Dynamic Cyclic Prefix Length Adjustment in WLANs
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Solution Overview
Problem
High-density environments in Wireless Local Area Networks (WLANs) lead to inefficiencies due to the inability of existing technologies to effectively manage cyclic prefix lengths, resulting in reduced communication efficiency and increased overhead, especially when using OFDMA and UL MU-MIMO techniques.
Innovation Solution
The system and method for setting cyclic prefix length dynamically adjust the prefix length based on scheduling information, using explicit or implicit indicators, allowing for efficient communication without the need for timing advance commands, thereby reducing overhead and maintaining signal orthogonality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed long cyclic prefix is used to accommodate propagation delays in high-density WLANs, then signal orthogonality is maintained, but communication overhead increases
Solution Approach 1:
The patent applies dynamics by making the cyclic prefix length adjustable rather than fixed. The system dynamically selects between first and second cyclic prefix lengths based on propagation delay conditions, allowing the cyclic prefix to adapt to different channel conditions while maintaining signal orthogonality when needed and reducing overhead when propagation delays are minimal
Solution Approach 2:
The patent changes the parameter of cyclic prefix length based on propagation delay characteristics. By monitoring or estimating propagation delay and selecting appropriate cyclic prefix lengths (first length for larger delays, second length for smaller delays), the system optimizes the balance between maintaining orthogonality and reducing overhead
2Productivity
If timing advance commands are used to adjust cyclic prefix length, then communication efficiency improves, but signaling overhead increases
Solution Approach 1:
The patent applies self-service by enabling stations to autonomously determine the appropriate cyclic prefix length based on scheduling information received from the access point. The scheduling information contains indicators that allow stations to self-select between different cyclic prefix lengths without requiring explicit timing advance commands, thereby reducing signaling overhead while maintaining communication efficiency
Solution Approach 2:
The access point performs preliminary action by including cyclic prefix length indicators in the scheduling information before the actual data transmission. This allows stations to pre-configure the appropriate cyclic prefix length based on the indicators, eliminating the need for subsequent timing advance command exchanges and reducing overall signaling overhead
Data Source
AI summary
A method for communicating in a wireless communications system includes receiving scheduling information including information for an uplink transmission scheduled for the station, and determining a first length of a first cyclic prefix for a transmission in accordance with the scheduling information. The method also includes transmitting the transmission with the first cyclic prefix.