DMRS Mapping for 16-Layer Wireless Systems
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Solution Overview
Problem
Current wireless communication systems, such as LTE, face challenges in efficiently transmitting and receiving reference signals for multiple layers, which limits the number of demodulable streams and increases complexity, especially when the number of layers exceeds a predetermined number.
Innovation Solution
The method involves generating a demodulation reference signal (DMRS) sequence and mapping it into resource elements across multiple antenna ports, using a pattern that reduces density in the frequency domain and alternates layer allocation between antenna port groups if the number of layers exceeds a certain threshold, allowing for efficient transmission and reception of up to 16 multiple streams while minimizing changes to existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of layers is increased beyond the predetermined number (8 layers), then the demodulation capacity and number of supported streams are improved, but the system complexity and difficulty of detecting and measuring reference signals increase significantly
Solution Approach 1:
The patent segments the reference signal detection process by introducing a mapping relationship between CDM groups and layers. When the number of layers exceeds 8, the reference signals are divided into different CDM groups (first CDM group for layers 1-8, second CDM group for layers 9-16), allowing the receiver to detect reference signals in a segmented manner rather than attempting to detect all layers simultaneously, thus reducing detection complexity.
Solution Approach 2:
The patent introduces an additional dimension of CDM group indexing to organize reference signals. By mapping layers to both CDM groups and orthogonal cover codes (OCC), the system creates a two-dimensional structure for reference signal organization, which helps the receiver systematically detect and differentiate reference signals across multiple layers without overwhelming complexity.
2Productivity
If the number of layers is increased to support more streams, then the productivity and data transmission capacity are improved, but the device complexity and structural complexity increase
Solution Approach 1:
The patent makes the existing DMRS structure universal by demonstrating that the same basic framework (CDM groups, OCC mapping, resource element allocation) can support both 8-layer and 16-layer configurations. The system reuses the established DMRS structure with extended layer mapping rules, avoiding the need for completely new reference signal designs and reducing overall system complexity.
Solution Approach 2:
The patent changes key parameters of the DMRS structure to support higher layer counts: extending the OCC length from 4 to 8, introducing second CDM groups, and modifying the layer-to-CDM-group mapping rules. These parameter changes allow the system to support 16 layers while maintaining compatibility with the existing DMRS framework, thereby increasing productivity without proportionally increasing complexity.
3Quantity of substance
If the DMRS structure is significantly changed to support 16 layers, then the demodulation capacity is improved, but the ease of manufacture and implementation difficulty increase
Solution Approach 1:
The patent copies and reuses the existing DMRS structure designed for 8 layers, extending it to support 16 layers through systematic repetition and adaptation. The same fundamental structures (CDM groups, resource element patterns, mapping procedures) are copied and applied to the extended layer range, making implementation easier by leveraging existing designs rather than creating entirely new structures.
Solution Approach 2:
The patent performs preliminary actions by establishing clear mapping rules and configurations for extended layers before actual data transmission. The layer-to-CDM-group mapping, OCC assignments, and resource element allocations are predetermined and signaled to the UE in advance, allowing the UE to prepare its detection procedures beforehand, thereby simplifying the implementation process.
Data Source
AI summary
A method for transmitting, by a base station, a demodulation reference signal (DMRS) in a wireless communication system according to one embodiment of the present invention comprises the steps of generating a DMRS sequence; mapping the DMRS sequence to resource elements of respective layers; and transmitting, through respective antenna ports corresponding to the respective layers, the DMRS sequence mapped to the resource elements, wherein if the number of layers exceeds a predetermined number, the DMRS sequence is mapped to the resource elements according to a pattern on at least two bundled consecutive resource blocks.