What is the importance of GSM?

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Majority of the carriers worldwide use GSM technology, wherein SIM cards are utilized to store information, like contacts, and data. With this technology, it's just easy to use different phones without losing data or contacts.
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What is GSM?

GSM is a technology which is the leading cell phone standard all over the world. In 1982 it was recognized as a standard for digital wireless communications and was first adopted in Europe and then by Asia, Africa etc. The first system was online in 1991 and GSM was formerly known as Group Special Mobile but now stands for Global System for Mobile communications. USA, however has not adopted GSM as a standard and so different carriers now use different technologies as opposed to only GSM. GSM uses digital technology and the methods of time division multiple access transmission. In GSM, sound is digitally prearranged through a special encoder, which imitates the distinctiveness of human speech. This method of transmission allows a very competent statistics speed/information content ratio. GSM is an open system and is a non propriety technology. One of the great benefits of GSM is that it facilitates international roaming. As it is adopted by more than 170 countries, you have the facility of using your GSM cell phone in all these places without having to change your number. GSM satellite roaming has broadened the scope of cellular services even to areas where standard terrestrial services are not possible. GSM is a technology that is rapidly growing and constantly evolving with wireless, satellite and cordless systems offering greatly expanded services. These services include multimedia data services, high speed, inbuilt support for side by side use of these services and faultless incorporation with the Internet and wireline networks. 3GSM (next generation of mobile communications services) is already charted out and will make available services enhancing the already existing voice, data, and text services. GSM will provide video on demand and will help to lessen the gap between wireless and internet/computers. GSM works on different frequency bands across the world. In North America it uses a 1900 MHz frequency whereas in other parts of the world it uses either 900MHz or 1800 MHz. As different frequencies are used in different places, your GSM handset should support various bands so that it can be used globally. From the beginning, GSM has been developed with the need to give its customers utmost security in terms of secure communications, fraud prevention, and call privacy. Today it is the worlds most secure public wireless standard for cellular phones. In an entirely different context, GSM could also stand for grams per square metre. This is the standard measure used for paper, and fabrics.

What services does gsm provide?

