Capacity and delay tradeoffs in mobile networks under Gaussian channel model

Extensive efforts have been made to study the asymptotic capacity, delay, and their tradeoffs for large-scale mobile ad hoc networks, under different mobility models and communication models. Majority results adopt the fixed-rate communication model, such as the protocol model and physical model, and none of them breaks the limitation of tradeoffs: delay/capacity = ω(1) so far, even for the simplest i.i.d. model. In this work, we investigate this problem under the Gaussian channel model, and demonstrate that the delay-capacity tradeoffs can be further improved by designing new two-hop strategy under a general mobility model, called hybrid random walk mobility model (HRWMM). We found that the capacity and delay have several regions, depending on the freedom degree γ ∊ [0, 1] of mobile nodes. Specifically, we show that under the prerequisite of ensuring the optimal per-session capacity, i.e., of order Θ(1): (1) for 0 < γ ≤ 1, the optimal delay under the Gaussian channel model is smaller than that under the protocol model or physical model; (2) for γ = 0, i.e., ordinary random walk model, it is not larger than the delay under the protocol model or physical model; (3) for γ = 1, i.e., i.i.d. model, the capacity and delay can simultaneously achieve the optimal order, i.e., Θ(1).