Active Antenna System

Abstract

The present invention relates to an active antenna system. The system has a plurality of antennas (2) and a radio equipment (3) connected to the antennas (2) and being located adjacent to the antennas (2). This radio equipment (3) comprises for each antenna (2) a separate transceiver module (12).

What is claimed is: 
     
         1 . Method for compressing data using an active antenna system having a plurality of antennas for transmitting signals via a plurality of radio-channels, wherein the active antenna system comprises a radio equipment control and a radio equipment, wherein the radio equipment comprises an antenna module for each antenna, the method comprising:
 transmitting data only once between a radio equipment control unit and one of said antenna modules; and   duplicating and distributing the redundant data in between further antenna modules, wherein individual phase information is provided for each of said further antenna modules.   
     
     
         2 . Method according to  claim 1  wherein:
 the antenna modules each have a transceiver module, each transceiver module being connected to at least one antenna, 
 the radio equipment control unit has a hub being connected to the transceiver modules via an antenna interconnect, 
 wherein the hub is embodied for receiving base band signals via the antenna interconnect from the transceiver modules and to extract channel signals from the received base band signals. 
 
     
     
         3 . Method according to  claim 2 , wherein
 digital signals are transmitted via the antenna interconnect, wherein the digital signals of or for several antennas are jointly compressed.   
     
     
         4 . Method according to  claim 1  wherein:
 the antenna modules each comprise a transceiver module, each transceiver module being connected to at least one antenna, 
 each transceiver module comprises a switch matrix wherein at least one transceiver module is connected to the radio equipment control unit via an antenna interconnect. 
 
     
     
         5 . Method according to  claim 4 , wherein
 digital signals are transmitted via the antenna interconnect, wherein the digital signals of or for several antennas are jointly compressed.   
     
     
         6 . Method according to  claim 1 , wherein the radio equipment comprises an up-converter for converting a base band signal to a high frequency RF antenna signal for transmitting the antenna signal via the corresponding antenna, and a down-converter for converting a received high frequency RF antenna signal to a base band signal. 
     
     
         7 . Method according to  claim 1 ,
 wherein the radio equipment comprises a digital-to-analog converter for converting a digital signal received from the radio equipment control unit into an analog signal, and an analog-to-digital converter for converting an analog signal received by means of the antenna into a digital signal, wherein digital signals are transmitted via an antenna interconnect.   
     
     
         8 . Method according to  claim 1 ,
 wherein digital signals of or for several antennas are jointly compressed.   
     
     
         9 . Method according to  claim 8 ,
 wherein the jointly compressed digital signals are beamforming signals.   
     
     
         10 . Method according to  claim 1  wherein the radio equipment is connected to the antennas,
 wherein the radio equipment is located adjacent to the antennas and comprises for each antenna a separate transceiver module. 
 
     
     
         11 . Method according to  claim 1 , wherein
 a digital signal received from the radio equipment control unit is converted into an analog signal using a digital-to-analog converter of the radio equipment, and   an analog signal received by the antenna is converted into a digital signal using an analog-to-digital converter of the radio equipment.   
     
     
         12 . Method according to  claim 1 , wherein the radio equipment comprises an optical beam former chip and a photonic predistortion element. 
     
     
         13 . Method according to  claim 1  for further establishing a secure data connection using said active antenna system having a plurality of antennas for transmitting signals via a plurality of radio-channels, wherein the radio-channels are beamformed, comprising:
 scanning for a communication partner, 
 estimating the direction of arrival (DOA) of a recognized communication partner, 
 sub-dividing a signal s(t) containing certain data which are to be transmitted in several partial signals d(t), wherein the partial signals d(t) are distributed onto a certain number (N) of radio-channels. 
 
     
     
         14 . Method according to  claim 13 , further comprising the step of
 transmitting an encryption key with the signal s(t).   
     
     
         15 . Method according to  claim 1 , further comprising the step of
 calculating predistortion factors (w 1 , . . . , w N ) for compensating a distortion in the individual radio channels.   
     
     
         16 . Method according to  claim 15 , wherein weighting factors for inversely reproducing the radio channels (w 1 , . . . , w N ↔h −1   1 , . . . , h −1   N ) are calculated as the predistortion factors, and these weighting factors are combined with beam-forming parameters to a beam-forming matrix. 
     
     
         17 . Method according to  claim 1  for further establishing a secure data connection using said active antenna system, comprising:
 measuring certain physical parameters of the radio channels and 
 using the physical parameters for encrypting data to be exchanged between the active antenna system and the communication partner. 
 
     
     
         18 . Method according to  claim 17 , wherein
 the measured physical parameters are channel impulse coefficients.   
     
     
         19 . Method according to  claim 17 , wherein the physical parameters are transmitted with a signal s(t).