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smart antenna technology
Smart Antenna Technology for Mobile Communication sys
PER H. LEHNE AND MAGNE PETTERSEN, TELENORRE SEARCH AND DEVELOPMENT
ABSTRACT
The technology of smart or adaptive antennas for mobile communications has received enormous interest worldwide in recent years. The purpose of this article is to give an overview of the technology and of the different ways in which it is foreseen to influence mobile communications systems. A broad definition of smart antennas is used in this article, namely base station antennas with a pattern that is not fixed, but adapts to the current radio conditions. The article starts with an explanation of the basic principles of smart antennas. Different levels of intelligence are introduced, ranging from simple switching between predefined beams to optimum beamforming. Also, an evolutionary path for the development of smart antennas is suggested.
A discussion of the consequences for mobile systems is given. The principle reason for introducing
smart antennas is the possibility for a large increase in capacity: an increase of three times for TDMA systems and five times for CDMA systems has been reported. Other advantages include increased range and the potential to introduce new services. Major drawbacks and cost factors include increased transceiver complexity and more complex radio resource management.
The basic principles for implementation of smart antennas at the base stations are explained. First, the general principles for beamforming using array antennas are explored, then the special cases of different smart antenna implementations are discussed. Also, the fundamental difference between performing beamforming on uplink (base station receiving) and
downlink (base station transmitting) is dealt with. Special attention is given to the critical factors and technological challenges, including achieving equal performance on uplink and downlink as well as real-time calibration of the receiver and transmitter chains. The article concludes
with a short description of some of the trials and testbeds that have been implemented. In the autumn of 1998 Ericsson, in cooperation with Mannesmann Mobilfunk in Germany, became
the first to allow commercial traffic through a base station employing smart antennas.
Smart Antenna Technology for Mobile Communication sys
PER H. LEHNE AND MAGNE PETTERSEN, TELENORRE SEARCH AND DEVELOPMENT
ABSTRACT
The technology of smart or adaptive antennas for mobile communications has received enormous interest worldwide in recent years. The purpose of this article is to give an overview of the technology and of the different ways in which it is foreseen to influence mobile communications systems. A broad definition of smart antennas is used in this article, namely base station antennas with a pattern that is not fixed, but adapts to the current radio conditions. The article starts with an explanation of the basic principles of smart antennas. Different levels of intelligence are introduced, ranging from simple switching between predefined beams to optimum beamforming. Also, an evolutionary path for the development of smart antennas is suggested.
A discussion of the consequences for mobile systems is given. The principle reason for introducing
smart antennas is the possibility for a large increase in capacity: an increase of three times for TDMA systems and five times for CDMA systems has been reported. Other advantages include increased range and the potential to introduce new services. Major drawbacks and cost factors include increased transceiver complexity and more complex radio resource management.
The basic principles for implementation of smart antennas at the base stations are explained. First, the general principles for beamforming using array antennas are explored, then the special cases of different smart antenna implementations are discussed. Also, the fundamental difference between performing beamforming on uplink (base station receiving) and
downlink (base station transmitting) is dealt with. Special attention is given to the critical factors and technological challenges, including achieving equal performance on uplink and downlink as well as real-time calibration of the receiver and transmitter chains. The article concludes
with a short description of some of the trials and testbeds that have been implemented. In the autumn of 1998 Ericsson, in cooperation with Mannesmann Mobilfunk in Germany, became
the first to allow commercial traffic through a base station employing smart antennas.