Orthogonal STF Frame Structure for Long-Distance mmW Transmission
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Solution Overview
Problem
Millimeter Wave (mmW) signals experience high packet loss rates when transmitted over long distances due to attenuation, limiting their range to approximately ten meters, making them unsuitable for extended wireless communications.
Innovation Solution
The proposed frame structure includes multiple short training fields (STFs) and field groups, with each STF being orthogonal to a legacy STF, and control fields being communicated over non-overlapping time periods, allowing for improved automatic gain control and channel estimation, thereby increasing the range of wireless signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If mmW signals are transmitted over long distances, then coverage range is extended, but packet loss rate increases due to attenuation
Solution Approach 1:
The frame structure is segmented into multiple field groups, each containing control fields that are orthogonal to each other. This segmentation allows the receiver to process multiple independent copies of control information, improving the likelihood of successful decoding over long distances where signal attenuation occurs.
Solution Approach 2:
Control fields are duplicated across multiple field groups in the frame structure. Each control field contains redundant information that can be used for channel estimation and automatic gain control. This copying strategy ensures that even if some copies are lost due to attenuation, other copies remain available for successful signal recovery.
2Measurement precision
If multiple control fields are transmitted over non-overlapping time periods, then channel estimation accuracy is improved, but transmission time increases
Solution Approach 1:
Control fields are transmitted periodically at non-overlapping time intervals within the frame structure. This periodic transmission allows the receiver to perform channel estimation at multiple discrete time points, improving accuracy while maintaining a structured timing pattern that minimizes overall transmission time.
Solution Approach 2:
Channel estimation and automatic gain control are performed using control fields transmitted before the main data payload. This preliminary action allows the receiver to prepare accurate estimation parameters in advance, improving subsequent data reception efficiency and reducing total transmission time.
3Measurement precision
If orthogonal STFs are used instead of legacy STF, then automatic gain control is improved, but frame structure complexity increases
Solution Approach 1:
The STF parameters are changed to use orthogonal sequences instead of legacy non-orthogonal sequences. This parameter change enables the receiver to distinguish between multiple STF instances through orthogonality properties, improving automatic gain control accuracy without requiring complex additional hardware, as orthogonality can be achieved through signal processing.
Data Source
AI summary
A method is described for providing extended wireless coverage. The method includes transmitting, by a station (STA), at least a first frame including one or more short training fields (STFs) and a legacy STF, each of the one or more STFs carrying a sequence of symbols that is orthogonal to a sequence of symbols carried by the legacy STF.