Mobile Terminal Relocation Across SGWs With Stable IP Routing
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining seamless connectivity and minimizing latency for mobile terminals traveling across large geographic distances, as they typically require changing packet data network gateways (PGWs) which disrupt established connections and introduce latency due to long-distance data transmission.
Innovation Solution
Implementing a method for seamless relocation of mobile terminals to different PGWs using Software-Defined Networking (SDN) controllers to dynamically reconfigure routing and maintain the same IP address, allowing for optimized traffic patterns and continuous connectivity by establishing new communication channels without disrupting existing sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the terminal changes its homed PGW during travel, then the data transmission distance is reduced and latency is improved, but all established connections based on source and destination IP addresses between the terminal and its service providers will be disconnected
Solution Approach 1:
The patent segments the PGW functionality into two independent components: the IP address management function (maintained by the home PGW) and the data transmission function (handled by the serving PGW). This allows the terminal to change serving PGWs for optimized data transmission while maintaining its home PGW for IP address stability, thus resolving the contradiction between reducing latency and maintaining connection continuity.
Solution Approach 2:
The home PGW acts as an intermediary between the terminal and the serving PGW. It maintains the terminal's IP address and routing information, while the serving PGW handles actual data transmission. This intermediary structure enables seamless PGW relocation by allowing the home PGW to update routing information without requiring IP address changes, thereby maintaining connection continuity while optimizing data transmission paths.
2Reliability
If the terminal remains anchored to the same PGW during long-distance travel, then connection stability is maintained, but data transmission experiences long-distance latency
Solution Approach 1:
The patent divides the PGW role into home PGW (for anchoring and IP management) and serving PGW (for local data transmission). The terminal remains anchored to the home PGW ensuring connection stability, while the serving PGW is dynamically selected based on terminal location to minimize transmission distance and latency.
Solution Approach 2:
The patent introduces a new dimensional structure to the network architecture by separating the anchoring function from the transmission function across different PGWs. This creates a two-layer PGW structure where the home PGW provides temporal stability (time dimension) and the serving PGW provides spatial optimization (location dimension), simultaneously achieving connection stability and reduced latency.
3Ease of operation
If the terminal handovers between different SGWs during travel, then local network coverage is maintained, but the data transmission path may become suboptimal if the PGW remains distant
Solution Approach 1:
The patent makes the serving PGW assignment dynamic rather than static. When the terminal handovers between SGWs, the system dynamically evaluates whether to keep the same serving PGW or select a new one based on current terminal location and network conditions. This dynamic adjustment ensures that data transmission paths remain optimized even as the terminal moves through different network coverage areas.
Solution Approach 2:
The system implements feedback mechanisms where the SGW and MME monitor terminal location and network conditions, and trigger serving PGW reselection when optimization is needed. This feedback loop ensures that the serving PGW assignment adapts to changing terminal positions, maintaining optimal data transmission paths while the terminal handovers between different SGWs for coverage continuity.
Data Source
AI summary
A method for performing seamless relocation of a mobile terminal in a wireless network includes selecting a first serving gateway (SGW) among a plurality of SGWs and a first packet data network gateway (PGW) among a plurality of PGWs, wherein the first SGW connects to the first PGW to setup the first S5 session, establishing a first communication channel between the terminal and the first PGW and assigning an internet protocol (IP) address to the terminal, selecting a second SGW among the plurality of SGWs when the terminal is about to move out of an area being served by the first SGW, connecting the second SGW to the second PGW to setup a new S5 session when a second PGW among the plurality of PGWs is closer to the second SGW than the first PGW or connecting the second SGW to the first PGW to modify the first S5 session when no PGW is closer to the second SGW than the first PGW, establishing a second communication channel between the terminal and the second SGW using the IP address allocated to the terminal, reconfiguring routing for terminal IP destination, and terminating the first communication channel between the terminal and the first PGW.