Wireless Protocol Stack Packet Transfer Integrity
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Solution Overview
Problem
Current mobile wireless communication systems, particularly those using GPRS and UMTS technologies, face challenges in ensuring successful data packet transmission due to lack of acknowledgement mechanisms in unacknowledged modes, leading to packet loss during technology switches, especially in delay-sensitive services like video telephony.
Innovation Solution
A method and system for confirming successful data packet transfer by receiving an indication from a lower layer of the protocol stack, allowing for packet retransmission and reducing losses during technology switches by maintaining packet integrity across protocol stack layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If unacknowledged mode of operation is used for data packet transmission, then transmission speed is improved, but packet loss increases during technology switches
Solution Approach 1:
The patent introduces an internal feedback mechanism where the first layer monitors the transmission status of data packets to the lower layer. When a technology switch occurs, the first layer receives feedback about unacknowledged packets and can retransmit them through the new technology path, thus maintaining reliability while using fast unacknowledged mode transmission.
Solution Approach 2:
The patent implements preliminary tracking of data packet transmission status at the first layer before technology switches occur. By maintaining knowledge of which packets have been sent but not acknowledged, the system can proactively handle retransmission needs when switching technologies, preventing packet loss before it happens.
2Reliability
If technology switch is performed for better signal conditions, then connection quality is improved, but unacknowledged data packets may be lost
Solution Approach 1:
The monitoring mechanism provides feedback about packet transmission status to the first layer. When a technology switch is initiated for better signal conditions, this feedback enables the system to identify which packets need retransmission, ensuring no data is lost during the quality-improving switch.
Solution Approach 2:
The first layer acts as an intermediary between the data source and the lower transmission layers. It buffers and tracks packet status information, mediating the transfer of data across technology boundaries to ensure continuity and prevent loss during switches.
3Reliability
If acknowledged mode is used for packet transmission, then packet delivery reliability is improved, but transmission latency increases
Solution Approach 1:
Instead of implementing full acknowledged mode with complete feedback loops, the patent applies partial acknowledgment by monitoring packet status at the first layer and selectively retransmitting only unacknowledged packets after technology switches. This provides sufficient reliability without the full latency overhead of traditional acknowledged mode.
Data Source
AI summary
The invention is directed to a process for transferring data packets through a protocol stack employed by the device for transmitting packets on a packet connection to a wireless network, said wireless network operating at least two, distinct wireless access technologies such as GSM/GPRS and UMTS. The packet transfer process generally comprises each layer of a protocol stack for a currently active packet connection path providing confirmation to a next, higher layer in the stack of successful reception of a data packet from that layer, thereby confirming successful transfer of the data packet through the stack. The first layer of the stack stores a copy of a transferred packet until such time as its receives confirmation from the next, lower layer of successful transfer of the packet of the stack. In the absence of such confirmation and on the occurrence of a switch (hand-off) of the packet connection to a new connection path, particularly one of a different wireless access technology, the stored packet is transferred to the protocol stack to be employed by the wireless device for the new packet connection path. Consequently, the packet transfer process avoids packets being lost on the occurrence of a switch between different technology wireless access packet connection paths.