Abnormal current drain soon after MediaFLO activation in fringe coverage areas in MBP1600, MBP1610, MBP2600, MBP2700

Problem Statement:

OEMs may observe that devices show a larger-than-normal current consumption (~150mA) soon after MediaFLO activation. The source of the increased power consumption can point to the decoding of the config. flow for an extended duration. This issue had been previously reported in a fringe MediaFLO coverage area (RSSI range between -93dBm ~ -98dBm) only. There have been no instances of this issue happening in any other markets or in good coverage areas.

Affected Devices:

All FLOTV commercial devices on Verizon Wireless and AT&T in the U.S.

Explanation:

The config. flow carries resources such as service icons as well as mandatory files such as EULAs and device configuration files. These resources and files are typically pre-loaded on the device along with the MediaFLO Service Core software. The config flow decode can be triggered by two conditions:

- The first use case is when there is an update to the resources and files broadcast over the config flow. In this case, the Service core will detect a change in the config flow version and then go ahead and re-download the changed resources and files. Dynamic updates to the config flow are very infrequent and typically occur only when there is a service line up change on FLOTV.

- The second use case is when there are resources available over the air that are not pre-loaded and in this case the Service Core will schedule a one-time download of the missing resources immediately after successful activation.

Impact Analysis:

The behavior observed has meaningful impact only if all of the following conditions are met

- Device is activated for the first time and acquires initial system information but then roams into fringe coverage within the first few minutes
- Device stays resident in fringe coverage for an extended duration of time immediately after activation.
- User does not have the MediaFLO UI on the foreground in fringe coverage

Assuming a 1000mAHr battery rating and an average 50mAHr current drain, the device will need to stay stationary for atleast 20 hours before the battery is completely drained.

Summary and Recommendation:

The probability of occurence of this condition in real life is very small. Based on past experience with several commercial devices deployed in the U.S. over the past two years, this has not been a scenario that was ever encountered/reported in the field. Additionally, the config flow decode will terminate immediately upon roaming completely out of FLO coverage or moving back into FLO coverage and the pending resources are acquired. So the recovery mechanism is robust, well tested and very effective.

Addressing this one-time edge condition will involve a highly risky design and software change at both the FLO protocol stack and the Service Core layers, and the risks far outweigh the benefits.