Хоров Евгений Михайлович

Prototyping and Experimental Study of Non-Orthogonal Multiple Access in Wi-Fi Networks

2020 · ARTICLE · en

NOMA is a promising way to increase spectral efficiency recently discussed in the IEEE 802.11 Working Group that develops WiFi standards. NOMA can be very beneficial in a WiFi network where the qualities of the channel between the access point and associated stations are significantly different. In such scenarios, NOMA allows the access point to transmit several data streams to various stations in parallel using one antenna and the same time-frequency resources. This article presents and evaluates the first-ever prototype of a WiFi device supporting NOMA, implemented in a software-defined radio platform. The prototype is backward compatible with legacy WiFi versions. Specifically, one of the multiplexed streams may be received by a legacy station not supporting NOMA. This feature is favorable for heterogeneous deployments with various generations of WiFi devices. This article provides a detailed description of the prototype as well as experimental results showing from 37 percent to 100 percent gain achieved by including NOMA in the future 802.11 standards.

Radio access network design with software-defined mobility management

2020 · ARTICLE · en

The softwarization of wireless networks has necessitated an overhaul of existing mobility management strategies. Specifically, mobility management is no longer constrained to function within the boundaries of a pre-existing radio access network. Softwarization of the network infrastructure allows resource configurations and associations to be changed on-demand, in a manner so as to support a least cost mobility management framework. To this end, this paper presents an optimal radio access network design framework augmented with user-specific clusters from the perspective of mobility management. The proposed framework is supported by a detailed mathematical model that characterizes user mobility, system traffic, and signaling costs. Performance evaluation is based on a cost comparison with conventional LTE/NR networks, and reinforces the fact that the framework proposed herein results in significant cost reduction, even in the face of changing network scenarios.

Prototyping NOMA Constellation Rotation in Wi-Fi

2020 · CHAPTER · en

Nonorthogonal Multiple Access for Servicing the Internet of Things and Web Traffic in Wi-Fi Networks

2020 · ARTICLE · en

Nowadays, many devices require a wireless Internet connection, while the available frequency spectrum is limited. The nonorthogonal multiple access (NOMA) is a multiplexing technology that can significantly improve spectral efficiency and thus solve this problem. In this paper, the use of NOMA in Wi-Fi networks with two traffic types, Web traffic and Internet of Things (IoT) traffic, is investigated. Web traffic is one of the main Internet traffic types. It consists of relatively small data flows that need to be quickly delivered to users. IoT traffic consists of very short data flows compared to Web traffic, but there can be a lot of IoT flows due to a large number of IoT devices. In this paper, we propose an algorithm for resource allocation in Wi-Fi networks with the NOMA. This algorithm takes into account the traffic of both types and its performance is investigated by simulation.

On the Joint Usage of Target Wake Time and 802.11ba Wake-Up Radio

2020 · ARTICLE · en

Energy efficiency is a significant challenge for modern wireless networking devices. It is crucial for the Internet of Things devices, is required for battery-supplied user devices such as smartphones, and is advisable for high-performance devices such as wireless VR headsets. This article examines the ability of modern Wi-Fi devices to achieve extremely low power consumption when they rarely send and receive data. Two recently developed mechanisms, namely Target Wake Time (TWT) and Wake-Up Radio (WUR), are studied. The first one allows stations to schedule the frame exchanges in advance, while the second one introduces a low-power radio for control information exchange. Although TWT and WUR differ significantly, they both suffer from the clock drift effect that significantly degrades their performance in the case of rare traffic. The paper describes these mechanisms, focusing on their revolutionary features, and presents mathematical models to evaluate the impact of this effect on TWT and WUR mechanism efficiency in terms of energy and channel time consumption. The paper also proposes and thoroughly examines various approaches to the joint and separate usage of TWT and WUR in Wi-Fi networks.

Adaptive Transmission Parameters Selection Algorithm for URLLC Traffic in Uplink

2020 · CHAPTER · en

Fast and reliable alert delivery in mission-critical Wi-Fi HaLow sensor networks

2020 · ARTICLE · en

Rapidly evolving, the Internet of Things imposes new challenges for the developers of wireless networks. Various critical infrastructure monitoring scenarios require fast and reliable alert delivery. In such systems, multiple sensors are entrusted to react to the same emergency event. Thus, it is enough to receive an alert message from any of these sensors. However, such a message shall be reliably delivered as soon as possible. The recently published Wi-Fi HaLow standard defines the Restricted Access Window (RAW) mechanism that coordinates transmissions of numerous devices. Thus, it can improve reliability and reduce delays. The paper is the first to study the usage of RAW in a scenario of emergency alerts, where the alert shall be received from at least one sensor. The paper presents an easy-to-calculate mathematical model of alert delivery with RAW. The model allows dynamic online reconfiguration of RAW parameters to select such parameters that minimize consumed channel timeshare while providing satisfactory reliability and delivery delay for an alert. Intensive performance evaluation shows that the RAW is fruitful for mission-critical data delivery in the considered scenario.

Performance evaluation of uplink NOMA in Wi-Fi networks

2020 · CHAPTER · en

© 2020 IEEE.Non-orthogonal multiple access (NOMA) is a key technology for future wireless systems. Keeping the number of antennas on the devices unchanged, NOMA increases the spectral efficiency of the wireless system and raises the aggregated system throughput. For this reason, NOMA is a very attractive technology for implementation in future Wi-Fi standards that will come after Wi-Fi 7. The paper proposes and evaluates uplink NOMA in Wi-Fi, The obtained results show approximately 100% gain in throughput of the uplink NOMA comparing with the legacy Wi-Fi systems.

A Tutorial on IEEE 802.11ax High Efficiency WLANs

2019 · ARTICLE · en

While celebrating the 21st year since the very first IEEE 802.11 “legacy” 2 Mbit/s wireless Local Area Network standard, the latest Wi-Fi newborn is today reaching the finish line, topping the remarkable speed of 10 Gbit/s. IEEE 802.11ax was launched in May 2014 with the goal of enhancing throughputper-area in high-density scenarios. The first 802.11ax draft versions, namely D1.0 and D2.0, were released at the end of 2016 and 2017. Focusing on a more mature version D3.0, in this tutorial paper, we help the reader to smoothly enter into the several major 802.11ax breakthroughs, including a brand new OFDMAbased random access approach as well as novel spatial frequency reuse techniques. In addition, this tutorial will highlight selected significant improvements (including PHY enhancements, MUMIMO extensions, power saving advances, and so on) which make this standard a very significant step forward with respect to its predecessor 802.11ac

Cloud-based Management of Energy-Efficient Dense IEEE 802.11ax Networks

2019 · CHAPTER · en

During the last decade, the number of devices connected to the Internet by Wi-Fi has grown significantly. A high density of both the client devices and the hot spots posed new challenges related to providing the desired quality of service in the current and emerging scenarios. To cope with the negative effects caused by network densification, modern Wi-Fi is becoming more and more centralized. To improve network efficiency, today many new Wi-Fi deployments are under control of management systems that optimize network parameters in a centralized manner. In the paper, for such a cloud management system, we develop an algorithm which aims at maximizing energy efficiency and also keeps fairness among clients. For that, we design an objective function and solve an optimization problem using the branch and bound approach. To evaluate the efficiency of the developed solution, we implement it in the NS-3 simulator and compare with existing solutions and legacy behavior.