  The vision for smart city imperiously appeals to the implementation of
Internet-of-Things (IoT), some features of which, such as massive access and
bursty short packet transmissions, require new methods to enable the cellular
system to seamlessly support its integration. Rigorous theoretical analysis is
indispensable to obtain constructive insight for the networking design of
massive access. In this paper, we propose and define the notion of massive and
sporadic access (MSA) to quantitatively describe the massive access of IoT
devices. We evaluate the temporal correlation of interference and successful
transmission events, and verify that such correlation is negligible in the
scenario of MSA. In view of this, in order to resolve the difficulty in any
precise spatio-temporal analysis where complex interactions persist among the
queues, we propose an approximation that all nodes are moving so fast that
their locations are independent at different time slots. Furthermore, we
compare the original static network and the equivalent network with high
mobility to demonstrate the effectiveness of the proposed approximation
approach. The proposed approach is promising for providing a convenient and
general solution to evaluate and design the IoT network with massive and
sporadic access.
