CN108605360B - Timing advance value protection in mobile devices - Google Patents

Abstract

A method for initiating a timing advance protection window on a mobile communication device may comprise: determining an uplink transmission interval for a first subscription of a mobile communication device; determining an adjustment threshold based on the uplink transmission interval; and incrementing a timing advance adjustment counter by a timing advance adjustment value received from the first network. The mobile communication device can determine whether an absolute value of the timing advance adjustment counter exceeds an adjustment threshold and ignore the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

Description

Timing advance value protection in mobile devices

Technical Field

The disclosure herein relates generally to wireless communications, and more specifically to techniques for initiating a timing advance protection window on a mobile communication device.

Background

Some designs of mobile communication devices, such as smart phones, tablet computers, and laptop computers, contain one or more Subscriber Identity Module (SIM) cards that provide users with access to multiple separate mobile phone networks. Examples of mobile phone networks include third generation (3G), fourth generation (4G), Long Term Evolution (LTE), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), CDMA 2000, wideband CDMA (wcdma), global system for mobile communications (GSM), single carrier radio transmission technology (1 xRTT), and Universal Mobile Telecommunications System (UMTS). The SIM may communicate with its corresponding network using a particular Radio Access Technology (RAT).

A wireless communication device that includes one or more SIMs and connects to two or more separate mobile phone networks supporting two or more subscriptions using one or more shared Radio Frequency (RF) resources/radio units may be referred to as a multi-subscription multi-standby (MSMS) communication device. One example of an MSMS device is a Dual SIM Dual Standby (DSDS) communication device that includes two SIM cards supporting two or more subscriptions, each subscription associated with a separate Radio Access Technology (RAT). In a DSDS communication device, separate subscriptions share one RF resource (sometimes referred to as a chain of RF resources) to communicate with two separate mobile telephone networks on behalf of their respective subscriptions. While one subscription is using RF resources, the other subscription is in standby mode and cannot communicate using RF resources.

One result of having multiple subscriptions that simultaneously maintain network connectivity is that these subscriptions can sometimes interfere with each other's communications. For example, two subscriptions on a DSDS communication device communicate with their respective mobile telephone networks using a shared RF resource, and one subscription may communicate with the subscribed mobile network using the RF resource at a time. Even if the subscription is in an "idle-standby" mode, meaning that the subscription is not actively communicating with the network, the subscription may still need to periodically receive access to the shared RF resources in order to perform various network operations. For example, idle subscriptions may require shared RF resources at regular intervals to perform idle mode operations to receive network paging messages in order to remain connected to the network.

In conventional multi-SIM communication devices, subscriptions that actively use RF resources shared with idle subscriptions may occasionally be forced to interrupt RF operation of the active subscriptions so that the idle subscriptions may use the shared RF resources to perform idle-standby mode operations (e.g., paging monitoring, cell reselection, system information monitoring, etc.) of the idle subscriptions. This process of switching access to a shared RF resource from an active subscription to an idle subscription is sometimes referred to as "tune away" because the RF resource tunes away from and to the frequency band or channel of the active subscription. After the idle subscription completes network communications, access to the RF resources may be switched from the idle subscription to the active subscription through a "tune-back" operation. However, tune away may lead to timing advance coordination issues between active subscriptions and their associated networks.

Disclosure of Invention

Various examples of methods for initiating a timing advance protection window on a mobile communication device may include: the method includes determining an uplink transmission interval for a first subscription of a mobile communication device, determining an adjustment threshold based on the uplink transmission interval, incrementing a timing advance adjustment counter by a timing advance adjustment value received from a first network, determining whether an absolute value of the timing advance adjustment counter exceeds the adjustment threshold, and ignoring the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

Some example methods may further include: adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter does not exceed the adjustment threshold. Some example methods may further include: determining whether the uplink transmission interval is within a predetermined range; and adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the uplink transmission interval is not within the predetermined range.

