Transmission power management
Certain examples of the present disclosure relate to a User Equipment, UE, ( 110 ) comprising means for: determining a first total amount of energy (E Tx(TW1) ) that has been transmitted by the UE within a first time window (TW1); and determining a first transmission power (P maxTx(i) ) that is allowed for a transmission (Tx (i) ) by the UE within the first time window, TW1 wherein the first transmission power is determined based, at least in part, on the first total amount of energy (E Tx(TW1) ) that has been transmitted by the UE within the first time window (TW1).
1 . A User Equipment (UE), comprising:
at least one processor; and
at least one memory including instructions,
wherein the at least one memory and the instructions are configured to, with the at least one processor, cause the user equipment to perform operations comprising:
receive, from a gNodeB (gNB) through a dedicated Radio Resource Control (RRC) signalling, a set of configuration parameters for an energy-based power boost calculation, wherein the set of configuration parameters comprises:
a first time window (TW1) comprising N slots, wherein each of the N slots comprises up to 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols,
a second time window (TW2), within the first time window, comprising M slots, wherein each of the M slots comprises up to the 14 OFDM symbols, and wherein a number of M slots is less than a number of N slots,
a first parameter value (X1) to enable an adjustment of sharing of an available transmission energy for the first time window over time, wherein the first parameter value (X1) is one of: equal to the number of N slots, less than the number of N slots, or larger than the number of N slots,
a second parameter value (X2) to enable an adjustment of sharing of an available transmission energy for the second time window over time, wherein the second parameter value (X2) is one of: equal to the number of M slots, less than the number of M slots, or larger than the number of M slots,
a first allowed transmission energy permitted over the first time window,
a second allowed transmission energy permitted over the second time window, and
a predetermined maximum transmission power permitted for the UE based on Specific Absorption Rate (SAR) and Equivalent Isotropic Radiated Power (EIRP) regulatory limits;
determine a first total amount of energy transmitted by the UE within the first time window prior to a current transmission in an i th slot of the first time window, wherein the first total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of N slots within the first time window prior to the current transmission in the i th slot;
determine a second total amount of energy transmitted by the UE within the second time window prior to the current transmission in the i th slot, wherein the second total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of M slots within the second time window prior to the current transmission in the i th slot;
determine a number of symbols to be transmitted in the ith slot; and
determine a first transmission power allowed for the current transmission in the ith slot of the first time window, by;
calculating a first available transmission energy available for the current transmission in the i th slot with respect to the first time window as a difference between the first allowed transmission energy and the determined first total amount of energy and dividing the difference between the first allowed transmission energy and the determined first total amount of energy by the first parameter value;
calculating a second available transmission energy available for the current transmission in the i th slot with respect to the second time window as a difference between the second allowed transmission energy and the determined second total amount of energy and dividing the difference between the second allowed transmission energy and the determined second total amount of energy by the second parameter value;
determining a final available transmission energy as the minimum of the first available transmission energy and the second available transmission energy;
calculating a third transmission power for the current transmission in the i th slot by dividing the determined final available transmission energy by the determined number of symbols to be transmitted in the i th slot; and
determining the first transmission power as a minimum of the third transmission power and the predetermined maximum transmission power.
2 . The UE of claim 1 , wherein the determination of the first total amount of energy and the second total amount of energy is performed iteratively using an Infinite Impulse Response (IIR) filter.
3 . The UE of claim 2 , wherein determining the first total amount of energy transmitted within the first time window comprises, for each of the N slots prior to the ith slot, determining a respective transmission duration based on a respective number of OFDM symbols transmitted in the slot, and accumulating energy as a product of slot transmit power and the determined transmission duration.
4 . The UE of claim 3 , wherein the first allowed transmission energy permitted over the first time window is computed based on an assumed contiguous uplink transmission over the N slots at a nominal transmit power associated with a power class of the UE.
5 . The UE of claim 4 , wherein the second allowed transmission energy permitted over the second time window is configured as a predefined fraction of the first allowed transmission energy permitted over the first time window.
