Wireless Channel Access via Power-Based Station Grouping
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Solution Overview
Problem
Wireless communications networks face inefficiencies due to overlapping basic service sets (OBSS) leading to increased collisions and interference, particularly in dense deployments, where existing mechanisms like fractional CSMA/CA and power control do not adequately address the hidden node problem and interference mitigation.
Innovation Solution
The method involves grouping stations into two categories based on minimum transmission power levels and allocating non-overlapping time intervals for each group to access the communications channel, allowing high-power stations to transmit during specific times while low-power stations transmit during other times, thereby minimizing interference and collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same channel is reused in dense deployments to increase capacity, then spectrum efficiency is improved, but co-channel interference increases causing collisions and poor system performance
Solution Approach 1:
The patent segments the transmission power levels into different categories (high-power and low-power groups) and assigns different channel access opportunities to each segment. This segmentation allows the system to tolerate higher interference levels for low-power stations while protecting high-power transmissions, thereby enabling channel reuse in dense deployments without severe collision penalties.
Solution Approach 2:
The patent changes the parameter of transmission power by grouping stations into different power levels and dynamically adjusting channel access rights based on power category. This parameter change enables the system to differentiate between stations causing significant interference versus those causing minimal interference, allowing more aggressive channel reuse while maintaining performance for critical transmissions.
2Reliability
If transmission power is increased to overcome interference and ensure successful transmission, then reliability is improved, but interference to other BSSs increases worsening co-channel performance
Solution Approach 1:
The patent applies local quality by assigning different channel access privileges to stations based on their local transmission power characteristics. High-power stations receive more protected access opportunities while low-power stations accept more interference tolerance, creating a localized quality differentiation that resolves the contradiction between ensuring reliable transmission and minimizing interference to neighboring BSSs.
Solution Approach 2:
The patent changes the power parameter by categorizing stations into high-power and low-power groups, and accordingly changes their channel access parameters. This dual parameter change (power level and access opportunity) allows the system to achieve reliable transmission for high-power stations while limiting their interference impact through controlled access timing, and simultaneously allows low-power stations to utilize remaining capacity without causing severe interference.
3Productivity
If DSC is used to counteract low signal power situations, then spectrum efficiency is improved, but the fundamental issue of excessive interference due to lack of power control remains unaddressed
Solution Approach 1:
The patent extends the DSC concept by segmenting stations into power-based groups and providing differentiated channel access. While basic DSC only adjusts sensitivity thresholds, this patent segments the transmitter population and assigns unequal access rights, thereby addressing the root cause of excessive interference through power-controlled access differentiation rather than merely adjusting reception sensitivity.
Solution Approach 2:
The patent changes both the power parameter and the channel access parameter simultaneously, whereas traditional DSC only changes the detection threshold parameter. By changing transmission power categorization and linking it to access opportunities, the patent addresses excessive interference at its source rather than compensating for it at the receiver, thereby fundamentally solving the power control deficiency in uncoordinated deployments.
Data Source
AI summary
There is provided access to a communications channel in a wireless communications network. Stations (STAs) associated with an access point (AP) are grouped in at least two groups of STAs, each group being associated with a minimum transmission power level needed by the AP to communicate with the STAs in that group. A first time interval is allocated for a first group of STAs associated with highest minimum transmission power to access the communications channel concurrently with a third time interval being allocated by another AP for a third group of STAs associated with lowest minimum transmission power level needed by said another AP to communicate with the third group of STAs to access the communications channel. A second time interval, non-overlapping with the first time interval, is allocated for a second group of STAs associated with lowest minimum transmission power to access the communications channel concurrently with a fourth time interval being allocated by said another AP for a fourth group of STAs associated with highest minimum transmission power level needed by said another AP to communicate with the fourth group of STAs to access the communications channel.