Types Of VSAT

VSAT IP

Data communications services that use satellite access media technology Time Division Multiplex (TDM) / Time Division Multiple Access (TDMA) based on standard Internet Protocol (IP).Topology IP VSAT system in the form of star with a hub and a remote system. Hub to communicate with a remote antenna using TDM channel while the remote antenna to send data to the hub using a TDMA channel.

Allotment :

VSAT IP according to the types of applications as follows:

Transactional and interactive applications

·         Online inter-branch

·         Reservation hotel / airfare

·         ATM (Automated Teller Machine)

·         Traffic data is small

Application of remote terminal / telnet / terminal emulation with a centralized data base

·         Data entry

·         Control of stock (inventory control)

·         Payment point

Internet Applications

·         Web surfing

·         E-mail

·         Instant messaging

File Transfer Protocol (FTP)

Features

·         Have a high level of security because it is a private network

·         Many choices of services in accordance with customer needs

·         IP VSAT service coverage to reach all parts of Indonesia

·         Many choices of access methods according to application needs of customers with broadband satellite technology with the IP protocol

·         Speeds to 20 Mbps with Ethernet LAN interface

·         Service Level Agreement of 99%

·         Service interruption complaints 24 hours a day, 7 days a week

Benefits

·         Economical, especially to the relationship some remote location outside the city

·         Flexibility in technology because it is easily linked with other Lintasarta services as an integrated solution

·         Flexibility in installation, especially for locations that are beyond the reach of cable or a location far from the central business districts

·         Reliable because it is supported by the operational 24 hours a day, 7 days a week

Technical Specifications

·         Using satellite broadband technology

·         QPSK modulation

·         Asimetric rate

-          Downstream: 1.2 - 20 Mbps

-          Upstream: 128-256 Kbps

·         Based IP protocol

·         Ethernet LAN interface 10baseT and 100BaseT

Service Options

·         IP VSAT Transaction Low Traffic

For applications with low traffic such as:

-          airline tickets & hotel reservations

-          Authorize credit card

-          ATM

-          Point of Sales transactions

·         Transaction IP VSAT High Traffic

For applications with medium traffic such as:

-          Delivery Data

-          E-mail, LAN to LAN, intranet, and internet access

-          Online between branches (such as banking applications)

·         IP VSAT Closed Users Group

For applications with high traffic such as:

-          Low - Medium traffic

-          To transfer files, SAP, downloads, etc.

-          The number of remote and transmission method is determined by the customer

VSAT LINK

Data communications services that use satellite access media technology with SCPC (Single Channel Per Carrier) to link point to point (point-to-point) and can be developed to link the point to many points (point-to-multipoint). VSAT Link provides personal bandwidth that require communication in large quantities and continuously with location that is not covered by the wire service. This service can be used for data communication, voice, image and video.

Allotment :

Data Communication

·         The LAN connection to LAN-based IP protocols

·         Transfer files and pictures / large image, such as CAD / CAM and video files

Voice Communications

·         The direct voice communication with the telephone between the two locations (Direct Line)

·         Voice communication through a central network of local private (PABX)

Video Communication

·         Interactive communication through video and sound (video conference) with business partners in different locations

Features

·         Have a high level of security because it is a private network

·         Many choices of speed in accordance with customer needs to reach up to 2 Mbps with full duplex configuration (both directions)

·         VSAT service coverage to reach all parts of Indonesia Links

·         Service Level Agreement of 99%

·         Service interruption complaints 24 hours a day, 7 days a week

·         Coverage area of services in 49 cities in Indonesia

Benefits

·         Economical, especially to the relationship some remote location outside the city

·         Flexibility in technology because it is easily linked with other Lintasarta services as an integrated solution

·         Flexibility in installation, especially for locations that are beyond the reach of cable or a location far from the central business districts

·         Reliable because it is supported by the operational 24 hours a day, 7 days a week

Technical Specifications

·         Data rate 38.4 Kbps - 2048 Kbps

·         RS-232 interface, RS-449 or V.35

·         Configure two-way (full duplex)

·         Modulation BPSK / QPSK

·         A clear channel configuration that can be passed through communication protocols such as:

-          X.25

-          SDLC

-          X.28

-          SNA

NET VSAT

A service data communication system that uses satellite technology with media access MultNetlex Time Division (TDM) / Time Division MultNetle Access (TDMA) based on standard protocols Legacy. NET topology VSAT system in the form of star with a hub and a remote system. At each remote station, computer and customer devices connected to the terminal via the Digital Indoor Unit (DIU). Hub to communicate with a remote antenna using TDM channel while the remote antenna to send data to the hub using a TDMA channel.

