HARQ Buffer Management for 5G NR Uplink Grants
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Solution Overview
Problem
In wireless networks, especially in 5G-NR technology, user devices often transmit unnecessary data from HARQ buffers due to misinterpretation of uplink grants, leading to power consumption and interference, as they ignore initial grants and fail to transmit data, causing base stations to request retransmissions even when no data was sent.
Innovation Solution
Implementing HARQ buffer management techniques where user devices remove data from the buffer if no data is transmitted during an uplink grant, thereby ignoring subsequent retransmission requests from the base station, thus preventing unnecessary data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the user device ignores the initial uplink grant and does not transmit data, then the device can avoid transmitting unnecessary data from the HARQ buffer, but the base station may incorrectly request retransmission causing the device to consume power and create interference
Solution Approach 1:
The user device performs a preliminary check of the HARQ buffer status before transmitting data in response to an uplink grant. If the buffer is determined to be empty, the device proactively sends a buffer status report (BSR) to the base station before the scheduled transmission time. This preliminary action prevents the base station from mistakenly requesting retransmission of non-existent data, thereby avoiding unnecessary power consumption and interference while maintaining communication reliability.
2Ease of operation
If the user device transmits data from the HARQ buffer in response to a retransmission request, then the device follows the base station's instruction, but the transmission becomes unnecessary and consumes power
Solution Approach 1:
The user device implements a feedback mechanism where it continuously monitors its HARQ buffer status and compares it with received uplink grants and retransmission requests. When the device determines that the buffer is empty despite receiving a retransmission request, it sends a negative acknowledgment (NACK) or a specific BSR indicating empty buffer status. This feedback loop allows the device to comply with protocol requirements while preventing unnecessary transmissions and power consumption.
3Ease of operation
If the user device transmits unnecessary data from the HARQ buffer, then the device responds to the retransmission request, but the transmission causes interference with other wireless communications
Solution Approach 1:
The user device performs a preliminary verification of buffer contents before transmitting data in response to any uplink grant or retransmission request. By checking whether the HARQ buffer actually contains data that needs retransmission, the device avoids sending unnecessary signals that would cause interference. This preliminary action ensures protocol compliance while eliminating harmful interference effects.
Data Source
AI summary
This document describes techniques for, and systems that enable, HARQ buffer management. These techniques include removing (314), based on a user device failing to transmit data during an uplink grant, data stored in a HARQ buffer. By removing the data stored in the HARQ buffer, the user device can avoid (322) transmitting, to the base station, the data stored in the HARQ buffer in response to a retransmission request from the base station.