Multimedia Messaging Service

MMS was originally developed within the Third-Generation Partnership Program (3GPP), a standards organization focused on standards for the UMTS/GSM networks.

Since then, MMS has been deployed world-wide and across both GSM/GPRS and CDMA networks.

MMS has also been standardized within the Third-Generation Partnership Program 2 (3GPP2), a standards organization focused on specifications for CDMA2000 networks.

As with most 3GPP standards, the MMS standards have three stages:

* Stage 1 - Requirements (3GPP TS 22.140) * Stage 2 - System Functions (3GPP TS 23.140) * Stage 3 - Technical Realizations

Both 3GPP and 3GPP2 have delegated the development of the Stage 3 Technical Realizations to the OMA, a standards organization focused on specifications for the mobile wireless networks.

MMS-enabled mobile phones enable subscribers to compose and send messages with one or more multimedia parts. Multimedia parts may include text, images, audio and video. These content types should conform to the MMS Standards. For example your phone can send an MPEG-4 video in AVI format, but the other party who is receiving the MMS may not be able to interpret it. To avoid this, all mobiles should follow the standards defined by OMA. Mobile phones with built-in or attached cameras, or with built-in MP3 players are very likely to also have an MMS messaging client—a software program that interacts with the mobile subscriber to compose, address, send, receive, and view MMS messages.

Wireless Access Point

One IEEE 802.11 WAP can typically communicate with 30 client systems located within a radius of 100 m. However, the actual range of communication can vary significantly, depending on such variables as indoor or outdoor placement, height above ground, nearby obstructions, other electronic devices that might actively interfere with the signal by broadcasting on the same frequency, type of antenna, the current weather, operating radio frequency, and the power output of devices. Network designers can extend the range of WAPs through the use of repeaters and reflectors, which can bounce or amplify radio signals that ordinarily would go un-received. In experimental conditions, wireless networking has operated over distances of several kilometers.

Most jurisdictions have only a limited number of frequencies legally available for use by wireless networks. Usually, adjacent WAPs will use different frequencies to communicate with their clients in order to avoid interference between the two nearby systems. But wireless devices can "listen" for data traffic on other frequencies, and can rapidly switch from one frequency to another to achieve better reception on a different WAP. However, the limited number of frequencies becomes problematic in crowded downtown areas with tall buildings housing multiple WAPs, when overlap causes interference.

Wireless networking lags behind wired networking in terms of increasing bandwidth and throughput. While (as of 2004) typical wireless devices for the consumer market can reach speeds of 11 Mbit/s (megabits per second) (IEEE 802.11b) or 54 Mbit/s (IEEE 802.11a, IEEE 802.11g), wired hardware of similar cost reaches 1000 Mbit/s (Gigabit Ethernet). One impediment to increasing the speed of wireless communications comes from Wi-Fi's use of a shared communications medium, so a WAP is only able to use somewhat less than half the actual over-the-air rate for data throughput. Thus a typical 54 MBit/s wireless connection actually carries TCP/IP data at 20 to 25 Mbit/s. Users of legacy wired networks expect the faster speeds, and people using wireless connections keenly want to see the wireless networks catch up.

As of 2006 a new standard for wireless, 802.11n is awaiting final certification from IEEE. This new standard operates at speeds up to 540 Mbit/s and at longer distances (~50 m) than 802.11g. Use of legacy wired networks (especially in consumer applications) is expected to decline sharply as the common 100 Mbit/s speed is surpassed and users no longer need to worry about running wires to attain high bandwidth.

Interference can commonly cause problems with wireless networking reception, as many devices operate using the 2.4 GHz ISM band. A nearby wireless phone or anything with greater transmission power within close proximity can markedly reduce the perceived signal strength of a wireless access point. Microwave ovens are also known to interfere with wireless networks.

GGSN - Gateway GPRS Support Node

A gateway GPRS support node (GGSN) acts as an interface between the GPRS backbone network and the external packet data networks (radio network and the IP network). It converts the GPRS packets coming from the SGSN into the appropriate packet data protocol (PDP) format (e.g. IP or X.25) and sends them out on the corresponding packet data network. In the other direction, PDP addresses of incoming data packets are converted to the GSM address of the destination user. The readdressed packets are sent to the responsible SGSN. For this purpose, the GGSN stores the current SGSN address of the user and his or her profile in its location register. The GGSN is responsible for IP address assignment and is the default router for the connected UE (User Equipment).The GGSN also performs authentication and charging functions

SGSN - Serving GPRS Support Node

A Serving GPRS Support Node (SGSN) is responsible for the delivery of data packets from and to the mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility management (attach/detach and location management), logical link management, and authentication and charging functions. The location register of the SGSN stores location information (e.g., current cell, current VLR) and user profiles (e.g., IMSI, address(es) used in the packet data network) of all GPRS users registered with this SGSN.

