D2D Resource Allocation via RS Signal Strength Thresholds
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Solution Overview
Problem
Existing radio communications networks face challenges in safely introducing Device-to-Device (D2D) communication on downlink cellular resources, as existing solutions do not adequately protect cellular downlink Reference Signals (RS) from D2D transmissions and vice versa, leading to potential interference.
Innovation Solution
User Equipment (UE) measures received signal strengths of RS from network nodes, identifies suitable downlink cellular resources, and reports them to a network node, which then assigns orthogonal resources for D2D communication, ensuring minimal interference with cellular RS transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If D2D communication is introduced on downlink cellular resources, then capacity and spectrum utilization are improved, but interference between D2D transmissions and cellular Reference Signals occurs
Solution Approach 1:
The downlink cellular resources are segmented into two distinct subsets: a first subset reserved for cellular Reference Signal transmissions and a second subset allocated for D2D communications. This segmentation ensures that D2D transmissions and cellular RS transmissions occur on separate resources, eliminating mutual interference while maintaining high spectrum utilization through resource reuse.
Solution Approach 2:
Different quality requirements are applied to different resource subsets: the first subset is optimized for cellular RS transmissions with specific signal strength thresholds, while the second subset is optimized for D2D communications. The network node determines these subsets based on local signal conditions and interference measurements, ensuring each resource type receives appropriate quality treatment.
2Ease of operation
If D2D communication is enabled without resource separation, then ease of operation is improved, but reliability of cellular RS reception deteriorates
Solution Approach 1:
The network node performs preliminary actions by determining and reserving the first subset of downlink resources for cellular RS transmissions before allocating the second subset for D2D communications. The UE also performs preliminary measurements of received signal strengths and reports suitable resources to the network node in advance, ensuring reliable cellular RS reception is established before D2D operations begin.
Solution Approach 2:
The network node acts as an intermediary that coordinates between cellular and D2D operations. It receives measurements from the UE, determines the appropriate resource subsets, and provides feedback to the UE about which resources are suitable for D2D communication. This intermediary coordination ensures both cellular reliability and D2D functionality without direct conflict.
3Productivity
If all downlink resources are used for D2D communication, then productivity is improved, but measurement precision of cellular RS is reduced
Solution Approach 1:
The downlink resources are divided into a first subset dedicated to cellular RS transmissions and a second subset for D2D communications. This segmentation ensures that measurement-grade precision resources are protected for cellular operations while allowing maximum resource utilization for D2D productivity.
Solution Approach 2:
The network node changes the parameter of resource allocation by identifying specific subsets of downlink resources based on received signal strength measurements and threshold comparisons. Resources with signal strengths above the threshold are designated for cellular RS (maintaining measurement precision), while other resources are allocated for D2D (maximizing productivity).
Data Source
AI summary
A method performed by a first User Equipment, UE, for enabling Device-to-Device, D2D, communication with a second UE in a radio communications network is provided. The first UE is configured to perform the D2D communication on downlink cellular resources in the radio communications network. The first UE measures received signal strengths of Reference Signals, RS, on downlink cellular resources from one or more network nodes in the radio communications network. The first UE then determines a first subset of downlink cellular resources for which the measured received signal strength of RS is above or equal to a threshold value. Also, the network node transmits information indicating the determined first subset of downlink cellular resources to a network node serving the first UE in the radio communications network in order to enable the D2D communication.