EPDCCH Stand-Alone Operation via Enhanced Common Search Space
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Solution Overview
Problem
The 3GPP LTE Release 11 system lacks support for stand-alone operation of the enhanced physical downlink control channel (EPDCCH), particularly in cases where a new carrier type operates independently without a legacy carrier, as there is no defined enhanced common search space (ECSS) for scheduling common control messages without RRC or higher layer signaling.
Innovation Solution
The method involves defining an enhanced common search space (ECSS) within the EPDCCH, with scheduling information obtained by decoding candidate control channels, and using predefined rules or signaling in the physical broadcast channel (PBCH) and enhanced physical control format indication channel (EPCFICH) to determine the location and configuration of the common EPDCCH set, enabling stand-alone operation of the EPDCCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy PDCCH is used for control signaling, then backward compatibility is maintained, but stand-alone operation of new carrier type is not supported
Solution Approach 1:
The control channel is segmented into two distinct types: legacy PDCCH for backward compatibility and new EPDCCH for enhanced functionality. The EPDCCH is further divided into common search space (ECSS) and UE-specific search space (EUSS), allowing independent operation on new carrier types while maintaining separation of concerns between common and dedicated control signaling.
Solution Approach 2:
The common search space functionality is extracted from the legacy PDCCH framework and implemented as a separate enhanced common search space (ECSS) within the EPDCCH structure. This extraction enables stand-alone operation on new carrier types by providing common control signaling capabilities independent of legacy PDCCH.
2Productivity
If EPDCCH is configured without ECSS, then UE-specific scheduling is improved, but common control message scheduling fails
Solution Approach 1:
The patent merges the functionality of legacy common search space with UE-specific search space into a unified EPDCCH framework. The ECSS and EUSS are combined in the same physical resource blocks but operate with different monitoring configurations, allowing both common control messages and UE-specific scheduling to coexist and improve overall scheduling efficiency.
Solution Approach 2:
The EPDCCH structure is designed to be universal, supporting both common control signaling (ECSS) and UE-specific scheduling (EUSS) within the same physical channel framework. This multi-functionality allows a single control channel structure to serve multiple purposes: system information broadcasting, paging, random access response, and dedicated data scheduling.
3Adaptability or versatility
If RRC signaling is used for ECSS configuration, then flexibility is improved, but operation without higher layer signaling is not possible
Solution Approach 1:
The ECSS configuration parameters are predetermined and pre-configured in the system, allowing the common search space to be established before RRC connection is formed. This preliminary configuration enables stand-alone operation on new carrier types where the UE can acquire common control information without requiring higher layer signaling first.
Data Source
AI summary
A method for obtaining scheduling information of a data channel is disclosed. The method includes: receiving a set of radio resources for a set of candidate control channels, wherein a part of the set of candidate control channels constitute the enhanced common search space (ECSS) for an enhanced physical downlink control channel (EPDCCH); attempting to decode each candidate control channel to obtain a physical control channel; and obtaining scheduling information of the data channel from the decoded physical control channel.