OFDM Channel Interleaving for Equal Code Block Allocation
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Solution Overview
Problem
Existing OFDM systems face challenges in maximizing time and frequency diversity and minimizing interference between code blocks while efficiently utilizing limited transmission resources, particularly in 3GPP LTE systems.
Innovation Solution
The method involves dividing a time and frequency resource block into equal duration resource elements, segmenting data blocks into code blocks, and using an index scheme to assign resource elements to code blocks in a way that ensures equal resource allocation and interleaving, which can be adjusted based on the number of code blocks and data block size to optimize resource utilization and diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data blocks are segmented into multiple code blocks for transmission, then the data transmission reliability is improved through diversity, but interference between different code blocks increases
Solution Approach 1:
The patent segments data blocks into multiple code blocks for parallel transmission across different subcarriers. This segmentation enables diversity transmission where each code block experiences independent fading conditions, improving reliability. The resource element assignment formulas ensure proper distribution of subcarriers to different code blocks while maintaining orthogonality and minimizing mutual interference.
Solution Approach 2:
The patent applies local quality by assigning different resource element patterns to different code blocks based on their specific characteristics and positions. Each code block receives a unique set of resource elements determined by formulas that consider the code block index, total number of code blocks, and available resource elements, thereby optimizing each code block's transmission quality while minimizing interference with others.
2Reliability
If resource elements are allocated to maximize code block diversity, then transmission reliability improves, but resource allocation complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-defining resource element assignment patterns and formulas before transmission. The resource element indices are calculated using deterministic formulas that take into account the code block index, total number of code blocks, and available resource elements. This preliminary structuring simplifies the allocation process during actual transmission while ensuring optimal diversity distribution.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting resource element assignments based on system conditions such as the number of available resource elements (N), the number of code blocks (Nseg), and the code block index (j). The assignment formulas adapt to different transmission scenarios by changing the distribution parameters, thereby maximizing diversity while maintaining manageable allocation complexity through mathematical relationships.
3Productivity
If code blocks are assigned to continuous time resource units, then resource utilization efficiency improves, but time diversity is reduced
Solution Approach 1:
The patent transitions from purely time-based continuous allocation to a two-dimensional allocation approach combining time and frequency dimensions. Resource elements are distributed across both time (OFDM symbols) and frequency (subcarriers) dimensions using formulas that consider both temporal and spectral resources. This dimensional expansion allows efficient resource utilization while maintaining time diversity through non-contiguous time resource assignment.
Solution Approach 2:
The patent segments the time resource into discrete OFDM symbols and assigns code blocks to specific symbol indices using calculated patterns rather than continuous allocation. The resource element assignment formulas distribute code blocks across different time symbols and frequency subcarriers, creating a segmented allocation pattern that improves time diversity while maintaining overall resource utilization efficiency through systematic distribution.
Data Source
AI summary
A method and apparatus for channel interleaving in a wireless communication system. In one aspect of the present invention, the data resource elements are assigned to multiple code blocks, and the numbers of data resource elements assigned to each code block are substantially equal. In another aspect of the present invention, a time-domain-multiplexing-first (TDM-first) approach and a frequency-domain-multiplexing-first (FDM-first) approach are proposed. In the TDM-first approach, at least one of a plurality of code blocks are assigned with a number of consecutive data carrying OFDM symbols. In the FDM-first approach, at least one of the plurality of code blocks are assigned with all of the data carrying OFDM symbols. Either one of the TDM first approach and the FDM-first approach may be selected in dependence upon the number of the code blocks, or the transport block size, or the data rate.