DMRS Resource Allocation for E-PDCCH

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Solution Overview

Problem

In LTE communication systems, the existing pilot resource allocation methods for Enhanced Physical Downlink Control Channel (E-PDCCH) lead to inefficient utilization of time-frequency resources due to the assumption of maximum DMRS resource elements, resulting in idle resources and reduced capacity.

Innovation Solution

The proposed method allocates resource elements (REs) to the demodulation pilot signal (DMRS) based on the aggregation level and multiplexing situation of Enhanced Control Channel Elements (E-CCEs), allowing different numbers of REs to be allocated for DMRS rather than assuming the maximum, thereby improving resource utilization efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the maximum possible number of REs are assumed to be occupied by DMRS, then the base station and user equipment can ensure sufficient pilot resources for demodulation, but resource elements that are not actually used by DMRS become idle, reducing frequency domain resource utilization

Engineering Contradiction:
Improvedemodulation reliabilityVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the DMRS resource allocation flexible and adaptive rather than fixed. The number of REs allocated to DMRS dynamically adjusts according to the actual number of antenna ports used in each RB pair, which varies based on the number of multiplexed E-PDCCHs. This dynamic allocation ensures sufficient pilot resources for reliable demodulation while avoiding idle REs, thus resolving the contradiction between reliability and resource utilization efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of DMRS RE allocation from a fixed maximum value to a variable value that depends on the actual number of antenna ports. By introducing a mapping relationship between the number of multiplexed E-PDCCHs and the number of DMRS REs, the system adapts the pilot resource allocation to actual channel conditions and scheduling requirements, improving resource utilization while maintaining demodulation reliability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the number of user equipments scheduled at the same time is increased through MIMO technology, then the system capacity is improved, but the number of antenna ports used in each RB pair becomes undetermined, making it impossible to accurately determine the number of REs actually used by DMRS

Engineering Contradiction:
Improvesystem capacityVSAvoidresource allocation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback by establishing a mapping relationship between the number of multiplexed E-PDCCHs and the number of DMRS REs. The base station determines the actual number of antenna ports used based on the scheduling information, and this information is reflected in the resource allocation. This feedback mechanism allows the system to accurately determine DMRS RE usage while supporting multiple users through MIMO, resolving the contradiction between system capacity and resource allocation complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by pre-establishing a mapping relationship between the number of multiplexed E-PDCCHs and the number of DMRS REs. This preliminary configuration allows both the base station and user equipment to determine the actual DMRS RE usage before demodulation occurs, eliminating the uncertainty caused by dynamic MIMO scheduling and enabling accurate resource allocation for multiple users.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If resource scheduling is performed on E-PDCCH in a frequency domain resource of the LTE with a resource block pair as a unit, then the resource allocation flexibility is improved, but the number of antenna ports used by an RB pair is undetermined, leading to idle REs

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidfrequency domain resource utilization
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent changes the parameter of DMRS RE allocation from a fixed value to a variable value that adapts to the actual number of antenna ports in each RB pair. By introducing a mapping relationship that links the number of multiplexed E-PDCCHs to the number of DMRS REs, the system achieves flexible resource allocation while avoiding idle REs, thus resolving the contradiction between adaptability and resource utilization.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2660994B1Method and device for allocating reference resource
Publication Date: 2019.04.17 HUAWEI TECH CO LTD
  • EP2660994B1 patent drawingFigure 1
  • EP2660994B1 patent drawingFigure 2
  • EP2660994B1 patent drawingFigure 3~4

AI summary

The present invention provides a pilot resource allocation method, where the method includes: determining, according to an aggregation level and multiplexing information of an enhanced control channel element E-CCE in a resource block pair, the number of resource elements REs that are allocated to and occupied by a demodulation pilot signal DMRS in the resource block pair. The present invention further provides a corresponding user equipment. By implementing the method and device provided by the present invention, the efficiency of time-frequency resource utilization can be improved.