Enhanced CCX Protocol for RTLS Power and Accuracy
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Solution Overview
Problem
Conventional Wi-Fi-based Real-Time Location Systems (RTLS) face challenges with high power consumption and limited positional accuracy, particularly when used in conjunction with secondary technologies like infrared, low-frequency RF, or ultrasound, due to the lack of a backward channel in one-directional communication protocols such as CCX.
Innovation Solution
The enhanced CCX (ECCX) protocol introduces a message field for requesting an acknowledgment signal from Wi-Fi access points, enabling a single-directional communication system with a transmitter module in active RFID tags to request acknowledgments, which include time references, communication channel identifications, and secondary technology usages, thereby allowing for improved power management and positional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If one-directional communication protocol (CCX) is used, then power consumption is reduced, but positional accuracy is limited due to lack of back channel
Solution Approach 1:
The patent introduces an acknowledgment mechanism where access points send acknowledgment signals back to tags in response to range request messages. This feedback channel enables the tag to receive information about its detected access points and signal strengths, allowing for more accurate location calculation while maintaining low power consumption through selective communication.
Solution Approach 2:
The system dynamically adjusts communication based on tag needs. Tags can request acknowledgments when location updates are needed, and access points selectively respond based on current conditions. This dynamic approach allows the system to achieve high positional accuracy only when necessary, rather than maintaining continuous bidirectional communication.
2Measurement precision
If standard Wi-Fi bi-directional communication is used, then positional accuracy can be improved through back channel, but power consumption increases significantly
Solution Approach 1:
Instead of implementing full bi-directional communication, the patent implements partial back-channel functionality through selective acknowledgment messages. Tags receive location-related information from access points without establishing full bidirectional communication protocols, IP addresses, or association mechanisms, achieving sufficient accuracy with minimal power overhead.
Solution Approach 2:
The access point acts as an intermediary that provides necessary feedback information to tags without requiring full bidirectional communication. The acknowledgment messages serve as a mediated channel that delivers location-relevant data (detected APs, signal strengths) without establishing direct tag-to-tag or full tag-to-server communication paths.
3Loss of information
If association and IP addressing are implemented for back channel communication, then network information can be transmitted, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts only the essential feedback functionality needed for location accuracy from full Wi-Fi bidirectional communication. Rather than implementing complete association, IP addressing, and TCP/IP stacks, the system uses simplified acknowledgment messages that carry only the necessary location-related information (detected access points, signal strength indicators).
Solution Approach 2:
The acknowledgment mechanism uses lightweight, temporary communication objects rather than persistent network connections. Each acknowledgment message is a self-contained, short-lived data structure that provides necessary information without requiring ongoing protocol maintenance, IP address management, or association state tracking.
Data Source
AI summary
A wireless active RFID tag, system and method, the system including: a plurality of access points, wherein each access point is groupable by a characteristic in common with another access point; a system controller communicatively coupled to a system memory and to the plurality of access points; and an active RFID tag, the tag comprising: a transmitter module configured to transmit, to access points in the system, request for an acknowledgement from any member of a predetermined group of access points. The acknowledgement may further include one or more of a time reference used by the system; and an identification of secondary technologies used by the system.