GSM SERVICES . GSM services . GSM services are a standard collection of applications and features available to mobile phone subscribers all over the world. The GSM standards are defined by the 3GPP collaboration and implemented in hardware and software by equipment manufacturers and mobile phone operators . The common standard makes it possible to use the same phones with different companies' services, or even roam into different countries. GSM is the world's most dominant mobile phone standard.. The design of the service is moderately complex because it must be able to locate a moving phone anywhere in the world, and accommodate the relatively small battery capacity, limited input/output capabilities, and weak radio transmitters on mobile devices.. Contents . [ hide ]. 1 Accessing a GSM network 2 Voice calls 2.1 How outgoing calls are made from a mobile 2.2 How incoming calls are made to a mobile 2.2.1 Step One: Contact the Gateway MSC 2.2.2 Step Two: Determine how to route the call 2.2.3 Step Three: Ringing the phone 2.3 Voice charges 2.4 How speech is encoded during mobile phone calls 3 Data transmission 3.1 Circuit-switched data protocols 3.2 General Packet Radio Service (GPRS) 3.3 Short Message Service (SMS) 4 Supplementary Services 5 External links . [ edit ] Accessing a GSM network . In order to gain access to GSM services, a user needs three things: . A subscription with a mobile phone operator . This is usually either a Pay As You Go arrangement, where all GSM services are paid for in advance, or a Pay Monthly option where a bill is issued each month for line rental, normally paid for a month in advance, and for services used in the previous month.. A mobile phone which is GSM compliant and operates at the same frequency as the operator. Most phone companies sell phones from third-party manufacturers.. A SIM card which is issued by the operator once the subscription is granted. The card comes pre-programmed with the subscriber's phone "identity" and will be used to store personal information (like contact numbers of friends and family). . After subscribers sign up, information about their phone's identity and what services they are allowed to access are stored in a "SIM record" in the Home Location Register (HLR). The Home Location Register is a database maintained by the "home" phone company for all of its subscribers. It is used to answer queries like, "Where on the mobile phone network is the device associated with this phone number?" and "What services is this subscriber paying for?". Once the SIM card is loaded into the phone and it is powered on, it will search for the nearest mobile phone mast, also called a Base Transceiver Station or BTS. If a mast can be successfully contacted, then there is said to be coverage in the area.. Stationary phones are always connected to the same part of the phone network, but mobile phones can "visit" any part of the network, whether across town or in another country via a foreign provider. Each geographic area has a database called the Visitors Location Register (VLR) which contains details of all the local mobiles. Whenever a phone attaches, or visits, a new area, the Visitors Location Register must contact the Home Location Register.. The Visitors LR will tell the Home LR where the phone is connected to the network (which VLR), and will ask it for a copy of the SIM record (which includes, for example, what services the phone is allowed to access). The current cellular location of the phone (i.e. which BTS it is at) is entered into the VLR record and will be used during a process called paging when the GSM network wishes to locate the mobile phone .. Every SIM card contains a secret key, called the Ki, which it uses to prove its identity to the phone network (to prevent theft of services) upon first contact. The network does this by consulting the Authentication Center of the "home" phone company, which also has a copy of the secret key. (Though the authentication is accomplished without transmitting the key directly.). Every phone contains a unique identifier (different from the phone number, which is associated at the HLR with the removable SIM card), called the International Mobile Equipment Identity (IMEI). When a phone contacts the network, its IMEI is supposed to be checked against the global Equipment Identity Register to locate stolen phones and facilitate monitoring.. [ edit ] Voice calls . [ edit ] How outgoing calls are made from a mobile . Once a mobile phone has successfully attached to a GSM network as described above, calls may be made from the phone to any other phone on the global Public Switched Telephone Network assuming the subscriber has an arrangement with their "home" phone company to allow the call.. The user dials the telephone number , presses the send or talk key, and the mobile phone sends a call setup request message to the mobile phone network via the mobile phone mast (BTS) it is in contact with.. The element in the mobile phone network that handles the call request is the Visited Mobile Switching Center (Visited MSC). The MSC will check against the subscriber's temporary record held in the Visitor Location Register to see if the outgoing call is allowed. If so, the MSC then routes the call in the same way that a telephone exchange does in a fixed network.. If the subscriber is on a Pay As You Go tariff (sometimes known as Prepaid (for example, in Australia)), then an additional check is made to see if the subscriber has enough credit to proceed. If not, the call is rejected. If the call is allowed to continue, then it is continually monitored and the appropriate amount is decremented from the subscriber's account. When the credit reaches zero, the call is cut off by the network. The systems that monitor and provide the prepaid services are not part of the GSM standard services, but instead an example of intelligent network services that a mobile phone operator may decide to implement in addition to the standard GSM ones.. [ edit ] How incoming calls are made to a mobile . [ edit ] Step One: Contact the Gateway MSC . When someone places a call to a mobile phone , they dial the telephone number (also called a MSISDN ) associated with the phone user and the call is routed to the mobile phone operator 's Gateway Mobile Switching Centre. The Gateway MSC , as the name suggests, acts as the "entrance" from exterior portions of the Public Switched Telephone Network onto the provider's network.. As noted above, the phone is free to roam anywhere in the operator's network or on the networks of roaming partners, including in other countries. So the first job of the Gateway MSC is to determine the current location of the mobile phone in order to connect the call. It does this by consulting the Home Location Register ( HLR ), which, as described above, knows which Visitor Location Register ( VLR ) the phone is associated with, if any.. [ edit ] Step Two: Determine how to route the call . When the HLR receives this query message, it determines whether the call should be routed to another number (called a divert), or if it is to be routed directly to the mobile. . If the owner of the phone has previously requested that all incoming calls be diverted to another number, known as the Call Forward Unconditional (CFU) Number, then this number is stored in the Home Location Register. If that is the case, then the CFU number is returned to the Gateway MSC for immediate routing to that destination. . If the mobile phone is not currently associated with a Visited Location Register (because the phone has been turned off or is not in range) then the Home Location Register returns a number known as the Call Forward Not Reachable (CFNRc) number to the Gateway MSC, and the call is forwarded there. Many operators may set this value automatically to the phone's voice mail number, so that callers may leave a message. The mobile phone may sometimes override the default setting. . Finally, if the Home Location Register knows that the phone is in the jurisdiction of a particular Visited Location Register , then it will request a temporary number (called an MSRN ) from that VLR. This number is relayed to the Gateway MSC, which uses it to route the call to another Mobile Switching Center, called the Visiting MSC. . [ edit ] Step Three: Ringing the phone . When the call is received by the Visiting MSC, the MSRN is used to find the phone's record in the Visited Location Register. This record identifies the phone's location area . Paging occurs to all mobile phone masts in that area. When the subscriber's mobile responds, the exact location of the mobile is returned to the Visited MSC. The VMSC then forwards the call to the appropriate phone mast, and the phone rings. If the subscriber answers, a speech path is created through the Visiting MSC and Gateway MSC back to the network of the person making the call, and a normal telephone call follows.. It is also possible that the phone call is not answered. If the subscriber is busy on another call (and call waiting is not being used) the Visited MSC routes the call to a pre-determined Call Forward Busy (CFB) number. Similarly, if the subscriber does not answer the call after a period of time (typically 30 seconds) then the Visited MSC routes the call to a pre-determined Call Forward No Reply (CFNRy) number. Once again, the operator may decide to set this value by default to the voice mail of the mobile so that callers can leave a message..... [ edit ] Voice charges . In the United States and Canada, callers pay the cost of connecting to the Gateway MSC of the subscriber's phone company, regardless of the actual location of the phone. As mobile numbers are given standard geographic numbers according to the North American Numbering Plan , callers pay the same to reach fixed phones and mobile phones in a given geographic area. Mobile subscribers pay for the connection time (typically using in-plan or prepaid minutes) for both incoming and outgoing calls. For outgoing calls, any long distance charges are billed as if they originate at the GMSC, even though it is the Visiting MSC which completes the connection to the PSTN. Plans that include nationwide long distance and/or nationwide roaming at no additional charge over "local" outgoing calls are popular.. Mobile networks in Europe, Asia and Australia