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View Full Version : Can a HRPD terminal obtain a cell site SID without a session?



Charles314
2012-01-13, 03:19 PM
For HRPD systems (1xEV-DO 0, a, b, etc.), I am having difficulty understanding when an access terminal receives the SID of an access network. In 1xRTT, the SID is being constantly broadcast on the Sync channel with a Sync message. In HRPD, the Sync message is constantly broadcast on the Control Channel but the data fields are only 1) MessageID, 2) MaximumRevision, 3) MinimumRevision, 4) PilotPN and 5) SystemTime.

I see that the HRPD Location Updata procedure in the Application layer provides a way for the access terminal to request the SID of the access network but I assume that I must be missing something. Why would HRPD systems be designed to allow for obtaining the SID ONLY after a session has been established? If the access terminal's perferred roaming list has PREF_ONLY=1 and the access network of which the access terminal is attempting to connect has its SID set as PREF_NEG=0 then it has to go all the way through session establishment just to figure out that the base station it is attempting to access is not one that it is permitted to connect to. It seems so ineffecient, hence the reason why I believe I am confused.

Also, the QuickConfig message and the SectorParameters message of the Overhead Messages Protocol (broadcast on the Control Channel before a session is established) also contain no SID so this does not eliminate the need to establish a session in order for the access terminal to obtain the SID.

So, do the access networks broadcast their SIDs (prior to a session) in some way that I am missing or in some way that is not in the standards? Do HRPD access terminal manufactures configure the devices to have the capability to obtain the SID before establishing a session and before having to receive it with a unicast message after session establishment?

I appreciate any help and references to applicable standards. If I am not confused, then what is the point of waiting until a session is established before the access network reveals its SID? I don't see any reason why anyone would want to change from how it was done in 1xRTT.