UE Capability Indications for Modulation Constraints
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Solution Overview
Problem
Wireless communication systems face challenges in supporting high-order modulation due to constraints on data rates and error vector magnitude (EVM) in higher frequency bands, such as millimeter wave (mmW) frequencies, which affect the reliability of data transmissions.
Innovation Solution
User equipment (UE) capability indications are enhanced to report constraints on supported modulation orders, allowing for the use of lower modulation orders in challenging frequency bands, thereby reducing error impacts and maintaining spectral efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order modulation (e.g., 256QAM) is used in higher frequency bands (mmW), then data transmission rate is improved, but error vector magnitude (EVM) increases and reliability deteriorates
Solution Approach 1:
The patent implements dynamic modulation order adjustment where the UE reports capability constraints to the network, enabling the system to adaptively select between high-order modulation (256QAM) for high data rates and lower modulation orders (64QAM, QPSK) for reliable transmission in mmW bands, rather than using a fixed modulation scheme
Solution Approach 2:
The patent changes the modulation order parameter based on frequency band and UE capability constraints. The network receives capability indications from the UE and adjusts modulation parameters accordingly, selecting appropriate modulation orders (e.g., 256QAM, 64QAM, QPSK) to balance data rate and reliability requirements
2Productivity
If high-order modulation is used, then spectral efficiency is improved, but constraints on data rate and EVM in higher frequency bands worsen
Solution Approach 1:
The patent applies different modulation orders to different frequency bands based on local conditions. The UE capability indication allows the network to apply high-order modulation (256QAM) to frequency bands with favorable characteristics while using lower modulation orders (64QAM, QPSK) to bands with EVM constraints, optimizing spectral efficiency locally rather than uniformly across all bands
Solution Approach 2:
The patent segments the frequency spectrum into different bands with different modulation characteristics. The capability indication mechanism allows the network to identify which frequency bands support high-order modulation and which require lower modulation orders, enabling segmented transmission strategies that address EVM constraints in specific bands while maintaining high spectral efficiency in others
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described that provide for a user equipment (UE) capability indication that indicates one or more constraints associated with a supported modulation order. In some cases, the UE capability indication may indicate that the UE supports a particular modulation order, but has a capacity constraint such that an associated data rate is limited to a data rate associated with a lower modulation order. In some cases, one or more frequency bands may be mapped to a UE constraint.