## 1 Introduction  
In the Industrial Internet of Things (IIoT) network, hundreds of ultra-low power, resource-constrained smart, and self-configured sensor nodes interact with each other over a short distance [1]. These interoperable nodes are equipped for manufacturing, processing, and monitoring tasks in the industrial automation sectors, such as the automobile industry, oil industry, waste management, forestry fire prevention, and others. The IEEE 802.15.4e Time Slotted Channel Hopping (TSCH) Medium Access Control (MAC), an enhancement over basic IEEE 802.15.4, was the key technology for low-power multi-hop Wireless Sensor Network (WSN) applications [2]. However, the harsh environmental conditions in the industry pose significant challenges in wireless communication, demanding robust and predictable performance. Latency, battery lifetime [3], Packet Delivery Ratio (PDR), throughput, and reliability serve as significant performance indicators for ensuring seamless communication under high traffic loads and external noise. Productivity and safety are the main objectives in IIoT networks that need strict resource provisions, as compared to consumer IoT [4]. To address these challenges in IIoT, several industrial communication protocols are being proposed. These protocols enable time synchronization by segmenting the slotframe into time slots and reducing external interference through channel hopping.  
They have demonstrated the ability to maintain Quality of Service (QoS) in networks while ensuring ultra-low power consumption.  
Devices within a TSCH network rely on a shared communication schedule, typically represented as a matrix where each cell corresponds to a unique coordinate defined by a specific time offset and channel offset. The matrix row represents channel offsets, and the column represents time offsets as shown in Figure 1. It uses the channel hopping mechanism to reduce the interference and multipath fading effect. The timeslot duration is made to be sufficiently long to allow the transmission of a packet to a neighboring node and the reception of its acknowledgment. Figure 1 also shows the basic slotframe structure for Enhanced Beacon (EB) and application data.  
The operational channel frequency \(f_{channel}\) for communication is determined from the channel offset as  
\[f_{channel}\ =(ASN+channelOffset)\ \%\ c_{nn} \tag{1}\]  
where \(ASN\) is the Absolute Slot Number, and \(c_{nn}\) is a number of channel offsets used. A limitation of the IEEE 802.15.4e TSCH standard is that it does not comprise rules for creating and managing the schedule in WSNs. Various standardization groups are developing innovative solutions to integrate industrial automation with Internet services. They standardize an architecture for the IIoT, allowing every device in the industry to  
Figure 1: TSCH schedule and slotframe structure for RPL control message, enhanced beacon transmission, and application data illustrating time and channel offsets.  
interact globally. This paper introduces a novel Adaptive and Autonomous Schedule (AAS) for 6 TiSCH networks, which dynamically adjusts transmit/receive (Tx/Rx) cells based on traffic demands and link PDR. The cell locations are determined using the MAC addresses of the sender and receiver nodes, along with their hop distances from the root. Additionally, the slotframe segment size is adapted according to the node count at a specific hop distance. This approach significantly reduces end-to-end latency, improves PDR, and extends network lifetime. The rest of the paper is organized as follows: Section 2 discusses the background, Section 3 explores the related work, Section 4 introduces the proposed scheduling algorithm, Section 5 focuses on the analytical model, performance evaluation is discussed in Section 6, and the paper is concluded in Section 7.