# US 2019/0356343 A1 · Systems and Methods for Switching Reference Crystal Oscillators for a Transceiver of a Wireless Device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0356343 A1 - Document ID: US20190356343A1 - Status: Published application - Kind: A1 - Application number: 16/466,902 - Filed: 2016-12-19 - Published: 2019-11-21 - Earliest claimed: 2016-12-19 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Bengt Lindoff; Magnus Åström; Lars Sundström - Web page: https://patentgrep.com/patent/US20190356343A1 ## CPC - H04B 1/005: {adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges} - H04B 1/0082: {with a common local oscillator for more than one band} - H03J 5/00: Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner (H03J7/00, H03J9/00 take precedence; for bandspreading H03J3/10) - H03J 5/242: {used exclusively for band selection} - H03L 7/08: Details of the phase-locked loop - H03L 7/099: concerning mainly the controlled oscillator of the loop - H04B 1/401: for selecting or indicating operating mode - H04B: TRANSMISSION - H03J: TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS - H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B) ## Abstract Systems and methods are disclosed herein that relate to a wireless device that intelligently uses different reference crystal oscillators (XOs) for a PhaseLocked Loop(s) (PLL(s)) in a transceiver of the wireless device. Embodiments of a method of operation of a wireless device comprising a first XO that operates at a first reference frequency and a second XO that operates at a second reference frequency that is greater than the first reference frequency are disclosed. In some embodiments, the method of operation of the wireless devices comprises making a decision as to whether to configure a receiver of the wireless device to use the first XO or the second XO and configuring the receiver of the wireless device to use the first XO or the second XO in accordance with the decision. ## Claims ### Claim at position 1 1-29. (canceled) ### Claim 30 A method of operation of a wireless device comprising a first reference crystal oscillator that operates at a first reference frequency and a second reference crystal oscillator that operates at a second reference frequency that is greater than the first reference frequency, comprising: making a decision as to whether to configure a receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator; and configuring the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator in accordance with the decision. ### Claim 31 (depends on 30) The method of claim 30, wherein upon making the decision to configure the receiver of the wireless device to use the first reference crystal oscillator, the configuring comprises configuring the receiver of the wireless device to use the first reference crystal oscillator. ### Claim 32 (depends on 31) The method of claim 31, wherein configuring the receiver of the wireless device to use the first reference crystal oscillator comprises connecting a phase locked loop of the receiver of the wireless device to the first reference crystal oscillator and configuring the phase locked loop based on the first reference frequency such that a controlled oscillator that is controlled by the phase locked loop provides an output signal at a desired local oscillator frequency. ### Claim 33 (depends on 31) The method of claim 31, further comprising, upon making the decision to configure the receiver of the wireless device to use the first reference crystal oscillator, activating the first reference crystal oscillator prior to configuring the receiver of the wireless device to use the first reference crystal oscillator. ### Claim 34 (depends on 31) The method of claim 31, further comprising, upon making the decision to configure the receiver of the wireless device to use the first reference crystal oscillator, deactivating the second reference crystal oscillator if the second reference crystal oscillator is active after configuring the receiver of the wireless device to use the first reference crystal oscillator. ### Claim 35 (depends on 30) The method of claim 30, wherein upon making the decision to configure the receiver of the wireless device to use the second reference crystal oscillator, the configuring comprises configuring the receiver of the wireless device to use the second reference crystal oscillator. ### Claim 36 (depends on 35) The method of claim 35, wherein configuring the receiver of the wireless device to use the second reference crystal oscillator comprises connecting a phase locked loop of the receiver of the wireless device to the second reference crystal oscillator and configuring the phase locked loop based on the second reference frequency such that a controlled oscillator that is controlled by the phase locked loop provides an output signal at a desired local oscillator frequency. ### Claim 37 (depends on 35) The method of claim 35, further comprising, upon making the decision to configure the receiver of the wireless device to use the second reference crystal oscillator, activating the first reference crystal oscillator and activating the second reference crystal oscillator prior to configuring the receiver of the wireless device to use the second reference crystal oscillator. ### Claim 38 (depends on 35) The method of claim 35, further comprising, upon making the decision to configure the receiver of the wireless device to use the second reference crystal oscillator, causing adaptation of the second reference crystal oscillator based on an output of the first reference crystal oscillator. ### Claim 39 (depends on 38) The method of claim 38, wherein the first reference crystal oscillator was previously tuned during a synchronization process in which the wireless device was synchronized to a radio access node in a wireless communication system. ### Claim 40 (depends on 35) The method of claim 35, further comprising, upon making the decision to configure the receiver of the wireless