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Worldwide localization of users and roaming are the main service provided by the GSM network system. The system always knows where a user currently is, and the same phone number is valid worldwide. For providing this service GSM updates the user LOCATION periodically. The HLR always CONTAINS information about the current location. VLR responsible for the MS informs the HLR about location changes. As soon as an MS moves into the new location area (range of new VLR), the HLR sends all user information needed to the new VLR.

To locate an MS and to address the MS, following NUMBERS are needed:

• Mobile station international ISDN number (MSISDN). 
• International mobile SUBSCRIBER identity (IMSI). 
• Temporary mobile subscriber identity (TMSI). 
• Mobile station7 roaming number (MSRN).

Worldwide localization of users and roaming are the main service provided by the GSM network system. The system always knows where a user currently is, and the same phone number is valid worldwide. For providing this service GSM updates the user location periodically. The HLR always contains information about the current location. VLR responsible for the MS informs the HLR about location changes. As soon as an MS moves into the new location area (range of new VLR), the HLR sends all user information needed to the new VLR.

To locate an MS and to address the MS, following numbers are needed:

• ACCESS point control FUNCTION
• Call control and CONNECTION control function
• Network security agent
• Service control function
• Mobility MANAGEMENT function

EVEN if the LOCATION of a terminal is known to the system, it still has to route the traffic through the network to the access POINT currently responsible for the wireless terminal. Each time a USER moves to a new access point, the system must reroute traffic. This is known as mobile routing.

Even if the location of a terminal is known to the system, it still has to route the traffic through the network to the access point currently responsible for the wireless terminal. Each time a user moves to a new access point, the system must reroute traffic. This is known as mobile routing.

Moving between access point is called roaming. Even wireless NETWORKS may REQUIRE more than one access point to cover all rooms. In order to provide uninterrupted SERVICE, we require roaming when the user MOVES from one access point to ANOTHER.

Moving between access point is called roaming. Even wireless networks may require more than one access point to cover all rooms. In order to provide uninterrupted service, we require roaming when the user moves from one access point to another.

• Synchronization
• Power management
• Roaming
• Management INFORMATION BASE (MIB)

Advantages:

1. SIMPLE and extremely cheap SENDERS and receivers which integrated in almost all mobile devices
2. No licenses are needed for infrared technology and shielding is very simple.
3. Electrical devices do not interfere with infrared transmission.

Disadvantages:

1. LOW BANDWIDTH
2. Quite easily shielded
3. Cannot Penetrate

Advantages:

Disadvantages:

1. PRIORITIZATION: Determine the highest priority of a data packet READY to be SENT on competing nodes.
2. CONTENTION: Eliminate all but one of the contenders, if more than one sender hasthe highest CURRENT priority.
3. Transmission: Finally, transmit the packet of the remaining node.

SCO-stands for Synchronous Connection Oriented Link STANDARD telephone (voice) connection require symmetrical, circuit-switched, point-to-point CONNECTIONS. For this type of link, the master reserves TWO consecutive SLOTS at fixed INTERVALS.

SCO-stands for Synchronous Connection Oriented Link Standard telephone (voice) connection require symmetrical, circuit-switched, point-to-point connections. For this type of link, the master reserves two consecutive slots at fixed intervals.

• PARK STATE
• HOLD state
• SNIFF state

• Global Operation
• Low Power
• License-free Operation
• Robust transmission TECHNOLOGY
• SIMPLIFIED spontaneous co-operation
• Easy to USE
• protection of investment
• Safety and Security
• TRANSPARENCY for application

• Flexibility,
• Planning,
• DESIGN,
• Robustness,
• QUALITY Service,
• Cost,
• PROPRIETARY Solution,
• Restriction,
• SAFETY and SECURITY

SIFS MEANS Short Inter FRAME Spacing. The SHORTEST waiting time defined for short control MESSAGE such as ACKNOWLEDGEMENTS or polling response.

SIFS means Short Inter Frame Spacing. The shortest waiting time defined for short control message such as acknowledgements or polling response.

The primary goal of the standard was the specification of a simple, robust, WLAN which offers time BOUNDED and asynchronous SERVICES also it should be able to operate with multiple PHYSICAL layers.

The primary goal of the standard was the specification of a simple, robust, WLAN which offers time bounded and asynchronous services also it should be able to operate with multiple physical layers.

Passive Scanning SIMPLY MEANS listening into the medium to find other networks, i.e. receiving the beacon of another NETWORK ISSUED by the synchronization function within an access point.

Passive Scanning Simply means listening into the medium to find other networks, i.e. receiving the beacon of another network issued by the synchronization function within an access point.

ACTIVE scanning comprises sending a PROBE on each CHANNEL and waiting for response. Beacon and Probe response contain the INFORMATION necessary to JOIN the new BSS.

