CSI Reporting Under EIRP Constraints

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Solution Overview

Problem

Wireless communication systems face challenges in accurately reporting channel state information (CSI) under effective isotropic radiated power (EIRP) constraints, which affect network performance and uplink power optimization due to regulatory power limits and varying transmission modes.

Innovation Solution

The implementation of different CSI measurement and reporting techniques based on operating modes, including explicit signaling and path loss measurements, with base stations employing scaling factors, modifying modulation and coding schemes, and selecting antenna ports to compensate for EIRP constraints, allowing for accurate CSI reporting and optimized power management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the base station operates under EIRP constraints with reduced transmit power, then regulatory compliance is achieved, but CSI reporting accuracy deteriorates

Engineering Contradiction:

Improveregulatory power limit complianceVSAvoidCSI reporting accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The base station dynamically switches between normal operating mode and EIRP-constrained operating mode based on current regulatory requirements and channel conditions. In EIRP-constrained mode, the system applies power backoff and activates alternative transmission schemes such as transmit diversity and reduced MCS, allowing adaptive response to power constraints while maintaining communication quality

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes multiple transmission parameters simultaneously when EIRP constraints are detected: reduces transmit power by applying backoff, lowers modulation and coding scheme (MCS) to more robust levels, increases transmit diversity order, and adjusts antenna port selection. These coordinated parameter changes compensate for power reduction and maintain CSI reporting accuracy

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the base station applies power backoff to meet EIRP limits, then regulatory compliance is achieved, but uplink power optimization deteriorates

Engineering Contradiction:

ImproveEIRP limit complianceVSAvoiduplink power efficiency

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The UE measures downlink path loss and provides feedback to the base station. The base station uses this feedback along with its knowledge of EIRP constraints to calculate appropriate uplink power backoff values. This closed-loop feedback mechanism ensures that uplink power is optimized to match the actual downlink power conditions, preventing both power waste and insufficient uplink power

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The base station proactively signals EIRP constraint information and scaling factors to the UE before uplink transmission occurs. This allows the UE to pre-calculate the appropriate uplink power level, avoiding both excessive power consumption and transmission failures. The preliminary signaling includes indications of power backoff values and alternative transmission schemes

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If the base station uses alternative transmission schemes like transmit diversity, then EIRP constraint compliance is maintained, but transmission efficiency deteriorates

Engineering Contradiction:

Improvepower spectral density limit complianceVSAvoidtransmission efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The base station dynamically selects among multiple transmission schemes based on current channel conditions and EIRP constraint severity. When EIRP constraints are active, it can switch between transmit diversity, reduced MCS, antenna port selection, and other schemes. This dynamic selection allows the system to optimize transmission efficiency within the constraints by choosing the most appropriate scheme for each situation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system adjusts multiple transmission parameters in coordination: changes modulation order and coding rate (MCS), modifies antenna port allocation and precoding, adjusts transport block size, and selects appropriate MIMO modes. These coordinated parameter changes allow the system to maintain reasonable transmission efficiency while complying with EIRP and PSD limits

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3824567B1Transmission of CSI report to base station for EIRP-constrained transmissions

Publication Date: 2023.12.27 QUALCOMM INC

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AI summary

A method for wireless communications at a user equipment (115-b),UE, comprises: receiving a downlink transmission from a base station (105-b) including a channel state information, CSI, reporting mode (315); selecting, based at least in part on the received downlink transmission, a channel state information CSI computation mode for the wireless channel, wherein the CSI computation mode is based at least in part on an effective isotropic radiated power, EIRP, constraint (325); measuring a set of one or more CSI reference signals (330), CSI-RSs, from the base station to obtain a CSI measurement (335); and transmitting (345) a CSI report to the base station based at least in part on the selected CSI computation mode (340) and the CSI measurement (335).