December 2002 Volume 1, Number 1INTRODUCTIONThis paper introduces a few of the more common alter-nativestotheusualRF(radiofrequency)planningsolutions for coverage deficiency problems. These meth-odsarebeingappliedafterorconcurrentlywiththeRFdesign activity, as well as during the implementation andoperations phases of network life.Fivesolutionsforcoveragedeficiencyproblemsaredescribed in this paper, namely: Microcell Solution - 1 Off-Air Repeater Solution - 2 FO (Fiber Optic)/RF Solution - 3 (with two options) TMA (Tower-Mounted Amplifier) Solution - 4 Leaky Coax Solution - 5 (with two options)Each of the solutions is presented in a general descrip-tion with an illustrative diagram and/or figure, a configu-ration to suit the proposed example, and implementationnotes. The options demonstrate the flexibility that needsto be present in RF designs. These examples also providevaluablepointsofcomparison.Generalrecommenda-tions are provided in the Conclusion. Although the exam-plesaredescribedusingU.S.measurementunits,theprinciples are easily transferred to international applica-tions and metric units.Example of Coverage Objective and LimitationsA hypothetical town that stretches 1,000 yards along arelatively straight portion of a two-lane road is chosen astheexampleforcoveragedeficiency.Theportionoftheroad that runs through the town, as well as the first rowofshopsonbothsidesoftheroad,shouldbecoveredwithstreetlevelcoverageat-95dBmwith95percentreliability.Itwillbeassumedthattherestoftheroadiscoveredat-95dBmlevelorbetter.Accesstothelightpolesalongtheroadhasbeengranted,buteveryothertype of installation is prohibited by the town.Solutions Are VersatileEven though the methods are applied in this paper toaGSM(globalsystemmobile)telecommunicationssys-teminthe1900MHzPCS(personalcommunicationservice) band for ease of comparison, in principle, thesemethods can be used successfully for a range of wirelesssystems in PCS and other bands.MICROCELL SOLUTION - 1The road and the buildings on each side of the road canbe covered with a 5W microcell. This solution providesomni coverage, with maximum coverage in the middle ofthe town and minimum coverage at the town edges.ConfigurationOne 5W microcell should be installed in the middle ofthetownatthebaseofthelightpole.One-in.coaxcable will run up to 20 feet on the light pole to the single3-footomniantenna.SeeTable1 forthedetailedlinkbudget.According to this prediction, the RSSI (received signalstrengthindicator)levelof-95dBmcanbeexpectedat600 yards from the antenna location with 95 percent reli-ability. (This link budget is provided only as an example.TheRFdesignsoftwarepackagewithitscorrespondinglink budget should be used to plan the real system.)Implementation NotesThisdesignispartoftheregularRFplanning/designprocess,aswellasImplementationprocess,exceptforthefollowingstealthingrequirements:Thecoaxcableshouldbeorderedinaspecificcolortomatchthelightpole,whiletheantennaandmicrocelloutdoorcabinetcan be painted for stealthing.See Figure 1 for an example of the installation.37Alternative RF Planning SolutionsforCoverage DeficiencyAleksey A. Kurochkinaakuroch@bechtel.comIssue Date: December 2002Bechtel Telecommunications Technical Journal OFF-AIR REPEATER SOLUTION - 2Off-airrepeatersarebi-directionalpoweramplifierswithgainsvaryingfrom50to90dB.Theyprovidecoverage by repeating the frequency of the base stationin areas that lack coverage. There may be some overlap,but this overlap should be minimal. This solution requirestwooff-airrepeatersandtheassumptionthatthereissufficientsignallevelfromthetwodonorcellsoneachside of the town for the repeaters to operate.ConfigurationOne off-air repeater should be set up in the area of thereliable signal received on the donor antenna outside ofthetown.Thetransceivercoverageantennaoftherepeatershouldbedirectedtowardthetowncenter.Ifone repeater does not provide satisfactory coverage, thesecond repeater should be installed using the other cellas a donor.Figure 2 shows a system drawing of an off-air repeatersystem.38Project Name: 1000 Yard Town 4.00