Cooperative Distributed Scheduling for D2D Communication
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Solution Overview
Problem
In wireless communication systems, device-to-device (D2D) communication often experiences resource collisions as multiple UE devices randomly select resources, leading to inefficiencies as the number of devices increases, particularly in contention-based modes.
Innovation Solution
The implementation of a Cooperative Distributed Scheduling (CDS) technique, where UE devices transmit a preferred transmission indicator (PTI) based on conditions like buffer size and Quality of Service (QoS), causing other devices to delay or refrain from transmitting scheduling assignments (SA) to minimize resource collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If UE devices randomly select resources from an allocated pool for D2D communication, then resource allocation is simple and decentralized, but resource collisions increase as the number of UE devices increases
Solution Approach 1:
The system performs preliminary actions by having UE devices transmit preferred transmission indicators before actual resource selection. This allows devices to declare their transmission intentions in advance, enabling other devices to adjust their resource selection to avoid collisions before they occur, rather than dealing with collisions after random selection.
Solution Approach 2:
The system implements feedback mechanisms where UE devices monitor preferred transmission indicators from other devices and adjust their own resource selection accordingly. This feedback loop allows devices to learn about resource preferences of others and modify their behavior to minimize collisions while maintaining decentralized operation.
2Reliability
If UE devices transmit preferred transmission indicators and delay scheduling assignments based on received indicators, then resource collisions are reduced, but transmission delay increases
Solution Approach 1:
The system applies partial action by having UE devices delay transmission only when necessary - specifically when they receive preferred transmission indicators from other devices. Devices can choose to delay based on the number and priority of received indicators, allowing them to minimize delays while still avoiding collisions in critical cases.
Solution Approach 2:
The system changes the parameter of transmission timing dynamically based on received preferred transmission indicators. Instead of fixed random selection or uniform delay, devices adjust their transmission timing parameters adaptively - delaying by different amounts based on buffer size, indicator priority, and network conditions to balance collision avoidance with delay minimization.
Data Source
AI summary
In a communication system having a plurality of user equipment (UE) devices that are operating in a contention based mode for device-to-device (D2D) communication, each UE device transmits a preferred transmission indicator when a condition for preferred transmission is met at the UE device. If a UE device receives a preferred transmission indicator, the UE device delays transmission of a D2D scheduling assignment (SA) to contend for communication resources for D2D communication. The length of the delay can be based on a number of preferred transmission indicators that are received. The preferred transmission indicator is based on a buffer size in one example.