Interleaved antenna array configuration in a radio node

Abstract

An interleaved antenna array configuration in a radio node is disclosed. The antenna array includes a mixture of isolated and non-isolated antenna elements interleaved in each row and each column of the antenna array. Each isolated antenna element is only adjacent to one or two non-isolated antenna elements in each row and each column. Each non-isolated antenna element is only adjacent to one or two isolated antenna elements in each row and each column. By interleaving the isolated and non-isolated antenna elements in each row and column of the antenna array, it is possible to reduce a number of antenna isolators, thus helping to reduce cost and footprint of the radio node. Further, by using a combination of antenna isolators and simplified digital pre-distortion (DPD) actuators in association with the interleaved antenna array, the radio node is able to satisfy stringent radio frequency (RF) performance requirements.

1 . A radio node, comprising:
 an antenna array comprising:
 a plurality of isolated antenna elements and a plurality of non-isolated antenna elements disposed in a first number of rows and a second number of columns, wherein the plurality of isolated antenna elements and the plurality of non-isolated antenna elements are interleaved in each of the first number of rows and each of the second number of columns; and 
 a plurality of antenna isolators each coupled to a respective one of the plurality of isolated antenna elements; and 
 a plurality of non-isolated amplifier circuits each coupled to a respective one of the plurality of non-isolated antenna elements in the antenna array. 
   
     
     
         2 . The radio node of  claim 1 , wherein:
 each of the plurality of isolated antenna elements is adjacent to a respective one or two of the plurality of non-isolated antenna elements in each of the first number of rows and each of the second number of columns; and   each of the plurality of non-isolated antenna elements is adjacent to a respective one or two of the plurality of isolated antenna elements in each of the first number of rows and each of the second number of columns.   
     
     
         3 . The radio node of  claim 1 , further comprising a plurality of isolated amplifier circuits each coupled to a respective one of the plurality of antenna isolators, wherein the plurality of isolated amplifier circuits each comprises:
 an isolated power amplifier coupled to the respective one of the plurality of antenna isolators and adapted to amplify a respective radio frequency (RF) signal to generate a respective amplified RF signal for radiation via the respective one of the plurality of isolated antenna elements;   a digital-to-analog converter (DAC) coupled to the isolated power amplifier and adapted to receive and convert a respective digital signal into the respective RF signal; and   a digital pre-distortion (DPD) circuit coupled to the DAC and adapted to pre-distort the respective digital signal to reduce nonlinearity distortion in the respective amplified RF signal.   
     
     
         4 . The radio node of  claim 1 , wherein the plurality of non-isolated amplifier circuits each comprises:
 a non-isolated power amplifier coupled to the respective one of the plurality of non-isolated antenna elements, the non-isolated power amplifier adapted to amplify a respective RF signal to generate a respective amplified RF signal for radiation via the respective one of the plurality of non-isolated antenna elements;   a DAC coupled to the non-isolated power amplifier and adapted to receive and convert a respective digital signal into the respective RF signal; and   a simplified DPD circuit coupled to the DAC and adapted to pre-distort the respective digital signal based on a simplified dual-input power amplifier (DI-PA) DPD algorithm to reduce nonlinearity distortion in the respective amplified RF signal.   
     
     
         5 . The radio node of  claim 4 , wherein the antenna array is adapted to not include an antenna isolator between the non-isolated power amplifier and the respective one of the plurality of non-isolated antenna elements. 
     
     
         6 . The radio node of  claim 4 , wherein the simplified DI-PA DPD algorithm is determined for each of the plurality of non-isolated power amplifiers based on a respective indirect DI-PA input that is a function of up to four isolated antenna elements immediately surrounding a respective one of the plurality of non-isolated antenna elements coupled to the non-isolated power amplifier. 
     
