Load-Balanced Sensor Grouping for IEEE 802.11ah Networks

Chang, Tung-Chun; Lin, Chi-Han; Lin, Kate Ching-Ju; Chen, Wen-Tsuen

doi:10.1109/glocom.2014.7417476

Cited by 14 publications

(23 citation statements)

References 8 publications

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“…Several algorithms focus on mitigating hidden node collisions by splitting mutually hidden nodes into orthogonal groups [ 18 , 19 , 20 ]. Additionally, Chang et al proposed a set partitioning algorithm that assumes the (static) traffic demand of each station is known by the AP and load balances them across groups [ 21 ]. Most of these recent algorithms still assume simplified homogeneous traffic [ 18 , 20 ].…”

Section: Related Workmentioning

confidence: 99%

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Real-Time Station Grouping under Dynamic Traffic for IEEE 802.11ah

Tian

Khorov

Latré

et al. 2017

Sensors

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IEEE 802.11ah, marketed as Wi-Fi HaLow, extends Wi-Fi to the sub-1 GHz spectrum. Through a number of physical layer (PHY) and media access control (MAC) optimizations, it aims to bring greatly increased range, energy-efficiency, and scalability. This makes 802.11ah the perfect candidate for providing connectivity to Internet of Things (IoT) devices. One of these new features, referred to as the Restricted Access Window (RAW), focuses on improving scalability in highly dense deployments. RAW divides stations into groups and reduces contention and collisions by only allowing channel access to one group at a time. However, the standard does not dictate how to determine the optimal RAW grouping parameters. The optimal parameters depend on the current network conditions, and it has been shown that incorrect configuration severely impacts throughput, latency and energy efficiency. In this paper, we propose a traffic-adaptive RAW optimization algorithm (TAROA) to adapt the RAW parameters in real time based on the current traffic conditions, optimized for sensor networks in which each sensor transmits packets with a certain (predictable) frequency and may change the transmission frequency over time. The TAROA algorithm is executed at each target beacon transmission time (TBTT), and it first estimates the packet transmission interval of each station only based on packet transmission information obtained by access point (AP) during the last beacon interval. Then, TAROA determines the RAW parameters and assigns stations to RAW slots based on this estimated transmission frequency. The simulation results show that, compared to enhanced distributed channel access/distributed coordination function (EDCA/DCF), the TAROA algorithm can highly improve the performance of IEEE 802.11ah dense networks in terms of throughput, especially when hidden nodes exist, although it does not always achieve better latency performance. This paper contributes with a practical approach to optimizing RAW grouping under dynamic traffic in real time, which is a major leap towards applying RAW mechanism in real-life IoT networks.

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Section: Related Workmentioning

confidence: 99%

“…Most of these recent algorithms still assume simplified homogeneous traffic [ 18 , 20 ]. However, two algorithms [ 19 , 21 ] focus on more realistic traffic, where stations have heterogeneous, static and non-saturated traffic.…”

Section: Related Workmentioning

confidence: 99%

Real-Time Station Grouping under Dynamic Traffic for IEEE 802.11ah

Tian

Khorov

Latré

et al. 2017

Sensors

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“…We assume that the network is dominated by uplink traffic, which implies that the STA is the transmitter and the AP is the receiver. 27,28 The AP implements group sectorization and divides its coverage into six equal nonoverlapping sectors. A beacon frame is transmitted at the start of each sector interval.…”

Section: System Modelmentioning

confidence: 99%

AID‐based backoff for throughput enhancement in 802.11ah networks

Nabuuma

Alsusa

Baidas

2019

Int J Communication

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Summary IEEE 802.11ah is a WiFi standard developed to address requirements associated with the heterogeneous nature of the Internet of Things. It uses the sub‐1 GHz bands to enable long‐range transmissions for low‐power devices. However, long‐range coverage exacerbates the hidden node problem. To mitigate this problem, sectorization and grouping have been proposed by the standard. In this paper, hierarchical clustering and a modified Welsh‐Powell algorithm are combined to create hidden node‐free groups in a sectorized wireless local area network. An analytical model is developed for a deterministic backoff technique that uses association identifiers to set the backoff in order to eliminate collisions. The performance of the deterministic backoff technique is compared with that of existing schemes. Our results show that this approach results in higher throughput and lower latency than other deterministic backoff techniques.

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“…Several algorithms utilize RAW to mitigate hidden node collisions by splitting mutually hidden nodes into orthogonal groups [13], [14], [15]. Chang et al proposed a set partitioning algorithm that assumes the (static) traffic demand of each station is known by the AP and load balances them across groups [16]. Other existing algorithms focus on simple partitioning metrics, such as fully random [17] or based on the back-off timer value [18], which in reality is not known to the AP.…”

Section: Related Workmentioning

confidence: 99%

IEEE 802.11ah Restricted Access Window Surrogate Model for Real-Time Station Grouping

Tian

Mehari

Santi

et al. 2018

2018 IEEE 19th International Symposium on "A World of Wireless, Mobile and Multimedia Networks" (WoWMoM)

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The Restricted Access Window (RAW) mechanism proposed by IEEE 802.11ah promises to address one of the major problems of the Internet of Things (IoT): high channel contention in large-scale densely deployed sensor networks. The RAW feature allows the Access Point (AP) to divide stations into different groups, with only the stations in the same group being allowed to access the channel simultaneously. Existing station grouping strategies only support homogeneous scenarios, where all sensor stations have the same fixed data transmission interval, modulation and coding scheme (MCS) and packet size. In this paper, we present two contributions to address this issue. First, a surrogate model that predicts RAW performance given specific network conditions and RAW configuration parameters. It is fast to train and can be solved in real-time. Second, the Model-Based RAW Optimization Algorithm (MoROA), which uses the surrogate model to determine the optimal RAW configuration in real-time, for heterogeneous stations and dynamic traffic. We compare the accuracy of our surrogate model to simulation results. Performance of MoROA is compared to existing RAW optimization algorithms and traditional 802.11 channel access methods. The results shows that the trained surrogate model can accurately predict RAW performance with a relative error less than 7% and 10% for 95% and 98% of the RAW configurations respectively. MoROA achieves a throughput up to twice as high as traditional 802.11 channel access functions in dense heterogeneous networks.

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Load-Balanced Sensor Grouping for IEEE 802.11ah Networks

Cited by 14 publications

References 8 publications

Real-Time Station Grouping under Dynamic Traffic for IEEE 802.11ah

Real-Time Station Grouping under Dynamic Traffic for IEEE 802.11ah

AID‐based backoff for throughput enhancement in 802.11ah networks

IEEE 802.11ah Restricted Access Window Surrogate Model for Real-Time Station Grouping

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