Group Coordinator Scheduling for D2D Cellular Latency
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Solution Overview
Problem
Current ProSe (LTE D2D) concepts fail to support 2-hop group cooperative transmission due to missing components for creating groups with cellular UL capabilities, handling identities, and performing scheduling and prioritization, resulting in additional latency during dynamic scheduling procedures.
Innovation Solution
A method is introduced that combines scheduling requests and buffer status reports for both D2D and cellular links, allowing a group coordinator device to request and receive grants in a single transmission, reducing scheduling latency by enabling simultaneous dynamic scheduling for D2D and cellular links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If separate scheduling procedures are used for D2D and cellular links, then resource allocation can be optimized for each link independently, but scheduling latency increases due to multiple separate requests and grants
Solution Approach 1:
The patent combines separate scheduling requests and buffer status reports for D2D and cellular links into a single unified message transmitted by the group coordinator. This merging eliminates the need for multiple separate scheduling procedures, thereby reducing scheduling latency while maintaining the ability to allocate resources for both links independently through a coordinated grant mechanism.
2Productivity
If a group coordinator handles both D2D and cellular transmissions, then resource allocation efficiency improves, but the complexity of managing grants and scheduling increases
Solution Approach 1:
The group coordinator device is designed to perform multiple functions: it acts as both a D2D communication node and a cellular uplink transmission node. By consolidating these roles in a single device, the system achieves more efficient resource allocation while the base station manages the complexity of grant distribution through a unified scheduling approach rather than requiring complex inter-device coordination.
Solution Approach 2:
The base station serves as an intermediary that receives unified scheduling requests from the group coordinator and returns coordinated grants that cover both D2D and cellular resources. This mediator approach allows the group coordinator to benefit from centralized resource management without bearing the full complexity of managing separate scheduling procedures for both links.
3Loss of time
If combined scheduling request is sent for both D2D and cellular links, then scheduling latency is reduced, but the message size and processing complexity increase
Solution Approach 1:
The scheduling request and buffer status report messages for both D2D and cellular links are merged into a single transmission from the group coordinator to the base station. This combination reduces the number of round-trip communications required, thereby reducing scheduling latency while the base station processes the unified message using integrated resource allocation algorithms.
Data Source
AI summary
A method for enabling group transmission among devices capable of Device to Device, D2D, communication in network having a base station. The devices have a group coordinator may directly communicate with one another over a D2D link. The group coordinator device is arranged to communicate with the base station over a cellular link. The group coordinator device sends a Scheduling Request, SR, message requesting grants for both D2D and cellular transmission. The group coordinator device transmits a Buffer Status Report, BSR and receives a grant for said the D2D and the cellular transmissions based on the transmitted BSR. The group coordinator device distributes the received grant to the plurality of devices.