Implicit Waveform Switching via Hybrid MCS Table
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Solution Overview
Problem
Wireless communication systems face challenges in dynamically adapting waveform configurations to changing channel conditions, leading to inefficiencies and link interruptions due to high latency in reconfiguring waveforms, especially when user equipment (UE) moves between cell edges or experiences varying signal-to-noise ratios (SNR).
Innovation Solution
The technique involves implicitly signaling a switch between waveform configurations based on an indicated modulation coding scheme (MCS) index, using a hybrid MCS table that includes indexes for both configurations, allowing the UE to select the appropriate waveform for uplink transmissions based on received resources and MCS indices, thereby reducing reconfiguration latency and improving communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If explicit reconfiguration signaling is used to switch waveform configurations, then waveform switching capability is achieved, but reconfiguration latency increases and link interruptions occur
Solution Approach 1:
The UE autonomously determines the waveform configuration by comparing the received MCS index with a pre-configured threshold, eliminating the need for explicit reconfiguration signaling from the base station. This self-service mechanism enables immediate waveform switching without waiting for network commands, thereby reducing reconfiguration latency and avoiding link interruptions.
Solution Approach 2:
The patent changes the interpretation parameter of the MCS index from its traditional role in modulation and coding selection to also serve as a waveform configuration indicator. By comparing the MCS index value against a threshold, the system dynamically switches between different waveform configurations (e.g., CP-OFDM and DFT-S-OFDM) without requiring additional signaling parameters, thus achieving fast adaptation with minimal latency.
2Reliability
If waveform configuration is changed to adapt to changing channel conditions, then communication quality improves, but reconfiguration latency and link interruptions increase
Solution Approach 1:
The UE autonomously adapts waveform configuration by self-evaluating the received MCS index against a threshold, enabling immediate response to changing channel conditions without network intervention. This self-service approach ensures communication quality optimization while avoiding the latency and link interruptions associated with traditional explicit reconfiguration signaling.
Solution Approach 2:
The waveform configuration becomes dynamic and adaptable to real-time channel conditions through the MCS index comparison mechanism. The system can seamlessly switch between different waveform types based on current transmission conditions, enabling continuous optimization of communication quality without the rigidity of pre-configured waveform settings.
3Loss of time
If a hybrid MCS table is used for implicit waveform indication, then reconfiguration latency is reduced, but system complexity increases
Solution Approach 1:
The hybrid MCS table serves multiple functions simultaneously: it indicates both the traditional modulation and coding parameters and the waveform configuration. By making the MCS index multi-functional, the system eliminates the need for separate waveform indication signaling, thereby reducing reconfiguration latency while the added complexity is confined to the standardized table structure rather than runtime operations.
Solution Approach 2:
The MCS index parameter is enhanced to carry additional information about waveform configuration alongside its traditional modulation and coding indications. This parameter expansion allows the system to convey multiple configuration aspects through a single index value, reducing signaling overhead and latency while managing complexity through standardized parameter definitions.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described to switch between waveform configurations based on an indicated modulation coding scheme (MCS) such that waveform switching may be signaled implicitly. A base station may configure a user equipment (UE) with a hybrid MCS table including MCS indexes associated with a first waveform configuration and MCS indexes associated with a second waveform configuration. The base station may schedule resources for an uplink transmission for the UE and may indicate an MCS index associated with the uplink transmission, using index from the MCS table. The UE may select a waveform configuration for the uplink transmission based on the MCS index. For example, the UE may compare the MCS index with a threshold MCS index of the hybrid MCS table and determine a waveform configuration associated with the MCS index based on whether the MCS index falls above or below the threshold.