LTE Carrier Aggregation PDCCH Resource Allocation
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Solution Overview
Problem
In LTE communication systems, especially during Carrier Aggregation (CA), the limited resource availability for transmitting PDCCH (UL grant) can lead to incomplete distribution across multiple DL carriers, resulting in resource shortages when the number of DL carriers exceeds the number of UL carriers.
Innovation Solution
A mobile communication method where the radio base station individually notifies mobile stations of the correspondence relation between DL carriers for transmitting uplink assignment signals and UL carriers assigned with uplink resources, allowing for the distribution of PDCCH (UL grant) across multiple DL carriers, enabling efficient resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple DL carriers are used in Carrier Aggregation, then peak throughput and frequency use efficiency are improved, but PDCCH (UL grant) resource shortage occurs when the number of DL carriers exceeds the number of UL carriers
Solution Approach 1:
The patent segments the PDCCH resource allocation by introducing a one-to-one correspondence between DL carriers and UL carriers for PDCCH transmission. Each DL carrier is paired with a specific UL carrier to transmit PDCCH, dividing the limited PDCCH resources across multiple DL carriers. This segmentation allows the system to support more DL carriers than UL carriers while maintaining adequate PDCCH resources for uplink scheduling.
2Adaptability or versatility
If the number of DL carriers is increased beyond the number of UL carriers, then frequency use efficiency is improved, but resource distribution of PDCCH becomes incomplete
Solution Approach 1:
The patent applies universality by enabling each UL carrier to serve dual functions: (1) as the uplink data carrier for user traffic, and (2) as the dedicated PDCCH carrier for transmitting uplink grants related to that UL carrier. This multi-functionality ensures that even when DL carriers outnumber UL carriers, each UL carrier can reliably handle PDCCH resources for its paired DL carrier, achieving complete and reliable resource distribution across all DL carriers.
Data Source
AI summary
A mobile communication method according to the present invention comprises: a step A of individually notifying, by a radio base station eNB, a mobile station UE performing CA of correspondence relation between a DL carrier for transmitting an “UL grant” and an UL carrier to which a PUSCH resource is assigned by the “UL grant”, and a step B of transmitting, by the mobile station UE, an uplink data signal using the PUSCH resource through the UL carrier based on the above-described correspondence relation when the “UL grant” is received through the DL carrier.