Category: CDMA

All base stations digital transmissions are referenced to a common CDMA system-wide time scale that uses the GPS time scale, which is traceable to and synchronous with Universal Coordianted Time…

Once the data has been scrambled with the user specific long code, the closed loop power control data is then punctured into the data stream. Remember that the power control…

After all of the coding used so far in the forward channel, you’re probably wondering why the data needs to be scrambled again at the same rate. If all cells…

Auto-correlation is simply a comparison of a signal against itself. For a digital sequence, such as the short codes used in EIA/TIA-95-B, this comparison is a measure of the number…

Pilot Channel Physical Layer The Pilot channel is essentially the short codes operating on their assigned PN offset. This is accomplished by selecting Walsh code 0 which is 64 zeroes…

There are two key reasons that Walsh codes are not used for the channelization in the reverse link: Mobile transmission are not time aligned and therefore cannot be orthogonal, and…

Reverse Channel Long Code Spreading The channelization in the reverse link must provide for unique code assignments for every operational phone. Long Code Spreading  Provides Unique Mobile Channelization Mobiles are…

If the modulation data changes, QPSK modulation makes one symbol change each period. If the data is the same, then QPSK and OQPSK do not change state. However, if the…

A number of different service options have been defined for use on the CDMA physical channel. A description of each of the service options follows: Service Option 001 – This…

Sectorization gain can be somewhat of a misleading term. One could think of the  sectorization gain as more of a reduction factor. For an omni site, the sectorization gain is…