erence and multiple access techniques in general, followed by the examination of the two questions raised above on mutual interference and multiple access with spread-spectrum signals. 2.1 NETWORKS There are many different types of military communication networks and these are often interconnected to form parts of larger networks resulting in layers of communication networks. To place in some context and to moti- vate the mutual interference and multiple access problems that we examine in this chapter, consider two generic examples of radio and satellite com- munication networks where some or all terminals may be mobile. 2.1.1 Decentralized (Point-to-Point) Networks Consider a collection of mobile radios scattered across some terrain. Assume each radio has an omni-directional antenna with no prior knowledge of the location of other radios. All radios use spread-spectrum signals for combat- ting intentional jamming where each radio has a unique key that generates a PN sequence assigned to it and can also generate the PN sequence Multiple Access Figure 2.5. Illustration of flooding. assigned to some of the other radios. Acquisition and synchronization of these PN sequences is assumed throughout this chapter. Also there is enough processing capability and memory in each radio to maintain and update knowledge of the overall network connectivity between radios. Assume there is no central controller and each radio is within range of some subset of all radios in the terrain. Consider only point-to-point communication between any two radios. Specifically, for the generic mobile digital radio network described, how does one radio communicate digital data to another radio? Since we do not assume full connectivity among radios, this is a multihop communication net- work. That is, a communication link between two radios in this network typ- ically requires other radios to act as relays. One brute force method, called "flooding" [3], [5]-[7], is illustrated in Figure 2.2. Suppose Radio A wants to send a message to Radio B but