A distributed topology-control algorithm has been developed for each node in a packet radio network (PRN) to control its transmitting power and logical neighbors for a reliable high-throughput topology. The algorithm first constructs a planar triangulation from locations of all nodes as a starting topology. Then, the minimum angles of all triangles in the planar triangulation are maximized by means of edge switching to improve connectivity and throughput. The resulting triangulation at this stage, the Delaunay triangulation, can be determined locally at each node. The topology is modified by negotiating among neighbors to satisfy a design requirement on the nodal degree parameter. Simulations show that the final topology is degree-bounded, has a rather regular and uniform structure, and has throughput and reliability that are greater than that of a number of alternative topologies.>

Code-division multi-access (CDMA) techniques allow many users to transmit simultaneously in the same band without substantial interference by using approximately orthogonal (low cross-correlation) spread-spectrum waveforms. Two-phase algorithms have been devised to assign and reassign spread-spectrum codes to transmitters, to receivers and to pairs of stations in a large dynamic packet radio network in polynomial times. The purpose of the code assignments is to spatially reuse spreading codes to reduce the possibility of packet collisions and to react dynamically to topological changes. These two-phase algorithms minimize the time complexity in the first phase and minimize the number of control packets needed to be exchanged in the second phase. Therefore, they can start the network operation in a short time, then switch to the second phase with the goal of adapting to topological changes. A pairwise code-assignment scheme is proposed to assign codes to edges. Simulations based on well-controlled topologies (sparse topologies) show that the scheme requires much fewer codes than transmitter-based code assignment, while maintaining similar throughput performance.>

Four connectivity measures are used to compare the reliability of various sparse topologies for packet radio networks. Different scenarios, including link failures, node failures, and both types of failures, were simulated for fixed-radius, nearest-neighbor, angle-constrained, degree-constrained, and Delaunay triangulation-based topologies. The simulation results demonstrated that the commonly used fixed-radius topologies were the worst among all topologies tested. Also, the results showed that triangulation-based and angle-constrained topologies maintained high reliability even under component failures.>

A novel, distributed topology-control algorithm has been developed for each node in a packet radio network (PRN) to control its transmitting power and logical neighbors in order to construct a reliable, high-throughput topology. The algorithm first constructs a planar triangulation from locations of all nodes as a starting topology. Then, the minimum angles of all triangles in the planar triangulation are maximized by means of edge switching to improve connectivity and throughput. The resulting Delaunay triangulation can be determined locally at each node. The topology is modified by negotiating among neighbors to satisfy a design requirement on the nodal degree parameter. Simulations show that (1) the final topology is degree-bounded, (2) it has a rather regular and uniform structure, and (3) its throughput and reliability are greater than that of a number of alternative topologies.>

Two-phase algorithms are devised to assign and reassign spread-spectrum codes to transmitters, to receivers, and to pairs of stations in a large dynamic packet radio network (PRN) using code-division multiple access (CDMA). The algorithms minimize the time complexity in the first phase and minimize the number of control packets needed to be exchanged in the second phase. A new pairwise code-assignment scheme is proposed to assign codes to edges. Simulations based on well-controlled topologies (sparse topologies) show that the proposed scheme requires much fewer codes than transmitter-based code assignment, while maintaining throughput performance.>