Dmitry Akhmetov

A Directional CSMA/CA Protocol for mmWave Wireless PANs

In this paper, we investigate the problem of medium access control in mmWave wireless personal area networks (WPAN), within which directional antennas are used to combat the high path loss incurred in the 60GHz frequency band. The conventional CSMA/CA protocol does not work well with directional antennas due to impaired carrier sensing at the transmitters. We explain why existing directional MAC protocols do not work well at 60GHz and propose a novel directional CSMA/CA protocol designed specifically for 60GHz WPANs. Instead of relying on physical carrier sensing, the proposed protocol adopts virtual carrier sensing and relies on a central coordinator to distribute network allocation vector (NAV) information. Both performance analysis and simulation study show that the proposed mechanism incurs low overhead and has robust performance even when the network is heavily congested.

Ieee 802.11ad: introduction and performance evaluation of the first multi-gbps wifi technology

Multi-Gbps communication is the next frontier in high-speed local and personal wireless technologies, which will offer the necessary foundation for a new wave of applications such as wireless display, high-speed device synchronization, and the evolution of Wi-Fi. The wide harmonized spectrum in the unlicensed millimeter-wave (60 GHz) band is considered the most prominent candidate to support the evolution towards multi-Gbps data rates. As such, the industry is in the process of defining new 60 GHz PHY and MAC technologies that can serve a wide variety of applications and usages, as to avoid the proliferation of non-coexistent devices operating in this unoccupied spectrum. The most promising activity is taking place under the auspices of the IEEE 802.11ad task group, which is defining amendments to the 802.11 standard for operation in the 60GHz band. In this paper we describe the main components of the MAC and PHY amendments included in the current IEEE 802.11ad draft standard and that enable multi-Gbps data rates. We also provide a comprehensive set of simulation results for typical use cases, and argue that 802.11ad is poised to be the standard that will enable mass market adoption of multi-Gbps wireless communication in the 60 GHz spectrum band.

Directional CSMA/CA Protocol with Spatial Reuse for mmWave Wireless Networks

In recent years, the millimeter wave (mmWave) technology has gained considerable interest due to the huge unlicensed bandwidth (i.e., up to 7GHz) available in the 60GHz band in most part of world. In this paper, we investigate the problem of medium access control (MAC) in mmWave wireless networks, within which directional antennas are used to combat the high path loss incurred in the 60GHz band. We extend a directional CSMA/CA protocol presented in our prior work by exploiting spatial reuse. The proposed protocol adopts virtual carrier sensing and allows non-interfering links to communicate simultaneously. We present a performance analysis as well as simulations to evaluate the proposed protocol. Our results show that the directional MAC with spatial reuse can achieve considerable performance improvements over the 802.11 MAC and the protocol proposed in our prior work. It introduces low protocol overhead and has robust performance even when the network is heavily congested.

Multi-User Operation in mmWave Wireless Networks

In this paper, we investigate the problem of multi-user spatial division multiple access (MU SDMA) operation in mmWave wireless networks, within which directional antennas are used to combat the high path loss incurred in the 60GHz band. We study the feasibility of MU SDMA in mmWave networks and propose two MAC protocols to support CSMA/CA based uplink and downlink MU SDMA transmissions. The proposed protocols adopt virtual carrier sensing and allows multiple users to communicate with an access point (AP) simultaneously. Performance analysis and simulation results both show that the proposed protocols can achieve considerable performance improvements over a system that supports only single user (SU) operation.

802.11N: Performance Results of Reverse Direction Data Flow

This article explores the value of reverse direction data flow feature of the emerging IEEE 802.11n WLAN standard. It discusses usage cases for the reverse direction data flow feature, shows the performance benefit of its use and explains how this benefit arises

RF Concurrency Performance Study for Integrated WiFi Radio

We investigate issues associated with integrated radio design. Multiple constraints (e.g., due to interference or component sharing) may prohibit integrated radios from operating at the same time instance. We examine constraints defined by integrated radio RF concurrency capability, and study WiFi performance under different radio RF concurrency levels. We performed detailed simulation study for WiFi/WiMAX integrated radios. The insight obtained from our study can help evaluate the tradeoff between integrated radio design and performance of associated networks.

Support of high-performance i/o protocols over mmWave networks

In this paper, we present a cross-layer framework for support of high performance I/O protocols over mmWave networks. We define an architecture that supports the unique requirements imposed by I/O protocols, in which a protocol adaptation layer is introduced between the mmWave radio and the I/O protocol stack. The adaptation layer on the control plane manages the wireless I/O connection; on the data plane, it translates the short I/O data frames into a custom mmWave data exchange protocol that efficiently utilizes the wireless resources. The proposed architecture hides the wireless medium from the I/O protocol such that the existing I/O stack remains unchanged and can be reused in devices equipped with mmWave radio.