The spread spectrum technique, the collision avoidance multiple access protocols and the controlled time of arrival scheme are combined to form a new set of medium access protocols for wireless networks. The request-to-send and clear-to-send message dialogue helps a transmitter detect whether an intended receiver is busy and whether any collision has occurred; thus speeding up the retransmission. The spreading code assignment avoids the disruption of any ongoing transmission by an intruder. Finally, the packets are sent under controlled time of arrival to further increase the channel throughput. Simulation results confirm that a higher channel throughput is achieved by the new protocols even in a dense network.

This paper describes a robust method of improving TCP performance for terrestrial and satellite wireless networks without modification to TCP or change in its semantics. Tools to transparently improve performance have been around for many years and many work even when the TCP header information is encrypted (e.g., IPSEC) or TCP acknowledgments do not go through the reverse path. Little work has been done; however, to quantiy how beneficial these techniques are. Using protocol boosters we show that reducing the packet size is critical as bit error rates get worse than 10/sup -5/. We also show that over two orders of magnitude improvement in throughput can be achieved by adding redundant FEC packets, with well-chosen parameters for the number of data (k) and parity (h) packets in a block, and a small maximum encode time (t). It is important to note that we are looking strictly at enhancement techniques that do not require modifications at the end hosts as this can be a difficult task for the typical end user.

Spread spectrum techniques and collision avoidance multiple access protocols are combined to form a new set of medium access protocols for mobile wireless ad hoc networks. The request-to-send and clear-to-send message dialogue solves the "hidden terminal" and the "exposed terminal" problems and speeds up the retransmission. The spreading code assignment avoids disruption of any ongoing transmission by an intruder. Simulation results confirm that a higher channel throughput is achieved by the new protocols even in a dense network.

A new global positioning system (GPS)-based routing protocol for ad hoc networks, called zone-based hierarchical link state (ZHLS) routing protocol, is proposed. In this protocol, the network is divided into nonoverlapping zones. Each node only knows the node connectivity within its zone and the zone connectivity of the whole network. The link state routing is performed on two levels: focal node and global zone levels. Unlike other hierarchical protocols, there is no cluster head in this protocol. The zone level topological information is distributed to all nodes. This "peer-to-peer" manner mitigates traffic bottleneck, avoids single point of failure, and simplifies mobility management. Since only zone ID and node ID of a destination are needed for routing, the route from a source to a destination is adaptable to changing topology. The zone ID of the destination is found by sending one location request to every zone. Simulation results show that our location search scheme generates less overhead than the schemes based on flooding. The results also confirm that the communication overhead for creating and maintaining the topology in the proposed protocol is smaller than that in the flat LSR protocol. This new routing protocol provides a flexible, efficient, and effective approach to accommodate the changing topology in a wireless network environment.