ZCNET LPWAN Parallel Root Channels Capacity
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Solution Overview
Problem
Existing low power wide area network (LPWAN) technologies, such as LoRa, face limitations in capacity and resource efficiency, struggling to support a large number of simultaneous transmissions while maintaining high packet receiving ratios.
Innovation Solution
The Zadoff-Chu (ZC) Network (ZCNET) employs Zadoff-Chu sequences to enable multiple parallel root channels within a single frequency channel, using a simple ALOHA-style protocol for medium access, allowing nodes to randomly select transmission channels and ranges, and modulates data with a root ZC sequence, applying Forward Error Correction (FEC) and phase offset to achieve high capacity and low interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LoRa technology is used for LPWAN communication, then communication range and low power consumption are achieved, but network capacity and simultaneous transmission support are limited
Solution Approach 1:
The frequency band is divided into multiple parallel root channels (e.g., 8 root channels), each capable of supporting independent transmissions. This segmentation allows multiple nodes to transmit simultaneously on different root channels without interference, dramatically increasing network capacity from single-channel LoRa to multi-channel ZCNET operation.
Solution Approach 2:
The patent introduces a new dimension by using multiple parallel root channels in addition to traditional frequency division. Instead of only using time-division or single-frequency transmission, ZCNET adds the dimension of multiple orthogonal root channels, enabling exponential increase in simultaneous transmission capacity.
2Productivity
If more nodes are supported simultaneously, then network capacity increases, but packet receiving ratio decreases due to increased interference
Solution Approach 1:
Zadoff-Chu sequences serve as an intermediary mechanism that provides orthogonal code division multiplexing across multiple root channels. This intermediary structure allows the system to distinguish between signals from different nodes even when they transmit simultaneously on different root channels, maintaining high packet receiving ratios despite increased network density.
Solution Approach 2:
The patent changes the key parameter from single-frequency transmission to multi-frequency root channels with orthogonal ZC sequences. By changing the frequency domain parameters and adding code division, the system can support more simultaneous transmissions while maintaining signal distinguishability and packet reception reliability.
3Speed
If traditional LPWAN technologies are used, then low power consumption is achieved, but bandwidth occupancy is high and data rates are low
Solution Approach 1:
Each root channel in ZCNET can serve multiple functions: it can be used by different nodes for uplink transmissions, supports multiple modulation schemes (MCS), and can be dynamically allocated. This multi-functionality allows the system to achieve high data rates by activating multiple root channels simultaneously without requiring proportional increases in total bandwidth.
Data Source
AI summary
A novel LPWAN technology includes a ZCNET node that transmit signals that occupy a very small fraction of the signal space, resulting in very low collision probabilities. ZCNET supports parallel root channels within a single frequency channel by using Zadoff-Chu (ZC) root sequences. The root channels do not severely interfere with each other, because the interference power is spread evenly over the entire signal space. ZCNET has its node randomly choose the transmission channel and range, while still achieving high packet receiving ratios such as 0.9 or above, because the load in each root channel is small.