The IEEE 802.11ah, also known as WiFi HaLow, is a scalable solution for medium-range communication in Internet of Things (IoT). While provisioning support for the IoT and machine-to-machine (M2M) communication, IEEE 802.11ah leverages various innovative medium access control (MAC) layer concepts, such as restricted access window (RAW), hierarchical association identification (AID), traffic indication map (TIM) segmentation, etc. This article presents a survey on various MAC protocols for IEEE 802.11ah. While discussing the essential features of IEEE 802.11ah, this survey points out various issues and limitations of such MAC protocols. Although there are some surveys available for MAC protocols of IEEE 802.11ah, they do not include a large number of schemes that have been recently proposed to solve different standardization and implementation-based issues. This article individually surveys issues and challenges in the different problem domains of the IEEE 802.11ah MAC protocol and analyzes the recently proposed solutions. Moreover, this article identifies various factors for further improvement of these protocols. Compared to other relevant surveys, this article emphasizes the issues and challenges to enable researchers to easily identify the problem domain.

IPv6 over Low power Wireless Personal Area Network (6LoWPAN) has been widely used for large-scale sensing and actuating purposes in Internet of Things (IoT). Though promising, many challenges like high latency, heterogeneity, and packet loss persist. To mitigate these challenges, Software-Defined Network (SDN) technique can be hybridized with existing IoT structures that can address many of them. In this paper, we proposed an approach – Edge-based 6LoWPAN-SDN (6LE-SDN) architecture, which can improve the system limitations mentioned. It uses an edge-based computational capability to improve the network performance over 6LoWPAN. To reduce heterogeneity, we develop a hybrid-edge switch that helps to enable communication among 6LoWPAN and SDN entities. For efficient communication between different devices, a new protocol— Edge-based 6LoWPAN-SDN Protocol (6LE-SDNP) is proposed, which is capable of ensuring optimal routing of the packet for efficient communication among the devices. We use SDN based edge-controller for reducing latency of the network apart from improving the interoperability feature. The testbed evaluation of the proposed solution indicates satisfactory performance in terms of reducing latency by 60% and network overhead by 91%. The 6LE-SDN network also succeeded in reducing the average round trip time (RTT) by 31% and the packet loss by 70% as compared to that of the traditional 6LoWPAN-based IoT.

Internet of Things (IoT) with edge computing capability enhances efficiency, availability, and improves latency of an industrial automation system. However, to provide dynamic services at the resource-constrained edge device, reconfiguration of services is necessary. This article proposes a programmable edge network to (re)configure different services of industrial IoT, that employs programmable layers at the edge for reconfiguring the sensor/actuator network and application services. The lowermost layer allows reconfiguring the communication-related parameters and the middle layer consists of a software-defined networking (SDN) controller that can dynamically program different modules and handles actuation decisions from the edge. An interfacing protocol between the layers is proposed to provide reliability by considering the required configuration parameters among layers. At the top layer, a priority forwarding mechanism is designed for SDN core (control loop) communication when sensor and actuator are on different edges. The proposed architecture significantly improves the actuation latency and is highly energy efficient compared to the existing state-of-the-art.