Common SGSN Functions

• Detunnel GTP packets from the GGSN (downlink)
• Tunnel IP packets toward the GGSN (uplink)
• Carry out mobility management as Standby mode mobile moves from Routing Area to Routing Area.
• Billing user data

GPRS Wireless Solutions

General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. The maturity of the GPRS system has made it suitable for use as a transport medium for remote monitoring of utility assets such as pipelines, dams, pumping stations and where network flow and pressure measurement is required across a wide area (e.g. district or nationally).



GPRS is different from the older GSM Circuit Switched Data (or CSD) connections that have been popular in the last few years. In CSD, a data connection establishes a circuit, and reserves the full bandwidth of that circuit during the lifetime of the connection. GPRS is packet-switched which means that multiple users share the same transmission channel, only transmitting when they have data to send. This means that the total available bandwidth can be immediately dedicated to those users who are actually sending at any given moment, providing higher utilisation where users only send or receive data intermittently. Web browsing, receiving e-mails as they arrive and instant messaging are examples of uses that require intermittent data transfers, which benefit from sharing the available bandwidth. Point to multi-point remote monitoring systems found in water utility systems also suit this, where historical data can be logged and retrieved periodically (e.g. every hour) for analysis. With suitable event messaging critical alarms and conditions can be sent between the regular datalog retrievals.

GPRS Tunnelling Protocol (GTP)

is the defining IP protocol of the GPRS core network. Primarily it is the protocol which allows end users of a GSM or WCDMA network to move from place to place whilst continuing to connect to the internet as if from one location at the Gateway GPRS Support Node (GGSN). It does this by carrying the subscriber's data from the subscriber's current Serving GPRS Support Node (SGSN) to the GGSN which is handling the subscriber's session. Three forms of GTP are used by the GPRS core network.

* GTP-U: for transfer of user data in separated tunnels for each PDP context
* GTP-C: for control reasons including:
o setup and deletion of PDP contexts
o verification of GSN reachability
o updates, e.g. as subscribers move from one SGSN to another.
* GTP' : for transfer of charging data from GSNs to the charging function.

GGSNs and SGSNs (collectively known as GSNs) listen for GTP-C messages on UDP port 2123 and for GTP-U messages on port 2152. This communication happens within a single network or may, in the case of international roaming, happen internationally, probably across a GPRS Roaming Exchange (GRX).

The "Charging Gateway Function" (CGF) listens to GTP' messages sent from the GSNs on UDP port 3386. The core network sends charging information to the CGF, typically including PDP context activation times and the quantity of data which the end user has transferred. However, this communication which occurs within one network is less standardised and may, depending on the vendor and configuration options, use proprietary encoding or even an entirely proprietary system.

Failed Short Message Delivery

When the VMSC/SGSN indicates a short message delivery failure, the SMSC may send a message to the HLR, using the MAP_REPORT_SM_DELIVERY_STATUS procedure, indicating the reason for the delivery failure and requesting that the SMSC be put on a list of service centres wanting to be notified when the destination party becomes available again. The HLR will set a flag against the destination account, indicating that it is unavailable for short message delivery, and store the SMSC's address in the Message Waiting Delivery (MWD) list for the destination party. Valid flags are Mobile Not Reachable Flag (MNRF), Memory Capacity Exceeded Flag (MCEF) and Mobile Not Reachable for GPRS (MNRG). The HLR will now start responding to SRI-for-SM requests with a failure, indicating the failure reason, and will automatically add the requesting SMSC's address to the MWD list for the destination party.

The HLR may be informed of a subscriber becoming available for short message delivery in several ways:

* Where the subscriber has been detached from the network, a reattach will trigger a Location Update to the HLR.
* Where the subscriber has been out of coverage, but not fully detached from the network, on coming back into coverage it will respond to page requests from the Visitor Location Register (VLR). The VLR will then send a Ready-for-SM (mobile present) message to the HLR.
* Where the MS has had its memory full, and the subscriber deletes some texts, a Ready-for-SM (memory available) message is sent from the VMSC/VLR to the HLR.

Upon receipt of an indication that the destination party is now ready to receive short messages, the HLR sends an AlertSC MAP message to each of the SMSCs registered in the MWD list for the subscriber, causing the SMSC to start the Short Message delivery process again, from the beginning.[1]

Additionally, the SMSC will go into a retry schedule, attempting to periodically deliver the SM without getting an alert. The retry schedule interval will depend on the original failure cause - transient network failures will result in short retry schedule, whereas out of coverage will typically result in a longer schedule.

Premium-Rated Short Messages

Short messages may be used to provide premium rate services to subscribers of a telephone network.

