Analysis of Transmission Methods for Ultra-Reliable Communications

Fifth generation of cellular systems is expected to widely enable machine-type communications (MTC). The envisioned applications and services for MTC have diverse requirements which are not fully supported with current wireless systems. Ultra-reliable communications (URC) with low-latency is an essential feature for mission-critical applications, such asindustrial automation, public safety, and vehicular safety applications. This feature guarantees a communication service with a high level of reliability. This paper investigates the feasibility and efficiency of URC over wireless links. It also analyzes the effectiveness of different transmission methods, including spatial diversity and support of hybrid automatic repeat request (HARQ). Finally, the importance of reliable feedback information is highlighted.Peer reviewe

Delay Analysis of Network Architectures for Machine-to-Machine Communications in LTE System

Machine-to-machine communications has emerged to provide autonomic communications for a wide variety of intelligentservices and applications. Among different communication technologies available for connecting machines, cellular-basedsystems have gained more attention as backhaul networks due to ubiquitous coverage and mobility support. The diverse ranges of service requirements as well as machine constraints require adopting different network architectures. This paper reviews three M2M network architectures to integrate machines into the LTE system and analyzes their associated communication delays. It also presents how the appropriate networks can be selected for some machine-to-machine applications, fulfilling their latency constraints.Peer reviewe

Data Aggregation in Capillary Networks for Machine-to-Machine Communications

As machine-to-machine applications using cellular systems become pervasive, it is an important concern that their deployment does not jeopardize the performance of the cellular systems. Support for a massive number of machines brings technical challenges affecting the performance of the random access channel and efficiency of radio resource allocation. Capillary networks are considered as an extensions to the cellular systems for providing large-scale connectivity. This paper proposes an aggregation scheme for capillary networks connected to the LTE network to improve their communication efficiency. A gateway, an intermediate unit between machines and the base station, aggregates packets from the machines during a predefined time, and then delivers them to the LTE network. In addition, this paper analyzes the trade-offs between random access interaction, resource allocation, and communication latency. Results reveals that accepting the extra latency for accumulating packets can significantly reduce the random access requests and the required resources for the data transmissions.Peer reviewe

Machine-type communications: current status and future perspectives toward 5G systems

Machine-type communications (MTC) enables a broad range of applications from mission- critical services to massive deployment of autonomous devices. To spread these applications widely, cellular systems are considered as a potential candidate to provide connectivity for MTC devices. The ubiquitous deployment of these systems reduces network installation cost and provides mobility support. However, based on the service functions, there are key challenges that currently hinder the broad use of cellular systems for MTC. This article provides a clear mapping between the main MTC service requirements and their associated challenges. The goal is to develop a comprehensive understanding of these challenges and the potential solutions. This study presents, in part, a roadmap from the current cellular technologies toward fully MTC-capable 5G mobile systems.Peer reviewe

Esiprosessoriohjelmiston järjestelmäalustan suunnittelu Nokian DX 200-järjestelmään

Nokian DX 200-keskusjärjestelmä on suuri ja monimutkainen järjestelmä. Tästä johtuen jokaisen yksikön koko ohjelmiston suunnittelu, päivitys ja ohjelmien testaus erikseen vie paljon aikaa. Ohjelmisto ei myöskään ole modulaarinen, ja projektin kulut kasvavat. Yksi tapa ratkaista nämä ongelmat ja yhtenäistää suunnittelua on luoda yhtenäinen ohjelmiston järjestelmäalusta (platform). Yksiköiden tehtävät voidaan jakaa kahteen pääkategoriaan, ts. yleisiin tehtäviin ja sovelluskohtaisiin tehtäviin. Järjestelmäalustan ohjelmisto suunnitellaan yleisiä tehtäviä varten ja sovelluskohtaiset tehtävät lisätään järjestelmäalustaan. DX 200 järjestelmän prosessoriyksikössä on käytössä ohjelmiston järjestelmäalusta, mutta tämän työn tarkoitus on esitellä tekijän suunnittelema ja toteuttama esiprosessorin järjestelmäalusta, jota käytetään eri pistoyksiköissä. Näiden pistoyksiköiden prosessori kuuluu Intelin 186-perheeseen. Esiprosessori on mikroprosessoriin perustuva liitäntäyksikkö, joka prosessorin asemesta hoitaa tiukasti reaaliaikaisen datan perusprosessoinnin. Esiprosessorin järjestelmäalusta sisältää useita suuria ohjelmalohkoja tehtävien suorittamiseksi, ja tämä työ keskittyy yhteen niistä, nimittäin muistin valvontaohjelmalohkoon. Työssä tarkastellaan muistimalleja, yleisiä muistivikoja ja useita vikojen havaitsemiseen käytettäviä algoritmeja. Lopuksi esitellään tekijän suunnittelema järjestelmäalustan muistinvalvontaohjelmalohko, joka ottaa huomioon kyseiset muistimallit ja -viat

Link adaptation design for ultra-reliable communications

The fifth generation (5G) of cellular networks is expected to provide connectivity for a wide range of services. This requires the network to encounter novel features. Ultra-reliable communications (URC) is one of the considered features, which provides a certain level of communication service almost all the time. This is essential in order to support mission-critical applications, such as industrial automation, public safety, and vehicular communications. This paper studies link adaptation optimization for URC, considering errors in both data and feedback channels. As the implementation of optimal link adaptation is challenging, particularly, for downlink transmissions due to the limited feedback channel, a simple link adaption scheme is also proposed. Results reveal that the performances of the proposed and optimal link adaptation schemes are close. Hence, the proposed scheme can be utilized to efficiently support URC in cellular networks.Peer reviewe