Patent ID: 7372829

Claim:
Method of performing a migration from a first cell-plan to a second cell plan, the first cell plan comprises cells having four 90° sectors to each of which one of four orthogonal channels (a, b; A, B) are allocated; the first cell plan includes four specific cell types ( 6 , 7 , 8 , 9 ) which are periodically repeated over the first cell plan, each cell type having a specific allocation of channels (a, b; A, B) to specific sectors; wherein a particular channel is allocated to an even number of sectors per cell; no same channel (a, b; A, B) is allocated to corresponding sectors (*) - that is, sectors having a given orientation - of all four cell types; no same channel (a, b; A, B) is allocated to adjacent sectors (X) of any cell type; no same channel (a, b; A, B) is allocated to a particular sector of any given cell type and an adjacent sector (#) of any other cell type to the corresponding sector of the particular sector found in the directions of the sector boundaries of the particular sector; the method comprising the step of splitting a given pair of corresponding 90° sectors of the first and third ( 6 , 8 ) cell type, respectively, or of the second and fourth ( 7 , 9 ) cell type, respectively, into two pairs ( 13 , 14 ; 15 , 16 ) of corresponding split 45° sectors; and re-allocating channels by interchanging channels for one ( 13 , 14 ) of said two pairs of corresponding split sectors while keeping the channel allocation for the other ( 15 , 16 ) of said two pairs of split sectors according to the first cell plan, the first and third ( 6 , 7 ) types of cells being selected such that any splitting and re-allocation can be performed such that after the re-allocation, adjacent sectors of a given cell have different channels.