A QoS-aware Scheduling with Node Grouping for IEEE 802.11ah

The recent IEEE 802.11ah amendment has proven to be suitable for supporting large-scale devices in Internet of Things (IoT). It is essential to provide a minimum level of Quality of Service (QoS) for critical applications such as industrial automaton and healthcare. In this paper, we propose a QoSaware Medium Access Control (MAC) layer solution to enhance network reliability and reduce critical traffic latency by an adaptive station grouping and a priority traffic scheduling scheme. The proposed grouping scheme calculates the current traffic load and distributes among different RAW groups considering different requirements of the stations. The RAW scheduling scheme further provides priority slot access using a novel backoff scheme. Markov-chain model is developed to study the throughput and latency behaviours for the traffic generated from the critical application. The proposed protocol shows significant delay improvement for priority traffic. The overall throughput performance improves up to 12.7% over the existing RAW grouping scheme.

Evaluasi Pengaruh Parameter TIM Berdasarkan Multirate Terhadap Konsumsi Energi Jaringan IEEE 802.11ah

WLAN IEEE 802.11ah is wireless standard technology which potentially used for IoT networking to provide longer range transmission than WPAN and LPWAN. MAC layer IEEE 802.11ah introduces TIM segmentation scheme that provides effective management toward STA in large amount to make the energy consumption efficiently. STA is organized in hierarchical structure that allows TIM segmentation to reduce the length of frame beacon contains TIM. In case there’s no segmentation in a network with many STA, the TIM would be longer and requires all STA to wake-up receiving beacon TIM including STA without downlink data. This research intends to evaluate and analyze the TIM optimal parameters. Those are Page Period, Page Slice Length and Page Slice Count toward IEEE 802.11ah energy efficiency based on multirate using simulator NS-3 implemented on IEEE 802.11ah. As the result of STA experiment shows that Non-TIM is only optimal on sleep duration while TIM is optimal on energy consumption and delay packet. In the experiment of impact of STA/Slot amount based on Page Slice Length shows that sleep duration and energy consumption is optimal depends on the amount of the STA/Slot and data rate used while the optimal packet delay varies for each Page Slice Length.

IEEE 802.11ah-Enabled Internet-of-Drone Architecture

<div>IEEE 802.11ah is considered as a promising and scalable solution for connecting a large number of drones. With the support of sub-1GHz channel bands, relay, and group-based channel access mechanism, 802.11ah can help drone stations for collecting commands, sending data, and processing response to the control room. However, achieving required throughput and latency is still challenging due to high mobility and dynamic relaying requirement. This article proposes an IEEE 802.11ahbased Internet-of-Drones (IoD) architecture for surveillance and remote control. Our scheme predicts the location of a drone and places the required association and channel access configuration to a relay node dynamically. Moreover, the current mode of a drone station is switched to relay from station as per the location. The relay nodes use transmission opportunity (TXOP) with implicit acknowledgement to increase the efficiency of the network. The performance analysis shows significant improvement in terms of throughput and latency.</div>

IEEE 802.11ah-Enabled Internet-of-Drone Architecture

<div>IEEE 802.11ah is considered as a promising and scalable solution for connecting a large number of drones. With the support of sub-1GHz channel bands, relay, and group-based channel access mechanism, 802.11ah can help drone stations for collecting commands, sending data, and processing response to the control room. However, achieving required throughput and latency is still challenging due to high mobility and dynamic relaying requirement. This article proposes an IEEE 802.11ahbased Internet-of-Drones (IoD) architecture for surveillance and remote control. Our scheme predicts the location of a drone and places the required association and channel access configuration to a relay node dynamically. Moreover, the current mode of a drone station is switched to relay from station as per the location. The relay nodes use transmission opportunity (TXOP) with implicit acknowledgement to increase the efficiency of the network. The performance analysis shows significant improvement in terms of throughput and latency.</div>

Improved ISR for IEEE 802.11ah Nonlinearity Compensation via Adjustable Constellation Borders

Iterative subcarrier regularization (ISR) has been recently proposed as a receiver-side remedy for orthogonal frequency division multiplexing (OFDM) nonlinearity. It allows the power amplifier of OFDM transmitters to operate at a lower input back-off for more efficient uplinks. However, the compensation ability cannot align with increasing channel quality, because the standard quadrature amplitude modulation (QAM) used in ISR may eliminate compensation due to erroneous decisions. To solve this issue, an improved version of ISR was proposed to flexibly adjust the constellation borders of QAM and numerically optimize it based on IEEE 802.11ah (hereinafter referred to as 802.11ah) specifications. Simulations show that the proposed scheme not only improves the converged bit error rate of ISR but also accelerates its own convergence, especially in a high channel quality, thereby achieving better power efficiency for Internet of Things clients without additional computational complexity.