What Is a GSM Antenna?

A Global System for Mobile (GSM) antenna is a type of antenna commonly used in mobile phones and cell towers. Global System for Mobile Communications is the most common type of cellular network worldwide. The antenna in a GSM phone allows the device to communicate with another GSM antenna on a cell tower, which then relays the signal to another tower or to another cell phone. GSM service can be used on a number of radio frequencies, depending on the region and technology used. Many modern phones with GSM antennas support a variety of these frequencies so that they can be used while traveling.

Most modern mobile phones have an internal GSM antenna, usually contained in or near the bottom of the phone. Some older phones have an external pull-out antenna or a small bump of an antenna on the top of the phone. Both internal and external GSM antennas work in the same way.

Many smart phones have other antennas for additional technologies, such as wireless Internet connections. GSM also can be used to transfer data, for use in email or Web browsing on mobile phones. Many phones have a GSM antenna that is compatible with third-generation (3G) technology for much faster speeds.

Cell phone carriers use much larger antennas as part of their cell sites. These can be mounted high on a tower or structure. A cell phone often is within range of more than one cell site, and it selects one to use for a call or data transfer based on signal strength and congestion. Carriers sometimes will hide a large GSM antenna or disguise it to make it look more appealing.

A GSM antenna also can be found in a laptop, a netbook or a Universal Serial Bus (USB) device. In these cases, the antenna is meant only for data. It usually will use 3G technology to deliver quick wireless Internet service over a GSM network.

In areas with poor coverage, special devices are designed to increase or extend the cell phone signal, typically for more reliable indoor use. These devices, which can be called femtocells, microcells or GSM booster antennas, have larger antennas than those found on mobile phones but smaller than those of a traditional cell site. The device uses its larger antennas to reach distant cell towers, and it provides a strong signal to nearby phone that otherwise would receive a poor signal or no signal.

What Is a GSM Network?

The Global System for Mobile Communications (GSM) network is the standard system used by most mobile phone networks around the world. Whether a system uses a cellular network based around broadcast stations or satellite technology connected to signals from orbit, both types can be part of the GSM network. According to statistics accumulated by an organization known as the GSM Association, roughly 80 percent of all mobile phones around the world are part of this network. Phones on this type of network use a Subscriber Identity Module (SIM) card, while those on the major competing technology, Code Division Multiple Access (CDMA), do not.

Frequencies Used

The GSM network operates on different frequencies depending on the system used, whether 2G or 3G. Each frequency is then subdivided into different channels that allow for short bursts of digital information to be sent via the GSM connection. Networks in North America operate on different frequencies than those in Europe or Asia. Much of this has to do with the sheer volume of mobile phone use in certain parts of the world, and the fact that Canada and the United States had already allocated certain frequencies for other uses.

SIM Cards on GSM

Phones on a GSM network typically use a SIM card, which stores data about the phone and its user, allowing that information to be easily transferred to a different device. Many GSM providers use "SIM locking" to keep a person on a particular network during a contracted period of time. Once a contract is complete, then the card can be used in a new phone or on a different network. The competing technology, CDMA, does not use these cards and requires the data stored on a phone to be transferred over manually or through a connection.

History and Origin for GSM

Creation of the GSM network occurred in 1982 with a meeting between high-level communication experts at the European Conference of Postal and Telecommunications Administrations. Its original purpose was to address cellular infrastructure in Europe, but it quickly expanded to other nations. Many of the standards and operational procedures of the GSM network are published in annual journals. These help industry experts streamline communication protocols from one system to another.

     Originally, GSM stood for “Groupe Spécial Mobile”, named after the study group that created it, the European Telecommunications Standards Institute (ETSI) which developed a standard set to describe technologies for second generation (2G) digital cellular networks. The acronym was later changed to “Global System for Mobile communications”. This transition as well is one of the key aspects of GSM history, which elaborated subsequently in table below.

Table: Timeline of the development of GSM

Function of GSM

One of the main purposes of the GSM network is to facilitate easier access to cellular and satellite platforms across international lines. Using digital technology, it employs both speech and data channels in its system. At minimum, these channels operate on the second generation (2G) network, but many use the third generation (3G) system or higher to offer these services to clients.

This enables the exchange of information at high-speed data rates via satellites and mobile cellular towers across networks and company lines. For example, a person in Tokyo can text message someone in Toronto via Japan's system, through networks in the countries between, until it finally arrives on the recipient's mobile device in Canada. In particular, the network has been essential in establishing worldwide access to emergency telephone services using the digits one-one-two (112), redirecting global phone traffic to emergency responders in a user's proximity. It is also responsible for establishing text message technology during the 1990s.