only charge their subscribers for outgoing calls. Incoming calls are free to the mobile subscriber; however, callers typically pay a higher rate when calling mobile phones. Special prefixes are used to designate mobile numbers so that callers are aware they are calling a mobile phone and therefore will be charged a higher rate.. From the caller's point of view, it does not matter where the mobile subscriber is, as the technical process of connecting the call is the same. If a subscriber is roaming on a different company's network, the subscriber, instead of the caller, may pay a surcharge for the connection time. International roaming calls are often quite expensive, and as a result some companies require subscribers to grant explicit permission to receive calls while roaming to certain countries.. When a subscriber is roaming internationally and a call is forwarded to his or her voice mail, such as when his or her phone is off, busy, or not answered, he or she may actually be charged for two simultaneous international phone calls—the first to get from the GMSC to the VMSC and the second to get from the VMSC to the Call Forward Busy or Call Forward No Reply number (typically the voice mailbox) in the subscriber's country. However, some networks' GMSCs connect unanswered calls directly, keeping the voice signal entirely within the home country and thus avoiding the double charge. [ citation needed ] . [ edit ] How speech is encoded during mobile phone calls . During a GSM call, speech is converted from analogue sound waves to digital data by the phone itself, and transmitted through the mobile phone network by digital means. (Though older parts of the fixed Public Switched Telephone Network may use analog transmission.). The digital algorithm used to encode speech signals is called a codec . The speech codecs used in GSM are called Half-Rate (HR) , Full-Rate (FR) , Enhanced Full-Rate (EFR) and Adaptive Multirate (AMR) . All codecs except AMR operate with a fixed data rate and error correction level.. [ edit ] Data transmission . The Public Switched Telephone Network (PSTN) is essentially a collection of interconnected systems for taking an audio signal from one place and delivering it to another. Older analogue phone networks simply converted sound waves into electrical pulses and back again. The modern phone system digitally encodes audio signals so that they can be combined and transmitted long distances over fiber optic cables and other means, without losing signal quality in the process. When someone uses a computer with a traditional modem , they are encoding a (relatively slow) data stream into a series of audio chirps, which are then relayed by the PSTN in the same way as regular voice calls. This means that computer data is being encoded as phone audio, which is then being re-encoded as phone system data, and then back to phone quality audio, which is finally converted back to computer data at the destination.. GSM voice calls are essentially an extension of the PSTN, dealing only with audio signals. Behind the scenes, we know these audio channels happen to be transmitted as digital radio signals.. The GSM standard also provides separate facilities for transmitting digital data directly , without any of the inefficient conversions back and forth to audio form. This allows a mobile "phone" to act like any other computer on the Internet , sending and receiving data via the Internet Protocol or X.25 .. The mobile may also be connected to a desktop computer, laptop , or PDA , for use as a network interface. (Like a modem or ethernet card, but using a GSM-compatible data protocol instead of a PSTN-compatible audio channel or an ethernet link to transmit data.) Newer GSM phones can be controlled by a standardised Hayes AT command set through a serial cable or a wireless link (using IrDA or Bluetooth ). The AT commands can control anything from ring tones to data compression algorithms.. In addition to general Internet access, other special services may be provided by the mobile phone operator , such as SMS .. [ edit ] Circuit-switched data protocols . A circuit-switched data connection reserves a certain amount of bandwidth between two points for the life of a connection, just as a traditional phone call allocates an audio channel of a certain quality between two phones for the duration of the call. (But remember that in the GSM system, there is no need to use audio signals to create data connections, even circuit-switched ones. The idea of a circuit-switched data connection being like a phone call is just an analogy to help explain the idea.). Two circuit-switched data protocols are defined in the GSM standard, and they have not-very-creative names: Circuit Switched Data (CSD) and High-Speed Circuit-Switched Data (HSCSD). These types of connections are typically charged on a per-second basis, regardless of the amount of data sent over the link. This is because a certain amount of bandwidth is dedicated to the connection regardless of whether or not it is needed.. Circuit-switched connections do have the advantage of providing a constant, guaranteed quality of service , which is useful for real-time applications like video conferencing.. [ edit ] General Packet Radio Service (GPRS) . A packet-switched connection chops data into distinct chunks, known as packets, which may arrive at their destination via different routes, at different times, out of sequence, or (hopefully only occasionally) not at all. An intermediate protocol, like TCP , might be used to ensure the original data stream is reassembled at the destination (by putting packets in order and retransmitting missing ones, if necessary).. The General Packet Radio Service (GPRS) is a packet-switched data transmission protocol which was incorporated into the GSM standard in 1997. It is backwards-compatible with systems that use pre-1997 versions of the standard. GPRS does this by sending packets to the local mobile phone mast ( BTS ) on channels not being used by circuit-switched voice calls or data connections. Multiple GPRS users can share a single unused channel because each of them uses it only for occasional short bursts.. The advantage of packet-switched connections is that bandwidth is only used when there is actually data to transmit. This type of connection is thus generally billed by the kilobyte instead of by the second, and is usually a cheaper alternative for applications that only need to send and receive data sporadically, like instant messaging .. GPRS is usually described as a 2.5G technology; see the main article for more information.. [ edit ] Short Message Service (SMS) . Main article: Short message service . The GSM standards first defined the structure of a Short Message, and provide a means of transmitting messages between mobile devices and Short Message Service Centres via the Short message service (SMS). SMS messages may be carried between phones and SMSCs by any of the circuit-switched or packet-switched methods described above or, more typically, by the MAP protocol through the SS7 signaling channel used for call setup.. SMSCs can be thought of as central routing hubs for Short Messages. Many mobile service operators use their SMSCs as gateways to external systems, including the Internet , incoming SMS news feeds, and each other (often using the de facto SMPP standard).. The SMS standard is also used outside of the GSM system; see the main article for details.. [ edit ] Supplementary Services . GSM supports a comprehensive set of supplementary services that complement and support the telephony and data services described above. They are all defined in GSM standards. (See GSM codes for supplementary services ) A partial listing of supplementary services follows. . Call Forwarding . This service gives the subscriber the ability to forward incoming calls to another number if the called mobile unit is not reachable, if it is busy, if there is no reply, or if call forwarding is allowed unconditionally. . Barring of Outgoing Calls . This service makes it possible for a mobile subscriber to prevent all outgoing calls. . Barring of Incoming Calls . This function allows the subscriber to prevent incoming calls. The following two conditions for incoming call barring exist: baring of all incoming calls and barring of incoming calls when roaming outside the home PLMN. . Advice of Charge (AoC) . The AoC service provides the mobile subscriber with an estimate of the call charges. There are two types of AoC information: one that provides the subscriber with an estimate of the bill and one that can be used for immediate charging purposes. AoC for data calls is provided on the basis of time measurements. . Call Hold . This service enables the subscriber to interrupt an ongoing call and then subsequently reestablish the call. The call hold service is only applicable to normal telephony. . Call Waiting . This service enables the mobile subscriber to be notified of an incoming call during a conversation. The subscriber can answer, reject, or ignore the incoming call. Call waiting is applicable to all GSM telecommunications services using a circuit-switched connection. . Multiparty service . The multiparty service enables a mobile subscriber to establish a multiparty conversation - that is, a simultaneous conversation between three and six subscribers. This service is only applicable to normal telephony. . Calling Line Identification presentation/restriction . These services supply the called party with the integrated services digital network (ISDN) number of the calling party. The restriction service enables the calling party to restrict the presentation. The restriction overrides the presentation. . Closed User Groups (CUGs) . CUGs are generally comparable to a PBX. They are a group of subscribers who are capable of only calling themselves and certain numbers. . Explicit Call Transfer (ECT) . This service allows a user who has two calls to connect these two calls together and release its connections to both other parties. . [ edit ] External links . BBC 3 Investigates video BBC3 programme "investigates" has undertaken the largest ever survey of the proximity to schools of mobile phone masts in the UK.. GSM Call Flows and Sequence Diagrams Detailed call flow diagrams describing GSM call setup, location update and handover. .

