D2D Retransmission Coordination via Base Station Mediator
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Solution Overview
Problem
In device-to-device (D2D) communication systems using wireless LAN, simultaneous retransmission operations among multiple mobile stations are unstable and prone to delay due to asymmetric channel conditions and inefficient resource allocation, particularly when feedback information is directly transmitted without a base station's involvement.
Innovation Solution
A method and apparatus for performing retransmission operations in D2D communication systems, where feedback information is used to determine the need for retransmitting data, with options to transmit through a base station or directly between mobile stations, utilizing hybrid automatic repeat request (HARQ) and automatic repeat request (ARQ) schemes, and allocating resources effectively to prevent delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple mobile stations perform simultaneous retransmission operations using direct feedback transmission in D2D communication, then communication efficiency is improved, but system stability deteriorates due to asymmetric channel conditions and resource allocation conflicts
Solution Approach 1:
The patent introduces a base station as an intermediary to manage and coordinate retransmission operations among multiple mobile stations. The base station receives feedback information from receiving MSs, determines retransmission scheduling, and allocates resources appropriately, thereby maintaining system stability while enabling efficient simultaneous retransmissions.
Solution Approach 2:
The patent implements dynamic resource allocation where the base station adjusts resource assignment based on real-time channel conditions and feedback information. The retransmission scheduling is dynamically determined by the base station considering the asymmetric channel situations between different MS pairs, allowing the system to adapt to changing conditions while maintaining stability.
2Adaptability or versatility
If feedback information is transmitted directly between mobile stations without base station involvement, then resource allocation flexibility is improved, but retransmission delay increases due to lack of coordinated resource management
Solution Approach 1:
The base station serves as a mediator that receives feedback information from mobile stations and coordinates retransmission resource allocation. This approach maintains the flexibility of direct feedback transmission while preventing delays through centralized resource management and scheduling decisions.
Solution Approach 2:
The base station performs preliminary resource allocation and scheduling decisions based on received feedback information before actual retransmission occurs. By determining resource assignment in advance based on feedback, the system avoids last-minute conflicts and reduces retransmission delay while maintaining allocation flexibility.
3Device complexity
If resource allocation is restricted to one transmitting MS and one receiving MS at a time, then resource allocation simplicity is improved, but overall system throughput deteriorates due to inability to support simultaneous retransmissions
Solution Approach 1:
The base station acts as a central coordinator that manages resource allocation for multiple simultaneous retransmission operations. It receives feedback from multiple receiving MSs, determines appropriate resource assignments for each transmitting MS, and allocates resources to prevent conflicts, thereby enabling simultaneous retransmissions while maintaining controlled complexity through centralized management.
Solution Approach 2:
The patent segments the resource allocation process into distinct phases: feedback collection from receiving MSs, centralized scheduling decision by the base station, and resource assignment to transmitting MSs. This segmentation allows the system to handle multiple simultaneous retransmissions by dividing the complex allocation task into manageable steps, improving throughput while controlling complexity.
Data Source
AI summary
A method for performing by a mobile station (MS) a retransmission operation in a device to device (D2D) communication system is provided. The method includes performing a data communication with a peer MS using a D2D communication, receiving feedback information for a retransmission operation for data which is transmitted to the peer MS which is transmitted using a resource block mapped to identification information of a D2D connection from the peer MS, determining whether there is need for retransmission of the data based on the feedback information received from the peer MS, and if there is need for the retransmission of the data, retransmitting the data to the peer MS.