1. LTE Uplink Power Control

2. UL power control described in 3GPP TS 36.213 Adjusts UE Tx to compensate for channel fading. Reduces inter cell interference Avoids UE from transmitting excessive power. Maximizes uplink data rate. eNB radio receive power maintained for optimum SINR. Prolongs UE’s battery life. Power Control update rate: 1kHZ (1ms = TTI = 1 subframe).

3. Open-loop & Close-loop power control LTE uplink power control is a combination of an open-loop and a closed-loop mechanisms. Open-loop: the terminal transmit power depends on estimate of the downlink path-loss and channel configuration. Closed-loop: implying that the network can, in addition, directly control the terminal transmit power by means of explicit power-control commands transmitted in the downlink. Open-loop power control is used for: ․ PRACH at initial access (Random Access). ․ PUSCH and PUCCH as part of UL power control. Close-loop power control is used for: ․ PUSCH and PUCCH as part of UL power control.

4. UE PRACH TX Power Max allowable UE Pwr Target eNB Rx Pwr Path loss Power UP each attempt by 2dB

5. UE PUSCH TX Power The setting of the UE Transmit power for the transmission in subframe i is defined by: Max UE Pwr Nr. of resource blocks Target eNB Rx Pwr Path loss Transmission format (MCS) Closed loop power control

6. UE PUCCH TX Power The setting of the UE Transmit power for the transmission in subframe i is defined by: Max UE Pwr Target eNB Rx Pwr Path loss PUCCH format Closed loop power control Transmission format

7. Path Loss (PL) estimation  Calculated in the UE in dB. PL = referenceSignalPower – higher layer filtered RSRP  referenceSignalPower  Is provided by higher layers in SIB2.  Set to 21dBm for 2x40W MIMO cell.

8. referenceSignalPower Downlink reference-signal EPRE (Energy Per Resource Element). Why 21dBm? 10MHz LTE carrier -> 50 RB 1 RB = 12 sub carriers (12 symbols) Assuming 40W RDLT, then 40 [W]/50 [RB]= 0.8 [W/RB] Pwr per symbol = 0.8 [W]/12 [symbols] = 0.0667 [W]/[symbol] 0.0667 [W] = 18.24 [dBm] 2 TX antennas = 18.24 [dBm] + 3 [dB] = 21.24 [dBm] “The downlink reference-signal EPRE can be derived from the downlink reference-signal transmit power given by the parameter Reference-signal-power provided by higher layers. The downlink reference-signal transmit power is defined as the linear average over the power contributions (in [W]) of all resource elements that carry cell-specific reference signals within the operating system bandwidth.” (2x2 MIMO: 4 RS out of 14 in every 3rd sub-carrier 9.6% of total power 46dBm)

9. 3 dB Power Boost for RS R0 off to limit interference R1 off to limit interference RS power increases by 3dB due to non used RE power added to RS, when RS of other antenna is transmitted.

10. Open loop power control example (PUSCH) P0-nominalPUSCH = -103dBm referenceSignalPower = 21dBm UE max Pwr = 22.5dBm Number of Resource Blocks = 1 RSRP = -100dBm 1

11. UL Power control (PUSCH) – Open loop UE transmit power for PUSCH transmission ：  is the maximum allowable UE power;  M is the number of scheduled resource blocks; (broadcasted on PDCCH)  PL is the downlink pathloss, estimated by UE. The UE can use measurements of DL pathloss for estimation of UL pathloss. (Open-loop)  is to enable fractional pathloss compensation;  P O_PUSCH set according to SINR target. SINR target is a parameter set to fulfill the HARQ operating Point (OPP) quality requirements using the most efficient MCS. P O_PUSCH is broadcasted on BCCH SIB2  is a Transport Format (TF) specific offset.

