Dynamic Transmit Diversity Fallback for 5G MIMO Scheduling
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Solution Overview
Problem
Current mobile and wireless telecommunication systems, particularly in 5G and NR, lack transmit diversity fallback options for transmission modes 9 and 10 during shorter transmission time intervals (TTIs), leading to inadequate reliability and performance in scenarios without accurate channel state information or requiring high reliability transmissions.
Innovation Solution
Implementing a dynamic transmit diversity fallback method that utilizes unused signaling states or bits in the DCI (Downlink Control Information) to enable transmit diversity for TM9 and TM10, using modified mapping tables and RRC (Radio Resource Control) configurations to support up to 2 or 4 MIMO layers, depending on UE capabilities, without increasing DCI signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmit diversity fallback is implemented for TM9 and TM10 using modified mapping tables, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameters of the mapping table by repurposing existing DCI signaling fields (antenna port, scrambling identity, and number of layers indication) to indicate transmit diversity fallback. This allows the system to switch between transmission modes by modifying the interpretation of existing parameters rather than adding new signaling elements, thereby improving reliability without significantly increasing device complexity
Solution Approach 2:
The patent makes the existing DCI signaling fields serve multiple functions: they simultaneously indicate MIMO layer configuration and transmit diversity fallback status. This multi-functionality allows the system to achieve transmit diversity fallback capability without adding dedicated signaling bits, resolving the contradiction between reliability improvement and device complexity
2Reliability
If transmit diversity fallback is enabled for shorter TTI, then reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent reinterprets existing DCI parameters to convey transmit diversity fallback information. By changing how the antenna port, scrambling identity, and number of layers indication fields are interpreted rather than adding new fields, the patent achieves reliable transmit diversity fallback signaling without increasing the overall DCI signaling overhead for shorter TTI
3Adaptability or versatility
If dynamic fallback to transmit diversity is implemented, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic fallback capability where the transmission mode can be switched between TM9/TM10 and transmit diversity on a per-scheduling-instance basis. The network can dynamically indicate fallback by setting specific values in the repurposed DCI fields, allowing flexible adaptation to channel conditions without requiring complex pre-configured fallback mechanisms
Solution Approach 2:
The patent achieves dynamic adaptability by modifying the interpretation of existing DCI parameters. When specific values are detected in the antenna port, scrambling identity, or number of layers indication fields, the UE interprets this as a fallback instruction. This parameter-based dynamic control provides transmission mode flexibility without adding complex signaling protocols
Data Source
AI summary
Systems, methods, apparatuses, and computer program products for dynamic transmit diversity fallback are provided. One method may include configuring a user equipment with a maximum number of multiple-input multiple-output (MIMO) layers used for transmission mode 9 or transmission mode 10 scheduling, and performing, by a network node, at least one of transmission mode 9 or transmission mode 10 scheduling. The configuring may include indicating to the user equipment to use a modified mapping table providing transmit diversity fallback for the at least one of transmission mode 9 or transmission mode 10 scheduling.