Allotment :

VSAT NET according to the types of applications as follows:

Transactional and interactive applications

·         Online inter-branch

·         Reservation hotel / airfare

·         ATM (Automated Teller Machine)

·         Traffic data is small

Application of remote terminal / telnet / terminal emulation with a centralized data base

·         Data entry

·         Control of stock (inventory control)

·         Payment point

Features

·         Have a high level of security because it is a private network with satellite broadband technology NET

·         VSAT services reach all areas of Indonesia are covered by the Palapa B4 satellite coverage

·         Provision In Door and Out Door Unit

·         Service Level Agreement of 99%

·         Service interruption complaints 24 hours a day, 7 days a week

Benefits

·         Economical, especially to the relationship some remote location outside the city

·         Flexibility in technology because it is easily linked with other Lintasarta services as an integrated solution

·         Flexibility in installation, especially for locations that are beyond the reach of cable or a location far from the central business districts

·         Reliable because it is supported by the operational 24 hours a day, 7 days a week

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Antenna Diversity

ANTENNA DIVERSITY

One way to achieve diversity isusing a two- channelreceiverthat is free from fading . The possibility of both is affected by fading in the same time is small. This method requires 2 Rx antennas at the Base Station to receive the same signal, it is not affected olehkarena differences caused by fading.

By selecting the best of the two signals, due to fading can be reduced. There are two ways to do this, namely:

Space Diversity: The distance between the antenna must be such relationships in the two-antenna signal, which is low. Relationships are the equations that describe the statistical limits of the signal. In practice, the distance should be a few meters. At 900 MHz is possible strengthening of 3 dB, used a distance of 5 to 6 meters between the two antenna .. At 1800 MHz the distance would be minimized because a smaller wavelength.

Polarization Diversity: Antenna Dual Polarization is: an antenna device with 2 rows with the same physical unit. Both lines can be arranged and directed in various ways during the second plan of polarization have the same performance by strengthening and examples of radiation. Two forms are commonly used together, namely: Vertical and Horizontal rows and rows in the slope of 45 °.

Formatting BURST

Information superimposed on one time slot in TDMA frame by Air Interface commonly called Burst (split). TRU (contained in the RBS) and MS perform the function of putting information into the form of actual burst. There are five different types of burst, namely:

NORMAL BURST

Used to carry information on the Traffic Channels and Control Channels; BCCH, PCH, AGCH, SDCCH, SACCH and FACCH.

Normal burst contains 57 bits of data packets encrypted or voice, 2 flag bits, 26-bit Training Sequence, and two packages of 3 bits, called tail bits. Flag bits (Stealling flags) indicate the FACCH signal is in the process. Training sequences are known as examples of bits used by the equalizer to make the channel model. Tail bits are always 0,0,0 and used to help the equalizer indicate start and stop points. A ts is room to 156.25 bits, but the burst only contains 148 bits. Time 8.25 empty and called the Guard Period, which is used to protect the burst of overlapping and others.

Frequency Correction Burst

Used to carry data in the Frequency Correction Channel (FCCH).

Synchronization Burst

Digunakan untuk membawa data pada Synchronization CHannel (SCH).

Access Burst

Used to carry data in Random Access Channel (Rach). It has a Guard Period longer to justify the fact that MS does not know the timing advance value for transmission on the first access. MS can be far from BTS that indicates the initial burst would arrive late.

Dummy Burst

Not carry information, and sent from the BTS on ts who are not carrying traffic, providing the charging carrier. The format is similar to the Normal Burst, except without the flag bits

WITH BURST AND FRAME

• TDMA frame structure through the air begins to burst and developed until Hyperframe. Development occurs as follows:

• TDMA frame consists of 8 time slots. Each time slot carrying a single burst.

•  26 Traffic Channel TDMA frame containing a traffic channel multiframe; used to carry the TCH, SACCH and FACCH.

• 51 Control Channel TDMA frame contains a control channel multiframe; used to carry BCCH, TCCCH, SDCCH and SACCH.

·         A superframe consists of 51 or 26 traffic channel multiframe control channel multiframe another.

·         Hyperframe superframe consists of 2048

SIGNAL STRENGTH MEASUREMENT

Measurement of signal strength on idle mode and active mode

Idle mode

Idle mode occurs when the MS condition on but not connected (MS does not send a signal). When the MS in the conditions on, the MS is measuring all radio frequencies in the system and provides the signal strength for each frequency. MS to tuning into the best cell to receive messages or to request a connection. MS continues to monitor all the nearest cell, and also there is a better cell, the MS will to tuning into the cell.

MS is constantly updated measurement report containing the average signal strength to the nearest cell-cell, power and BER fractions of base stations serving. Signal strength from the serving BTS is measured each time by the MS receiving the assigned time slot.

Active mode

Active mode occurs when the MS communicates with the network. Both MS and the BTS serving (serving BTS) to measure the signal strength on the radio link. MS secra continuous reporting to the system of how strong the signal strength received from BTS. This measurement is used BSC to make the decision to target cell when the handover occurs.

