The Study Of Short Message Service Computer Science Essay

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Short Message Service for short is also known as SMS. The Short Message Service is the in style data service amongst cellphone users in this day and age. Initially the SMS is devised as a paging mechanism designed for voice mails for GSM specification in 1992; subsequently SMS has advanced into one of the most successful wireless data services. Its focal intention is to provide communication protocols that let the sender and receiver to send and receive messages.

The data that of an SMS message is very limited, one SMS message is restrained to approximately up to 140 bytes of data that is the main disadvantage of SMS. An expansion called concatenated SMS (Long SMS) was developed to overcome this problem. It enables a message to hold more than 160 English characters. However due to its unpopularity of this technology, it is less commonly supported compared to SMS on wireless devices.

The study of Short Message Service is complex due to several rationales and one of them is the cost factor. For the reason that SMS messages are delivered through infrastructure managed by an operator and is outside the power of the researchers whom are perform the vulnerability analysis. Since mobile phone operators are capable of filtering and modifying short messages during delivery, there is the ambiguity of whether a message is delivered to the target in its original form. There is likelihood that the operators do not filter messages intentionally but by using equipment that are unable to handle some messages. Furthermore, SMS is an undependable service, as messages be capable of being delayed or discarded for no reason making the research prolonged.

Herein study, the Corner Screen Cinema System (CSC) will utilize this service for advertising means by sending text messages to hand phones. The Corner Cinema System offers an entire ticketing and concessions system allowing cinemas to expand their business management system, providing an alternate method to grip customers. Allowing customers the accessibility and convenience to access news or promotion that the cinema currently offers form the convenience of their own home or wherever they are. Executing SMS system is the fastest and most efficient way to relate to customer directly without customers being physically present.

Aims of Research

The purpose of this study is to implement SMS technology into the CSC System. There are a few potential of sending out SMS to users, either through mobile phone or the internet from a computer. So in order to achieve the aim of this research, the following objectives need to be fulfilled:

To categorize the SMS processes and the stages of report

To understand the usage of GSM Modem

To identify the SMS gateways

To identify the architecture used.

To determine the advantages by comparing various technology

To implement SMS technology

Chapter 2: SMS Basic Features

A study was carried out in relation to the fundamental theory of SMS technology. SMS consists of several essential features which comprises of messaging status report, message submission reports, message delivery reports, validity period of an SMS messages. These are the results of the research in the following sections.

2.1 Short Message Entity (SME)

Short Message Entity (SME) is an element that can send or receive short messages. SME can either be a software application in a mobile handset or hardware like fax equipment or even a remote Internet Server, etc. To use SME in a mobile phone, a proper configuration is needed in order to operate properly in a mobile network.

SME can also be a server by connecting to the SMS center straight forward or through a gateway. This kind of SME is also known as External SME (ESME). Usually an ESME can be a WAP proxy/server, email gateway, or even a voice mail server. In the process of exchanging between short messages, a sender is normally known as originator SME whereas the receiver is known as recipient SME.

2.2 Message Status Report

From the report, there is a way to know whether an SMS message has reached the recipient mobile phone successfully. In order to get this information, a standard procedure had been carried out, that is to send an acknowledgement flag in the SMS message to notify the SMS center for a status report about the delivery of this SMS message.

Figure 1: Status Report process

2.3 Message Submission Reports

Based on the research, after an SMS has been sent out from the phone and reach the SMS center. The SMS center will send an acknowledgement message report to the mobile phone to inform whether the SMS contain any errors or failures. If there is no error, the SMS center sends back a positive submission report to the mobile phone. Else a negative submission report will send back to the mobile phone.

After a period of time if the mobile phone did not receive any of the submission report, it can concludes that the message report has been lost. The mobile phone may then re-send the SMS message to the SMS center. An acknowledgement flag will be set in the new SMS message to inform the SMS center that this SMS message has been sent before. If the previous message submission was successful, the SMS center will ignore the new message but send back a message submission report to the phone.

