Throughput-Delay Trade-Off In Wireless Networks

Gupta and Kumar (2000) introduced a random network model for studying the way throughput scales in a wireless network when the nodes are fixed, and showed that the throughput per source-destination pair is Theta (1 / rootn log n). Grossglauser and Tse (2001) showed that when nodes are mobile it is possible to have a constant or Theta (1) throughput scaling per source-destination pair.The focus of this paper is on characterizing the delay and determining the throughput-delay trade-off in such fixed and mobile ad hoe networks. For the Gupta-Kumar fixed network model, we show that the optimal throughput-delay trade-off is given by D(n) = Theta (nT (n)), where T(n) and D(n) are the throughput and delay respectively. For the Grossglauser-Tse mobile network model, we show that the delay scales as Theta (n (1/2) / upsilon(n)) , where upsilon(n) is the velocity of the mobile nodes. We then describe a scheme that achieves the optimal order of delay for any given throughput. The scheme varies (i) the number of hops, (ii) the transmission range and (iii) the degree of node mobility to achieve the optimal throughput-delay trade-off. The scheme produces a range of models that capture the Gupta-Kumar model at one extreme and the Grossglauser-Tse model at the other. In the course of our work, we recover previous results of Gupta and Kumar, and Grossglauser and Tse using simpler techniques, which might he of a separate interest.