Variable-Length Acknowledgement Fields in WLAN A-MPDU Transmissions
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Solution Overview
Problem
Current wireless local area networks (WLANs) face challenges in efficiently acknowledging data units, particularly in multi-user scenarios with orthogonal frequency division multiple access (OFDMA) transmissions, where existing methods lack flexibility in acknowledging multiple media access control (MAC) protocol data units (MPDUs) and do not effectively manage buffer sizes for acknowledgment data units.
Innovation Solution
The method involves generating acknowledgment data units with variable-length acknowledgement fields, selected from a subset of predetermined lengths based on negotiated buffer sizes, to acknowledge multiple MAC protocol data units, and transmitting these units in wireless local area networks, supporting OFDMA and multi-user multiple input multiple output (MU-MIMO) transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-length acknowledgement fields are used, then device complexity is reduced, but acknowledgment efficiency and adaptability to buffer sizes deteriorate
Solution Approach 1:
The patent implements variable-length acknowledgement fields that dynamically adapt to the actual number of MPDUs being acknowledged and the negotiated buffer size. The acknowledgement field length is selected from a set of predetermined lengths based on the negotiated buffer size, allowing the system to optimize between fixed simplicity and variable efficiency depending on the specific transmission scenario.
Solution Approach 2:
The patent changes the parameter of acknowledgement field length from a fixed value to a variable value selected from multiple predetermined lengths. This parameter change allows the acknowledgement field to scale with the buffer size negotiated between devices, improving acknowledgment efficiency without requiring completely flexible variable-length structures that would increase complexity.
2Productivity
If variable-length acknowledgement fields are used, then acknowledgment efficiency improves, but device complexity increases
Solution Approach 1:
The patent implements variable-length acknowledgement fields that dynamically adapt to the actual number of MPDUs being acknowledged and the negotiated buffer size. The acknowledgement field length is selected from a set of predetermined lengths based on the negotiated buffer size, allowing the system to optimize between fixed simplicity and variable efficiency depending on the specific transmission scenario.
Solution Approach 2:
The patent changes the parameter of acknowledgement field length from a fixed value to a variable value selected from multiple predetermined lengths. This parameter change allows the acknowledgement field to scale with the buffer size negotiated between devices, improving acknowledgment efficiency without requiring completely flexible variable-length structures that would increase complexity.
3Device complexity
If buffer size is not negotiated, then setup procedure complexity is reduced, but adaptability to different transmission scenarios deteriorates
Solution Approach 1:
The patent performs buffer size negotiation as a preliminary action during the acknowledgement setup procedure, before actual data transmission begins. This preliminary negotiation establishes the maximum buffer size that both devices can handle, allowing subsequent acknowledgements to be optimized for this known capacity without requiring complex runtime adjustments or larger default buffers.
Solution Approach 2:
The patent uses the negotiated buffer size as a parameter to determine the appropriate acknowledgement field length from a set of predetermined lengths. This parameter-based approach allows the system to adapt to different transmission scenarios while maintaining a manageable setup procedure complexity through structured negotiation.
4Reliability
If maximum buffer size is allocated for all acknowledgements, then acknowledgment reliability is improved, but resource utilization efficiency deteriorates
Solution Approach 1:
The patent changes the acknowledgement field length parameter based on the negotiated buffer size, selecting from multiple predetermined lengths. This allows the system to allocate exactly the right amount of acknowledgement space for each transmission scenario, ensuring reliability by having sufficient buffer capacity while avoiding waste by not over-allocating resources for smaller transmissions.
Solution Approach 2:
The patent implements dynamic adaptation of acknowledgement field length to match the actual buffer size negotiated for each device pair. This dynamic approach ensures that acknowledgements are reliable by having adequate buffer capacity when needed, while improving resource utilization efficiency by using smaller acknowledgement fields when the negotiated buffer size is smaller.
Data Source
AI summary
A first communication device receives an aggregate medium access control data unit (MAC) protocol data unit (A-MPDU) that aggregates multiple MAC protocol data units from a second communication device. The first communication device generates an acknowledgment data unit that includes a length indication that indicates a length of an acknowledgement field and the acknowledgment field of the indicated length. The length of the acknowledgement field is selected from a subset of predetermined lengths, among a set predetermined lengths, that includes multiple predetermined lengths that do not exceed a maximum number of MAC protocol data units that can be included in the A-MPDU. The maximum number of MAC protocol data units is limited by a buffer size negotiated in an acknowledgement setup procedure previously conducted between the first communication device and the second communication device. The first communication device transmits the acknowledgment data unit to the second communication device.