Method and apparatus for acquisition of reliable time in a wireless network

A User Equipment (UE) configured for supporting acquisition of a corrected current time in a wireless network, comprising:

• a wireless transceiver configured to wirelessly communicate with base stations in the wireless network;
• at least one memory;
• at least one processor coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to:
• receive a public ciphering key for a base station from the wireless network;
• receive, via the wireless transceiver, a message broadcast from the base station, the message comprising:
• a digital signature for the base station, wherein the digital signature is based on a private ciphering key that corresponds to the public ciphering key, and
• a current time represented by a plurality of digits, wherein at least a portion of the plurality of digits representing the current time is ciphered;
• authenticate the current time in the message based on the digital signature for the base station, wherein authenticating the current time uses the public ciphering key;
• decipher at least the portion of the plurality of digits representing the current time that is ciphered;
• determine a propagation delay between the base station and the UE;
• and
• determine the corrected current time at the UE based on the current time, including at least the portion of the plurality of digits representing the current time that is deciphered, and the propagation delay.

A method performed by a base station for supporting acquisition of a corrected current time by a User Equipment (UE) in a wireless network, comprising:

• obtaining a current time;
• representing the current time using a plurality of digits;
• ciphering at least a portion of the plurality of digits representing the current time;
• sending a public ciphering key for the base station to the UE;
• and
• broadcasting a message comprising the current time and a digital signature for the base station, wherein the digital signature is based on a private ciphering key that corresponds to the public ciphering key;
• wherein the UE receives the message, obtains an unciphered current time by deciphering the ciphered portion of the current time, and determines a propagation delay between the base station and the UE, wherein the UE determines the corrected current time based on the unciphered current time and the propagation delay, wherein the UE authenticates the current time using the public ciphering key.

A base station configured for supporting acquisition of a corrected current time by a User Equipment (UE) in a wireless network, comprising:

• an external interface configured to wirelessly communicate with entities in the wireless network;
• at least one memory;
• at least one processor coupled to the external interface and the at least one memory, wherein the at least one processor is configured to:
• obtain a current time;
• represent the current time using a plurality of digits;
• cipher at least a portion of the plurality of digits representing the current time;
• and
• sending a public ciphering key for the base station to the UE;
• broadcast a message comprising the current time and a digital signature for the base station, wherein the digital signature is based on a private ciphering key that corresponds to the public ciphering key;
• wherein the UE receives the message, obtains an unciphered current time by deciphering the ciphered portion of the current time, and determines a propagation delay between the base station and the UE, wherein the UE determines the corrected current time based on the unciphered current time and the propagation delay, wherein the UE authenticates the current time using the public ciphering key.