Resource Block Allocation for Heterogeneous Network Interference
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Solution Overview
Problem
In heterogeneous networks, user equipment (UE) connected to a macrocell may lose connectivity when entering a femtocell due to resource block interference, especially when the femtocell is in a closed subscriber group mode that the UE is not a member of, leading to handoff rejection and interference.
Innovation Solution
The UE requests resource block allocation from the Mobility Management Entity (MME) to maintain connectivity with the macrocell by using specific resource blocks while within the femtocell, with the MME determining and allocating these blocks to ensure continuous communication through the femtocell without interfering with the femtocell's operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the femtocell utilizes the same resource blocks as the macrocell for communication, then the femtocell can provide service to its subscribed UEs, but the UE connected to the macrocell experiences interference and loses connectivity when entering the femtocell coverage area
Solution Approach 1:
The patent segments the resource blocks into two distinct sets: default resource blocks for femtocell operations and allocated resource blocks for macrocell UEs. This segmentation prevents interference by ensuring that femtocell transmissions and macrocell UE transmissions do not occur on the same frequency resources simultaneously, thereby resolving the contradiction between providing femtocell service and maintaining macrocell connectivity.
Solution Approach 2:
The patent applies local quality by assigning different resource block characteristics to different spatial locations. UEs connected to the macrocell that enter femtocell coverage areas are granted specific allocated resource blocks that are reserved exclusively for their use within the femtocell coverage area, while other resource blocks remain available for femtocell operations. This localized resource differentiation maintains connectivity reliability while preserving femtocell service capability.
2Reliability
If the femtocell operates in closed subscriber group mode to secure service for authorized UEs, then the femtocell can prevent unauthorized access, but authorized UEs connected to the macrocell are rejected during handoff and experience interference
Solution Approach 1:
The patent introduces the MME (Mobility Management Entity) as an intermediary that coordinates resource block allocation between the femtocell and macrocell. When a UE connected to the macrocell enters the femtocell coverage area, the MME intervenes to allocate specific resource blocks to that UE, ensuring the UE can maintain connectivity despite the femtocell's closed subscriber group mode. This intermediary mechanism resolves the contradiction by mediating between access security requirements and connectivity flexibility needs.
Solution Approach 2:
The patent implements preliminary action by pre-allocating resource blocks to macrocell UEs before they potentially experience interference. The MME proactively identifies UEs that may enter femtocell coverage areas and reserves specific resource blocks for their use, preventing connectivity loss before it occurs. This preliminary resource reservation ensures both femtocell access security and UE connectivity flexibility are maintained.
3Reliability
If the UE requests dynamic resource block allocation from the MME when detecting femtocell presence, then the UE can maintain stable connection with the macrocell, but the system requires additional signaling overhead and coordination complexity
Solution Approach 1:
The patent implements self-service by enabling the UE to autonomously detect femtocell presence and initiate resource block allocation requests to the MME. Rather than requiring continuous network-controlled resource management, the UE independently identifies when it enters femtocell coverage and self-starts the resource allocation process. This reduces the overall system complexity by distributing the intelligence and reducing the burden on centralized network entities.
Data Source
AI summary
A device establishes a connection with a user equipment (UE) via a macrocell associated with the device, and provides, to a femto device within range of the macrocell, information identifying resource blocks to allocate to the UE when the UE enters into a femtocell generated by the femto device. The femto device provides the information to the UE when the UE enters into the femtocell. The device also maintains the connection of the UE with macrocell, via the allocated resource blocks identified in the information, when the UE enters into the femtocell.