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• Site Location: Verify the actual position of the site ,Coordinates checked by GPS. Should be accurate. Beam clearance.
• Network Diagram: The sites are plotted on the tool/map to produce an initial network. Determine the link capacity from the sites traffic. Check the LOS on the tool.
• Path profile: Produce path profile, taking into account the TRS heights, earth bulge, average vegetation, average building height, fresnell zone clearance.
• Radio Surveys: Perform practically the LOS check by flash test , balloon test or path study.
• Site survey: Detail site survey conducted.
• Frequency consideration: Check according to the area, which frequency band will be suitable. Plan according to the hop length and link availability.
• Network operators want the network be error free at every time.
• This is the ideal situation for any network which is not possible.
• There are certain quality standards set by ITU-R for the MW planning.
• Unavailability: When the system is unusable for more than 10 sec, also when BER is worse than 10exp-3,the system is said to be unavailable.
• Unavailability Standards: According to ITU-R, the period of unavailable time begins when in at least on direction of transmission, either one or both of the conditions occur for 10 consecutive seconds. Either the signal is interrupted or the BER in each second is worse than 10 exp-3.These 10sec are the part of unavailable time.
• Available time: When the system is restored and the BER becomes better than 10 exp-3 for the 10 consecutive seconds, this time called available time.
• The beam refracted in such a way that it does not receive at the other end. use space diversity with large antenna spacing.
• Rain.
• The water molecules absorb the MW energy, greater the size of water droplet more energy absorbed. Snow and mist also causes unavailability. Improved by increasing the system gain, also polarization diversity may be employed. Low frequency band be used. Fade margin be kept large.
Duration of outage is determined by the length of time maintenance team take to repair or change the equipment or MTTR.Can be minimized by using HSB systems or twin path.
• The Radio beam is an electromagnetic wave front wide enough .
• The path the electromagnetic waveform depends on the troposphere. (lower portion of the atmosphere).
• In the atmosphere the density of the atmosphere decreases with altitude.
• The upper portion of the wave front travels faster than the lower.
• The beam bends downwards , called refraction.
• The bending effect is handled by adding the factor k. k<1,ray beam bends away from the earth, k>1,ray beam bends towards the earth.For normal system planning k=4/3.
• Receiver Threshold: The minimum level through which the MW link works is the threshold value.
• Receive signal level: The amount of signal that the antenna is receiving.
• Fade Margin: The difference between the nominal receive level and the threshold is available as the safety margin against fading, this is known as fade margin.
• The area around the visual line of sight that the radio waves spread out into after they leave the antenna.
• This phenomena results from the electromagnetic wave theory thatthe wave front has expanding properties as it travels through space. The amount of additional clearance that must be allowed to avoid reflections and attenuations are expressed in fresnell zone.
• The 60% of the fresnell zone must be clear from all type of obstacles in order to achieve the required RSL.
• The fresnell zone increases with length of hop.
• The fresnell zone decreases with increase of frequency.
• Stars (Hubs): These are defined as the nodes that connects to the several sites via chains or spurs.
• Chains: The no of sites connected in sequence.
• Spurs: These are defined as the single link connected to the hub site.
• In this network we can connect maximum 8 sites in star and 3 sites in a chain.
• BSC sites and Hub sites: BSC site usually requires a large no of microwave terminals. In this network traffic from the Nokia outdoor units collocated with Siemens HUB through DDF and a highcapacity multiplexer HiTi7070 to Nokia BSC3i.Traffic from the HUB sites is going through Siemens MW link to BSC.
• TP has three band chunks allocated from FAB in the 18,23,38 GHZ frequencies.
• There are 8 spot frequencies (28MHz BW) in 18 GHz , 5 spot frequencies in 23GHz band and 38 GHz band.
• The sub bands in 18GHz are B and C and in 23GHz and 38 GHz are sub band A.
• All frequencies allocated in 28MHz spacing are used for 16*2 or 34Mbit/s capacity, in order to satisfy the 8*2,4*2 and 2*2 capacity, the channels are split into 14,7,3.5 MHz.
• Propagation factors require that 38GHz should be used for smaller hops, while 18 GHz and 23GHz for longer ones.
• High and Low end sites should be taken properly.
• NetAct Transmission planner is a graphical tool that provide support for all transmission network area required by planner.
• Transmission planner has five modules:
1. Cellular module.
2. Conduit module.
3. Transmission module.
4. Primary Rate path module.
5. Detail module.
• Cellular Module: This module models the logical connection layer (including BTS,BSC,MSC and their logical connections) and uses nodes which are visible in the transmission view. Basically in this module we define which BTS goes to which BSC and the configuration of the BTS (TRX configuration ,BCF ID,BTS ID).
• Conduit Module: The conduit module models the physical cable infrastructure. Basically in this module we define which BTS goes to which BTS and the type of the link (Fiber optic, Radio link).
• Transmission Module: In this module we define the route of the sites and how to go to the BSC. Also we define the type of site in this module (BTS,FIU,Metrohub..)
• Primary Rate Path Module: In this module we gave ET to the sites and define its termination.
• Detail Module: The detail module defines the detail level information about the actual physical devices in the network. This information includes the block diagram showing the units and theinterfaces of the devices, interconnection between the interfaces and cross connections within the devices.
• After this we can get the BSC report (site ID, site configuration, BCF, BTS,TRX IDs.), Cross connections, Detail connectivity, Abis allocation plan etc.