Fractional frequency reuse deployment method for wireless system

Abstract

In a wireless communications system each base stations communicates with respective subscriber devices within a geographical area of a wireless cell served by a respective base station. The geographical area of the wireless cell comprises a geographical central area and a geographical edge area. More than a third of all transmission resources available to the serving base station are available for communicating with the subscriber devices located within the geographical edge area of the wireless cell. At least one of the transmission resources available for communicating with each of the subscriber devices currently located within the geographical edge area of the wireless cell is other than any of the transmission resources available for communicating with subscriber devices currently located within geographical edge areas of wireless cells having a geographical edge area that is adjacent to the edge area of the wireless cell at which the subscriber device is located.

1 . A method of reusing transmission resources available in a 3-sector cell of a cellular network, comprising:
 electing three transmission resources for communication between a base station and mobile user devices within the 3-sector cell, each sector being adjacent to the two other sectors;   associating two of the elected transmission resources with each sector, each sector having one transmission resource in common with one of its adjacent sectors and one transmission resource in common with its other adjacent sector, reusing each transmission resource in two sectors;   establishing communication between the base station and the mobile user devices in each sector using one of the two transmission resources associated with the respective sector, based on the location of the mobile user device in the respective sector.   
     
     
         2 . A method as claimed in  claim 1 , wherein the transmission resources include:
 a) a frequency channel,   b) a set of frequency channels,   c) a set of frequency subchannels,   d) a time slot,   e) a set of time slots, or   f) any time-frequency slot combination, and combinations thereof.   
     
     
         3 . A method as claimed in  claim 2 , wherein when the transmission resources include CDMA spreading codes. 
     
     
         4 . A method as claimed in  claim 2 , wherein the transmission resources include antenna polarization modes. 
     
     
         5 . A method as claimed in  claim 1 , wherein the cellular network is a frequency division multiplexed network or a time division duplexed cellular network. 
     
     
         6 . A method of reusing transmission resources available in a cellular network of multi-sector cells, comprising:
 electing a first set of transmission resources and a second set of transmission resources from the transmission resources available in the network;   associating transmission resources in the first set of transmission resources to sectors of a first multi-sector cell;   associating transmission resources in the second set of transmission resources to sectors of a second multi-sector cell including assigning transmission resources to sectors of the second multi-sector cell that are adjacent with sectors of the first multi-sector cell, wherein the transmission resources assigned to each sector of the second multi-sector cell that are adjacent with sectors of the first multi-sector cell are different than the transmission resources assigned to the adjacent sector of the first multi-sector cell; and   establishing wireless communication in the first multi-sector cell using, in each sector of the first multi-sector cell, a transmission resource assigned from the first set of transmission resources, and establishing wireless communication in the second multi-sector cell using, in each sector of the second multi-sector cell, a transmission resource assigned from the second set.   
     
     
         7 . A method as claimed in  claim 6 , wherein a number of transmission resources in the first set are reused in spaced apart sectors of the first multi-sector cell, when the number of transmission resources in the first set is less that the number of sectors of the first multi-sector cell. 
     
     
         8 . A method as claimed in  claim 6 , wherein the transmission resources in the first set are reused in spaced apart sectors of the second multi-sector cell. 
     
     
         9 . A method as claimed in  claim 6 , further comprising establishing a third set of transmission resources from the transmission resources available in the network, the third set having a first transmission resource in common with the first set and a second transmission resource in common with the second set. 
     
     
         10 . A method as claimed in  claim 9 , further comprising
 establishing wireless communication in a third multi-sector cell which is adjacent to the first and second multi-sector cells, using in each sector of the third multi-sector cells a transmission resource from the third set, wherein,   the transmission resources in sectors of the first multi-sector cell that are adjacent with the sectors of the third multi-sector cell use transmission resources which are different than the transmission resources used in the adjacent sectors of the third multi-sector cell; and   the transmission resources in sectors of the second multi-sector cell that are adjacent with the sectors of the third multi-sector cell use transmission resources which are different than the transmission resources used in the adjacent sectors of the third multi-sector cell.   
     