Figure 2: Submission report process

2.4 Message Delivery Reports

A message delivery report will be sent back to the SMS center after receiving an SMS message to inform whether there are any errors in the message. A mobile user will not know that this process is happening. If the sender requested a status report earlier, the SMS center sends a status report to the sender when it receives the message delivery report from the recipient. If the SMS center does not receive the message delivery report after a period of time, it concludes that the message delivery report has been lost. The SMS center then re-sends the SMS message to the recipient.

2.5 Validity Period of an SMS message

To start with, if the recipient mobile phone is offline an SMS message is stored temporarily in the SMS center. After the message is stored inside the SMS center database, there will be some sort of a countdown timer that specify the period of time before the message is deleted so that the SMS message will not be forwarded to the recipient mobile phone when it becomes online. This period is called the validity period.

2.6 Summary

Throughout the research from the chapter, a few features or processes have been identified. The features are, SME, message status report, message submission report, message delivery report and last of it is its validity period. Based on these message notifications mentioned above, it is concluded that without these notifications the result of a sent message would not be acknowledged whether the message is successfully sent out or there are some interference that interfere with the message. It is important to know about the status of a message, that's why it is important to study the above features.

Chapter 3: Cellphone and GSM / GPRS as Wireless Modem

The research about this chapter is about which hardware to use as it will act as a wireless modem between the software and hardware. Three possible hardware had been identified to have the potential of being a wireless modem. First is a cell phone, second is GSM modem, and finally a GPRS modem. All of the above have the potential of being a wireless modem. The features and pros and cons will be discussed in this chapter.

3.1 Cell Phone

A cell phone as we all know is able to make calls and send messages, but some people use it as a wireless modem as well. A wireless modem is almost same with the dial-up modem. The only difference is that a wireless modem dispatch its data through a wireless network while the dial-up modem dispatch its data by using a copper telephone line. Wireless modem nowadays is able to be replaced by a mobile phone. However there are some limitations regarding mobile phone as a wireless modem which will be discussed later.

Here is the method used on how a cell phone can act as a wireless modem. To start with, connection has to be established before sending a message. One have to connect the phone to the computer by plugging in the phone through USB cable with the computer and on a program called Hyper Terminal. After that just enter "AT" in the program to carry out the test. Let's say if the phone have received "AT" then it will reply back with "OK" to indicate that the connection establishment is successful. The next step to do after testing the connection between computer and the cell phone is to check whether the cell phone supports AT command either to send, receive or send messages.

Using a cell phone as a wireless modem has its drawback also, that is its sending rate of messages is very low. It can only send out 6-10 messages at a time (1minute). This low rate performance is have nothing to do with the phone acting as a modem, it doesn't matter whether what connection type it is using either connecting using serial cable, USB cable, Bluetooth or infrared. The main factor is because of the wireless network that only supports these numbers of sending rate.

3.2 GSM Modem

Figure 3: GSM modem

GSM modem is a wireless modem that functions with a GSM wireless network. A wireless modem similar to the dial-up modem. The main difference between these two devices is that a dial-up modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves.

A GSM modem is capable of being an external device or a PC Card/PCMCIA Card. More often than not, an external GSM modem is connected to a computer by the use of serial cable or USB cable. Akin to a GSM mobile phone, a GSM modem necessitates a SIM card from a wireless carrier for it to function. GSM modem has the velocity and capability in dealing with SMS; thus users do not need to subscribe to an SMS service provider. The GSM modem charges directly through the SIM card inserted in the modem, regardless of the service provider the SIM card is it will charge through it directly and it won't be cheap. Throughout the worlds, GSM modems is an economical solution for sending SMS messages from a computer, as the sender is paying the message(s) from the SIM card provider.

