4D-TDMA Multi-User Transmission for Flexible Satellite Resource Allocation
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Solution Overview
Problem
Current satellite communication systems in the X/Ka bands lack flexibility and data protection, are not compatible with low bitrates, and require complex planning, leading to sub-optimal resource allocation and service disruptions.
Innovation Solution
A 4D-TDMA multiuser transmission method that dynamically adjusts the number and type of carriers, frequency bands, and coding/modulation schemes based on terminal needs, allowing for flexible resource allocation and data protection by sharing transmission channels and using orthogonal frequency hopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional MF-TDMA systems use fixed carrier allocation, then system planning is simplified, but resource allocation becomes sub-optimal and spectral efficiency decreases
Solution Approach 1:
The system dynamically adapts the number of carriers and their allocation based on the actual number of active terminals and service requirements. The network controller continuously monitors terminal activity and adjusts carrier configuration in real-time, transforming the static carrier allocation into a dynamic resource management system that optimizes spectral efficiency while accommodating varying network conditions
Solution Approach 2:
The system changes key parameters including the number of carriers, carrier frequencies, and terminal-carrier assignments based on network conditions. By varying these parameters dynamically rather than fixing them, the system achieves optimal resource allocation for different network states without requiring completely different system configurations
2Reliability
If the number of carriers is increased to handle more terminals, then service continuity is improved, but spectral efficiency decreases due to under-utilization when few terminals are active
Solution Approach 1:
The system dynamically adjusts the number of active carriers based on the number of terminals requiring service. When few terminals are active, fewer carriers are allocated, maximizing spectral efficiency. When more terminals require service, the system activates additional carriers to maintain service continuity, thus adapting resource allocation to actual demand in real-time
3Adaptability or versatility
If conventional systems use fixed coding/modulation schemes, then implementation is simplified, but adaptability to varying terminal needs and propagation conditions is reduced
Solution Approach 1:
The system implements a universal modem capable of supporting multiple coding and modulation schemes within a single device. This multi-functional modem can adaptively select and switch between different ModCod schemes based on service requirements and propagation conditions, eliminating the need for separate specialized modems for each scheme while maintaining full adaptability
4Reliability
If existing X/Ku/Ka band systems are used without frequency hopping, then system simplicity is maintained, but data protection and interference resistance are insufficient
Solution Approach 1:
The system implements periodic frequency hopping where carriers systematically change frequencies according to a predetermined pattern. This periodic frequency variation provides data protection against interference and jamming while maintaining relatively simple system architecture through algorithmic frequency management rather than complex hardware modifications
Data Source
AI summary
A method and a system for multi-user transmission in a network, comprising at least on network control center NCC and one or more terminals, wherein the method comprises at least the following steps: determining the number of 4D-TDMA carriers as a function of the number and needs of the terminals, determining the type (SCPC or TDMA) and frequency band Bi of each of the 4D-TDMA carriers as a function of the terminals transmitting on the carriers, for each frame, dividing the band B into PTDMA transmission channels and into PSCPC service channels, each channel consisting of frames comprising a plurality of slots, STDMA slots and SSCPC slots, dynamically allocating a plurality of slots of a 4D-TDMA carrier according to the services required by each terminal, configuring the coding and modulation scheme of each slot by taking account of the quality of the received signals.