mobile apps testing tele communication doc

www.h2kinfosys.comEmail: [email protected]: 770-777-1269 UK: 020 33717615

Introduction to telecommunication Telecommunication - Communication at distance through signals of varied nature coming from a transmitted to receiver Signals:

Lights, Sounds , but not in secured, no fast information Electro magnetic energy, is able to transport information in an extremely fast way In 1809, Thomas S. Sommering proposed a telegraphic system composed of a battery, 35 wires (one foreach letter and number) and a group of sensors made of gold, which were submerged in a water tank: when asignal was passing from one of those wires, electrical current would split water molecules, and small oxygenbubbles would be visible near that sensor1843, the year in which Samuel Morse proposed a way to assign each letter and number to a ternary code(point, line, and space). This way turned out to be extremely convenient and more affordable thanSommering’s idea, especially in terms of reduced circuitry (you wouldn’t need anymore a wire for eachsymbol). Meanwhile, technology became advanced enough to find a way to convert those signals in audible(or sometimes graphic) signals. The combination of these two factors quickly determined the success ofMorse’s symbol code, which we can still find used todaySeven years later, Antonio Meucci and Graham Bell independently managed to build a prototype of an earlytelephone (’sound at distance’) machine. Since Meucci didn’t have the money to patent his invention (the costwas $250 at the time), Bell managed to register it first.Both with telegraphs and telephones, the need for a distributed and reliable communication network soonbecame evident. Routing issues were first solved by means of human operators and circuit commutation: thePSTN (Public Switched Telephone Network) was born. However, this system didn’t guarantee the privacy andsecrecy of conversations, and efforts towards the development of an automatic circuit commutation weremade.

www.h2kinfosys.com Email: [email protected] USA: 770-777-1269 UK: 020 33717615

Evolution of GSM: (Global System for Mobile communication)

GSM (2G) GPRS (General Packet Radio Service) (2.5 G) - data speeds of up to 171.2 Kbps EDGE (Enhanced Data rate for GSM Evolution) (2.5 G) - data rates to 384 Kbpsif/when deployedHigh Speed Circuit Switched Data (HSCSD) (2.5 G) - speeds of up to 64 Kbps. However, HSCSD perpetuates the inefficient use of spectrum and transmission that is relegated by any circuit switched mechanism 3G (CDMA 2000) - provide up to 2 Mbps

Long Term Evolution( 4G)

GSM history In 1982, the E u r o p e a n C o n f ere nc e of P o s t a l a n d T e l ec o m mu n i c a t i o n s Ad m in i s t r a t i o n s (C E P T ) created the G r o u p e S p é c i a l M ob i le (GSM) to develop a standard for a mobile telephone system that could be used across

Europe.[6] In 1987, a m e m o r a n d u m of un d er s t a n d i n g was signed by 13 countries to develop a commoncellular telephone system across Europe.n 1989, GSM responsibility was transferred to the E u r o p e a n T e l ec o m mu n i c a t i o n s St a n d a r d s I n s t i t u te (ETSI) and phase I of the GSM specifications were published in 1990.The first GSM network was launched in 1991 by R a d i o l in j a in F i n l a n d with joint technicalinfrastructure maintenance from E ri c ss o n .By the end of 1993, over a million subscribers were using GSM phone networks being operated by 70 carriers across 48 countries.

GSM Standards ETSI 3GPP

Reference:h tt p:// ww w . mo b i le i n . c om / g s m _s t a n d a r d s . h tm h tt p: // w w w . e t s i . o r g / W e b S i t e / h o m e p a g e . a s p x www.3gpp.org/

Electro Magnetic Spectrum

GSM

900 GS

M1800 GS

M1900 GS

M450

GSM

480 GS

M850

GSM


GSM Frequency Bands

Cellular concepts

The basic unit of GSM radio coverage is known as a cell. Cell is the area covered by single transmitter

Types of Cells

•Macro cells•<35 KMS•Antenna above the roofs

•Micro cells•Antenna below the roofs

•Pico cells•Very small coverage

•Extended Cells•Radius of maximum 120 kms•Coastal region


• Cluster

• Frequency reuse pattern

• Cell capacity expansion techniques

•Cell splitting•Cell sectoring•Frequency allocation•Multiple access techniques

•FDMA•TDMA

•CDMA

Uplink and Downlink

Circuit switched Vs Packet Switched

MS BTS BSC MSC

GSM


GSM Interfaces


MS :

The MS consists of the physical equipment used by the subscriber to access a PLMN for offered telecommunication services. Functionally,the MS includes a Mobile Termination (MT) and, depending on the services it can support, various Terminal Equipment (TE), and combinations of TE and Terminal Adaptor (TA) functions (the TA acts as a gateway between the TE and the MT) (see Figure 5.4). Various types of MS, such as the vehiclemounted station, portable station, or handheld station, are used.

