5G NR Demodulation Reference Signal Resource Allocation for NOMA
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Solution Overview
Problem
The conventional 5G NR DMRS method is inadequate in supporting a sufficient number of user equipment connections due to its limited capacity to transmit demodulation reference signals on the same time domain resource, particularly in NOMA environments where higher efficiency and reliability are required.
Innovation Solution
A resource allocation method for demodulation reference signals that determines an optimal allocating mode and generates parameters to enable the transmission of multiple demodulation reference signals on the same time domain resource, allowing them to be distinguished on the same time frequency resource, thereby supporting a larger number of user equipment connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional transmission mode is used for NR DMRS, then up to twelve ports (user equipment) can be supported on the same time domain resource, but this capacity is far from enough in NOMA scenarios requiring higher connections density
Solution Approach 1:
The patent introduces a new dimension for DMRS port differentiation by enabling multiple DMRS ports to share the same time-frequency resources through spatial multiplexing and code domain separation. This allows exceeding the conventional limit of twelve ports by utilizing additional spatial and coding dimensions rather than being constrained by traditional time-frequency resource allocation alone
Solution Approach 2:
The patent changes key parameters including enabling up to thirty DMRS ports per bandwidth part, modifying the relationship between DMRS ports and CDM groups, and adjusting the maximum number of CDM groups without data to support higher port counts. These parameter changes fundamentally increase the system's capacity to support NOMA scenarios with higher connection density
2Quantity of substance
If more demodulation reference signals are transmitted on the same time frequency resource, then more user equipment can be supported, but the complexity of resource allocation and signal differentiation increases
Solution Approach 1:
The patent segments the DMRS resources by introducing CDM (Code Division Multiplexing) groups that divide the available ports into distinct groups. Each CDM group uses orthogonal cover codes to separate different ports, allowing multiple DMRS signals to coexist on the same time-frequency resources without interference. This segmentation manages complexity by organizing ports into structured groups rather than allowing unmanaged overlap
Solution Approach 2:
The patent uses orthogonal cover codes as an intermediary mechanism to enable differentiation between multiple DMRS ports sharing the same time-frequency resources. These codes act as mediators that allow the system to support more ports while maintaining signal distinguishability, effectively managing the complexity through standardized code-based separation
Data Source
AI summary
Disclosed are a resource allocation method for demodulation reference signals and a base station. The resource allocation method for demodulation reference signals executed by the base station includes: determining an allocation method for a resource required for transmitting a plurality of demodulation reference signals and a parameter for generating the plurality of demodulation reference signals, the plurality of demodulation reference signals respectively corresponding to a plurality of user equipments, the allocation method being capable of supporting transmission of the plurality of demodulation reference signals on the same time domain resource, and the parameter being capable of making the demodulation reference signals sent with the same time frequency resource distinguished from each other; and transmitting information indicating the allocation method and information indicating the parameter to the plurality of user equipments.