User Equipment D2D Link Adaptation Resource Allocation
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Solution Overview
Problem
Current LTE systems face challenges in accurately allocating radio resources for device-to-device (D2D) communications, as they do not account for the specific L1 control channel resources needed, leading to potential under or over-allocation and increased signaling overhead.
Innovation Solution
The method involves a user equipment (UE) establishing a D2D radio link and requesting radio resources for L1 control channel from the serving network node, allowing for direct communication and efficient link adaptation, with the UE indicating the required control channel resources through specific signaling formats and aggregation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the network schedules radio resources for D2D communication without accounting for L1 control channel resources, then resource allocation is simplified, but resource allocation accuracy deteriorates leading to under or over-allocation
Solution Approach 1:
The patent segments the resource allocation process into two distinct parts: data resource allocation handled by the network, and L1 control channel resource allocation handled autonomously by the UE. This segmentation allows each part to be optimized independently, with the UE accurately determining its own control channel resource needs based on link adaptation requirements without burdening the network with complex calculations.
Solution Approach 2:
The UE performs self-service by autonomously determining and allocating L1 control channel resources based on its own link adaptation needs. The UE calculates the required control channel resources independently and uses them for D2D communication without requiring network scheduling, thereby improving overall resource allocation accuracy while reducing network complexity.
2Measurement precision
If the network schedules both data and control channel resources for D2D communication, then resource allocation accuracy improves, but signaling overhead increases
Solution Approach 1:
The patent extracts the L1 control channel resource allocation function from the network scheduling process and assigns it to the UE. By taking out this specific function from the network, the patent reduces signaling overhead while maintaining accurate resource allocation, as the UE determines control channel resources based on its own link adaptation requirements without requiring extensive network signaling.
3Reliability
If the network handles link adaptation for D2D communication, then control reliability improves, but signaling overhead increases due to frequent channel state reports
Solution Approach 1:
The UE performs self-service link adaptation by autonomously determining L1 control channel resources and performing link adaptation itself. This eliminates the need for frequent channel state reports to the network, significantly reducing signaling overhead while maintaining reliable control through the UE's own link adaptation mechanisms.
4Quantity of substance
If UEs autonomously handle link adaptation for D2D communication, then signaling overhead is reduced, but resource allocation accuracy may deteriorate without proper control channel resources
Solution Approach 1:
The patent applies preliminary action by having the UE determine and allocate L1 control channel resources before performing autonomous link adaptation. The UE calculates the required control channel resources in advance based on expected link adaptation needs, ensuring that sufficient resources are available for accurate autonomous link adaptation without requiring additional signaling with the network.
Data Source
AI summary
A user equipment (UE) has established a first radio link with a serving network node and a second device-to-device (D2D) radio link directly with another user equipment (UE). In response to having D2D data to send to the other UE over the D2D radio link, the UE sends to the serving network node on the first link a request for radio resources for a layer 1 (L1) control channel; and in response to an assignment of D2D resources by the serving network node in reply to that request, the UE sends on the assigned D2D resources to the other UE the D2D data and the L1 control channel. In one example the request includes an indication of the UE's link adaptation for the L1 control channel such as format for a PDCCH or ePDCCH and/or aggregation level.