PDCCH Status Indication for NB-IoT Uplink Efficiency
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Solution Overview
Problem
In NB-IoT systems, the existing methods for status indication in uplink data transmission lead to low transmission efficiency and high power consumption due to unnecessary RLC status reports and prolonged monitoring of PDCCHs, even after successful data transmission.
Innovation Solution
The proposed solution involves using PDCCH information to indicate successful receipt of uplink data and permit the UE to enter a DRX status, reducing the need for RLC status reports and enabling faster entry into a power-saving DRX mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RLC status reports are transmitted to indicate successful receipt of uplink data, then transmission reliability is improved, but transmission efficiency deteriorates due to additional signaling overhead
Solution Approach 1:
The patent extracts the status indication function from the RLC layer and relocates it to the MAC layer through the PDCCH. Instead of transmitting separate RLC status reports, the base station uses the PDCCH to carry uplink data reception status information, thereby eliminating redundant signaling while maintaining reliable status indication.
Solution Approach 2:
The PDCCH, traditionally used for scheduling control, is enhanced to serve multiple functions: it simultaneously carries scheduling information and uplink data reception status indication. This multi-functionality reduces the need for separate status report messages, improving transmission efficiency without compromising reliability.
2Reliability
If UE continues to monitor PDCCH after successful uplink data transmission, then transmission reliability is improved, but power consumption increases
Solution Approach 1:
The base station provides explicit feedback to the UE through the PDCCH regarding the successful reception of uplink data. Upon receiving this feedback, the UE can confidently stop monitoring the PDCCH and transition to DRX mode, ensuring that no critical information is missed while enabling power savings.
Solution Approach 2:
The UE's PDCCH monitoring behavior transitions from a static continuous monitoring mode to a dynamic mode where monitoring is adjusted based on received feedback. This dynamic adjustment allows the UE to switch from active monitoring to DRX mode appropriately, balancing reliability and power consumption.
3Use of energy by moving object
If UE enters DRX status immediately after uplink data transmission, then power consumption is reduced, but transmission reliability deteriorates due to missed status feedback
Solution Approach 1:
The base station sends the uplink data reception status indication to the UE before the UE would otherwise need to remain in active monitoring mode. This preliminary action provides the UE with sufficient information to confidently enter DRX mode without risking missed feedback, as the status information is already delivered.
4Measurement precision
If RLC status reports are transmitted for every uplink data transmission, then measurement precision of transmission status is improved, but loss of time increases due to additional signaling delays
Solution Approach 1:
The patent merges the status indication function with the existing PDCCH scheduling information. By combining these functions into a single signaling mechanism, the system eliminates the time delay associated with separate status report transmissions while maintaining precise transmission status information through the integrated PDCCH messages.
Data Source
AI summary
A transmission apparatus and method of status indication and a communication system. The transmission method of status indication includes: determining whether an RLC layer has successfully received all RLC PDUs of uplink data when a base station receives the uplink data transmitted by a UE; and transmitting PDCCH information to the UE, in a case where the RLC layer has successfully received all the RLC PDUs of the uplink data; the PDCCH information is used to indicate that the uplink data have been successfully received and/or the UE is permitted to enter into a DRX status. Hence, not only transmission of RLC status report may be reduced and transmission efficiency of the whole system may be improved, but also the UE may be made to enter into the DRX status as fast as possible and power consumption of the UE may be lowered.