Personal Area Network Channel Offset Scheduling
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Solution Overview
Problem
Time-slotted channel hopping (TSCH) networks face challenges in managing collisions and packet losses due to finite channels and timeslots, especially when multiple personal area networks (PANs) operate in close proximity, and existing schedules are inflexible to adapt to changing node functions or traffic requirements.
Innovation Solution
The system manages multiple PANs by allowing each network to establish a communications schedule with offset channels and synchronized timeslots, enabling nodes to adjust communication modes based on quality-of-service and traffic requirements, and allowing new networks to form by selecting unscheduled cells from existing schedules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PANs operate in close proximity using common channels and timeslots, then network coverage and node connectivity are improved, but collisions and packet losses increase
Solution Approach 1:
The patent segments the communication resources by introducing offset values that divide the channel-timeslot space into distinct regions for different PANs. Each PAN is assigned a unique offset that segments its communications from other PANs, preventing collisions while maintaining coverage.
Solution Approach 2:
The patent adds a new dimension to the communication scheduling by introducing an offset parameter that operates alongside channels and timeslots. This dimensional addition allows multiple PANs to coexist in the same physical space without interference, as each PAN occupies a unique position in the offset dimension.
2Ease of operation
If communications schedules are rigidly defined for PAN nodes, then scheduling simplicity and implementation ease are improved, but adaptability to changing node functions or traffic requirements deteriorates
Solution Approach 1:
The patent transforms the static communications schedule into a dynamic system by introducing offset values that can be adjusted based on network conditions, node functions, and traffic requirements. This allows the schedule to adapt while maintaining the structured framework of channels and timeslots.
Solution Approach 2:
The patent enables schedule flexibility by allowing changes to the offset parameter, which modifies the timing relationship between different PANs. This parameter change mechanism allows the network to adapt to varying requirements without redesigning the entire communication schedule.
3Quantity of substance
If the number of channels and timeslots is increased to support more nodes, then network capacity and node limit are improved, but system complexity and resource requirements worsen
Solution Approach 1:
Instead of increasing the number of channels and timeslots, the patent introduces offset values as an additional dimension for distinguishing between PANs. This allows more nodes to be supported without proportionally increasing channel-timeslot resources, as the offset dimension provides additional separation capability.
Data Source
AI summary
Two or more personal area networks (or PANs) operating channel hopping schedules may be operated within a vicinity of one another with channel hopping schedules according to IEEE 802.15.4 that are separated by a frequency offset, and collisions between data transmitted by the respective devices of the networks may be avoided. Nodes of a first PAN transmit beacons identifying information regarding a first communications schedule. A node of a second PAN receives the beacon and establishes a second channel hopping schedule at the offset from the first communications schedule. Nodes of PANs may be programmed with communication modes that vary uplink or downlink slots based on quality-of-service or traffic requirements.