Wireless LAN Pilot Signal Timing for Delayed Block ACK Feedback
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Solution Overview
Problem
In communication systems employing the delayed block ACK scheme, the long interval between data transmission and block ACK feedback reduces the accuracy and usefulness of reception quality information, hindering appropriate data transmission control through adaptive modulation and bit loading.
Innovation Solution
A communication system configuration that includes a wireless LAN base station with a pilot transmission section and a station equipped with a reception quality measurement section, which generates and adds reception quality information to the block ACK, enabling timely and accurate feedback for data transmission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a delayed block ACK scheme is used to temporarily open the media when priority of data transmission is not particularly high or when the media is extremely congested, then flexibility in media access is improved, but the time interval between data transmission and block ACK feedback increases, reducing the accuracy and usefulness of reception quality information
Solution Approach 1:
The patent applies preliminary action by transmitting the pilot signal before the block ACK feedback is returned. This allows the receiving station to measure reception quality in advance using the pilot signal, ensuring that the reception quality information remains accurate and fresh even when there is a long interval between data transmission and block ACK feedback. The pilot signal is transmitted at a timing earlier than the block ACK, enabling proactive quality measurement.
2Device complexity
If the block ACK frame is used as a medium for transmitting feedback information, then the device complexity is reduced, but the time interval between data transmission and feedback returns increases, making the feedback information less useful for data transmission control
Solution Approach 1:
The patent applies preliminary action by transmitting the pilot signal before the block ACK feedback is returned. This allows the receiving station to measure reception quality in advance using the pilot signal, ensuring that the reception quality information remains accurate and fresh even when there is a long interval between data transmission and block ACK feedback. The pilot signal is transmitted at a timing earlier than the block ACK, enabling proactive quality measurement.
3Productivity
If adaptive modulation and adaptive bit loading are implemented to improve data transmission control, then productivity is improved, but reception quality information feedback becomes necessary, increasing device complexity
Solution Approach 1:
The patent applies universality by making the block ACK frame serve multiple functions: it simultaneously carries both the acknowledgment information and the reception quality feedback information. The receiving station measures reception quality from the pilot signal and embeds this information in the block ACK frame, allowing the same frame structure to fulfill both ACK and feedback transmission purposes, thereby avoiding additional dedicated feedback frames or channels.
4Productivity
If the receiving station immediately integrates ACKs into a block ACK frame as in the immediate block ACK scheme, then channel efficiency is improved, but the flexibility to temporarily open the media when congestion occurs is reduced
Solution Approach 1:
The patent applies dynamics by enabling the system to adaptively choose between immediate block ACK and delayed block ACK modes based on current channel conditions. The delayed block ACK scheme allows the receiving station to temporarily hold the media when congestion is detected or when data transmission priority is low, while still maintaining the capability to provide accurate reception quality feedback through the pilot signal mechanism.
Data Source
AI summary
A communication system which can control a data transmission properly and to which a Delayed Block ACK mode is applied, and a communication device constituting the communication system. A radio LAN base station (100) as the communication device comprises a transmission control unit (115) for transmitting a block ACK request, a pilot generation unit (104) for generating a pilot signal to measure a reception quality, and the transmission control unit (115) for transmitting the pilot signal before the block ACK having the reception quality information of the pilot signal added thereto is returned from a reception side in response to the block ACK request. A station (200) as the communication device comprises a transmission control unit (207) for controlling the transmission timing of the block ACK answering the block ACK request, a reception quality information generation unit (211) for generating the reception quality information of the pilot signal, and a block ACK generation unit (208) for adding the reception quality information to the block ACK.