PUCCH Format 3 Resource Allocation for TDD Carrier Aggregation
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Solution Overview
Problem
Current 4G radio access network (RAN) configurations using PUCCH Format 3 resource allocation limit Carrier Aggregation (CA) capacity to only 10 UEs in Time Division Duplex (TDD) systems, restricting the number of users that can utilize CA due to resource blocking and high overhead, which negatively impacts uplink throughput.
Innovation Solution
Implementing a method that utilizes Layer 3 RRC, Layer 2 MAC Scheduler, and Layer 2 Reserve PUCCH Format 3 sub-routine to configure and manage PUCCH resources, allowing for increased CA capacity by configuring 4 PUCCH Format 3 resources per UE, maintaining a lookup table for resource allocation, and prioritizing UE scheduling based on buffer occupancy and resource availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of RBs for PUCCH format 3 is increased to support more CA UEs, then the CA capacity increases, but the PUCCH overhead increases and UL throughput decreases
Solution Approach 1:
The patent segments the PUCCH resource allocation into multiple layers: L3 RRC layer configures 4 candidate resources per UE, while L2 MAC layer dynamically selects and reserves specific resources. This segmentation allows efficient resource utilization without increasing total RB allocation, resolving the contradiction between supporting more UEs and maintaining UL throughput.
Solution Approach 2:
The patent implements preliminary action by pre-configuring 4 PUCCH Format 3 resources for each UE at the L3 RRC layer before actual scheduling occurs. This advance preparation enables rapid L2 resource selection and reduces blocking probability, allowing support for 200 UEs without proportionally increasing overhead.
2Reliability
If only 10 CA UEs are scheduled with dedicated PUCCH format 3 resources, then resource blocking is minimized, but the system cannot support the full 200 TDD UEs
Solution Approach 1:
The patent introduces dynamic resource selection at the L2 MAC layer, where the specific PUCCH Format 3 resource is selected based on real-time scheduling decisions and buffer occupancy conditions. This dynamic approach allows the system to adapt resource allocation to actual needs, supporting up to 200 UEs while maintaining reliability through the pre-configured pool of 4 resources per UE.
Solution Approach 2:
The patent changes the parameter of PUCCH resource configuration from a fixed 1:1 mapping (10 UEs to 10 resources) to a many-to-few mapping (200 UEs to 400 total resources across all UEs). Each UE is configured with 4 candidate resources, but not all are simultaneously active, effectively increasing CA capacity while controlling overhead.
3Reliability
If PUCCH format 3 resources are reserved for CA UEs, then HARQ-ACK feedback reliability improves, but resource availability for other UEs decreases
Solution Approach 1:
The patent makes PUCCH Format 3 resources universal by configuring the same pool of 4 candidate resources to serve multiple CA UEs through dynamic selection. The L2 MAC layer reserves resources based on actual scheduling needs, allowing the same physical resources to be shared across different UEs at different times, thus maintaining HARQ-ACK reliability while improving overall resource availability and system adaptability.
Data Source
AI summary
A system for optimizing Physical Uplink Control Channel (PUCCH) Format 3 resource assignment in 4G Radio Access Network (RAN) includes: a Layer 3 (L3) Radio Resource Control (RRC) module configured to selectively configure four PUCCH Format 3 resources for each one of user equipments (UEs) which attach or hand-in to a serving cell of the RAN, the L3 RRC module configuring the four PUCCH Format 3 resources from a PUCCH Format 3 UE-configuration lookup table structured to balance the number of assignments to each of ten PUCCH Format 3 resources; and a Layer 2 (L2) Media Access Control (MAC) Scheduler configured to selectively reserve one of PUCCH Format 1 resource or PUCCH Format 3 resource depending on buffer occupancy (BO), the selective reservation of PUCCH Format 3 resource being accompanied by updating an L2 Format 3 Reserved bitmap to track the PUCCH Format 3 resources in a Bundling Period.