carrier is allocated for covering hot spot areas supporting highly asymmetric traffic with relatively low mobility following the investigation of tdd fdd underlay as described by harald haas and gordon povey u201c capacity analysis of a tdd underlay applicable to umts u201d in proceeding of pimr99 pp 167 171 the tdd bs should ideally located to at a distance of about half the fdd cell radius accordingly it is reasonable that three tdd cells cluster are located at fdd macro cell boundary as illustrated in fig2 because fdd macro cell bs covers the center zone near to the bs by transmitting higher bs power level note that this location is dependent on the tdd and fdd cell sizes in general the sectorization technique is used to obtain the frequency reuse efficiency in cellular communication systems thereby increasing in capacity the cell by dividing one cell into several sectors therefore with this principle the sectored tdd and fdd hierarchical cellular system can guarantee capacity enhancement fig2 illustrates a three tdd cell cluster example however it should be noted that more than three tdd cells can gather with much smaller radius thus not every tdd bss can keep a reasonable distance from the fdd bs unless tdd cells cluster are located as like in fig2 the present.