Variable BlockACK Bitmap for Wireless Network Bandwidth Efficiency
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Solution Overview
Problem
Current block acknowledgement mechanisms in IEEE 802.11 wireless networks are inefficient, particularly due to a fixed-length BlockACK bitmap and limitations in acknowledging data packets across multiple traffic classes and streams, leading to bandwidth waste and throughput degradation.
Innovation Solution
A method that uses a variable-sized BlockACK bitmap to selectively acknowledge successfully or incorrectly received data packets, allowing for flexible acknowledgement across multiple traffic classes and streams, and reduces the number of sequence control fields by using adaptive positive or negative ACKs, thereby optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-length BlockACK bitmap is used to acknowledge data packets, then all packets can be acknowledged, but bandwidth is wasted when most packets are received successfully
Solution Approach 1:
The patent applies dynamics by changing the BlockACK bitmap from a fixed length to a variable length that adapts to the actual number of unsuccessfully received packets. The bitmap length is dynamically adjusted based on the count of NACKed packets, allowing the acknowledgment mechanism to be flexible and efficient rather than rigid and wasteful.
Solution Approach 2:
The patent changes the parameter of bitmap length from a fixed value to a variable value that depends on the number of failed packet receptions. This parameter change enables the system to reduce overhead when most packets are successful, while still maintaining complete acknowledgement capability when needed.
2Adaptability or versatility
If a fixed-length BlockACK bitmap is used, then all traffic classes can be acknowledged, but throughput degrades due to excessive overhead
Solution Approach 1:
The patent makes the BlockACK bitmap length dynamic based on the actual number of packets that need acknowledgement across multiple traffic classes. This allows the system to maintain support for various traffic classes while reducing overhead when fewer packets require acknowledgement, thereby improving throughput.
Solution Approach 2:
The patent changes the bitmap length parameter adaptively based on the number of unsuccessfully received packets across different traffic classes. This parameter adjustment allows the system to maintain versatility in handling multiple traffic classes while optimizing throughput by reducing unnecessary overhead.
3Reliability
If per-packet ACK messages are sent, then complete acknowledgement is achieved, but channel efficiency decreases due to frequent transmissions
Solution Approach 1:
The patent merges multiple per-packet ACK messages into a single BlockACK message that can acknowledge multiple packets at once. By combining acknowledgements for multiple packets into one transmission, the system maintains complete acknowledgement while significantly improving channel efficiency and reducing the frequency of transmissions.
Solution Approach 2:
The patent makes the BlockACK mechanism dynamic by adjusting the bitmap length based on the number of packets that actually need acknowledgement. This allows the system to achieve complete acknowledgement for all packets while optimizing channel efficiency by only transmitting the necessary number of acknowledgment bits rather than always transmitting a fixed maximum.
Data Source
AI summary
A method selectively acknowledges data packets in a network including a multiple stations connected by a common wireless channel. A transmitting station requests a block acknowledgement from a receiving station. The transmitting station transmits a block of data packets to the receiving station. The receiving station determines a number of successfully received data packets and a number of incorrectly received packets. Then, the receiving station selectively acknowledges only the successfully received data packets if the number of usefully received data packets is less than the number of incorrectly received data packets, and otherwise acknowledging only the incorrectly received packets.