Multi-Link Channel Observation with Synchronized NDP Timing
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Solution Overview
Problem
Existing wireless communication systems face challenges in securing high time correlation for channel state observation in multi-link operations, particularly when STAs with varying channel characteristics are multiplexed, leading to inefficient resource allocation and reduced spectrum efficiency.
Innovation Solution
A communication device and method that utilize synchronized transmission timing of Test signals or Null Data Packets for channel state observation across multiple links, enabling resource allocation based on high time correlation and improving spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If observation is performed on a large number of links, then channel characteristics can be obtained for all links, but time correlation cannot be secured due to difference in observation timing
Solution Approach 1:
The patent applies preliminary action by having the AP transmit NDP (Null Data Packet) signals on multiple links in advance before actual resource allocation. This allows the AP to pre-obtain channel state information for all links, ensuring that channel characteristics are measured at the same reference time point, thereby maintaining time correlation across multiple links.
Solution Approach 2:
The patent merges the channel observation process across multiple links by using a unified NDP transmission mechanism. Instead of observing each link separately at different times, the AP transmits NDP signals simultaneously or in a coordinated manner on multiple links, combining the observation into a single time-synchronized operation that preserves time correlation.
2Productivity
If STAs with good channel characteristics and STAs with poor channel characteristics are multiplexed in MU communication, then resource utilization is improved, but RSSI of the AP is rate-limited according to the STA with poor channel characteristics
Solution Approach 1:
The patent applies local quality by allocating different resource amounts to different STAs based on their individual channel characteristics. Instead of uniform resource allocation, the AP determines the amount of resource to allocate to each STA according to its specific channel quality, allowing STAs with good channel characteristics to receive more resources while STAs with poor characteristics receive appropriate resources without dragging down the entire system's RSSI performance.
Solution Approach 2:
The patent implements dynamic resource allocation where the resource allocation amount is adjusted based on observed channel characteristics. The system dynamically determines resource allocation amounts for each STA in each resource allocation period based on current channel conditions, enabling flexible adaptation to varying channel qualities while maintaining overall system efficiency.
3Loss of time
If synchronized transmission timing of Test signals or Null Data Packets is used for channel state observation, then high time correlation is secured, but coordination complexity increases
Solution Approach 1:
The patent uses the AP as an intermediary to coordinate synchronized NDP transmissions across multiple links. The AP generates and transmits NDP signals on multiple links according to a predetermined rule, acting as a central coordinator that simplifies the synchronization process. This intermediary approach avoids the need for complex peer-to-peer coordination between multiple devices while maintaining time correlation.
Data Source
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AI summary
A communication device for observing a channel state in a plurality of links is provided. A communication device that performs wireless communication using a plurality of links includes a first transmission unit that transmits a first signal including information regarding start of observation of a channel state in part of the plurality of links, and a second transmission unit that transmits a second signal inducing a signal including information regarding observation of a channel state in one or more links among the plurality of links. The first signal includes information regarding a link for performing the observation and information regarding a third signal for another communication device to observe a channel state.