Satellite operation of narrowband internet of things radio protocol
The present teachings disclose implementations of a UE and a method for providing a Narrowband Internet of Things (NB-IoT) network, the method including: receiving an NB-IoT downlink over a forward link; obtaining MAC configuration parameters, a transmit-timing offset and a transmit-frequency offset; pre-adjusting, to align with a return link timing and a return link frequency, a transmit-timing with the transmit-timing offset and a transmit-frequency with the transmit-frequency offset; requesting, based on the MAC configuration parameters and after the pre-adjusting, a connection with a Random-Access Preamble (RAR) over an NB-IoT uplink via the return link; and establishing the connection upon receiving a Random-Access Response (RAR), where a Round Trip-Time (RTT) from a transmitting antenna to a receiving antenna is greater than 67 microseconds (us), and both the NB-IoT downlink and the NB-IoT uplink use a mostly unchanged NB-IoT standard waveform. The NB-IoT service may be relayed by a satellite, for example, a geosynchronous earth orbit satellite. Further corrections to the timing and frequency may be performed on the connection. A cell or beam selection may be based on an NB-IoT system type, including NB-IoT over satellite, indicated in a Master Information Block.
1. A method for providing a Narrowband Internet of Things (NB-IoT) network, the method comprising:
receiving an NB-IoT downlink over a forward link;
obtaining MAC configuration parameters, a transmit-timing offset and a transmit-frequency offset;
pre-adjusting, to align with a return link timing and a return link frequency, a transmit-timing with the transmit-timing offset and a transmit-frequency with the transmit-frequency offset;
requesting a connection, based on the MAC configuration parameters and after the pre-adjusting, with a Random-Access Preamble (RAP) over an NB-IoT uplink via the return link; and
establishing the connection upon receiving a random-access response (RAR),
wherein a Round Trip-Time (RTT) from a transmitting antenna to a receiving antenna is greater than 67 microseconds (us), and
both the NB-IoT downlink and the NB-IoT uplink use a mostly unchanged NB-IoT standard waveform.
2. The method of claim 1 , wherein the RAR comprises a further timing correction and a further frequency correction, and the establishing comprises adjusting the transmit-timing with the further timing correction and the transmit-frequency with the further frequency correction.
3. The method of claim 1 , further comprising adjusting the transmit-timing with a further timing correction upon receiving a timing advance command.
4. The method of claim 1 , further comprising adjusting the transmit-frequency with a further frequency correction upon receiving a frequency correction command.
5. The method of claim 1 , wherein the obtaining comprises calculating the transmit-timing offset and the transmit-frequency offset based on a User Equipment location and ephemeris of a satellite or a High-Altitude Platform.
6. The method of claim 1 , wherein the obtaining comprises calculating the transmit-frequency offset based on a frequency Doppler shift.
7. The method of claim 1 , wherein the NB-IoT downlink comprises the transmit-timing offset and the transmit-frequency offset.
8. The method of claim 1 , wherein the RTT is greater than 1 millisecond (ms).
9. The method of claim 1 , wherein the forward link and the return link are relayed by a satellite or a High-Altitude Platform.
10. The method of claim 1 , further comprising updating random-access timers associated with the RAP based on the RTT.
11. The method of claim 1 , further comprising updating random-access timers associated with the RAP based on the RTT,
wherein the RAR comprises a further timing correction and a further frequency correction,
the establishing comprises adjusting the transmit-timing with the further timing correction and the transmit-frequency with the further frequency correction,
the RTT is greater than 1 millisecond (ms),
the forward link and the return link are relayed by a satellite or a High-Altitude Platform, and
the MAC configuration parameters comprise one or more of a random-access response window size, a MAC contention resolution timer, a system type, the transmit-timing offset, or the transmit-frequency offset.
12. The method of claim 1 , further comprising disabling a MAC HARQ protocol for the connection.
13. A User Equipment (UE) to communicate via a Narrowband Internet of Things (NB-IoT) network, the UE comprising:
a UE forward receiver module to receive an NB-IoT downlink over a forward link;
a UE synchronization module
to obtain MAC configuration parameters, a transmit-timing offset and a transmit-frequency offset, and
to pre-adjust, to align with a return link timing and a return link frequency, a transmit-timing with the transmit-timing offset and a transmit-frequency with the transmit-frequency offset; and
a UE connection module
to request, based on the MAC configuration parameters and after the pre-adjusting, a connection with a Random-Access Preamble (RAP) over an NB-IoT uplink via the return link, and
to establish the connection upon receiving a random-access response (RAR),
wherein a Round Trip-Time (RTT) from a transmitting antenna to a receiving antenna is greater than 67 microseconds (us),
the forward link and the return link are relayed by a satellite or a High-Altitude Platform, and
both the NB-IoT downlink and the NB-IoT uplink use a mostly unchanged NB-IoT standard waveform.
14. The UE of claim 13 , wherein the RAR comprises a further timing correction and a further frequency correction, and the UE connection module further adjusts the transmit-timing with the further timing correction and the transmit-frequency with the further frequency correction.
15. The UE of claim 13 , wherein the UE connection module is configured to adjust the transmit-timing with a further timing correction upon receiving a timing advance command.
16. The UE of claim 13 , wherein the UE connection module is configured to adjust the transmit-frequency with a further frequency correction upon receiving a frequency correction command.
17. The UE of claim 13 , wherein the UE connection module is configured to calculate the transmit-timing offset and the transmit-frequency offset based on a User Equipment location and ephemeris of the satellite or the High-Altitude Platform.
18. The UE of claim 13 , wherein the NB-IoT downlink comprises the transmit-timing offset and the transmit-frequency offset.
19. The UE of claim 13 , wherein the forward link and the return link are relayed by a satellite or a High-Altitude Platform.
20. The UE of claim 13 , wherein the UE connection module is configured to update random-access timers associated with the RAP based on the RTT,
the RAR comprises a further timing correction and a further frequency correction,
the UE connection module is configured to adjust the transmit-timing with the further timing correction and the transmit-frequency with the further frequency correction,
the RTT is greater than 1 millisecond (ms),
the forward link and the return link are relayed by a satellite or a High-Altitude Platform, and
the MAC configuration parameters comprise one or more of a random-access response window size, a MAC contention resolution timer, a system type, the transmit-timing offset, or the transmit-frequency offset.