6 . The UE of claim 5 , wherein determining the first total amount of energy transmitted by the UE within the first time window is performed using an iterative Infinite Impulse Response (IIR) filter having a first decay coefficient, and wherein determining the second total amount of energy transmitted by the UE within the second time window is performed using an iterative IIR filter having a second decay coefficient greater than the first decay coefficient.
7 . The UE of claim 6 , wherein the ith slot is within the second time window, and wherein the second time window is a trailing sub-window of the first time window that is temporally aligned with the ith slot.
8 . The UE of claim 7 , further comprising updating, based on the determined first transmission power, a configured maximum output power parameter used by an uplink power control procedure for at least one of Physical Uplink Shared Channel (PUSCH) transmission or Physical Uplink Control Channel (PUCCH) transmission.
9 . The UE of claim 8 , further comprising transmitting, to the gNB, a report indicative of at least one of (i) the determined first total amount of energy for the first time window, (ii) the determined first transmission power for the ith slot, or (iii) a request to adjust a maximum duty cycle for the UE, wherein the report is carried in at least one of a Power Headroom Report (PHR) Medium Access Control Control Element (MAC CE) or a Buffer Status Report (BSR) MAC CE.
10 . The UE of claim 9 , wherein the predetermined maximum transmission power permitted for the UE is applied as an Effective Isotropic Radiated Power (EIRP) cap by adding an antenna/beamforming gain to the third transmission power prior to applying the minimum operation.
11 . The UE of claim 10 , further comprising determining the number of symbols to be transmitted in the ith slot based on uplink scheduling information received from the gNB, and performing the energy-based power boost calculation at an OFDM-symbol granularity to derive the first transmission power for the current transmission.
12 . A method for a User Equipment (UE), the method comprising:
receiving, from a gNodeB (gNB) through a dedicated Radio Resource Control (RRC) signalling, a set of configuration parameters for an energy-based power boost calculation, wherein the set of configuration parameters comprises:
a first time window (TW1) comprising N slots, wherein each of the N slots comprises up to 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols,
a second time window (TW2), within the first time window, comprising M slots, wherein each of the M slots comprises up to the 14 OFDM symbols, and wherein a number of M slots is less than a number of N slots,
a first parameter value (X) to enable an adjustment of sharing of an available transmission energy for the first time window over time, wherein the first parameter value (X1) is one of: equal to the number of N slots, less than the number of N slots, or larger than the number of N slots,
a second parameter value (X2) to enable an adjustment of sharing of an available transmission energy for the second time window over time, wherein a the second parameter value (X2) is one of: equal to the number of M slots, less than the number of M slots, or larger than the number of M slots,
a first allowed transmission energy (E allowedTx(TW1) ) permitted over the first time window,
a second allowed transmission energy (E allowedTx(TW2) ) permitted over the second time window, and
a predetermined maximum transmission power (P regulated ) permitted for the UE based on Specific Absorption Rate (SAR) and Equivalent Isotropic Radiated Power (EIRP) regulatory limits;
determining a first total amount of energy (E Tx(TW1) ) transmitted by the UE within the first time window prior to a current transmission in an i th slot of the first time window, wherein the first total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of the N slots within the first time window prior to the current transmission in the i th slot;
determining a second total amount of energy (E Tx(TW2) ) transmitted by the UE within the second time window prior to the current transmission in the i th slot, wherein the second total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of the M slots within the second time window prior to the current transmission in the i th slot;
determining a number of symbols to be transmitted in the ith slot; and
determining a first transmission power (P maxTx(i) ) allowed for the current transmission in the i th slot of the first time window, by;
calculating a first available transmission energy (E available(i) ) available for the current transmission in the i th slot with respect to the first time window as a difference between the first allowed transmission energy (E allowedTx(TW1) ) and the determined first total amount of energy (E Tx(TW1) ) and dividing the difference between the first allowed transmission energy (E allowedTx(TW1) ) and the determined first total amount of energy (E Tx(TW1) ) by the first parameter value (X);
calculating a second available transmission energy (E available(i)TW2 ) available for the current transmission in the i th slot with respect to the second time window as a difference between the second allowed transmission energy (E allowedTx(TW2) ) and the determined second total amount of energy (E Tx(TW2) ) and dividing the difference between the second allowed transmission energy (E allowedTx(TW2) ) and the determined second total amount of energy (E Tx(TW2) ) by the second parameter value (X 2 );
determining a final available transmission energy as the minimum of the first available transmission energy (E available(i) ) and the second available transmission energy (E available(i)TW2 );
calculating a third transmission power for the current transmission in the i th slot by dividing the determined final available transmission energy by the determined number of symbols to be transmitted in the i th slot; and
determining the first transmission power as a minimum of the third transmission power and the predetermined maximum transmission power.
