  Smart grid is an emerging technology which is able to control the power load
via price signaling. The communication between the power supplier and power
customers is a key issue in smart grid. Performance degradation like delay or
outage may cause significant impact on the stability of the pricing based
control and thus the reward of smart grid. Therefore, a QoS mechanism is
proposed for the communication system in smart grid, which incorporates the
derivation of QoS requirement and applies QoS routing in the communication
network. For deriving the QoS requirement, the dynamics of power load and the
load-price mapping are studied. The corresponding impacts of different QoS
metrics like delay are analyzed. Then, the QoS is derived via an optimization
problem that maximizes the total revenue. Based on the derived QoS requirement,
a simple greedy QoS routing algorithm is proposed for the requirement of high
speed routing in smart grid. It is also proven that the proposed greedy
algorithm is a $K$-approximation. Numerical simulation shows that the proposed
mechanism and algorithm can effectively derive and secure the communication QoS
in smart grid.
