User Equipment Handover Context Retention
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Solution Overview
Problem
Current 3GPP standards do not ensure seamless handover of real-time sessions when user equipment (UE) transitions from Wi-Fi to cellular coverage, leading to service interruptions and data loss due to reconfiguration delays.
Innovation Solution
The UE uses initial context information for a specified duration during handover from one packet data network to another, acquiring and comparing new context information to ensure continuous communication without interruption, allowing for either continued use of the initial or new context information based on equivalence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE reconfigures prefix and interface identifier information over the cellular radio interface when moving from Wi-Fi to cellular coverage, then the UE can establish a PDN connection with the cellular network, but the communication session experiences interruption and service discontinuity during the reconfiguration process
Solution Approach 1:
The network side performs preliminary actions by establishing a PDN connection and allocating IP address information before the UE completes the handover. The network pre-configures the cellular interface with necessary IP address information (IPv4 or IPv6) so that when the UE switches from Wi-Fi to cellular, the communication session can continue without interruption. This preliminary setup eliminates the need for the UE to perform time-consuming reconfiguration procedures after handover.
2Adaptability or versatility
If the UE sends a PDN connectivity message and initiates reconfiguration, then the UE can acquire IPv6 prefix and IID information from the packet gateway, but the UE cannot send uplink data or recognize downlink data during the reconfiguration process
Solution Approach 1:
The patent ensures continuous data transmission capability during handover by maintaining the same IP address information across both Wi-Fi and cellular interfaces. The network allocates identical IP address information to the UE's cellular interface that matches the Wi-Fi interface, allowing data transmission to continue uninterrupted. The UE can send uplink data and recognize downlink data on both interfaces simultaneously, eliminating the productivity loss that would otherwise occur during reconfiguration.
3Ease of operation
If the UE uses router solicitation and router advertisement messages to acquire IP address information, then the UE can obtain IPv6 prefix and IID information, but additional delays occur due to potential message loss over the best effort lossy link
Solution Approach 1:
The network side acts as an intermediary by directly providing IP address information to the UE through the PDN connection establishment process, bypassing the need for Router Solicitation and Router Advertisement message exchanges. This intermediary approach eliminates the uncertainty and delays associated with best-effort lossy links, as the IP address information is reliably transmitted as part of the standardized PDN connection setup procedure controlled by the network.
Data Source
AI summary
In some embodiments, a user equipment device (UE) may be configured to perform handover of a communication session from a first packet data network (PDN) to a second PDN. The UE may include a radio and processing circuitry coupled to the radio and configured to interoperate with the radio. The radio may include one or more antennas for performing wireless communications over at least a first packet data network (PDN) (i.e., packet-switched network) and a second PDN. The UE may be configured to communicate over the first PDN according to first context information that was assigned to the UE and initiate a handover operation from the first PDN to the second PDN. In response to initiating the handover operation, the UE may communicate over the second PDN using the first context information for at least a first time duration.