Branched Communications Network Using CDMA for IoT Sensor Data
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Solution Overview
Problem
IoT sensor networks face challenges in efficient data transmission due to limited power resources, interference, and data collision issues, particularly in wireless communication, where sensors with minimal processing power need to minimize power usage and maximize data efficiency while avoiding collisions.
Innovation Solution
The implementation of Code Division Multiple Access (CDMA) technology with spread-spectrum encoding sequences allows for simultaneous data transmission from multiple sensors using unique codes, enabling efficient duplex communication within a limited duty cycle, reducing power consumption, and enhancing security by aggregating data through intermediate elements in a hierarchical network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sensors transmit data using wireless media in transmit/receive state, then data transmission capability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic transmission cycles where sensors alternate between active transmit/receive states and sleep states. Each transmission cycle is time-bound and repetitive, allowing sensors to maximize data transmission during active periods while conserving energy during sleep periods, directly resolving the contradiction between transmission capability and power consumption
Solution Approach 2:
The system dynamically adjusts the duration and frequency of transmit/receive states based on network conditions, data priority, and power availability. Transmission parameters are not fixed but adapt in real-time, allowing optimization of both data transmission efficiency and power consumption according to changing operational requirements
2Adaptability or versatility
If sensors operate in idle state to detect transmissions, then data reception capability is improved, but power consumption remains high
Solution Approach 1:
Sensors periodically switch between idle detection states and sleep states based on transmission cycles. During designated reception windows, sensors activate to detect and process transmissions; between these windows, they enter low-power sleep mode. This periodic activation pattern enables adequate data reception capability while dramatically reducing average power consumption compared to continuous idle operation
Solution Approach 2:
Sensors autonomously manage their own power states based on pre-configured transmission schedules and detected network activity patterns. The system self-regulates by entering sleep mode when no transmissions are expected and automatically waking for scheduled reception periods, eliminating the need for continuous high-power idle operation while maintaining reception capability
3Productivity
If multiple sensors transmit data simultaneously using the same frequency, then network efficiency is improved, but data collision and interference increase
Solution Approach 1:
The patent segments the transmission medium by assigning unique spread-spectrum codes to different sensors, creating orthogonal communication channels. Instead of dividing time or frequency slots, the system segments the code space, allowing simultaneous transmissions from multiple sensors to be mathematically separated at the receiver through correlation with the assigned codes, thereby enabling high network efficiency without data collisions
Solution Approach 2:
The system changes the fundamental parameter used for multiple access from time/frequency division to code division. By transforming the identification parameter from temporal or spectral characteristics to unique spreading codes, the system enables simultaneous transmissions to coexist without interference, as each sensor's signal is modulated by a distinct code that can be independently decoded at the receiver
4Reliability
If duty cycle is restricted to prevent interference, then network reliability is improved, but transmission time is reduced
Solution Approach 1:
The patent changes the fundamental approach to interference prevention from temporal duty cycle restriction to spatial code separation. Instead of limiting transmission time windows to avoid collisions, the system uses unique spread-spectrum codes to allow simultaneous transmissions. This parameter transformation from time-based to code-based separation eliminates the need for restrictive duty cycles while maintaining interference prevention through the orthogonal properties of the spreading codes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces power consumption, increases network efficiency, and enhances security by allowing multiple sensors to transmit data simultaneously, achieving faster communication and minimizing data collisions, with the potential to support a large number of sensors while maintaining data integrity.
Implementation Method 1
each signal including a spread spectrum encoding sequence specific to the device convolved with encoded data relating to the device
Data Source
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AI summary
A spread spectrum system is used for transmitting data to and from devices operable as sensors and actuators in a distributed system. Communication is made through a series of aggregation nodes in a branched hierarchical network. Each device and aggregation node has a respective spread spectrum code, and has a corresponding encoder/decoder (401, 402...., 252, 352, 452, 552.) in a central control system 4 operating the same spread spectrum codes, the encoded data relating to the devices being aggregated over a shared channel. At each level in the hierarchy the aggregated signals to/from the next level are recoded. This allows the same codes (153, 253), to be re-used at different levels, and in different sub-branches in the same level, increasing the number of devices that can be served on one channel.