3.5.3 Time Synchronization and Orthogonal Codes 3.5.4 The Outbound Channel 3.5.5 Frequency Reuse and Antenna Sectorization 3.5.6 Narrowbeam and Delay-line Antennas Spread Spectrum CDMA for PCS/PCN 3.6.1 Binary Orthogonal Codes 3.6.2 S-CDMA Equivalent to Bit-Level TDMA 3.6.3 A High-Density Voice PCS System 3.6.3.1 Bit-Error Probabilities 3.6.3.2 Computer Simulations 3.6.3.3 Other System Issues 3.6.3.4 Comparison with DECT Higher Capacity Optional Receivers 3.8 Summary 3.9 References Appendix 3A: Multipath and Diversity Appendix 3B: Error Bounds for Interference-Limited Channels Index PREFACE In the nine years since the publication of the first edition of Spread Spectrum Communications, the world's political situation has changed con- siderably. The U.S. Department of Defense has reduced its support for the development of new communication systems as well as their acquisition. One might question the need for a second edition of a book written about robust techniques for anti-jamming (AJ) and low-probability-of-intercept (LPI) communications. However, while it is already painfully clear that the close of the Cold War has not ended warfare, the past decade has also ushered in a new era of mobile communications. The qualities that make spread-spectrum tech- niques useful in military communications-fine time-resolution, low power- density, privacy, and a high immunity to interference-are also extremely desirable in today's mobile communications systems. Encouraged by enlight- ened FCC actions, spread-spectrum technology is being transferred from the Department of Defense to the arena of commercial mobile cellular com- munications. The emerging markets for spread-spectrum systems have the potential to dwarf those of the past. Are the design techniques for military communication systems truly applicable to the commercial environment? Does yesteryear's jammer have anything to teach us about managing multiple-user noise in a spread-spec- trum multiple-access radio network? The answer-an unqualified "yes"-is attested to by 