WLAN Relay Channel Estimation Using Triggered Sounding Signals
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Solution Overview
Problem
Existing wireless LAN systems face challenges in efficiently performing relay operations for extended range and reliable communication, particularly in next-generation Wi-Fi standards like IEEE 802.11be, where relay channel estimation is lacking.
Innovation Solution
A method and apparatus for relay channel estimation in a WLAN system, involving a station (STA) receiving a relay trigger frame, monitoring a signal for measuring a relay channel, obtaining channel information, and transmitting it, as well as a relay STA relaying signals based on measurement results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If relay operation is implemented to extend communication range, then coverage is improved, but channel estimation accuracy deteriorates due to lack of dedicated estimation mechanisms
Solution Approach 1:
The patent applies preliminary action by having the AP transmit channel estimation signals (NDP or training signals) before actual relay data transmission. This allows the relay STA and non-AP STA to pre-obtain channel information, including relay-to-STA channel estimates derived from AP-to-STA estimates, ensuring accurate channel knowledge is available before relay communication begins.
Solution Approach 2:
The patent uses the AP as an intermediary to facilitate relay channel estimation. The AP transmits reference signals that pass through the relay STA, enabling the receiving STA to estimate the relay-to-STA channel based on the known AP-to-STA channel characteristics. This intermediary approach allows indirect channel estimation without requiring separate dedicated relay estimation signals.
2Device complexity
If relay channel estimation is performed using existing mechanisms, then device complexity is reduced, but transmission reliability deteriorates due to inadequate channel information
Solution Approach 1:
The patent changes the parameter of channel information utilization by deriving relay channel estimates from AP channel estimates. Instead of treating relay channel estimation as a separate complex process, the system reuses existing channel estimation results and transforms them to obtain relay-specific channel information, maintaining low complexity while improving reliability.
Solution Approach 2:
The patent applies universality by making the channel estimation mechanism serve multiple functions: it estimates both the direct AP-to-STA channel and the relay-to-STA channel using the same reference signals. This multi-functional approach eliminates the need for separate estimation procedures while ensuring reliable channel information for relay operation.
3Measurement precision
If channel information is obtained through dedicated relay estimation, then channel accuracy is improved, but transmission delay increases due to additional signaling overhead
Solution Approach 1:
The patent merges relay channel estimation with existing channel sounding procedures. The same reference signals used for AP-to-STA channel estimation are simultaneously used for relay-to-STA channel estimation. This combining of estimation functions into a single unified process eliminates additional signaling overhead and associated delays while maintaining accurate channel information.
Solution Approach 2:
The patent performs relay channel estimation preliminarily during the initial channel sounding phase, before actual data transmission begins. By obtaining relay channel information in advance using the same timing as direct channel estimation, the system avoids any additional delay during the data transmission phase while ensuring accurate channel knowledge is available.
Data Source
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AI summary
The present disclosure relates to relay channel estimation in a wireless LAN system. According to an embodiment of the present disclosure, a method performed b y a station (STA) in a wireless local area network (LAN) system comprises the steps of: receiving, from an access point (AP), a relay trigger frame for a relay operation through a relay STA between the AP and the STA; on the basis of the reception of the relay trigger frame, monitoring for a signal for measuring, from the relay STA, a relay channel between the relay STA and the STA; on the basis of the signal for the measurement of the relay channel, acquiring relay channel information regarding the relay channel; and transmitting the relay channel information.