Ofcom (UK) and the Government have decided that a new organization should be established and run by the new 800 MHz band licensees to manage this interference mitigation.

• The interference model calculates the probability of interference from new LTE transmissions in the 800 MHz band to existing DTT coverage and identifies the set of pixels to which information and filters need to be sent in order to meet the standards defined in Key Performance Indicators (KPIs), and produces a list of addresses of potentially affected households
• The model is based on output data provided by the broadcasters UK Planning Model (UKPM) but can also be calculated by ICS designer and ICS telecom

All features required to perform the DTT vs LTE are now available in ICS designer and ICS telecom.

General description of the method

Inputs

• A text file containing X, Y, address, households, mS, sigmaS, mU, sigmaU
• Coordinates (lat or Y / long or X / Coordinate code)
• Number of households within the pixel
• Received wanted signal power median (dBuV/m)
• Received wanted signal power standard deviation (dB)
• Received DTT interferer signal power median (dBuV/m)
• Received DTT interferer signal power standard deviation (dB)
• Serving DTT transmitter and channel numbers
• Clutter data relevant to propagation (i.e. urban, suburban,open)
• Resolution of the text file: User defined (by default 100m*100m per address)
• A DTM with a given resolution lower than or equal to 100m
• Location and parameters of all LTE stations to be considered
• C/I protection ratios
• Parameters of the propagation model. Any model available in ICS designer or ICS telecom can be used for this study (1546-4, 1812-2 modified, 525/526, …)

Calculations

• For each address point, calculation of DTT location probability q due to interference from DTT stations only. This will be made using (mS, sigmaS) and (mU, sigmaU) as inputs of the sum of log-normal variables
• Methods: Fenton-Wilkinson, Schwartz and Yeh
• For each address point, calculation of the power received from each LTE station, weighted by the relevant C/I
• For each address point, calculation of mean and standard deviation of the sum of weighted LTE received power, also called mV, sigmaV
• Calculations of mZ, sigmaZ corresponding to the sum of all interfering signals (DTT and LTE) given by (mU, sigmaU) and (mV, sigmaV), according to the sum of log-normal variables
• Calculation of q’ on each address point corresponding to the reduced DTT location probability due to additional interference from adjacent-channel LTE base stations

Report

• A table listing for each address point, 4 fields will be added: (mZ, sigmaZ, q and q’)
• A map giving the value of q’ (in percent) on each address point (by default 100m*100m)

Note : If the DTT stations (location and parameters) are provided, the calculations of mS, sigmaS, mU, sigmaU are also possible with ICS designer and ICS telecom.