Research Papers: Bhaskar Krishnamachari

Optimizing Content Dissemination in Vehicular Networks with Radio Heterogeneity

By Joon Ahn, Maheswaran Sathiamoorthy, Bhaskar Krishnamachari, Fan Bai, Lin Zhang

IEEE Transactions on Mobile Computing


Disseminating shared information to many vehicles could
incur significant access fees if it relies only on unicast cellular communications. We consider the problem of efficient content dissemination over a vehicular network, in which vehicles are equipped with two kinds of radios: a high-cost low-bandwidth, long-range cellular radio, and a free high-bandwidth short-range radio. We formulate and solve an optimization problem to maximize content dissemination from the infrastructure to vehicles within a predetermined deadline while minimizing the cost associated with communicating over the cellular connection. We examine numerically the tradeoffs between cost, delay and system utility in the optimum regime. We find that, in the optimum regime,
(a) system utility is more sensitive to the cost budget when the allowed
delay for the dissemination is not large, (b) the system requires relatively
smaller cost budget as more vehicles participate and more delay is
allowed, (c) when the cost is very important, it is better not to spread
the content if it needs small delay. We also develop a polynomial-time
algorithm to obtain the optimal discrete solution needed in practice.
Finally, we verify our analysis using real GPS traces of 632 taxis in
Beijing, China.

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