 Concepts and System Models The total spread-spectrum signal bandwidth available, W SS' may not neces- sarily be contiguous; and it may be that a spread-spectrum system does not use all of this available bandwidth. Nevertheless, we define Wss as the total available signal bandwidth and its definition is independent of how it is used. The data rate, Rb, is the uncoded information rate to be transmitted over the spread-spectrum communication link; this definition is independent of the use of coding. The signal power S and jammer power J are the time-aver- aged powers at the intended receiver. If, for example, the jammer transmits a pulsed signal where high peak power is achieved over short time intervals, the time-averaged power is still J. In practice, this relationship between peak power and average power may not always apply. Regardless of the signal and jammer waveforms, an equivalent bit energy- to-jammer noise ratio is defined as (3.3) where we define processing gain (PG) (3.4) = jammer-to-signal power ratio. (3.5) In decibels (dB), the bit energy-to-jammer noise ratio is (3.6) where (3.7) In this work, bit error bounds are derived as a function of this Eb/N, for var- ious spread-spectrum systems and various types of jamming waveforms. Note again that all of these definitions are independent of the type of spread-spectrum system being used, including the use of coding. The purpose of defining all of these basic parameters, independent of specific system details, is SO that the performance of different systems for the same set of overall system parameter values can be compared. The particular definition of processing gain given in (3.4) may not agree with the definition of pro- cessing gain as the ratio of spread bandwidth to unspread signal bandwidth. This latter definition depends on both the modulation and coding technique used and is not as fundamental as the definition (3.4) used throughout this work. Jammer Waveforms For most of the performance evaluations in this work, it is assumed that the jammer limi