Block Acknowledgement Bitmap Reuse for Memory Reduction
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Solution Overview
Problem
The existing IEEE 802.11e Standard's immediate Block ACK mechanism imposes large memory requirements on recipients due to the need for maintaining multiple BA bitmaps for each BA agreement, which increases storage demands and reduces channel efficiency.
Innovation Solution
Restricting the originator to issue a block acknowledgement request (BAR) prior to the end of a transmit opportunity (TXOP), allowing recipients to discard receive state information and reuse a single BA bitmap across different BA sessions, thereby reducing memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the immediate BA mechanism maintains multiple BA bitmaps for each BA agreement, then the throughput gains and support for high-bandwidth traffic are achieved, but the memory requirements and storage demands increase significantly
Solution Approach 1:
The patent makes the BA bitmap universal by allowing it to be reused across different BA sessions. Instead of maintaining separate BA bitmaps for each BA agreement, a single BA bitmap structure is used that can be reset and reused for new sessions, enabling the same memory resource to serve multiple functions and sessions.
Solution Approach 2:
The patent implements discarding of receive state information when it is no longer needed. The BA bitmap is cleared after serving its purpose in a BA session, and the same bitmap structure is recovered and reused for subsequent BA sessions, eliminating the need to continuously allocate memory for multiple concurrent bitmaps.
2Reliability
If the recipient maintains receive state information for each BA agreement, then the block acknowledgement functionality is provided, but the channel efficiency decreases due to increased storage demands
Solution Approach 1:
The BA bitmap is designed to be multi-functional, serving different BA sessions sequentially rather than requiring dedicated instances for each session. This universal approach maintains the reliability of block acknowledgement functionality while improving channel efficiency by reducing storage overhead.
Solution Approach 2:
Instead of maintaining multiple physical BA bitmap structures, the patent uses a single BA bitmap that is copied or reset for different sessions. The logical copy through resetting allows the same physical memory structure to represent different BA agreements at different times, reducing storage demands while preserving functionality.
3Adaptability or versatility
If multiple BA bitmaps are maintained for different BA agreements, then the selective acknowledgement capability is provided, but the device complexity increases
Solution Approach 1:
The patent employs a universal BA bitmap that can adapt to different BA agreements through resetting and reuse. This single multi-functional structure provides selective acknowledgement capability across multiple sessions without requiring complex management of multiple separate bitmap structures, thereby reducing device complexity.
Solution Approach 2:
The patent merges the functionality of multiple BA bitmaps into a single BA bitmap structure. By combining what would otherwise require separate memory allocations and management structures into one reusable bitmap, the device complexity is reduced while maintaining the ability to provide selective acknowledgement for multiple BA agreements.
Data Source
AI summary
An apparatus and method for block acknowledgements with reduced recipient state information are described. In one embodiment, the method comprises the storing of a receive state for a block of frames received during a transmission opportunity (TXOP) with an on-chip state memory. Once stored, an immediate block acknowledgement, including the receive state information, may be transmitted to an originator according to a block acknowledgement request (BAR) received during the TXOP. In the embodiments described, the BAR is received during the TXOP in which the block of data frames were transmitted to a recipient. In one embodiment, the recipient is free to discard the receive state information to free space within the on-chip system memory by requiring the originator to maintain the receive state information of blocks of data frames transmitted during TXOPs. Other embodiments are described and claimed.