why does the reverse link of an IS95 DSCDMA system not emplo

why does the reverse link of an IS-95 DS-CDMA system not employ coherent demodulation?

Solution

IS-95 DS-CDMA system not employ coherent demodulation due to the following reasons:

In IS-95 DS-CDMA, transmissions are asynchronous on the uplink, but synchronous on the downlink.

On the reverse link, every user uses the same set of short sequences for modulation. The length of these sequences is 2¹⁵

Each access channel and each traffic channel gets a different long PN sequence. The long sequences are used to separate the signals from different users on the reverse link (CDMA).