NB-IoT Uplink Synchronization for Satellite Networks
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Solution Overview
Problem
The challenge lies in adapting narrowband Internet of Things (NB-IoT) technology for non-terrestrial networks, particularly satellite communication, where high transmission delay and large path loss complicate synchronization and data transmission, leading to increased power consumption and overheads due to the need for ephemeris delivery and synchronization.
Innovation Solution
A narrowband internet of things-based communication method and apparatus that employs a frame structure with a synchronization sequence and data frame within a superframe, where the synchronization sequence is formed by repeating sequences, allowing the terminal device to send uplink signals without needing a synchronization signal from the network device, enabling asynchronous communication and reducing synchronization overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional NB-IoT synchronization method is used in satellite communication, then synchronization can be achieved, but transmission overheads increase due to ephemeris delivery and synchronization signals
Solution Approach 1:
The patent extracts and removes the ephemeris delivery and synchronization signal transmission from the satellite-to-terminal communication process. Instead, the terminal device autonomously generates synchronization sequences based on a predefined frame structure, eliminating the need for the network device to deliver ephemeris or send synchronization signals, thus reducing transmission overheads while maintaining synchronization capability
Solution Approach 2:
The terminal device performs self-synchronization by autonomously generating synchronization sequences using a predefined frame structure and sequence generation algorithm. The terminal device independently completes synchronization without relying on synchronization signals or ephemeris delivery from the network device, reducing both transmission overheads and power consumption
2Measurement precision
If synchronization is performed before data transmission in satellite communication, then synchronization accuracy is improved, but time overheads and power consumption increase
Solution Approach 1:
The patent applies preliminary action by pre-defining the frame structure and synchronization sequence generation algorithm in the terminal device before communication begins. The terminal device can immediately generate synchronized uplink signals upon receiving the downlink signal without requiring a separate synchronization phase, thereby reducing time overheads while maintaining synchronization accuracy through the predefined structure
Solution Approach 2:
The terminal device autonomously performs synchronization by generating synchronization sequences based on the predefined frame structure, eliminating the need for network-delivered synchronization signals. This self-service approach reduces both time overheads and power consumption associated with traditional synchronization procedures
3Adaptability or versatility
If NB-IoT is used in satellite communication, then communication functionality is achieved, but power consumption increases due to synchronization and decoding operations
Solution Approach 1:
The patent extracts and removes the power-consuming synchronization signal reception and ephemeris decoding operations from the terminal device. By using autonomous synchronization sequence generation with a predefined frame structure, the terminal device avoids expensive decoding operations while maintaining communication functionality, thereby significantly reducing power consumption
Solution Approach 2:
The terminal device performs self-synchronization through autonomous sequence generation based on predefined parameters, eliminating the need for power-intensive synchronization signal processing and ephemeris decoding. This self-service mechanism maintains full communication functionality while dramatically reducing power consumption in satellite communication environments
4Measurement precision
If ephemeris delivery is performed in satellite communication, then positioning accuracy is improved, but transmission overheads and time delays increase
Solution Approach 1:
The patent extracts and removes the ephemeris delivery process from the communication system. The terminal device achieves positioning and synchronization functionality through autonomous sequence generation using predefined frame structures, eliminating the need for network-delivered ephemeris data and associated transmission overheads
Solution Approach 2:
The terminal device independently determines its synchronization parameters and positioning information through autonomous sequence generation based on predefined algorithms, without relying on ephemeris delivery from the network. This self-service approach eliminates transmission overheads and time delays associated with ephemeris delivery while maintaining positioning accuracy
Data Source
AI summary
This application discloses a NB-IoT-based communication method and an apparatus, to evolve a NB-IoT communication technology into an NTN. The method is as follows: A terminal device generates an uplink signal, including a superframe which includes a synchronization sequence located in first duration of the superframe and a data frame located in second duration which is after the first duration, the synchronization sequence successively includes a first sequence repeated Ni times and a second sequence repeated N2 times, the second sequence is obtained by multiplying the first sequence by −1, a part of consecutive sequences of the synchronization sequence are used as a first synchronization reference sequence that is obtained based on the second sequence repeated N2 times and one or more first sequences that are sorted from back to front in the first sequence repeated N1 times. The terminal device sends the uplink signal to a network device.