n demodulating the reverse channel. It is useful with small numbers of signals, as seen in TD-SCDMA. The effect of JD is similar to thogonal codes, but the effect is partial rather than total. We will let V be the same- sector interference factor. In the case of normal CDMA demodulation, where we treat the interferers as AWGN and multiply by the channel PN code, we have V = 1. In the case of orthogonal codes, which we use in the forward direction, we have v=0. The effect of JD is somewhere in between the two. The effect of JD is to attenuate the same-sector interference, 28.4.4 Multipath Multipath in the reverse direction has a small effect on CDMA capacity because each reverse CDMA channel is using a different radio path to the base station. As we said in Sec. 28.3.4, the rake filter generates time sidelobes, an extra component of interference Y for each CDMA channel sharing the radio path. The effect of reverse multipath is to add Y interference, but only once for the signal channel time sidelobes. Thus Mbb = a + 1 - Ob Y. The combination of JD and mul- tipath gives us Mbb The effect of multipath in the reverse direc- tion is to add Y rather than to multiply by Y as we did in the forward direction. 28.5 Applying the Equations Statistically The CDMA equations represent a snapshot, a specific collection of users at a specific mo- ment in time with specific radio paths to all the base stations. These equations give significant insights into the capacity effects of various components of CDMA engineering. By themselves, the CDMA equations do not tell us how to do traffic engineering in a wireless telephone system. We need to take them one step further and try to use them on a distribution of CDMA traffic. 10 We can extend the CDMA equations to a distribu- tion of demand by replacing the sums with integrals in Eqs. (28.28) and (28.29): (x, dx dy (28.28) (28.29) 10 One of us (Rosenberg) built a sophisticated mathematical model for CDMA WLL using these equations in a statistical form. The view presented here is simpler