ECTS: Enhanced Centralized TSCH Scheduling with Packet Aggregation for Industrial IoT

The Industrial Internet of Things (IoT) has gained a lot of momentum thanks to the introduction of Time Slotted Channel Hopping (TSCH) in IEEE 802.15.4. At last, we can enjoy collision-free, low-latency wireless communication in challenging environments. Nevertheless, the fixed size of time slots in TSCH provides an opportunity for further enhancements. In this paper, we propose an enhanced centralized TSCH scheduling (ECTS) algorithm with simple packet aggregation while collecting data over a tree topology. Having in mind that the payload of a sensor node is rather short, we attempt to put more than one payload in one packet. Thus, we occupy just one cell to forward them. We investigated the schedule compactness of ECTS in Matlab, and we evaluated its operation, after implementing it in Contiki-NG, using Cooja. Our results show that ECTS with packet aggregation outperforms TASA in terms of slotframe duration and imposes fairness among the nodes in terms of latency. A validation exercise using real motes confirms its successful operation in real deployments.

ECTS: Enhanced Centralized TSCH Scheduling with Packet Aggregation for Industrial IoT

The Industrial Internet of Things (IoT) has gained a lot of momentum thanks to the introduction of Time Slotted Channel Hopping (TSCH) in IEEE 802.15.4. At last, we can enjoy collision-free, low-latency wireless communication in challenging environments. Nevertheless, the fixed size of time slots in TSCH provides an opportunity for further enhancements. In this paper, we propose an enhanced centralized TSCH scheduling (ECTS) algorithm with simple packet aggregation while collecting data over a tree topology. Having in mind that the payload of a sensor node is rather short, we attempt to put more than one payload in one packet. Thus, we occupy just one cell to forward them. We investigated the schedule compactness of ECTS in Matlab, and we evaluated its operation, after implementing it in Contiki-NG, using Cooja. Our results show that ECTS with packet aggregation outperforms TASA in terms of slotframe duration and imposes fairness among the nodes in terms of latency. A validation exercise using real motes confirms its successful operation in real deployments.

Performance Analysis of Packet Aggregation Mechanisms and Their Applications in Access (e.g., IoT, 4G/5G), Core, and Data Centre Networks

The transmission of massive amounts of small packets generated by access networks through high-speed Internet core networks to other access networks or cloud computing data centres has introduced several challenges such as poor throughput, underutilisation of network resources, and higher energy consumption. Therefore, it is essential to develop strategies to deal with these challenges. One of them is to aggregate smaller packets into a larger payload packet, and these groups of aggregated packets will share the same header, hence increasing throughput, improved resource utilisation, and reduction in energy consumption. This paper presents a review of packet aggregation applications in access networks (e.g., IoT and 4G/5G mobile networks), optical core networks, and cloud computing data centre networks. Then we propose new analytical models based on diffusion approximation for the evaluation of the performance of packet aggregation mechanisms. We demonstrate the use of measured traffic from real networks to evaluate the performance of packet aggregation mechanisms analytically. The use of diffusion approximation allows us to consider time-dependent queueing models with general interarrival and service time distributions. Therefore these models are more general than others presented till now.

A Novel Packet Aggregation Mechanism for Enhancing VoIP Performance on IEEE 802.11 Wireless Mesh Networks

In 802.11 Wireless Mesh Network (WMN), bandwidth will be wasted much for transferring VoIP flows since each voice frame must contain relatively large amount of protocol data. “Packet Aggregation” mechanism can be applied to merge the voice data of multiple VoIP flows into one frame for transmission. It reduces the waste on bandwidth and increases the maximum number of successful VoIP calls. In addition, the mechanism “MCF controlled channel access” (MCCA) defined in 802.11 standard can be used to obtain better QoS than adopting default EDCA mechanism. In MCCA, mesh stations which wants to transfer VoIP flows can reserve time intervals of the medium for transmission and this reservation will be advertised to their neighbors. It is why MCCA causes less medium contentions than EDCA. In this paper, a mechanism to transfer VoIP flows in IEEE 802.11 WMN by MCCA with packet aggregation scheme is proposed. The effectiveness of the proposed mechanism is shown by simulation results. In addition, the problem named as Routing-Packet Aggregation / De-aggregation-Scheduling optimization problem (abbr. RPADS problem) derived from the proposed mechanism is also studied. A heuristic algorithm for RPADS problem to maximize the total number of supported calls is also proposed.