Introduction

The design of large-scale distributed wireless networks (e.g., mesh and ad-hoc networks, relay networks) poses a set of new challenges to information theory, communication theory, and network theory. Such networks are characterized by the large size of the network both in terms of the number of nodes (i.e., dense) and in terms of the geographical area the network covers. Each terminal can be severely constrained by its computational and transmission/receiving power. It is therefore important to understand how to utilize efficiently the physical infrastructure and system resources (power, bandwidth, etc.). Moreover, delay and complexity constraints along with diversity-limited channel behavior may require transmissions under insufficient levels of coding protection causing link outages. These constraints require an understanding of the performance limits of such networks and associated implications on network architectures jointly in terms of power and bandwidth efficiency and link reliability, especially when designing key operational elements essential in these systems, such as multihop routing and relay processing algorithms, bandwidth allocation policies, and relay deployment models.

Generally speaking, characterizing the fundamental limits of communication over large-scale distributed wireless networks is a difficult problem, owing to the highly complex nature of the information exchange among multiple terminals. Even the capacity of the classical relay channel is not solved yet. One simplification in this regard is to characterize the scaling laws, where the goal is to investigate how a certain performance measure (throughput, energy, delay, etc.) scales as the number of nodes in the network grows asymptotically large.