دانلود رایگان مقاله ارزیابی عملکرد سیستم ارتباط خط نیرو در خانه پهن باند با پروتکل MAC

Abstract

In this article, we present an in-depth analysis of cooperation benefits in power line communication (PLC) networks. In order to conduct our evaluation, we present a new, yet simple, cooperative medium access control protocol (CMAC). Our new CMAC protocol uses system nodes as relays adaptively, according to these nodes idleness or busyness. Moreover, the new protocol also explores path diversity offered by an in-home broadband PLC. We have conducted simulations, based on real packet error ratios of in-home networks, using a wide range of configurations. In sum, our results show that cooperation reduces packet loss ratio and improves goodput. For instance, in some scenarios, the protocol we proposed is able to enhance goodput up to 36% and reduce packet loss ratio up to 43% in comparison to a system without cooperative protocols. Moreover, our simulations allow us to delimit the most suitable scenarios to use cooperation. Based on our analyses, we can state the following: (i) improvements increase when frequency bandwidth increases; (ii) irrelevant improvement occurs if total transmission power is too high or too low; (iii) gains offered by cooperation are more relevant depending on relative node relay position in relation to nodes source and destination; (iv) the proposed protocol show improvements regardless of the choice between OFDMA-TDMA and TDMA-OFDM schemes, but improvements are higher when it is used together with the OFDMA-TDMA scheme.

6. Conclusion

In this work, we have addressed comprehensive analyses of cooperative communication at link layer of inhome PLC system. We focused on revealing, for the first time, under which circumstances the use of a cooperative MAC protocol may improve this scenario when we consider single relay model. To support this investigation, we presented statistics of packet error ratio estimates calculated from measured in-home PLC channels. Additionally, we described a simple cooperative MAC protocol, capable of exploiting diversity offered by electric power grids to improve in-home PLC system performance. Based on numerical results, we showed that the proposed cooperative MAC protocol (PLC–CMAC) can reduce packet loss ratio up to 43%, compared with a PLC system without cooperation. Moreover, the use of PLC–CMAC protocol enhances system goodput in 36%. Furthermore, we observed, in our simulations, that cooperation improvements increase as frequency bandwidth increases. Also, cooperation may not be useful if total transmission power is very low or very high, because, in these situations, PER values in links SD, SR and RD do not benefit diversity improvements on communication. Additionally, we have concluded that cooperation tends to offer better results when node relay is located closer to node source or in midway between nodes source and destination, considering a single relay model. In terms of simulated protocols, PLC–CMAC protocol has shown better results in comparison with non-cooperative PLC systems than other cooperative protocols adapted from wireless communication. In fact, differently than other analyzed protocols, the proposed protocol exploits busyness and idleness of node relay adaptively.