Questions about the nRF160's LTE and GPS processing priorities

[Kenny]

Hello, All;

Using your nRF9160 chip to develop, there are some questions when using the network and positioning, Hope to get your answer:

1. Can LTE work at the same time as GPS ? If not, what is the order of precedence and processing logic between them ?

2. If the current LTE data transfer is in progress, is the GPS necessarily blocked?

3. Does GPS always have lower priority than LTE ? Is there any way to improve this problem?

Hope to get your reply soon, thank you !

[Kenny]

GPS will be blocked by LTE, how long will it be blocked, and how is it handled?

[Øyvind]

Hi Kenny,

1. Can LTE work at the same time as GPS ? If not, what is the order of precedence and processing logic between them ?

No, the LTE and GPS are time multiplexed. As described in the GPS Receiver chapter in the nRF9160 Product Specification:

The GPS receiver supports GPS L1 C/A and QZSS L1 C/A reception. Operation is time multiplexed with LTE modem, and it is possible to use the GPS and QZSS receiver to obtain position either while the LTE is in RRC Idle mode or power saving mode (PSM), or when the LTE modem is completely deactivated.

2. If the current LTE data transfer is in progress, is the GPS necessarily blocked?

Yes, see answer above.

3. Does GPS always have lower priority than LTE ? Is there any way to improve this problem?

This will be controlled by e.g. power saving mode (PSM). The PSM is negotiated with the LTE network, this means that you can send a desired value using the AT+CPSMS. The network will provide a value, however not always the wanted value. Whenever the device is in PSM mode, the GPS will be able to communicate with satellites. 

Kenny said:

GPS will be blocked by LTE, how long will it be blocked, and how is it handled?

See answer above. 

Our online power profiler for LTE might be a good source of information. Our nRF9160 Guidelines white paper - nWP041 - nRF9160 Modem Sleep Notifications has more information, also, please see the nWP044 - Best practices for cellular IoT development.

Kind regards,
Øyvind