e-PDCCH Search Space Design for Wireless Control Capacity
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing the search space for the physical downlink control channel (PDCCH) in heterogeneous networks, particularly with the introduction of enhanced PDCCH (e-PDCCH) which requires improved control channel capacity and frequency-domain Inter Cell Interference Coordination, especially in scenarios involving new carrier types and heterogeneous networks.
Innovation Solution
The implementation of an enhanced physical downlink control channel (e-PDCCH) with advanced search space design, including the use of enhanced PHICH and pseudo-random mapping functions, allows for increased control channel capacity, improved spatial reuse, and support for new carrier types, while maintaining compatibility with legacy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If e-PDCCH is introduced to increase control channel capacity, then control channel capacity is improved, but device complexity increases
Solution Approach 1:
The search space for e-PDCCH is segmented into multiple candidate positions within the physical resource blocks. Instead of a single centralized control region, the control channel candidates are distributed across multiple locations, allowing the system to increase control channel capacity while managing device complexity through structured segmentation of the search space.
2Quantity of substance
If search space is expanded to support more e-PDCCH candidates, then control channel capacity increases, but blind decoding complexity increases
Solution Approach 1:
The patent establishes predetermined rules and configurations for search space candidates, including fixed physical resource block assignments and predefined candidate positions. By performing preliminary configuration of the search space structure, the system allows UEs to efficiently perform blind decoding without having to explore all possible positions, thus increasing control channel capacity while managing decoding complexity through pre-planned search patterns.
3Object-affected harmful factors
If e-PDCCH uses distributed resource allocation for frequency-domain ICIC, then inter-cell interference is mitigated, but device complexity increases
Solution Approach 1:
The patent implements frequency-domain Inter Cell Interference Coordination by allocating e-PDCCH candidates to specific physical resource blocks with particular properties. Different cells can use different frequency resources for their e-PDCCH transmissions, creating local quality differences in resource allocation that mitigate inter-cell interference while maintaining manageable device complexity through structured resource assignment rules.
Data Source
AI summary
An enhanced physical downlink control channel (e-PDCCH) may provide carrier aggregation (CA) enhancements, help support new carriers which may not be backwards compatible, reduce control channel capacity limitations of coordinated multipoint (CoMP) transmissions, and enhance DL MIMO. In wireless communication networks, such as Long Term Evolution (LTE), user equipments (UEs) may monitor both a common search space and a UE-specific search space in a control region. A search space may comprise a set of channel control element (CCE) locations where a UE may find its PDCCHs. One or more CCEs are used to transmit each PDCCH. Certain aspects provide methods and apparatus for determining a search space comprising a subset of CCEs located on a band edge of available frequency resources, and performing a search of the search space to decode at least one PDCCH.