Uplink Signal Transmission via Sensing-Based Frequency Synchronization
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Solution Overview
Problem
Current CSMA-based wireless communication systems face challenges in increasing data throughput without expanding bandwidth, particularly in supporting uplink MU-MIMO transmission due to unsynchronized frequency and timing offsets among devices.
Innovation Solution
A sensing-based frequency synchronization scheme is introduced, where stations sense the medium occupied by other devices to determine if they can perform uplink MU-MIMO transmission, adjusting their frequency and timing synchronization accordingly, allowing them to transmit on the same medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stations transmit uplink signals simultaneously on the same medium, then data throughput increases, but frequency and timing synchronization becomes difficult to maintain
Solution Approach 1:
The system performs frequency offset estimation and timing synchronization as preliminary actions before allowing simultaneous uplink transmissions. The access point estimates frequency offsets of multiple stations beforehand and provides compensation information, ensuring that stations are pre-synchronized before multiplying their transmissions on the same medium.
Solution Approach 2:
The access point continuously monitors uplink signals, estimates frequency offsets, and provides feedback information to stations for synchronization adjustment. This closed-loop feedback mechanism maintains frequency and timing synchronization even as multiple stations transmit simultaneously, resolving the contradiction between increased throughput and synchronization precision.
2Reliability
If CSMA protocol is used to avoid collisions, then transmission reliability improves, but medium utilization efficiency decreases
Solution Approach 1:
The system changes the operational parameters of CSMA by allowing multiple stations to transmit on the same medium simultaneously through frequency offset compensation. This parameter change enables the medium to carry multiple signals at once, increasing utilization efficiency while the access point maintains transmission reliability through advanced signal separation and frequency offset management.
Data Source
AI summary
The present invention provides an uplink signal transmission method and apparatus. A method for transmitting an uplink signal to an access point (AP) by means of a station (STA) in a Wireless local area network (WLAN) system comprises: sensing a medium being occupied by another STA; and transmitting the uplink signal to the AP on the medium being occupied by another STA.