Patent ID: 8442002

Claim:
A method for operating a multi-cell radio system, comprising a plurality of base stations, wherein different frequency reuse factors are used within different reuse zones of one cell by means of a fractional frequency reuse (FFR) scheme, comprising the following steps: allocating a size or resource to the different reuse zones; and allocating users into different reuse zones, wherein a higher network layer loads a size or resource allocation information from a database, and then informs each base station what size or resource has been allocated to them, respectively, wherein at least one base station allocates users to different reuse zones, wherein said at least one base station asks users to report metrics, wherein the metrics include the preamble carrier to interference and noise ratio (CINR) of different zones, wherein the users report the metrics to the respective base stations, wherein said the at least one base station allocates the users to different zones according to the reported values of metrics, and wherein the user allocating step on the basis of two different reuse zones—zone one with a lower reuse factor and zone two with a higher reuse factor—comprises: (a) calculating the metric r i =SINR 1 /SINR 2 , where SINR 1 is the estimate of the average CINR over all subcarriers of the preamble except the guard subcarriers and the DC subcarriers and SINR 2 is the estimate of the average CINR over only the modulated subcarriers for the preamble, (b) classifying the users in two different groups, depending on the relation r i <Th (group one) or r i ≧Th (group two), where Th is a definable threshold, (c) sorting users in group two by SINR 2 in descending order, then allocating these users to zone two from the user with highest SINR 2 , then, if all users in group two have been allocated, selecting user in group one with highest SINR 2 and allocating it to zone two till all the resource in zone two has been used and, if there are any users which have not been allocated resource, classifying them to group one, and (d) sorting users in group one by SINR 1 in descending order, and then allocating them to zone one from the user with highest SINR 1 until all users have been allocated resource or all the resource has been used up.