A15.3 CDMA UL - ENHANCEMENT TO ALLOW CELL SELECTION

A15.3.1 Flow chart

Figure 449: Flow chart of the CDMA UL “Cell selection” implementation (in red) with respect to the initial CDMA UL (in black)

A15.3.2 Algorithm

Convention: i is the index of the cells

1. Balance the power of the UE (i.e. set their Tx power) (internalPowerBalance()), the reference network capacity is calculated with the average noise rise reaching the defined threshold (i.e. targetNetworkNoiseRise input to SEAMCAT, usually 5.5 dB or 6dB) without external interference (i.e. cellNoiseRiseInitial[i] )
2. Calculate the average noise rise (with external interference) in the whole network and the noise rise in each cell (i.e. cellNoiseRiseInterferer[i])
3. Arrange the active users in a list so that they are sorted based on their Tx power (i.e. activeUsers)
4. Calculate the relative cell noise rise which is the difference between noise rise with and without external interference for that cell.(i.e. relativeCellNoiseRise[i] = - cellNoiseRiseInitial[i] + cellNoiseRiseInterferer[i])
5. If the network average noise rise is above the value of noise rise averaged in a network calculated in step 1  then start the process of dropping users.
6. Selection of the algorithm between ‘average noise rise in a network’ or ‘ noise rise per cell’ (choice made by the SEAMCAT user)
7. ‘Average noise rise in a network’ selected
   While ‘network average noise rise’ > ‘initial network average noise rise (step1)’
   - Remove user(s) from ‘activeUsers list’ (start with users having highest power level)
   - Re-optimize network (re-balance the power of the UEs) to achieve a new ‘network average
      noise rise’ value
   When ‘while loop’ finished, continue with step 12.
8. ‘Noise rise per cell selected’
   Loop to identify the affected cells based on relativeCellNoiseRise[i] 
   If - cellNoiseRiseInitial[i] + cellNoiseRiseInterferer[i] > TargetCellNoiseRise  then Cell[i] is considered affected. The TargetCellNoiseRise (in dB) is an input to SEAMCAT set to a default value of 0.1 dB. 
   You have the freedom of choosing a different value. The algorithm will select cells fulfilling above criteria and assess those cells whether to drop users from those cells or not. The default value has been chosen to ensure that the analysis does not disregard any cases of interfered cells, since users may also be dropped as the consequence of a low noise rise.  A list of affected cells is created (i.e. selectedCell).
9. Sort the list selectedCell so that the cell with the highest relative noise rise is the first element
10. Start loop over the sorted list selectedCells (starting from the first element)
    1. Extract the active users of selectedCell[i] from activeUsers into a list selectedCellActiveUsers (one list per cell)
    2. Calculate the current new noise rise for selectedCell[i] (i.e. currentCellNoiseRise[i]).
    3. Start removing (i.e. dropping) the active users from selectedCellActiveUsers (by default the ActiveUsers list is reduced). The UE with strongest Tx power is removed first.
    4. Proceed with internalPowerBalance() over the remaining users for the whole network
    5. Calculate the new noise rise for selectedCell[i] (i.e. currentCellNoiseRise[i]).
       If currentCellNoiseRise[i] >cellNoiseRiseInitial[i], continue until there is no more users or the cell noise rise is below or equal to cellNoiseRiseInitial[i].
       Calculate the average network noise rise for output processing.
       If average noise rise below the targetNetworkNoiseRise exit the loop.
11. Outside the loop
12. Note that for each event the optimized number of UE is being re-calculated.
13. Produce:
    1. Save CDF of number of users in reference cell and whole network for initial optimized network (without external interference) and final optimized network
    2. The CDF of the capacity loss in the reference cell and in the whole network (for each event, calculate the capacity loss in %).
    3. The CDF of the capacity loss in the worst cell_{per event} (the first strongest cell: selectedCell[1]). Only if ‘Noise rise per cell selected’. The cell-ID can be different from event to event but the capacity loss is to be extracted).
    4. The number of cells affected per event.
       Only if ‘Noise rise per cell selected’.
    5. Get vector of average network noise rise (initial optimized network (without external interference), initial optimized network (with external interference) and final optimized network)