PDCCH Power Coordination for Shared Cell Capacity

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Solution Overview

Problem

In shared cell scenarios of mobile communication networks, the physical downlink control channel (PDCCH) often becomes a bottleneck, limiting capacity and peak throughput due to inefficient power allocation and resource sharing between adjacent cells with the same Physical Cell Identity (PCI).

Innovation Solution

A method and system for PDCCH power coordination between two transmission points associated with a common PCI, where power is adjusted on control channel elements (CCEs) to optimize allocation, reducing the number of CCEs allocated to one user equipment (UE) to free up resources for others, allowing more UEs to be scheduled without specific UE support, and enhancing capacity and peak rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PDCCH size is increased to schedule more UEs, then scheduling capacity is improved, but available resources for PDSCH decrease, reducing peak throughput and cell capacity

Engineering Contradiction:

Improvescheduling capacityVSAvoidavailable resources for PDSCH

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent implements dynamic PDCCH power adjustment where transmission points can adaptively modify PDCCH power levels based on current network conditions, UE requirements, and resource availability. This allows the system to optimize the balance between PDCCH capacity and PDSCH resources in real-time, rather than using fixed resource allocations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the power parameter of PDCCH transmissions to optimize resource utilization. By adjusting power levels dynamically, the system can schedule more UEs when power is increased, or allocate more resources to PDSCH when power is reduced, thus resolving the contradiction between scheduling capacity and available data transmission resources.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If PDCCH is reused in cells with the same PCI to increase capacity, then scheduling capacity is improved, but PDCCH performance degrades for cell-edge UEs due to interference

Engineering Contradiction:

Improvescheduling capacityVSAvoidPDCCH performance for cell-edge UEs

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies different power levels to different transmission points within the same shared cell. Transmission points can assign different PDCCH power levels to different UEs or different time/frequency resources, allowing cell-center UEs to benefit from higher capacity while cell-edge UEs receive sufficient power to maintain reliable connections despite interference from adjacent cells with the same PCI.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system implements feedback mechanisms where transmission points monitor PDCCH reception quality for cell-edge UEs and adjust power levels accordingly. This feedback loop ensures that PDCCH performance for vulnerable cell-edge UEs is maintained while still allowing overall capacity to be increased through PDCCH reuse in shared cells.

Inventive Principle:

Principle #23Feedback

3Reliability

If common PDCCH is used in cells with the same PCI to protect cell-edge UEs, then PDCCH performance is improved, but scheduling capacity is limited

Engineering Contradiction:

ImprovePDCCH performance for cell-edge UEsVSAvoidscheduling capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent enables dynamic power adjustment where transmission points can switch between common PDCCH and cell-specific PDCCH configurations based on current network conditions. When cell-edge UE protection is prioritized, common PDCCH with higher power is used; when capacity is prioritized and conditions allow, cell-specific PDCCH with lower power is used to free up resources.

Inventive Principle:

Principle #15Dynamics

4Reliability

If power is allocated to ensure adequate PDCCH coverage for all UEs, then reliability is improved, but fewer resources remain for scheduling additional UEs

Engineering Contradiction:

ImprovePDCCH coverageVSAvoidnumber of schedulable UEs

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements differentiated power allocation where different power levels are assigned to different UEs, time slots, or frequency resources based on their specific requirements. UEs with poor channel conditions or at cell edges receive higher power allocations to ensure reliable PDCCH reception, while UEs with good channel conditions receive lower power allocations, freeing up resources to schedule additional UEs.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9949213B2Physical downlink control channel power coordination

Publication Date: 2018.04.17 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided physical downlink control channel (PDCCH) power coordination. A first transmission point (TP1) and a second transmission point (TP2) are associated with a common physical cell identity (PCI). TP1 and TP2 are controlled by a network node. The network node schedules a first user equipment (UE1) on a first PDCCH allocating a first set of control channel elements (CCEs). TP1 and TP2 adjust power on at least one CCE in the first set of CCEs allocated to UE1. TP1 adjusts power on at least one CCE in a second set of CCEs. The second set of CCEs is allocatable by a second PDCCH for the network node to schedule at least a second user equipment (UE2). TP1 and TP2 decrease the number of CCEs in the first set of CCEs allocated to UE1.