OFDMA Interleaver Layout for Variable Usable Tones
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Solution Overview
Problem
In orthogonal frequency division multiple access (OFDMA) for high-efficiency Wi-Fi, the dynamic variation in usable tones due to bandwidth allocation, link direction, and tone allocation positions poses challenges for efficient data transmission, affecting processing such as interleaving and link adaptation.
Innovation Solution
A dynamically generated block interleaver is selected based on the number of usable tones, allowing for flexible resource allocation and accommodating variance in usable tones by skipping unfilled entries, while maintaining backwards compatibility with existing protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed interleaver structure is used, then device complexity is reduced, but adaptability to varying usable tones deteriorates
Solution Approach 1:
The interleaver structure dynamically adjusts its parameters (number of rows, columns, and unfilled entries) based on the actual number of usable tones determined from resource allocation, link direction, and bandwidth conditions. This allows the same interleaver design to adapt to varying transmission conditions without requiring multiple fixed interleaver structures.
Solution Approach 2:
The interleaver changes its structural parameters (dimensions and filling pattern) according to the determined number of usable tones. By modifying these parameters based on transmission conditions, the interleaver maintains optimal performance across different bandwidth allocations and link directions while using a single flexible structure.
2Manufacturing precision
If overhead tones are excluded before interleaving, then manufacturing precision of resource allocation is improved, but loss of time in processing increases
Solution Approach 1:
The system performs preliminary determination of the number of usable tones by subtracting overhead tones (pilot tones, guard band tones, DC tones) from the total allocated tones before the interleaving process. This preliminary calculation enables the interleaver to be configured with the correct dimensions and filling pattern in advance, avoiding reconfiguration during transmission.
Solution Approach 2:
The interleaver structure automatically determines its own configuration parameters based on the calculated number of usable tones. The system self-adjusts the number of rows, columns, and unfilled entries without requiring external intervention or complex control logic, streamlining the processing flow.
3Object-affected harmful factors
If band guard tones are used at band edge allocation, then harmful out-of-band emission is reduced, but quantity of usable tones decreases
Solution Approach 1:
The system applies different tone allocation strategies for different frequency positions: band edge allocations use guard tones to reduce out-of-band emission, while band center allocations can use more tones for data transmission. The interleaver adapts its structure based on the local characteristics of the allocated bandwidth position, optimizing both emission control and data capacity.
Data Source
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AI summary
Certain embodiments herein relate to an interleaver based on usable tones of a resource allocation. The interleaver is selected according to the number of usable tones and may be selected for each resource allocation to accommodate the variance in usable tones. The selected codebit interleaver or symbol interleaver may be a block interleaver in which bits are sequentially read in row by row and read out column by column, such that any unfilled entries in the block interleaver are skipped.