14-el-a3 signals and communications (30 points) in a cellular system, a 200 khz bandwidth signal is transmitted at a carrier frequency of 937 mhz. the base station sends the signal using an isotropic antenna over a cell of question 1: 3.8 km radius a) determine the mobile receiver antenna gain, grxdb in db, required to obtain a (15 points) maximum attenuation amar of 90 db in the cell. b) if the mobile receivers are uniformly distributed in the cell, then the average attenuation can be expressed as: 2 rdmar a(r)rdrdp where dmax is the maximum distance maximale and a(r) is the attenuation as a function of distance r, expressed in meters, between the base station and a mobile receiver. what is the receive antenna gain, grxdb in db, needed to get an average attenuation of 90 db?