A certain area is covered by a cellular radio system with 168 cells and a cluster size N. 336 voice channels are available for the system. Users are uniformly distributed over the area covered by the cellular system. Assume the average call length is 72 seconds, and each user averages 3 calls per hour. Blocked calls are cleared and the designated blocking probability is 0.5%. a) Determine the maximum number of users that can be served by the system for cluster size N=4. Repeat for cluster size N=12. b) Determine the maximum carried traffic per cell if cluster size N=7 is used. Repeat for cluster size N= 19. Discuss about the result of this case.