DoCoMo's i-mode 3. Mobile middleware: WaP and i-mode are the two najor kinds of mobile middleware. WAP is widely Eurotechnology. Retrieved December 16, 2002 from http://www.eurotechnology.com/imode/faq.html adopted and flexible, while i-mode has the highest [4] P. Gordon and J. Gebauer. M-commerce: Revolution number of users and is easy to use. It is difficult to inertia evolution. Working Paper 01-WP-1038, predict which middleware will dominate the market University of California, Berkeley, 2001 in the future: it is more likely that the two will be 5] i-mode. NTT-DoCoMo. Retrieved November 28,2002 blended somehow at some point in the future fromhttp://www.nttdocomo.com 4. Wireless and wired networks: Wireless LAN. maN [ 6] IP routing for wireless/mobile hosts(MobileIP).The IETF and WAN are major components used to provide Working Group. Retrieved November 6, 2002 from http://www.ietf.org/html.charters/'mobileip-charter.html radio communication channels so that mobile service [7] S. Ortiz, Jr. Embedded databases come is possible. In the WLAn category, the Wi-Fi EEE Computer,333):16-19,2000 standard with 11 Mbps throughput dominates the [8] Over 50% of large U.S. enterprises plan to implement a current market. It is expected that standards with ireless/mobile solution by 2003. The Yankee Group, much higher transmission speeds, such as IEEE December 10. 2002 from 802.1la and 802.11g, will replace Wi-Fi in the near future. Compared to WLANS, cellular systems can lease_detail jsp? ID=PressReleases/news_09102002_wmec provide longer transmission distances and greater 9 Palm OS. Retrieved December 22, 2002 from radio coverage, but suffer from the drawback of much http://www.palmsource.com/palmos/ lower bandwidth(less than 1 Mbps). In the latest [10] Pocket PC. Retrieved November 25, 2002, from trend for cellular systems, 3G standards supporting http://www.microsoft.com/mobile/pocketpc/ wireless multimedia and high-bandwidth services are [11]S. Saha, M. Jamtgaard, and J. Villasenor. Bringing the WCDMA and wireless Internet to mobile devices. IEEE Computer, CDMA2000 are likely to dominate the market in the 4(6:54-58,2001 future [12] Symbian. Retrieved December 10, 2002 from 5. Host computers: Host computers produce and store http://www.symbian.com/ all the information needed for mobile commerce [131 U. Varshney, R. J. Vetter, and R. Kalakota. Mobile applications, and most application programs can be mmerce: A new frontier. IEEE Computer, 33(10): 3 2000. found here. They include three major components: [14] WAP: Wireless Application Protocol Web servers, database servers, and application Retrieved November 21. 2002 t Mobile and support software http://www.wapforum.org/ Another important issue for mobile commerce is [ 15] The Yankee Group publishes U.s. mobile commerce mobile security and payment. Security issues(includin forecast. Reuters, 2001. Retreived December 16, 2002 payment)include data reliability, integrity, confidentiality, http://about.reuters.com/newsreleases/art_31 and authentication and are usually an important part of 00l_id765 asp mplementation in wireless protocols/systems. Solutions [16R. Yavatkar and N. Bhagawat. Improving end-to-end are updated frequently, due to the lack of a comprehensive of tcP over mobile internetworks. In wireless security infrastructure and standard. A unified Proceedings of the Workshop on Mobile Computing and Applications, Santa Cruz, California, 1994 approach has not yet emerged Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops(ICDCSw03 SOCIETY 0-7695-1921-003$1700@2003lEEE
paper divided a mobile commerce system into six components, which can be summarized as follows: 1. Mobile commerce applications: Electronic commerce applications are already broad. Mobile commerce applications not only cover the existing applications, but also include new applications, which can be performed at anytime and from anywhere by using mobile computing technology. 2. Mobile stations: Mobile stations are limited by their small screens, limited memory, limited processing power, and low battery power, and suffer from wireless network transmission problems. Numerous mobile stations, such as PDAs or Web-enabled cellular phones, are available in the market, but most use one of three major operating systems: Palm OS, Microsoft Pocket PC, and Symbian OS. At this moment, Palm OS leads the market, however it faces a serious challenge from Pocket PC. 3. Mobile middleware: WAP and i-mode are the two major kinds of mobile middleware. WAP is widely adopted and flexible, while i-mode has the highest number of users and is easy to use. It is difficult to predict which middleware will dominate the market in the future; it is more likely that the two will be blended somehow at some point in the future. 