A result stated that by using Hyper Terminal (Start > Programs > Accessories > Communications> Hyper Terminal) software to send SMS from a PC are like the followings:

Figure 4: Example of a Hyper Terminal Result

Referring to the above figure, the normal command set used are Hayes Modem command sets. An AT command that is sent to the modem from a computer. Followed by the GSM modem reply saying 'OK' meaning the modem is prepared to receive instructions. Followed by a request AT+CMGS="9810080856" where by the message is to send to a phone with MSISDN of 9810080856. Later the GSM modem will respond with a '>' sign.

3.3 GPRS Modem

Figure 5: GPRS Modem

***A GPRS modem is a GSM modem that in addition sustains the GPRS technology intended for data transmission. GPRS is a short form for General Packet Radio Service, a development of GSM in which it is a packet-switch technology. A benefit of GPRS over GSM is that GPRS has a greater data transmission rate.

3.4 Comparison between cell phone and GSM/GPRS Modems

From the research, a GSM modem is basically a wireless modem that internally works with GSM networks. Technically, wireless modem behaves like a Hayes compatible dial-up modem (A modem that recognizes the Hayes command set).

Just like the mobile phone, GSM modem requires a SIM card from a wireless carrier so that it can operate. A PC uses AT command set to control a modem, so therefore a GSM modem can support a command set of AT commands.

On the other hand, a GPRS (General Racket Radio Service) modem is actually a GSM modem with additional support for GPRS technology for data transmission. A research had been carried out by collecting information from the World Wide Web about this modem. Throughout the research, a GPRS modem is actually based on a packet-switched technology, as an extension to GSM.

The collected information from the research says that the GPRS modem is better than GSM modem because a GPRS modem has a much higher data transmission speed. Other than that, a GPRS modem can be used as the bearer of SMS. According to the information obtained, if using GPRS to send SMS, a record of 30 SMS messages per minute may be achieved. Comparing with GSM, this is much faster where it can only support the rate of 6-10 messages per sending. Now looking at the downside of GPRS, it require a GPRS modem to be able to send and receive SMS but some wireless carriers do not support the sending and receiving of SMS through GPRS. GPRS modem is normally used for sending and receiving of MMS.

This topic is created to find out which is the best hardware to use as a modem. From the research result, it has been said that the GSM/GPRS modem is the highly valuable hardware recommended by people for sending and receiving messages. So why is it people prefer GSM/GPRS modem than the cell phones? If compared with GSM/GPRS modems there are some certain limitations with cell phones. Examples of the drawbacks are the cell phones that do not support concatenated SMS messages when using with a computer. A normal SMS message can contain only 140 bytes but if a message is over that limited amount it is known as concatenated message. Out in the real world if a sender sends a concatenated message, the phone will then divide the message into a few parts before sending out to the receiver; and if the receiver received concatenated messages, the phone will automatically combine these messages together so that it is readable. In this case, it won't work on the computer. If the phone receives a concatenated message it will forward it directly to the computer without combining them together.

Beside that, not all phone support AT commands which is important for the communication. It is a command that is used to communicate with the phone and computer, it is sort of like a communication language between them.

3.5 Summary

Cell phone is the selection choice out of the 3 devices because by using a phone itself only is cheap comparing to the GSM/GPRS modem. Using a phone as a modem is cost effective, the cost for a single GSM modem is around RM300-RM1000 and higher. Although a cell phone's price can be higher than that, but a phone is a daily necessity for us so it will not be a waste if a phone is used. If the other way round, a GSM modem can only used as a wireless carrier and it requires a SIM card to work. After this project, there is a low chance that the GSM modem will be used again.

Chapter 4: SMS Gateway

4.1 Introduction

A way of sending a text message with or without using a mobile phone is by using a SMS gateway. In a more specific way, it is a device or service that offers SMS transit that transform messages to mobile network traffic from other media allowing transmission or receipt of SMS messages with or without using the mobile phone. This chapter will discuss about SMS gateway and what SMS gateway had been identified.

