TSCH MAC Redundancy Cell Allocation for Wireless Scheduling
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Solution Overview
Problem
Current scheduling methods for Time Slotted Channel Hopping Medium Access Control (TSCH) and IEEE 802.15.4e networks fail to optimize schedules for varying latency demands, link reliability, and traffic demands, leading to increased latency, reduced throughput, and inefficient power usage due to lack of redundancy in communication links.
Innovation Solution
A network device allocates redundancy cells to links based on traffic demand and link reliability, allowing for retransmissions during designated redundancy cells without interfering with primary schedule transmissions, thereby minimizing delays and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy cells are allocated to links for retransmissions, then communication reliability is improved, but device complexity and schedule management complexity increase
Solution Approach 1:
The patent pre-allocates redundancy cells during schedule construction based on link quality metrics and traffic demands. By performing this allocation in advance rather than dynamically during operation, the system establishes reliability safeguards beforehand while maintaining manageable schedule complexity through systematic pre-planning
Solution Approach 2:
The patent applies different levels of redundancy allocation to different links based on their specific characteristics. Links with poorer quality or higher traffic demands receive more redundancy cells, while better links receive fewer, creating a differentiated approach that improves overall reliability without uniformly increasing complexity across all links
2Reliability
If more redundancy cells are allocated for retransmissions, then packet delivery reliability improves, but loss of time increases due to additional retransmission opportunities
Solution Approach 1:
The patent pre-allocates specific time slots as redundancy cells during schedule construction, placing them at strategically optimal positions in the schedule. This preliminary placement ensures that retransmissions can occur with minimal delay by having pre-designated slots ready, rather than waiting for the next available opportunity
Solution Approach 2:
The patent optimizes the timing and positioning of redundancy cells by adjusting schedule parameters during construction. By changing when and where redundancy opportunities are placed in the schedule based on traffic patterns and link characteristics, the system minimizes the time penalty associated with having retransmission capabilities
3Productivity
If redundancy cells are allocated based on traffic demand and link reliability, then spectrum efficiency improves, but device complexity increases due to sophisticated scheduling requirements
Solution Approach 1:
The patent implements differentiated redundancy allocation where each link receives redundancy cells according to its specific traffic demand and reliability requirements. This localized optimization allows the system to concentrate spectrum resources where they are most needed, improving overall spectrum efficiency without requiring uniform complex management across all links
Solution Approach 2:
The patent uses traffic demand and link reliability metrics as input parameters to automatically determine redundancy cell allocation. By changing the scheduling approach to be parameter-driven rather than fixed, the system adapts to varying conditions and optimizes spectrum usage dynamically while the underlying algorithm maintains manageable complexity through systematic parameter-based decision-making
4Reliability
If nodes wake up for all scheduled cells to check for transmissions, then communication reliability improves, but power consumption increases
Solution Approach 1:
The patent implements a selective wake-up mechanism where nodes only activate for a subset of their scheduled cells rather than all cells. By using partial action (waking up for only some cells based on actual traffic needs), the system maintains communication reliability for active links while significantly reducing power consumption by avoiding unnecessary wake-ups during idle periods
Data Source
AI summary
A network device for a wireless local area network, specifically a TSCH MAC and IEEE 802.15.4e wireless network. The network device can wirelessly communicate with a plurality of wireless network nodes over at least one frequency channel according to a schedule which allocates cells to links. A cell is a timeslot on a frequency channel; and a link represents communication between two network nodes or a network node and the network device. The network device has a radio and a processor. The radio is operable to receive traffic information, comprising the number of packets each of the network nodes is planning to transmit during a scheduling period and the processor is configured to define a schedule. The schedule has at least one cell allocated to a link as a redundancy cell for communicating a packet when communication of a packet by the link during an earlier allocated cell fails.