4. Wireless and wired networks: Wireless LAN, MAN, and WAN are major components used to provide radio communication channels so that mobile service is possible. In the WLAN category, the Wi-Fi standard with 11 Mbps throughput dominates the current market. It is expected that standards with much higher transmission speeds, such as IEEE 802.11a and 802.11g, will replace Wi-Fi in the near future. Compared to WLANs, cellular systems can provide longer transmission distances and greater radio coverage, but suffer from the drawback of much lower bandwidth (less than 1 Mbps). In the latest trend for cellular systems, 3G standards supporting wireless multimedia and high-bandwidth services are beginning to be deployed. WCDMA and CDMA2000 are likely to dominate the market in the future. 5. Host computers: Host computers produce and store all the information needed for mobile commerce applications, and most application programs can be found here. They include three major components: Web servers, database servers, and application programs and support software. Another important issue for mobile commerce is mobile security and payment. Security issues (including payment) include data reliability, integrity, confidentiality, and authentication and are usually an important part of implementation in wireless protocols/systems. Solutions are updated frequently, due to the lack of a comprehensive wireless security infrastructure and standard. A unified approach has not yet emerged. 9. Acknowledgments This work was partly supported by Auburn University Competitive Research Grant and the Samuel Ginn College of Engineering. 10. References [1] H. Balakrishnan, S. Seshan, E. Amir, and R. Katz. Improving TCP/IP performance over wireless networks. In Proceedings of the 1st ACM International Conference on Mobile Computing and Networking (MobiCom), Berkeley, California, 1995. [2] R. Caceres and L. Iftode. Improving the performance of reliable transport protocols in mobile computing environment. In T. Imielinski and H. Korth, editors, Mobile Computing, pages 207–228, Kluwer Academic Publishers, 1996. [3] Frequently asked questions about NTT-DoCoMo’s i-mode. Eurotechnology. Retrieved December 16, 2002 from http://www.eurotechnology.com/imode/faq.html [4] P. Gordon and J. Gebauer. M-commerce: Revolution + inertia = evolution. Working Paper 01-WP-1038, University of California, Berkeley, 2001. [5] i-mode. NTT-DoCoMo. Retrieved November 28, 2002 from http://www.nttdocomo.com/ [6] IP routing for wireless/mobile hosts (MobileIP). The IETF Working Group. Retrieved November 6, 2002 from http://www.ietf.org/html.charters/mobileip-charter.html [7] S. Ortiz, Jr. Embedded databases come out of hiding. IEEE Computer, 33(3):16-19, 2000. [8] Over 50% of large U.S. enterprises plan to implement a wireless/mobile solution by 2003. The Yankee Group, 2001. Retreived December 10, 2002 from http://www.yankeegroup.com/public/news_releases/news_r elease_detail.jsp?ID=PressReleases/news_09102002_wmec .htm [9] Palm OS. Retrieved December 22, 2002 from http://www.palmsource.com/palmos/ [10] Pocket PC. Retrieved November 25, 2002, from http://www.microsoft.com/mobile/pocketpc/ [11] S. Saha, M. Jamtgaard, and J. Villasenor. Bringing the wireless Internet to mobile devices. IEEE Computer, 34(6):54-58, 2001. [12] Symbian. Retrieved December 10, 2002 from http://www.symbian.com/ [13] U. Varshney, R. J. Vetter, and R. Kalakota. Mobile commerce: A new frontier. IEEE Computer, 33(10):32-38, 2000. [14] WAP: Wireless Application Protocol. Open Mobile Alliance. Retrieved November 21, 2002 from http://www.wapforum.org/ [15] The Yankee Group publishes U.S. mobile commerce forecast. Reuters, 2001. Retreived December 16, 2002 from http://about.reuters.com/newsreleases/art_31-10- 2001_id765.asp [16] R. Yavatkar and N. Bhagawat. Improving end-to-end performance of TCP over mobile internetworks. In Proceedings of the Workshop on Mobile Computing and Applications, Santa Cruz, California, 1994. Proceedings of the 23 rd International Conference on Distributed Computing Systems Workshops (ICDCSW’03) 0-7695-1921-0/03 $17.00 © 2003 IEEE