Packet Reordering Control for Radio Access Networks
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Solution Overview
Problem
Packet-switched networks often experience out-of-order packet delivery due to factors like retransmission over air interfaces and load balancing, which can introduce excessive buffering delays, particularly problematic for delay-sensitive applications like multimedia.
Innovation Solution
A method that reads header information to determine the proper sequence of packets, stores out-of-order packets, and forwards them with a controlled degree of misordering, using a configurable parameter to limit the misordering within a specified range, allowing for both in-order and out-of-order delivery in packet networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If packets are reordered using a buffer to ensure in-order delivery, then packet delivery reliability is improved, but transmission delay increases
Solution Approach 1:
The patent applies partial reordering by only reordering packets when the out-of-order degree is within a tolerable range. Instead of reordering all out-of-order packets, the system selectively reorders only those that can be decoded by the upper layer, thereby reducing buffering delay while maintaining delivery reliability for acceptable cases
Solution Approach 2:
The patent introduces a configurable parameter (maximum out-of-order degree) that controls the reordering behavior. By adjusting this parameter, the system can balance between reliability and delay based on specific application requirements, allowing flexible optimization of the contradiction
2Reliability
If reordering is performed at every network segment, then packet delivery reliability is improved, but cumulative delay increases excessively
Solution Approach 1:
The patent extracts the reordering function from individual network segments and consolidates it at the end-to-end transmission level. By performing reordering only at the final destination rather than at each intermediate segment, the system eliminates cumulative buffering delay while maintaining delivery reliability through single-point reordering
Solution Approach 2:
The patent merges multiple reordering operations into a single reordering operation at the end-to-end level. Instead of each network segment independently reordering packets (which causes cumulative delay), the system combines all reordering needs into one operation, reducing total delay while achieving the same reliability goal
3Loss of time
If out-of-order packets are delivered to support delay-sensitive applications, then transmission delay is reduced, but packet delivery reliability deteriorates
Solution Approach 1:
The patent controls the out-of-order degree as a configurable parameter, allowing the system to deliver packets out-of-order when beneficial for delay-sensitive applications while limiting the maximum out-of-order degree to maintain upper layer decodability. This parameter control enables flexible trade-off between delay and reliability
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors the out-of-order degree and adjusts reordering behavior based on upper layer decoding success. When packets arrive out-of-order within the tolerable range, the system delivers them immediately; when the out-of-order degree exceeds the threshold, reordering is triggered, creating a feedback loop that balances delay and reliability
Data Source
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AI summary
A method is provided for controlling the misordering of packets in packet delivery in radio access networks (RANs) and other packet-switched networks. In one aspect, the method involves reading header information to determine the proper sequence of arriving packets, storing at least some packets that have arrived out of order, and forwarding the stored packets in a modified order that has no more than a specified degree of misordering.