TDM Frame Compression via Dynamic Slot Mapping
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Solution Overview
Problem
Time Division Multiplex (TDM) frame communication over packet networks is inflexible, leading to inefficient use of infrastructure as the packet rate remains constant regardless of the actual capacity usage, resulting in high costs for rented capacity and infrastructure usage.
Innovation Solution
The method involves dynamically adjusting the mapping of TDM frames into transport frames based on allocation information, allowing for seamless re-configuration of mapping and packet transport mechanisms to accommodate varying traffic conditions, thereby eliminating the need to transport unused slots and optimizing the use of infrastructure by dynamically adjusting the number of allocated slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TDM frames are mapped onto a fixed-rate packet stream, then the TDM frame sequence can be reliably transmitted over packet networks, but the packet rate remains high regardless of actual capacity usage, leading to inefficient infrastructure utilization
Solution Approach 1:
The patent applies dynamics by making the packet stream rate variable rather than fixed. The system dynamically adjusts the packetization rate based on the actual number of allocated TDM slots, allowing the packet stream to adapt to changing traffic conditions and capacity requirements, thereby improving infrastructure utilization while maintaining reliable TDM frame transmission
Solution Approach 2:
The patent changes the parameter of packet stream rate from a fixed value to a variable that depends on the number of allocated TDM slots. By calculating the packet rate as (number of allocated slots / total slots) × maximum packet rate, the system optimizes bandwidth usage according to actual capacity requirements, resolving the contradiction between transmission reliability and infrastructure efficiency
2Reliability
If Forward Error Correction (FEC) is applied to protect TDM frames over packet networks, then packet loss can be recovered, but the buffering delay increases significantly, especially at high packet rates
Solution Approach 1:
The patent applies partial action by implementing FEC selectively based on the actual number of allocated TDM slots. Rather than always applying maximum FEC redundancy, the system adjusts the level of error correction based on traffic conditions and capacity usage, reducing unnecessary buffering delay while maintaining adequate packet loss recovery capability for the actual traffic load
3Productivity
If the packet rate is increased to support higher TDM frame rates, then more TDM slots can be allocated, but the infrastructure cost and capacity requirements increase proportionally
Solution Approach 1:
The patent changes the relationship between packet rate and TDM slot allocation by making the packet rate variable rather than fixed. The system calculates the required packet rate based on the actual number of allocated slots, allowing high-capacity infrastructure to be efficiently utilized at lower rates when fewer slots are needed, thereby reducing infrastructure costs while maintaining the capability to support higher capacities when required
Data Source
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AI summary
There is provided a compression method for TDM frames transported over a packet network. The method is based on mapping of allocated TDM slots but not all un-allocated slots into a transport structure, which thereby reduces the needed amount of data transported over packets and hence reduces the required packet rate and packet capacity during transport of the TDM frame. The mapping is further arranged to allow dynamic changes of packet rate and packet capacity, thus the mapping is performed such that a working size of the transport TDM frame is allowed to increase or decrease over time. Further, mechanisms to lower experienced delay for low-rate signals are provided.