Scheduling Assignment Retransmission for D2D Power Savings
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Solution Overview
Problem
In device-to-device (D2D) communications, existing technologies face challenges in power savings and interference mitigation, particularly in wireless multiple-access systems where mobile devices experience battery drain and interference from base stations and other devices.
Innovation Solution
The implementation of a scheduling assignment (SA) transmission system that includes retransmitting SA information using a predetermined retransmission pattern, providing time or frequency diversity, and indicating resources for data transmissions, allowing devices to monitor only scheduled periods and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If devices continuously monitor for transmissions to ensure reliable reception, then reception reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring where devices monitor for SA transmissions only during specific subframes indicated by the SA message, rather than continuously. The monitoring periodicity is determined based on the SA retransmission pattern, allowing devices to enter low-power states between monitoring intervals while still reliably receiving SAs through the periodic retransmissions.
2Reliability
If SA is transmitted multiple times to ensure reliable reception, then reception reliability is improved, but interference from multiple transmissions increases
Solution Approach 1:
The patent determines the SA retransmission pattern before actual transmissions occur. The pattern includes parameters such as the number of retransmissions, time offsets, and frequency offsets, which are predetermined and communicated to devices. This allows devices to anticipate and prepare for retransmissions at specific times and frequencies, reducing the need for continuous monitoring and thereby reducing overall interference while maintaining reliability.
Data Source
AI summary
Methods, systems, and devices are described for transmissions and retransmissions of scheduling assignment (SA) information, and for content of SA transmissions. SAs may be transmitted during an initial communications period, followed by data transmissions for a certain time period. A device may monitor for transmissions during the SA period and then monitor for data transmissions during periods indicated in a received SA. SAs may be retransmitted according to a retransmission pattern that may provide time or frequency diversity patterns in order to enhance reception of SAs at a receiving device. Retransmission patterns may be determined based on a resource from an SA resource pool that is used for an initial transmission of the SA.