Coordinated Spatial Reuse Scheduling to Limit OBSS Interference
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Solution Overview
Problem
Existing wireless networks face interference issues due to the lack of coordination between access points (APs) belonging to different basic service sets (BSSs), limiting the extent to which overlapping BSSs can operate in proximity and affecting transmission efficiency.
Innovation Solution
A method for coordinating spatial reuse transmissions among multiple APs by selecting other APs for a coordinated access point transmission session, sharing a transmission opportunity (TXOP), and scheduling uplink or downlink transmissions based on signal strengths and interference levels to minimize packet loss and maximize medium utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial reuse techniques are used to allow APs to transmit data in the presence of OBSS interference, then transmission efficiency is improved, but the lack of coordination between SR transmissions and OBSS transmissions limits the extent to which OBSSs can operate in the vicinity of one another
Solution Approach 1:
The patent merges previously separate coordination functions into a unified coordinated AP transmission session framework. Multiple APs from different BSSs are combined into a single coordinated transmission opportunity (TXOP), allowing them to transmit simultaneously with proper coordination. This resolves the contradiction by enabling both high transmission efficiency through spatial reuse and proper coordination through the unified session management mechanism.
Solution Approach 2:
The patent introduces dynamic scheduling within the coordinated TXOP, where the serving AP can allocate different time portions to different participating APs based on real-time conditions. The start times for UL/DL transmissions are dynamically adjusted using offset values, allowing the system to adapt to varying interference conditions while maintaining high transmission efficiency throughout the coordinated session.
2Device complexity
If multiple APs operate independently without coordination, then device complexity is reduced, but interference between overlapping BSSs increases and limits operational proximity
Solution Approach 1:
The patent introduces a serving AP as an intermediary that coordinates transmissions among multiple participating APs. The serving AP manages the coordinated TXOP, schedules transmissions for other APs, and handles interactions with STAs. This intermediary approach enables multiple APs to operate in proximity with reduced interference while avoiding the complexity of full mesh coordination among all APs.
Solution Approach 2:
The patent segments the coordinated TXOP into distinct time portions, each allocated to a specific participating AP for UL or DL transmissions. This time-division segmentation allows multiple APs to share the wireless medium efficiently while preventing interference through proper temporal separation, thus reducing harmful interference without requiring complex simultaneous coordination.
3Productivity
If transmission start times are aligned among APs, then medium utilization is maximized, but packet loss may increase due to decoding conflicts
Solution Approach 1:
The patent changes the timing parameter by introducing configurable offset values for transmission start times. Instead of fixed alignment, the system dynamically adjusts start times by adding offsets to the base time, allowing optimization of both medium utilization and reliability based on specific operational conditions. This parameter adjustment resolves the contradiction by enabling flexible timing control.
Solution Approach 2:
The patent implements periodic transmission opportunities within the coordinated session, where UL and DL transmissions are scheduled in periodic intervals. This periodic structure allows the system to maximize medium utilization through regular transmission cycles while maintaining reliability by ensuring proper decoding intervals between periodic transmissions from different APs.
Data Source
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AI summary
In some implementations, a first access point (AP) selects one or more other APs for participation with the first AP in a coordinated access point transmission session. The first AP obtains a transmission opportunity (TXOP), and transmits a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from the selected APs, the scheduling information indicating a respective start time for the UL or DL transmissions to or from the selected APs, at least two of the start times being offset from one another by a time period associated with decoding a preamble of a wireless packet. The first AP transmits or receives wireless packets to or from one or more associated stations (STAs) at least partially concurrently with the transmission or reception of wireless packets by the selected APs to or from their respective associated STAs based on the scheduling information.