     
         11 . A method as claimed in  claim 10 , wherein the third set of transmission resources reuses a transmission resource from the first set. 
     
     
         12 . A method as claimed in  claim 10 , wherein the second set of transmission resources reuses a transmission resource from the first set of transmission resources and the third set of transmission resources reuses a transmission resource from the first set. 
     
     
         13 . A method as claimed in  claim 10 , wherein the second set of transmission resources reuses a transmission resource from the first set of transmission resources and the third set of transmission resources reuses a set of transmission resources from the second set. 
     
     
         14 . A method as claimed in  claim 10 , wherein the transmission resource includes:
 a) a frequency channel,   b) a set of frequency channels,   c) a set of frequency subchannels,   d) a time slot,   e) a set of time slots, or   f) any time-frequency slot combination, and combinations thereof.   
     
     
         15 . A method as claimed in  claim 10 , wherein the number of sectors in the multi-sector cells is N and the number of transmission resources available in the network is N. 
     
     
         16 . A method as claimed in  claim 13 , wherein the first, second and third set of transmission resources use N transmission resources, and the number of transmission resources reused in each of the first, second and third set is N/3. 
     
     
         17 . A method as claimed in  claim 10 , wherein the number of sectors in the multi-sector cells is N and the number of transmission resources available in the network is M>N. 
     
     
         18 . A method as claimed in  claim 15 , wherein the first, second and third set of transmission resources use M transmission resources, and the number of transmission resources reused in each of the first, second and third set is at least N/3. 
     
     
         19 . A method of reusing transmission resources in a cellular network of multi-sector cells, comprising:
 establishing a plurality of groups of transmission resources, a group of transmission resources reusing a transmission resource from another group of the plurality of groups of transmission resources;   selecting a first set of groups from the groups of transmission resources for a first multi-sector cell and selecting a second set of groups from the groups of transmission resources for a second multi-sector cell adjacent to the first multi-sector cell; and   associating each group of transmission resources in the first set with a sector of the first multi-sector cell and associating each group of transmission resources in the second set with a sector of the second multi-sector cell, wherein,
 each group of transmission resources from the first set is reused in the most spaced apart sectors of the first multi-sector cell and each group of transmission resources from the second set is reused in the most spaced apart sectors of the second multi-sector cell, and 
 a group of transmission resources from the first set used in a first sector of the first multi-sector cell is different from a group of transmission resources from the second set used in a sector of the second multi-sector cell that is adjacent to the first sector. 
   
     
     
         20 . A method as claimed in  claim 19 , wherein the groups of transmission resources reuse at least ⅓ of the transmission resources from the transmission resources in other groups. 
     
     
         21 . A method as claimed in  claim 19 , wherein the second set includes at least ⅓ of the groups in the first set. 
     
     
         22 . A method as claimed in  claim 19 , wherein the number of transmission resources in a group is half the number of sectors in a multi-sector cell. 
     
     
         23 . A method as claimed in  claim 19 , wherein a transmission resource includes:
 a) a frequency channel,   b) a set of frequency channels,   c) a set of frequency subchannels,   d) a time slot,   e) a set of time slots, or   f) any time-frequency slot combination, and combinations thereof.   
     
     
         24 . A method as claimed in  claim 19 , wherein when a mobile user device is about to move from a sector served by a first base station to a sector served by a second base station, the first base station informs the second base station and the mobile user device of at least one particular transmission resource to be used for conducting a handover procedure. 
     
     
         25 . A method as claimed in  claim 24 , wherein the particular transmission resource used for conducting the handover procedure is a transmission resource used in a first set and second set. 
     
     
         26 . A method as claimed in  claim 24 , wherein the particular transmission resource used for conducting the handover procedure is different from any transmission resource used in a first set and second set.