Spread spectrum communications Wireless communication systems 21 Code division multiple access 13 Multiplexing 13 Signal processing 12 Mobile communication systems 10 Radio 8 Digital communications 7 Design and construction 6 Telecommunication 6 Transmitter-receivers 6 Acoustic surface wave filters 5 Global Positioning System 4 Military telecommunication 4 Personal communication service systems 4 Traffic 4 Wireless Internet 4 MIMO systems 3 Cellular telephone systems 2 Digital modulation 2 Essays 2 Local area networks (Computer networks) 2 Orthogonal frequency division multiplexing 2 Orthogonalization methods 2 Radio frequency 2 Standards 2 Telecommunications 2