Uplink Grant PDCCH CCE and Power Adaptation
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Solution Overview
Problem
Current LTE systems face challenges in reliably transmitting the Physical Downlink Control Channel (PDCCH) due to differences in transmission modes and inter-cell interference between control and data areas, making it difficult to ensure an error rate less than 1% using wideband Channel Quality Indicators (CQI) for link adaptation.
Innovation Solution
The method involves adjusting the number of Control Channel Elements (CCEs) and transmission power of the uplink grant PDCCH based on successful reception of the Physical Uplink Shared Channel (PUSCH) by the UE, using SINR modifications and RSSI threshold comparisons to optimize CCE allocation and power adjustment dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wideband CQI is used for PDCCH link adaptation, then the method is simple, but the reliability of PDCCH transmission cannot be ensured (error rate > 1%)
Solution Approach 1:
The patent implements a feedback mechanism where the base station monitors PUSCH reception status and sends adjustment indications to the UE. The UE feeds back CQI information based on this adjustment, creating a closed-loop system that continuously optimizes PDCCH transmission parameters to maintain error rate < 1% while adapting to changing channel conditions
Solution Approach 2:
The patent performs preliminary actions by adjusting the PDCCH transmission point (transmission power or CCE allocation) before actual PDCCH transmission based on predicted channel conditions from PUSCH reception status. This proactive adjustment ensures reliable PDCCH transmission before errors can occur
2Reliability
If the number of CCEs is increased to ensure PDCCH reliability, then transmission reliability improves, but resource efficiency deteriorates
Solution Approach 1:
The patent dynamically adjusts the number of CCEs allocated to PDCCH based on real-time PUSCH reception status and channel conditions. When channel conditions are good, fewer CCEs are used; when conditions deteriorate, more CCEs are allocated. This dynamic adaptation ensures PDCCH reliability > 99% while maximizing resource utilization efficiency by avoiding excessive CCE allocation during good conditions
3Reliability
If transmission power is increased to reduce PDCCH error rate, then transmission reliability improves, but power consumption increases
Solution Approach 1:
The patent changes transmission parameters (power level or CCE allocation) based on PUSCH reception status monitoring. When PUSCH reception is successful, the system infers good channel conditions and uses lower PDCCH power or fewer CCEs. When PUSCH reception fails, the system increases PDCCH power or CCE allocation to ensure reliability < 1% error rate, thereby optimizing power consumption while maintaining reliability
Data Source
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AI summary
The disclosure provides a method and a base station for adjusting an uplink grant physical downlink control channel of a UE adaptively. The method includes: receiving a physical uplink shared channel transmitted on an uplink resource indicated by a current uplink grant physical downlink control channel from the UE; judging whether or not the UE has received the uplink grant physical downlink control channel successfully in accordance with the received physical uplink shared channel; and determining the number of control channel elements CCEs occupied by the uplink grant physical downlink control channel and/or a transmission power of the uplink grant physical downlink control channel in accordance with the judgment result.