Communications: directive radio wave systems and devices (e.g. – Directive – Utilizing correlation techniques
Reexamination Certificate
1999-06-11
2001-06-26
Pihulic, Daniel T. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Utilizing correlation techniques
Reexamination Certificate
active
06252548
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a transceiver arrangement for a smart antenna system of a mobile communication base station. More particularly, the apparatus of the present invention which combines all the signals from an array of N antennas in accordance using frequency division multiplexing (FDM) and processes them with a wide-band transceiver, and sends all information from N antennas to beam forming modules in a base frequency band, allowing for adaptive beam forming.
DESCRIPTION OF THE RELATED ART
Generally, a term adaptive array is applied to a very intelligent or smart antenna. A smart antenna automatically changes its radiation patterns in response to its signal environments and directs an optimum directional beam in the direction by users and directs pattern nulls toward interference. A smart antenna receives signals and determines the beam direction needed to maximize SNIR (signal to noise ratio+interference) from the signals. Also, the smart antenna is capable of arbitrarily combining beams, selecting of a beam of having the strongest signal, dynamically pursuing for moving objects, removal of channel interference signals and making use of signals in all directions.
Smart antenna offers additional benefits such as high antenna gain, interference/multipath rejection, spatial diversity, good power efficiency, better range/coverage, increased capacity, higher bit rate, and lower power consumption.
On the other hand, smart antennas exhibit drawbacks that include requiring significant computation to identify optimum beam in a radio environment, so that it is difficult to perform a real time processing. In addition, hardware development for supporting the function of smart antennas tends to be a long and costly process.
In general, smart antenna systems include a sectored antenna, a diversity antenna, switched beam antenna and an adaptive array antenna.
Known smart antenna systems provides a basis for the next generation of a mobile communication systems in accordance with this invention to improve coverage and capacity over the conventional code division multiple access (CDMA) systems by forming an adaptive beam for each subscriber with using received signals from N array antennas, and improving signal to interference ratio (SIR) and signal to noise ratio (SNR) performance.
FIG. 1
illustrates a prior art structure of a smart antenna system of a mobile communication base station. The smart antenna system of
FIG. 1
uses N array antennas and needs N transceivers, compared to a CDMA base station which does not use a smart antenna system.
As shown in the
FIG. 1
, N array antennas need N antenna front-end units (AFEUs), N high power amplifiers (HPAs) and N transceivers, respectively. Also, N analog-to-digital converters and N digital-to-analog converters. The N analog-to-digital converters and N digital-to-analog converters all must be connected to L beam forming modules in order to process L subscribers.
Prior art smart antenna system have drawbacks in that they require more transceivers and modules due to increasing of the number of antennas up to N, and they cause increased complexity of the system configuration, higher power consumption, higher fabrication costs, expansion of the system configuration, and increase of related cable requirement and they make physical configuration of the system difficult.
U.S. Pat. No. 5,610,617, entitled “Directive beam selectively for high speed wireless communication networks” (filed in Jul. 18, 1995 and published in Mar. 11, 1997) discloses another prior art system directed toward providing a technique for selecting a direct beam in a wireless communication network
The prior art technique relies on Burtler matrix combiner circuit switching between a transmitter and an antenna array, and narrow beam width for selecting a transmission path having an optimum signal quality.
Such a prior art antenna array may have advantages such as reduction of power consumption, expansion of coverage range, improvements of the antenna array efficiency, and lower fabrication costs. However, such an array which chooses an optimal transmission path by means of switching between N array antennas and a transceiver is not suitable for forming adaptive beams.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a transceiver arrangement for a smart antenna system of a mobile communication base station for processing signals received from N array antennas with a single transceiver.
A receiving apparatus in accordance with the present invention comprises N array antennas, N means for down-converting each of the signals which are received from the N array antennas into a different frequency, respectively, means for combining the converted N signals into one signal, means for down-converting the combined signal into a base frequency band, means for converting the down-converted base frequency band signal into a digital signal, N digital dividing means for dividing the digital signal into N different signals and L beam forming modules for receiving one by one the N digital signals divided by each of N digital dividing means and for forming adaptive beam, wherein L is the number of subscribers.
A transmitting apparatus in accordance with the present invention comprises L beam forming modules having a respective weight for providing N different signals by multiplying each transmission signal by the weight, wherein L is the number of subscribers, N signal adders for adding N different signals provided by each of the beam forming modules, N digital modulators for up-converting the signal added by each of the signal adders into varying frequencies, respectively, a digital signal combiner for combining signals modulated frequency by the N digital modulators into a digital signal, a wide band digital-to-analog converter for converting the digital signal combined by the digital signal combiner into an analog signal, a wide-band transceiver for up-converting in the frequency the analog signal converted by the wide band digital-to-analog converter, a 1:N power divider for dividing an output signal of the wide-band transceiver into N signals, equally, N antenna front-end units (AFEUs), each of the AFEUS serving to convert one of the N signals divided by the 1:N power divider into a transmission frequency, and N array antennas for transmitting the signal from each of the antenna front-end units (AFEUs).
A transceiver arrangement of the present invention comprises N array antennas, N antenna front-end units for down-converting signals received from the N array antennas to N different intermediate band frequency or for up-converting N different intermediate band frequency signals into a radio transmission frequency, and then transmitting the up-converted radio transmission frequency via the N antennas, a N:1 power combiner for combining the down-converted N intermediate band frequency signals, a 1:N power divider for providing one of N different intermediate band frequency transmission signals to N antenna front-end units, respectively, a wide-band transceiver for down-converting a receiving signal combined by the N:1 power combiner into a base frequency band or for up-converting an analog transmission signal from the wide-band transceiver in the frequency to the 1:N power divider, a wide band analog-to-digital converter for converting a receiving signal down-converted by the wide-band transceiver into digital signals, N digital filters for dividing the converted digital signals into N different signals, a wide band digital-to-analog converter for converting a digital transmission signals into analog signals and for providing the converted analog signals to the wide-band transceiver, and beam forming module for forming an adaptive beam in receiving one of N digital receiving signals divided by the N digital filters in the receiving process or for multiplying each transmission signal by a weight and providing it with N signals divided in the transmitting process, wherein the number of the beam forming module is e
Cha Steve S.
Klauber & Jackson
Pihulic Daniel T.
Samsung Electronics Co,. Ltd.
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