Reporting of system information (SI) hash values
Embodiments include methods for a user equipment (UE) operating in a wireless network. Such methods include, while operating in a non-connected state in the wireless network, obtaining system information (SI) broadcast in each of a plurality of cells visited by the UE and, for each of the visited cells, determining one or more SI hash values for the SI broadcast in the visited cell. Such methods also include sending, to a network node in the wireless network, at least a portion of the determined SI hash values as mobility history information (MHI). Other embodiments include complementary methods for a network node, as well as UEs and network nodes configured to perform such methods.
1 . A method for a user equipment (UE) configured to operate in a wireless network, the method comprising:
while operating in a non-connected state in the wireless network, obtaining system information (SI) broadcast in each of a plurality of cells visited by the UE;
for each of the visited cells, determining one or more SI hash values for the SI broadcast in the visited cell; and
sending, to a network node in the wireless network, at least a portion of the determined SI hash values as mobility history information (MHI), wherein one of the following applies:
the MHI includes, for each of the visited cell, a single SI hash value for all SI broadcast in the visited cell; or
the MHI includes, for each of the visited cell, a plurality of SI hash values that are associated with respective non-overlapping subsets of the SI broadcast in the visited cell.
2 . The method of claim 1 , wherein the MHI also includes, for each of the visited cell:
an identifier of the visited cell; and
a duration of time spent by the UE in the visited cell.
3 . The method of claim 1 , wherein the MHI also includes an indication of a hash algorithm used by the UE to determine the one or more SI hash values for each of the visited cell.
4 . The method of claim 1 , further comprising receiving, from the network node, a first indication of whether the UE should report available SI hash values, wherein the MHI is sent to the network node in response to the first indication indicating that the UE should report the available SI hash values.
5 . The method of claim 4 , wherein one of the following applies:
the first indication is received as broadcast SI; or
the method further comprises sending, to the network node, a second indication that the SI hash values are available to be reported as MHI, wherein the first indication is received as a request for UE information responsive to the second indication.
6 . The method of claim 4 , wherein when the first indication indicates that the UE should report the available SI hash values, the first indication is received together with further indications of one of the following:
a maximum number of the available SI hash values to report;
a maximum total size of the available SI hash values to report;
one or more subsets of broadcast SI for which the UE should report the available SI hash values; and
a hash algorithm to be used for determining the available SI hash values to be reported.
7 . The method of claim 6 , wherein determining the one or more SI hash values further comprises:
storing the obtained SI; and
after receiving the further indication of the hash algorithm, determining the one or more SI hash values based on the indicated hash algorithm.
8 . The method of claim 1 , further comprising selecting a signaling radio bearer (SRB) for sending the at least a portion of the determined SI hash values to the network node, based on a total size of the SI hash values being sent.
9 . A method for a network node configured to operate in a wireless network, the method comprising:
receiving, from a user equipment (UE) as mobility history information (MHI), one or more system information (SI) hash values for SI broadcast in one or more cells visited by the UE while the UE was operating in a non-connected state in the wireless network, wherein one of the following applies:
the MHI includes, for each of the one or more visited cells, a single SI hash value for all SI broadcast in the visited cell; or
the MHI includes, for each of the visited cell, a plurality of SI hash values that are associated with respective non-overlapping subsets of the SI broadcast in the visited cell.
10 . The method of claim 9 , wherein the MHI also includes, for each of the visited cell:
an identifier of the visited cell; and
a duration of time spent by the UE in the visited cell.
11 . The method of claim 9 , further comprising transmitting a first indication of whether the UE should report available SI hash values, wherein the MHI is received from the UE in response to the first indication indicating that the UE should report the available SI hash values.
12 . The method of claim 9 , further comprising:
obtaining, from one or more network nodes serving the one or more cells, SI hash values corresponding to the SI hash values received from the UE;
comparing the SI hash values received from the UE to the respective corresponding SI hash values; and
when an SI hash value does not match a corresponding SI hash value, detecting a network security problem associated with a network node that broadcasts the SI associated with the non-matching SI hash values.
13 . A user equipment (UE) configured to operate in a wireless network, the UE comprising:
radio transceiver circuitry configured to communicate with the wireless network via a plurality of cells; and
processing circuitry operatively coupled to the radio transceiver circuitry, whereby the processing circuitry and the radio transceiver circuitry are configured to:
while operating in a non-connected state in the wireless network, obtain system information (SI) broadcast in each of a plurality of cells visited by the UE;
for each of the visited cells, determine one or more SI hash values for the SI broadcast in the visited cell; and
send, to a network node in the wireless network, at least a portion of the determined SI hash values as mobility history information (MHI), wherein one of the following applies:
the MHI includes, for each of the visited cell, a single SI hash value for all SI broadcast in the visited cell; or
the MHI includes, for each of the visited cell, a plurality of SI hash values that are associated with respective non-overlapping subsets of the SI broadcast in the visited cell.
14 . The UE of claim 13 , wherein the MHI also includes, for each of the visited cell:
an identifier of the visited cell; and
a duration of time spent by the UE in the visited cell.
15 . The UE of claim 13 , wherein the MHI also includes an indication of a hash algorithm used by the UE to determine the one or more SI hash values for each of the visited cell.
16 . The method of claim 13 , wherein the processing circuitry and the radio transceiver circuitry are further configured to receive, from the network node, a first indication that the UE should report available SI hash values, wherein:
the MHI is sent to the network node in response to the first indication; and
one of the following applies:
the first indication is received as broadcast SI; or
the processing circuitry and the radio transceiver circuitry are further configured to send, to the network node, a second indication that the SI hash values are available to be reported as MHI, wherein the first indication is received as a request for UE information responsive to the second indication.
17 . A network node configured to operate in a wireless network, the network node comprising:
a communication interface configured to communicate with user equipment (UEs) and with one or more further nodes in the wireless network; and
processing circuitry operatively coupled to the communication interface, whereby the processing circuitry and the communication interface are configured to perform operations corresponding to the method of claim 9 .