What is GSM Radar on your mobile?

Answer . It's a scam. It's a screen saver. It's not radar at all. It costs 15 euros a month and it's just a rip off. This is what's wrong with capitalism.

What are the disadvantages of gsm?

Answer . well so far gsm hasn't got a spread spectrum technology, the data packe ts are not coded appropriately thus loss of data

What is GSM communications?

GSM stands for "Global System for Mobile communications", which was a replacement for the former AMPS and TDMA (Time Division Multiple Access) formats of analog cellular telephone transmissions. GSM is currently used by over 3 billion people across more than 212 countries and territories, over 82% of the world's population. GSM's advantage over its predecessor is that it is 100% digital, as opposed to TDMA, which was analog. While covering a shorter distance than the analog signal, a GSM signal can carry more voice and data communications than the analog band, and carry it at a faster rate, thus making GSM a "second-generation" (2G) cellular technology. 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 1800 MHz frequency bands were already allocated.

How do you jam GSM?

A high power RF emitter wold do the job. However, if you do it successfully, a lot of people will get real upset about not being able to use the GSM networks, they complain and the local radio licensing authority will be out to investigate. Then, you are in huge trouble. Probably not wise to do it.. Alternatively, if it is to prevent GSM devices being used inside a building, a Farady cage might work. It is made of metal sheets that enclose a room or building, all connected to each other and all connected to ground. Effective, but expensive and it cuts out all other RF signals as well.. Answer . For "local" control of the airwaves, a low power transmitter can be used as a "jammer" on these frequencies. That will allow z"quiet" in areas that one wishes to control things. A movie theater, perhaps. But any attempt to "push the envelope" will be met with Federal force. Check around before running loose on this.. The FCC controls the airwaves, and they aren't very patient with the patent infringement of the rights of mobile communicators to use those airwaves. And they have a little van with a couple of geeks in it to track you down. They're well equiped and good at it.. Trying to seal a building against electronic communication is difficult and expensive, particularly if you have "variable" openings in it where people and/or vehicles are coming and going.

What is gsm uplink?

Hi,. For every GSM band there are Uplink and downlink frequencies.. Example:. GSM 900 TX: 880 MHz to 915 MHz is an uplink frequency range. GSM 900 RX: 925 MHz to 960 MHz is a downlink frequency range. Aloha,. Maverick

How do you send sms on computers with GSM?

If you have a nokia unit, you can try the program from Nokia called PC-Suite, it will send and receive SMS as well as handle other functions of your phone.

What is E-GSM?

E-GSM is the band of frequency in a small radio or a wireless phone. The band is 880-A890 MHz small radio frequency band used in Europe to provide added network capacity for GSM 900 networks.\n\n\n\n

What are rayban gsm lenses?

GSM label in RayBan sunglasses stands for Gradient Silver Mirror . This is mainly found in Polarized models, where the upper zone of the lens is darker than the bottom (in a gradient way), and the exterior side (opposite from where you look when wearing on them) has a silver mirror effect.

What is the GSM?

GSM Stands for Global System foe Mobile Communications.It uses TDMA and FDMA accessing techniques for effective utilization of frequency spectrum.

Why is the gsm 900 better than gsm 1800 and gsm 1900?

As the frequency increase its penetration power decreases.The signal travels a lesser distance.Hence for a perticular area more no of towers need to be erected in 1800/1900 than in 900MHZ for full coverage...Hence vodafone( 1800MHZ) has more towers per unit area than Idea Cellular ( 1800+900) ..... Band of 900 is from 890-915( uplink) 935-960Mhz( downlink).... Band of 1800 is from 1710-1785(uplink) and 1805-1880MHZ(Downlink).... Same property is followed here.....The uplink is lower ( MOBILE -BTS) than the downlink frequency (BTS-MOBILE)...so that this may help the uplink signal to travel futher without consuming much power...BTS due to its increased power ,has higher frequency to tavel the same distance....

Disadvantages of the GSM technologies?

Dropped and Missed Calls . According to Cellular News, call quality problems, including dropped calls and missed calls are common problems with GSM technology. These problems result directly from the technology in use. GSM technology cannot accommodate as many callers on a single cell tower as the more modern CDMA technology. This means that callers in areas where there are not a preponderance of cell towers may find that the call problems on GSM will be more common.. Security Issues . ZDNet UK reports that GSM has a serious security flaw, demonstrated by a hacker who was able to intercept phone calls from a number of GSM-based cellular phones. The problem is based directly on the technology according to this hacker and his solution was to "turn off" the GSM technology (only the older 2G technology though) that is commonly used by people all over the world. The problem is largely mitigated however by the use of the more modern 3G technology that is commonly used (as of November, 2010) on many GSM phones.. Efficiency . Another problem with GSM is a network problem rather than a consumer problem, though it is a consumer problem for those who don't want to see a proliferation of cellular towers. As previously noted, GSM technology can handle fewer callers on a single cellular tower. Therefore, networks who work with GSM must find ever more areas to built GSM cellular towers, causing them to have problems with costs and locations. By the same token, some consumers who prefer not to see a proliferation of cellular towers consider this a problem because the cellular towers must be placed in more and more urban areas, potentially spreading more radiation and causing what some consider a blight on the landscape..

Does Vodafone have CDMA or GSM facility?

The Vodafone group operates in 16 different countries in Europe.. Vodafone-Germany operates both GSM and UMTS (W-CDMA) networks.

What are advanteges of GSM?

