Dynamic MTU Size Selection for Wireless Data Transfer
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Solution Overview
Problem
In LTE wireless communication systems, Category-M devices experience high TCP session failure rates due to poor radio signal conditions, which lead to increased TCP packet retransmissions and timeouts when multiple devices concurrently download or upload data, especially under limited radio resources and long round trip delays.
Innovation Solution
The technology dynamically selects a maximum transmission unit (MTU) packet size based on radio signal conditions, using a smaller MTU size in poor signal conditions to reduce the number of radio blocks required for data transmission, thereby decreasing TCP retransmission and timeout rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger MTU packet size is used for data transmission, then the data transfer efficiency is improved, but the TCP retransmission rate increases under poor radio signal conditions
Solution Approach 1:
The patent implements dynamic MTU size adjustment by continuously monitoring radio signal conditions (RSRP, RSRQ, SINR) and adapting the MTU packet size accordingly. The system transitions from a static MTU configuration to a dynamic one where the MTU size changes in real-time based on channel quality, resolving the contradiction between maintaining high data transfer efficiency and ensuring reliable TCP sessions under varying radio conditions
Solution Approach 2:
The patent changes the transmission parameter (MTU size) based on measured radio signal conditions. By adjusting the MTU size parameter according to RSRP, RSRQ, and SINR measurements, the system optimizes the balance between transmission efficiency and reliability, using larger MTU sizes when signal conditions are good and smaller MTU sizes when conditions deteriorate
2Reliability
If the number of radio blocks per TCP packet is increased to reduce retransmissions, then the probability of complete packet loss increases under poor signal conditions
Solution Approach 1:
The patent applies partial action by sending TCP packets with a controlled number of radio blocks based on signal conditions. Rather than always using the maximum number of blocks (which would increase loss probability) or always using minimal blocks (which would increase retransmissions), the system dynamically determines the optimal number of blocks to transmit, achieving a balance between these two opposing risks
3Device complexity
If a fixed MTU size is used for simplicity, then the device complexity is reduced, but the TCP session failure rate increases under varying radio conditions
Solution Approach 1:
The patent implements self-service by enabling the Cat-M device to autonomously monitor its own radio signal conditions and automatically adjust its MTU size without external intervention. The device performs self-diagnosis of channel quality and self-adjustment of transmission parameters, eliminating the need for complex network-side control mechanisms while improving TCP session reliability under varying conditions
Data Source
AI summary
The described technology is generally directed towards selecting, by user equipment, a selected maximum transmission unit (MTU) packet size for wireless data transfer based on radio signal conditions. In one aspect, reference signal received power (RSRP) and reference signal received quality (RSRQ) are used to select the MTU packet size, e.g., by using RSRP and RSRQ as indices to a lookup table of predetermined MTU packet sizes, such as previously determined by field testing. In general, smaller MTU packet sizes are used with poorer quality radio signal conditions. The selected MTU packet size may be increased or decreased based on actual performance data and/or based on changed radio signal conditions, such as for a subsequent data transfer session. The user equipment may comprise a Cat-M device that transfers data related to Machine-Type Communications (MTC)/Machine to Machine (M2M) communications.