Intercepting NACK Messages to Prevent Wireless Retransmission
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Solution Overview
Problem
Wireless communication networks experience substantial delays and inefficient resource utilization due to retransmission of dropped data packets, particularly in TCP sessions, as they rely on scarce wireless channels, which are time-varying and prone to multipath fading and Doppler shift, leading to unnecessary usage and congestion.
Innovation Solution
A method and system that distribute TCP sessions across network elements, intercepting NACK messages and retransmitting data packets through wired channels instead of wireless ones, preventing repetitive wireless channel usage and optimizing resource management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data packets are retransmitted through wireless communication channels when dropped, then TCP reliability is maintained, but wireless communication resources are unnecessarily consumed and transmission delays increase
Solution Approach 1:
The patent introduces network elements (eNodeB, proxy server) as intermediaries between the mobile station and the TCP session. These intermediaries intercept NACK messages and handle retransmission of dropped packets through wired channels, preventing mobile stations from directly retransmitting over wireless channels. The intermediary absorbs the retransmission function, protecting the wireless resource from unnecessary consumption while maintaining TCP reliability.
Solution Approach 2:
The patent segments the TCP retransmission function from the mobile station and relocates it to network elements. By dividing the end-to-end TCP session into segments handled by different network components, the mobile station is relieved of the burden of wireless retransmission, which is then performed by network elements using more efficient wired channels for the backhaul connection.
2Reliability
If mobile stations retransmit dropped data packets over wireless channels, then data integrity is preserved, but transmission time increases due to time-varying wireless channel conditions
Solution Approach 1:
Network elements serve as intermediaries that perform retransmission using wired channels with more stable and predictable transmission characteristics. This intermediary approach eliminates the time-varying wireless channel constraints from the retransmission path, significantly reducing retransmission delays while preserving data integrity through the same TCP mechanism.
3Ease of operation
If TCP sessions are centralized at mobile stations, then end-to-end protocol control is maintained, but wireless communication channels are congested with retransmission traffic
Solution Approach 1:
The patent introduces network intermediaries that take over the retransmission function while maintaining TCP session continuity. These intermediaries transparently handle NACK messages and retransmit packets without requiring changes to the mobile station's TCP implementation, thus preserving end-to-end control semantics while improving wireless channel productivity by eliminating unnecessary retransmission traffic.
Solution Approach 2:
Network elements are given multiple functions: they continue to perform traditional routing and switching while also intercepting NACK messages and performing TCP-level retransmission management. This multi-functionality allows the network infrastructure to absorb the retransmission burden without requiring separate dedicated systems, efficiently utilizing existing resources to improve wireless channel availability.
Data Source
AI summary
A system for circumventing retransmission of dropped data packets from a source mobile station is envisaged. The source mobile station is coupled to a destination mobile station. The source mobile station and destination mobile station are coupled to a source eNodeB and a destination eNodeB respectively. The source eNodeB and the destination eNodeB are configured to interpret any No Acknowledgement (NACK) messages transmitted from the destination mobile station on account of non receipt of data packets transmitted from the source mobile station, and accordingly retransmit, from a buffered data packet pool, the data packets corresponding to the NACK messages. The source eNodeB and destination eNodeB prevent NACK messages from being retransmitted to the source mobile station thereby obviating the need for the source mobile station to retransmit dropped data packets, and rendering the source mobile station available for any subsequent data transfer operations.