Device-to-Device Communication HARQ Feedback Sliding Window
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing direct mobile communications (DMC) between user equipment (UEs) without involving a communications controller, leading to unnecessary costs and overhead, while also needing to offload traffic from base stations and enable proximity-based services.
Innovation Solution
A system and method that allow UEs to communicate directly through a network-centric approach, where a communications controller allocates time and frequency resources for DMC groups, ensuring efficient HARQ timing and ACK/NACK feedback, and uses a new HARQ protocol to manage data transmission and reception within DMC links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a communications controller is involved in every DMC communication path to manage resources, then resource allocation and HARQ management are reliable, but communication overhead and operational costs increase
Solution Approach 1:
The patent segments the communication system into two distinct parts: a network-controlled portion for resource allocation and a device-autonomous portion for actual data transmission and HARQ management. The eNB allocates radio resources and provides configuration parameters, but the DMC UEs independently manage their direct communication links, including HARQ processes and acknowledgments, without requiring continuous controller involvement in each transmission.
Solution Approach 2:
The communications controller performs preliminary resource allocation and configuration before DMC communications begin. The eNB assigns radio resources, configures HARQ parameters, and provides uplink/downlink timing relationships in advance. This preliminary setup enables the DMC UEs to autonomously manage their direct communications without requiring real-time controller intervention, reducing overhead while maintaining reliability.
2Reliability
If base stations handle all DMC traffic to ensure quality of service, then service quality is maintained, but base station workload and network costs increase
Solution Approach 1:
The patent extracts the data transmission function from the base station and relocates it to the DMC UEs themselves. While the eNB maintains control over resource allocation and configuration, the actual data packets are transmitted directly between DMC UEs over the air interface without passing through the base station. This extraction reduces base station workload and enables traffic offloading while maintaining network oversight for quality of service.
Solution Approach 2:
The patent introduces a hybrid architecture where the base station acts as an intermediary for control signaling rather than data forwarding. The eNB mediates resource allocation, HARQ configuration, and uplink/downlink coordination, but allows direct peer-to-peer data transmission between DMC UEs. This intermediary role maintains service quality through network control while enabling productivity gains through direct device communication.
3Device complexity
If DMC operates completely autonomously without network control to reduce overhead, then operational costs decrease, but coordination and resource management become difficult
Solution Approach 1:
The communications controller performs preliminary resource allocation and configuration before DMC communications begin. The eNB assigns radio resources, configures HARQ parameters, and provides uplink/downlink timing relationships in advance. This preliminary setup enables the DMC UEs to autonomously manage their direct communications without requiring real-time controller intervention, reducing overhead while maintaining reliability.
Solution Approach 2:
The patent implements feedback mechanisms where DMC UEs report their communication status, channel conditions, and HARQ acknowledgments back to the eNB. This feedback enables the network to monitor and coordinate resources effectively, adjust allocations dynamically, and maintain overall system coordination while allowing autonomous operation at the device level.
Data Source
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AI summary
An embodiment of a system for operating a communications controller for a group of user equipments engaged in a direct mobile communication ("DMC") link in a wireless communications system is provided. The communications controller is configured to allocate a set of subframes to the group of UEs for the DMC link, signal the set of allocated subframes to the group of UEs, and signal a length of a sliding window to the group of UEs. In an embodiment, ACK/NACK feedback for communications over the DMC link is aggregated according to the length of the sliding window, and the ACK/NACK feedback for the communications over the DMC link is determined independently from ACK/NACK feedback for cellular transmission between the communication controller and the group of UEs. In an embodiment, the length of the sliding window is a number of subframes.