Heterogeneous Network Offloading and Handover Coordination
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Solution Overview
Problem
Heterogeneous wireless communication networks face challenges with increased handovers and radio link failures due to interference between overlay and existing cellular networks, particularly when low-power cells are deployed with the same carrier frequency as macro cells, leading to unnecessary handovers and load balancing burdens.
Innovation Solution
The method involves maintaining simultaneous radio link connections with both a macro cell and a low-power cell, allowing for data and control offloading without switching the data path, using a two-bit offloading flag in RRC reconfiguration messages to manage handovers and reduce radio link failures by coordinating between base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If low-power cells are deployed with the same carrier frequency as macro cells, then cell coverage and traffic offloading are improved, but interference between cells increases leading to radio link failures
Solution Approach 1:
The patent segments the frequency resources by assigning different carrier frequencies to macro cells and low-power cells. This frequency segmentation eliminates interference between the two cell types while allowing both to operate simultaneously, thus improving coverage without suffering from inter-cell interference
Solution Approach 2:
The patent introduces frequency as a distinguishing dimension between macro and low-power cells. By operating in different frequency dimensions rather than the same frequency, the system allows both cell types to coexist without interference, effectively adding a spectral dimension to the network architecture
2Productivity
If frequent handovers are performed between macro cells and low-power cells, then load balancing is improved, but network stability deteriorates due to increased handover failures
Solution Approach 1:
The patent performs preliminary actions by pre-configuring frequency-specific parameters and offloading information in RRC messages before handovers occur. This preparation reduces the complexity and failure rate of actual handover execution, thereby improving network stability while maintaining load balancing capabilities
Solution Approach 2:
The patent introduces an intermediary mechanism through the eNB that manages and coordinates handovers between macro and low-power cells. The eNB uses offloading flags and frequency information to mediate handover decisions, reducing unnecessary handovers and improving overall network stability
3Reliability
If data path switching is performed during handover, then connection to target cell is established, but unnecessary handovers increase due to interference conditions
Solution Approach 1:
The patent applies partial action by selectively performing data path switching only when necessary, based on offloading flags and frequency information. Instead of always switching data paths during handover, the system performs partial switching only for cells that require it, reducing unnecessary handovers and improving efficiency
Data Source
AI summary
Systems, methods, and apparatuses for data and/or control offloading and handover in heterogeneous wireless communication networks are provided. Data and/or control packets can be offloaded to a coordinating base station while a user equipment (UE) remains associated with its serving cell. The packets are still transferred between the serving base station and the core network, and the offloaded data and/or control packets are forwarded from the serving base station to the coordinating base station for transmission to the UE. Furthermore, during a handover process, the serving base station and coordinating base station may independently schedule and send a handover command to the UE to reduce the radio link failure rate.