There are many benefits to GSM phone service and perhaps the best is that you can use cell phone with other provider. It is nice when using a cell phone that you can call whoever you want wherever you want and never think twice about changing mobile phone network or what frequency the phone is using. Everything just happens naturally, and that is certainly a benefit. And if you travel internationally you can still use your phone. This is where GSM comes into play and why it is so important to have a GSM cell phone. . You would get your GSM phone that is a Quad Band phone. In summary, a Quad Band mobile phone is used to designate a phone that can operate in the following GSM frequency bands : . 850 MHz (U.S./Canada/Latin America/Brazil (Only the carrier Vivo in the south and south-east of Brazil)) . 900 MHz (Africa/Europe/Brazil/Australia/Asia (ex Japan and S. Korea)) . 1800 MHz (Africa/Europe/Brazil/Australia/Asia) . 1900 MHz (U.S./Canada/Latin America/Brazil (Only the carrier Vivo in the north, north-east and centre-west of Brazil)) . These are also called World phones. These phones come unlocked and can be used with any carrier that uses a GSM network by changing the SIM card to the phone. To view some types of these phones go to: http:/nextlevelcellular.ecrater.com

Gsm 900 vs gsm 1800?

GSM-900 and GSM-1800 . GSM-900 and GSM-1800 are used in most parts of the world: Europe, Middle East, Africa, Australia and most of Asia. In South and Central America the following countries use the following:. * Costa Rica - GSM-1800 . Brazil - GSM-850, 900 and 1800 . Guatemala - GSM-850, GSM-900 and 1900 . El Salvador - GSM-850, GSM-900 and 1900 . GSM-900 uses 890-915 MHz to send information from the mobile station to the base station (uplink) and 935-960 MHz for the other direction (downlink), providing 124 RF channels (channel numbers 1 to 124) spaced at 200 kHz. Duplex spacing of 45 MHz is used. Guard bands 100 kHz wide are placed at either end of the range of frequencies [1] .. In some countries the GSM-900 band has been extended to cover a larger frequency range. This 'extended GSM', E-GSM, uses 880-915 MHz (uplink) and 925-960 MHz (downlink), adding 50 channels (channel numbers 975 to 1023 and 0) to the original GSM-900 band. The GSM specifications also describe 'railways GSM', GSM-R, which uses 876-915 MHz (uplink) and 921-960 MHz (downlink). Channel numbers 955 to 1023. GSM-R provides additional channels and specialized services for use by railway personnel. . All these variants are included in the GSM-900 specification. . GSM-1800 uses 1710-1785 MHz to send information from the mobile station to the base tranceiver station (uplink) and 1805-1880 MHz for the other direction (downlink), providing 374 channels (channel numbers 512 to 885). Duplex spacing is 95 MHz.. GSM-1800 is also called DCS (Digital Cellular Service) in the United Kingdom, while being called PCS in Hong Kong [2] (not to mix up with GSM-1900 which is commonly called PCS in the rest of the world.) .

What is a GSM and how does it work?

Gsm is a mobile coverage statement. Some of the gsm carriers are in lists on google. If you have a phone that is gsm capable, then get a gsm carrier SIM card that has your plan, and insert it into the phone. Then you will have to activate it, and it will work just like you bought it from the carrier.

What is a GSM modem?

GSM is the world's most popular standard for mobile telephony systems. GSM modem connect your computer to that. Allow computer to make cellphone call. And required sim.

What is GSMS?

this is where the chemical CG and MS come together to make GSMS, they can also can be taken away (separated) to be identified

What GSM stands for?

previously GSM stands for Groupe Special Mobile in US .since GSM is accepted as worldwide standard for mobile communication it was stated as Global System for Mobile communication.

What does gsm mean-measurement of paper?

GSM means Global System for Mobile Communications. This is the most commonly used technology by the carriers or network providers worldwide. However in paper production, it refers to Grams per Square Meter. Normallly, the higher the GSM, the thick the sheet of paper.

What does 80 gsm paper mean?

GSM means grams per square meter in measurement. It is the measure of the weight and type

How does a GSM Gateway work?

GSM Gateways work by inserting a normal Mobile SIM Card into the device, and once signal has been found the device is cabable of routing numbers out via the SIM Card. The typical solution would be to route mobile calls via the SIM card, effectively turning the call from Landline to mobile, to Mobile to mobile, cutting the cost by over half. GSM Gateways come in various different shapes, sizes and languages, by languages I mean protocols, e.g. ISDN30e/PRI, ISDN2/BRI, Analogue and VoIP Including H.323 and SIP, depending on what is needed for the company. For example, for a typical 2 person company, the most cost effective would be the analogue device and connect this to the original analogue line (just like your home phone) GSM Gateways also come with other features including inbound routing, Mobility solutions and overseas solutions - but we wont get into that, its much more technical - I should know, I installed them for a living!

How GSM modem works?

GSM moderm picks up signals from the surrounding wifi or either with the local internet connection which usually comes with a wired copper cable or fibre optic cable.

What is GSM in mobile phones?

GSM stands for Global System for Mobile communications. It is the most popular standard for mobile phone systems in the world, with over 80% of mobile phone users owning a GSM phone.

What is channel coding in GSM?

The GSM Channel Coding Channel coding introduces redundancy into the data flow in order to allow the detection or even the correction of bit errors introduced during the transmission. The speech coding algorithm produces a speech block of 260 bits every 20 ms (i.e. bit rate 13 kbit/s). In the decoder, these speech blocks are decoded and converted to 13 bit uniformly coded speech samples. The 260 bits of the speech block are classified into two groups. The 78 Class II bits are considered of less importance and are unprotected. The 182 Class I bits are split into 50 Class Ia bits and 132 Class Ib bits. Class Ia bits are first protected by 3 parity bits for error detection. Class Ib bits are then added together with 4 tail bits before applying the convolutional code with rate and constraint length K =5. The resulting 378 bits are then added to the 78 unprotected Class II bits resulting in a complete coded speech frame of 456 bits.

