LITERATURE REVIEW
2.0 Introduction
In this chapter we review the wide-ranging and multi-disciplinary literature on SMS based student result dissemination system. This critical literature review highlights the strengths of the existingresearch on the processing system and exposes some important shortcomings. But first of all let’s look at the concept national identity its self.
2.1 Messaging System
What is SMS (Short Message Service)?
SMS stands for Short Message Service. It is a technology that enables the sending and receiving of messages between mobile phones. SMS first appeared in Europe in 1992. It was included in the GSM (Global System for Mobile Communications) standards right at the beginning. Later it was ported to wireless technologies like CDMA and TDMA.
The GSM and SMS standards were originally developed by ETSI. ETSI is the abbreviation for European Telecommunications Standards Institute. Now the 3GPP (Third Generation Partnership Project) is responsible for the development and maintenance of the GSM and SMS standards.
As suggested by the name "Short Message Service", the data that can be held by an SMS message is very limited. One SMS message can contain up to:
160 characters if 7-bit character encoding is used. (7-bit character encoding is suitable for encoding Latin characters like English alphabets.)
70 characters if 16-bit Unicode UCS2 character encoding is used. (SMS text messages containing non-Latin characters like Chinese characters should use 16-bit character encoding.)
SMS text messaging supports languages internationally. It works fine with all languages supported by Unicode, including Arabic, Chinese, Japanese and Korean.
The point-to-point SMS provides a mechanism for transmitting "short" messages to and from wireless handsets. The service makes use of a short message service center (SMSC) which acts as a store and forward system for short messages. The wireless network provides for the transport of short messages between the SMSCs and wireless handsets. In contrast to existing text message transmission services, such as alphanumeric paging, the service elements are designed to provide guaranteed delivery of text messages to the destination.
Initial applications of SMS focused on eliminating alphanumeric pagers by permitting two-way general purpose messaging and notification services, primarily for voice mail. As technology and networks matured, a variety of services were introduced, including electronic mail and fax integration, paging integration, interactive banking, and information services such as stock quotes. Wireless data applications include downloading of SIM cards for activation, debit, and profile editing purposes. It is possible to send ringtones, pictures, operator logos, wallpapers, animations, business cards (e.g. VCards) and WAP configurations to a mobile phone with SMS messages.
2.6.1 Benefits of Short Message Service
In today's competitive world, differentiation is a significant factor in the success of the service provider. Once the basic services, such as voice telephony, are deployed, SMS provides a powerful vehicle for service differentiation.
The benefits of SMS to the service provider are as follows:
Increased call completion on wireless and wireline networks by leveraging the notification capabilities of SMS
An alternative to alphanumeric paging services
Enabling wireless data access for corporate users
Provision of value-added services such as e-mail, voice mail, and fax mail integration, reminder service, stock and currency quotes, and airline schedules
Provision of key administrative services such as advice of charge, over-the-air downloading, and service provisioning
All of these benefits are attainable quickly with modest incremental cost.
The benefits of SMS to subscribers center on convenience, flexibility, and seamless integration of messaging services and data access. From this perspective, the benefit is to be able to use the handset as an extension of the computer. SMS also eliminates the need for separate devices for messaging since services can be integrated into a single wireless device — the mobile terminal.
2.6.2 SMS Network Elements and Architecture
The basic network structure of the SMS is depicted in fig 2.5
Fig 2.5 SMS network element and architecture
Short Messaging Entities: Short messaging entity (SME) is an entity which may receive or send short messages. The SME may be located in the fixed network, a mobile station, or another service center.
Short Message Service Center: Short message service center (SMSC) is responsible for the relaying and store-and forwarding of a short message between an SME and mobile station.
SMS-Gateway/Interworking Mobile Switching Center: The SMS gateway MSC (SMS-GMSC) is an MSC capable of receiving a short message from an SMSC, interrogating a home location register (HLR) for routing information, and delivering the short message to the "visited" MSC of the recipient mobile station.
The SMS interworking MSC (SMS-IWMSC) is an MSC capable of receiving a short message from the mobile network and submitting it to the appropriate SMSC.
Home Location Register: The home location register (HLR) is a database used for permanent storage and management of subscriptions and service profiles. Upon interrogation by the SMSC, the HLR provides the routing information for the indicated subscriber. The HLR also informs the SMSC, which has previously initiated unsuccessful short message delivery attempts to a specific mobile station, that the mobile station is now recognized by the mobile network to be accessible.
