Synchronization

To make this transmission method work it is not enough just to have a fancy coding scheme. To keep track of all this information flying back and forth we need to synchronize it with a master clock. As the CDG puts it, "In the final stages of the encoding of the radio link from the base station to the mobile, CDMA adds a special "pseudo-random code" to the signal that repeats itself after a finite amount of time. Base stations in the system distinguish themselves from each other by transmitting different portions of the code at a given time. In other words, the base stations transmit time offset versions of the same pseudo-random code."

Arrgh. Another phrase with the word 'code in it, one more term to keep track of! Don't despair. Even if "pseudo-random code" is fiercesomely titled, it's chore is simple to state: keep base station traffic to its own cell site by issuing a code. Synchronize that code with a master clock to correlate the code. Like putting a time stamp on each piece of information. CDMA uses The Global Positioning System or GPS, a network of navigation satellites that, along with supplying geographical coordinates, continuously transmits an incredibly accurate time signal.

Permalink

Post a comment (If you haven't left a comment here before, you may need to be approved by the site owner before your comment will appear. Until then, it won't appear on the entry. Thanks for waiting.)

Name:

Email Address:

URL:

Remember personal info?

Comments: (you may use HTML tags for style)

Human Verification:

Search the site | by Google:
Subscribe to Private Line's feed
[What is this?] Article Index I. Introduction II. Cellular History III. Cell Sector Terminology IV. Basic Theory and Operation IX. Code Division Multiple Access: IS-95 A. Before We Begin: A Cellular Radio Review B. Back to the CDMA Discussion C. Summary of CDMA D. A different way to share a channel E. F. What Every Radio System Must Consider G. CDMA Benefits H. Call Processing: A Few Details V. Cellular frequency and channel discussion VI. Channel Names and Functions VII. AMPS Call Processing A. Registration B. Pages: Getting a call C. The SAT, Dial Tone, and Blank and Burst D. Origination: Making a call E. Precall Validation VIII. AMPS and Digital Systems compared X. Appendix A. AMPS Call Processing Diagram B. Land Mobile or IMTS C. Early Bell System Overview of Amps D. Link to Professor R.C. Levine's article XI. Additional Assistance A. Q&A: Cell Tower Capacity Recent Posts What Every Radio System Must Consider CDMA Benefits Call Processing: A Few Details Appendix AMPS Call Processing Land Mobile or IMTS Early Bell System Overview of Amps Link to Professor R.C. Levine's article Cell Tower Lease Expert Q&A: Cell Tower Capacity Powered by
Movable Type 3.2 HomeNewsContentCellular Telephone BasicsDigital Wireless BasicsGSM HistoryTelecommunications HistoryTelephone HistorySwitching & TransmissionContact