Impact of Location Popularity on Throughput and Delay in Mobile Ad Hoc Networks

With the advent of smart portable devices and location-based applications, user's mobility pattern is found to be highly dependent on varying locations. In this paper, we analyze asymptotic throughput-delay performance of mobile ad hoc networks (MANETs) under a location popularity based scenario, where users are more likely to visit popular locations. This work provides a complementary perspective compared with previous studies on fundamental scaling laws for MANETs, mostly assuming that nodes move uniformly in the network. Specifically, we consider a cell-partitioned network model with cells of known popularity, which follows a Zipf's law distribution with popularity exponent alpha. We first conduct the analysis under traditional store-carry-forward paradigm, and find that location heterogeneity affects the network performance negatively, which is due to the waste of potential transmission opportunities in popular cells. Motivated by this observation, we further propose a novel store-carry-accelerate-forward paradigm to enhance the network communication, exploiting these potential transmissions. Theoretical results demonstrate that our proposed scheme outperforms all delay-capacity results obtained in conventional scheme for any alpha. In particular, when alpha = 1, it can achieve a constant capacity with an average delay of Theta(root n) (except for a polylogarithmic factor), while the delay is Theta(n) in conventional scheme. And by letting alpha = 0, our results can cover Neely's scaling laws. Moreover, we show that the delay-capacity tradeoff ratio satisfies >=Theta(root n), revealing that exploiting location popularity can effectively improve the performance in MANETs.