An MS has a number of identities including the International Mobile Equipment Identity (IMEI), the International Mobile Subscriber Identity (IMSI), and the ISDN number. The IMSI is stored in the SIM. The SIM card contains all the subscriber-related information stored on the user’s side of the radio interface.

IMSI. The IMSI is assigned to an MS at subscription time. It uniquely identifies a given MS. The IMSI will be transmitted over the radio interface only if necessary. The IMSI contains 15 digits and includes

• Mobile Country Code (MCC)—3 digits (home country)• Mobile Network Code (MNC)—2 digits (home GSM PLMN)• Mobile Subscriber Identification (MSIN)• National Mobile Subscriber Identity (NMSI)

IMEI:The IMEI uniquely identifies the MS equipment. It is assigned by the equipment manufacturer. The IMEIcontains 15 digits and carries•The Type Approval Code (TAC)—6 digits•The Final Assembly Code (FAC)—2 digits•The serial number (SN)— 6 digits•A Spare (SP)—1 digit

BSS :

The BSS is the physical equipment that provides radio coverage to prescribed geographical areas, known as the cells. It contains equipment required to communicate with the MS. Functionally, a BSS consists of a control function carried out by the BSC and a transmitting function performed bythe BTS. The BTS is the radio transmission equipment and covers each cell. A BSS can serve several cellsbecause it can have multiple BTSs.

The BTS contains the Transcoder Rate Adapter Unit (TRAU). In TRAU, the GSM-specific speech encoding and decoding is carried out, as well as the rate adaptation function for data. In certain situations the TRAU is located at the MSC to gain an advantage of more compressed transmission between the BTS and the MSC.

NSS:

The NSS includes the main switching functions of GSM, databases required for the subscribers, and mobility management. Its main role is to manage the communications between GSM and other network users.Within the NSS, the switching functions are performed by the MSC. Subscriber information relevant toprovisioning of services is kept in the HLR.The other database in the NSS is the VLR.The MSC performs the necessary switching functions required for the MSs located in an associated geographical area, called an MSC area

GSM


GSM Interfaces

The Radio Interface (MS to BTS)

The Um radio interface (between MS and base transceiver stations [BTS]) is the most important in any mobileradio system, in that it addresses the demanding characteristics of the radio environment.

Abis Interface (BTS to BSC)

The interconnection between the BTS and the BSC is through a standard interface, Abis (most Abis interfaces are vendor specific). The primary functions carried over this interface are traffic channel transmission, terrestrial channel management, and radio channel management.

A Interface (BSC to MSC)

The A interface allows interconnection between the BSS radio base subsystemand the MSC. The physical layer of the A interface is a 2-Mbps standard ConsultativeCommittee on Telephone and Telegraph (CCITT) digital connection.

GSM


Signaling Protocols between GSM Entities


GSM GPRS Architecture


GSM

Components in GPRS

GPRS Mobile Stations:New Mobile Station are required to use GPRS services because existing GSM phones do not handle the enhanced air interface or packet data. A variety of MS can exist, including a high-speed version of current phones to support high-speed data access, a new PDA device with an embedded GSM phone, and PC cards for laptop computers. These mobile stations are backward compatible for making voice calls using GSM.

GPRS Base Station Subsystem:Each BSC requires the installation of one or more Packet Control Units (PCUs) and a software upgrade. The PCU provides a physical and logical data interface to the base station subsystem (BSS) for packet data traffic. The BTS can also require a software upgrade but typically does not require hardware enhancements.When either voice or data traffic is originated at the subscriber mobile, it is transported over the air interface to the BTS, and from the BTS to the BSC in the same way as a standard GSM call. However, at the output of the BSC, the traffic is separated; voice is sent to the mobile switching center (MSC) per standard GSM, and data is sent to a new device called the SGSN via the PCU over a Frame Relay interface.

GPRS Support Nodes:Following two new components, called GPRS support nodes (GSNs), are added:Gateway GPRS support node (GGSN):The Gateway GPRS Support Node acts as an interface and a router to external networks. The GGSN contains routing information for GPRS mobiles, which is used to tunnel packets through the IP based internal backbone to the correct Serving GPRS Support Node. The GGSN also collects charging information connected to the use of the external data networks and can act as a packet filter for incoming traffic. Serving GPRS support node (SGSN):The Serving GPRS Support Node is responsible for authentication of GPRS mobiles, registration of mobiles in the network, mobilitymanagement, and collecting information for charging for the use of the air interface.Internal Backbone:The internal backbone is an IP based network used to carry packets between different GSNs. Tunneling is used between SGSNs andGGSNs, so the internal backbone does not need any information about domains outside the GPRS network. Signaling from a GSN to a MSC, HLR or EIR is done using SS7.

mobile apps testing tele communication doc

Education

gspeedsof upto64

way in1809

isable totransportinformation

gsmhistory in1982

gpp reference

mbps longtermevolution4g

gsmstandards etsi