Distributed TDMA MAC Protocol for Wireless Body Area Network Synchronization
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Solution Overview
Problem
In Wireless Body Area Networks (WBAN), existing MAC protocols like CSMA and TDMA face challenges in high contention environments, leading to increased collisions, unpredictable delays, and high overhead due to time synchronization, making them unsuitable for real-time responses in scenarios with multiple piconets in close proximity.
Innovation Solution
A distributed TDMA MAC protocol that converges CSMA and TDMA, allowing nodes to operate independently with mobility and interference avoidance by exchanging control messages, eliminating the need for a single time reference for synchronization, and adjusting data transmission times based on received time division schedule advertisement messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TDMA is used for time synchronization in WBAN, then channel utilization ratio is improved and collisions are reduced, but overhead increases due to time synchronization requirements
Solution Approach 1:
The patent extracts the time synchronization function from the central coordinator and distributes it to all piconet nodes. Each node maintains its own time reference and performs autonomous synchronization, eliminating the overhead of centralized time synchronization management while maintaining TDMA's collision reduction benefits
Solution Approach 2:
Each piconet node serves itself by maintaining local time references and performing autonomous time synchronization. Nodes independently adjust their transmission schedules based on received schedule advertisement messages from other piconets, eliminating dependency on a central time synchronization authority and reducing overall system overhead
2Productivity
If CSMA is used in WBAN, then channel utilization ratio is high in low contention environment, but performance deteriorates due to increased collisions in high contention environment
Solution Approach 1:
The patent segments the WBAN into multiple independent piconets, each operating with its own time division schedule. This segmentation isolates collision domains, allowing CSMA to operate effectively within each piconet while TDMA coordination between piconets prevents inter-piconet collisions, thus maintaining high channel utilization without performance deterioration
Solution Approach 2:
The patent implements dynamic time schedule adjustment where piconets can modify their transmission schedules based on detected interference from neighboring piconets. This dynamic adaptation allows the system to maintain high channel utilization by avoiding collisions through real-time schedule adjustments rather than static allocation
3Loss of time
If a single time reference is used for synchronization in TDMA, then time synchronization is achieved, but overhead increases when nodes enter new piconets or move
Solution Approach 1:
Each node maintains its own time reference and performs autonomous synchronization with the new piconet by receiving and processing schedule advertisement messages. This self-service approach eliminates the need for centralized time reference establishment and reduces overhead during node movement or piconet entry
Solution Approach 2:
The system uses pre-established time division schedules and schedule advertisement messages that contain timing information. When nodes join new piconets or move, they can immediately use the pre-formatted schedule information from received messages to synchronize without requiring time-consuming reference establishment procedures
Data Source
AI summary
Short range wireless communication is provided. A first node included in a Wireless Body Area Network (WBAN) communicates with at least one neighboring second node. The first node transmits or receives data to or from at least one device node connected to the first node during a time division communication period, using a super-frame in which the time division communication period, a time division schedule advertisement message transmission period, and a Contention Access Period (CAP) are sequentially arranged. The first node broadcasts a time division schedule advertisement message of the first node to the at least one second node during the time division schedule advertisement message transmission period within the super-frame. Upon receiving a time division schedule advertisement message from the second node during the CAP within the super-frame, the first node adjusts a data transmission or reception time for the at least one device node connected to the first node using the received time division schedule advertisement message.