Distributed antenna system including crest factor reduction module disposed at optimum position

Abstract

A distributed antenna system includes a plurality of head-end units for each receiving mobile communication signals from at least one corresponding base station, a hub unit communicatively coupled to the plurality of head-end units, and a plurality of remote units communicatively coupled to the hub unit, wherein the hub unit configured to distribute the mobile communication signals received from each of the plurality of head-end units to the plurality of remote units, wherein each of the plurality of remote units is remotely disposed to transmit the distributed mobile communication signals to a terminal in service coverage, and wherein the hub unit includes a mixing processing stage configured to perform digital mixing processing on the mobile communication signals respectively received from the plurality of head-end units, and a crest factor reduction (CFR) module disposed posterior to the mixing processing stage, with respect to a signal transmission direction.

What is claimed is: 
     
         1 . A distributed antenna system, comprising:
 a plurality of head-end units each configured to receive mobile communication signals from at least one corresponding base station;   a hub unit communicatively coupled to the plurality of head-end units; and   a plurality of remote units communicatively coupled to the hub unit,   wherein the hub unit configured to distribute the mobile communication signals received from each of the plurality of head-end units to the plurality of remote units,   wherein each of the plurality of remote units is remotely disposed to transmit the distributed mobile communication signals to a terminal in a service coverage, and   wherein the hub unit includes a mixing processing stage configured to perform digital mixing processing on the mobile communication signals respectively received from the plurality of head-end units, and a crest factor reduction (CFR) module disposed posterior to the mixing processing stage with respect to a signal transmission direction.   
     
     
         2 . The distributed antenna system of  claim 1 , wherein the plurality of head-end units receive mobile communication signals in at least one mobile communication service band from the at least one corresponding base station, convert the received mobile communication signals into mobile communication signals in a baseband or intermediate frequency (IF) band, perform digital signal conversion on the band-converted mobile communication signals, and transmit the digital-converted mobile communication signals to the hub unit. 
     
     
         3 . The distributed antenna system of  claim 2 , wherein the plurality of head-end units receive different mobile communication signals,
 wherein the mixing processing stage includes a signal summer configured to digitally sum different mobile communication signals respectively from the plurality of head-end units, and   wherein the CFR module is disposed posterior to the signal summer.   
     
     
         4 . The distributed antenna system of  claim 2 , wherein the mixing processing stage includes a signal summer configured to digitally sum signals in the same mobile communication service band among the mobile communication signals respectively received from the plurality of head-end units, and
 wherein the CFR module is disposed posterior to the signal summer.   
     
     
         5 . The distributed antenna system of  claim 4 , wherein the hub unit further includes a band separator configured to receive mobile communication signals respectively received from the plurality of head-end units and separate signals corresponding to a specific mobile communication service band among the received mobile communication signals. 
     
     
         6 . The distributed antenna system of  claim 5 , wherein the signal summer performs sub-band signal summing on different sub-band signals in the same mobile communication service band among the signals band-separated by the band separator, and digitally re-sum signals for each mobile communication service band, which obtained by performing the sub-band signal summing. 
     
     
         7 . The distributed antenna system of  claim 2 , wherein the plurality of head-end units is communicatively coupled to the at least one corresponding base station to receive signals for each sector in the same mobile communication service band,
 wherein the mixing processing stage includes a signal swapper configured to perform swapping on the signals for each sector, respectively received from the plurality of head-end units, and   wherein the CFR module is disposed posterior to the signal swapper.   
     
     
         8 . A distributed antenna system, comprising:
 a head-end unit configured to receive mobile communication signals from a plurality of base stations; and   at least one remote unit communicatively coupled to the head-end unit, the at least one remote unit receiving the mobile communication signals from the head-end unit, the at least one remote unit being remotely disposed to transmit the mobile communication signals to a terminal in service coverage,   wherein the head-end unit includes a mixing processing stage configured to perform digital mixing processing on the mobile communication signals respectively received from the plurality of base stations, and a CFR module disposed posterior to the mixing processing stage with respect to a signal transmission direction.   
     
     
         9 . The distributed antenna system of  claim 8 , wherein the head-end unit configured to receive mobile communication signals in at least one mobile communication service band from the plurality of base stations, convert the received mobile communication signals into mobile communication signals in a baseband or IF band, and perform digital signal conversion on the band-converted mobile communication signals. 
     
     
         10 . The distributed antenna system of  claim 9 , wherein the head-end unit configured to receive different mobile communication signals from the plurality of base stations,
 wherein the mixing processing stage includes a signal summer configured to digitally sum the different mobile communication signals received from the plurality of base stations, and   wherein the CFR module is disposed posterior to the signal summer.   
     
     
         11 . The distributed antenna system of  claim 9 , wherein the mixing processing stage includes a signal summer configured to digitally sum signals in the same mobile communication service band among the mobile communication signals respectively received from the plurality of base stations, and
 wherein the CFR module is disposed posterior to the signal summer.   
     
     
         12 . The distributed antenna system of  claim 11 , wherein the head-end unit further includes a band separator configured to receive mobile communication signals respectively transmitted from the plurality of base stations and separate only signals corresponding to a specific mobile communication service band among the received mobile communication signals. 
     
     
         13 . The distributed antenna system of  claim 12 , wherein the signal summer performs sub-band signal summing on different sub-band signals in the same mobile communication service band among the signals band-separated by the band separator, and digitally re-sum signals for each mobile communication service band, which obtained by performing the sub-band signal summing. 
     
     
         14 . The distributed antenna system of  claim 9 , wherein the head-end unit is communicatively coupled to the plurality of base stations to receive signals for each sector in the same mobile communication service band,
 wherein the mixing processing stage includes a signal swapper configured to perform swapping on the signals for each sector, respectively received from the plurality of base stations, and   wherein the CFR module is disposed posterior to the signal swapper.   
     
     
         15 . A distributed antenna system, comprising:
 at least one head-end unit configured to receive mobile communication signals from a plurality of base stations; and   at least one remote unit communicatively coupled to the at least one head-end unit, the at least one remote unit receiving the mobile communication signals from the at least one head-end unit, the at least one remote unit being remotely disposed to transmit the mobile communication signals to a terminal in a service coverage,   wherein the at least one remote unit includes a signal summer configured to digitally sum the mobile communication signals transmitted from the at least one head-end unit, and a CFR module disposed posterior to the signal summer, with respect to a signal transmission direction.   
     
     
         16 . The distributed antenna system of  claim 15 , wherein the at least one remote unit further includes a band separator configured to receive mobile communication signals transmitted from the at least one head-end unit and separate only signals corresponding to a specific mobile communication service band among the received mobile communication signals. 
     
     
         17 . The distributed antenna system of  claim 16 , wherein the signal summer performs digital signal summing on different sub-band signals in the same mobile communication service band among the signals band-separated by the band separator.