To illustrate a basic case, we use the link reference parameter, i.e. Eb/No, or energy per pit per noise power density, which later will apply to the link budget frame work. Picking it up from equation (2.6), we consider the generic reverse-link capacity in CDMA¹2 as the limiting factor. Thus, assuming perfect power control for this instance, the received powers from all mobiles users are the same. Then S-M-1 (7.1) N M - 1 where M is the total number of active users in a given band, and where the total inter- ference power in the band equals the sum of powers of single users. Now equating the energy per bit to the average modulating signal power we defined (7.2) where S is the average modulating signal power, T is bit time duration, and R is the bit rate, i.e. 1/T. Then, incorporating the noise power density No, which is the total noise power N divided by the bandwidth B (i.e. No = N/B), we get (7.3) Solving for M yields and for large M we get (7.4) where Gp corresponds to the system processing gain defined in equation (2.3), and M defines the number of projected users in a single CDMA cell with omnidirectional an- tenna without interference from neighbouring cells users transmitting continuously. 7.6.5.2 The Cell Loading Effect Since in real 3G mobile networks there always exists more than one cell and more than one sector, we need to introduce a loading effect due to interference from neighbouring cells as follows: 12 Mainly in rural areas; in urban area the downlink may/will become the limiting factor. The UMTS Network and Radio Access Technology (7.5) where is the loading factor (ranging from 0 to 100%) as introduced in equation (2.29). Typical values will range from 45 to 50%. The inverse of as (1 + (3) has often been defined as the frequency re-use factor, i.e. F = 1/(1 + 3). The ideal single cell CDMA value of F = 1 (i.e. = 0) decreases as the loading of multi-cell environments increase. Sectorization can decrease interference from other users in other cells. Thus, instead of deploying only omnidirectional