Group-Based Resource Element Mapping for LTE Data Transmission
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Solution Overview
Problem
In LTE radio technology, the mapping of code blocks to resource elements in a time-frequency grid leads to inefficiencies due to localized channel conditions, broadband interference, and imbalance in decoding performance, particularly when using multiple MIMO layers or high-order modulation schemes, which can result in failed transmissions and complications in channel estimation and MIMO equalization.
Innovation Solution
The method involves dividing the allocated bandwidth into groups of resource elements, each covering multiple consecutive elements in the time domain and distinct in the frequency domain, allowing data symbols to be mapped consecutively across these groups to spread them evenly, thereby reducing the impact of localized interference and improving frequency diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If code blocks are mapped to localized resource elements in the frequency domain, then mapping simplicity is improved, but transmission reliability deteriorates due to localized channel conditions and broadband interference
Solution Approach 1:
The patent segments the frequency domain resources into multiple PRB bundles and further divides code blocks into segments that are mapped to different PRB bundles. This segmentation ensures that code blocks are distributed across frequency-diverse resources, reducing the impact of localized interference and improving transmission reliability while maintaining manageable mapping complexity through structured organization.
Solution Approach 2:
The patent introduces time-domain diversity by mapping code block segments to different PRB bundles across multiple time slots. This dimensional expansion from purely frequency-domain mapping to time-frequency domain mapping provides additional diversity against broadband interference and localized channel conditions, improving reliability without significantly increasing mapping complexity.
2Measurement precision
If code blocks are mapped to contiguous frequency resources, then decoding performance is improved through frequency localization, but susceptibility to broadband interference increases
Solution Approach 1:
The patent segments each code block into multiple segments and maps them to non-contiguous PRB bundles distributed across the frequency spectrum. This segmentation maintains decoding performance by keeping segments within manageable size while reducing broadband interference susceptibility through frequency diversity, as interference affecting one PRB bundle does not necessarily affect others.
Solution Approach 2:
The patent applies local quality mapping where different segments of the same code block are mapped to PRB bundles with different frequency characteristics. This allows the system to exploit local frequency diversity, where each segment experiences different channel conditions and interference patterns, improving overall decoding robustness against broadband interference.
3Measurement precision
If resource elements are grouped into PRB bundles for channel estimation, then channel estimation accuracy is improved, but complexity of handling multiple bundles increases
Solution Approach 1:
The patent segments the frequency domain into PRB bundles and maps code block segments to different bundles, allowing channel estimation to be performed independently for each bundle. This segmentation improves channel estimation accuracy by focusing on localized frequency regions while managing complexity through independent processing of each bundle, avoiding the need to handle all bundles simultaneously.
Solution Approach 2:
The patent performs channel estimation for each PRB bundle beforehand before decoding the code blocks. This preliminary action prepares the channel state information in advance, improving estimation accuracy while reducing real-time complexity by separating the estimation and decoding operations into distinct phases.
4Reliability
If data symbols are mapped consecutively across PRB bundles, then frequency diversity is improved, but mapping complexity increases
Solution Approach 1:
The patent segments code blocks into multiple segments and maps each segment to different PRB bundles in a systematic consecutive manner. This segmentation achieves frequency diversity by distributing code block energy across multiple frequency regions while managing mapping complexity through a structured, repeatable mapping pattern that can be efficiently implemented.
Solution Approach 2:
The patent extends the mapping from two-dimensional frequency resources to three-dimensional time-frequency resources by mapping code block segments across multiple PRB bundles in different time slots. This dimensional expansion provides frequency diversity while managing complexity through the structured alternation between frequency and time dimensions.
Data Source
AI summary
For transmitting data over a radio interface using subframes with a plurality of resource elements organized in a time-frequency grid, at least two groups of resource elements are determined from the resource elements of one of the subframes. Each group covers multiple consecutive resource elements in the time domain and is distinct from the at least one other group in the frequency domain. Data symbols of a sequence are consecutively mapped to the resource elements of one of the groups. If a data symbol is mapped to each resource element of the group, the next data symbols of the sequence are consecutively mapped to the resource elements of a further one of the groups.