User Equipment HARQ Response Control for D2D QoS
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Solution Overview
Problem
Conventional D2D communication systems do not support Hybrid Automatic Repeat Request (HARQ) processing, which is essential for managing Quality of Service (QoS) in inter-terminal direct communication.
Innovation Solution
A user equipment is configured with a receiving unit to receive signals and information for HARQ response resources, a control unit to determine HARQ responses based on reception results, and a transmitting unit to transmit these responses using the appropriate resources, enabling appropriate re-transmission control in inter-terminal direct communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ processing is implemented in D2D communication, then re-transmission control and QoS management are improved, but device complexity and protocol overhead increase
Solution Approach 1:
The base station apparatus serves as an intermediary that manages HARQ processing for D2D communication. The base station transmits downlink data to the first user equipment, which then forwards it to the second user equipment via D2D. The base station also receives HARQ responses from the second user equipment and coordinates re-transmissions, thereby implementing HARQ control without requiring complex peer-to-peer HARQ management between user equipments.
Solution Approach 2:
The system implements feedback mechanisms where the second user equipment sends HARQ responses (ACK/NACK) to the base station, which then uses this feedback to determine whether re-transmission is needed. This feedback loop enables reliable QoS management and re-transmission control while keeping the complexity manageable through centralized base station coordination.
2Reliability
If HARQ response transmission is enabled in D2D, then communication reliability improves, but uplink resource consumption increases
Solution Approach 1:
The base station acts as an intermediary that collects HARQ responses from the second user equipment. Instead of requiring direct HARQ feedback between user equipments (which would consume additional D2D resources), the base station receives the feedback on uplink resources it already manages, thereby controlling resource consumption through centralized scheduling.
Solution Approach 2:
The uplink resources already allocated for user equipment to communicate with the base station are multi-used for HARQ feedback transmission. The same uplink channels and resources that support regular uplink communication are also utilized for HARQ response transmission, avoiding the need for dedicated HARQ feedback resources and reducing overall resource consumption.
Data Source
AI summary
A user equipment includes a receiving unit configured to receive a first signal of inter-terminal direct communication transmitted from a first user equipment, and information indicating a first resource for transmitting a HARQ (Hybrid Automatic Repeat Request) response corresponding to the first signal of inter-terminal direct communication transmitted from either one of a base station apparatus or the first user equipment; a control unit configured to determine the HARQ response based on a reception result of the first signal of inter-terminal direct communication; and a transmitting snit configured to transmit the determined HARQ response to the base station apparatus or the first user equipment, by using the first resource for transmitting the HARQ response.