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by Shri

GSM: Physical & logical Channels

Aug 1, 2011 at 9:21 am in GSM by Shri · 1 Comment »

Multiframes-in-GSM

GSM: PHYSICAL AND LOGICAL CHANNELS

GSM uses a mix of Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA). FDMA parts involves the division by frequency of the 25 MHz bandwidth in to 124 carrier frequencies (Also called ARFCN) spaced 200 KHz for GSM-900. For GSM-1800 frequency spectrum of 75 MHz bandwidth is divided in to 374 carrier frequencies spaced 200 KHz. TDMA further divides each carrier frequencies in to 8 time slots such that each carrier frequency is  [read more →]

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by karthik

International Mobile Subscriber Identity (IMSI)

Oct 24, 2010 at 12:23 pm in GSM by karthik · 1 Comment »

International Mobile Subscriber Identity (IMSI)

       The subscriber is identified by an identity number called the International Mobile Subscriber Identity (IMSI).This number identifies the MS(Mobile Station) subscriber.

The International Mobile Subscriber Identity(IMSI) is embodied in the SIM of the mobile equipment. It is provided by the MS anytime it accesses the network.It is only transmitted over the air during initialization.

Since the air interface is vulnerable to fraudulent access, it is necessary to determine if  [read more →]

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by LT contributor

Basics of Steering of Roaming

Oct 18, 2010 at 10:21 pm in GSM by LT contributor · 3 Comments »

Steering-of-Roaming

Why SoR Required?

Roaming contributes a substantial portion of a mobile operator’s revenue. Typically, a home network has very little control over the selection of networks for out-roamers. Many out-roamers continue to register on visited networks which are not preferred by HPLMN, making it difficult to control roaming costs and ensure quality of service.

A picture will speak 1000 words; I hope you understood the problem.

So, HPLMN required some sort of legal and technical solution which solves their problem and providing  [read more →]

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by LT contributor

GSM Vs CDMA

Aug 19, 2010 at 11:38 pm in GSM by LT contributor · Leave a Comment »

In technology circles, it has long been known that CDMA beats the pants off GSM. It is, to state it in no uncertain terms, the technology of the future. Event 3G GSM networks will use CDMA based technologies.

Why CDMA is best?

  • Its Faster.
  • Its more secure.
  • Connection on a CDMA network will never get dropped when moving from cell to cell.
  • CDMA base-station covers a larger area.

Why GSM is preferred?

CDMA standard is patented  [read more →]

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by LT contributor

Subscriber Identity Module

Jul 28, 2010 at 12:08 am in GSM by LT contributor · 2 Comments »

A subscriber identity module (SIM) on a removable SIM card securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony devices (such as mobile phones and computers). The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device.

-Wikipedia

The Subscriber Identity Module (SIM) is a small smart card which contains both  [read more →]

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by LT contributor

Learn about SMS Hubbing

Jul 22, 2010 at 10:27 pm in GSM by LT contributor · 3 Comments »

Hubbing SMS Call Flow

Why SMS Hubbing?

Every operator has the need to establish roaming agreements in order to provide subscribers with the possibility to roam outside their home network. The overall cost of establishing bi-lateral relationships is preventing some operators from opening new roaming and Inter-working agreements. With the introduction of more new services the problem will become more evident and the overall costs greater. This is a particular concern for the newer GSM networks, those networks that are late entries into the  [read more →]

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by Shri

SMS in GSM Network

Jul 19, 2010 at 9:45 am in GSM by Shri · 56 Comments »

# SMS (Short Message Service) is the transmission of short text messages to and from a mobile phone, or any other device capable of generating the SMS. It is composed of a maximum of 160 characters, each coded on 7 bits (GSM) or 140 bytes.
# End to end SMS delivery completes in two parts, First SMS submission in SMSC (Short Message Service Centre) by originating subscriber, second Delivery of SMS to recipient subscriber. So SMS is a Stored and Forward Service.

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by LT contributor

Go Green Telecom

Jul 6, 2010 at 10:27 pm in GSM by LT contributor · Leave a Comment »

This not to scare you at the first instance. A plain logical calculation which is something of botheration here. There are 5,773,000 cubic miles of water in ice caps, glaciers, and permanent snow. According to the National Snow and Ice Data Center, if all glaciers melted today the sea would rise about 230 feet. Luckily, that’s not going to happen all in one go! But sea levels will rise. Sorry if you feel threatened but avoiding this is not our responsibility or  [read more →]

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by Shri

SMS FRAUD

Jun 27, 2010 at 5:50 pm in GSM by Shri · 12 Comments »

SMS Fraud

SMS Fraud is growing rapidly and is becoming a significant issue for all GSM Operators. Nowadays GSM operators are facing numbers of issues related to SMS problem such as Spamming, Spoofing, Fake SMS and illegal use of SMSC Address. Fraud SMS cause :

  • Revenue leakage due to faked SMS traffic and SMS spoofing.
  • Unpredictable loads on the network due to SMS flooding.
  • Increasing Complaint from Mobile subscriber due to SMS Spamming.

Please register to download this file. Its Free  Basics of  [read more →]