Active scanning comprises sending a probe on each channel and waiting for response. Beacon and Probe response contain the information necessary to join the new BSS.

A BEACON contains a timestamp and other management INFORMATION used for power management and roaming. e.g., identification of the base station SUBSYSTEM (BSS).

A beacon contains a timestamp and other management information used for power management and roaming. e.g., identification of the base station subsystem (BSS).

1. Data rates planned for users are 6-38mbit/s for the downlink and 33-100kbit/s for the uplink.
2. Transmitted along with TV programmes and doesn’t REQUIRE ADDITIONAL lines or hardware per customer.
3. Can be USED in remote areas and developing COUNTRIES where there is no high band width wired network.

Digital Video Broadcast Containers are basically MPEG-2 FRAMES. DVB sends service information. This information is, 

1. Network information table(NIT).
2. Service Description Table(SDT).
3. Event Information Table(EIT).
4. TIME and Date Table(TDT)

Digital Video Broadcast Containers are basically MPEG-2 frames. DVB sends service information. This information is, 

EVENT INFORMATION Table (EIT) contains STATUS information about the CURRENT transmission and some additional information for set-top boxes.

Event Information Table (EIT) contains status information about the current transmission and some additional information for set-top boxes.

DAB can repeat objects several times. If an OBJECT A consists of FOUR segments (A1, A2, A3, A4) a single repetition pattern WOULD be A1A2A3A4A1A2A3A4A1A2A3A4……..

DAB can repeat objects several times. If an object A consists of four segments (A1, A2, A3, A4) a single repetition pattern would be A1A2A3A4A1A2A3A4A1A2A3A4……..

1. DAB can offer sound in CD like quality.
2. DAB can use single FREQUENCY network where all senders transmitting the same radio program can operate at the same frequency.
3. DAB use VHF and UHF frequency bands.
4. DAB uses DQPSK modulation SCHEME.
5. DAB user COFDM and FEC.
6. DAB can TRANSMIT up to six stereo audio programmes with a data rate of 192kbit/s each.

1. OBJECT Repetition.
2. INTERLEAVED Objects.
3. Segment repetition.
4. HEADER repetition.

• Multimedia and Hypermedia information coding experts group(MHEG)
• Join photograph’s experts group(JPEG)
• American STANDARD code for information INTERCHANGE(ASCII)
• Moving pictures expert group(MPEG)
• HYPERTEXT markup language(HTML)
• Hypertext transfer protocol(HTTP)
• Bitmap(BMP)
• Graphics interchange format(GIF)

The goal of DVB is to introduce digital TV BROADCASTING USING satellite TRANSMISSION (DVB-5) cable technology (DVB-c) and TERRESTRIAL transmission (DVB-7).

The goal of DVB is to introduce digital TV broadcasting using satellite transmission (DVB-5) cable technology (DVB-c) and terrestrial transmission (DVB-7).

• A FLAT DISKS
• SKEWED disks
• MULTI disks

The Fast Information Channel(FIC) CONTAINS Fast Information Block(FIB) with 256bits each(16 bit checksum). An FIC carries all control information which is required for INTERPRETING the configuration and CONTENT of the MSC.

The Fast Information Channel(FIC) contains Fast Information Block(FIB) with 256bits each(16 bit checksum). An FIC carries all control information which is required for interpreting the configuration and content of the MSC.

MAIN Service CHANNEL(MSC) carries all USER DATA. eg. Audio, multimedia data.

Main Service Channel(MSC) carries all user data. eg. Audio, multimedia data.

Seven BYTES field contains the sizes of the header and the body, the content type of the OBJECT. Depending on this header information, the RECEIVER may decide if it has enough resources(MEMORY, cpu, POWER, display etc) available to decode and further process the object.

Seven bytes field contains the sizes of the header and the body, the content type of the object. Depending on this header information, the receiver may decide if it has enough resources(memory, cpu, power, display etc) available to decode and further process the object.

The elevation ANGLE is DEFINED as the angle between the centre of satellite beam and the PLANE tangential to the EARTH’s surface. The foot-print can be defined as the area on earth where the signals of the satellite can be received.

The elevation angle is defined as the angle between the centre of satellite beam and the plane tangential to the earth’s surface. The foot-print can be defined as the area on earth where the signals of the satellite can be received.

The inclination angle is defined as the angle between the EQUATORIAL plane and the plane described by the SATELLITE ORBIT. An inclination angle of 0 degrees means that the satellite is EXACTLY above the EQUATOR. If the satellite does not have a circular orbit, the closest point to the earth is called the perigee.

The inclination angle is defined as the angle between the equatorial plane and the plane described by the satellite orbit. An inclination angle of 0 degrees means that the satellite is exactly above the equator. If the satellite does not have a circular orbit, the closest point to the earth is called the perigee.

