DMRS Resource Allocation for Enhanced Control Channel
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently allocating DeModulation Reference Signal (DMRS) resources and implicitly indicating DMRS configurations for Enhanced Control Channel (E-CCH) transmission, particularly in scenarios where multiple E-CCHs are multiplexed in one Resource Block (RB).
Innovation Solution
The system allocates DMRS resources based on the number of E-CCHs scheduled in an RB, configuring either four or two DMRS ports depending on the aggregation level, and performs rate matching or puncturing around DMRS Resource Elements (REs) to efficiently map E-CCH payload, allowing implicit indication of DMRS configuration to User Equipment (UE).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DMRS resources are allocated for multiple E-CCHs in one RB, then the control channel capacity is increased, but the resource overhead and system load increase
Solution Approach 1:
The patent segments the control channel into multiple E-CCHs that can be independently scheduled and multiplexed within a single Resource Block. This segmentation allows the system to increase control channel capacity by accommodating multiple control channels simultaneously while managing resource allocation efficiently through separate scheduling of each E-CCH.
Solution Approach 2:
The patent combines multiple E-CCHs and their corresponding DMRS resources within a single Resource Block. By merging these elements, the system achieves higher control channel capacity utilization while reducing overall resource overhead compared to allocating separate RBs for each control channel.
2Reliability
If separate signaling is used to indicate DMRS configuration to UE, then the UE can accurately decode control channel, but the signaling overhead increases
Solution Approach 1:
The patent implements a self-service mechanism where the UE autonomously determines DMRS configuration parameters based on pre-defined rules and the aggregation level of the control channel. The UE uses the aggregation level information to implicitly identify the number of DMRS ports and other configuration details without requiring explicit signaling from the base station, thereby eliminating signaling overhead while maintaining decoding accuracy.
3Reliability
If aggregation level is increased to improve control channel reliability, then decoding success rate improves, but resource consumption increases
Solution Approach 1:
The patent employs dynamic aggregation level selection where the system adjusts the aggregation level of E-CCH based on channel conditions and traffic requirements. This dynamic approach allows the system to achieve reliable decoding when necessary while conserving resources during better channel conditions, optimizing the trade-off between reliability and resource consumption.
Data Source
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AI summary
In legacy systems such as 3rd Generation Partnership Project (3GPP) releases 8 to 10, the control channel is transmitted using the first few Orthogonal Frequency Division Multiplexing (OFDM) symbols in a subframe. The limited control channel capacity will impact the system performance in future releases as more and more User Equipments (UEs) will be scheduled in a subframe with technologies such as MulitUser-Multiple Input Multiple Output (MU-MIMO) and Coordinated Multipoint (CoMP) transmission being enhanced or introduced. A new Enhanced Control CHannel (E-CCH) is necessary to be designed, which will use the resource in the Physical Downlink Shared CHannel (PDSCH) in the legacy systems. The E-CCH will support UE-specific DeModulation Reference Signal (DMRS) based transmission and receiving. However, the configuration of DMRS for E-CCH is necessary to be known to UE in prior. This invention discloses multiple methods in which DMRS is configured for E-CCHs and respective eNB and UE behaviors.