A Scalable Hybrid MAC Protocol for Massive M2M Networks

In Machine to Machine (M2M) networks, a robust Medium Access Control (MAC) protocol is crucial to enable numerous machine-type devices to concurrently access the channel. Most literatures focus on developing simplex (reservation or contention based)MAC protocols which cannot provide a scalable solution for M2M networks with large number of devices. In this paper, a frame-based Hybrid MAC scheme, which consists of a contention period and a transmission period, is proposed for M2M networks. In the proposed scheme, the devices firstly contend the transmission opportunities during the contention period, only the successful devices will be assigned a time slot for transmission during the transmission period. To balance the tradeoff between the contention and transmission period in each frame, an optimization problem is formulated to maximize the system throughput by finding the optimal contending probability during contention period and optimal number of devices that can transmit during transmission period. A practical hybrid MAC protocol is designed to implement the proposed scheme. The analytical and simulation results demonstrate the effectiveness of the proposed Hybrid MAC protocol

Medium Access Control Protocol for High Altitude Platform Based Massive Machine Type Communication: -

Massive Machine Type Communication (mMTC) can be used to connect a large number of sensors over a wide coverage area. One of the places where mMTC can be applied is in wireless sensor networks (WSNs). A WSN consists of several sensor nodes that send their sensing information to the cluster head (CH), which can then be forwarded to a high altitude platform (HAP) station. Sensing information can be sent by the sensor nodes at the same time through the same medium, which means collision can occur. When this happens, the sensor node must re-send the sensing information, which causes energy wastage in the WSN. In this paper, we propose a Medium Access Control (MAC) protocol to control access from several sensor nodes during data transmission to avoid collision. The sensor nodes send Round Robin, Interrupt and Query data every eight hours. The initial slot for transmission of the Round Robin data can be either randomized or reserved. Analysis performance was done to see the efficiency of the network with the proposed MAC protocol. Based on the series of simulations that was conducted, the proposed MAC protocol can support a WSN system-based HAP for monitoring every eight  hours. The proposed MAC protocol with an initial slot that is reserved for transmission of Round Robin data has greater network efficiency than a randomized slot

Medium Access Control Protocol for High Altitude Platform Based Massive Machine Type Communication: -

Massive Machine Type Communication (mMTC) can be used to connect a large number of sensors over a wide coverage area. One of the places where mMTC can be applied is in wireless sensor networks (WSNs). A WSN consists of several sensor nodes that send their sensing information to the cluster head (CH), which can then be forwarded to a high altitude platform (HAP) station. Sensing information can be sent by the sensor nodes at the same time through the same medium, which means collision can occur. When this happens, the sensor node must re-send the sensing information, which causes energy wastage in the WSN. In this paper, we propose a Medium Access Control (MAC) protocol to control access from several sensor nodes during data transmission to avoid collision. The sensor nodes send Round Robin, Interrupt and Query data every eight hours. The initial slot for transmission of the Round Robin data can be either randomized or reserved. Analysis performance was done to see the efficiency of the network with the proposed MAC protocol. Based on the series of simulations that was conducted, the proposed MAC protocol can support a WSN system-based HAP for monitoring every eight  hours. The proposed MAC protocol with an initial slot that is reserved for transmission of Round Robin data has greater network efficiency than a randomized slot

Integración de redes de sensores en las nuevas generaciones de sistemas de comunicaciones móviles 4G y 5G