Global System for Mobile Communication

Smart Sharp Vehicle Tracking requires a medium to transmit and receive SMS. The medium transfers for SMS are GSM. GSM is a cellular network, which means that mobile phones connect to it by searching for cells in the immediate vicinity. GSM networks operate in four different frequency ranges. Most GSM networks operate in the 900 MHz or 1800 MHz bands. Some countries in the Americas (including Canada and the United States) use the 850 MHz and 1900 MHz bands because the 900 and 180 MHz frequency bands were already allocated. The rarer 400 and 450 MHz frequency bands are assigned in some countries, notably Scandinavia, where these frequencies were previously used for first-generation systems.

What is GSM Modem?

A GSM modem is a specialized type of modem which accepts a SIM card, and operates over a subscription to a mobile operator, just like a mobile phone. From the mobile operator perspective, a GSM modem looks just like a mobile phone.

When a GSM modem is connected to a computer, this allows the computer to use the GSM modem to communicate over the mobile network.  While these GSM modems are most frequently used to provide mobile internet connectivity, many of them can also be used for sending and receiving SMS and MMS messages.

A GSM modem can be a dedicated modem device with a serial, USB or Bluetooth connection, or it can be a mobile phone that provides GSM modem capabilities.

For the purpose of this document, the term GSM modem is used as a generic term to refer to any modem that supports one or more of the protocols in the GSM evolutionary family, including the 2.5G technologies GPRS and EDGE, as well as the 3G technologies WCDMA, UMTS, HSDPA and HSUPA.

A GSM modem exposes an interface that allows applications such as NowSMS to send and receive messages over the modem interface. The mobile operator charges for this message sending and receiving as if it was performed directly on a mobile phone. To perform these tasks, a GSM modem must support an “extended AT command set” for sending/receiving SMS messages, as defined in the ETSI GSM 07.05 and 3GPP TS 27.005 specifications.

GSM modems can be a quick and efficient way to get started with SMS, because a special subscription to an SMS service provider is not required. In most parts of the world, GSM modems are a cost effective solution for receiving SMS messages, because the sender is paying for the message delivery.

A GSM modem can be a dedicated modem device with a serial, USB or Bluetooth connection, such as the Falcom Samba 75. (Other manufacturers of dedicated GSM modem devices include Wavecom, Multitech and iTegno.  We’ve also reviewed a number of modems on our technical support blog.) To begin, insert a GSM SIM card into the modem and connect it to an available USB port on your computer.

A GSM modem could also be a standard GSM mobile phone with the appropriate cable and software driver to connect to a serial port or USB port on your computer. Any phone that supports the “extended AT command set” for sending/receiving SMS messages, as defined in ETSI GSM 07.05 and/or 3GPP TS 27.005, can be supported by the Now SMS & MMS Gateway. Note that not all mobile phones support this modem interface.

Due to some compatibility issues that can exist with mobile phones, using a dedicated GSM modem is usually preferable to a GSM mobile phone. This is more of an issue with MMS messaging, where if you wish to be able to receive inbound MMS messages with the gateway, the modem interface on most GSM phones will only allow you to send MMS messages. This is because the mobile phone automatically processes received MMS message notifications without forwarding them via the modem interface.

It should also be noted that not all phones support the modem interface for sending and receiving SMS messages. In particular, most smart phones, including Blackberries, iPhone, and Windows Mobile devices, do not support this GSM modem interface for sending and receiving SMS messages at all at all. Additionally, Nokia phones that use the S60 (Series 60) interface, which is Symbian based, only support sending SMS messages via the modem interface, and do not support receiving SMS via the modem interface.

Introduction for Smart Sharp Vehicle Tracking

          Year after year, the case of motorcycle theft is growing rapidly in Malaysia. Statistics released by the police revealed that 5,920 motorcycle stolen between January and October last year. As the owner of the motorcycle, a security system is needed to protect us from the dangers of motorcycles. There is no way to completely eliminate the theft of a motorcycle, but still no way to prevent bike from being stolen and going. Thus, Sharp Smart Vehicle Tracking is created as an approach to protect the motorcycle. This system is a security system designed to protect and warn the user when a specific case that requires immediate attention to motorcycles. When any sensor activated motorcycle alarm system, this module will notify the owner of SMS motorcycle. This project is a design using a transmitter, which sends a signal to a receiver device that contains a link to the control system is defined as a PIC microcontroller. The alarm will arm and it will try the voltage then sent to the PIC microcontroller. Programming Micro- P Compiler can be used to monitor and control signals for the modem to connect the serial port RS232 communication between GSM modem and hardware. AT commands are used to control the functions of a modem.