## 1 Introduction
In the revision of the general standard published in 2012, as well as in the current revision [4], mesh networks have been directly incorporated, although a large number of researchers continue to refer to them as IEEE 802.11s mesh networks. The main differentiating characteristic of this type of networks is that, from the upper layer point of view, all the stations appear as connected at the MAC level, although they might not be within the range of coverage. To make this possible, a layer 2 path search mechanism called the Hybrid Wireless Mesh Protocol (HWMP) was designed. In this article, some modifications on the basic mechanisms and protocols used by the IEEE 802.11 mesh networks are proposed, in order to improve their performance when using this technology as the implementation of the smart grid NANs. Mainly, a new multi-path mechanism is proposed and implemented in conjunction with a multi-channel allocation of the different available paths. These paths are assigned differently according to the quality of service demanded by every traffic. With this strategy, we intend to take better advantage of the available network resources, guaranteeing an adequate service to as much traffic as possible. In this way, the supplier companies can obtain greater benefits by being able to provide service to a higher number of clients or applications, while at the same time, they can offer more competitive prices to their customers. The study and comparison of the benefits obtained is based on simulations carried out with the ns-3 network simulator [5]. Thanks to the improvements obtained, especially in situations of high load, NAN networks could offer service to a greater volume of traffic and also allow a correct and differentiated quality of service for each application. In this way, new development challenges are created for both device manufacturers and electricity supplier companies, which will be able to offer new and better services to their customers. From our point of view, these new services should have a major impact on greater efficiency in the use of electricity and a faster and improved reaction in front of emergency situations. Smart grid networks have attracted the attention of numerous researchers in recent years. Among these investigations, several proposals have been presented in order to improve the benefits offered by the NANs, where both wired and wireless technologies have been taken into account [6]. Within the wired technologies, PLC stands out especially in this environment due to its ability to use the existing infrastructures. However, the available bandwidth with this technology is quite limited, and it also presents drawbacks when data signals must pass through electrical transformers. When the number of nodes in the network grows, as well as the bandwidth needs, other technologies must be considered. In this sense, wireless networks in general [7; 8] and wireless multi-hop networks in particular [9; 10] present a series of advantages that make them ideal candidates. For instance, they do not require previous infrastructures, and their bandwidths are constantly increasing. Besides, they have a great flexibility to modify the network topology and to take advantage of multi-channel and multi-path mechanisms that increase their performance in terms of, among others, availability, packet delivery ratio or network transit time. For these multi-hop wireless networks, a new and precise analytical model, which takes into account the hidden nodes problem, has been presented in [11]. In [12], an enhancement of the Optimized Link State Protocol (OLSR) in order to satisfy the required level of reliability in NANs is presented. The possibility of offering an adapted quality of service to the different data traffics transmitted through the network is taken into account. To this end, the authors proposed the use of a combination of different basic metrics: Expected Transmission Count (ETX), Minimum Delay (MD) and Minimum Loss (ML).