Martin J. Feuerstein

The future of smart antennas: evolution to 3G and IP networks

Over the next few years, service providers will begin deploying 3G wireless air interfaces to increase capacity and support new multimedia services. For the first time network operators will be able to select from multiple radio access technologies that can interface with either GSM UAP or ANSI-4I core networks. As a part of this evolution, wireless systems will migrate to IP-based core networks to take advantage of the cost efficiencies associated with Internet infrastructure. With further maturity of voice over IP technology, wireless air interfaces themselves will shift to IP over the radio link. With spectrum being a limited commodity service providers will be challenged to extract maximum capacity from their networks. Smart antennas provide an attractive means of increasing the capacity of todays 2G voice networks, as well as tomorrows 3G Internet and multimedia networks. This paper examines smart antenna architectures for both CDMA and GSM networks. Emphasis is placed on their real-world performance in cellular and PCS networks. The first smart antenna is designed for CDMA networks, with the goal of addressing many of the fundamental performance limitations that exist within these networks. The smart antenna is implemented as a non-invasive add-on to current CDMA base stations. The second antenna is designed as an integral subsystem embedded within specially adapted 3G CDMA base stations. The embedded architecture increases the CDMA air link capacity by 100% to 200% through beam processing for each traffic channel. The third antenna is designed for current GSM and evolving GPRS/EDGE networks.

CDMA smart antenna performance

Applications of smart antenna technology to CDMA networks include both high-mobility cellular/PCS as well as fixed-terminal and low-mobility wireless local hop deployments. Smart antennas are emerging as an integral element of the new wideband CDMA standards for third generation mobile telephone systems across North America, Europe and Asia. This paper proposes a realizable architecture that applies smart antennas to current TIA/IS-95 CDMA networks; the approach employs a noninvasive applique technique designed to address many of the fundamental performance limitations that exist with current CDMA networks. The design integrates naturally with existing smart antenna architectures for analog AMPS service. Computer simulations are used to examine improvements in capacity and performance employing the fixed-beam technology. The non-traditional roles phased-array antenna deployments can play in traffic load balancing, handoff management and network-wide interference control are explored.

Methods for Measuring and Optimizing Capacity in CDMA Networks Using Smart Antennas

Smart antennas for CDMA networks have now entered commercial service in a number of IS-95 cellular markets, where they are used to increase capacity through traffic load balancing, managing handoff activity and reducing interference. With the introduction of CDMA smart antennas comes the complex question of how best to first measure and then to optimize capacity. This paper outlines an approach for estimating the forward link capacity of a CDMA cell site using readily available CDMA metrics obtained from switch statistics and drive test data. This capacity model is applied to a realworld smart antenna in a commercial deployment, where a 27% capacity improvement is projected over the existing conventional antenna system

Use of Smart Antennas to Increase Capacity in Cellular & PCS Networks

The chapter examines three different smart antenna architectures and their real-world performance in cellular and PCS networks. The first smart antenna is designed for cdmaOneTM. (EIA-95) CDMA cellular networks, with the goal of addressing many of the fundamental performance limitations that exist within these networks. The smart antenna is implemented as a non-invasive add-on (i.e. an applique) to current cdmaOneTM base stations, and improves capacity in CDMA networks through traffic load balancing, handoff management and interference control. Capacity improvements of greater than 50% have been achieved with the CDMA applique smart antenna through static and dynamic sector beam forming. The second smart antenna is designed as an integral subsystem embedded within specially adapted cdmaOneTM and 3G cdma2000TM base stations. The embedded architecture increases CDMA air link capacity by 100% to 200% through beam processing for each traffic channel. The third smart antenna, designed for current GSM networks, is implemented as an applique to existing base stations, and increases GSM air link capacity by 50% to 120% through increasing traffic channel carrier-to-interference (C/I) ratios, enabling increased fractional loading in frequency hopped networks.