ACC_MSG_SEQ
CHAN_LST_MSG_SEQ
CONFIG_MSG_SEQ
NGHBR_LST_MSG_SEQ
SYS_PAR_MSG_SEQ
Definition: The message sequence numbers are defined as below:
ACC_MSG_SEQ is the Access Message Sequence Number
CHAN_LST_MSG_SEQ is the Channel List Message Sequence Number
CONFIG_MSG_SEQ is the Configuration Message Sequence Number NGHBR_LST_MSG_SEQ is the Neighbor List Message Sequence Number
SYS_PAR_MSG_SEQ is the System Parameters Message Sequence Number
IS-95 establishes the system configuration using three types of configuration messages. The configuration messages are the System Parameters Message, the Neighbor List Message, and the CDMA Channel List Message. Each particular configuration message contains a Configuration Message Sequence Number, denoted by CONFIG_MSG_SEQ. When the contents of any one of the three configuration messages changes, the value of CONFIG_MSG_SEQ transmitted with any of the three messages types is incremented by one. The System Parameters Message Sequence Number, SYS_PAR_MSG_SEQ, is the CONFIG_MSG_SEQ number transmitted with the System Parameters Message. Also the Neighbor List Message Sequence Number, NGHBR_LST_MSG_SEQ, is the CONFIG_MSG_SEQ number transmitted with the Neighbor List Message. Likewise, the Channel List Message Sequence Number, CHAN_LST_MSG_SEQ, equals the Configuration Message Sequence Number transmitted with the Channel List Message. These numbers are used by the system to allow the mobile station to know when it has a current set of configuration parameters.
As the mobile receives its configuration messages, it records the four Message Sequence Numbers NGHBR_LST_MSG_SEQ, SYS_PAR_MSG_SEQ, and CHAN_LST_MSG_SEQ, and the most recent CONFIG_MSG_SEQ. The mobile station considers its recorded set of configuration parameters to be current only if all the following conditions are met:
- All three stored configuration message sequence numbers (NGHBR_LST_MSG_SEQ, SYS_PAR_MSG_SEQ, and CHAN_LST_MSG_SEQ) are equal to the value of the most recent CONFIG_MSG_SEQ; and
- CONFIG_MSG_SEQ in not set to NULL, which is not an allowed sequence number and tells the mobile it needs to receive a bonafide set of con- figuration messages; and
- No more than 10 minutes have elapsed since the mobile station last received a valid message on the Paging Channel which sent the stored configuration parameter values.
If the CONFIG_MSG_SEQ number of the received message matches the value for that message type stored in the mobile station, then the mobile station may ignore that message. In the standard, the received Configuration Message Sequence Number is often subscripted with an "r" and the stored message sequence number is subscripted with an "s". For example, if the received CONFIG_MSG_SEQ number, denoted by CONFIG_MSG_SEQr, does not equal the currently stored System Parameters Message Sequence Number, denoted by SYS_PAR_MSG_SEQs, then the values of that System Parameters Message are demodulated and stored. In addition, CONFIG_MSG_SEQs and SYS_PAR_MSG_SEQs are both updated by being set equal to CONFIG_MSG_SEQr.
A similar procedure is used for the Access Parameters Message using an Access Message Sequence Number ACC_MSG_SEQ. When an Access Parame-ters Message is received, the received sequence number ACC_MSG_SEQr is compared to the currently stored Access Parameters Message sequence number, ACC_MSG_SEQs. If the comparison is a match, the mobile station ignores that Access Parameters Message. If the comparison is not a match, the mobiles sets its stored ACC_MSG_SEQs to the received ACC_MSG_SEQr number and demodulates the Access Parameters Message and stores and uses its values when it next accesses the system.
ACC_MSG_SEQ
CHAN_LST_MSG_SEQ
CONFIG_MSG_SEQ
NGHBR_LST_MSG_SEQ
SYS_PAR_MSG_SEQ
Example: The CONFIG_MSG_SEQ number (and hence all other configuration message sequence numbers) and the Access Message Sequence Number ACC_MSG_SEQ are 6 bit binary numbers (zero to 63 decimal). These values are incremented by one each time a message is updated.
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