nd the receiver. The other required parameters are the transmission power, antenna gain, cable losses, receiver sensitivity and margins, as shown in Figure 2.8. Radio Network Planning and Optimisation path loss path loss Tx power Rx sensitivity cable loss cable loss combiner loss Rx sensitivity Tx power Figure 2.8 Link budget parameters When defining the cell coverage area, the aim is to balance the uplink and downlink powers. The links are calculated separately and are different from the transmission powers. The BTS transmission power is higher than the MS transmission power and therefore the reception of the BTS needs to have high sensitivity. The other differences in calculations between uplink and downlink are explained later. The parameter that is the same for both downlink and uplink calculations is the propagation loss. The radio signal experiences the same path loss when travelling from the BTS to the MS as from the MS to the The GSM link budget parameters are explained in the following before proceeding to the calculations in more detail: BTS sensitivity is specified on the ETSI GSM recommendation 05.05 and the recommended value is -106 dBm. This is a general recommendation and therefore when preparing a link budget with certain manufacturer's equipment this vendor's recommendations can be used. MS sensitivity is also specified in the ETSI recommendation 05.05, where the receiver sensitivity value is separate for each MS class. For MS class 4, which means GSM 900, the recommended value is 102 dBm. Correspondingly for class 1, GSM 1800, the value is -100 dBm. The MS sensitivity can also be calculated using the information of receiver noise F and minimum Eb/No. The value for the noise is 10 dB and the minimum Eb/No is 8 dB, as defined in the ETSI recommendation 03.30. The receiver sensitivity Si is solved from the following equation, where the input noise power N is the product of three parameters: the Boltzman constant k, temperature To = 290 I K and bandwidth W = 271 kHz (54 dB): Ni=kToW (2.2) where = 8 