Dynamic Channel Bandwidth Adjustment in Wireless Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In IEEE 802.11ah wireless communication systems, there is a challenge of data loss due to collisions between long-range and short-range BSSs, as some access points and stations do not hear traffic in overlapping short-range BSSs, leading to inefficient channel usage and increased contention in the 900 MHz band.
Innovation Solution
A method is introduced to dynamically adjust channel bandwidth by using a usable channel indicator in response frames, allowing devices to inform each other about the usability of narrow band channels based on SNR, SINR, RSSI, and other factors, enabling reduction or increase of channel bandwidth in real-time to avoid unusable channels and minimize data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If long-range BSS uses narrow 1 or 2 MHz channel to extend coverage area, then coverage area is improved, but channel bandwidth utilization deteriorates due to overlap with short-range BSSs
Solution Approach 1:
The patent implements dynamic channel bandwidth adjustment where the long-range BSS adapts its channel bandwidth based on real-time detection of short-range BSS traffic. The system transitions from a fixed narrow channel to a dynamically adjustable bandwidth that expands or contracts according to detected interference conditions, resolving the contradiction between maintaining coverage area and optimizing channel utilization.
Solution Approach 2:
The patent employs feedback mechanisms where the long-range BSS continuously monitors the wireless medium for traffic from short-range BSSs. Based on this feedback information, the system adjusts its channel bandwidth accordingly - reducing bandwidth when short-range traffic is detected to avoid collisions, and expanding when the medium is clear, thus optimizing both coverage and channel utilization.
2Use of energy by moving object
If devices do not hear traffic in overlapping short-range BSSs, then energy consumption is reduced, but data loss increases due to collisions
Solution Approach 1:
The patent applies preliminary action by having the long-range BSS perform channel assessment and detect short-range traffic before initiating data transmission. This advance detection allows the system to adjust channel bandwidth proactively, preventing collisions before they occur while maintaining energy efficiency by only activating additional bandwidth when necessary.
Solution Approach 2:
The patent implements preliminary anti-action by detecting the presence of short-range BSS traffic in advance and taking countermeasures (adjusting channel bandwidth) to prevent harmful collisions. This proactive approach allows the long-range BSS to neutralize potential interference before it causes data loss, maintaining both energy efficiency and reliability.
3Device complexity
If channel bandwidth is fixed, then device complexity is reduced, but adaptability deteriorates in overlapping BSS environments
Solution Approach 1:
The patent changes the channel bandwidth parameter dynamically based on environmental conditions. The system monitors traffic patterns and adjusts the channel bandwidth parameter in response to detected short-range BSS activity, enabling adaptability without requiring complex reconfiguration of the entire system architecture.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A method of reducing the usable channel bandwidth and increasing the channel bandwidth at run time is provided. The method allows a receiving wireless communications device to inform its corresponding transmitting communications device to either increase, reduce, or maintain the number of usable narrow band channels for the succeeding frame exchange. In a wireless communications channel, channel reduction is accomplished by using a usable channel indicator in a response frame responding to the preceding receiving frame. The usable channel indicator is the means for the receiving communications device to inform the transmitting communications device the preferred narrow band channels that it deems having good channel characteristics.