• Data RATE is 2400 bit/s
• Packet DELAY is relatively LOW
• Smaller footprints of LEO ALLOWS frequency reuse
• Provide HIGH elevations

• WEATHER forecasting SATELLITES
• Radio & TV broadcast satellites
• Military satellites
• Satellites for NAVIGATION
• Mobile communication

Satellites can be USED in the FOLLOWING AREAS

• Weather Forecasting
• Radio and TV broadcast Satellites
• Military Satellites
• Satellites for Navigation

Satellites can be used in the Following Areas

USING Orbits around 10,000Km, the system only requires a dozen SATELLITES which is more than the GEO system, but much less than a LEO system. Further more these satellites move slower relative to the earth’s rotation ALLOWING a SIMPLER system design. Depending on the inclination a MEO can cover larger populations, thus requiring lesshandovers.

Using Orbits around 10,000Km, the system only requires a dozen satellites which is more than the GEO system, but much less than a LEO system. Further more these satellites move slower relative to the earth’s rotation allowing a simpler system design. Depending on the inclination a MEO can cover larger populations, thus requiring lesshandovers.

1. Home Location Register (HLR).
2. VISITOR Location Register (VLR).
3. SATELLITE USER MAPPING Register (SUMR).

The SATELLITE is the base station in satellite communication systems and that it self is moving. So, ADDITIONAL INSTANCE of handover are necessary due to the movement of the satellite

1. Intra Satellite handover:
2. Inter Satellite handover.
3. GATEWAY handover.
4. Inter System handover.

The satellite is the base station in satellite communication systems and that it self is moving. So, additional instance of handover are necessary due to the movement of the satellite

Three GEO SATELLITES are enough for a complete coverage of ALMOST any SPOT on earth, senders and receivers can use fixed ANTENNAS positions, and no adjusting is needed. THEREFORE GEO’s are ideal for T.V and radio broadcasting.

Three GEO satellites are enough for a complete coverage of almost any spot on earth, senders and receivers can use fixed antennas positions, and no adjusting is needed. Therefore GEO’s are ideal for T.V and radio broadcasting.

GEO MEANS Geostationary or Geosynchronous earth orbit. GEO satellites have a DISTANCE of almost 36000 km to the earth. Examples are almost all TV and RADIO BROADCAST satellites, many WEATHER satellites and satellites operating as backbone for the telephone network.

GEO means Geostationary or Geosynchronous earth orbit. GEO satellites have a distance of almost 36000 km to the earth. Examples are almost all TV and radio broadcast satellites, many weather satellites and satellites operating as backbone for the telephone network.

The function of Medium Access CONTROL Layer is responsible for establishes, MAINTAINS, and releases channels for higher LAYERS by ACTIVATING and DEACTIVATING physical channels.

The function of Medium Access Control Layer is responsible for establishes, maintains, and releases channels for higher layers by activating and deactivating physical channels.

• TRAFFIC CHANNEL (TCH)
• CONTROL channel (CCH)

The FRAME USED for normal data TRANSMISSION within a TIME slot is CALLED Normal Burst.

The frame used for normal data transmission within a time slot is called Normal Burst.

• CARD TYPE, SERIAL no, list of subscribed services
• Personal Identity Number (PIN)
• Pin UNLOCKING Key (PUK)
• An Authentication Key (KI)

• Radio subsystem (RSS)
• NETWORK & Switching subsystem(NSS)
• OPERATION subsystem(OSS)

The General Packet Radio Service PROVIDES packet mode TRANSFER for applications that EXHIBIT TRAFFIC patterns such as frequent transmission of small volumes.

The General Packet Radio Service provides packet mode transfer for applications that exhibit traffic patterns such as frequent transmission of small volumes.

• INTRA-cell HANDOVER
• INTER-cell ,intra- BSC handover
• Inter-BSC, intra-MSC handover
• Inter MSC handover

• USER identification
• CALL REDIRECTION
• Call forwarding
• Closed user GROUPS
• MULTIPARTY Communication

• BEARER SERVICES
• TELE services
• SUPPLEMENTARY services

TETRA (TERRESTRIAL Trunked Radio) systems use different radio CARRIER frequencies, but they ASSIGN a specific carrier frequencies for a short period of time ACCORDING to demand. 

TETRA (Terrestrial Trunked Radio) systems use different radio carrier frequencies, but they assign a specific carrier frequencies for a short period of time according to demand. 

1. INTRA CELL Handover
2. Inter cell Intra BSC Handover
3. Inter BSC Intra MSC handover
4. Inter MSC Handover

Polling is a strictly centralized scheme with one master and several slave STATIONS. The master can collect the LIST of stations during the contention phase and can poll these slaves according to MANY schemes like round robin, random access, RESERVATION scheme ETC.

Polling is a strictly centralized scheme with one master and several slave stations. The master can collect the list of stations during the contention phase and can poll these slaves according to many schemes like round robin, random access, reservation scheme etc.