Extended UL MIMO Power Classes for Multi-Chain PUSCH
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Solution Overview
Problem
Non-coherent UL MIMO UEs face challenges in transmitting full power on all transmit chains while meeting single port operation power requirements, leading to reduced coverage and inefficient PA operation.
Innovation Solution
A UE configured for UL MIMO indicates support for a first power class and can transmit a single layer PUSCH on one antenna port at a first power level, and an N-layer PUSCH on N antenna ports at a second power level, with the second power level being greater than the first, allowing for increased transmission power without upgrading PAs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If non-coherent UL MIMO UEs transmit full power on all transmit chains, then transmission power is increased, but single port operation power requirements are violated
Solution Approach 1:
The patent introduces dynamic power scaling where the UE adjusts transmit power based on the number of active transmit chains. When N>1 transmit chains are used, the UE scales power by factor N to achieve N× power output. This dynamic adjustment allows the UE to meet both single-port power requirements and multi-chain power utilization, resolving the contradiction between transmitting full power and complying with power class limits.
2Ease of manufacture
If UEs use lower power PAs to reduce cost, then device cost is reduced, but coherent transmission is required to maintain power efficiency
Solution Approach 1:
The patent enables UEs to use lower-power, less expensive PAs by distributing power across multiple transmit chains. Instead of requiring one high-power PA for coherent transmission, the system uses multiple lower-power PAs that can be more easily manufactured. The power scaling mechanism ensures that the sum of powers from all chains meets the required output, allowing cost-effective PA selection without compromising performance.
3Power
If UEs transmit on multiple transmit chains with N PAs rated at Pmax/N, then power distribution is optimized, but correlated antennas reduce combined power output
Solution Approach 1:
The patent changes the power parameter from individual chain power Pmax/N to total scaled power N×Pmax/N=Pmax. By introducing the scaling factor N, the system accounts for antenna correlation effects and ensures that the combined power output from multiple chains meets the required Pmax. This parameter adjustment allows flexible power distribution across correlated or uncorrelated antennas while maintaining reliable power output.
Data Source
AI summary
An extended power class for Uplink (UL) Multiple Input Multiple Output (MIMO) communications is provided. In this regard, a User Equipment (UE) configured to UL MIMO can indicate support for a first power class corresponding to a first power level. The UE can transmit a single layer Physical UL Shared Channel (PUSCH) on one antenna port at a power that is at most a first power level corresponding to the first power class. The UE can also transmit an N-layer PUSCH on N antenna ports at a second power level greater than the first power level. With the extended power class, UEs are able to deliver higher power signals without increasing the maximum power of their Power Amplifiers (PAs). This greater power can lead to better user experience, less battery drain, and higher network capacity.