Research Into Short Message Service Computer Science Essay

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First of all, SMS stands for Short Message Service. The Short Message Service is arguably the most popular data service over cellular networks nowadays. Although it was originally conceived as a paging mechanism for voice mails as part of the GSM specification in 1992, since then SMS has evolved into one of the most successful wireless data services. Its main purpose is to serve communication protocols that allow the sender and receiver to send and receive messages.

As mentioned "Short Message Service", the data that can be held by an SMS message is very limited. One SMS message can contain approximately up to 140 bytes of data. This is one of the major drawback of SMS technology. To overcome this drawback, an extension called concatenated SMS (Long SMS) was developed. It can contain more than 160 English characters. But there is one drawback of this technology, is that it is less widely supported than SMS on wireless devices.

The research of Short Message Service is difficult for several reasons beside cost factor. The reason is because SMS messages are delivered through infrastructure controlled by an operator and thus is outside the control of the researchers who are conducting the vulnerability analysis. Another reason is the uncertainty of whether a message is delivered to the target in its original form. This is because mobile phone operators have the ability to filter and modify short messages during delivery. Also, it is also possible that the operator might not filter messages on purpose but might use equipment that cannot handle certain messages. Moreover, SMS is an unreliable service, meaning that the messages can be delayed or discarded for no certain reason. This makes the research very time-consuming.

In this research, the Corner Screen Cinema System (CSC) is going to make use of this service to serve the advertising purpose by sending text messages to hand phones is The Corner System Cinema. The Corner Cinema System provides a complete ticketing and concessions system that allows the cinema to have a better business management system, a better way to handle the customers. In order to let the customer know more about the news or promotion that the cinema offers, implementing the SMS method is the best way to interact with the customer directly without the need of dropping by at the cinema to find out.

Aims of Research

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

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 research has been carried out about the basic concept of SMS technology. SMS consists of a number of basic features which includes message 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.

2.1 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: Message Status Report

2. 2 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.

2.1.3 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.

2.1.4 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.

2.2 GSM / GPRS Wireless Modems

2.2.1 GSM Modem

What is a GSM Modem? A GSM modem is a wireless modem that functions with a GSM wireless network. A wireless modem acts like a 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 can be an external device or a PC Card/PCMCIA Card. Usually, an external GSM modem is connected to a computer via serial cable or USB cable. Like a GSM mobile phone, a GSM modem requires a SIM card from a wireless carrier in order to operate. GSM modem has the pace and efficient in term of dealing with SMS, it is because of it do not need to subscribe to an SMS service provider. The GSM modem take charges directly through the SIM card inserted in the modem, whatever service provider the SIM card is it will charge through it directly and it won't be cheap. In most part of the worlds, GSM modems are a cost effective solution for sending SMS messages through a computer, because the sender is paying the message(s) directly 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:

From the above, the standard command set used are Hayes Modem command sets. An AT command was sent to the modem from a computer. Then the GSM modem reply by saying 'OK' which means the modem is ready to take any instructions. Followed by a request AT+CMGS="9810080856" where by the message is to send to a phone with MSISDN of 9810080856. After that the GSM modem will respond with a '>' sign.

2.2.2 GPRS Modem

What is a GPRS Modem? A GPRS modem is a GSM modem that additionally supports the GPRS technology for data transmission. GPRS stands for General Packet Radio Service. An extension of GSM in which it is a packet-switch technology. An advantage of GPRS over GSM is that GPRS has a higher data transmission speed.

2.2.3 Comparison between 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). The main difference between a Hayes modem and a GSM modem is that the Hayes modem sends and receives data through telephone line while a GSM modem sends and receives data through radio waves.

From the technical view, GSM modem can be an external unit or a PCMCIA card. An external GSM modem is connected to a PC through a serial cable, a USB cable, Bluetooth or Infrared. Just like the GSM 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. 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.

In general, a GSM / GPRS modem is recommended for use with a computer to send and receive messages. This is because some mobile phones have certain limitations comparing to GSM / GPRS modems. The limitations are as below:

Some mobile phone models cannot be used with a computer to receive concatenated SMS messages.

Some mobile phone may not support some AT commands.

SMS messaging applications have to be available 24 hours a day.

Other than the above issues, mobile phones and GSM / GPRS modems are more or less the same for sending and receiving SMS messages from a computer.

2.3 SMS gateway

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.

One dilemma of SMS messaging is that SMSCs 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.

2.3.1 Comparing two of the implementations: Direct To Mobile Gateway Appliance

Sms text 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. 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.

2.4 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.

2.4.1 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 chitecture is needed now and then to meet the demands of high-peak application at a reduced cost.

2.4.2 New Architecture

Figure: 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.

2.5 Comparison between 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 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 just like what I am going to implement in the project.

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.

2.6 Comparison between 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.

2.7 Comparison between SMS and Email

Email stands for Electronic Mail in short we only called it 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 is 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.