What is future of GSM?

The Limitations of GSM However, GSM is a technology of the mid 1980s where the only usage envisaged for a mobile phone is that of transmitting and receiving voice data. In fact, basic GSM phones only send and receive data at an apalling transmission rate of 9.6 kbps (kilobits per second). However, as mobile phones have grown into multimedia devices and text messaging has proved to be the 'killer app' - the one usage that brought mass appeal to mobile phones - then the data throughput limit has proved to be a real bottleneck. It's even possible to access the text content of web pages that have been converted to WAP (Wireless Access Point) format with a GSM phone. Unfortunately, due to the slow data transfer of GSM phones it can actually take several minutes to download even a WAP-converted page to your phone. In Japan this limitation was overcome by the DoCoMo company with their extremely successful I-mode range of mobile phones which can transfer data at ten times the speed of standard GSM. Standard GSM uses circuit switching as a means of data transfer. This means that the phone must make a dedicated connection with the base station thus tying-up the channel completely for that phone. In contrast, I-mode uses technology borrowed from the Internet, called packet switching where the transferred data is broken up into blocks called 'packets'. Each packet is labelled with the address of the final destination and any packet can be transferred on any available channel and no channel is dedicated to any telephone. Because of this data transfer proceeds at a much, much, higher rate. Not only are downloads quicker, but as the phone is only connected to the network when a package of information is being sent users pay for the amount of data they have sent rather than for the total time they remain connected. It is planned that all GSM networks will move to packet switching technology, which can only be of benefit to customers and it envisaged that data transfer rates will reach up to 171 kbps with the introduction of a system called GPRS ( G eneral P acket R adio S ervice) which not only splits the mobile phone call into packets but also allows each phone to use several channels which are shared amongst many users. Thus not only is data transfer speed increased but overall throughput is also increased. Beyond GSM - 3G 3G, which stands for 'Third Generation' is the great white hope of many mobile operators. The International Telecommunication Union (ITU) has defined the demands for third generation mobile networks with the IMT-2000 standard. An organisation called 3GPP has continued that work by defining a mobile system that fulfils the IMT-2000 standard. This system is called Universal Mobile Telecommunications System (UMTS). The first stage in the evolution of GSM to UTMS is the introduction of GPRS to all GSM services. Another advance in 3G systems is CDMA ( C ode D ivision M ultiple A ccess) which allows a single 'burst' of data to carry several signals simultaneously. This further compresses the amount of data that can be sent in a single data burst and, theoretically at least, allows for a maximum data transfer rate of up to 2 Mbps (megabits per second). It is this increased data transfer rates that allows 3G services to deliver video to its subscribers and which should also allow video messaging between 3G mobile phones. It is the hope of the nascent 3G providers that this video communication will be 'killer application' that drive through the sales of 3G phones and systems (just as texting did for GSM).

How do calculate fabric gsm?

The way that a fabric gsm (grams per square meter) would be calculated would be for a person/manufacturer, to make a swatch, one meter square, and then weigh it. Then they would know the grams per square meter. Each type of fabric would have a different weight. For example, a heavy corduroy would weigh more than a silk fabric of the same size.

What is ciphering in gsm?

Ciphering is encyption and decyption of user ID in GSM network. It is done inside GSM GPRS component SGSN.

What is an e1 in gsm?

e1 is a standard unit used to measure the amount of data flow. 1 e1 refers to 2mbps speed of data flow.

How will you convert weight of a garment of 200 GSM to 220 GSM?

Add 20 grams per square metre of the fabric. This could be in the form of embroidery, for example.

What is difference in CDMA and gsm?

Basically, the difference lie in the technology used. These two run on different frequencies and use different technologies which are not compatible with each other.

How many oz is 160 gsm?

160 GSM is about 4.72 ounces. So, if flannel sheets are listed at160 GSM, then the manufacturer may round up the number to say it'sabout 5 oz flannel weight.

Why GSM has to be Encrypted?

encyption prevents unauthorized access to the data that is transferred, that is the speech, or sms and so on

How is synchronization achieved in gsm?

A BSS has to generate the frame structure, which starts and ends with a tail field, and which has a training sequence in the mid. This fields can be used for synchronization. Each mobile device is doing its own synchronization due to this field, which is important because of time multiplexing to avoid overlapping data transmission, but BSS also has an important task to do in the synchronization: to make guard times small, it measures the distance to each end of device and calculates timing advances.

What is GSM in kraft paper?

GSM in relation to paper - is the weight in Grammes of one Square Metre. For example - 'regular' A4 copier paper is usually 70 GSM. Craft paper such as origami paper (for folding into models) is usually much lighter at around 40 GSM, or sheets of card is normally 120 GSM

What do you mean by Antenna Hopping in GSM?

Antenna hopping is a feature in which the Tx/Rx is passed through all the available antenna paths in a sector. No frequency is changed during antenna hopping. This helps improve performance by providing spatial diversity.

What modulation scheme is used in GSM?

GSM uses GMSK modulation scheme. GPRS also uses GMSK modulation scheme. EDGE and UMTS uses 8-PSK.

Why is a rectifier needed for a GSM BTS?

This is bcoz we need -48V for Gsm BTS, -48 DC is used to control Fluctuation So the main function of this is 1) To convert AC to DC 2) To control overloading

How do you check GSM in Kraft Paper?

cut 10x10 cm paper then check the weight of paper on gram. GSM is (weight of paper (W) divide by 0.01)

Why soft handoff is not used in GSM?

Because i thing in GSM no active set update measurement or no data for active cell or neighboring information before handover.

What is DTAP in gsm protocol?

There are 2 protocols by which CS core network can handle BSS on application layer viz. BSSap and DTAP DTAP is used when there is a direct transfer of signalling needed between Mobile Station MS and the CS Core network such as ciphering ans=d authentication.

