Two ways to get more data through

On a channel whose bandwidth is fixed by physics, there are two ways to move more information: send symbols faster, or spend fewer bits on the same information. The second costs less to implement and holds up better in the hole.

What can be compressed

• Differential transmission — Inclination, azimuth and toolface change little from one reading to the next, so sending the increment costs less bandwidth than sending the absolute value.
• Adaptive resolution — Sliding calls for a fast toolface update; rotating puts the emphasis on gamma and inclination. Allocating bandwidth by drilling state is more efficient than a fixed frame format.
• Downlink on demand — Surface can downlink a command to switch the measurement sequence, so not every channel has to transmit continuously.

More useful figures than peak rate

On the job, two numbers matter more than peak rate: how long one complete survey takes from measurement to the driller’s display, and the toolface update interval while sliding. Both convert directly into rig time.