Method and system for maintaining uplink synchronization with peer-to-peer communication in wireless communication system

• US 20060166688A1
• Filed: 03/01/2004
• Published: 07/27/2006
• Est. Priority Date: 03/07/2003
• Status: Active Grant

• Current Assignee: Uniloc 2017 LLC (SoftBank Group Corp.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Du, Yonggang, Sun, Li, Ma, Ni, Zhang, Xuejun, Cheng, Jiang, Jia, Qunli
• Granted Patent: US 7,286,841 B2
• Time in Patent Office: Days
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04W 52/383 power control in peer-to-peer links
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time

Abstract

A method is proposed for maintaining uplink synchronization with P2P communication in wireless communication networks, comprising steps of: the wireless communication system overhears the P2P communication between two UEs (user equipments), determines the SS (synchronization shift) information of said UEs according to the overheard information transferred by each UE in P2P communication, and transmits the SS information to the corresponding UE via the downlink common control channel; the UE monitors the downlink common control channel, and adjusts the TA (timing advance) for transmitting signals according to the SS information transferred via the downlink common control channel.

Claims

1. A method for wireless communication systems to maintain uplink synchronization in P2P communication, comprising:

overhearing the P2P communication between two UEs (user equipments);

computing the characteristic parameter of each UE according to the overheard information transferred by each UE during P2P communication;

determining the SS (synchronization shift) information of each UE according to the computed characteristic parameter of each UE; and

transmitting the determined SS information to the corresponding UE via the downlink common control channel so that said UE can maintain uplink synchronization.

2. The method for maintaining uplink synchronization in P2P communication according to claim 1 wherein said computed characteristic parameter of each UE is the midamble information in the traffic burst structure.

3. The method for maintaining uplink synchronization in P2P communication according to claim 1, further comprising:

setting a time limit for sending a P2P poll message to the UE via said downlink common control channel when the time during which the wireless communication system can'"'"'t overhear said P2P communication exceeds the time limit, so that the UE can adjust its transmission power according to the poll message.

4. The method for maintaining uplink synchronization in P2P communication according to claim 3, further comprising:

resending a poll message to the UE so that the UE can adjust its transmission power according to the poll message, when the wireless communication system can'"'"'t yet overhear said P2P communication within said time limit after the UE adjusts its transmission power.

5. The method for maintaining uplink synchronization in P2P communication according to claim 4, further comprising:

setting the number of sending P2P poll messages to the UE by the wireless communication system; and

sending an uplink synchronization reestablishment indication to each UE via said downlink common control channel, when the number of sending communication poll messages to the UE by the wireless communication system exceeds the set maximum value.

6. The method for maintaining uplink synchronization in P2P communication according to claim 4, wherein said uplink synchronization reestablishment indication is sent to each UE via said downlink common control channel when the transmission power adjusted by the UE reaches a set value.

7. The method for maintaining uplink synchronization in P2P communication according to claim 1, wherein said downlink common control channel is the paging control channel.

8. A method for a UE to maintain uplink synchronization in P2P communication, comprising:

monitoring the downlink common control channel;

receiving the SS information transferred via the downlink common control channel; and

adjusting the TA (timing advance) for the UE to transmit signals according to the received SS information.

9. The method for maintaining uplink synchronization in P2P communication according to claim 8, further comprising:

receiving the P2P poll message transferred via said downlink common control channel; and

adjusting the transmission power according to the received poll message.

10. The method for maintaining uplink synchronization in P2P communication according to claim 8, further comprising:

receiving the uplink synchronization reestablishment indication transferred via said downlink common control channel; and

reestablishing uplink synchronization according to the uplink synchronization reestablishment indication.

11. The method for maintaining uplink synchronization in P2P communication according to claim 8, wherein said downlink common control channel is the paging control channel.

12. An system for wireless communication systems to maintain uplink synchronization in P2P communication, comprising:

an overhearing unit, for overhearing the P2P communication between two UEs;

a computing unit, for computing the characteristic parameter of each UE according to the overheard information transferred by each UE in P2P communication;

an SS information generating unit, for determining the SS information of the UE according to the computed characteristic parameter of each UE; and

a transmitting unit, for transmitting the determined SS information to the corresponding UE via the downlink common control channel so that the UE can maintain uplink synchronization.

13. The system for maintaining uplink synchronization in P2P communication according to claim 12, wherein said characteristic parameter is the midamble information in the traffic burst structure.

14. The system for maintaining uplink synchronization in P2P communication according to claim 12, further comprising:

a timer, for setting the time limit in which the wireless communication system can'"'"'t overhear said P2P communication; and

a poll message sending unit, for sending a P2P poll message to the UE via said downlink common control channel so that the UE can adjust its transmission power according to the poll message when the time during which the wireless communication system can'"'"'t overhear said P2P communication exceeds the time limit of the timer.

15. The system for maintaining uplink synchronization in P2P communication according to claim 14, further comprising:

a counter, for counting the number of sending P2P poll messages to the UE by the wireless communication system.

16. The system for maintaining uplink synchronization in P2P communication according to claim 15, further comprising:

a synchronization reestablishing indication sending unit, for sending uplink synchronization reestablishment indications via said downlink common control channel to each UE, when the counted number in the counter exceeds a predefined value or the transmission power adjusted by the UE reaches a set value.

17. The system for maintaining uplink synchronization in P2P communication according to any claim from 12, wherein said downlink common control channel is the paging control channel.

18. A UE, comprising:

a transceiver, for receiving or transmitting radio signals;

a monitoring unit, for monitoring the downlink common control channel;

a receiving unit, for receiving the SS information transferred via the downlink common control channel; and

an adjusting unit, for adjusting the TA for the UE to transmit signals according to the received SS information.

19. The UE according to claim 18, further comprising:

a poll message receiving unit, for receiving the P2P poll message transferred via said downlink common control channel; and

a power adjusting unit, for adjusting the transmission power according to the received poll message.

20. The UE according to claim 18, further comprising:

a synchronization reestablishing indication receiving unit, for receiving an uplink synchronization reestablishment indication transferred via said downlink common control channel; and

an uplink synchronization reestablishing unit, for reestablishing uplink synchronization according to the uplink synchronization reestablishment indication.

21. The UE according to claim 18, 19 or 20, wherein said downlink common control channel is the paging control channel.