Wireless System Frequency Hopping for Range and Power
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Solution Overview
Problem
Existing wireless systems face challenges in providing secure, long-range, high-mobility, and near-full connectivity with low power consumption and cost, while maintaining acceptable latency and avoiding excessive heat dissipation and battery size.
Innovation Solution
A low complexity, constant envelope modulation system with synchronized time slot frequency hopping, antenna diversity, and frequency diversity, using short packets and a slotted time frame structure with contention-access and allocated time slots, along with power-saving features and dynamic clock calibration, to achieve extended range and reduced latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If transmit power is increased to extend communication range, then range is improved, but power consumption and heat dissipation increase
Solution Approach 1:
The system employs periodic frequency hopping where transmitters switch between multiple frequency channels in a synchronized manner. This periodic frequency switching allows the signal to propagate over longer distances by exploiting frequency diversity, achieving extended range without requiring continuous high power transmission on a single frequency.
Solution Approach 2:
The system dynamically changes transmission parameters including frequency selection, time slot allocation, and power levels based on channel conditions and network state. By adapting these parameters periodically and in response to feedback, the system achieves long-range communication at lower average power consumption compared to fixed high-power transmission.
2Length of stationary object
If data rate is reduced to extend range, then range is improved, but system latency increases
Solution Approach 1:
The system segments data transmission into short packets distributed across multiple frequency hops and time slots. This segmentation allows data to be transmitted in smaller units that can be quickly sent and acknowledged, reducing the time penalty associated with lower data rates while maintaining extended range through the frequency hopping mechanism.
Solution Approach 2:
The system performs preliminary synchronization and frequency hopping pattern establishment before data transmission begins. Mobile nodes acquire synchronization information from beacon signals in advance, allowing them to immediately participate in frequency-hopped data transmission without delay, thus maintaining low latency despite reduced individual data rate.
3Reliability
If continuous network connection is used to maintain connectivity, then connectivity is improved, but power consumption increases
Solution Approach 1:
The system uses periodic beacon signals transmitted at scheduled intervals to maintain network connectivity. Mobile nodes can enter sleep modes between beacon intervals, waking only to receive beacons and transmit data when necessary. This periodic operation maintains network awareness and connectivity while dramatically reducing average power consumption compared to continuous monitoring.
Solution Approach 2:
The system enables mobile nodes to autonomously synchronize to frequency hopping patterns and maintain network connectivity through self-organizing mechanisms. Nodes independently acquire synchronization from beacons and automatically participate in frequency-hopped communication, eliminating the need for continuous centralized control and reducing overall network power requirements.
4Reliability
If security features are added to protect against unauthorized access, then security is improved, but device complexity and cost increase
Solution Approach 1:
The system combines security authentication with the existing frequency hopping and synchronization mechanisms. Security credentials are integrated into the beacon processing and frequency acquisition procedures, allowing authentication to occur alongside routine network operations without requiring separate complex security subsystems in each device.
Data Source
AI summary
The present invention provides a method and system for establishing a highly mobile, long range secure wireless network with dynamic topologies and near full connectivity with acceptable latency using low cost, low power, compact and lightweight devices. One aspect of the system deals with a highly mobile network with dynamic network topologies and a time varying wireless medium that has neither absolute nor readily observable boundaries outside of which radio nodes are known to be unable to receive network frames, although the desirable open field boundary is 1 mile in radius from a base station node. A synchronous frequency hopping technique is used with mobile nodes that can become slave base station nodes to a master base station node to increase the effective range of the master base station without increasing the transmit power. Furthermore, the use of adjustable sleep times for the mobile nodes, as well as a novel clock calibration method, provides a substantial range increase with acceptable battery size and system latency.