Carl Bergenhem

Fibre-ribbon ring network with inherent support for earliest deadline first message scheduling

This paper presents a network with earliest deadline first (EDF) scheduling on a per slot basis. The network is called CCR-EDF (Control Channel based Ring network with EDF scheduling). The topology is a pipelined unidirectional fibre-ribbon ring that supports several simultaneous transmissions in non-overlapping segments and with dedicated fibres for clock and arbitration. In each slot the node that has highest priority generates the clock. The clock hand over strategy together with the scheduling feature gives the network the functionality for earliest deadline scheduling of periodic messages belonging to logical real-time connections. Logical realtime connections may be added and removed during runtime, through admission control. Guaranteed realtime communication service is supported to the user. Other services include best effort traffic and special services for parallel and distributed processing such as barrier synchronisation and global reduction.

Fibre-ribbon pipeline ring network with distributed global deadline scheduling and deterministic user services

This paper introduces a novel, fair medium access protocol for a pipelined optical ring network. The protocol provides global deadline scheduling of packets. Requests for sending packets are sent by the nodes in the network to a master node. The master uses the deadline information in the requests to determine which packet is most urgent. Arbitration is done in two steps, the collection and distribution phases. The protocol is therefore called two-cycle medium access (TCMA). The network is best suited for LANs and SANs (system area networks) such as a high speed network in a cluster of computers or in an embedded parallel computer. Offered services in this network include best effort messages, guarantee seeking messages, real-time virtual channels, functions used in parallel processing. These are possible without additional higher level protocols. A simulation analysis of the network with the protocol is presented. Further analysis shows minimum slot length and fairness of the protocol.

Curvature based antenna selection method evaluated using the data age metric and V2V measurements

In this paper, we compare a method for selecting transmission antenna based on road curvature to a method based on periodically alternating between left and right hand side transmission antennas. Both methods aim to improve the success rate for communication between participants in a platoon of vehicles. Moreover, we propose the data age metric for online use as input to the algorithm controlling the inter-vehicle distance in platooning, e.g. to decide appropriate gap between the vehicles depending on the V2V communication quality. The methods have been evaluated through V2V communication measurements performed using heavy duty vehicles on public highway. We show that, when using the curvature-based method, a 150 ms data age deadline is only missed approximately half as often compared to when periodically alternating between left and right hand side transmission antennas. The methods have also been compared for different antenna combinations.

Architecting cars as constituents of a system of systems

Future transportation systems will be a heterogeneous mix of items with varying connectivity and interoperability. A mix of new technologies and legacy systems will co-exist to realize a variety of scenarios involving not only connected cars but also road infrastructures, pedestrians, cyclists, etc. Future transportation systems can be seen as a System of Systems (SoS), where each constituent system - one of the units that compose an SoS - can act as a standalone system, but the cooperation among the constituent systems enables new emerging and promising scenarios. In this paper we investigate how to architect cars so that they can be constituents of future transportation systems. This work is realized in the context of two Swedish projects coordinated by Volvo Cars and involving some universities and research centers in Sweden and many suppliers of the OEM, including Autoliv, Arccore, Combitech, Cybercom, Knowit, Prevas, ÅF-Technology, Semcom, and Qamcom.