     
         7 . The radio node of  claim 1 , further comprising:
 a second antenna array, the second antenna array comprising a plurality of second isolated antenna elements and a plurality of second non-isolated antenna elements disposed in the first number of rows and the second number of columns, wherein the plurality of second isolated antenna elements and the plurality of second non-isolated antenna elements are interleaved in each of the first number of rows and each of the second number of columns;   a plurality of second isolated amplifier circuits each coupled to a respective one of the plurality of second isolated antenna elements in the second antenna array; and   a plurality of second non-isolated amplifier circuits each coupled to a respective one of the plurality of second non-isolated antenna elements in the second antenna array.   
     
     
         8 . The radio node of  claim 7 , wherein:
 each of the plurality of second isolated antenna elements is adjacent to a respective one or two of the plurality of second non-isolated antenna elements in each of the first number of rows and each of the second number of columns; and   each of the plurality of second non-isolated antenna elements is adjacent to a respective one or two of the plurality of second isolated antenna elements in each of the first number of rows and each of the second number of columns.   
     
     
         9 . The radio node of  claim 7 , wherein the antenna array is stacked on the second antenna array, wherein:
 each of the plurality of isolated antenna elements in the antenna array is stacked on a respective one of the plurality of second non-isolated antenna elements in the second antenna array; and   each of the plurality of non-isolated antenna elements in the antenna array is stacked on a respective one of the plurality of second isolated antenna elements in the second antenna array.   
     
     
         10 . The radio node of  claim 7 , wherein the antenna array is stacked on the second antenna array, wherein:
 each of the plurality of isolated antenna elements in the antenna array is stacked on a respective one of the plurality of second isolated antenna elements in the second antenna array; and   each of the plurality of non-isolated antenna elements in the antenna array is stacked on a respective one of the plurality of second non-isolated antenna elements in the second antenna array.   
     
     
         11 . The radio node of  claim 1 , wherein:
 the plurality of isolated antenna circuits and the plurality of non-isolated antenna circuits in the antenna array are adapted to radiate in a first polarization; and   the plurality of second isolated antenna circuits and the plurality of second non-isolated antenna circuits in the second antenna array are adapted to radiate in a second polarization different from the first polarization.   
     
     
         12 . The radio node of  claim 1  is adapted to operate as a base station in a radio network. 
     
     
         13 . The radio node of  claim 1  is adapted to operate as a wireless device in a radio network. 
     
     
         14 . A method for configuring an antenna array in a radio node, comprising:
 disposing a plurality of isolated antenna elements and a plurality of non-isolated antenna elements in a first number of rows and a second number of columns of the antenna array such that the plurality of isolated antenna elements and the plurality of non-isolated antenna elements are interleaved in each of the first number of rows and each of the second number of columns;   coupling a plurality of antenna isolators to the plurality of isolated antenna elements in the antenna array, respectively; and   coupling each of a plurality of non-isolated amplifier circuits to a respective one of the plurality of non-isolated antenna elements in the antenna array.   
     
     
         15 . A method for operating a radio node, the radio node comprising an antenna array that comprises a plurality of isolated antenna elements and a plurality of non-isolated antenna elements that are interleaved in each row and each column, the method comprising:
 performing a first type of digital pre-distortion (DPD) to pre-distort a first digital signal;   converting the pre-distorted first digital signal into a first radio frequency (RF) signal;   amplifying the first RF signal to generate a first amplified RF signal;   providing the first amplified RF signal to a respective one of the plurality of isolated antenna elements;   performing a second type of DPD to pre-distort a second digital signal;   converting the pre-distorted second digital signal into a second RF signal;   amplifying the second RF signal to generate a second amplified RF signal; and   providing the second amplified RF signal to a respective one of the plurality of non-isolated antenna elements.   
     
     
         16 . The method of  claim 15 , wherein the first type of DPD is a single-input single-output (SISO) DPD. 
     
     
         17 . The method of  claim 15 , wherein the second type of DPD is a simplified dual-input power amplifier (DI-PA) DPD.