Data Forwarding via Air Link to Reduce Handover Interruption
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Solution Overview
Problem
In wireless communication systems where macro and femto cells coexist, the HandOver (HO) interruption time is increased due to latency caused by the Internet Service Provider (ISP) network, leading to service cut-offs in VoIP and video streaming, especially when a mobile station (MS) transitions from a macro cell to a femto cell.
Innovation Solution
The solution involves transmitting data packets directly from a macro Base Station (BS) to the MS through an air link instead of a wired link via the backbone network and ISP network, allowing synchronization with both the macro and femto BSs to reduce HO interruption time by bypassing ISP latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data packets are transmitted through the wired link via backbone network and ISP network during handover, then network connectivity is maintained, but HO interruption time increases due to ISP network latency
Solution Approach 1:
The patent segments the data transmission path into two separate paths: a wired link path (through backbone network and ISP network) and a wireless air link path (direct transmission between base stations). This allows selective use of transmission paths based on handover scenarios, enabling the system to bypass the high-latency wired path during critical handover moments by using the direct air link instead.
Solution Approach 2:
The macro base station acts as an intermediary that receives data packets from the mobile station before handover and forwards them directly to the target femto base station through the air link. This intermediary mechanism enables direct wireless transmission of data packets, eliminating the need for packets to traverse the high-latency wired network infrastructure during handover.
2Loss of time
If data packets are transmitted through the air link directly from macro BS to MS, then HO interruption time is reduced, but network complexity increases due to dual path management
Solution Approach 1:
The patent implements dynamic path selection where the data transmission route is automatically adjusted based on the handover state. During handover, the system dynamically switches from the standard wired path to the direct air link path, and after handover completion, returns to the normal wired path. This dynamic adaptation allows the system to optimize performance during critical moments without permanently increasing operational complexity.
Solution Approach 2:
The macro base station performs preliminary actions by receiving and buffering data packets from the mobile station before the handover is complete. This preliminary data collection and preparation enables the macro BS to immediately forward packets through the air link when the opportunity arises, reducing interruption time without requiring complex real-time routing decisions during the actual handover moment.
3Reliability
If HO procedure is performed with target BS, then service continuity is achieved, but service cut-off occurs in VoIP and video streaming due to latency
Solution Approach 1:
The patent ensures continuous data transmission during handover by establishing the direct air link path that remains active throughout the handover process. This continuous transmission path prevents the service interruptions that normally occur when data packets must wait for the completion of wired network routing procedures, thereby maintaining both service continuity and quality for real-time applications like VoIP and video streaming.
Data Source
AI summary
A data forwarding apparatus and method for reducing a HandOver (HO) interruption time in a wireless communication system where a macro cell and a femto cell coexist are provided. An operation method of a Mobile Station (MS) for data forwarding in a wireless communication system includes synchronizing with a serving Base Station (BS) after completing a HO procedure with a target BS, and receiving data packets existing in a queue through an air link directly from the serving BS.