13 . A non-transitory computer readable medium comprising computer program instructions for a User Equipment (UE) which, when executed by an apparatus, cause the UE at least to perform operations comprising:
receiving, from a gNodeB (gNB) through a dedicated Radio Resource Control (RRC) signalling, a set of configuration parameters for an energy-based power boost calculation, wherein the set of configuration parameters comprises:
a first time window (TW1) comprising N slots, wherein each of the N slots comprises up to 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols,
a second time window (TW2), within the first time window, comprising M slots, wherein each of the M slots comprises up to the 14 OFDM symbols, and wherein a number of M slots is less than a number of N slots,
a first parameter value (X) to enable an adjustment of sharing of an available transmission energy for the first time window over time, wherein a the first parameter value (X1) is one of: equal to the number of N slots, less than the number of N slots, or larger than the number of N slots,
a second parameter value (X2) to enable an adjustment of sharing of an available transmission energy for the second time window over time, wherein the second parameter value (X2) is one of: equal to the number of M slots, less than the number of M slots, or larger than the number of M slots,
a first allowed transmission energy (E allowedTx(TW1) ) permitted over the first time window,
a second allowed transmission energy (E allowedTx(TW2) ) permitted over the second time window, and
a predetermined maximum transmission power (P regulated ) permitted for the UE based on Specific Absorption Rate (SAR) and Equivalent Isotropic Radiated Power (EIRP) regulatory limits;
determining a first total amount of energy (E Tx(TW1) ) transmitted by the UE within the first time window prior to a current transmission in an i th slot of the first time window, wherein the first total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of the N slots within the first time window prior to the current transmission in the i th slot;
determining a second total amount of energy (E Tx(TW2) ) transmitted by the UE within the second time window prior to the current transmission in the i th slot, wherein the second total amount of energy is calculated as a sum of energy transmitted over the OFDM symbols in each of the M slots within the second time window prior to the current transmission in the i th slot;
determining a number of symbols to be transmitted in the ith slot; and
determining a first transmission power (P maxTx(i) ) allowed for the current transmission in the i th slot of the first time window, by;
calculating a first available transmission energy (E available(i) ) available for the current transmission in the i th slot with respect to the first time window as a difference between the first allowed transmission energy (E allowedTx(TW1) ) and the determined first total amount of energy (E Tx(TW1) ) and dividing the difference between the first allowed transmission energy (E allowedTx(TW1) ) and the determined first total amount of energy (E Tx(TW1) ) by the first parameter value (X);
calculating a second available transmission energy (E available(i)TW2 ) available for the current transmission in the i th slot with respect to the second time window as a difference between the second allowed transmission energy (E allowedTx(TW2) ) and the determined second total amount of energy and dividing the difference between the second allowed transmission energy (E allowedTx(TW2) ) and the determined second total amount of energy (E Tx(TW2) ) by the second parameter value (X 2 );
determining a final available transmission energy as the minimum of the first available transmission energy (E available(i) ) and the second available transmission energy (E available(i)TW2 );
calculating a third transmission power for the current transmission in the i th slot by dividing the determined final available transmission energy by the determined number of symbols to be transmitted in the i th slot; and
determining the first transmission power as a minimum of the third transmission power and the predetermined maximum transmission power.