Cooperative Hidden Node Detection via Intermediary Signaling
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Solution Overview
Problem
Wireless communication systems face interference from hidden nodes, where a transmitting device outside the energy detection or preamble detection radius of another node can concurrently transmit, causing interference to a receiving user equipment (UE) due to insufficient energy detection, leading to disrupted communications.
Innovation Solution
Implementing techniques for cooperative hidden node identification and management, where a serving transmitting device collaborates with neighboring devices to detect and mitigate hidden node interference through coordinated preamble transmissions, scheduling decisions, and modulation and coding scheme selection, using measurement reports from the UE to identify and address the interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transmitter performs LBT procedure by measuring energy on the wireless channel, then it can detect active channels and avoid interference, but it cannot detect hidden nodes that are outside its energy detection radius
Solution Approach 1:
The patent introduces a coordinating transmitter as an intermediary that acts as a proxy detector for hidden nodes. This coordinating transmitter is positioned such that it can detect energy from hidden nodes that are outside the energy detection radius of the original transmitter. The coordinating transmitter then communicates detection information to the original transmitter, enabling indirect detection of hidden nodes through this intermediary device.
Solution Approach 2:
The patent combines the detection capabilities of multiple transmitters by having them share energy detection information. The coordinating transmitter merges its detection results with those of the original transmitter, creating a composite view of channel conditions that includes both visible and hidden nodes. This merging of detection data from multiple sources expands the effective detection coverage beyond what a single transmitter can achieve.
2Productivity
If two transmitters are sufficiently distant from each other, then they can concurrently transmit without detecting each other's energy, but this creates hidden node interference at receivers located between them
Solution Approach 1:
The patent implements a feedback mechanism where the coordinating transmitter monitors the wireless channel and communicates detection information back to the original transmitter. When the coordinating transmitter detects energy from a hidden node or determines that concurrent transmission would cause interference, it provides feedback to the original transmitter to adjust its transmission timing or power, thereby preventing reception quality degradation while maintaining concurrent transmission capability when safe.
Solution Approach 2:
The patent performs preliminary detection and coordination before concurrent transmissions begin. The coordinating transmitter assesses channel conditions and potential hidden node interference in advance, and only permits concurrent transmissions when detection results indicate safety. This preliminary action ensures that productivity gains from concurrent transmission do not compromise reception quality.
3Ease of operation
If the LBT procedure uses a threshold energy level to determine channel availability, then it provides a clear decision criterion, but it fails to account for hidden nodes whose energy remains below the threshold
Solution Approach 1:
The patent makes the LBT procedure universal by having both the original transmitter and the coordinating transmitter perform energy detection and share results. The coordinating transmitter effectively performs the LBT function on behalf of the original transmitter for directions where hidden nodes may be present. This multi-functional approach maintains the simplicity of threshold-based decision-making while extending its effectiveness to cover hidden nodes that would otherwise remain undetected.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described that provide for detection and management of hidden node interference. A user equipment (UE) may provide measurement reports to a serving transmitting device to help identify the hidden node interferer in response to detecting hidden node interference. The serving transmitting device may collaborate with one or more neighboring transmitting devices, such as other transmitting devices of an operator of a wireless communications system, to identify one or more of the neighboring transmitting devices that are within an energy detect or preamble detect radius of the hidden node. The serving transmitting device may coordinate with the neighboring transmitting device(s) to determine when the hidden node may transmit, to transmit coordinated preamble transmissions to prevent the hidden node from transmitting during a transmission, or to identify a modulation and coding scheme for the transmission.