Introduction of the report
Objective of the report
Methodology
Theoretical Background of Cellular network 4-
- Detail of GSM Technology
- Architecture of the GSM network
- The GSM Call Setup
- Handover
- Modulation
- The channel concept
- Control Channels
- Broadcast Channels, BCH
- Common control channels, CCCH
- Dedicated control channels, DCCH
- Traffic channels, TCH
The MSC checks subscriber A's number and who he or she is calling (i.e. subscriber B's number). The HLR requests this VLR to provide a visitor address (i.e. the roaming number) for this subscriber. GSM uses Mobile Assisted Handover (MAHO), which means that the MS assists by measuring the signal strength and transmission quality of the traffic channel in use, and also the signal strength of neighboring base stations.
The BS also measures on the active channel, this measuring and reporting continues continuously when the MS is busy. When the MS is turned on, it will search for a suitable RBS to register and listen to. Once the MS has found the strongest carrier, it must check whether this is a BCCH carrier.
FCCH serves two purposes; one is to make sure it is the BCCH carrier, the other is to allow the MS to synchronize with the frequency. The next thing for the MS is to synchronize with the TDMA frame structure within this particular cell, and also to make sure that the selected base station is a GSM base station. Listening to the synchronization channel, SCH, the MS receives the TDMA frame number and also the base station identity code, BSIC, of the selected base station.
The last information the MS needs to get to start roaming, waiting to arrive or making calls, is some general information about the mobile. This is transmitted on the Broadcast Control Channel, BCCH, and includes, among other things, the Location Area Identity (LAI), the maximum output power allowed in the cell, and the BCCH carriers for neighboring cells in which the MS will perform measurements. Now the MS is tuned to a base station and synchronizes with the frame structure in this cell.
The base stations are not synchronized with each other, so every time an MS decides to camp on another cell, its FCCH, SCH and BCCH must be read. At certain time intervals, the MS will listen to the paging channel, PCH, to see if the network wants to contact the MS. The information on the PCH is the paging message, including the MS Identification Number (IMSI) or Temporary Number (TMSI).
RACH can also be used if the MS wants to contact the network, e.g. The MS is informed on the SDCCH which physical channel (frequency and time slot) to use for traffic (TCH).
Transmission part 18-
- Call Transmission in Network
- Antenna
- BTS
- HiT Room
If mobile unit A is communicating with mobile unit B. Assume that MS unit is connected to BTS DHDHNC and MS B is connected to DHMPC, if they are communicating with each other, then first create a connection between them. 3.3) Antenna: Mobile unit connected to BTS with GSM antenna. The radiation pattern of an antenna is the geometric pattern of the relative field strength of the field emitted by the antenna. Impedance: Impedance matching is the practice of shaping the input impedance of an electrical load to maximize power transfer or minimize load reflections.
Polarization: The polarization of an electromagnetic wave is defined as the orientation of the electric field vector. Polarization is described by the geometric figure traced by the electric field vector in a stationary plane perpendicular to the direction of propagation as the wave travels through that plane[9]. One frequency is used to transmit signals to mobile stations and the other to receive signals from mobile stations.
Transmission interface equipment includes RBS, rectifier, battery, DDF (digital board frame), IDU (indoor unit), Tx rack, PDB, DVS. The indoor unit is connected through the outdoor unit via IF cable, IDU also performs call processing to DDF (digital distributed board) where Tx and Rx are matched. The input current of the power card provides a suitable DC voltage (53.4Vdc) for other equipment.
The battery provides DC voltage (48 volts) and supports other BTS equipment when the power is off. if the battery does not carry voltage, the connection is broken, so another option is a generator that produces current. When the room temperature is high around 38C in the hot season, it automatically switches on and adjusts the room temperature to the outside room temperature. The indoor unit is connected through the outdoor unit with an IF cable, and then the signal passes through the microwave antenna.
3.5) HiT Room: HiT Room Contains IDU, ODU, hybrid converter, rectifier and hiT (Surpass 7070), battery and AC. It is a platform that covers the entire range of network applications required for the regional core and metro.
Point to point link 25-
- Transmission antenna
- Line-of-Sight Equations
- ODU
- Optical fiber Link
- Types of optical fiber
- Suitable Media for Optical Communication
Refer to the Department of Engineering where information is transmitted using radio waves of the wavelength of centimeter range through the use of various electronic technologies. Each of the fibers in the core is covered by a cladding that has different optical properties than the core. The outer part of the optical fiber consists of plastic or other materials, which is called the jacket.
The mobile tunes to the strongest provider and discovers whether it is a BCCH provider. The mobile may optionally include a BCCH bearer memory of valid BCCH bearers in the home PLMN. Based on the measurements, a list of the six strongest carriers is regularly updated by the mobile.
During a call, the mobile continuously reports (via SACCH) to the system how strong the received signal strength is from the BTSs in its vicinity. The signal strength of the serving cell is monitored during reception of the TS assigned to the mobile phone. An average value of the measurements is then derived for each carrier and reported to the BSC.
Now, to ensure that the measured values correspond to the correct BTS, the identity of the BTS must also be determined. The link budget is the calculation of all gains and losses from the transmitter, through the medium (free space, cable, waveguide, fiber, etc.) to the receiver in a telecommunications system. It calculates the attenuation of the transmitted signal due to propagation, as well as antenna gains, feed line and miscellaneous losses.
Minimum signal strength at the input of the radio, at which point the "Bit Error Rate (BER)" in the link has a specified value. These factors can include minor misalignment of the antennas, losses due to fog and rain, etc. Free space loss refers to the reduction in signal strength when the signal radiates away from the source.
Therefore, the telecom sector has come forward to help these underprivileged people in rural and hill districts with the aim of giving them a better future. The Grameenphone operators have been given another opportunity to intensify their rivalry as they battle to win customers in the hills. districts that will be opened to mobile telephony. Grameenphone Telecom's GSM network will cover 64 districts of Bangladesh to ensure their service can seamlessly reach every corner of the country.
Measuring part 32-
Link budget
Conclusion
Future Work
