A wireless cellular system is planned to cover a straight highway with base stations placed along it. Each base station has 40 channels at its disposal and employs omni-directional antennas. A...

A wireless cellular system is planned to cover a straight highway with base stations placed along it. Each base station has 40 channels at its disposal and employs omni-directional antennas. A modulation and coding scheme requiring 19 dB SIR is employed. The required area capacity is 10 mobiles/km for a channel assignment failure rate of 2%. Assume that the propagation loss increases with the fourth power of the distance. a) Assume a shadow fading channel with a log-normal standard deviation σ = 6 dB. The fading correlation is angle-dependent and is at its maximum when the angle between the links is zero. Determine the outage probability. b) How many fewer base stations are needed if we use directional antennas (radiating only in one direction along the road) instead of omni-directional antennas (radiating in all directions)?