device to use the second reference crystal oscillator, deactivating the first reference crystal oscillator. ### Claim 41 (depends on 30) The method of claim 30, further comprising: detecting an event that that may trigger a change in which one of the first reference crystal oscillator and the second reference crystal oscillator is used by the receiver of the wireless device; and making the decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator comprises making the decision upon detecting the event. ### Claim 42 (depends on 30) The method of claim 30, wherein making the decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator comprises making the decision based on whether or not the wireless device is synchronized to a wireless network, wherein the decision is to use the first reference crystal oscillator if the wireless device is not synchronized to a wireless network and the decision is to use the second reference crystal oscillator if the wireless device is synchronized to a wireless network. ### Claim 43 (depends on 30) The method of claim 30, further comprising: activating the first reference crystal oscillator; configuring the receiver of the wireless device to use the first reference crystal oscillator; configuring the receiver of the wireless device to operate at a carrier frequency; and performing an initial cell search at the carrier frequency; wherein making the decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator comprises determining whether a synchronization signal was detected while performing the initial cell search at the carrier frequency such that the decision is to continue to use the first reference crystal oscillator if a synchronization signal was not detected and to use the second reference crystal oscillator if a synchronization signal was detected. ### Claim 44 (depends on 43) The method of claim 43, further comprising, upon determining that a synchronization signal was detected while performing the initial cell search at the carrier frequency: adapting the first reference crystal oscillator and/or a phase locked loop that generates a local oscillator signal for the receiver of the wireless device based on the output of the first reference crystal oscillator to synchronize to a wireless network; activating the second reference crystal oscillator; and adapting the second reference crystal oscillator based on the first reference crystal oscillator; wherein configuring the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator in accordance with the decision comprises configuring the receiver of the wireless device to use the second reference crystal oscillator after adapting the second reference crystal oscillator. ### Claim 45 (depends on 44) The method of claim 44, further comprising, upon determining that a synchronization signal was detected while performing the initial cell search at the carrier frequency, disabling the first reference crystal oscillator. ### Claim 46 (depends on 43) The method of claim 43, wherein making the decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator comprises making the decision based on a connection state of the wireless device with respect to a wireless network. ### Claim 47 (depends on 46) The method of claim 46, wherein making the decision based on the connection state of the wireless device with respect to a wireless network comprises making the decision to use the first reference crystal oscillator if the connection state of the wireless device is an idle state and making the decision to use the second reference crystal oscillator if the connection state of the wireless device is a connected state. ### Claim 48 (depends on 30) The method of claim 30, wherein making the decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator comprises making the decision based on a carrier frequency of a signal to be received by the receiver the wireless device, wherein making the decision comprises making the decision to use the first reference crystal oscillator if the carrier frequency is less than a predefined or preconfigured threshold and making the decision to use the second reference crystal oscillator if the carrier frequency is greater than the predefined or preconfigured threshold. ### Claim 49 (depends on 48) The method of claim 48, wherein the predefined or preconfigured threshold is greater than or equal to 4 gigahertz (GHz). ### Claim 50 (depends on 48) The method of claim 48, wherein the predefined or preconfigured threshold is greater than or equal to 10 gigahertz (GHz). ### Claim 51 (depends on 30) The method of claim 30, wherein the first reference frequency is less than or equal to 52 megahertz (MHz), and the second reference frequency is greater than or equal to 100 MHz. ### Claim 52 (depends on 30) The method of claim 30, wherein the wireless device comprises at least two receivers, and: making the decision comprises making the decision as to which receiver of the at least two receivers to use and whether to configure the decided receiver to use the first reference crystal oscillator or the second reference crystal oscillator based on a carrier frequency of a signal to be received by the wireless device; and configuring the receiver of the wireless device comprises configuring the decided receiver to use the first reference crystal oscillator or the second reference crystal oscillator in accordance with the decision. ### Claim 53 A wireless device comprising a first reference crystal oscillator that operates at a first reference frequency and a second reference crystal oscillator that operates at a second reference frequency that is greater than the first reference frequency, the wireless device comprising: a receiver; and control circuitry configured to: make a decision as to whether to configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator; and configure the receiver of the wireless device to use the first reference crystal oscillator or the second reference crystal oscillator in accordance with the decision.