power control

RAN146 Power Balancing

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For dedicate dedicated d channel, channel, in case case of SHO, closed closed loop power power control control is necessary necessary for DL (power (power balance between between node Bs)

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Normal Normal DownL ink Inner Inner L oop Power Power Control: Control:

1- UE measures the S IR on DL DPCCH during the pilot period (in S HO after MRC) 2- UE generate generate T PC commands commands 3- Upon receiving the T PC commands commands BS adjusts its downlink DPCCH/DPDCH power power accordingly •

Benefit from power balancing power control in DL:

SHO usually happens on the edge of cells, which means the channel condition is not good enough. It’s very likely that Node B would

misinterpret misinterpret TPC commands during SHO. SHO. if the real TPC command is UP, UP, and any one of the Node B mis-decodes it as DOWN. It will result in smaller Eb/N0 than expected expected on UE side, which would lower the gain of soft combining. combining. If the real TPC command is DOWN, and any one of the Node B mis-decodes it as UP. UP. Though it will not impact UE receiving. It is a waste of power and impacts the power level of other UEs, i.e. impacts the capacity of whole cell. During SHO, all cells in the active set receive the same TPC and acts accordingly. accordingly. But any one cell receives TPC erroneously that could impact the transmit power of that cell which will lead to power drift that eventually lead to uncoordinated links. Power Balancing prevents this Power Drift issue.

Our trial: Abbr Ab brev evia iate ted d Na Name me

MO Class

Parameter Category

Full Name

Description

Range and step

AdjustmentPeriod

RNAC

• Advanced parameters

Adjustment period time

1 .... .2 .2 56 56 f ra ra me me s, s, s tte e p 1 f ra ra me me s

AdjustmentRatio

RNAC

• Advanced parameters

Adjustment ratio

MaxAdjustmentSte RNAC p

• Advanced parameters

Maximum adjustment step

MinPrefChange

RNAC

• Advanced parameters

Trigger for sending the updated reference power to BTSs

PrefSubtract

RNAC

• Advanced parameters

PowerBalancing

RNFC

• Basic parameters

Reference power subtraction parameter Power Balancing on/off 

This parameter defines the period during which the DL transmitted power has to be corrected to the reference power. Setting this parameter to a small value makes power balancing faster, whereas setting it to a large value makes it slower. This parameter defines the convergence rate (towards the reference power) used for the associated Adjustment Period. Large values cause underestimations to power corrections. If the value is zero, power is corrected to the DL reference power. Defines a time period (in terms of a number of slots) during which the accumulated power adjustment will be no more than 1dB. This va lue does not include the DL inner loop PC adjustment. A small amount of slots grants quick response times for power balancing but may cause overestimations. When RNC calculates a new reference power for base stations, it is not updated to the base stations if it does not differ from the existing reference power in the base stations at least by a value defined by this parameter. Setting this parameter to a small value, such a s 1dB, causes the new reference power to be updated to the related base stations every time the measurement reports arrive and setting it to a large r value causes the reference power to be updated more seldom. In other words, this parameter can be used to limit the amount of messaging traffic related to reference power updates. The reference power (proportional to a cell's CPICH power) is defined by choosing the largest of the averaged DL powers and then subtracting the value of this parameter from it. Setting this parameter to a large value will cause a slight underestimation of the transmission power. This This para parame mete terr def defin ines es whet whethe herr Pow Power er Bala Balanc ncin ing g is is use used d or or not not..

0...100, step 1

Range and Step in issue 04B

Range and Step in release mcRN4. 1 1. .... 25 25 6 1...256 frames, frames, step 1 step 1 frames frames 0...100, 0...100, step 1 step 1

Default Current propose Value Value d value

2 frames

2 0

0 1...10 slot, step 1 slot

1...6 dB, step 1 dB

1...10 slot, step ste p1 slot 1...6 dB, step 1 dB

1...10 8 slot slot, step ste p1 slot 1...6 dB, 3 dB step 1 dB

0...10 dB, step 1 dB

0...10 0...10 2 dB dB, step dB, step 1 dB 1 dB

Powe Powerr Bal Balan anci cing ng is not not in in use use (0), (0), Power Balancing is in use (1)

Power Balancin g is not in use (0), Power

Power Balancin g is not in use (0), Power

Power Balancin g is not in use (0)

8

4

3

1

2

3

Our aim •

Fast aster bowe bowerr bala balanc ncin ing g PC. PC.

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Make power balance more reactive

=> Less interference => More capacity gain in DL.