Project Overview
 

Principal Investigators:
Joseph B. Evans
Associate Professor
Electrical Engineering & Computer Science
University of Kansas
evans@ittc.ku.edu
K. Sam Shanmugan
AT&T Distinguished Professor
Electrical Engineering & Computer Science
University of Kansas
shanmuga@ittc.ku.edu

Co-Investigators:
Victor S. Frost Dan F. Servey Distinguished Professor
Gary J. Minden Professor
David W. Petr Associate Professor
Glenn Prescott Associate Professor
James A. Roberts Professor
Electrical Engineering & Computer Science
University of Kansas

Objective:

The primary objective of the project is to create architectures, protocols, and prototype hardware and software for a high speed network that can be deployed rapidly in areas of military conflicts or civilian disasters where communication infrastructures are lacking and or destroyed (e.g. Desert Storm, Bosnia, Hurricane Andrews, LA, Turkey, Taiwan earth quake).

Approach:

The rapid deployment requirement coupled with higher speed requirements and seamless integration with other commercial networks has lead to an approach that uses wireless technology for the communication links and ATM for networking. The Rapidly Deployable Radio Network (RDRN) being developed by the University of Kansas is a wireless ATM network and it consists of portable (mobile) communication nodes which can be deployed on the ground or on mobile platforms such as trucks, helicopters or fixed wing aircrafts. When deployed, the nodes use GPS derived location information to automatically configure themselves into a high capacity, fault tolerant network infrastructure.

RDRN is made up of two types of nodes: end user nodes providing wireless ATM access for users at a rate of up to 1.5 Mbit/s and edge nodes which serve as Radio Access Points (RAPs) or base stations and provide switching and connectivity between users. Both types of nodes contain GPS receivers for location determination, software controlled radios with phased-array antennas for beam forming and pointing in the right direction using GPS derived location information, and network control software. The edge nodes also have integral ATM (software) switches and they are interconnected by high capacity (45 to 155 Mbit/s) directional radio links. Edge nodes can also interface to wired ATM networks.

The RDRN architecture consists of three overlaid radio networks: (1) a low bandwidth, low power, omni-directional order wire packet radio network for broadcasting location information, network configuration and management; (2) a cellular like ATM radio network for end user access to edge nodes with hand-offs, and (3) a high capacity wireless ATM backbone network providing connection between switches using high capacity radios with multiple directional beams.

When RDRN is initially deployed in a new area, each of the edge nodes initiate the following activities: (1) determine its location from GPS and broadcast it over the secure orderwire network; (2) listen for broadcasts from other nodes; (3) establish the backbone network by forming high capacity, directional radio links to nearby nodes using the steerable phased array antenna; and (4) begin executing the distributed network configuration and control algorithm and establish connectivity with end user nodes.

Each edge node is capable of forming multiple radio beams in the direction of other edge nodes or towards end users in the vicinity. A phased array antenna with digital beam forming is used to form these multiple beams, and pointing directions are derived from location information. Assignment of beams to users, node to node connections, and handoffs of users from one edge node to another are controlled by the distributed network configuration and management algorithm. The network control information is broadcast over the orderwire network. Changes in network topology due to mobility or failure of nodes and or links are detected by the network control algorithms and reconfiguration is carried out automatically in a distributed manner.

RDRN is also adaptable to changes in the quality of the radio communication environment. While ATM is designed to operate on high quality (almost error free) wired links, typical radio links suffer higher error rates and the link quality changes as a function of time due to mobility and changes in the environment. By estimating the channel parameters such as multipath spread and signal to noise ratio, communication parameters at the link and network levels are adapted to provide appropriate throughput and quality of service.


Last Update: October 19, 1999 10:00am (GMT-0600)