DMRS Configuration for Variable-Length Time Units
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Solution Overview
Problem
Future radio communication systems, such as LTE Rel. 14 or 5G, require demodulation reference signals (DMRS) suitable for variable-length transmission periods, as existing LTE systems with fixed 1-ms subframes may not adequately demodulate data channels with variable lengths.
Innovation Solution
The solution involves a transmitting and receiving apparatus that applies the same DMRS configuration to both fixed and variable-length time units, with the DMRS being placed in the beginning part of the data field for non-slot-based scheduling to ensure accurate demodulation and channel estimation, and controlling the number of DMRSs based on slot-based scheduling to reserve resources for data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the same DMRS configuration is applied to both fixed and variable-length time units, then demodulation accuracy is improved, but resource flexibility is reduced
Solution Approach 1:
The patent applies different DMRS configuration parameters specifically to variable-length time units while maintaining standard configurations for fixed-length units. This allows the system to optimize demodulation accuracy for variable-length transmissions without compromising the efficiency of standard fixed-length transmissions, thereby resolving the contradiction between demodulation accuracy and resource flexibility.
Solution Approach 2:
The patent introduces dynamic DMRS configuration that adapts to the actual transmission time unit length. The control section dynamically selects appropriate DMRS parameters based on whether the transmission uses fixed or variable length time units, enabling the system to maintain high demodulation accuracy across different transmission scenarios while preserving resource allocation flexibility.
2Measurement precision
If DMRS are placed in the beginning part of the data field for non-slot-based scheduling, then channel estimation accuracy is improved, but data transmission efficiency is reduced
Solution Approach 1:
The patent applies DMRS only to the necessary portion of variable-length time units rather than uniformly across all transmissions. By placing DMRS in the beginning part specifically for non-slot-based scheduling while using standard placement for slot-based scheduling, the system achieves adequate channel estimation accuracy for variable-length transmissions without excessively reducing data transmission efficiency across all transmission types.
Solution Approach 2:
The patent changes the DMRS placement parameter based on the scheduling type. For non-slot-based scheduling with variable-length time units, DMRS are placed in the beginning part of the data field. For slot-based scheduling with fixed-length time units, standard DMRS placement is maintained. This parameter change allows the system to optimize channel estimation for variable-length transmissions while preserving data transmission efficiency for standard transmissions.
3Loss of energy
If the number of DMRSs is controlled based on slot-based scheduling, then resource overhead is reduced, but demodulation reliability for variable-length transmissions is worsened
Solution Approach 1:
The patent segments the DMRS allocation strategy into two parts: slot-based scheduling and non-slot-based scheduling. For slot-based scheduling, the number of DMRSs is controlled to reduce resource overhead. For non-slot-based scheduling with variable-length time units, additional DMRSs are allocated to ensure demodulation reliability. This segmentation allows the system to optimize resource overhead for standard transmissions while ensuring reliability for variable-length transmissions.
Solution Approach 2:
The patent applies enhanced DMRS allocation specifically to variable-length time units in non-slot-based scheduling while maintaining reduced DMRS allocation for fixed-length slot-based scheduling. This localized quality enhancement ensures that demodulation reliability is improved where needed (variable-length transmissions) without increasing resource overhead for all transmissions.
Data Source
AI summary
A receiving apparatus is disclosed including a receiver that receives a downlink shared channel using a first allocation that supports a first allocation interval and a first allocation start symbol, and a second allocation that supports a second allocation interval and a second allocation start symbol, the first allocation interval and the first allocation start symbol being different from the second allocation interval and the second allocation start symbol, respectively; and a processor that applies a reference signal configuration type, notified by a higher layer, to a first reference signal used in a downlink shared channel that applies the first allocation, and to a second reference signal used in a downlink shared channel that applies the second allocation. In other aspects, a transmitting apparatus is also disclosed.