UE-Specific DMRS Sequence Setup for Low-Overhead Initial Communication
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Solution Overview
Problem
Current DMRS transmission modes are not fully UE-specific, leading to high overhead in RRC signaling and lack of DMRS availability during the initial phase of communication connections, as they rely on cell-specific scrambling sequences.
Innovation Solution
An apparatus and method that generate UE-specific DMRS sequences using predefined scrambling sequences with configurable calculation parameters, allowing for default values to be used initially before receiving configuration information, thereby reducing overhead and enabling DMRS-based communication from the outset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cell-specific DMRS sequences are used, then DMRS-based communication can be established, but the overhead in RRC signaling increases and the system cannot support fully UE-specific communication
Solution Approach 1:
The patent changes the parameters used for DMRS sequence generation from cell-specific identifiers to UE-specific identifiers. Specifically, it uses the RNTI (Radio Network Temporary Identifier) and scrambling IDs to generate DMRS sequences, replacing the traditional PCI (Physical Cell Identifier) based generation method. This parameter change enables fully UE-specific DMRS sequences while reducing RRC signaling overhead.
Solution Approach 2:
The patent extracts the UE-specific identification elements (RNTI, scrambling ID) from the cell-specific DMRS generation process. By separating the UE-specific parameters from the cell-specific parameters, the system can generate DMRS sequences that are specific to each UE without requiring extensive RRC signaling for configuration.
2Adaptability or versatility
If UE-specific DMRS sequences with configurable parameters are implemented, then adaptability improves, but the initial phase of communication cannot utilize DMRS-based transmission before configuration is received
Solution Approach 1:
The patent applies preliminary action by pre-configuring default values for DMRS sequence parameters (such as default scrambling IDs and RNTI values) that can be used immediately in the initial communication phase. These default parameters are established beforehand, allowing DMRS-based transmission to commence before detailed configuration is received, thus eliminating the time loss in the initial phase.
3Adaptability or versatility
If DMRS sequence generation is decoupled from cell-specific DMRS, then UE-specific communication is enabled, but complexity of the sequence generation procedure increases
Solution Approach 1:
The patent applies universality by using the same RNTI value that is already universally used for other communication purposes (such as PDCCH scrambling) also for DMRS sequence generation. This multi-functional use of RNTI simplifies the overall system complexity despite enabling UE-specific DMRS sequences, as it reuses existing identification mechanisms rather than introducing entirely new ones.
Data Source
AI summary
There is provided a mechanism for conducting a communication between at least one communication network control element such as an eNB and at least one communication element such as a UE wherein a DM RS based communication mode is used. DMRS (scrambling) sequences are generated wherein each DMRS sequence includes a set of calculation parameters being specific for the respective DMRS sequence, wherein the set of calculation parameters is configurable by the eNB during communication. For initializing each of the at least one scrambling sequence before receiving the configuration information, i.e. in an initial phase of the communication, a predetermined default value based on e.g. an UE_ID and being selectable from a set of predetermined default values is used for the set of calculation parameters in each DMRS sequence.