4.2 SMS Gateway

***One dilemma of SMS messaging is that SMSCs (SMS Centers) developed by different companies use their own communication protocol and most of these protocols are proprietary. For example, Nokia has an SMSC protocol called CIMD whereas another SMSC vendor, CMG, has an SMSC protocol called EMI. Two SMSCs cannot be connected if they do not support a common SMSC protocol. There is a solution to this problem, an SMS gateway is placed between two SMSCs. This is emphasized in the figure below. The SMS gateway acts as a relay between the two SMSCs. It translates one SMSC protocol to another one. By using SMS gateway, two different wireless carriers to interconnect their SMSCs for purposes such as enabling the exchange of inter-operator SMS messages.

Figure 6: Two SMS Centers connects to an SMS Gateway

***SMS gateway is helpful in a sense that it helps content providers and SMS application developer to decrease the application's complexity and development time. For example, in order to send and receive SMS messages on the server, the application need to connect to the SMS centers of the wireless carriers. An SMS messaging application may have to support various SMSC-specific protocols because various types of wireless carriers may use SMS Center from different vendors.

Figure 7: SMS messaging application connects to various types of SMSC without an SMS gateway

The solution for the above problem is to set up an SMS gateway to handle the above connections to the SMSC. Now that all the complexity of connecting too many SMSCs have been reduced by connecting the application to an SMS gateway. In order to support more SMSC, technician only needs to adjust the setting of the SMS gateway without changing the source code of the messaging application.

Figure 8: SMS messaging application connects to various types of SMSC with an SMS gateway

4.3 Free SMS Gateway Software

SMS software is nothing without an SMS gateway, so SMS gateway carries a big responsibility in SMS messaging. So an SMS gateway software sometimes can be very expensive and costly. Therefore, in search of a free SMS gateway is not an easy task. Luckily there is a free SMS gateway software packages can be downloaded from the internet. That open source software is called "Kannel" where it is written in C language. Its function is to handle connection establishment to SMSC, cell phones, and GSM/GPRS modems.

4.4 Comparing two of the implementations:

This part of the SMS gateway chapter will discuss about the comparison about two implementations which is "Direct to Mobile Gateway" and "Direct to SMSC Gateway". Two of these had been identified as worthy implementation in this research. "Direct to Mobile Gateway" means connecting to a local mobile network through a SIM card. While "Direct to SMSC Gateway" means connecting directly to a mobile operator's SMSC either through the internet or direct leased line connections.

4.4.1 Direct To Mobile Gateway

SMS messages can either be sent or received by email, from web pages or other software application via an appliance Direct to Mobile Gateway. This appliance differs from SMS Aggregators as they are installed on a network along with connection to a local mobile network. To use this appliance one has to register for a Subscriber Identity Module (SIM) through the mobile operator as well as installing this gateway before being able to connect to the mobile network. Direct To Mobile Gateway appliance targets consumers whom use low to medium capacity messaging.

4.4.2 Direct To SMSC Gateway

SMS text messages can either be sent or received by email, from web pages or other software application via an appliance Direct To SMSC Gateway. This Gateway connects to a Mobile Operator's SMAC over the internet or direct leased line connection; altering the message format into a format recognized by the SMSC, known as SMPP protocol. Direct To SMSC Gateway is exercised by SMS Aggregators providing SMS services to their consumers, this application is directed towards customers whom utilize high capacity messaging. In order to utilize this facility consumers have to sign a contract with the Mobile Operator.

4.5 Summary

From the above discussion, we can conclude that one can either connect using "Direct to Mobile Gateway" or "Direct to SMSC Gateway" method. The method chosen is "Direct To Mobile Gateway" because it is using a cell phone or GSM modem to connect so it reflect to the connection method using cell phone as a wireless modem. Other than that, it is connected to a computer which can send or receive messages.

Chapter 5: SMS Architecture


Efficient network technologies are needed in order to lower costs while increasing the volume. To further realize the benefits of the new architecture, a research to compare between the traditional SMS architecture and new SMS architecture is being carried out.

