Smart Antennas Smart antennas are an important application of SDR technology [381]. An in-depth treatment is beyond the scope of this chapter. The objective is to introduce the topic to identify the implications of smart antennas for softwareradio architecture. The smart antenna is a logical extension of antenna diversity described above [382]. Smart antenna arrays integrate the contributions of spatially distributed antenna elements to provide wireless communication systems with larger capacity and higher link quality through frequency reuse and cochannel interference suppression [383, 384] | Software Radio Architecture Object-Oriented Approaches to Wireless Systems Engineering Joseph Mitola III Copyright 2000 John Wiley Sons Inc. ISBNs 0-471-38492-5 Hardback 0-471-21664-X Electronic 14 Smart Antennas Smart antennas are an important application of SDR technology 381 . An in-depth treatment is beyond the scope of this chapter. The objective is to introduce the topic to identify the implications of smart antennas for softwareradio architecture. The smart antenna is a logical extension of antenna diversity described above 382 . Smart antenna arrays integrate the contributions of spatially distributed antenna elements to provide wireless communication systems with larger capacity and higher link quality through frequency reuse and cochannel interference suppression 383 384 . Since smart antennas require an order of magnitude more IF and baseband digital processing capacity than a conventional receiver the smart antenna base station is 90 antenna. Contrast this to a conventional base station which is only 10 antenna including diversity processing. The rate of proliferation of the smart antenna technology in the commercial sector has been slow because of the cost of this increase in capability. I. SMART ANTENNA DOMAINS Four applications domains attract investments in smart antenna technology as illustrated in Figure 14-1. Historically military radar and communications jamming laid the foundations of smart antenna technology. Investment leadership has shifted to commercial terrestrial networks however. For example a smart antenna with per-subscriber AOA estimation interference differentiation and coherent multipath combining was demonstrated for AMPS in 1994 385 386 . In addition GSM infrastructure is amenable to smart antenna applications 387 . In the future 3G base stations with W-CDMA 1 1 frequency reuse also should benefit from this technology 388 . Military applications remain substantial. Technology for beamforming on transmit for communications for .
