Base Station Search Space Configuration for LTE-A CCE Allocation
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Solution Overview
Problem
When asymmetric component bands are used between uplink and downlink in LTE-A systems, securing PUCCH resources for ACK/NACK signals from multiple downlink component bands leads to resource inefficiency, reducing the available resources for uplink data transmission and limiting CCE allocation flexibility, resulting in decreased data throughput.
Innovation Solution
The base station and terminal implement a method to set different search spaces for downlink component bands, allowing flexible CCE allocation without ACK/NACK signal collisions by associating PUCCH resources with CCEs in a way that PUCCHs are shared between multiple downlink component bands, and mapping ACK/NACK signals to uplink control channels associated with allocated CCEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PUCCH resources are secured for ACK/NACK signals from multiple downlink component bands, then reliability of downlink acknowledgment is improved, but uplink data transmission resources are reduced
Solution Approach 1:
A single uplink component band is used to carry ACK/NACK signals for multiple downlink component bands. The PUCCH resources in this single uplink component band are configured to respond to downlink data from multiple downlink component bands, making the uplink control channel universal across multiple downlink carriers.
Solution Approach 2:
Multiple downlink component bands are merged into a single uplink component band for acknowledgment purposes. Instead of having separate PUCCH resources for each downlink component band, the patent combines the acknowledgment function into one shared uplink component band, reducing overall resource consumption.
2Reliability
If PUCCH resources are secured for each downlink component band, then acknowledgment coverage is improved, but control channel resource consumption increases
Solution Approach 1:
The PUCCH resources in the single uplink component band are designed to serve multiple downlink component bands universally. This multi-functional configuration allows the same control channel resources to handle acknowledgments for data received from different downlink carriers.
Solution Approach 2:
The patent merges the control channel resources for multiple downlink component bands into a single shared uplink component band. This consolidation reduces the total quantity of control channel resources needed while maintaining comprehensive acknowledgment coverage.
3Reliability
If CCE allocation is restricted to avoid ACK/NACK collisions, then signal collision reliability is improved, but CCE allocation flexibility is reduced
Solution Approach 1:
The patent resolves the collision issue by transitioning from a one-to-one mapping (one PUCCH per downlink component band) to a many-to-one mapping (multiple PUCCHs from multiple downlink component bands mapping to a single uplink component band). This dimensional change in resource mapping eliminates the need for restrictive CCE allocation while avoiding collisions through proper resource configuration.
Data Source
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AI summary
Disclosed is wireless communication base station equipment in which CCE allocation can be flexibly performed without collision of ACK/NACK signals between a plurality of unit bands, even when wideband transmission is performed exclusively on a downlink circuit. In this equipment, an allocation unit (105) sets up mutually different search spaces for each of a plurality of downlink unit bands, with respect to wireless communication terminal devices that communicate using a plurality of downlink unit bands, and allocates resource allocation information of downlink circuit data destined for the wireless communication terminal devices to CCEs in mutually different search spaces for each of the plurality of downlink unit bands, and an ACK/NACK reception unit (119); extracts a response signal in respect of the downlink circuit data from the uplink control channel associated with the CCE to which the resource allocation information of this downlink circuit data was allocated.