Minkoo Kang

Frame Packing for Minimizing the Bandwidth Consumption of the FlexRay Static Segment

The FlexRay protocol has emerged as the de facto standard for automotive communication systems, and it offers the advantages of both the event-triggered and time-triggered paradigms. To minimize bandwidth consumption (BC) in the static segment of the FlexRay communication cycle, we propose a frame-packing algorithm called BC minimizing with various periodic signals (BCMVPS), which is formulated as generalized integer linear programming that allows the packing of signals with different periods into a message frame. We also present the lower and upper bounds of the size of a static slot, as well as present a heuristic called BC best fit decreasing for linear frame selection for reducing the computing time of the BCMVPS algorithm. We compare the performance of the proposed algorithms with existing algorithms using the Society of Automotive Engineers benchmark data and GNU linear programming kit. The experimental results show that the BC of the proposed algorithms is less than that of the existing frame-packing algorithms.

A static message scheduling algorithm for reducing FlexRay network utilization

Currently, in order to meet customer requirements about safety and convenience, many electronics and software are used in automobiles. Because high amount of data from each electronics and software needs to be communicated fast and correctly, performance evaluation of in-vehicle network is necessary. FlexRay protocol that is suggested to guarantee exact operation of in-vehicle subsystem such as x-by-wire application has emerged as de-facto standard. However, there are only a few researches about response time analysis and timing performance verification. In this paper, to reduce FlexRay network utilization, a scheduling algorithm that long static message is assigned to dynamic segment is presented. We define system model for the algorithm and carry out performance evaluation using SAE benchmark data. Though the evaluation, we show that network utilization in all transmission speed is reduced, and also in lower transmission speed, it is reduced much more.

Determining the Size of a Static Segment and Analyzing the Utilization of In-vehicle FlexRay Network

In order to meet customer needs (e.g. safety, convenience) in current automotive industry, lots of electronics and software are deployed into vehicles, and this has led to many researches about In-vehicle network. FlexRay is a kind of In-vehicle network protocols and it will likely become de facto standard. However, to be used in vehicles successfully, the response time analysis of a FlexRay message is needed. In this paper, based on frame format, physical transmission rule and payload length, the actual length of FlexRay message frame is calculated, and we also determine the length of static slot in a communication cycle. Finally, the equation of network utilization in static segment is derived.

A scheduling algorithm for reducing FlexRay message response time using empty minislots in dynamic segment

FlexRay communication protocol that is suggested to guarantee exact operation of in-vehicle subsystem such as x-by-wire application has emerged as de-facto standard. However, there are only a few researches about response time analysis and timing performance verification for FlexRay. In this paper, to reduce message response time of FlexRay, a scheduling algorithm that long static message is assigned to dynamic segment is presented. SAE benchmark data is used for performance evaluation of proposed algorithm. Through the evaluation, we show that network utilization in all transmission speed is reduced, and also in lower transmission speed, it is reduced much more. And also, the worst-case response time of message frames that are reassigned from static segment into dynamic segment is reduced.

Mechanism for Minimizing Stuffing-bit in CAN Messages

In spite of wide acceptance of controller area network (CAN) in industrial factory automation, limited bandwidth and nondeterministic response time have restricted the wider use of CAN in safety-critical real time systems. In this paper, a mechanism for minimizing stuffing-bit is proposed to reduce the length of CAN messages for the purpose of mitigating the affects of these problems. With this mechanism, it is observed that the message length is considerably reduced and the average bandwidth utilization is increased at the same time.

Minimizing the bandwidth consumption of the FlexRay dynamic segment

To minimize bandwidth consumption in the dynamic segment of the FlexRay communication systems, a frame packing algorithm that allows the packing of signals with different periods into a message frame is proposed. The performance of the proposed algorithms with existing algorithms is evaluated using the SAE benchmark data and GNU linear programming kit. The experimental results show that the bandwidth consumption of the proposed algorithms is less than that of existing frame packing algorithms.

PDO packing mechanism for minimizing CANopen network utilization

CANopen was developed in order to resolve the hardware dependency problem of the CAN-based application. Using a concept called profiling in CANopen, it is allowed that different types of devices can interoperate with each other, which leads to the reduction of the development time for CAN-based application. The utilization of CANopen network needs to be minimized in the context of the communication performance. In order to minimize network utilization, messages need to be packed as many as possible so that message frame overhead can decrease. In this paper, a PDO packing mechanism using object dictionary (OD) and process data object (PDO) communication service in CANopen is presented. We also evaluate the performance of the mechanism with SAE benchmark data, and finally, it is seen that the network utilization of CANopen decreased by about 10% when comparing to the result in [9,10].

Advanced Bit Stuffing Mechanism for Reducing CAN Message Response Time

As customer requirements for safety and convenience in automobiles increases, so does the quantity of electronics and software installed in them. The amount of signal data from the electronics systems needs to be managed, making the design of communication protocols for in-vehicle networks (IVN) more important (Navet et al., 2005). The IVN protocols can be classified into two paradigms: event-triggered and time-triggered (Obermaisser, 2004). The event-triggered protocols are efficient in terms of network utilization, because the messages transmitted within event-triggered protocols are only transmitted when specific events occur. This differs from time-triggered communication in that the response time of message transmission is not predictable (Fabian & Wolfgang, 2006).