Wireless Power Transmission Channel Access for WLAN Coexistence
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Solution Overview
Problem
Wireless power transmission systems face interference issues when operating in shared wireless medium environments, particularly when using the same or overlapping radio bands as WLANs, leading to challenges in coexistence with existing equipment.
Innovation Solution
The implementation of a wireless power transmission system that transmits power signals in a manner that coexists with WLAN equipment by using non-interfering channels or emulating peer wireless network devices to access channels, allowing for simultaneous wireless power and data transmission without interfering with other wireless devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wireless power transmission systems use the same or overlapping radio bands as WLANs, then wireless power transmission can be achieved, but interference with data transmissions occurs
Solution Approach 1:
The system segments the wireless medium access by implementing time-division multiplexing, where wireless power transmission and WLAN data transmissions are separated into different time slots. The WPTS monitors channel occupancy and transmits power signals only during periods when WLAN activity is detected to be minimal or absent, thereby eliminating interference while maintaining wireless power transmission capability.
Solution Approach 2:
The WPTS employs dynamic channel access mechanisms that adapt to real-time WLAN activity. The system continuously monitors the wireless medium for WLAN transmissions and dynamically adjusts its transmission schedule, deferring power transmission until the channel is clear or transmitting at reduced power levels during shared access periods, thus resolving the interference contradiction.
2Power
If wireless power signals are transmitted in shared wireless medium environments, then power transmission capability is achieved, but coexistence with existing equipment becomes difficult
Solution Approach 1:
The system introduces an intermediary layer of protocol emulation and channel access coordination. The WPTS emulates WLAN protocol behavior to gain fair access to the shared medium, using virtual carriers sense and transmission deferral mechanisms that mirror WLAN operations, thereby enabling peaceful coexistence with existing WLAN equipment while maintaining full wireless power transmission capability.
Solution Approach 2:
The WPTS dynamically changes operational parameters including transmission power levels, time slot allocation, and frequency selection based on detected WLAN activity. By adjusting these parameters in real-time, the system maintains optimal power transmission performance while adapting to the presence of existing WLAN equipment, achieving both high power capability and environmental coexistence.
3Productivity
If wireless power transmission and WLAN data transmission occur simultaneously in the same radio band, then resource utilization is improved, but signal interference increases
Solution Approach 1:
The system implements periodic time-division multiplexing where wireless power transmission and WLAN data transmission are allocated to alternating time slots. During designated power transmission slots, the WPTS transmits at full power while WLAN access is deferred, and during WLAN slots, data transmission occurs without power interference. This periodic separation maintains high overall resource utilization while ensuring signal quality reliability for both systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the coexistence of wireless power transmission systems with WLANs and other equipment by minimizing interference, ensuring reliable operation in shared wireless medium environments through strategic channel selection and protocol emulation.
Implementation Method 1
Wireless power transmission systems (WPTS) employing RF signals may utilize portions of the licensed RF spectrum, including 2.4 GHz and 5 GHz radio bands
Data Source
AI summary
Support of coexistence of wireless transmission equipment in shared wireless medium environments is disclosed, which is applicable to various types of wireless transmission equipment. For instance, a wireless power transmission system (WPTS) delivers power to wireless power receiver clients via transmission of wireless power signals using one or more frequencies and/or channels within shared wireless medium environments in which other wireless equipment is operating, such as access points and stations in wireless local area networks (WLANs). The WPTS is configured to co-exist with the operations of the other wireless equipment within the shared wireless medium environment by adapting its transmission operations to utilize frequencies or channels that do not interfere with other equipment and/or implementing co-channel and shared channels operations under which access to channels is implemented using standardized WLAN protocols such as PHY and MAC protocols used for 802.11 (Wi-Fi™) networks.