Network Node Physical Channel Multiplexing for D2D Interference
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Solution Overview
Problem
In mixed wireless networks, the coexistence of cellular and Device-to-Device (D2D) systems leads to significant co-channel and inter-channel interference, which hampers efficient communication by causing collisions and interference between statically preconfigured cellular and D2D transmissions.
Innovation Solution
The network node employs time division multiplexing and frequency division multiplexing to separate cellular and D2D channels, scheduling them at different times and frequencies to avoid interference, and dynamically adjusts resource allocation based on interference measurements to minimize interference and optimize spectrum reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cellular and D2D channels are statically preconfigured to use the same frequency resources, then spectrum reuse efficiency is improved, but co-channel interference increases causing communication collisions
Solution Approach 1:
The patent implements dynamic resource allocation where the network node continuously monitors interference levels between cellular and D2D channels and adjusts resource allocation in real-time. When interference exceeds thresholds, the system dynamically switches between frequency division multiplexing and time division multiplexing modes, transforming the static resource allocation into a dynamic adaptive system that resolves the contradiction between spectrum reuse and interference avoidance.
Solution Approach 2:
The system changes key parameters including frequency resource allocation, time slot assignment, and multiplexing mode selection based on measured interference conditions. By adjusting these parameters dynamically, the system optimizes spectrum reuse efficiency while maintaining interference levels below harmful thresholds, directly addressing the technical contradiction.
2Object-affected harmful factors
If cellular and D2D channels are separated using frequency division multiplexing, then interference is reduced, but spectrum reuse efficiency decreases
Solution Approach 1:
The patent implements periodic interference measurement and evaluation cycles where the network node continuously monitors channel conditions, measures interference levels, and adjusts multiplexing strategies at regular intervals. This periodic action allows the system to maintain frequency division multiplexing for interference reduction while periodically optimizing spectrum reuse by switching to time division multiplexing when conditions permit, thus resolving the contradiction between interference reduction and spectrum efficiency.
Solution Approach 2:
The system employs feedback mechanisms where interference measurement results are fed back to the network node, which then adjusts resource allocation decisions. This closed-loop control enables the system to maintain appropriate separation between cellular and D2D channels when needed while maximizing spectrum reuse when interference levels are acceptable, balancing the contradictory requirements.
3Object-affected harmful factors
If time division multiplexing is used to separate cellular and D2D transmissions, then interference collisions are avoided, but communication latency increases
Solution Approach 1:
The patent applies time division multiplexing selectively rather than universally - only when interference measurements indicate that collision avoidance is necessary. When channel conditions are favorable and interference levels are low, the system allows partial overlap or uses frequency division multiplexing instead, thus avoiding the full time separation penalty while still preventing harmful collisions, effectively resolving the contradiction between collision avoidance and latency reduction.
Data Source
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AI summary
A method in a network node for multiplexing a physical channel 400, between the network node and devices comprised in a mixed wireless network, wherein the mixed wireless network further comprises a cellular network comprising one or more cellular channels and a Device-to-Device, D2D, network comprising one or more D2D channels, the method comprising: time division multiplexing the physical channel 400 between a first group of cellular channels and a first group of D2D channels, and frequency division multiplexing the physical channel 400 between a second group of cellular channels and the first group of D2D channels.