METHOD AND APPARATUS FOR CONTROLLING UPLINK TRANSMISSION TIMING IN A COMMUNICATION NETWORK

• US 20090111445A1
• Filed: 10/29/2007
• Published: 04/30/2009
• Est. Priority Date: 10/29/2007
• Status: Abandoned Application

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Xiao, Weimin, Ghosh, Amitava, Ratasuk, Rapeepat, Filipovich, Igor
• Application Number:
  US11/926,859
• Publication Number:
  US 20090111445A1
• Time in Patent Office: Days
• US Class Current: 455/418
• CPC Class Codes: H04B 7/2662 Arrangements for Wireless System Synchronisation
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A method and corresponding system for controlling uplink timing in a communication network (100) is described. The method comprises of scheduling a mobile device (104) to transmit a preamble over a physical random access channel. The mobile device (104) is scheduled to transmit the preamble over a physical random access channel at a selected random access slot. The method then includes receiving the preamble transmitted by the scheduled mobile device (104). The preamble is received over the physical random access channel. The method further comprises measuring a timing offset at which the preamble is received from the scheduled mobile device (104) and determining a timing adjustment value in uplink transmission timing based on the measured timing offset. The method then comprises transmitting a timing advance command comprising the determined timing adjustment value in a control message to the mobile device (104) for controlling uplink transmission timing at the mobile device (104).

Claims

1. A method for controlling uplink transmission timing in a communication network the method comprising:

at a node of the communication network;

scheduling a mobile device to transmit a preamble over a physical random access channel, wherein the preamble is associated with an uplink transmission signal at the mobile device;

receiving the preamble transmitted by the scheduled mobile device over the physical random access channel;

measuring a timing offset at which the preamble is received from the scheduled mobile device;

determining a timing adjustment value in uplink transmission timing based on the measured timing offset; and

transmitting a timing advance command comprising the determined timing adjustment value to the mobile device for controlling uplink transmission timing at the mobile device.

2. The method of claim 1, wherein the preamble is a dedicated preamble allocated by the node to the mobile device.

3. The method of claim 2, wherein the dedicated preamble is one of a set of preambles reserved for measuring uplink transmission timing of the mobile device.

4. The method of claim 3, wherein the set of dedicated preambles is reserved by broadcasting the set of dedicated preambles from the node to a plurality of mobile devices in the communication network to enable the mobile devices to which the preamble is not allocated to refrain from selecting the dedicated preamble.

5. The method of claim 1, wherein the preamble is randomly selected from a plurality of preambles by the scheduled mobile device.

6. The method of claim 1, wherein the timing advance command is transmitted in a control message.

7. The method of claim 6, wherein the control message is an uplink scheduling grant or downlink assignment message.

8. The method of claim 1, wherein scheduling the mobile device comprises scheduling the mobile device to transmit the preamble periodically at a selected random access time and frequency slot.

9. The method of claim 1, wherein scheduling the mobile device comprises scheduling the mobile device to transmit the preamble based on at least one of a past timing advance command, past update interval, timer expiration, a cell layout, or mobility of the mobile device.

10. The method of claim 1, wherein the node comprises a base station.

11. A method for transmitting timing advance command for controlling uplink transmission timing in a communication network, the method comprising:

at a node of the communication network;

encapsulating the timing advance command in a control message;

modifying the control message to indicate the presence of the timing advance command in the control message; and

transmitting the control message comprising the timing advance command for controlling uplink transmission timing at the mobile device.

12. The method of claim 11, wherein modifying the control message comprises assigning an unused field of the control message to indicate the presence of the timing advance command in the control message.

13. The method of claim 12, wherein assigning the unused field comprises modifying the values in the unused field to indicate the presence of the timing advance command in the control message.

14. A method for controlling uplink transmission timing in a communication network, the method comprising:

at a mobile device of the communication network;

receiving a preamble allocated by a node, wherein the preamble is associated with an uplink transmission signal;

transmitting the preamble over a physical random access channel;

receiving a timing advance command in response to the transmitted preamble, wherein the timing advance command includes a timing adjustment value in uplink transmission timing; and

controlling uplink transmission timing based on the received timing advance command.

15. The method of claim 14, wherein the preamble is a dedicated preamble allocated to the mobile device;

16. The method of claim 14, wherein the preamble is transmitted when the mobile device is scheduled by the node to transmit the preamble.

17. The method of claim 14, wherein the timing advance command is received in a control message.

18. The method of claim 17, wherein the control message is an uplink scheduling grant or downlink assignment message.

19. The method of claim 14 wherein receiving a timing advance command further comprises:

determining whether the timing advance command is present in the control message; and

extracting the timing advance command from the control message before the step of controlling the uplink transmission timing.

20. The method of claim 19, wherein the presence of timing advance command in the control message is determined based on the values in an unused field in the control message.

21. The method of claim 20, wherein the values in the unused field is modified to exhibit the presence of timing advance command in the control message.

22. The method of claim 14, wherein the mobile device comprises a radio.

23. A system for controlling uplink transmission timing in a communication network, the system comprising:

a node establishing communication with a mobile device, the node comprising;

an assigning module to allocate a preamble to the mobile device, wherein the preamble is associated with an uplink transmission signal at the mobile device;

a scheduling module to schedule the mobile device to transmit the preamble over a physical random access channel; and

a processor communicatively coupled between the assigning module and the scheduling module, the processor operable to measure a timing offset at which the preamble is received from the scheduled mobile device; and

operable to determine a timing adjustment value in uplink transmission timing based on the measured timing offset; and

a transceiver for transmitting the determined timing adjustment value to the mobile device for controlling uplink transmission timing at the mobile device.

24. The system of claim 23, wherein the assigning module reserves the preamble as a dedicated preamble to the mobile device.

25. The system of claim 23 further comprising a timer coupled to the processor for monitoring the timing offset at which the preamble is received from the mobile device.

26. The system of claim 23 further comprising a memory coupled to the scheduling module for storing at least one of a past timing advance command, past update time interval, a cell layout, a timer expiration information, or mobility information of the mobile device.

27. The system of claim 23, wherein the processor is operable to modify the values in an unused field of the control message to indicate the presence of determined timing adjustment value in the control message.