Network handover method and terminal device

1. A network handover method, comprising:

obtaining, by a terminal device, a link quality parameter of a data link of the terminal device, wherein the terminal device currently accesses a fifth generation communication (5G) system;

determining, by the terminal device, that the 5G system is unavailable in response to the link quality parameter meeting a specified condition; and

performing, by the terminal device, handing over from the 5G system to a non-5G system in response to determining that the 5G system is unavailable;

wherein the link quality parameter comprises a quantity of uplink data packets and a quantity of downlink data packets that are received in a specified duration; and

wherein the specified condition comprises at least one of a network card of the terminal device being in a first single passthrough state where the quantity of downlink data packets received in the specified duration by the terminal device exceeds a first threshold and a quantity of sent uplink data packets is o, or the network card of the terminal device being in a second single passthrough state where a quantity of uplink data packets sent by the terminal device in the specified duration, exceeds a second threshold and the quantity of received downlink data packets is o.

2. The method according to claim 1 , wherein the determining that the 5G system is unavailable comprises:

sending a test data packet to a specified public network server in response to the link quality parameter meeting the specified condition; and

determining that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

3. The method according to claim 1 , wherein the determining that the 5G system is unavailable comprises:

parsing a historical domain name in a buffer in response to the link quality parameter meeting the specified condition;

determining that the 5G system is unavailable in response to the parsing failing;

sending a test data packet to a specified public network server in response to parsing succeeding; and

determining that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

4. The method according to claim 1 , further comprising performing, after determining that the 5G system is unavailable:

sequentially recovering a network using four stages of reestablishment policies comprising querying a route, reconfiguring the route, re-registration, and enabling/disabling an airplane mode; and

wherein the handing over from the 5G system to a non-5G system comprises handing over to the non-5G system in response to the sequentially recovering the network being unsuccessful.

5. The method according to claim 1 , further comprising performing after determining that the 5G system is unavailable:

recovering a network by querying a route; and

wherein the handing over from the 5G system to a non-5G system comprises:

handing over to the non-5G system in response to the recovering the network being unsuccessful.

6. The method according to claim 1 , wherein the 5G system is non-standalone networking (NSA), and the terminal device accesses a heterogeneous communication system comprising the 5G system and a long term evolution (LTE) system; and

wherein the handing over from the 5G system to the non-5G system comprises:

triggering a network device to indicate the terminal device to hand over to the LTE system by sending, to the network device, when the terminal device is in a connected state, capability information that the terminal device does not support the 5G system; and

suppressing reporting of a measurement result of the 5G system when the terminal device is in an idle state, and skipping enabling a random access function of the 5G system, wherein the suppressing the reporting of the measurement result and the skipping enabling the random access function causes the terminal device to access the LTE system in an autonomous network search manner.

7. The method according to claim 1 , wherein the 5G system is standalone networking (SA); and

wherein the handing over from the 5G system to the non-5G system comprises:

triggering, by sending, to a network device, capability information that the terminal device does not support the 5G system, the network device to indicate the terminal device to hand over to the non-5G system.

8. A terminal device, comprising:

a processor; and

a non-transitory computer readable memory storing one or more computer programs for execution by the processor, the one or more computer programs including instructions to:

obtain a link quality parameter of a data link of the terminal device, wherein the terminal device currently accesses a fifth generation communications (5G) system;

determine that the 5G system is unavailable in response to the link quality parameter meeting a specified condition; and

hand over from the 5G system to a non-5G system in response to determining that the 5G system is unavailable;

wherein the link quality parameter comprises a quantity of uplink data packets and a quantity of downlink data packets that are received in a specified duration, and wherein the specified condition comprises a network card of the terminal device being in a first single passthrough state where the quantity of downlink data packets received in the specified duration by the terminal device exceeds a first threshold and a quantity of sent uplink data packets is 0, or the specified condition comprises the network card of the terminal device being in a second single passthrough state where a quantity of uplink data packets sent in the specified duration by the terminal device exceeds a second threshold and the quantity of received downlink data packets is 0.

