Successfully acquiring the Time of Day is not mandatory for a successful registration, but is necessary for ongoing operation. The specific timeout for Time of Day Requests is implementation dependent. However, the SS shall not exceed more than 3 Time of Day requests in any 5 min period.

6.2.9.12 Transfer operational parameters

After DHCP is successful, the SS shall download the SS Configuration File (9.2) using TFTP on the SS’s Secondary Management Connection, as shown in Figure 52. The TFTP Configuration File server is specified by the “siaddr” field of the DHCP response. The SS shall use an adaptive timeout for TFTP based on binary exponential backoff [IETF RFC 1123, IETF RFC 2349].

The parameter fields required in the DHCP response and the format and content of the configuration file shall be as defined in 9.2. Note that these fields are the minimum required for interoperability.

6.2.9.13 Establish provisioned connections

After the transfer of operational parameters, the BS shall send DSA-REQ messages to the BS to set up connections for preprovisioned service flows belonging to the SS. The SS responds with DSA-RSP messages. This is described further in 6.2.13.7.1.

6.2.10 Ranging

The BS shall provide each SS a periodic Ranging opportunity at an interval sufficiently shorter than T4 that a map could be missed without the SS timing out. The size of this “subinterval” is BS dependent. For GPSS mode subscriber stations, any allocation of uplink bandwidth constitutes a Ranging opportunity.

The SS shall reinitialize its MAC sublayer after T4 seconds have elapsed without receiving a Periodic Ranging opportunity. The SS shall also reinitialize its MAC sublayer if it receives a RNG-RSP message from the BS with the Ranging Status field set to 4 (rerange). In both cases, the SS shall also re-register.

Remote RF signal level adjustment at the SS is performed through a station maintenance function using the RNG-REQ and RNG-RSP MAC messages. This is similar to initial ranging and is shown in Figure 55 and Figure 56.

6.2.10.1 Downlink burst profile management in framed operation

The downlink burst profile is determined by the BS according to the quality of the signal that is received by each SS. To reduce the volume of uplink traffic, the SS monitors the carrier to noise and interference ratio [C/(N+I)] and compares the average value against the allowed range of operation. This region is bounded by threshold levels. If the received C/(N+I) goes outside of the allowed operating region, the SS requests a change to a new burst profile using one of three methods. If the SS has a station maintenance interval available, it shall send a RNG-REQ message to which the BS responds with a RNG-RSP message. Otherwise, the SS shall send a DBPC-REQ message in an uplink allocation addressed to that SS’s basic connection (regardless of whether the SS is GPC or GPT). The BS responds with a DBPC-RSP message. If neither of these options is available and the SS requires a more robust burst profile on the downlink, the SS shall send a RNG-REQ message in an Initial Maintenance interval. In all three methods, the message is sent using the Basic CID of the SS. The coordination of message transmit and receipt relative to actual change of modulation is different depending upon whether an SS is transitioning to a more or less robust burst profile. Figure 57 shows the case where an SS is transitioning to a more robust type. Figure 58 shows transition to a less robust burst profile.

The SS applies an algorithm to determine its optimal burst profile in accordance with the threshold parameters established in the DCD message in accordance with Figure 59.

Done

NOTES:

1—Means ranging is within the tolerable limits of the BS.

2—RNG-REQ pending-until-complete was nonzero, the BS should hold off the station maintenance opportunity accordingly unless needed, for example, to adjust the SS’s power level.

Figure 55—Periodic Ranging—BS

Figure 57—Transition to a more robust burst profile

Figure 58—Transition to a less robust burst profile