In cellular mobile communication, since there will be conversation in progress in case of handover calls, GOS for them should be less than that for newly originating calls. Basically, there are three channel assignment schemes, fixed, dynamic & hybrid channel assignment schemes for handling newly originating and handover calls. In this study, capacity design for cellular mobile network in area inside ring road in Kathmandu valley has been done according to the findings of data collection and analysis of mobile communication service being provided by Nepal Telecom. Capacity planning has been done with GOS equal to 2% for newly originating calls and 1% for handover calls. In addition to capacity planning, efficient channel assignment scheme in terms of blocking and throughput has been evaluated with optimal utilization of the designed capacity for getting minimum blocking for both types of calls maintaining the blocking for handover calls always less than that for newly originating calls. The simulated values of GOS & throughput for all channel assignment schemes at different penetration have been compared and hybrid channel assignment scheme has been found to be most efficient.