9. The terminal device according to claim 8 , wherein the program further includes instructions to:

send a test data packet to a specified public network server in response to the link quality parameter meeting the specified condition; and

determine that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

10. The terminal device according to claim 8 , wherein the program further includes instructions to:

parse a historical domain name in a buffer in response to the link quality parameter meeting the specified condition;

determine that the 5G system is unavailable in response to the parsing failing;

send a test data packet to a specified public network server in response to the parsing succeeding; and

determine that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

11. The terminal device according to claim 8 , wherein the program further includes instructions to:

sequentially recover a network using four stages of reestablishment policies comprising querying a route, reconfiguring the route, re-registration, and enabling/disabling an airplane mode; and

hand over to the non-5G system in response to the sequentially recovering the network being unsuccessful.

12. The terminal device according to claim 8 , wherein the program further includes instructions to:

recover a network by querying a route; and

hand over to the non-5G system in response to the recovering the network being unsuccessful.

13. The terminal device according to claim 8 , wherein the 5G system is non-standalone networking (NSA), and the terminal device accesses a heterogeneous communication system comprising the 5G system and a long term evolution (LTE) system; and

wherein the program further includes instructions to:

triggering a network device to indicate the terminal device to hand over to the LTE system by sending, to the network device, when the terminal device is in a connected state, capability information that the terminal device does not support the 5G system; and

suppressing reporting of a measurement result of the 5G system when the terminal device is in an idle state, and skipping enabling a random access function of the 5G system, wherein the suppressing the reporting of the measurement result and the skipping enabling the random access function causes the terminal device to access the LTE system in an autonomous network search manner.

14. The terminal device according to claim 8 , wherein the 5G system is standalone networking (SA); and

wherein the program further includes instructions to:

trigger a network device to indicate the terminal device to hand over to the non-5G system by sending, to the network device, capability information that the terminal device does not support the 5G system.

15. A chip, wherein the chip is coupled to a memory and is configured to execute a computer program stored in the memory, to perform:

obtaining a link quality parameter of a data link of a terminal device associated with the chip, wherein the terminal device currently accesses a fifth generation communication (5G) system;

determining that the 5G system is unavailable in response to the link quality parameter meeting a specified condition; and

handing over from the 5G system to a non-5G system in response to determining that the 5G system is unavailable;

wherein the link quality parameter comprises a quantity of uplink data packets and a quantity of downlink data packets that are received in a specified duration; and

wherein the specified condition comprises at least one of a network card of the terminal device being in a first single passthrough state where the quantity of downlink data packets received in the specified duration by the terminal device exceeds a first threshold and a quantity of sent uplink data packets is 0, or the network card of the terminal device being in a second single passthrough state where a quantity of uplink data packets sent by the terminal device in the specified duration, exceeds a second threshold and the quantity of received downlink data packets is 0.

16. The chip according to claim 15 , wherein the determining that the 5G system is unavailable comprises:

sending a test data packet to a specified public network server in response to the link quality parameter meeting the specified condition; and

determining that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

17. The chip according to claim 15 , wherein the determining that the 5G system is unavailable comprises:

parsing a historical domain name in a buffer in response to the link quality parameter meeting the specified condition;

determining that the 5G system is unavailable in response to the parsing failing;

sending a test data packet to a specified public network server in response to parsing succeeding; and

determining that the 5G system is unavailable in response to a probe result of the test data packet indicating that the data link is disconnected.

18. The chip according to claim 15 , further comprising performing, after determining that the 5G system is unavailable:

sequentially recovering a network using four stages of reestablishment policies comprising querying a route, reconfiguring the route, re-registration, and enabling/disabling an airplane mode; and

wherein the handing over from the 5G system to a non-5G system comprises handing over to the non-5G system in response to the sequentially recovering the network being unsuccessful.

19. The chip according to claim 15 , further comprising performing, after determining that the 5G system is unavailable:

recovering a network by querying a route; and

wherein the handing over from the 5G system to a non-5G system comprises:

handing over to the non-5G system in response to the recovering the network being unsuccessful.

20. The chip according to claim 15 , wherein the 5G system is non-standalone networking (NSA), and the terminal device accesses a heterogeneous communication system comprising the 5G system and a long term evolution (LTE) system; and

wherein the handing over from the 5G system to the non-5G system comprises:

triggering a network device to indicate the terminal device to hand over to the LTE system by sending, to the network device, when the terminal device is in a connected state, capability information that the terminal device does not support the 5G system; and

suppressing reporting of a measurement result of the 5G system when the terminal device is in an idle state, and skipping enabling a random access function of the 5G system, wherein the suppressing the reporting of the measurement result and the skipping enabling the random access function causes the terminal device to access the LTE system in an autonomous network search manner.