Fragmented Frame Acknowledgement via NDP BlockACK Segmentation
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Solution Overview
Problem
Current IEEE 802.11 systems face inefficiencies in acknowledging fragmented frames due to high overhead in normal ACK policies and limitations in BlockACK policies, particularly in IEEE 802.11ah systems where only eight fragmented frames can be acknowledged in a single NDP BlockACK, leading to increased communication latency and power consumption.
Innovation Solution
Implementing an efficient acknowledgement procedure that uses NDP BlockACK frames for fragments greater than X, allowing up to L*X frames to be acknowledged, by incorporating a Fragment Number subfield in the Sequence Control field and determining the ACK policy based on the fragment index, enabling the use of BlockACK for some fragments and Implicit BlockACK for others to optimize acknowledgement responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal ACK policy is used for each fragmented frame, then reliable delivery acknowledgment is ensured, but communication overhead and latency increase significantly
Solution Approach 1:
The patent combines multiple individual ACK responses into a single BlockACK response that acknowledges multiple fragmented frames simultaneously. The receiver maintains a buffer to store fragmented frames and sends one consolidated BlockACK containing bitmap information indicating which frames were successfully received, thereby reducing communication overhead and latency while maintaining reliable delivery acknowledgment.
2Productivity
If BlockACK policy is used to reduce overhead, then acknowledgment efficiency improves, but the capacity to acknowledge fragmented frames is limited to eight frames per NDP BlockACK
Solution Approach 1:
The patent segments the acknowledgment process into multiple NDP BlockACK transmissions. When the number of fragmented frames exceeds eight, the receiver divides the bitmap into multiple segments and sends separate NDP BlockACKs for each segment. Each NDP BlockACK contains an A-Start parameter indicating the starting frame number of the bitmap segment, allowing the transmitter to reconstruct the complete acknowledgment status across multiple transmissions.
3Reliability
If fragmented frames are transmitted with sequential ACK waiting, then each frame delivery is confirmed, but transmission efficiency decreases due to repeated acknowledgments
Solution Approach 1:
The receiver performs preliminary action by buffering multiple fragmented frames before sending a single BlockACK response. Instead of immediately acknowledging each received fragment, the receiver waits in a buffered state to accumulate multiple frames, then sends one consolidated BlockACK that covers all buffered frames. This preliminary buffering action enables efficient batch acknowledgment while maintaining reliable delivery confirmation for each fragment.
Data Source
AI summary
Logic for communications with an efficient acknowledgement (ACK) procedure for fragmented frames. Logic may determine an acknowledgement protocol to handle more fragments of a frame than the maximum that can be included in a bitmap of an NDP (null data packet) block acknowledgement (BlockACK). Logic may determine fragment indices to associate with an implicit ACK policy. Logic may read the Fragment Number field value in the Sequence Control field of a data frame to determine the fragment index. Logic may transmit an NDP BlockACK frame for every X fragments with fragment indices greater than X−1 so that L NDP BlockACK frames can acknowledge N fragmented frames. Logic may determine a bit number in a bitmap associated with a fragment index.