n- dent of the interference signal. In fact, for many CDMA systems where sig- nals are not independent, the Gaussian approximation is also justified, although the resulting variance may be different [65]. In this section we assume radios in a network where different keys have statistically indepen- dent pseudorandom sequences associated with them and that each sequence is modelled as a sequence of independent equal probable binary random variables. We refer to this case as SSMA as opposed to CDMA where dif- ferent keys correspond to sequences designed to have low cross-correlation properties. Our assumption here is that the primary purpose in using DS/BPSK waveforms is to combat jamming and the multiple access capa- bility is a secondary additional property we can use for multiple access in digital radio networks. Throughout this section assume that pseudorandom sequence acquisition and synchronization can be easily achieved by the intended receiver. This discussion is limited to the idealized assumption that the receiver for the desired DS/BPSK signal is perfectly synchronized in frequency, phase, chip epoch, and bit epoch. Also assume all radios are asynchronous and there is no network control or common time reference among the radios. As stated earlier for our example distributed radio network each radio has a unique key or pseudorandom sequence assigned to it as well as a common network key shared by all radios. During certain known fixed times the network key is used by all radios. Otherwise, each radio uses its own unique key for receiv- ing DS/BPSK transmissions and each radio can transmit DS/BPSK wave- forms with the key corresponding to some other radios. In this context we examine SSMA properties of DS/BPSK waveforms. 2.3.1 Point-to-Point The analysis of Chapter 1 of Part 2 applies directly to the point-to-point com- munications system where the interference or jamming signal is due to other users in the radio network. Suppose that while a transmitter and synchro- nized receiver are communicating, the i