What is gsm in tarpaulin is 7903?

gsm in tarpaulin means grams per square meter it refers to the quality of material used in production

Why gsm 900 better coverage than gsm 1800?

Because the power for the sector (Cell) is same the distace coverager nearly equal to power divide to frequency.

How is synchronization achieved in gsm who is responsible for synchronization and why it is so important?

A BSS has to generate the frame structure, which starts and ends with a tail field, and which has a training sequence in the mid. These fields can be used for synchronization. Each mobile device is doing its own synchronization due to these fields - which is important because of the time multiplexing to avoid overlapping data transmissions. But also the BSS has an important task in the synchronization: to make the guard times small, it measures the distance to each end device and calculates timing advances.

Formula for gsm of paper?

GSM is a gram per square meter . tempate of 20x25cm paper size cut it and weight it in weightometer

Which is thicker 130 gsm or 100 gsm?

In the context of Mobile phones gsm means Global System for Mobiles. Hoerver 100 gsm or 130 gsm is usually referred for thickness of paper. gsm means grammes per square meter. Hence 130 gsm is thicker than 100 gsm. Simple.

How do you remove SD Drop in GSM?

GSM Radio Frequency Optimization (GSM RFOptimization) is the optimization of GSM radio frequencies . GSM network consist of different cells and each celltransmit signals to and receive signals from the mobile station,for proper working of base station many parameters are definedbefore functioning the base station such as the coverage area of acell depends on different factors including the transmitting powerof the base station, obstructing buildings in cells, height of thebase station and location of base station. Radio Frequency Optimization is aprocess through which different soft ( Cell ReselectOffset , BTS power) andhard (e.g. Electrical Tilt , Mechanical Tilt , Azimuth etc.) parameters of the Basetransceiver stations are changed in order to improve thecoverage area and improve quality of signal. Besides that there arevarious key performanceindicators which have to be constantly monitored and necessarychanges proposed in order to keep KPIs in agreed limits with themobile operator. . Contents . 1 Introduction 2 Technical Details 2.1 GSM Call Flow 2.2 Key PerformanceIndicators 2.2.1 Paging SuccessRate 2.2.2 Immediate AssignmentSuccess Rate 2.2.3 Random Access SuccessRate 2.2.4 SDCCH DropRate 2.2.5 TCH Assignment SuccessRate 2.2.6 Call DropRate 2.2.7 Handover SuccessRate 3 Optimization Process 3.1 ProblemAnalysis 3.2 Checks Prior toAction 3.3 Drive Testing 3.4 Subjects toInvestigate 3.5 After the Test 3.6Recommendations 4 External links . Introduction . Optimization is an important step in the life cycle of awireless network. Drive testing is thefirst step in the process, with the goal of collecting measurementdata as a function of location. Once the data has been collectedover the desired RF coverage area, it is output to post-processingsoftware. Engineers can use the collection and post-processingsoftware to identify the causes of RF coverage or interferenceproblems and determine how these problems can be solved. When theproblems, causes and solutions have been identified, steps areperformed to solve the problems. Network statistics are also animportant step in analysis and troubleshooting of RF issues. Everynode (BTS, BSC, MSC) has its own counters some of which areincremented/decremented on occurrence of different events e.g. adropped call due to low signal strength. These statistics areanalysed using different graphs and reports and when KPI from the statisticsexceed the limit, extensive analysis is carried out to identify andtroubleshoot the problem. Technical Details GSM Call Flow . There are various controlchannels involved in setting up of a voice call in a GSMnetwork. On Broadcast Channels system information and various parameters along withsynchronization and frequency correction information istransmitted. Common Control Channels are used for informing the mobile or the GSM network about aservice(voice, data, SMS) initiation and Dedicated Control Channels are used for callsetup, authentication, location updating and SMS. A mobile isinformed on a paging channel(PCH) that it has a call or SMS, to which the mobile station respondswith a Random Access Channel (RACH) request. The mobile station is notified on an Access Grant Channel (AGCH) that it may tuneto a specific Stand-alone dedicatedcontrol channel (SDCCH) which is called Immediate Assignment.The user is authenticated and ciphering commands are received onthis channel. After successful authentication the mobile station isrequested to tune to an assigned traffic channel(TCH). This processis called TCH assignment. Then the user starts to move from onecell to another and the process of smooth transitioning of callfrom one cell to the other is called a handover . While on the SDCCH or TCH a call may getdropped which is accounted to SDCCH drop or TCH droprespectively. Key Performance Indicators Paging Success Rate . Paging Success by far is the most complex KPI to deal with asthe process of paging touches almost all the nodes in GSM systemand is influenced by performance of each of them. That's the reasonwhy this write up on paging looks too interwoven and cross refersto too many things. But the plus point with paging is by the timepaging success rate in a network gets improved; almost all theother KPIs too stand improved. In response to an incoming call, theMSC initiates the paging process by broadcasting a "paging request"message on the paging sub channel (IMSI or TMSI of the MS and itsPaging Group) and starts timer T3113. A "paging message" consistsof the mobile identity (IMSI or TMSI) of the MS being paged and its"paging group number". A Paging Request Message may include morethan one MS identification. The maximum number of paged MS permessage is 4 when using "TMSI" for identification of the MS(maximum number of paged MS per message is 2 when using IMSI). TheBSC receives this page and processes the paging request andschedules it for transmission on the PCH at appropriate time. TheMS on its part will analyse the paging messages (and immediateassignment messages) sent on the paging sub channel correspondingto its paging group. Upon receipt of a "paging request" message, MSwill initiate within 0.7s an immediate assignment procedure. Uponreceipt of a page at the MS, the MS responds by transmitting achannel request on the RACH. BSS in response to the received"channel request", will process it and immediately assign the MS aSDCCH (immediate assignment / assignment reject; done over AGCH).MS Paging response- After receiving the immediate