Jean-Baptiste Dore

CSMA/CA with RTS-CTS overhead reduction for M2M communication

Machine to machine communication (M2M) or machine type communication (MTC) facilitates communication without any human intervention. These applications will support an enormous number of stations (STAs). To mitigate degradation of the throughput and delay performance in wireless local area networks (WLAN) that employ carrier sense multiple access collision avoidance (CSMA/CA) protocol with request to send and clear to send (RTS/CTS) mechanism, we propose to reduce the overhead introduced by the hand shake mechanism. The medium access control (MAC) overhead caused by the RTS and CTS messages is high comparing to the total duration of successful transmission. In order to reduce the MAC overhead we propose in this work a new strategy to serve many users successively. This strategy consists on sending many RTS in parallel by different stations on different frequency sub-bands. Once the RTS messages do not collide with each other, there will be no need to resend the RTS and wait for a CTS to gain the channel access. In this paper, this proposed strategy is investigated and we demonstrate that it reaches better saturation throughput and delay especially in loaded networks.

Multiband CSMA/CA with RTS-CTS strategy

We present in this paper a new medium access control (MAC) scheme devoted to orthogonal frequency division multiple access (OFDMA) systems which aims at reducing collision probabilities during the channel request period. The proposed MAC relies on the classical carrier sense multiple access/collision avoidance (CSMA/CA) protocol with RTS / CTS (“Request To Send” / “Clear To Send”) mechanism. The proposed method focus on the collision probability of RTS messages exploiting a multi-channel configuration for these messages while using the whole band for data transmissions. The protocol may be interpreted as an asynchronous frequency multiplexing of RTS messages. This method achieves strong performance gains in terms of throughput and latency especially in crowded networks.

Performance Evaluation of Multiband CSMA/CA with RTS/CTS for M2M Communication with Finite Retransmission Strategy

Abstract M2xa0M communication is information exchange between machines and machines without any human interaction. M2xa0M communication based on cellular network suffers from the extremely large number of devices in service coverage. In cellular network case, the large number of devices lead to communication problem caused by collisions between the senders. In this work we study the collision probability, saturation throughput and packet error rate for the carrier sense multiple access collision avoidance (CSMA/CA) protocol with request to send and clear to send (RTS/CTS) mechanism in the case of frequency band division. We propose in this paper a modified version of CSMA/CA-RTS/CTS to be compatible with the band repartition technique and we prove that an important gain is introduced in terms of system performance especially for loaded networks. Different backoff stage numbers with different finite retransmission limit values are investigated. Simulations highlight that dividing the RTS band into independent channels reduces drastically the RTS collision probability and in particular the packet error rate. A gain in terms of saturation throughput is also demonstrated especially in charged networks mode.

MLSE detector for beyond VHBR contactless air interface

We investigate the problem of sequence detection in a non linear channel for a contactless air interface. The work presented in this study is based on the the VHBR (Very High Bit-Rate) amendments of the ISO 14443 international standard. We focused more particularly on the part of the standard extension that defines the phase modulation (PSK) from the Proximity Coupling Device (PCD) to the Passive Inductive Coupled Card (PICC). We propose an efficient detector to overcome both Inter Symbol Interference (ISI) due to the high data rates, and system non linearities introduced by the differential detection at the receiver side. The proposed detector is an adaptation of the Viterbi algorithm for constraint-ternary alphabet. Our numerical results show that a rate of 13.56 Mbps can be achieved using a 15-states sequence detector.

IEEE 1900.7 standard for white space dynamic spectrum access radio systems

Various measurements and studies have shown that some licensed frequency bands are underutilized at certain times and in certain locations. In particular, TV bands have been shown to have unused spectrum. Such observations have triggered strong interest in white space dynamic spectrum access among researchers, wireless equipment manufacturers, and standards development organizations. The IEEE Standards Committee on Dynamic Spectrum Access Networks created the White Space Radio Working Group in June 2011 to develop the IEEE 1900.7 standard for white space dynamic spectrum access radio systems. The standard was published in February 2016. This article gives an overview of key concepts and technologies of the IEEE 1900.7 standard, including use cases and requirements, the physical layer, and the MAC sublayer.

CSMA/CA Bottleneck Remediation in Saturation Mode with New Backoff Strategy

Many modern wireless networks integrate carrier sense multiple access/collision avoidance (CSMA/CA) with exponential backoff as medium access control (MAC) technique. In order to decrease the MAC overhead and the collision probability, we propose in this paper a new backoff strategy leading to better saturation throughput and access delay performance comparing to the classical protocol. We investigate the CSMA/CA with RTS/CTS technique, and we show that our strategy reaches better saturation throughput and access delay especially in dense networks. This proposed strategy distributes users over all the backoff stages to solve the bottleneck problem present in the first backoff stage. Finally, we analyze our strategy and we compare it to the classical one modeled by Markov chain. Analytical and simulation results show the improvment in term of saturation throughput. Cumulative density function (CDF) of the access delay illustrates the important gain obtained by the proposed strategy.

IEEE 1900.7 Standard for White Space Dynamic Spectrum Access Radio Systems

Various measurements and studies have shown that some licensed frequency bands are underutilized at certain times and in certain locations. In particular, TV bands have been shown to have unused spectrum. Such observations have triggered strong interest in white space dynamic spectrum access among researchers, wireless equipment manufacturers, and standards development organizations. The IEEE Standards Committee on Dynamic Spectrum Access Networks has created the White Space Radio Working Group in June 2011 to develop the IEEE 1900.7 standard for white space dynamic spectrum access radio systems. The draft of this standard is now finalized and ready for review by a broad audience during the sponsor ballot procedure. This paper gives an overview of key concepts and technologies of the draft standard P1900.7, including its use cases and requirements, its physical layer and MAC sub-layer.