Subframe Scheduling in Split MAC RAN via Resource Block Gaps

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Solution Overview

Problem

In split Medium Access Control (MAC) Radio Access Network (RAN) environments, there are challenges in centralizing control of communication network resources, particularly with regard to timing constraints for subframe scheduling for user equipment, leading to inefficiencies in managing communication network resources and handling retransmissions.

Innovation Solution

The system and method facilitate subframe scheduling by adaptively reserving resource block gaps in the RAN controller, allowing for deterministic air interface scheduling and efficient handling of downlink and uplink retransmissions through quantized RB allocation sizes and feedback mechanisms, enabling flexible resource allocation for resource-constrained scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If control of communication network resources is centralized in a split MAC RAN environment, then resource management efficiency is improved, but timing constraints for subframe scheduling are violated leading to increased latency

Engineering Contradiction:

Improveresource management efficiencyVSAvoidsubframe scheduling latency

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent segments the MAC layer into distributed MAC entities at RRUs and a centralized MAC controller, allowing local scheduling decisions at RRUs while maintaining centralized resource management. This segmentation enables subframe scheduling to be handled locally without violating timing constraints, while still benefiting from centralized control for overall resource management efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by pre-configuring resource block allocations and scheduling parameters at RRUs based on centralized decisions. The centralized controller provides advance scheduling commands to distributed MAC entities, allowing them to prepare resource allocations before subframes begin, thus meeting timing constraints while maintaining centralized control benefits.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If resource blocks are dynamically allocated to handle retransmissions, then retransmission handling flexibility is improved, but resource block fragmentation increases reducing overall utilization

Engineering Contradiction:

Improveretransmission handling flexibilityVSAvoidresource block fragmentation

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by allowing different resource block allocation strategies at different RRUs based on local retransmission needs. Each distributed MAC entity can dynamically allocate resource blocks for retransmissions based on local channel conditions and queue states, providing flexibility without causing network-wide fragmentation. The localized approach ensures resource blocks are allocated where needed without creating fragmentation across the entire system.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If subframe scheduling is handled centrally, then scheduling control is improved, but timing constraints cannot be met due to processing delays

Engineering Contradiction:

Improvescheduling controlVSAvoidscheduling response time

Core Design Contradiction:

Ease of operationVSSpeed

Solution Approach 1:

The patent introduces an intermediary mechanism where distributed MAC entities at RRUs act as local scheduling intermediaries. These intermediaries receive high-level resource allocation commands from the centralized controller and translate them into specific subframe scheduling decisions locally. This intermediary approach maintains centralized scheduling control while enabling fast local response times that meet timing constraints.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10420134B2System and method to facilitate subframe scheduling in a split medium access control radio access network environment

Publication Date: 2019.09.17 CISCO TECHNOLOGY INC

AI summary

A method is provided in one example embodiment and may include receiving a scheduling command for a subframe at a Remote Radio Unit (RRU), wherein the scheduling command provides a subframe configuration for the subframe; determining whether the subframe configuration comprises at least one resource block gap for the subframe; and if the subframe configuration comprises a resource block gap, utilizing the at least one resource block gap to accommodate one or more previously allocated resource blocks for one or more user equipment served by the RRU for which at least one of a previous downlink transmission has failed or a previous uplink grant has been delayed. In some instances, the subframe configuration can be associated with downlink transmissions and uplink transmissions for one or more user equipment served by the RRU.