Range Extension in IEEE 802.11ah Systems Through Relaying

Abstract

A great number of Internet of Things (IoT) and machine-to-machine (M2M) based applications, which are telecommunication areas with the highest foreseen growth in the future years, require energy efficient, long range and low data rate wireless communication links. In order to offer a competitive solution in these areas, IEEE 802.11 standardization group has defined the "ah" amendment, the first sub-1GHz WLAN standard, with flexible channel bandwidths, starting from 1MHz, up to 16MHz, and many other physical and link layer improvements, enabling long-range and energy efficient communications. However, for some regions, like Europe, the maximum transmitted power in dedicated frequency band is limited to only 10mW, thus disabling the achievement of ranges which would be close to targeted of up to 1km. In this paper we examine possibilities for range extension through implementation of half-duplex decode-and forward (DF) relay station (RS) in communication between an access point (AP) and an end-station (ST). Assuming a Rician fading channel between AP and RS, and a Rayleigh fading channel on the RS -ST link, we analytically derive results on achievable ranges for the most robust modulation and coding schemes (MCSs), both on downlink (DL) and uplink (UL). Analyses are performed for two different standard adopted deployment scenarios on the RS -ST link, and variable end-to-end link outage probabilities. Moreover, we have analyzed whether the considered most robust MCSs, known for supporting the longest range, but the lowest data rates, can meet the defined requirement of at least 100kb/s for the greatest attainable AP -RS -ST distances. We examine data rate enhancements, brought by coding and using of short packets, for both DL and UL. Finally, we present bit error rate (BER) results, obtained through simulations of a dual-hop DF IEEE 802.11ah relay system for the considered MCs. All presented results confirm that IEEE 802.11ah systems, through deployment of relay stations, become an interesting solution for M2M and IoT based applications, due to flexibility they offer in many aspects, meeting requirements for wide transmission ranges in such applications.Keywords -IEEE 802.11ah· decode-and-forward relay· range · data rate· BER Enis Kocan,

IEEE 802.11ah-Enabled Internet of Drone Architecture

“…The relay facility the devices to use high data rates and TXOP sharing. Kocan et al [4] examined the increased range possibility using relays in IEEE 802.11ah and implemented the communication between AP and end-user device with half-duplex decode-and-forward relay station. In [5] Kumar et al presented and implemented a hierarchical MAC scheme for efficient management and deployment of relay nodes in using NS-3 simulator.…”

Restricted Access Window-Based Resource Allocation Scheme for Performance Enhancement of IEEE 802.11ah Multi-Rate IoT Networks

“…The analysis of achievable data rate is provided in this subsection for IEEE 802.11ah multi-rate network with macro deployment scenario [33], [35]. Here, the link budget for power received at the receiver STA of data rate C x |x ∈ [1, c] can be expressed as,…”

“…The fade margin with respect to link outage is expressed as, F M = −10 log 10 (− ln(1 − P out )), where P out is the outage probability. For the required level of link-outage P out = 0.1 [35]. Furthermore, the SNR at the receiver STA is given by,…”

Increasing LPWAN Scalability by Means of Concurrent Multiband IoT Technologies: An Industry 4.0 Use Case

“…• To improve data transmission efficiency and extend range coverage, IEEE 802.11ah allows for using a dual-hop relay system in between end devices and the AP [24]. By carefully choosing the position of the relay and the AP, the expected range in DL is up to 800 m, whereas in uplink (UL) it is about 550 m [25].…”