一些rf计量单位的定义及相互关系.doc

Preliminary Draft – RF Link Model (Author: Trent Messec)Internal Use Only – Do Not DistributeFrom Sector:PiCH (Pilot Channel)PCH (Paging Channel)SynCH (Synch Channel)FCH (Fundamental Channel)DCCH (Dedicated Control Channel)SCH (Supplemental Channel)SCCH (Supplemental Code Channel)QPCH (Quick Paging Channel)PC subCH (Power Control Sub-Channel)Digital GainPower_in_Watts = PilotPwr_in_Watts * (Gch / Gpilot)^2Energy Per Chip (Ec)Depends on WC length Ec = Power_in_Watts / Chip_RateEnergy Per Bit (Eb)Depends on OTA (over the air) data rateEb = Ec * (Chip_Rate / Bit_Rate)Thermal Noise (No)Depends on bandwidth and temperatureNo = k * Temp(Kelvins) * BWLink Noise at BTS output (Ior)Pilot Ec/Ior = Pilot_Ec / Total_PowerLink Noise at Mobile input (Îor)Pilot Ec/ Îor = Pilot Ec/Ior +/- channel effectsLink Noise from other sectors (Ioc)Ioc = Sum(Îor; all sectors except this one)Total Noise at mobile input (Io)Io = Îor + IocPilot Ec/Io = Pilot Ec / (Îor + Ioc)To Include:Link Effects, Multipath, Bit Error Rate, Frame Error Rate, Activity FactorsFrom TIA/EIA-98-C Standard:Ec. Average energy per PN chip for the Pilot Channel, Synch Channel, Paging Channel, power control subchannel, or Forward Traffic Channel.Ior. The total transmit power spectral density of the Forward CDMA Channel at the base station antenna connector.Îor. The received power spectral density of the Forward CDMA Channel as measured at the mobile station antenna connector.Ioc. The power spectral density of a band-limited white noise source (other cells) as measured at the mobile station antenna connector.I0. The total received power spectral density, including signal and interference, as measured at the mobile station antenna connector.Pilot Ec/I0 – Ratio of the combined pilot energy per chip, Ec, to the total received power spectral density (noise and signals), I0, of at most K usable multipath components at the mobile station antenna connector. K is the number of demodulating elements supported by the mobile station.No – The effective inband noise or interference power spectral density. (source: TIA/EIA-97)Nt – The effective noise power spectral density at the mobile station antenna connector.------------Confirm if the following are true:Ior = Sum(Ec, all channels in this cell) = total transmitted energy from a given cellIoc = Sum(Îor, all cells) - Îor _thiscell = total received energy from other cellsIo = Sum(Îor, all cells) = Ioc + Îor _thiscell = total received energy not including thermal noiseNt = No + Io = total received energy from all cells and including thermal noiseEb = Ec * (Rc / Rb)Îor = (Ior / link_losses) * link_gains = total received energy from a given cellG = Geometry = Îor / (No + Ioc) = ratio of total received energy from a given cellto all other received energy.G / (1 + G) = Îor / Nt = ratio of total received energy from a given cellto all received energy-------From TIA/EIA-98-C Standard:Ec/I0 = (Ec/Ior) / (Ioc/Îor + 1)  For a MS not in handoff.Ec/I0 = (Ec/Ior) / (Ioc/Îor + 2)  For a MS in two-way handoff.Eb/Nt = Ec/Ior * Traffic_Chip_Bit / (Ioc/Îor)  For single-path caseEb/Nt = Ec/Ior * Traffic_Chip_Bit * [(1/2)/(Ioc/Îor + ½) + (1/2)/(Ioc/Îor + ½)]  For two-path case (assumes same power both paths)Eb/Nt = Ec/Ior * Traffic_Chip_Bit * [((2/5)/( Ioc/Îor + 3/5)) + ((2/5)/( Ioc/Îor + 3/5)) + ((1/5)/( Ioc/Îor + 4/5))]  For three-path case (assumes same power on two paths, third path is ½ power of one of the other paths)From the above information:Assume:Ec/I0 = (Ec/Ior) / (Ioc/Îor + n)  For a MS in n-way handoff.AndEb/Nt = Ec/Ior * Traffic_Chip_Bit * Multipath_FactorWhereMultipath_Factor = Sum(%PwrThisPath / (Ioc/Îor + %PwrOtherPaths, all paths)Therefore,(Ec/Ior) = (Ec/I0) * (Ioc/Îor + n)  For a MS in n-way handoff.(Ec/Ior) = (Eb/Nt) / (Traffic_Chip_Bit * Multipath_Factor)If we know the minimum Ec/I0 that can be used for pilot detection and demodulation (should be same for all mobiles; or atleast for all mobiles of the same type), and we know the typical or worst-case (Ioc/Îor + n) for a given sector, possibly we can estimate a good Ec/Ior value for that sector.If we know the multipath characteristics, voice activity characteristics, and Ec/Ior at a sector, perhaps we know the Eb/Nt.(Ioc/Îor + n) is just a measure of out-of-sector to in-sector interference for a mobile plus number of handoff links. 。