Our work to develop distributed, dynamic routing protocols for broadcast wireless networks began over 30 years ago. The Navy's original interest in dynamic routing protocols was born from a desire to provide intratask force communication for naval battle groups at sea using networked HF radios and spread spectrum signaling. Early research introduced the concept of an architecture that consisted of node clusters that were interconnected by a backbone.
This "Linked Cluster" structure was developed and maintained by a distributed algorithm that periodically reorganized the network in response to connectivity changes. The Linked Cluster Architecture (LCA) facilitates regional or net-wide broadcasts by identifying "broadcast centers" (clusterheads). NRL demonstrated the first implementation of the LCA in 1990 as part of the Unified Networking Technology (UNT) project using a small (7-node) High Frequency (HF) wireless network with an fixed TDMA medium access control (MAC) layer, which could handle only data traffic. The success of this first series of tests led to research to further develop the LCA so that it could support voice, as well as data traffic (both unicast and broadcast).
In the mid-90's, with funding via the Data and Voice Integration Advanced Technology Demonstration (D/V ATD), NRL successfully field and lab tested a multi-channel implementation of the new architecture, called the Multi-Channel Architecture (MCA). Each node used a single transmitter and multiple receivers in a full duplex mode of operation. The D/V ATD added quality-of-service (QoS) capability that could support both differential and integrated services across multi-hop networks.
Under our current ONR project, Mobility Management for Heterogeneous Networks, we have selected 802.11 radios to host our (newly named) Dynamic Backbone Subnet (DBS) technology. 802.11 radios offer many advantages including low cost, low power, high bandwidth, compact, portable hardware, unlicensed operation, an efficient MAC protocol for single channel operation, and, most importantly, a place holder in the architecture, i.e., the Distribution System (DS), as an insertion point for DBS.