Femto Gateway Handover Processing for Seamless Call Continuity
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Solution Overview
Problem
In wireless communication systems, the implementation of local call switch functions in femtocells leads to call interruptions during handover operations between femtocells and macrocells, as control messages do not enter the core network, and established calls cannot utilize the local call switch function when users move between network scopes.
Innovation Solution
A method and system where a femto gateway receives handover requests, sets up call paths between the femto and core networks, and modifies call resources to ensure seamless handover and continued local call service by establishing a first call path with the core network and acquiring a second call path to the macro network, allowing for resource modifications to maintain communication without interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If local call switch function is enabled in femtocell, then core network overhead is reduced, but call interruption occurs during handover to macro network
Solution Approach 1:
The gateway establishes a preliminary call path to the core network before handover occurs. When a handover request is received, the gateway has already prepared the signaling path, allowing it to quickly forward handover requests to the core network without interruption. This preliminary setup ensures that call continuity is maintained while still enabling local call switching to reduce core network overhead.
2Loss of information
If call path goes through core network, then handover information is available, but local call switch function cannot be used
Solution Approach 1:
The gateway acts as an intermediary between the femtocell and the core network. It maintains a call path to the core network for receiving handover information, while simultaneously enabling local call switching for calls that don't require core network involvement. The gateway intelligently routes traffic: using local switching when applicable to reduce overhead, and involving the core network only when necessary for handover management.
3Loss of time
If handover request is handled locally at femtocell, then response time is reduced, but call setup information is lost
Solution Approach 1:
The handover process is segmented into two parts: time-critical signaling operations are handled locally at the gateway to reduce response time, while call setup information management is segmented to be maintained through the established call path to the core network. This segmentation allows the gateway to quickly process handover requests locally while ensuring call setup information is preserved through the core network path.
Data Source
AI summary
Methods for processing messages in a wireless communication system including a femto network (FN) including at least one Home NodeB, a core network (CN), a macro network (MN) including a serving base station and a gateway located between the FN and the CN is provided. First, a handover request is received from the Home NodeB or a server of the CN when two mobile devices are communicating. When the handover request is received from the Home NodeB, the gateway transmits a call setup request to the CN to setup a first call path between the gateway and the CN according to the handover request, transmits the handover request to the CN through the first call path to obtain a second call path from the CN to the FN and directs the server to perform the handover request according to the first call path and the second call path.