MS also measures the quality (BER) on the downlink of the serving cell (serving cell). The measurement results are provided in MS and the average measurement calculated for all values provided for a period of 480 ms. Value calculations are sent to the BTS in the form of a report measurements every 480 ms. The average value of measurements for each carrier and then obtained and reported to the BSC. To ensure the measurement results related to the actual base stations, base station identity must be ascertained. The identity of the BTS is given in the BSIC, sent by SCH, time slot 0, carrier 0.

MS procedure when a new active:

1. MS receives and measures the signal strength in the serving cell, time slot 2. 
2.  MS transmits.
3. MS measure signal strength to at least one of the nearest cell.
4.  MS read BSIC in SCH (time slot 0) to one of the nearest cell.

Six cell-cell closest to the average value of the highest signal strength and validation BSIC then reported to the BSC through the SACCH. When MS is not synchronized with the cell-cell closest, MS does not know when the time slot 0 in the BCCH-carrier will occur. Therefore, MS can be measured through an extended time period, at least 8 time slots, to ensure that the time slot 0 will occur during the time of measurement. All this is carried out during the IDLE frames.

Measurement Report

• Measurement reports consist of all data sent to the system by MS during the relationship lasts. The report was sent on SACCH every 480 ms. The data include:

• Signal strength on the serving cell.

• Mobile power is used.

• Timing Advance Value is used.

• Transmission Discontinues used or not

• The quality of the serving cell.

• Signal strength of cell-cell nearby.

• cell-cell numbers were reported nearby.

• Frequency BCCH to reports of cell-cell nearby.

• BSIC to report the nearest cell-cell.

AIR interface

AIR INTERFACE

Water Interface using the technique of Time Division Multiple Access (TDMA) to send and receive channels and signaling information between the BTS and MS. TDMA technique is used to divide each of the carriers into 8 time slots. Time slots are then marked for specific users, allowing to deal with 8 conversation simultaneously on the same carrier. Air Interface Characteristics:

FREQUENCY BAND

• "Over the water" bit rate of 270 kbps

•  Distance duplex 45 MHz (GSM 900), 95 MHz (GSM 1800) or 80 MHz (1900)

• 200 kHz channel separation

• Modulation uses Gaussian Minimum Shift Keying (GMSK)

AIR INTERFACE CHANNEL

The usual path for carrying information between MS and BTS is known as Physical Channel. Differences in the Physical Channel information carriers are classified as Logical Channel. Logical Channel is divided into 2 categories, the Control Channel and Traffic Channel. Both were then divided again, there are two types of Traffic Channel and there are three categories of the Control Channel with a total of nine different types.

CONTROL CHANNEL

Control channels carry signaling information used by MS to look for RBS, synchronize itself with the RBS, and retrieval of information used for the implementation of the call set-up. There are three categories of the Control Channel, namely:

Broadcast Channels (BCH)

All BCH are transmitted point-to-multi-point downlink direction.

Frequency Correction Channel (FCCH)-Provides frequency correction information used by MS.

Synchronization Channel (SCH) - Contains the Base Station Identity Code (BSIC) and TDMA frame number is used for synchronization of MS for the structural frame of the new BTS.

Broadcast Control Channel (BCCH) - Used to broadcast general information to all MS.

Common Control Channels (CCCH)

All CCCH transmitted point to point.

Random Access Channel (Rach) - Used by the MS to request access to the system. Rach Information sent through the uplink.

Paging channel (PCH) - Used to page the MS. PCH Information sent through the downlink.

Access Grant Channel (AGCH) - Used to mark the SDCCH. AGCH information sent via the downlink.

Dedicated Control Channels (DCCH)

All DCCH sent in point to point through the uplink and downlink.

Stand-alone Dedicated Control Channel (SDCCH) - Bringing information during call setup signaling.

Slow Assosiated Control Channel (SACCH) - Send the call control data and report measurement.

Fast Assosiated Control Channel (FACCH) - Takes a critical signaling information.

TRAFFIC CHANNELS

Traffic Channel (TCH) carry voice / data. There are two types of TCH, namely: Full-Rate and Half-Rate. TCH time slots can be placed anywhere on any frequency is described in the cell, except for the first time slot (TS0) the first carrier (C0).

Full Rate - Full Rate TCH handle voice or data encoding. TCH information sent to the bit rate of 33.8 kbps.

Half Rate - With half rate channel, a MS will only use every second time slot (every other idle). As a result, two MS will be able to use the same physical channel to lead the call to a doubling path capacity.

