Monday, January 3, 2011

Messages in CDMA

 I want to speak about messages in CDMA , how it sent and what the call processing

**  In CDMA, most call processing events are driven by messages.
** Some CDMA channels exist for the sole purpose of carrying, they never carry user’s voice traffic.
          • Sync Channel (a forward channel).
          • Paging Channel (a forward channel).
          • Access Channel (a reverse channel).
          • On these channels, there are only messages, continuously all of the time.
** Some CDMA channels exist just to carry user traffic.
          • Forward Traffic Channel.
          • Reverse Traffic Channel.
          • On these channels, most of the time is filled with traffic and messages are sent only when there is something to do.
** All CDMA messages have very similar structure, regardless of the channel on which they are sent.


Now , How CDMA Messages are Sent ?
** CDMA messages on both forward and reverse traffic channels are normally sent via  dim-and-burst.
** Messages include many fields of binary data.
** The first byte of each message identifies message type: this allows the recipient to parse the contents.
** To ensure no messages are missed, all CDMA messages bear serial numbers and important messages contain a bit requesting acknowledgment.
** Messages not promptly acknowledged are retransmitted several times. If not acknowledged,
the sender may release the call.
** Field data processing tools capture and display the messages for study.

1 comments :

Jimmy said...

Amazing article! :) Thanks for the clarification, was wondering for some time, but never found the time to check.

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Cheap Calls Australia

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