5.1 Traditional SMS architecture

Figure 9: Traditional SMS Architecture

***Figure above shows that the traditional SMS architecture store every message and forward the message to its destination using a Short Message Service Center (SMSC). A gateway is the included in the SMSC to all the content store on the network.

***From the rapid growth of subscribers every year, an addition of at least one new SMSC every year is requires. Even though the cost of the infrastructure if significantly high, the pay back from each deployment is high enough to cover its construction and operating cost in less than a couple of weeks. With the advance high-peak-volume application such as mass voting that is required by television shows, thus dramatically increase the mobile operator costs. Therefore a new cost-effective architecture is needed now and then to meet the demands of high-peak application at a reduced cost.

5.2 New Architecture

Figure 10: SMS architecture with Router

***According to the figure above, the new architecture introduced a new concept that requires router. With the help of a router, it helps to eliminate the trouble of storing and delivering each message immediately if the recipient is available. As time goes by, there are an increase in the number of subscribers that kept their phones switched on at all times resulting in the delivery became progressively more feasible with the result that increasing amounts of "store and forward" could be avoided thus reducing costs.

***The subscribers that kept their mobile phone on 24/7 also tend to be eager users of new high-peak, high-volume applications that allows SMS routers becoming the facilitators for new applications and features that do not require storage but need fast and responsive signaling such as football score alerts, voting and SPAM filtering. For the above to run smoothly, router is the main cause to success. Result of the research shows that because of router, the cost drop significantly at the same time enables thousands more attempts per second to satisfy increasing volume requirements.

***In order to compete with vendors to attract new architecture, the developers of traditional SMS architecture equipment have changed their configurations so that the architecture can perform direct delivery as well as SMS filtering which has resulted in lower platform costs. Both old and new solution providers competing to come out with newer solution which has helped mobile operators keep their costs down and the final people who come out with all the benefits are subscribers.

5.3 Summary

In order to implement SMS technology into the project, understanding its architecture is equally important. An SMS architecture plays a great role in delivering a high-performance solution. In short, the architecture must be flexible in order to adapt to the changing and evolving world of technology. A dependable work allocation mechanism is important, and that mechanism must be flexible enough to change size and shape as required to meet the unstable configurations. A developer have to know how architecture and application work together in order to deliver the vital performance.

Chapter 6: SMS and Other Services

This chapter is about why SMS is chosen out of so many services. Comparison with various services helps to identify advantages in implementing SMS rather other services. This chapter is about comparing "SMS and MMS", "SMS and EMS", and "SMS and Email"


6.1 SMS and MMS

After the mobile companies had invented calls to be made from phone, it then offered another service called SMS or short message services. SMS capability is restricted to sending text-only messages from a mobile phone to another phone via the service provider's special service offered for SMS. In order for user to use SMS, the phone using SMS has to support the function and the service provider offers a plan for this. A single SMS can contain up to 160 characters while longer messages may be separated into several part of messages.

While MMS or known as Multimedia Messaging Service on the other hand can include not only text but pictures and short videos as well therefore it is more advanced and enhanced than the SMS service. Same as SMS service, MMS also requires a service or plan from the service provider and the sender and receiver phone must also support this function.

So why use SMS instead of MMS? The reason is because SMS will be accepted on 100% of phones nowadays while MMS only about 80% or less of phones will accept MMS. For example iPhone 3G do not accept MMS, and most of the blackberries on Verizon and also other carriers have disabled MMS function the reason they think MMS is useless is because a blackberry or iPhone can receive email so it doesn't really need the use of MMS as an email already covers all or more function than the MMS. An operator is not needed in order to directly transmit messages to each other by using SMS function. Other than SMS convenient, SMS is also a cheaper way compared to MMS which have data transfer charges associated. MMS is much more expensive compared to SMS which is cheaper due to the taxing on the service. MMS will work most of the time but SMS works great with some factors to consider, sending SMS is for quick sending mode, important and short messages.

