Methods and systems to mitigate inter-cell interference

Abstract

The present invention provides methods and devices for mitigating inter-cell interference in communication environments having a plurality of cells. In some embodiments, a time-frequency transmission resource that includes multiple sub-carriers over multiple OFDM symbol intervals is partitioned into a first zone and a second zone. In the first zone, transmissions are transmitted on at least one frequency sub-band which is common to all of the plurality of cells. In the second zone, transmissions are transmitted on at least one frequency sub-band which is used by less than all of the plurality of cells, so as to mitigate inter-cell interference. In some embodiments, in the first zone transmissions are transmitted using a transmission power which is common to all of the plurality of cells and in the second zone transmissions are transmitted using a transmission power which is used by less than all of the plurality of cells so as to mitigate inter-cell interference.

1 .- 37 . (canceled) 
     
     
         38 . A radio device for use in at least one of a plurality of radio cell areas, the radio device comprising:
 two or more antenna each coupled to a respective receive path signal processing component that is configured to process time-frequency signals received by the respective antenna over a respective wireless transmission medium;   a symbol data recovery unit operatively coupled to the respective receive path signal processing components of the two or more antenna;   wherein the received time-frequency signals are each in a form of two or more transmission blocks each configured as part of a time-frequency grid having respective minimum and maximum frequency boundaries in a row direction and having respective minimum and maximum temporal boundaries in a column direction, the two or more transmission blocks having a same number of matrix columns between the minimum and maximum frequency boundaries, the two or more transmission blocks being of equal temporal lengths and having a same number of matrix rows between their respective minimum and maximum temporal boundaries, where intersections of respective rows and columns occur at respective grid locations;   wherein each respective receive path signal processing component of the radio device includes a respective pilot symbol extractor, a respective channel estimator and a respective channel reconstructor, the channel reconstructor being configured to determine current response characteristics of its respective wireless transmission medium based on a plurality of pilot symbols that partially populate the two or more transmission blocks;   wherein the symbol data recovery unit recovers symbol data based on less than all of the grid locations of the two or more transmission blocks of each of the received time-frequency signals, the remainder of the grid locations of the two or more transmission blocks being scattered pilot symbol locations and at least one of control data locations and null symbol locations.   
     
     
         39 . The radio device of  claim 38  wherein:
 the scattered pilot symbol locations of at least two of the two or more antenna each abuts in its respective matrix row at least one of a null symbol location and a control data location. 
 
     
     
         40 . The radio device of  claim 39  wherein:
 the scattered pilot symbol locations of said at least two of the two or more antenna each abuts in its respective matrix row a respective null symbol location where the matrix column of the respective null symbol location is used within another of the plurality of radio cell areas as at least one of a symbol data location, and a control data location. 
 
     
     
         41 . The radio device of  claim 39  wherein:
 the scattered pilot symbol locations of said at least two of the two or more antenna are adjacent to one another in a same matrix row and are adjacent in that same matrix row to an additional one or more null symbol locations. 
 
     
     
         42 . The radio device of  claim 41  wherein:
 the additional one or more null symbol locations of said same matrix row are adjacent to one or more control data location. 
 
     
     
         43 . The radio device of  claim 41  wherein:
 there are no symbol data locations in said same matrix row. 
 
     
     
         44 . The radio device of  claim 43  wherein:
 said same matrix row constitutes a topmost matrix row for the of two or more transmission blocks. 
 
     
     
         45 . The radio device of  claim 39  wherein:
 the channel reconstructor is configured to determine current response characteristics of its respective wireless transmission medium for less than all the matrix columns based on said scattered pilot symbol locations of the at least two of the two or more antenna that each abuts in its respective matrix row at least one of a null symbol location and a control data location. 
 
     
     
         46 . The radio device of  claim 38  wherein:
 the radio device is a mobile one transportable between said at least one of the plurality of radio cell areas and another of the radio cell areas and operative in both of the radio cell areas. 
 
     
     
         47 . The radio device of  claim 38  and further comprising:
 a transmit section configured to transmit signals to a respective base station of the at least one of a plurality of radio cell areas; 
 wherein the signals transmitted to the respective base station include channel control information provided by way of one or more of control data locations of a same time-frequency grid as used by the received time-frequency signals. 
 
     
     
         48 . The radio device of  claim 47  wherein the included channel control information includes Channel Quality information (CQI) derived from the received time-frequency signals. 
     
