Asymptotic Laws for Joint Content Replication and Delivery in Wireless Networks

We investigate on the scalability of multihop wireless communications, a major concern in networking, for the case that users access content replicated across the nodes. In contrast to the standard paradigm of randomly selected communicating pairs, content replication is efficient for certain regimes of file popularity, cache and network size. Our study begins with the detailed joint content replication and delivery problem on a 2D square grid, a hard combinatorial optimization. This is reduced to a simpler problem based on replication density, whose performance is of the same order as the original. Assuming a Zipf popularity law, and letting the size of content and network both go to infinity, we identify the scaling laws and regimes of the required link capacity, ranging from O(\sqrt{N}) down to O(1)

Asymptotic capacity bounds for wireless networks with non-uniform traffic patterns

Abstract — We develop bounds on the capacity of wireless multihop networks when the traffic pattern is non-uniform, i.e., not all nodes are the sources and sinks of similar volumes of traffic. Our results are asymptotic, i.e., they hold with probability going to unity as the number of nodes goes to infinity. We study (i) asymmetric networks, where the numbers of sources and destinations of traffic are unequal, (ii) multicast networks, in which each created packet has multiple destinations, (iii) cluster networks, that consist of clients and a limited number of cluster heads, and each client wants to communicate with any one of the cluster heads, and (iv) hybrid networks, in which the nodes are supported by a limited infrastructure. Our findings quantify the fundamental capabilities of these wireless multihop networks to handle traffic bottlenecks, and point to correct design principles that achieve the capacity without resorting to overly complicated protocols. Index Terms — Asymmetric traffic, capacity, clustering, hybrid networks, infrastructure support, mobile ad hoc networks, multiho