Mobile Switching Center: The mobile switching center (MSC) performs the switching functions of the system and controls calls to and from other telephone and data systems.
Visitor Location Register: The visitor location register (VLR) is a database that contains temporary information about subscribers. This information is needed by the MSC in order to service visiting subscribers.
The Base Station System: All radio-related functions are performed in the base station system (BSS). The BSS consists of base station controllers (BSCs) and the base transceiver stations (BTSs), and its primary responsibility is to transmit voice and data traffic between the mobile stations.
The Mobile Station: The mobile station (MS) is the wireless terminal capable of receiving and originating short messages as well as voice calls. The wireless network signaling infrastructure is based on Signaling System SMS makes use of the mobile application part (MAP) which defines the methods and mechanisms of communication in wireless networks, and uses the services of the transaction capabilities application part (TCAP). An SMS service layer makes use of the MAP signaling capabilities and enables the transfer of short messages between the peer entities.
2.2 Evaluation of similar systems
2.2.1 NTU eXpress SMS
NeXS (NTU eXpress SMS) is used at the Nanyang Technological University. To use NeXS the user needs to be an undergraduate student of NTU and needs to register his/her mobile phone on the NeXS Portal. NeXS accepts numbers from three mobile providers (Singtel/Starhub/M1). Once a mobile phone is registered, the student can use the phone to send SMS and access information. However, students can only use the mobile number that was registered.
To get exam results via NeXS, users send the keyword NTU RESULT to 74000. If the exam results of the current semester are released, NeXS will respond with the reply (Ling, 2005).
2.2.1.1 Strength of NeXS
The primary strength of NeXS is that it offers a form of security by ensuring that only the registered mobile phone can request the result. NeXS also provides other SMS services like examination seating arrangements, subject timetable, library account information, and NTU staff directory search.
2.2.1.2Weakness of NeXS
The fact that NeXS allows students to register their mobile phone number and limits access to the number is quite a disadvantage than an advantage. This is because it reduces the flexibility of the system and also poses a threat of identifying whether it is the real owner of the phone that is re- questing for the result. For example, a student can take another student’s phone and request for the student’s result. NeXS cannot tell that the request wasn’t made from the real owner of the phone. Also, if the register phone is stolen or lost, the student would have to visit the website to register a new phone. NeXS also provides examination result for the recently concluded semester.
2.2.2 SMS Result Checking of Board of Secondary Education, Orissa
The Board of Secondary Education in Orissa makes the HSC exam result available via SMS. The examination result is requested by sending the SMS Code: HSCR RollNo (for regular/regular Correspondence Courses) and HSCX Roll-No (for Ex-regular/Ex-regular Correspondence Courses) to 56505 (Desi, 2008).
2.2.2.1 Weakness of the System
The system allows requests from only BSNL Mobile and does not provide any form of security. Students can easily request the results of others by simply specifying their roll number.
2.2.3 MUET SMS Result Checking
The checking of MUET Result via SMS is also another example of SMS result checking. This system receives SMS in the format MUET <space> IC Number, sent to 39003. The service charges 15 cents for each message sent and 30 cents for each received.
2.2.3.1 Weakness of the System
The system does not offer any form of security. A student with the knowledge of another student’s IC number can request for that student’s result. It is also expensive on the side of the users.
In summary, none of these systems provide any practical form of security and are, therefore, susceptible to several security issues. Also, they provide only the current examination results and this prevents users from requesting for older results.
2.3 GSM PHONES
Global System for Mobile communications (GSM: originally from Groupe Spécial Mobile) is the most popular standard for mobile phones in the world. Its promoter, GSM differs from its predecessors in that both signaling and speech channels are digital call quality, and so is considered a second generation (2G) mobile phone system.
A mobile telephone or cellulartelephone (commonly, "mobile phone" or "cell phone") is a long-range, portable electronic device used for mobile communication. In addition to the standard voice function of a telephone, current mobile phones can support many additional services such as SMS for text messaging, email, packet switching for access to the Internet, and MMS for sending and receiving photos and video. Most current mobile phones connect to a cellular network of base stations, which is in turn interconnected to the public switched telephone network (PSTN). It is necessary to use a phone that is GSM AT compliant. Then, it is possible to communicate with the phone through AT commands.