     
         49 . A method for use in a radio device that is usable in at least one of a plurality of radio cell areas, where the radio device has two or more antenna each coupled to a respective receive path signal processing component that is configured to process time-frequency signals received by the respective antenna over a respective wireless transmission medium, where the radio device further has a symbol data recovery unit operatively coupled to the respective receive path signal processing components of the two or more antenna, wherein the received time-frequency signals are each in a form of two or more transmission blocks each configured as part of a time-frequency grid having respective minimum and maximum frequency boundaries in a row direction and having respective minimum and maximum temporal boundaries in a column direction, the two or more transmission blocks having a same number of matrix columns between the minimum and maximum frequency boundaries, the two or more transmission blocks being of equal temporal lengths and having a same number of matrix rows between their respective minimum and maximum temporal boundaries, where intersections of respective rows and columns occur at respective grid locations;
 wherein each respective receive path signal processing component of the radio device includes a respective pilot symbol extractor, a respective channel estimator and a respective channel reconstructor;   the method comprising:
 using the respective channel reconstructor of at least one of receive path signal processing components to determine current response characteristics of its respective wireless transmission medium based on a plurality of pilot symbols that partially populate the two or more transmission blocks of the received time-frequency signals of the corresponding at least one receive path signal processing component; 
 using the respective symbol data recovery unit of the radio device to recover symbol data based on less than all of the grid locations of the two or more transmission blocks of each of the received time-frequency signals, where the remainder of the grid locations of the two or more transmission blocks are constituted by scattered pilot symbol locations and at least one of control data locations and null symbol locations. 
   
     
     
         50 . The method of  claim 49  wherein:
 the scattered pilot symbol locations of at least two of the two or more antenna each abuts in its respective matrix row at least one of a null symbol location and a control data location. 
 
     
     
         51 . The method of  claim 50  wherein:
 the scattered pilot symbol locations of said at least two of the two or more antenna each abuts in its respective matrix row a respective null symbol location where the matrix column of the respective null symbol location is used within another of the plurality of radio cell areas as at least one of a symbol data location, and a control data location. 
 
     
     
         52 . The method of  claim 50  wherein:
 the scattered pilot symbol locations of said at least two of the two or more antenna are adjacent to one another in a same matrix row and are adjacent in that same matrix row to an additional one or more null symbol locations. 
 
     
     
         53 . The method of  claim 52  wherein:
 the additional one or more null symbol locations of said same matrix row are adjacent to one or more control data location. 
 
     
     
         54 . The method of  claim 50  wherein:
 there are no symbol data locations in said same matrix row. 
 
     
     
         55 . The method of  claim 50  wherein:
 said same matrix row constitutes a topmost matrix row for the of two or more transmission blocks. 
 
     
     
         56 . A multi-cell wireless communication system comprised of plural base stations with at least one base station for each respective cell area of the system and comprised of plural mobile radio devices each configured for use in at least one of the cell areas, where at least one of the radio devices comprises:
 two or more antenna each coupled to a respective receive path signal processing component that is configured to process time-frequency signals received by the respective antenna over a respective wireless transmission medium;   a symbol data recovery unit operatively coupled to the respective receive path signal processing components of the two or more antenna;   wherein the received time-frequency signals are each in a form of two or more transmission blocks each configured as part of a time-frequency grid having respective minimum and maximum frequency boundaries in a row direction and having respective minimum and maximum temporal boundaries in a column direction, the two or more transmission blocks having a same number of matrix columns between the minimum and maximum frequency boundaries, the two or more transmission blocks being of equal temporal lengths and having a same number of matrix rows between their respective minimum and maximum temporal boundaries, where intersections of respective rows and columns occur at respective grid locations;   wherein each respective receive path signal processing component of the radio device includes a respective pilot symbol extractor, a respective channel estimator and a respective channel reconstructor, the channel reconstructor being configured to determine current response characteristics of its respective wireless transmission medium based on a plurality of pilot symbols that partially populate the two or more transmission blocks;   wherein the symbol data recovery unit recovers symbol data based on less than all of the grid locations of the two or more transmission blocks of each of the received time-frequency signals, the remainder of the grid locations of the two or more transmission blocks being scattered pilot symbol locations and at least one of control data locations and null symbol locations; and   wherein each cell area uses a grid matrix having respective different grid locations for its pilot symbols.   
     
     
         57 . The multi-cell wireless communication system of  claim 56  wherein:
 the respective scattered pilot symbol locations used by the grid matrices of at least two adjacent ones of the cell areas each abuts in its respective matrix row at least one of a null symbol location and a control data location.