Interleaver Design Optimizing Spatial Stream Distance
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Solution Overview
Problem
Current methods for interleaving data in wireless networks, such as those using the IEEE 802.11n and 802.11ac standards, do not efficiently distribute information bits to prevent errors caused by channel conditions, leading to suboptimal performance in terms of packet error rate (PER).
Innovation Solution
The implementation of a method that uses a PHY processing unit with multiple interleavers to perform bit permutations and frequency rotations, ensuring that adjacent coded bits are mapped onto non-adjacent locations in the frequency or time domain, thereby optimizing the interleaver parameters based on the number of data subcarriers and spatial streams to maximize the average distance between spatial streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interleaving methods are used in wireless networks, then the system maintains basic data transmission capability, but the packet error rate increases due to inefficient distribution of coded bits
Solution Approach 1:
The patent applies parameter changes by optimizing interleaver parameters including the number of interleavers, block size, and permutation patterns. These parameter adjustments transform the conventional interleaving approach into an optimized system that achieves both low packet error rates and high data transmission efficiency by adapting the interleaving configuration to specific channel conditions and data requirements
Solution Approach 2:
The patent implements segmentation by dividing the data stream into multiple blocks and distributing them across multiple interleavers. This segmentation allows coded bits to be spread across different spatial and temporal locations, preventing concentrated errors and improving overall transmission reliability while maintaining efficient throughput through parallel processing
2Ease of manufacture
If coded bits are mapped to adjacent locations in frequency or time domain, then the implementation is simple, but channel conditions cause errors in consecutive bits
Solution Approach 1:
The patent applies dimensionality change by extending the interleaving from a single-dimensional approach to a multi-dimensional structure that combines spatial distribution across multiple interleavers with temporal distribution across blocks. This transforms the simple adjacent mapping into a complex multi-dimensional pattern that maintains implementation feasibility while dramatically improving error resistance through diverse bit distribution
3Reliability
If the average distance between spatial streams is maximized, then channel performance is enhanced, but the interleaver parameter selection becomes more complex
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing optimal interleaver parameter configurations for various channel conditions and data types. This preliminary preparation allows the system to quickly select appropriate parameters without performing complex real-time optimization, thereby achieving maximum average distance between spatial streams while keeping the operational complexity manageable through lookup tables and predefined configurations
Data Source
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AI summary
In a method for interleaving information bits in a physical layer (PHY) data unit, a channel bandwidth to be used for transmitting the PHY data unit is determined and a frequency rotation parameter NROT corresponding to the channel bandwidth is selected. A spatial stream constant is selected for each spatial stream from the set [0, 5, 2, 7, 3, 6, 1, 4] or a subset thereof depending on a number of spatial streams to be utilized, wherein each constant in the set corresponds to a respective spatial stream. Information bits are interleaved according to the selected frequency rotation parameter NROT and the selected spatial stream constant.