Buffer Descriptor Bitmaps for Packet Aggregation Search Overhead
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Solution Overview
Problem
Conventional IEEE 802.11-based LMAC systems lack a Buffer Descriptor (BD) structure for frame aggregation, leading to increased search overhead during packet aggregation, as they must search the entire BD list for aggregation conditions like Traffic IDentifier (TID), Access Category (AC), or destination, and require new BDs for each AC, resulting in inefficient resource utilization and higher transmission times.
Innovation Solution
A packet aggregation apparatus and method using bitmaps to represent the positions of Frame Descriptors (FDs) within Access Category (AC) descriptors, allowing flexible access and aggregation of packet data without grouping by ACs, reducing search overhead and enabling efficient construction of aggregated Physical Service Data Units (PSDUs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conventional IEEE 802.11-based LMAC searches the entire BD list for packet aggregation, then it can find packets meeting aggregation conditions, but the search overhead and time delay increase significantly
Solution Approach 1:
The BD list is segmented into multiple AC-specific BD lists (AC0-BD list, AC1-BD list, AC2-BD list, AC3-BD list), each managing buffers for a specific Access Category. This segmentation allows the aggregation search to be confined to relevant AC lists rather than searching the entire BD list, reducing search overhead while maintaining aggregation accuracy.
Solution Approach 2:
AC descriptors are introduced as intermediary structures that manage and organize FDs within each AC's BD list. Each AC descriptor contains a bitmap indicating which FDs belong to that AC, serving as an intermediary index that speeds up the location of packets meeting aggregation conditions without requiring a full BD list search.
2Adaptability or versatility
If new BDs are created for each AC to support packet aggregation, then packet aggregation can be implemented, but the device complexity and resource utilization increase
Solution Approach 1:
The BD structure is designed to serve multiple functions: it manages individual packet buffers, supports AC-specific organization through AC descriptors, and enables packet aggregation by allowing searches across AC boundaries. The same BD list structure is used for both individual packet management and aggregated packet management, eliminating the need for separate BD structures for different purposes.
Solution Approach 2:
The invention merges the AC-specific buffer management with the overall BD list structure by having AC descriptors point to FDs within the shared BD list. This combining approach allows multiple ACs to share the same BD list resources while maintaining AC-specific organization, reducing the need for duplicate BD structures.
3Reliability
If the BD list is organized on an AC-by-AC basis with separate data buffers for each AC, then QoS prioritization can be implemented, but the search overhead for aggregation increases
Solution Approach 1:
AC descriptors are pre-configured with bitmaps that indicate which FDs belong to each AC before aggregation is needed. This preliminary organization of FDs by AC, with pre-computed bitmaps, allows the aggregation process to quickly identify relevant packets by checking the pre-prepared AC descriptor bitmaps rather than searching through all FDs during aggregation.
Data Source
AI summary
A buffering apparatus and method for packet aggregation are provided. A buffer buffers packet data to be transmitted on a frame basis. An aggregator represents the positions of the buffered packet data in an Access Category (AC) bitmap and a Traffic Identifier (TID) bitmap according to an AC and a TID of the buffered packet data, and provides a bitmap indicating the positions of packet data to be aggregated according to an aggregation condition to an aggregation controller. The aggregation controller aggregates the packet data based on the bitmap received from the aggregator, constructs an aggregation Physical Service Data Unit (PSDU) with the aggregated packet data, and transmits the aggregation PSDU to a destination.