A DS-CDMA cellular mobile system uses QPSK modulation having raised-cosine shaped filtering with roll-off factor of 0.22. Its base stations are equipped with 3-sector antennas. The user data rate is 32 Kb/s, spreading factor is 128, voice activity factor is 1, and inter-cell-to-intra-cell interference power ratio is 1/2. If a desired bit error rate per user of 10-3 is required, calculate how many users one cell can serve. Assume that the effect of thermal noise on the number of users is negligible.
（DS-CDMA蜂窝移动系统使用QPSK调制，QPSK调制具有滚降因子为0.22的升余弦形滤波。它的基站配备了3扇区天线。用户数据速率为32kb/s，扩展因子为128，话音活动因子为1，小区间干扰功率比为1/2。如果要求每个用户的期望误码率为10-3，则计算一个小区可以服务多少用户。假设热噪声对用户数量的影响可以忽略不计。）
这个题想用下图的公式计算，请问Eb/Io怎么算啊，还有Bt总带宽算出来是19.52kHz。fb比特率算出来是32kbit/s。不知道对不对，求大佬。