Mobile terminated short messages can be used to deliver digital content such as news alerts, financial information, logos and ring tones. The VASP providing the content submits the message to the mobile operator's SMSC(s) using a TCP/IP protocol such as the Short message peer-to-peer protocol (SMPP) or the External Machine Interface (EMI). The SMSC delivers the text using the normal Mobile Terminated delivery procedure. The subscribers are charged extra for receiving this premium content, and the amount is typically divided between the mobile network operator and the value added service provider (VASP) either through revenue share or a fixed transport fee.

Mobile originated short messages may also be used in a premium-rated manner for services such as televoting. In this case, the VASP providing the service obtains a Short Code from the telephone network operator, and subscribers send texts to that number. The payouts to the carriers vary by carrier and the percentages paid are greatest on the lowest priced premium SMS services. Most information providers should expect to pay about 45% of the cost of the premium SMS up front to the carrier. The submission of the text to the SMSC is identical to a standard MO Short Message submission, but once the text is at the SMSC, the Service Centre identifies the Short Code as a premium service. The SC will then direct the content of the text message to the VASP, typically using an IP protocol such as SMPP or EMI. Subscribers are charged a premium for the sending of such messages, with the revenue typically shared between the network operator and the VASP. Limitations of short codes include the limitation to national borders (short codes have to be activated in each country where the campaign takes place), as well as being expensive to sign up together with mobile operators.

An alternative to inbound SMS is based on Long Numbers (international number format, e.g. +44 7624 805000),which can be used in place of short codes for SMS reception in several applications, such as TV voting, product promotions and campaigns. Long Numbers are internationally available, as well as enabling businesses to have their own number, rather than short codes which are usually shared across a lot of brands. Additionally, Long Numbers are non-premium inbound numbers.

SMS in Satellite Phone Networks

All commercial Satellite phone networks except ACeS fully support SMS. While early Iridium handsets only support incoming SMS but later models can also send them. The price per message varies for the different networks and is usually between 25 and 50 cent per message. Unlike some mobile phone networks there is no extra charge for sending international SMS or to send one to a different satellite phone network. SMS can sometimes be sent from areas where the signal is too poor to make a voice call.

Satellite phone networks usually have a web-based or email-based SMS portals where one can send free SMS to phones on that particular network.

Landline Phone

These services allow cellphone users to send SMS messages to landline phone numbers just as they would to other cellphones. With a representative service, Sprint's Text to Landline, after the customer has sent off the SMS message to the landline number, the recipient's phone rings with the caller ID of the Sprint customer's cellphone. When they pick up, an automated voice reads the text message and allows for a response via a voicemail or via one of a few canned text messages.

Several operators, including BT, Telefonica and Telecom Italia, have true fixed-wire SMS services. These are based on extensions to the ETSI GSM SMS standards and allow fixed-fixed, fixed-mobile and mobile-fixed messaging. These use Frequency-shift keying to transfer the message between the terminal and the SMSC. Terminals are usually DECT-based, but wired handsets and wired text-only (no voice) devices exist. Messages are received by the terminal recognising that the CLI is that of the SMSC and going off-hook silently to receive the message.

When messages are addressed to a device that lacks the ability to receive SMS, then a text-to-speech gateway is employed. The translated message is then either stored in the subscriber's voice mail-box, or the system places a call direct to the end-point and plays the message.

SMS Gateway Appliances

SM messages are also used in corporate environment to enhance the company communication capabilities.

Some of the SMS to TCP/IP gateway appliance functions are:

• SMS to/from mail servers
• SMS to/from databases
• SMS to/from web script (PHP, ASP, JSP, etc...)
• SMS to/from Email clients
• SMS to/from desktop Widgets (MAC X OS, Windows, Linux)

Application fields for these small appliances:

• Radio or Television shows with live interaction with the public
• Data processing for alarms and measure/control units
• Designed to be easily integrated in ICT solutions
• Send and Receive SMS from a web site
• Send and receive SMS using your mailbox
• Perform statistics and surveys with real time reports
• Send massive SMS to a distribution list (SMS letter)
• Send news and feedback
• Link actions to send or receive event
• Control status of other servers and send alarms to the Webmaster
• Use SMS as input for a web order processing system
• Manage Requests of informations or reports and receive it via SMS

IP SMS Gateways

For high volume SMS traffic IP SMS gateways can be used. These gateways connect directly to the Short Message Service Center (SMSC) of the SMS service providers using one of the following protocols: SMPP, UCP/EMI, CIMD2. Most IP SMS gateways provide various API's that allow software developers to send and receive huge number of messages. An example of an IP SMS gateway is the Ozeki IP SMS Gateway. It is a classic example of a routable SMS gateway, which means it allows connection to multiple SMSC's at the same time and it has a routing table that can be configured for load balancing, least cost routing, etc. Most SMS to E-mail, and Web service to SMS gateways have a similar architecture.?