El concepto actual de Internet de las Cosas (Internet of Things, IoT) y la tendencia hacia la utilización masiva de redes basadas en sensores plantea la duda de cómo va a ser posible transportar la información proveniente de dichas redes de una forma factible y eficiente. Una opción prometedora es la utilización de la red móvil celular existente (LTE/LTE-A). La realidad es que esta última no puede soportar una inclusión masiva de nodos sin afectar a los usuarios. Actualmente hay una gran actividad de investigación y estandarización tanto para adaptar las próximas versiones de las tecnologías actuales, como en la definición de la próxima generación de sistemas móviles, 5G, en la que resolver esta problemática resulta un punto clave. En las redes móviles actuales, la limitación viene más por un problema de saturación de los canales de señalización que de capacidad de la red. En el presente trabajo investigamos los aspectos de señalización del estándar de comunicaciones Long Term Evolution (LTE) para su posible uso conjunto con la red de sensores en versiones futuras y en la próxima generación. Creemos que una red de sensores con un gran número de nodos, que requiera poco uso de datos, puede interferir con los usuarios. Esto es debido a que pueden colapsar los canales de control y, por lo tanto, provocar un retraso general para todos los terminales de la red. Encontramos que efectivamente se produce este problema en el canal PUCCH, que es el principal canal de control del enlace ascendente. En este canal se asigna un recurso a cada terminal para peticiones de transmisión, por lo que al aumentar el número de terminales, el retraso aumenta proporcionalmente. Después de analizar diferentes investigaciones realizadas sobre la integración de sensores en LTE y comunicaciones tipo máquina, proponemos un modelo basado en una de ellas. Se trata de un modelo del canal de acceso aleatorio (RACH), donde los sensores realicen sus peticiones de transmisión en ese canal en vez de en el PUCCH. Sobre dicho modelo proponemos diversas modificaciones para mejorar el rendimiento y conseguir que no afecte a los usuarios que usen ese canal, como por ejemplo, la separación de los recursos del canal de acceso aleatorio (RACH) entre usuarios y sensores. Finalmente comprobamos que el modelo cumple con los objetivos mediante una simulación de tiempo discreto. Explicamos la estructura de la simulación detalladamente y verificamos los resultados mediante gráficas.The actual concept of Internet of Things (IoT) and the trend towards the massive use of sensor based networks bring up the question of how it will be possible to transport the information from these networks in a feasible and efficient way. A promising choice is using the current mobile cellular network (LTE/LTE-A). But the reality is that it can’t support a massive inclusion of nodes without affecting the users. There is currently a very active research and standardization for both adapting the next versions of the current technologies and defining the next generation of mobile systems, 5G, in which solve this problem is a key factor. In the existing mobile networks, the limitation is more a saturation problem of the signalling channels than network’s capacity. In this project we investigate the signalling aspects of 3GPP Long Term Evolution (LTE) for its possible use with the sensor network in future versions and next generation. We believe that a sensor network with a large number of nodes with low data traffic can interfere with the users due to saturation of the control channels, and, therefore, causing a general delay in all the terminals of the network. We found that, indeed, this problem occurred in the PUCCH channel, which is the main uplink control channel. In this channel it is assigned a resource to each terminal for transmission requests, hence when the number of terminals is increased, the delay increases on a proportional way. Afterwards, we make an overview about the different investigations realized concerning the sensors integration on LTE and machine type communications. Then, we propose a model based on one of them. It is random access channel (RACH) model, where the sensors use that channel to perform transmission requests instead of the PUCCH. We propose some modifications to improve the performance and to attain that it does not affect the users using that channel, like, for example, a division of the random access channel (RACH) resources between users and sensors. Finally, we prove, with a discrete time simulation, that the model fulfil the objectives. We explain the simulation structure in detail and we verify the results using graphics.Ingeniería de Sistemas de Comunicacione

Lightly synchronized Multipacket Reception in Machine-Type Communications Networks

Machine Type Communication (MTC) applications were designed to monitor and control elements of our surroundings and environment. MTC applications have a different set of requirements compared to the traditional communication devices, with Machine to Machine (M2M) data being mostly short, asynchronous, bursty and sometimes requiring end-to-end delays below 1ms. With the growth of MTC, the new generation of mobile communications has to be able to present different types of services with very different requirements, i.e. the same network has to be capable of "supplying" connection to the user that just wants to download a video or use social media, allowing at the same time MTC that has completely different requirements, without deteriorating both experiences. The challenges associated to the implementation of MTC require disruptive changes at the Physical (PHY) and Medium Access Control (MAC) layers, that lead to a better use of the spectrum available. The orthogonality and synchronization requirements of the PHY layer of current Long Term Evolution Advanced (LTE-A) radio access network (based on glsofdm and Single Carrier Frequency Domain Equalization (SC-FDE)) are obstacles for this new 5th Generation (5G) architecture. Generalized Frequency Division Multiplexing (GFDM) and other modulation techniques were proposed as candidates for the 5G PHY layer, however they also suffer from visible degradation when the transmitter and receiver are not synchronized, leading to a poor performance when collisions occur in an asynchronous MAC layer. This dissertation addresses the requirements of M2M traffic at the MAC layer applying multipacket reception (MPR) techniques to handle the bursty nature of the traffic and synchronization tones and optimized back-off approaches to reduce the delay. It proposes a new MAC protocol and analyses its performance analytically considering an SC-FDE modulation. The models are validated using a system level cross-layer simulator developed in MATLAB, which implements the MAC protocol and applies PHY layer performance models. The results show that the MAC’s latency depends mainly on the number of users and the load of each user, and can be controlled using these two parameters

Modelling of a Hybrid MAC Protocol for M2M Communications

Machine-to-machine (M2M) communications is one of the enabling technologies for connecting massive number of devices to the Internet of Things (IoT). M2M communications have different characteristics than human-to-human (H2H) communications. In this work, we propose a scalable, hybrid MAC protocol that will satisfy user quality-of-service (QoS) requirements. We model both periodic and nonperiodic traffic. The proposed MAC protocol organizes transmissions into superframes consisting of a number of frames. A machine is assumed to generate a one or zero packet per its period. The machines have been divided into several types according to their packet generation probabilities. The generated packets are classified into different traffic classes according to their tolerance to packet losses and served by a subframe. Further, each subframe is divided into two sub-periods one serving contention and the other reserved traffic of that traffic class. We formulated an optimization problem that minimizes frame length subject to QoS user requirements. Then, we derived packet loss probability for each class as well as total packet loss probability for the optimization. Formulation resulted in a nonlinear optimization problem, but numerical results show that an LP approximation provides a nearly optimal solution. The work also considered the proposed protocol under user mobility. The packet arrival process under user mobility has been derived. Then the performance of the protocol has been evaluated with the contention service under this arrival process. The contention service with and without packet losses have been considered. A priority queueing mechanism also has been studied for M2M communication. The results of this thesis may be useful in the design of M2M communication system