# Random Violation Risk Degree Based Service Channel Routing Mechanism in Smart Grid
## 2 Related Work  
Currently, the body of work related to smart grid communication robustness is rapidly increasing. For the realization of smart grid, many studies have looked at the communication challenges in smart grid. Papers [6; 7; 8; 9] pointed the critical communication challenge of smart grid communications and also gave the feasible solutions and future directions from the overall perspective. One way is to improve the communication reliability by eliminating the defects of the technology itself. Paper [10] proposed an orthogonal poly-phase-based multicarrier code division multiple access (OPP-MC-CDMA) system and implemented with a minimum mean square error equalizer and nonlinear preprocessing to overcome the effects of noise and multipath frequency-selective fading commonly experienced in PLC channels. This way is the most effective but it depends on the update of corresponding communication technology and it is difficult to make great progress. The other way is to optimize the communication routing of communication service. Some studies adopt the method of optimizing the routing protocol of the corresponding communication network technology. Paper [11] presented a QoS-aware wireless mesh network (WMN) routing technique that employed multiple metrics in optimized link state routing (OLSR) for AMI applications in a smart grid neighbor area network based wireless mesh network. They indicate to guarantee the optimized communication routing. Other studies turn to solve the service channel failure risk problem to guarantee the effective communication routing. The main way is to control the \(SCVR\) by routing method. There are two kinds of routing methods: availability-aware routing based on statistics (AAR-OS) and availability-aware routing based on uncertainty (AAR-OU). In respect of AAR-OS, the difference between \(A_{SPA}\) and \(A_{APA}(t)\) and how availability changes over time and geographical locations are pointed out in Reference [13]. Based on the new availability calculation method, the 3W-availability aware routing (3 WAR) algorithm was proposed in that paper which effectively narrowed the gap between the actual availability and target availability. In paper [14], the definitions of min cross layer cut (MCLC) and min cross layer spanning tree (MCLST) were given and the availability routing algorithm under different failure probability conditions was proposed to maximize the MCLC and minimize the MCLST. Paper [15] adopted the log information of path state as the basis for routing and considered the path with highest statistics availability as the service channel. Papers [16; 17; 18] proposed \(A_{SPA}\) based multipath routing mechanism by increasing the redundancy of resources to enhance the \(A_{SPA}\) of the channel. Paper [19] proposed a primary-backup sharing routing mechanism in optical networks to improve the resource utilization in premise of ensuring the statistical availability. In paper [20], the cost of routing was taken into account in routing algorithm to minimize the cost in premise of ensuring the statistics availability. The methods mentioned above are all using the \(A_{SPA}\) as the decision indicator in routing mechanism. The advantages of those methods are simple, easy to reflect the availability in the overall trend and clear in physical meaning. But \(A_{SPA}\) only has statistical meaning, which can reflect the availability variation trend on the whole but cannot reflect the actual availability fluctuations of channel. Thus, the threat to the grid due to network random failures cannot be effectively reduced by those methods. In the aspect of AAR-OU, papers [21; 22; 23; 24; 25] all studied the uncertainty of the path availability during a short time period. Paper [21] proposed a dynamic availability-aware survivable routing architecture to provide the service path protection based on the partial restorability.