Verifying generic broadcast of location assistance data

Patent metadata

Field	Value
Publication number	US-9271256-B2
Application number	US-201213598553-A
Country	US
Kind code	B2
Filing date	Aug 29, 2012
Priority date	Aug 30, 2011
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

Various techniques are provided for Location Services (LCS) Assistance Data broadcast, for example for implementation in LTE and LTE-A systems. The embodiments described herein may use the LPP/LPPe positioning protocol, by making use of existing unsolicited Provide Assistance Data (PAD) messages. Embodiments avoid the need to define and implement a separate broadcast Assistance Data protocol. Additional exemplary embodiments for scheduling and verifying of the broadcast Assistance Data messages are described herein.

First claim

What is claimed is:

1. A method for verifying a broadcast message, the method comprising:
receiving the broadcast message, at a device, from a Location Server wherein the broadcast message comprises Assistance Data (AD) for location services and a plurality of broadcast control parameters;
determining that the broadcast message is ciphered;
in response to determining that the broadcast message is ciphered, determining that the device has at least one key to decipher the ciphered broadcast message; and
deciphering the broadcast message using the at least one key and an initial counter, wherein deriving the initial counter comprises:
receiving a first value associated with the initial counter using point-to-point mode from the Location Server;
receiving a second value associated with the initial counter using broadcast mode from the Location Server; and
deriving the initial counter using at least the first value and the second value;
verifying a validity of the AD using at least one control parameter from the plurality of broadcast control parameters received from the Location Server.

2. The method of claim 1 , wherein the AD is ciphered using symmetric cryptography.

3. The method of claim 1 , wherein determining that the device has the at least one key to decipher the ciphered broadcast message comprises using a cipher Key ID contained in the at least one control parameter that indicates the at least one key that should be used in deciphering the broadcast message.

4. The method of claim 1 , wherein the broadcast message is encapsulated.

5. The method of claim 1 , wherein deciphering the AD from the broadcast message further comprises using a counter from the plurality of broadcast control parameters.

6. The method of claim 5 , wherein another counter for a subsequent broadcast message is derived using the counter from the current broadcast message.

7. The method of claim 1 , wherein the broadcast message is an LTE Positioning Protocol (LPP) message or an LPP/LPP Extensions (LPPe) Provide Assistance Data message.

8. The method of claim 1 , further comprising verifying a validity of the AD using at least one control parameter from the plurality of broadcast control parameters received from the Location Server.

9. The method of claim 8 , further comprising receiving information associated with broadcasting to the device from the Location Server, wherein the information associated with the broadcasting is received point to point using a positioning protocol, and wherein verifying the validity of the AD uses the information received point to point.

10. The method of claim 9 , wherein verifying the validity of the AD comprises:
determining that the device is configured to require digitally signed broadcast messages based on the information associated with the broadcasting received point to point;
determining that the broadcast message is not digitally signed; and
discarding the broadcast message, in response to determining that the broadcast message is not digitally signed.

11. The method of claim 8 , wherein verifying the validity of the AD comprises:
determining that the broadcast message is not a duplicate message by checking at least one parameter from the plurality of broadcast control parameters that indicates a uniqueness of the broadcast message for at least a predefined period of time.

12. The method of claim 8 , wherein verifying the validity of the AD comprises:
determining applicability of the broadcast message based on a time indicator from the plurality of broadcast control parameters, wherein the device uses the time indicator in determining if the validity of the AD has yet to occur or has already expired.

13. The method of claim 8 , wherein verifying the validity of the AD comprises:
determining applicability of the broadcast message based on a geographic area indicator from the plurality of broadcast control parameters, wherein the device uses the geographic area indicator in determining if the broadcast message is valid for the device based on a device's location.

14. The method of claim 8 , wherein verifying the validity of the AD comprises:
determining that the broadcast message comprises at least one type of AD that is needed by the device.

15. The method of claim 8 , wherein verifying the validity of the AD comprises:
determining that the broadcast message is digitally signed;
in response to determining that the broadcast message is digitally signed, determining that the device has at least one key to perform authentication verification for the digitally signed broadcast message; and
verifying the validity of the broadcast message by verifying a digital signature for the broadcast message using the at least one key.

16. The method of claim 15 , wherein the broadcast message is encapsulated.

17. The method of claim 15 , wherein the broadcast message is digitally signed using asymmetric cryptography.

18. The method of claim 15 , wherein the device begins the authentication verification for the digitally signed broadcast message before receiving the entire broadcast message by identifying the at least one key by using a public key identifier from the digital signature that appears at the beginning of the broadcast message.

19. The method of claim 15 , wherein verifying the digital signature comprises:
converting the digital signature for the broadcast message using the at least one key; and
comparing a representation of the broadcast message against the converted digital signature; and
determining that the broadcast message is authentic if the converted digital signature is the same as the representation of the broadcast message.

20. The method of claim 19 , wherein the representation of the broadcast message is a Secure Hash Algorithm (SHA) based hash.

21. The method of claim 8 , further comprising:
at least temporarily ceasing use of a broadcast system associated with the broadcast message if a plurality of broadcast messages fail during the verification for the broadcast message.

22. A device, comprising:
a transceiver configured to:
receive a broadcast message from a Location Server wherein the broadcast message comprises Assistance Data (AD) for location services and a plurality of broadcast control parameters; and
a processor configured to:
determine that the broadcast message is ciphered;
in response to determining that the broadcast message is ciphered, determining that the device has at least one key to decipher the ciphered broadcast message; and
decipher the broadcast message using the at least one key and an initial counter, wherein deriving the initial counter comprises:
receive a first value associated with the initial counter using point-to-point mode from the Location Server;
receive a second value associated with the initial counter using broadcast mode from the Location Server; and
derive the initial counter using at least the first value and the second value;
verify a validity of the AD using at least one control parameter from the plurality of broadcast control parameters received from the Location Server.

23. The device of claim 22 , wherein determining that the device has the at least one key to decipher the ciphered broadcast message comprises using a cipher Key ID contained in the at least one control parameter that indicates the at least one key that should be used in deciphering the broadcast message.

24. The device of claim 22 , wherein deciphering

Assignees

• Edge Stephen William
• Fischer Sven
• Hawkes Philip Michael
• Qualcomm Inc

Inventors

• Edge Stephen William
• Fischer Sven
• Hawkes Philip Michael

Classifications

• H04W12/04

  Key management, e.g. using generic bootstrapping architecture [GBA] · CPC title

• G01S19/05

  providing aiding data · CPC title

• H04W12/10

  Integrity · CPC title

• H04W4/02 Primary

  Services making use of location information · CPC title

• H04W4/06 Primary

  Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services · CPC title