SMS & MMS

Technologies

Key Concepts

The Digital Wireless Telephony

comprise of two main working

technologies:

GSM which stands for Global System

for Mobile Communication.

CDMA which stands for Code Division

Multiple Access.

GSM Technology

More than 690 mobile networks provide GSM services in more than 213 countries which means in total 82.4% people globally uses GSM mobile connections.

China being on the top followed by Russia, India & USA.

GSM is a “ time division” system, thus sometimes called as TDMA.

CDMA Technology

Both GSM and CDMA are multiple access

technologies.

CDMA employs spread-spectrum technology

and a special coding scheme (where each

transmitter is assigned a code).

Spread spectrum is a form of wireless

communications in which the frequency of the

transmitted signal is deliberately varied. This

results in a much greater bandwidth than the

signal would have if its frequency were not

varied.

Difference between the two

In CDMAs, there is one physical channel and a

special code for every device in the coverage

network. Using this code, the signal of the

device is multiplexed, and the same physical

channel is used to send the signal.

In GSMs, every cell has a corresponding

network tower, which serves the mobile

phones in that cellular area which in turn

makes GSMs more accessible as they work on

multiple frequency bands

(850/900/1800/1900MHz).

Network services in CDMAs are Handset-Specific

whereas in GSMs are SIM-Specific. User has option

to select handset of his choice.

Frequency-time comparison:

SMS, what is it ?

Short Message Service (SMS) is a text messaging

service component of phone, Web, or mobile

communication systems. It uses standardized

communication protocols to allow fixed-line or

mobile phone devices to exchange short text

messages.

Short message service is a mechanism of delivery

of short messages over the mobile networks. It is

a store and forward way of transmitting

messages to and from mobiles.

How Does It Works ?

The message (text only) from the sending mobile is stored in a

central short message center (SMC) which then forwards it to the

destination mobile. This means that in the case that the recipient is

not available, the short message is stored and can be sent later.

Each short message can be no longer than 160 characters. These

characters can be text (alphanumeric) or binary Non-Text Short

messages. An interesting feature of SMS is return receipts. This

means that the sender, if wishes, can get a small message notifying

if the short message was delivered to the intended recipient.

Since SMS used signaling channel as opposed to dedicated

channels, these messages can be sent/received simultaneously with

the voice/data/fax service over a GSM network.

SMS supports national and international roaming. This means that

you can send short messages to any other GSM mobile user around

the world. With the PCS networks based on all the three

technologies, GSM, CDMA and TDMA supporting SMS, SMS is more or

less a universal mobile data service.

SME - Short Message Entity

SMC – Short Message Center

GMSC – Gateway MSC

MSC – Message Switching Center

HLR – Home Location Register

VLR – Visitor Location Register

BSS – Base Station System

The SME (Short Message Entity) which can be located in the fixed

network or a mobile station, receives and sends short messages.

The SMC (Short Message Center) is the entity which does the job of

store and forward of messages to and from the mobile station.

The GWMS (SMS gateway MSC) is a gateway MSC that can also

receive short messages. The gateway MSC is a mobile network’s

point of contact with other networks. On receiving the short

message from the short message center, GMSC uses the SS7

network to interrogate the current position of the mobile station

form the HLR, the home location register.

HLR is the main database in a mobile network. It holds information

of the subscription profile of the mobile and also about the routing

information for the subscriber, i.e. the area (covered by a MSC)

where the mobile is currently situated. The GMSC is thus able to

pass on the message to the correct MSC.

MSC (Mobile Switching Center) is the entity in a GSM network

which does the job of switching connections between mobile

stations or between mobile stations and the fixed network.

A VLR (Visitor Location Register) corresponds to each MSC and

contains temporary information about the mobile, information

like mobile identification and the cell (or a group of cells) where

the mobile is currently situated.

Using information form the VLR the MSC is able to switch the

information (short message) to the corresponding BSS (Base

Station System), which transmits the short message to the

mobile.

The BSS consists of transceivers, which send and receive

information over the air interface, to and from the mobile

station.

This information is passed over the signaling

channels so the mobile can receive messages

even if a voice or data call is going on.

Advantages & Disadvantages

PROs :

1. You can send then any time – Day or Night.

2. Person you are sending it to do not have to have

their mobile phones switched on.

3. It can save time. Rather than interrupting them

with calls you can simply message them.

4. SMS are good for Informal messaging.

5. SMS is personal. It goes straight to the

recipient’s mobile phone. The message is

literally delivered directly into their hand.

