Wireless home area networks in smart grids: Modelling and delay analysis

Several interconnected layers of network form the smart grid. The Home Area Network (HAN) is the lowest layer of this grid, where reports about the various parameters associated with electrical devices are generated. For example, parameters could include information about the operation, power consumption, energy losses, power factor, etc. associated with the electrical devices. The reports generated are often classified as either periodic or critical. The critical reports are required to be communicated to a control station with minimal delay so that corrective measures could be taken quickly at the site of the electrical device. This paper presents the modelling and delay of wireless HANs. The communication between electrical devices and their associated access point can be achieved using several architectures, such as Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA). For each of these multiple access techniques upper and lower bounds on delay are derived. These bounds are a function of Signal-to-Noise Ratio (SNR), channel interference range, and the number of electrical devices and channels. It is noted that transmission of critical reports from electrical devices to their access point under the CDMA scheme achieves the least delay among the three multiple access techniques considered in the paper.