uler is to avoid inter-cell interference at the cell edge. The cell edge data rate is heavily affected by the interference from the adjacent cells due to frequency reuse. If the scheduler can avoid inter-cell interference, the cell edge data rates can be improved (see Figure 7.2). That is one of the main motivations for developing advanced packet scheduling solution. The FSS is the main component in the packet scheduler, and we will analyse the FSS solution in more detail. First of all, the scheduler needs to obtain information about the amount of inter- cell interference in the frequency domain. The channel quality indicator (CQI) reporting from UEs can be configured in the frequency domain SO that UE reports CQI value, for example, for Frequency f1 Frequency f1 BTS A BTS B High data rate Low data rate close to BTS at cell edge Figure 7.2 Inter-cell interference impacts cell edge throughputs Small Cell Interference Management Frequency High CQI Low CQI High CQI Cell A Low CQI Cell B High CQI = Resources for UE A = Unallocated resources Figure 7.3 Obtaining inter-cell interference information with CQI feedback every six PRBs. Low CQI value indicates that UE receives high inter-cell interference while high CQI value indicates that UE receives only low inter-cell interference. CQI reporting also provides information about signal fading. The CQI reporting is illustrated in Figure 7.3. Cell A uses part of its PRBs for the data transmission to UE A while part of its PRBs are empty. The adjacent Cell B schedules data for UE B which receives some inter-cell interference from Cell A. UE B provides CQI reports to Cell B and these reports provide information about inter-cell interference in the frequency domain. The CQI reports can be utilized by Cell B in FSS solution in Figure 7.4. Assume that there are two UEs in Cell B: UE B at the cell edge experiencing inter-cell interference from Cell A and UE C which is located close to Cell B and experiencing no inter-cell interference. Cell B can schedule data to UE B in those PR