Frequency Hopping Signal Retransmission for D2D Interference
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Solution Overview
Problem
In device-to-device (D2D) communication systems, existing methods for resource selection during repeated signal transmission lead to resource collisions among multiple UEs, increasing complexity and power consumption for the receiver UE, as they struggle to decode and combine discovery signals from unknown resource locations.
Innovation Solution
A method where a first UE determines a resource for retransmitting a signal based on the initially used resource and a frequency hopping pattern, reducing interference and simplifying blind detection for the receiver UE by using a predetermined frequency hopping pattern, either cell-specific or UE-specific, to stagger resource usage across UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If resources are randomly selected for each repeated transmission of discovery signals, then interference between multiple UEs is randomized, but receiver complexity and power consumption increase significantly due to blind detection across multiple possible resource positions
Solution Approach 1:
The transmitter UE performs preliminary action by determining the resource position for repeated discovery signal transmissions in advance, using a predetermined frequency hopping pattern based on the initial resource position. This allows the receiver UE to calculate the same resource positions without blind detection, significantly reducing receiver complexity while maintaining interference randomization through the frequency hopping mechanism.
2Ease of operation
If subsequent repeated transmission resources are determined only by the first portion of resources, then resource selection is simplified, but resource collision occurs among multiple D2D transmitter UEs reducing discovery signal reliability
Solution Approach 1:
The patent introduces dynamic frequency hopping patterns for resource determination. Instead of static resource allocation, the resource position for repeated transmissions dynamically changes according to a frequency hopping pattern that depends on the initial resource position, subframe index, and other parameters. This dynamic approach maintains simplicity while avoiding collisions through frequency diversity.
3Ease of manufacture
If multiple D2D transmitter UEs randomly select the same initial resources, then resource selection process is simple, but resource collision occurs in subsequently repeatedly transmitted messages
Solution Approach 1:
The patent resolves resource collisions by introducing frequency domain diversity through frequency hopping. While UEs may select the same initial time-domain resources, the frequency hopping pattern shifts the resource position in the frequency domain across different subframes, effectively utilizing another dimension (frequency) to avoid collisions and maintain simple initial resource selection.
Data Source
AI summary
Embodiments of the present disclosure provide a signal retransmission apparatus and method and a communication system. The method includes: a first UE determines a resource for retransmitting a signal according to a resource for initially transmitting the signal and a frequency hopping pattern; and retransmits the signal to a second UE according to the determined resource. With the embodiments of the present disclosure, interference between UEs may be randomized as possible, and complexity of blind detection by receiver end UE may be lowered as possible.