SIGNAL PROCESSING

Before sending information through either the Air Interface Traffic Channel or Control Channel signal processing. During the change of Signal Processing, to reduce the possibility of interference during signal transmission takes place through Air-Interface

Speech coding

PCM speech code into the TRC or BSC / TRC on the A interface with the speed of 64 Kbps. Eight of these channels can provide bit rate of 512 Kbps via AirInterface, without the transmission could not. Traumatic to the TRC or BSC / TRC, providing coding segments point to talk to 20 ms. 20 ms speech segment is then entered into the speech coder. Speech coder will analyze the segment and perform the bit rate reduction. The output is a code point talking point talking to the quality acceptable, ie at 13 Kbps. 3 Kbps others in band signaling added to the signal, so the total output coming out on A-ter interfaces or A-bis interface is 16 Kbps.

Channel coding

Used to detect and fix errors that were identified during the process of signal transmission. This error signal has been measured in percent of total bits dikirim.kualitas shows the limits of signal transmission Bit Error Ratio (BER). Error bit BER is the percentage of the total bits transmitted.

Channel Coding run in TRU in the downlink and the uplink signal from MS. There are two types of Channel Coder normally used, namely block coders and convolutional Coders.

Coding channels delivering 20 ms speech pieces - pieces of the speech path that contains 260 bits of information talks. 260 bits of information are divided into:

• 50 bit is very important

• 132 bits that are important

• 78 bits that are not so important

3 bit parity is added to the 50 bits (block coding). 53 bit is shared with 132 bits are important and 4 tail bits diencoding together into 378 bits (1:2 rate). The remaining bits are not encoded.

 Interleaving

Bit errors often occur because of solving the information sent through the air (air interface). This is due to the long fading affecting bits lined. The process of channel coding is only effective in detecting and correcting single errors. Interleaving solve this problem by dividing the bits of information in the form of messages and transmits these bits are not regular (this can also overcome the problem of noise). Through interleaving, ntuk single frame of information scattered through several solutions. GSM is used in two levels of interleaving, namely:

First Level

Channel coder provides 456 bits for every 20 ms speech channel

Second Level

In normal solution contained a space for every 2 bits of the block 57 bits of information. The second level of interleaving using 8 bits from 57 bits to be transmitted and placed in 8 different information bursts. Any information bursts consist of 2 blocks of 57 bits of information for each instance a different voice channels.

With the second level of interleaving we can now lose one full burst. Since the loss of one burst only affects 12.5% of all bits of each speech frame, the channel coding can to make the appropriate corrections.

Equalization

Time Dispersion occurs when the transmission signal reflected away from the RX antenna and separated from the original signal. Interference signal will be scattered by time and the symbol adjacent to each other. Recipients can not receive the original signal transmitted. Equalization is the process used to overcome the time dispersion. Equalizer to overcome the reflection that occurs in limited amounts, with the delay of 15 us who have the signal path about 4.5 miles.

Equalizer create transmission channel and calculates the possible transmitted sequences. Data is transmitted in bursts that are placed in a timeslot. Training sequences are used to create models of the canal. This model changed over time, but during a burst is considered to remain constant. The reflected signal caused by Rayleigh fading to a close reflection region. These signals have independent fading pattern compared with the direct one and can be used by the equalizer to add to his ability.

CIPHERING

Chipering is a technology used to minimize the interception of GSM. Ciphering development has a place in the form of digital signals 1 and 0 are random. Random shape is only known by the MS and BTS. The result is a signal that is unintelligible to all MS, or can only be received by stations that have the same code. Algorithm AS / 1 and AS / 2 is very possible to be used in GSM systems. Network operators have several surgical options in using the ciphering mode or other algorithms that they want.

TRAFFIC CHANNEL OFFSET

The structure of the downlink and uplink are very identical. The difference is in the setting of time or time slot; TS2 in the down link is not the same happen to TS2 in the uplink. Pengesetannya use 3 timeslot. This means that MS is not necessary, to transmit and receive at the same time.

TIMING ADVANCE

If the MS moves Base Station during the talks would be required to send a burst in time synchronization, in order to be accepted according to the timeslot in the Base Station. BS in continuing to send a value between 0 to 63, tell MS how many bits of time (3.7 us) to synchronize the time when transmitting the burst.

Frequency hopping

Frequency Hopping is where radio frequency on the physical channel to a conversation changed in the period interval. During the TDMA frame N +1, C2 is used. Call will use the same timeslot but different frequencies. There are 64 sections in the frequency hopping. One for cyclic and 63 others are random sequences.

Frequency hopping can be categorized as a tool to reduce the occurrence of interference. Two obvious types of frequency hopping implemented in the RBS 2000, namely:

Hopping Synthesizer

Hopping Synthesizer is the process of tuning the output frequency to transmission into the marked channel, send a burst of information, and retuning the output frequency to transmission to the next channel and repeat the process again.

Baseband Hopping

Baseband Hopping is the process of tuning to multiple frequency transmission to the output channel that is marked. Any information will be sent by one burst transmitter, and then burst into the transmitter that dituning held to a different output frequency, and repeat the process.