12. UL Power control (PUSCH) – Closed loop  The function f(i) can either be cumulative or absolute (SIB2 accumulationEnabled).  In case of a cumulative function (accumulation enabled by higher layers):  In case of absolute function (accumulation disabled by higher layers):  is UE specific power adjustment included in the uplink scheduling grant or in special TPC_PUSCH messages on the PDCCH. It enforces the open loop PSD target and is updated fast enough to compensate for the slow fading. “Scheduler Delay”

13. TPC Command Accumulated [dB] Absolute [dB] 0-4 10 211 334 UL Power control (PUSCH) – Closed loop is set according to:

14. UL Power Control (PUCCH) – Open loop UE transmit power for PUCCH transmission ：  is the maximum allowable UE power;  PL is the downlink pathloss, estimated by UE. The UE can use measurements of DL pathloss for estimation of UL pathloss. (Open-loop)  h(n) is a PUCCH format dependent value where n(cqi) corresponds to the number of information bits for the CQI, and n(harq) the number of HARQ bits. For PUCCH formats 1, 1a and 1b, h(n) is always 0. For PUCCH format 2, h(n) is 0 for normal cyclic prefix and n(cqi) 4.  corresponds to a PUCCH format offset. Provided by higher layers.

15. UL Power Control (PUCCH) – Closed loop  g(i) is the current PUCCH power control adjustment state, similar as PUSCH (accumulation enabled), using parameter to calculate.

16. UL Power Control (PUCCH) – Closed loop TPC CommandAccumulated [dB] 0 10 21 33  The open loop part controls P O_PUCCH, and the closed loop part controls g(i). This function works much the same way as for PUSCH, except the TPC commands for PUCCH can be transmitted in the downlink scheduling assignments, and without any uplink grant.

17. CLPC Testing The test is done in downtown Bellevue loop with 20 Mbps UL UDP data. Following slides show comparative analysis between CLPC active and inactive in the same graph.

18. UL Throughput Comparison

19. UE TX Power Comparison

20. CLPC Testing Observations CLPC functionality has reduced the required power from the UEs significantly while the throughput figures are quite close to each other.

21. Higher Layer Filtered RSRP (filterCoefficientEUtraRSRP & filterCoefficientEUtraRSRQ) RSRP filtering k=8

22. EUtranCellFDD PM Counters pmRadioRecInterferencePwr The measured Noise and Interference Power on PUSCH, according to 36.214 PDF ranges: [0]: N+I <= -121 [1]: -121 < N+I <= -120 [2]: -120 < N+I <= -119 [3]: -119 < N+I <= -118 [4]: -118 < N+I <= -117 [5]: -117 < N+I <= -116 [6]: -116 < N+I <= -115 [7]: -115 < N+I <= -114 [8]: -114< N+I <= -113 [9]: -113 < N+I <= -112 [10]: -112 < N+I <= -108 [11]: -108 < N+I <= -104 [12]: -104 < N+I <= -100 [13]: -100 < N+I <= -96 [14]: -96 < N+I <= -92 [15]: -92 < N+I Condition: An average value is measured on a TTI basis Unit: dBm/PRB Report from 2011-02-16 14:00 UTC to 2011-02-16 14:14 UTC Time Object pmRadioRecInterferencePwr 14:00 EUtranCellFDD=172169_1 5664,880660,8739,3020,1372,364,21,0,0,0,0,0,0,0,0,0 14:00 EUtranCellFDD=172169_2 617247,282277,309,7,0,0,0,0,0,0,0,0,0,0,0,0 14:00 EUtranCellFDD=172169_3 761490,138350,0,0,0,0,0,0,0,0,0,0,0,0,0,0

23. EUtranCellFDD PM Counters pmRadioTbsPwrRestricted The number of Transport Blocks on MAC level scheduled in uplink where the UE was considered to be power limited. pmRadioTbsPwrUnrestricted The number of Transport Blocks on MAC level scheduled in uplink where the UE was NOT considered to be power limited. Condition: A Transport Block is considered to be power limited when the estimated required transmit power is higher than the UE maximum transmit power. Report from 2011-02-16 13:00 UTC to 2011-02-16 13:14 UTC Time Object pmRadioTbsPwrRestricted pmRadioTbsPwrUnrestricted 13:00 EUtranCellFDD=172169_1 32 1630 13:00 EUtranCellFDD=172169_2 46 2376 13:00 EUtranCellFDD=172169_3 19 31

25. DL-PC

30. DL-PC:PC ON PDCCH

34. Thank You