# US 8,570,890 B2 · Mobile radio communications device and related method of operation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,890 B2 - Document ID: US8570890B2 - Status: Granted - Kind: B2 - Application number: 13/000,851 - Filed: 2009-06-18 - Published: 2011-05-19 - Granted: 2013-10-29 - Earliest claimed: 2008-07-02 - Assignees: NEC Corporation - Applicants: Weili Ren; Michael Nosley - Inventors: Weili Ren; Michael Nosley - Web page: https://patentgrep.com/patent/US8570890B2 ## CPC - H04W 56/00: Synchronisation arrangements - H04B 7/2681: {Synchronisation of a mobile station with one base station} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract A mobile station establishes UL synchronization by the use of downlink preamble messages, and by monitoring timing drift within the downlink signalling and by updating the UL synchronization value responsive to the magnitude of the timing drift exceeding a threshold value. Tx power values can also be updated as a function of the updated synchronization value. ## Claims ### Claim 1 A method of controlling uplink (UL) synchronisation in a mobile station of a radio communications network, and including the steps of monitoring timing drift within downlink (DL) signalling and updating an uplink synchronisation value to obtain an update uplink synchronization value, in response to the said timing drift exceeding a threshold value; wherein the update uplink synchronisation value is determined on the basis of the sum of a previous synchronisation value and twice the aforementioned magnitude of the said timing drift in the DL signalling. ### Claim 2 (depends on 1) A method as claimed in claim 1, wherein the threshold value is transmitted by way of Downlink Channel Descriptor (DCD) signalling. ### Claim 3 (depends on 2) A method as claimed in claim 2, wherein the threshold value is determined at a base station within the radio communications network and responsive to at least cell size, cyclic prefix length and measurement accuracy. ### Claim 4 A method of determining an update synchronization value for uplink synchronisation in a mobile radio communications network and having regard to a current synchronisation value, including the step of determining timing drift within downlink signalling and wherein the update synchronisation value comprises the sum of the said current synchronisation value and twice the magnitude of the said timing drift. ### Claim 5 (depends on 1) A method as claimed in claim 1, wherein the timing drift is determined on the basis of DL preamble measurements. ### Claim 6 A method of controlling a Tx power value in a mobile station in a radio communications network, including the step of monitoring timing drift within downlink (DL) signalling, updating an uplink synchronization value, and determining the updated uplink synchronisation value on the basis of the sum of a previous synchronization value and twice the magnitude of timing drift in the signalling and wherein the updated Tx power value comprises a function of the said update uplink synchronisation value. ### Claim 7 (depends on 6) A method as claimed in claim 6, wherein the Tx update value is determined whenever the uplink synchronisation value is updated. ### Claim 8 (depends on 1) A method as claimed in claim 1 and provided within a WiMAX system. ### Claim 9 (depends on 1) A method as claimed in claim 1, where the network signalling arises in Time Division Duplex mode. ### Claim 10 A mobile radio communications device for use within a mobile radio communications network and arranged for controlling uplink synchronisation values, and including: a section which monitors a downlink timing drift value; a section which updates the uplink synchronisation value to obtain an update uplink synchronization value, in response to the magnitude of the downlink timing drift value exceeding a threshold value; and a section which determines the update uplink synchronisation value on the basis of the sum of a previous uplink synchronization value and twice the said magnitude of the downlink timing drift. ### Claim 11 A mobile radio communications device for use in a mobile radio communications network and arranged for determining an update synchronization value for uplink synchronisation and including means for determining the magnitude of downlink timing drift and wherein the update synchronisation value is determined on the basis of the sum of a previous synchronisation value for the uplink synchronization and twice the magnitude of the said timing drift. ### Claim 12 (depends on 10) A device as claimed in claim 10, and including means for determining an updated Tx power value as a function of the update uplink synchronisation value. ### Claim 13 (depends on 12) A device as claimed in claim 12 and arranged for updating the Tx power value when the uplink synchronisation value updates. ### Claim 14 (depends on 10) A device as claimed in claim 10, and arranged such that the timing drift is determined on the basis of downlink preamble measurements. ### Claim 15 (depends on 4) A method as claimed in claim 4, wherein the timing drift is determined on the basis of DL preamble measurements. ### Claim 16 A method of controlling a Tx power value in a mobile station in a radio communications network, including the step of determining timing drift within downlink signalling and determining an update uplink synchronisation value on the basis of the sum of a current synchronization value and twice the magnitude of the said timing drift, and wherein the updated Tx power value comprises a function of the said update uplink synchronisation value. ### Claim 17 (depends on 16) A method as claimed in claim 16, wherein the Tx update value is determined whenever the uplink synchronisation value is updated. ### Claim 18 (depends on 4) A method as claimed in claim 4 and provided within a WiMAX system. ### Claim 19 (depends on 4) A method as claimed in claim 4, where the network signalling arises in Time Division Duplex mode.