Besides, SMS only requires basic texting capability and nothing else so it is more specialized as it is only focus in the characters only. SMS is convenient because it stores and forwards a message if the end user is not available or the mobile phone is switched off or it is out of service area, the service will then resend the message that is stored in the storage to the receiver. On the other hand, MMS requires video uploading, saving and probably capturing function through an camera in the phone or images that are in the phone memory while SMS only require basic texting capability. That's why SMS is chosen in this project.

6.2 SMS and EMS

SMS is Short Message Service that uses mobile phone as a communication device and a text message as data transmitted over the service. EMS is Enhanced Message Service which is the enhanced version of the SMS. SMS as we all know are able to send message that contains up to 160 characters to another device and it can only store text or a collection of alphabets only. While for EMS, SMS only transmit characters only but EMS is able to provide service to transmit not only text but pictures and audios too.

EMS on the other hand also has their limit, it has limited picture and animation supports which means that if an EMS message is sent to a phone that does not support an EMS function, it will only display the EMS message as a standard SMS message. Obviously the SMS has the better of EMS here.

In conclusion, SMS has the better of EMS because SMS is widely supported by any kind of phone out there in the market. In addition, EMS is not an ideal choice for the project because the system does not need to send pictures, a normal text messages will do in order to spread some promotion news.

6.3 Comparison between SMS and Email

Email stands for Electronic Mail in short it is also called email, its function is to transmit an electronic email through the World Wide Web or the internet. Basically, email is created for end user to send a message directly from one computer to another computer. This require both computer to be connected to a LAN or WAN at the same time. An email infrastructure is that it store and forward a message whereby the email server will accept, forward, deliver and store messages. Email works well in hand-held computer as well example like mobile phones, iPhone, iPad and so on. Blackberry recently come out with a messaging function called the push email.

A push email allows a user to enter an unlimited amount of characters or words that a person can possibly put in a single email message compare to the traditional SMS message with a limited amount of 160 characters per message only. But it also comes with some short comings, one of the problem is that in order to use the push email function the receiver of the email must also have a specialized device that contain this function or a third party software solution.

Without this function, the whole plan won't work plus it is more costly because user will have to have a data plan just to use and the cost to have a fancy phone. SMS have been chosen in this project is because long message and picture is not needed in the message, a few sentences of text will do to promote the upcoming promotion. Although SMS will also have some charges but a lot of people are embracing it because of its accessibility, cheaper because a normal phone will do. SMS is easy to use as it does not need extra information to login to an account, by using a phone number an user can send out SMS messages instantly without any difficulties.

Chapter 3: Conclusion

Achievement of Objectives

To categorize the SMS processes and the stages of report

The SMS category with the distinctive features had been sorted out in chapter 2.1.

To understand the usage of GSM Modem

In chapter 2.2, the different type of possible hardware to use had been identified.

To identify the SMS gateways

Few approaches of sending out an SMS messages with or without hand phone had been identified in chapter 2.3.

To identify the architecture used

There are a couple of unique architecture used in order for the SMS to work which were discussed in chapter 2.4, Traditional SMS architecture and SMS architecture

To determine the advantages by comparing various technology

In chapter 2.5 until 2.7, several technologies had been compared with the usage of SMS technology. The result came out positively towards the SMS technology side.

3.2 Research Conclusion

Research has been carried out to complete this seminar report, studying about the concept, architecture and network as well as on the aspect of the service such as characteristic of messages, sending and the arrival process. There are certain problems experienced with getting pure SMS interconnection or access to mobile network encountered during testing. An examination to connect the GSM modem to the computer in order to send message(s) to mobile phone has been carried out, it is a success regarding the above communication method. An action has been carried out to group the recipient whether sending to one person or a group of person and it works.

As part of the ongoing work, whether to be able systematically assess the reliability of SMS system is still as part of the plan. It is becoming particularly important nowadays to have a reliable SMS services as it has becoming a mission-critical applications such as emergency alerts and notifications for natural disasters. For us, its only for business purpose such as to notify members about promotions or events.