Voice and data continuity between wireless devices

• US 10,015,740 B2
• Filed: 09/23/2016
• Issued: 07/03/2018
• Est. Priority Date: 09/30/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Su, Li, Shamim, Tahir, Shi, Jianxiong, Zhang, Wanping
• Primary Examiner(s): LE, THANH C
• Application Number:
  US15/275,292
• Publication Number:
  US 20170094597A1
• Time in Patent Office: 648 Days
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04L 9/0861 Generation of secret information including derivation or calculation of cryptographic keys or passwords
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms
• CPC Class Codes: H04W 12/033 of the user plane, e.g. user's traffic
• CPC Class Codes: H04W 12/037 of the control plane, e.g. signalling traffic
• CPC Class Codes: H04W 12/041 Key generation or derivation
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0209 in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 76/14 Direct-mode setup
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections
• CPC Class Codes: H04W 76/25 Maintenance of established connections
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An accessory wireless device partakes in a data session with a remote device. The data session may be a voice call or other service. To preserve the battery power of the accessory wireless device, the accessory wireless device opportunistically offloads medium-to-long range radio transmission and reception tasks to the companion wireless device while maintaining call continuity. The accessory wireless device and the companion wireless device communicate through a local connection. In one embodiment, the accessory wireless device pushes a wireless wide area network (WWAN) connection to the companion device by sharing selected security and network information with the companion wireless device. When the accessory device and/or the companion device determine that the local connection may not be sustainable, the accessory device pulls the WWAN connection of the companion device back to itself.

Claims

1. A method of maintaining call continuity at a first wireless device, the method comprising:

at the first wireless device;

establishing a radio resource control (RRC) connection to a base station of a wireless wide area network (WWAN);

receiving, from the base station, first data encrypted based on a Cipher Key (CK), wherein a portion of the first data is generated by a remote device;

establishing a local connection to a second wireless device;

sending a signaling message comprising key data to the second wireless device, wherein the key data is based on the CK; and

receiving, from the second wireless device, second data encrypted based on the CK via the local connection.

2. The method of claim 1, wherein the key data comprises one or more of a network access stratum (NAS) encryption key, a NAS integrity key, a user plane integrity key, a user plane encryption key, an RRC integrity key, or an RRC encryption key.

3. The method of claim 1, further comprising:

releasing, subsequent to sending the signaling message to the second wireless device, the RRC connection to the base station.

4. The method of claim 1, further comprising:

receiving, from the base station, a temporary mobile station identifier (TMSI).

5. The method of claim 4, further comprising:

using a secure element, included in the first wireless device, to obtain a first key based on the CK, an integrity key (IK), and a subscriber key (K); and

using the secure element to obtain a second key based on the CK, the IK, and the K.

6. The method of claim 5, wherein the signaling message further comprises the IK, the first key, the second key, and the TMSI.

7. The method of claim 6, wherein:

i) the first key comprises a radio resource control (RRC) encryption key, and ii) the second key comprises a network access stratum (NAS) encryption key.

8. A wireless device comprising:

a memory;

one or more processors; and

a secure element,

wherein the memory includes instructions that when executed by a processor of the one or more processors, cause the wireless device to perform operations comprising;

establishing a radio resource control (RRC) connection to a base station of a wireless wide area network (WWAN);

receiving, from the base station, first data encrypted based on a Cipher Key (CK), wherein a portion of the first data is generated by a remote device;

establishing a local connection to a second wireless device;

sending a signaling message comprising key data to the second wireless device, wherein the key data is based on the CK; and

receiving, from the second wireless device, second data encrypted based on the CK via the local connection.

9. The wireless device of claim 8, wherein the key data comprises one or more of a network access stratum (NAS) encryption key, a NAS integrity key, a user plane integrity key, a user plane encryption key, an RRC integrity key, or an RRC encryption key.

10. The wireless device of claim 8, further comprising:

releasing, subsequent to sending the signaling message to the second wireless device, the RRC connection to the base station.

11. The wireless device of claim 8, further comprising:

receiving, from the base station, a temporary mobile station identifier (TMSI).

12. The wireless device of claim 11, further comprising:

using the secure element to obtain a first key based on the CK, an integrity key (IK), and a subscriber key (K); and

using the secure element to obtain a second key based on the CK, the IK, and the K.

13. The wireless device of claim 12, wherein the signaling message further comprises the IK, the first key, the second key, and the TMSI.

14. The wireless device of claim 13, wherein:

i) the first key comprises a radio resource control (RRC) encryption key, and ii) the second key comprises a network access stratum (NAS) encryption key.

15. A non-transitory computer readable medium comprising instructions that when executed by a processor of a wireless device, cause the wireless device to perform operations comprising:

establishing a radio resource control (RRC) connection to a base station of a wireless wide area network (WWAN);

receiving, from the base station, first data encrypted based on a Cipher Key (CK), wherein a portion of the first data is generated by a remote device;

establishing a local connection to a second wireless device;

sending a signaling message comprising key data to the second wireless device, wherein the key data is based on the CK; and

receiving, from the second wireless device, second data encrypted based on the CK via the local connection.

16. The non-transitory computer readable medium of claim 15, wherein the key data comprises one or more of a network access stratum (NAS) encryption key, a NAS integrity key, a user plane integrity key, a user plane encryption key, an RRC integrity key, or an RRC encryption key.

17. The non-transitory computer readable medium of claim 15, wherein the operations further comprise:

releasing, subsequent to sending the signaling message to the second wireless device, the RRC connection to the base station.

18. The non-transitory computer readable medium of claim 15, wherein the operations further comprise:

receiving, from the base station, a temporary mobile station identifier (TMSI).

19. The non-transitory computer readable medium of claim 18, wherein the operations further comprise:

using the secure element to obtain a first key based on the CK, an integrity key (IK), and a subscriber key (K); and

using the secure element to obtain a second key based on the CK, the IK, and the K.

20. The non-transitory computer readable medium of claim 19, wherein the signaling message further comprises the IK, the first key, the second key, and the TMSI.