Shared PDCCH Region for Carrier Aggregation Control
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Solution Overview
Problem
In LTE networks, carrier aggregation for data transmission requires substantial resource allocation for separate control channels on each carrier, which can be inefficient and difficult to implement due to varying interference levels, especially when one carrier experiences high interference, making it challenging to maintain a PDCCH region.
Innovation Solution
The system allows sharing of a single Physical Downlink Control Channel (PDCCH) region among multiple carriers, enabling DCI control messages distributed via one PDCCH region to determine resource allocations on each carrier, without modifying existing DCI control message formats, by assigning CCEs into groups specific to each carrier and using carrier indices to differentiate allocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate control channels are allocated for each carrier in carrier aggregation, then each carrier can have dedicated control resources, but resource allocation becomes inefficient and complex especially when interference levels vary
Solution Approach 1:
The patent merges control channels from multiple carriers into a single shared PDCCH region. Instead of maintaining separate PDCCH regions for each carrier, the invention combines them into one unified control channel that serves multiple carriers, thereby reducing overall resource allocation while maintaining control reliability.
Solution Approach 2:
The shared PDCCH region is designed to serve multiple carriers simultaneously, making it a universal control channel. The control channel can dynamically allocate resources across different carriers based on their specific needs and interference conditions, eliminating the need for dedicated control channels for each carrier.
2Reliability
If a PDCCH region is maintained on each carrier, then control messages can be transmitted reliably, but resource overhead increases significantly
Solution Approach 1:
The patent combines PDCCH regions from multiple carriers into a single shared PDCCH region, reducing the total quantity of control channel resources required. This merging approach maintains transmission reliability by ensuring adequate control resources are available in the shared region without duplicating control channels across carriers.
3Adaptability or versatility
If separate PDCCH regions are used for each carrier, then carrier-specific control can be implemented, but implementation becomes difficult when one carrier experiences high interference
Solution Approach 1:
The shared PDCCH region provides universal control capability that can adapt to different carrier conditions. The control channel can dynamically adjust resource allocation and modulation schemes based on the specific interference conditions of each carrier, maintaining adaptability while simplifying implementation through a unified control structure.
4Reliability
If multiple separate control channels are allocated for carrier aggregation, then each carrier receives adequate control resources, but bandwidth efficiency decreases
Solution Approach 1:
The patent merges control resources from multiple carriers into a shared PDCCH region, reducing the total bandwidth consumed by control channels. This consolidation ensures adequate control resources are available while improving bandwidth efficiency by eliminating redundant control channel allocations across carriers.
Data Source
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AI summary
A method for processing a control channel at a user agent (UA) to identify at least one of an uplink and a downlink resource allocated by a resource grant within a multi-carrier communication system wherein resource grants are specified by control channel element (CCE) subset candidates, the method comprising the steps of identifying the number of configured carriers used to communicate with the access device, based on the number of configured carriers used to communicate with the access device, identifying a number of CCE subset candidates to decode and decoding up to the identified number of CCE subset candidates in an attempt to identify the resource grant.