CONs :

1. Messages are plain vanilla in nature. You can only send simple text messages. There is no scope for any graphics or audio.

2. The messages are limited by size. An SMS message can’t exceed 160 characters (70 Characters if Arabic, Chinese languages are used).

3. Could not be used for Formal Messaging.

4. SMS need Basic Typing Skills.

5. Delivery Failure - Unfortunately with bulk SMS marketing, service interruption occasionally occurs. Thus results in delivery failure. SMS is simply not as reliable as email yet, regardless of the provider.

Okay ! Now on to MMS

MMS Stands for Multimedia Messaging Service.

It is a communications technology developed by

3GPP (Third Generation Partnership Project)

that allows users to exchange multimedia

communications between capable mobile phones

and other devices.

To send or receive an MMS message, the phone

makes a GPRS connection (to a GPRS APN). It

then usually connects to the MMSC for

sending/receiving messages through a WAP

proxy/gateway.

An extension to the Short Message Service, MMS defines a

way to send and receive, almost instantaneously, wireless

messages that include images, audio, and video clips in

addition to text.

When the technology has been fully developed, it will

support the transmission of streaming video. A common

current application of MMS messaging is picture messaging

(the use of camera phones to take photos for immediate

delivery to a mobile recipient). Other possibilities include

animations and graphic presentations of stock quotes,

sports news, and weather reports.

There are two important standards that define MMS

technology, one published by the 3GPP (3GPP TS 23.140),

and the other a series of MMS specifications published by

the Open Mobile Alliance (OMA). These two standard

bodies cooperate to define the MMS protocols.

Protocols Defined

When MMS is discussed, We will often hear details of different MMS

related protocols, such as MM1, MM3, MM4, MM7.

MM1 is the protocol that is used between a mobile device and the

MMSC Messaging Server. It defines how mobile phones send and

receive messages through the MMSC.

MM3 is the protocol that is used between an MMSC and other

messaging systems. It is not so much a protocol, as much as a

definition of requirements for how an MMSC must be able to

interoperate with other messaging systems. In the real world, this

is primarily done via the SMTP e-mail protocol.

MM4 is the protocol that is used to interconnect MMSCs. It is an

SMTP-based protocol with additional headers defined.

MM7 is the protocol that is used to allow Value Added Service

Provider (VASP) applications to send and receive MMS messages via

an MMSC.

MMS is developed in two separate phases.

Based on General Packet Radio Services (GPRS),

the currently available MMS is similar to a brief

PowerPoint presentation.

The second phase of MMS will require a 3G network

to enable streaming video.

How does it works ?

The sending phone initiates a data connection that provides TCP/IP network connectivity, usually over GPRS.

The sending phone performs an HTTP POST to an MMSC of the MMS message encoding in the MMS Encapsulation Format, as defined by the Open Mobile Alliance. The encoded MMS message includes all of the content of the MMS message, as well as header information, including a list of intended recipients for the message.

The MMSC receives the MMS message submission and validates the message sender.

The MMSC stores the content of the MMS message and makes it available as a dynamically generated URL link.

The MMSC generates an MMS notification message, which is sent via WAP Push over SMS to the message recipient(s). This MMS notification message contains a URL pointer to the dynamically generated MMS content.

The recipient receives the MMS notification message. It then initiates a data connection that provides TCP/IP network connectivity (usually over GPRS).

The recipient phone performs an HTTP get to retrieve the MMS message content URL from the MMSC.

Advantages & Disadvantages

PROs :

1. whereas MMS supports images, videos and audio in your

message. MMS messages can include photos and videos

recorded on your phone or media added to your phone

from your computer. On some phones you can use

emoticons via MMS. This higher level of personalization

allows you to deliver voice messages and add more context

to your message than using text alone.

2. SMS messaging limits your messages to 160 characters --

including spaces and punctuation. MMS messaging not only

allows you to embed more styles and format your text, but

also allows significantly longer messages between phones.

There is not a set character limit for MMS, though your

phone may apply one.

CONs :1. MMS created by one brand phone may not be compatible

with another brand of phone’s capabilities.

2. Some phones may be configured poorly leading to the

failure of MMS delivery.

3. Because of the large amount of transferring of MMS to

different networks, sending to a large group of customers

can be slow.

HAPPY LEARNING !

Arun Shuklaarun.shukla2694@gmail.com

Thank you All