Network Node Spatial Separability for Wireless Interference Handling
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Solution Overview
Problem
In wireless networks employing Listen-Before-Talk (LBT) schemes, the 'hidden node' and 'exposed node' problems occur, leading to interference and reduced data throughput due to incorrect assessment of channel availability, where a device may transmit despite interference or refrain unnecessarily.
Innovation Solution
A network node determines the spatial separability of uplink signals from different wireless devices and transmits compatibility information in LBT-related messages, allowing devices to decide whether to transmit based on compatibility, thereby avoiding interference and optimizing channel usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a wireless device transmits based on LBT sensing alone, then the device can access the channel quickly, but interference occurs due to hidden node problems
Solution Approach 1:
The network node performs preliminary assessment of spatial separability between wireless devices before allowing channel access. By determining in advance whether devices are spatially separable (i.e., their uplink signals can be received without harmful interference), the network node can make informed decisions about channel access permissions, preventing interference before it occurs
Solution Approach 2:
The network node acts as an intermediary between wireless devices and the shared channel. It receives spatial separability information from devices, assesses compatibility, and provides feedback (LBT-related messages with compatibility information) that mediates channel access decisions, thereby coordinating transmissions to avoid interference while maintaining efficient access
2Object-affected harmful factors
If a wireless device refrains from transmission when sensing busy channel, then interference is avoided, but data throughput decreases due to exposed node problems
Solution Approach 1:
The network node provides feedback in the form of LBT-related messages containing compatibility information to wireless devices. This feedback enables devices to distinguish between channels that are truly unavailable (causing interference) and channels that appear busy but would not cause interference at the network node, allowing devices to transmit when compatible even if the channel appears busy
Solution Approach 2:
The network node performs preliminary assessment of spatial separability and provides compatibility information to devices before channel access decisions are made. This preliminary action allows devices to make informed transmission decisions without unnecessarily refraining from transmission, thereby maintaining data throughput while avoiding interference
Data Source
AI summary
A network node (300), a wireless device (304) and methods therein, for handling interference in a wireless network where a Listen-Before-Talk, LBT, scheme is employed to control transmissions. The network node (300) determines whether a first wireless device (302) is compatible with a second wireless device (304) at a serving network node (300) so that uplink signals transmitted (3:1A, 3:2A) from the wireless devices (302, 304) are spatially separable at the serving network node (300). An LBT-related message is then transmitted (3:4A) to the first wireless device (302), which message indicates that the wireless devices (302, 304) are compatible or incompatible at the serving network node (300). The second wireless device (304) is then able to detect (3:4A), i.e. overhear, the LBT-related message and use it as a basis for deciding (3:5) whether to perform a transmission or not. The second wireless device (304) can thus decide to transmit when the compatibility information indicates that the wireless devices (302, 304) are compatible, or refrain from transmission when the compatibility information indicates that the wireless devices (302, 304) are incompatible.