5G • RAN

MPR

Maximum Power Reduction

Standardized power backoff permitted on UE transmitters to prevent out-of-band emissions caused by high-order modulation.

Technical Explanation

High-order modulations (e.g. 64QAM, 256QAM) and wideband multi-carrier allocations have high Peak-to-Average Power Ratios. To prevent transmitter nonlinearity from spilling energy into adjacent frequency bands, 3GPP standards allow the UE to reduce its maximum output power (P_CMAX) by an allowed MPR value (e.g. 1 to 3 dB).

Key Functions

  • Permits controlled power amplifier backoff to preserve linearity
  • Prevents adjacent channel leakage ratio (ACLR) violations
  • Defined in 3GPP RF specifications based on modulation and PRB allocation
Specifications
3GPP TS 38.101-1, TS 38.101-2
Interfaces
Uu

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