Uplink Control Using Downlink Quality in Asymmetric Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems using carrier aggregation, accurately assessing and controlling uplink transmission quality is challenging when there are no corresponding downlink components, leading to issues like useless transmission and inflexible handover control.
Innovation Solution
The system allocates downlink and uplink sub-bands in multiple frequency bands, with the communication terminal measuring downlink quality and the base station determining uplink control based on this, and in cases where only uplink sub-bands exist, measuring a monitor downlink quality to assess and control the uplink sub-band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with more uplink component carriers than downlink component carriers, then uplink communication capacity is improved, but accurate quality assessment and control of uplink transmission becomes difficult
Solution Approach 1:
The patent introduces a downlink component carrier as an intermediary reference for assessing uplink quality. When a uplink component carrier lacks a paired downlink component carrier, the system uses a downlink component carrier from the same frequency band as a substitute reference to measure path loss and assess transmission quality, enabling accurate control without direct uplink-downlink pairing.
Solution Approach 2:
The patent changes the reference parameter selection dynamically based on the presence or absence of paired component carriers. When a uplink component carrier has no corresponding downlink component carrier, the system switches to using a downlink component carrier with matching frequency band characteristics, adapting the assessment parameters to maintain accuracy despite the asymmetric carrier configuration.
2Adaptability or versatility
If uplink and downlink component carriers are in different frequency bands, then frequency flexibility is improved, but path loss measurement accuracy deteriorates
Solution Approach 1:
The patent applies local quality by selecting downlink component carriers that match the frequency band characteristics of the uplink component carrier being assessed. Instead of using a universal reference, the system chooses a reference specific to the local frequency band context, ensuring that path loss measurements reflect the actual propagation conditions of that band.
3Ease of operation
If downlink component carriers are used for uplink transmission control, then control flexibility is improved, but useless transmission occurs when downlink quality does not reflect uplink conditions
Solution Approach 1:
The patent dynamically changes the reference parameter selection based on frequency band matching. When controlling uplink transmission, the system selects a downlink component carrier whose frequency band matches the uplink component carrier's band, ensuring that the quality parameters used for control decisions accurately reflect the actual uplink transmission conditions.
Data Source
AI summary
According to a control method of a wireless communication system in which wireless communication between a base station (12) and a communication terminal (11) is carried out by use of a plurality of discontinuous frequency bands, in a case where an onlyUL-CC having no existing corresponding DL-CC is present (S21), a communication quality of a DL-CC in a frequency band including the onlyUL-CC is measured as a communication quality of a DL-CC corresponding to the onlyUL-CC (S22) for the purpose of accurate control of the onlyUL-CC.