Dedicated Resource Unit for Ultra-Low Latency Wi-Fi
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Solution Overview
Problem
Current Wi-Fi standards, such as IEEE 802.11, face challenges in providing ultra-low latency and high reliability for time-sensitive applications like industrial automation and AR/VR, due to high overhead in data exchange and non-deterministic medium access control, which is inadequate for isochronous transmission of small packets with stringent latency requirements.
Innovation Solution
Implementing a dedicated resource unit (RU) for time-critical ultra-low latency (ULL) data transmission within uplink multi-user orthogonal frequency division multiple access (MU OFDMA) data transmission, allowing ULL data to start at any time during the UL PPDU and using medium access control layer padding until ULL data is available, along with a time-synchronized scheduled access mechanism to reduce latency and increase reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If triggered-based OFDMA operation is used in IEEE 802.11ax, then multi-user data transmission capability is improved, but overhead increases especially for small packet sizes
Solution Approach 1:
The patent segments the OFDMA transmission by designating specific resource units (RUs) exclusively for time-sensitive small packets. This segmentation allows small packets to have dedicated transmission resources separate from general data traffic, reducing the overhead impact on time-critical communications while maintaining multi-user capability.
Solution Approach 2:
The patent applies local quality by providing differentiated service qualities to different packet types within the same OFDMA transmission. Time-sensitive small packets receive prioritized handling in designated RUs with reduced overhead, while other traffic follows standard procedures, thus optimizing performance for critical applications without compromising overall system productivity.
2Reliability
If standard Wi-Fi protocols with retransmissions are used, then reliability can be improved through error correction, but latency increases due to multiple retransmission cycles
Solution Approach 1:
The patent extracts time-sensitive small packets from the standard Wi-Fi retransmission protocol cycle by directing them through a specialized transmission path using designated RUs. This extraction allows critical packets to bypass the multi-cycle retransmission process that characterizes standard Wi-Fi, achieving both high reliability and ultra-low latency by eliminating unnecessary retransmission delays for time-critical traffic.
Solution Approach 2:
The patent implements preliminary action by pre-allocating specific resource units for time-sensitive traffic and establishing dedicated transmission paths before data arrival. This preliminary configuration enables immediate transmission of small packets without waiting for standard protocol handshakes or retransmission cycles, thus maintaining reliability while minimizing latency.
3Reliability
If isochronous transmission with cyclic packets is implemented, then time-sensitive application requirements are met, but medium access control overhead increases
Solution Approach 1:
The patent segments the medium access control by creating a specialized transmission mechanism for isochronous packets within the OFDMA framework. Designated RUs provide dedicated access paths that eliminate standard MAC overhead for time-sensitive traffic, allowing cyclic packets to be transmitted with guaranteed timing while reducing the burden on overall medium access control.
Solution Approach 2:
The patent changes key transmission parameters for packets in designated RUs, including reduced preamble lengths, simplified acknowledgment mechanisms, and optimized resource allocation. These parameter changes significantly reduce medium access control overhead for isochronous transmission while maintaining the required time-sensitivity guarantees for industrial automation and similar applications.
Data Source
AI summary
Embodiments disclosed herein are directed to communicating time-critical ultra-low latency (ULL) data using one or more dedicated resource units (RUs). A station (STA) decodes a trigger frame received from an access point station (AP) encoded to indicate resource units (RUs) of an UL PPDU for an uplink multi-user orthogonal frequency division multiple access (UL MU OFDMA) data transmission by a first and a second station STA. The trigger frame may also be encoded to indicate configuration information for a dedicated RU for time-critical ultra-low latency (ULL) UL data. The dedicated RU may be one RU of one or more RUs of the UL PPDU that are reserved for time-critical communications. The STA may encode time-critical ULL UL data for transmission to the AP on the dedicated RU during the uplink MU OFDMA data transmission by the first and second STAs. The time-critical ULL UL data may start at any time during transmission of the UL PPDU. Medium access control layer (MAC) padding may be included in a MAC payload until the time-critical ULL UL data is available at the MAC layer of the STA.