WLAN Transform Sequence PAPR Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current WLAN systems face challenges in transmitting data at high throughput rates while maintaining compatibility with legacy systems, as higher channel bandwidths increase Peak to Average Power Ratio (PAPR), leading to increased implementation costs and potential interference with legacy stations.
Innovation Solution
The method involves generating transformed transmission information fields by multiplying the transmission information field with a transform sequence and transmitting these across multiple frequency blocks, using specific transform values and Cyclic Shift Delay (CSD) values to reduce PAPR and ensure compatibility with legacy systems, allowing for efficient data transmission in WLAN systems with channel bandwidths of 80 MHz or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If channel bandwidth is increased to support higher throughput rates, then data transmission speed is improved, but Peak to Average Power Ratio (PAPR) increases leading to higher implementation costs
Solution Approach 1:
The transmission frequency band is divided into multiple frequency blocks (e.g., 80 MHz divided into four 20 MHz blocks). The transmission information field is segmented and multiplied by different transform values in each frequency block, which reduces the PAPR of the overall transmission signal while maintaining high throughput capability.
Solution Approach 2:
Transform values (such as cyclic shift delay values) are applied to different frequency blocks to change the signal parameters. This transforms the transmission signal in a way that reduces PAPR while preserving the data transmission capability across the full bandwidth.
2Productivity
If channel bandwidth is increased to support higher throughput rates, then data transmission speed is improved, but interference with legacy stations increases
Solution Approach 1:
The wide frequency band is segmented into multiple blocks, and legacy stations can receive and process the transmission information field in their supported bandwidth (e.g., 20 MHz) without being affected by the full 80 MHz signal, thus reducing interference while maintaining high throughput for VHT stations.
Solution Approach 2:
Different parts of the frequency spectrum are assigned different transform values, allowing VHT stations to utilize the full bandwidth while legacy stations can operate in their supported bandwidth segments without experiencing excessive interference from the wider signal.
3Device complexity
If transform sequence is applied to reduce PAPR, then implementation cost is reduced, but transmission efficiency may be affected
Solution Approach 1:
Transform values are carefully selected and applied to frequency blocks in a way that reduces PAPR (lowering implementation cost) while preserving the information content and transmission efficiency. The transform operation is reversible and does not lose data.
Data Source
AI summary
A method of transmitting data in a WLAN system using a transmission frequency band including a plurality of frequency blocks includes generating a transmission information field, including at least one of information for timing acquisition of a frame, channel estimation information, and information for demodulation and decoding of the data, generating a plurality of transformed transmission information fields by multiplying the transmission information field by a transform sequence, and transmitting the plurality of transformed transmission information fields through the plurality of respective frequency blocks. The transform sequence comprises a plurality of transform values, and the plurality of transformed transmission information fields is generated by multiplying transmission information field by each of a plurality of transform values.