Timing advance enhancements for cellular communications
View Patent ↗Example methods and apparatus to implement timing advance enhancements for cellular communications are disclosed. A disclosed example method to communicate over a cellular network by a device involves retrieving a stored timing advance value and determining if the stored timing advance value is valid based at least on whether the device is operating in a stationary mode. When the stored timing advance is valid, a contention-based transmission is transmitted to a network using the stored timing advance value in order to compensate for propagation delay.
1. A method to communicate over a cellular network by a device, comprising:
retrieving a stored timing advance value;
determining if the stored timing advance value is valid based at least on whether the device is operating in a stationary mode in which the device transmits using a previously stored timing advance value without failing; and
when the stored timing advance is valid, transmitting a contention-based transmission to a network using the stored timing advance value in order to compensate for propagation delay.
2. The method of claim 1 further comprising transmitting bursts of data using the stored timing advance value when responding to a paging message or a channel assignment message received from the network when the timing advance value is valid based at least on whether the device is operating in the stationary mode.
3. The method of claim 1 further comprising:
when the device is operating in a moving mode:
initiating access to the network by transmitting a channel request message to the network using an access burst with a zero or otherwise specified timing advance value over a random access channel (RACH),
receiving from the network an access grant message with a calculated timing advance value and assignment of one or more logical channels for further communications,
storing the calculated timing advance value, and
continuing communications over the assigned channels using the stored timing advance value or a timing advance value updated during communications with the network; and
when the device is operating in the stationary mode:
initiating access to the network by transmitting a channel request message to the network over the RACH or other control channel using a previously stored timing advance value,
receiving from the network an access grant message and assignment of one or more logical channels for further communications, and
continuing communications over the assigned channels using the stored timing advance value.
4. The method of claim 3 wherein the access burst, during the moving mode, has a longer guard interval and shorter data field than the channel request message, during the stationary mode.
5. The method of claim 1 further comprising operating in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified number of attempts to access the network in the stationary mode have failed.
6. The method of claim 1 further comprising operating in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified time interval has elapsed since the timing advance value was stored.
7. The method of claim 1 further comprising operating in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified time interval has elapsed since the last successful data transfer.
8. The method of claim 1 further comprising switching to the moving mode for the next network access in order to receive an updated timing advance value upon a device reset, a device power cycle event, or upon receipt of a command from a user interface.
9. The method of claim 1 further comprising, when the device is operating in the stationary mode and in a ready state and is attached to the network in a ready state, receiving an immediate assignment of a downlink channel from the network and transmitting a request for an uplink channel with the stored timing advance value.
10. The method of claim 1 further comprising, when the device is operating in the stationary mode and in a standby state and is attached to the network, receiving a paging message with an immediate assignment of a downlink channel from the network and transmitting a request for an uplink channel with the stored timing advance value.
11. The method of claim 1 further comprising, when the device is operating in the stationary mode, performing periodic cell update procedures by communicating with the network.
12. The method of claim 1 further comprising operating in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode upon detecting an indication that movement relative to the network has occurred using one or more techniques selected from a group that includes: detecting movement of the device relative to the network from measurements of signals transmitted by neighboring cells, detecting movement of the device relative to the network from accelerometer signals, and detecting movement of the device relative to the network using a global positioning system (GPS) unit to determine a location of the device when the timing advance is stored and before a network access is initiated.
13. A computer readable storage memory having instructions stored thereon that, when executed, cause a machine to implement the method as defined in claim 1 .
14. A mobile station (MS) for communicating over a cellular network, comprising:
a processor configured to:
retrieve a stored timing advance value;
determine if the stored timing advance value is valid based at least on whether the mobile station is operating in a stationary mode in which the mobile station transmits using a previously stored timing advance value without failing; and
when the stored timing advance is valid, transmitting a contention-based transmission to a network using the stored timing advance value in order to compensate for propagation delay.
15. The mobile station of claim 14 wherein the processor is further configured to transmit bursts of data using the stored timing advance value when responding to a paging message or a channel assignment message received from the network when the timing advance value is valid based at least on whether the mobile station is operating in the stationary mode.
16. The mobile station of claim 14 wherein the processor is further configured to:
when the mobile station is operating in a moving mode:
initiate access to the network by transmitting a channel request message to the network using an access burst with a zero or otherwise specified timing advance value over a random access channel (RACH) defined by the network,
receive from the network an access grant message with a calculated timing advance value and assignment of one or more logical channels for further communications,
store the calculated timing advance value, and
continue communications over the assigned channels using the stored timing advance value or a timing advance value updated during communications with the network; and
when the mobile station is operating in the stationary mode:
initiate access to the network by transmitting a channel request message to the network over the RACH or other control channel using a previously stored timing advance value,
receive from the network an access grant message and assignment of one or more logical channels for further communications, and
continue communications over the assigned channels using the stored timing advance value.
17. The mobile station of claim 16 wherein the access burst, during the moving mode, has a longer guard interval and shorter data field than the channel request message, during the stationary mode.
18. The mobile station of claim 14 wherein the processor is further configured to operate in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified number of attempts to access the network in the stationary mode have failed.
19. The mobile station of claim 14 wherein the processor is further configured to operate in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified time interval has elapsed since the timing advance value was stored.
20. The mobile station of claim 14 wherein the processor is further configured to operate in the stationary mode in preference to a moving mode if a calculated timing advance value has been previously stored and to revert to the moving mode if a specified time interval has elapsed since the last successful data transfer.
21. The mobile station of claim 14 wherein the processor is further configured to switch to a moving mode for the next network access in order to receive an updated timing advance value upon a device reset, a device power cycle event, or upon receipt of a command from a user interface.