assignmentcommand, MS switches to the assigned "SDCCH" and transmits a"Paging Response". The establishment of the main signalling link isthen initiated with information field containing the "PAGINGRESPONSE" message and the "paging response" is sent to the MSC.Upon receipt of the "Paging Response" MSC stops the timer T3113. Ifthe timer T3113 expires and a "Paging Response"message has not beenreceived, the MSC may repeat the "Paging Request" message and startT3113 all over again. The number of successive paging attempt is anetwork dependent choice. . One control channel Multi Frame is made of 51 TDMA frames with atime duration of 235 ms. Each 51 TDMA frame Multi Frame will have 9Common Control Channel (CCCH) blocks. Each of these 9 CCCH block ismade of 4 TDMA frames. Each CCCH block can carry Paging Messagesfor 2 MS if IMSI based paging is used or 4 MS if TMSI based pagingis used. Thus the paging capacity for one 51 TDMA frame Multi Framewill be 9(number of CCCH blocks available per Multi Frame) * 4(when TMSI based paging is used) = 36 mobiles per 235 ms or 9*2 =18 mobiles per 235 ms when IMSI based paging is used. Thus thepaging capacity of a cell is 153 mobiles per second when TMSI basedpaging are used and 68 mobiles per second when IMSI based pagingare used. This means we can improve the "paging bandwidth" for acell (if there are too many "paging discards at the cell level") byusing TMSI based paging rather than IMSI based (at the expense ofincreased processor load at the BSC and MSC). When the rate of"paging load" at the BTS becomes higher than what the BTS is ableto handle (paging capacity of BTS), BTS will start discarding pages(check for high "page discard" stats at the cell level). Once an MSdeciphers its paging group, in an idle mode, it will tune in andcheck for an incoming page only during broadcast time for itspaging group (so further the paging groups are places acrossmultiple 51 frame multi frames, less frequently it will tune in tocheck for an incoming page and longer will be its battery life. Butthe problem in this case for a cell with high paging load is Immediate Assignment Success Rate . T1313 Random Access Success Rate . Random Access Channel (RACH) is used by the MS on the "uplink"to request for allocation of an SDCCH. This request from the MS onthe uplink could either be as a page response (MS being paged bythe BSS in response to an incoming call) or due to user trying toaccess the network to establish a call. Availability of SDCCH atthe BTS will not have any impact on the Random Access Success. Inthe transceiver, the timeslot handler in charge of the RACH channellistens for access burst from mobiles (on the time-slot thattransmits BCCH). These bursts contain a check sequence (8 bits)that is used to determine if the message is valid. SDCCH Drop Rate TCH Assignment Success Rate . TCH assignment failure is a phenomenon where the MS is not ableto use the TCH which is assigned to it for voice call.This couldhappen due to uplink /downlink interference, faulty radio or faultyantenna system. Call Drop Rate . TCH drop (or a dropped call) could be broadly classified into 3sub classes: . Degradation of the links (Uplink and Downlink): eitherdegradation of Signal Strength which falls near or lower than thesensitivity of the base station (around to -110 dBm) or that of themobile (around -104dBm) or degradation of quality of the links(Uplink and Downlink) often due to interference. . Excess TA (TA>63 or excess path imbalance due to highTA). . Other Reasons. Handover Success Rate . Handover in BSS system is controlled an algorithm in the BSC.This algorithm operates on the basis of Measurement Reports (MR)sent in by the MS on SACCH . Theinputs that the BSC uses for making a handover decision, from thereceived MRs from the MS is the DL signal strength, DL quality, andthe signal strength of the six best reported neighbours. From theserving BTS, for the same MS the BSC will use UL signal strength,UL quality and TA. Optimization Process . Optimization process can be explained by below step by stepdescription: Problem Analysis . Analyzing performance retrieve tool reports and statistics forthe worst performing BSCs and/or Sites . Viewing Reports for BSC/Site performance trends . Examining Planning tool Coverage predictions . Analyzing previous drive test data . Discussions with local engineers to prioritize problems . Checking Customer Complaints reported to local engineers Checks Prior to Action . Cluster definitions by investigating BSC borders, main cities,freeways, major roads . Investigating customer distribution, customer habits(voice/data usage) . Running specific traces on Network to categorize problems . Checking trouble ticket history for previous problems . Checking any fault reports to limit possible hardware problemsprior to test Drive Testing . Preparing Action Plan Defining drive test routes . Collecting RSSI Log files . Scanning frequency spectrum for possible interferencesources . Re-driving questionable data Subjects to Investigate . Non-working sites/sectors or TRXs . In-active Radio network features like frequency hopping . Disabled GPRS . Overshooting sites - coverage overlaps . Coverage holes . C/I , C/A analysis . High Interference Spots . Drop Calls . Capacity Problems . Other Interference Sources . Missing Neighbors . One-way neighbors . Ping-Pong Handovers . Not happening handovers . Accessibility and Retain-ability of the Network . Equipment Performance . Faulty Installations After the Test . Post processing of data Plotting RX Level and QualityInformation for overall picture of the driven area . Initial Discussions on drive test with Local engineers . Reporting urgent problems for immediate action . Analyzing Network feature performance after newimplementations . Transferring comments on parameter implementations after newchanges Recommendations . Defining missing neighbor relations . Proposing new sites or sector additions with Before & Aftercoverage plots . Proposing antenna azimuth changes . Proposing antenna tilt changes . Proposing antenna type changes . BTS Equipment/Filter change . Re-tuning of interfered frequencies . BSIC changes . AdjustingHandover margins (Power Budget, Level, Quality,Umbrella HOs) . Adjusting accessibility parameters (RX Lev Acc Min, etc..) . Changing power parameters . Attenuation Adds/Removals . MHA/ TMA adds

How do you make GSM?

GSM is a way to communicate between a computer and a GSM-GPRS system. This is used mobile communication in most countries it enables higher data transmission rate.

What unlocked phones work on gsm?

So basically it has to have gsm radio, because there are two radios cdma and gsm, gsm works with all gsm carriers And cdma only works with on cdma carriers So if your looking for unlocked gsm for gsm service, look up device before buying