ss( Lbr) 5.0 dB (SD,HSB) Feeder losses (Lc1) 4.2 dB Connector Loss (Lc2) 4.2 dB Antenna gains(Gal and Ga2) 47.3 dBi Hop loss in non-faded state (Lho) 60.3 dB Received unfaded power (Prx) -33.3 dBm Receiver threshold power (Prxth) -76.5 dBm ( at BER 10 -3) Flat fading margin (M) 43.2 dB Calculated flat outage time ( Pfm) 0.0283 % Total outage time (non-diversity) p 0.0283 % Annual unavailability due to rain 0.0003 % With space diversity : Diversity antenna diameter (Dd) 3.7 m Antenna gain (Gd) 47.3 dBi Antenna spacing (s) 10.0 m Diversity improvement (1fm) 3.4 DETAILED TRANSMISSION NETWORK PLANNING 3.4.1 Frequency Planning A microwave link is rarely situated in an isolated environment. There are usually many microwave links in a given region, of the same and/or different network operators. Then there are links that are not related to cellular networks radiating frequencies that may cause problems in these networks, e.g. radar systems. Owing to the presence of SO many different sources of radiation in a region, it is very important to construct correct frequency plans TRANSMISSION NETWORK PLANNING AND OPTIMISATION for one's own network. The process usually starts with application for a frequency being made to the local governing bodies. Owing to congestion, the number of frequency bands given to a cellular operator are usually less than desired, making the need for an efficient (i.e. interference-free) frequency plan even more necessary. Before we go into frequency planning, let us see the various kinds of interferences and sources of interference that may exist in a network: intra-system interference (noise, imperfections, etc.) inter-channel interference (adjacent/co-channel, etc.) inter-hop interference (front-to-back, over-reach) external interference (other systems, radar, etc.). For frequency planning in the microwave network, inter-channel interference and inter- hop interference are of utmost important for transmission planners. Intra-system interfer- ence is caused by noise generated within the system and 