MU Ranging Protocol Grouping for Inter-STA Interference
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Solution Overview
Problem
Current multi-user ranging measurement protocols face challenges in indoor navigation due to signal interference and power imbalance issues, particularly the 'near-far problem' which affects accurate channel estimation and inter-STA interference, limiting the number of users that can be supported in a single burst of sounding.
Innovation Solution
The proposed solution involves modifying the MU ranging protocol to form uplink sounding groups based on received power levels, allowing STAs with similar powers to transmit in the same time slot and those with different powers to transmit in separate slots, reducing inter-STA interference and enabling support for a larger number of users by separating UL NDP sounding frames in the time domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple STAs transmit UL NDP sounding frames simultaneously in a single time slot, then the number of supported users increases, but inter-STA interference and channel estimation accuracy deteriorate
Solution Approach 1:
The patent segments the uplink sounding process by dividing STAs into multiple groups based on their received power levels. Each group transmits its UL NDP sounding frames in a separate time slot, preventing simultaneous transmissions that cause interference. This segmentation resolves the contradiction by allowing more users to be supported across multiple slots while maintaining accurate channel estimation within each slot through isolated transmissions.
2Quantity of substance
If STAs with different received power levels transmit in the same time slot, then the number of supported users increases, but the near-far problem exacerbates causing measurement errors
Solution Approach 1:
The patent applies local quality by categorizing STAs into different groups based on their individual received power levels. STAs with similar power levels are grouped together and transmit in the same time slot, while STAs with different power levels are separated into different slots. This ensures that within each time slot, all transmitting STAs have comparable power levels, eliminating the near-far problem and maintaining measurement precision while still supporting multiple users across all groups.
3Device complexity
If a single time slot is used for uplink sounding, then the measurement process is simplified, but the number of supported users is limited due to interference
Solution Approach 1:
The patent segments the uplink sounding process by dividing STAs into multiple groups based on their received power levels. Each group transmits its UL NDP sounding frames in a separate time slot, preventing simultaneous transmissions that cause interference. This segmentation resolves the contradiction by allowing more users to be supported across multiple slots while maintaining accurate channel estimation within each slot through isolated transmissions.
4Loss of time
If all STAs transmit simultaneously in one burst, then the measurement time is reduced, but inter-STA interference increases limiting accuracy
Solution Approach 1:
The patent segments the uplink sounding process by dividing STAs into multiple groups based on their received power levels. Each group transmits its UL NDP sounding frames in a separate time slot, preventing simultaneous transmissions that cause interference. This segmentation resolves the contradiction by allowing more users to be supported across multiple slots while maintaining accurate channel estimation within each slot through isolated transmissions.
Data Source
AI summary
For example, an apparatus may include circuitry and logic configured to cause a wireless communication station (STA) to determine a plurality of uplink (UL) sounding groups of STAs; transmit at least one trigger frame to at least one UL sounding group of the plurality of UL sounding groups to trigger a measurement procedure with the UL sounding group, the trigger frame including one or more Identifiers (IDs) to identify one or more STAs of the UL sounding group; to receive one or more UL Null Data Packet (NDP) sounding frames from the one or more STAs of the UL sounding group in response to the trigger frame; to transmit a downlink (DL) NDP Announcement (NDP-A) frame to the plurality of UL sounding groups; and to transmit a DL NDP sounding frame to the plurality of UL sounding groups.