Stanislav Mudriievskyi

CSMA/CA: Improvements of the contention window adaptation

We study the Narrowband Power Line Communications (NB-PLC) system intended to be used for Smart Grid applications. The performance of such system highly depends on the implementation and the used techniques. In this paper the Medium Access Control (MAC) layer of a specific system with the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism is studied. The main feature of the used technique is that it automatically adopts the parameters of the protocol to the dynamically changing network. We investigate the protocol and suggest the improvements that give a higher performance.

Performance evaluation of MAC backoff algorithm in Narrowband PLC

This paper investigates the backoff algorithm for Narrowband Power Line Communications (PLC) Medium Access Control (MAC) protocol. Specifically, the paper considered the MAC designed by Yitran and implemented within its Differential Code Shift Keying (DCSK) technology. In this algorithm width of the contention window is calculated based on the estimated number of active nodes in the network. Further the performance of the algorithms were evaluated under different saturated throughput conditions and varying number of active nodes, in a fully meshed network. Comparison were also made between the simulated and the polynomial backoff algorithms dynamic characteristics. Simulation results show that the algorithm under investigation has an excellent performance under the saturated throughput, although its dynamic characteristic can be further improved.

DLC+VIT4IP project: High-speed NB-PLC for smart grid communication — Design of field trial

This paper covers the research activities in the framework of the European project DLC+VIT4IP. The focus of the project is the design, test and verification in the field trials of the high speed narrowband PLC systems, which should overcome the challenges and fulfill the requirements imposed by different smart grid applications; such as smart metering, SCADA, demand side managements, etc. After describing the main milestones of the project the paper gives an overview about the simulation used for the system evaluation during the development phase. We show also the current activities, which are focusing on the selection and the design of field trials. For the evaluation of the developed system on the site, a test tool and set of test procedures have been designed.

Performance evaluation of the G.hn PLC PHY layer

Simulation of the IP end-to-end communication system requires accurate models which include the layers 4 to 1 of the ISO/OSI protocol stack. Usually these models are an abstraction of the real system. In this paper we focus on the PHY layer of a G.hn [1] system over PLC and calculate its throughput with respect to the PHY layer parameters: forward error correction (FEC) block size, packet size, repetitions number, etc. The parameters setup influences the efficiency of the PLC network very much. The results show that correct parameter settings for the specific traffic and channel conditions may save either energy required for transmission or equipment costs. This gives the opportunity for efficient scheduling on the medium access (MAC) layer in terms of effective use of the transmission capacity.

Adaptive layer switching for smart grid applications in power line communications

The ongoing changes from the conventional electrical grid towards the smart grid bring new use cases to the communication technologies. These provide new applications with the different traffic requirements. The power line communications (PLC) is the most native communication technology for the smart grid as it uses the same medium for energy and data transmission. In order to meet the smart grid application requirements perfectly the corresponding PLC system should be equipped with the carefully selected medium access control (MAC) layer. Depending on the offered traffic in the network this layer may operate not optimally. Therefore in this paper we propose adaptive layer switching (ALS) on the medium access control (MAC) layer. Typically TDMA or CSMA/CA channel access scheme or a combination of both is adapted. Adaptive layer switching assesses the load of the network and switches completely the access mechanism from TDMA to CSMA/CA or otherwise. In this manner both protocols are used in the area of the network load where they have the best performance. Overall performance in term of delay-throughput tradeoff is improved as well.

Development and Calibration of a PLC Simulation Model for UPA-Compliant Networks

Communication network of the Smart Grid is intended to serve a numerous amount of applications of different types. Its complicated structure often requires a utilization of several communication technologies: wireless, cable, etc. Power line communication (PLC) also remains a challenging solution for usage in this area. The present paper is targeted to explore the communication protocol of UPA (Universal Powerline Association) technology - one of Broadband PLC (BB-PLC) solutions, which are used today in the Smart Grid. In the paper the test field measurements of this technology are summarized and the development of the UPA simulation model is described. Among this description one of the most important stages of the simulation model design, i.e. calibration with the measurement results, is explained. The obtained simulation model is intended be used as a part of the PLC network planning tool.

CSMA/CD in PLC: Test with full G.hn and IP/UDP protocol stack

In this paper, we advocate implementing carrier sense multiple access with collision detection (CSMA/CD) in the broadband power line communication (BB-PLC) standard, G.hn, and show the gain in data rate obtained over carrier sense multiple access with collision avoidance (CSMA/CA). The use of CSMA/CD is made feasible due to the recent implementation of in-band full duplex operation in BB-PLC. We provide this implementation on a G.hn model using the NS-3 simulator, which we have made available as open-source. Our G.hn model implements physical and data link layers, including repeating function that makes it possible to simulate the long line network topologies (e.g., the network for electricity metering purpose). We also add IP/UDP layers to accomplish the higher layer protocol stack. We also provide analytical calculations of efficiency gains and validate them through our simulation results. We show that the highest achievable data rate with CSMA/CD is up to 5% higher than with CSMA/CA. Furthermore, we demonstrate that the protocol with CSMA/CD is less dependent on the number of active senders and has a smaller range of optimal contention window sizes (CW) for the same range of active senders, in comparison to CSMA/CA. This also simplifies the protocol implementation as the back-off algorithm for CSMA/CD does not vary CW as much as for CSMA/CA.

Adaptive Layer Switching for PLC networks with repeaters

Adaptive Layer Switching (ALS) is a mechanism that allows the changing of the Medium Access Control (MAC) layer of the Power Line Communication (PLC) network in the runtime. According to the delay-throughput tradeoff dependencies for Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) and Time Division Multiple Access (TDMA) it switches them for the corresponding network utilization. In this way the advantage of the low access delay for the low network utilization in CSMA/CA and high throughput for the high network utilization in TDMA are provided. In this paper we show the operation of the ALS for the PLC network with repeaters. The PLC networks that require repeaters are usually large. Therefore, a large sized network with 141 nodes is used for the simulation in this paper. The delay and throughput dependencies vs. offered traffic are found. Recommendations for the network operation and ALS usage are given based on these results in the conclusions.

Backoff algorithms performance in burst-like traffic

In the present paper several backoff algorithms are considered to analysis their behavior in burst-like traffic of smart metering network: YITRAN, Binary Exponential and Polynomial backoff algorithms. The comparison was performed by means of transmission successfulness probability estimation using Markov chain models for each algorithm. The results of the calculation showed that YITRAN algorithm outperforms the other ones for almost all kinds of burst-like traffic. The developed software can be used to implement other backoff algorithms and perform their comparison. A novel backoff algorithm was developed, which is basing on the results the comparison.