Wireless Medium Access via Signal Strength Grouping
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Solution Overview
Problem
In densely deployed wireless networks, the 'exposed terminal' problem occurs where nodes refrain from accessing the communication medium due to overhearing transmissions from neighboring nodes, leading to inefficient energy usage and potential fairness issues in medium access.
Innovation Solution
Implementing a method where STAs measure the received power of Beacon frames and are grouped based on this power, allowing simultaneous medium access within specific groups across overlapping BSSs, using a Restricted Access Window (RAW) mechanism to coordinate access periods and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nodes in wireless networks use traditional contention-based medium access, then all nodes can potentially access the communication medium, but nodes may unnecessarily back off due to exposed terminal problem leading to energy waste and reduced productivity
Solution Approach 1:
The patent segments the coverage area of each access point into multiple regions (first region, second region, third region) based on received signal strength. Nodes are categorized into different groups according to which region they fall into. This segmentation allows the system to apply different medium access rules to different node groups, enabling nodes in non-overlapping regions to access the medium simultaneously without causing interference, thereby reducing unnecessary back-offs and improving overall medium access efficiency while conserving energy.
2Productivity
If nodes back off to avoid interference from neighboring transmissions, then interference is reduced, but medium access efficiency and productivity decrease due to unnecessary back-offs
Solution Approach 1:
The patent applies local quality by assigning different medium access permissions to nodes in different spatial regions. Nodes in the first region (closer to their associated AP and not overlapping with neighboring BSS) are permitted to access the medium simultaneously with nodes in other non-overlapping regions. Nodes in overlapping regions are restricted from simultaneous access. This localized differentiation allows the system to maximize medium utilization in non-interfering areas while preventing interference in overlapping areas, thus improving overall productivity without causing harmful interference.
3Productivity
If all nodes are allowed to access the medium simultaneously, then productivity increases, but interference and harmful factors increase due to exposed terminal problems
Solution Approach 1:
The patent segments the network into multiple access groups based on spatial region classification. Each group is assigned specific time periods during which they are permitted to access the communication medium. This segmentation ensures that only nodes in non-overlapping regions transmit simultaneously, preventing interference while maximizing medium utilization. The systematic allocation of access periods to different groups enables high productivity without generating harmful interference.
4Quantity of substance
If the network uses dense node deployment to increase capacity, then more nodes can access the network, but the exposed terminal problem becomes more pronounced leading to energy waste
Solution Approach 1:
The patent segments the network into multiple access groups based on spatial region classification, allowing dense node deployment to be managed efficiently. By categorizing nodes into different groups according to their received signal strength and spatial location, the system enables simultaneous medium access for nodes in non-overlapping regions even in dense deployments. This prevents the exposed terminal problem from causing unnecessary back-offs and energy waste, while still supporting a large number of nodes in the network.
Data Source
AI summary
Methods, apparatus and program products are disclosed for allowing wireless devices in two wireless access networks whose coverage areas overlap to communicate with their respective access nodes. Groups may be assigned to wireless devices in the access networks and the groups may be used by wireless devices in the access networks to determine whether to access a communication medium or not. Received powers may also be used by wireless devices in the access networks to determine whether or not to access a communication medium. A wireless device in a first access network can determine whether to access (e.g., compete for access to) the communication medium by comparing a measured power of transmission from a second access node with an indication of a minimum received power above which wireless devices in a second access network formed by a second access node are allowed to contend for access to the communication medium.