Some example methods may further include: determining, in response to a transmission sent from the first subscription to the first network, whether the first subscription has received a predetermined response pattern from the first network; and adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the first subscription has received the predetermined response pattern from the first network. In some examples, the predetermined response pattern may be a threshold number of consecutive acknowledgements.

Some example methods may further include: determining whether a timing advance guard window period has expired; and adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the timing advance protection window time period has expired. In some examples, the timing advance protection window period may be a sum of an inactivity timer of the first subscription and a period of a short discontinuous reception cycle.

Some example methods may further include: determining whether a tune away has been initiated from the first subscription to a second subscription of the mobile communication device, and initiating a new timing advance protection window time period in response to determining that the tune away has been initiated. Some example methods may further include: determining whether the uplink transmission interval is within a predetermined range, and extending the new timing advance protection window time period in response to determining that the uplink transmission interval is within the predetermined range. In some examples, the new timing advance protection window period may be extended by a sum of the inactivity timer of the first subscription and a period of a short discontinuous reception cycle. Some example methods may further include: determining whether the uplink transmission interval exceeds a predetermined upper limit, and adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval exceeds the predetermined upper limit.

In some examples, determining the adjustment threshold may also be based on an estimated velocity of the mobile communication device. Some example methods may further include: determining the uplink transmission interval for each of a plurality of timing advance groups, wherein each timing advance group comprises one or more component carriers of the first subscription; determining the adjustment threshold based on the uplink transmission interval for each of the plurality of timing advance groups; incrementing the timing advance adjustment counter by the timing advance adjustment value received from the first network for each of the plurality of timing advance groups; determining, for each of the plurality of timing advance groups, whether the absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and ignoring the timing advance adjustment value for any timing advance group of the plurality of timing advance groups for which the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

Further examples include a mobile communication device comprising a memory, a Radio Frequency (RF) resource, and a processor configured to perform operations of the methods described herein. Further examples include a non-transitory processor-readable storage medium having stored thereon processor-executable software instructions configured to cause a processor of a mobile communication device to perform operations of the methods described herein. Further examples include mobile communication devices comprising means for performing the functions of the operations of the methods described herein.

Drawings

The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate examples and, together with the general description given above and the detailed description given below, serve to explain features of the disclosed systems and methods.

Fig. 1 is a block diagram of a communication system suitable for use in various exemplary mobile telephone networks.

Fig. 2 is a component block diagram of a multi-SIM communication device, according to various examples.

Fig. 3 is a timing diagram illustrating operation of timing advance for a mobile communication device communicating with a network base station.

Fig. 4 is a timing diagram illustrating an error in determining timing advance for a mobile communication device communicating with a network base station.

Fig. 5A and 5B are timing diagrams illustrating a timing advance protection window with advance termination according to various examples.

Fig. 6 is a timing diagram illustrating a tune-away triggered timing advance protection window, according to various examples.

Fig. 7 is a process flow diagram illustrating a method for initiating a timing advance protection window on a mobile communication device, in accordance with various examples.

Fig. 8 is a process flow diagram illustrating a method for initiating a tune away triggered timing advance protection window on a mobile communication device in accordance with various examples.

Fig. 9 is a component block diagram of a mobile communication device suitable for implementing some example methods.

Detailed Description

Various examples will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References to specific examples and implementations are for illustrative purposes, and are not intended to limit the scope of the written description or claims.

As used herein, the terms "mobile communication device," "multi-SIM communication device," or "multi-SIM device" refer to any one or all of cellular telephones, smart phones, personal or mobile multimedia players, personal data assistants, laptop computers, tablet computers, smart books, smart watches, palmtop computers, wireless email receivers, multimedia internet cellular telephones, wireless game controllers, and similar personal electronic devices that include one or more SIM modules (e.g., SIM cards), programmable processors, memory, and circuitry for connecting to at least two mobile communication networks using one or more shared RF resources. Various examples may be useful in mobile communication devices such as smart phones, and thus reference is made to such devices in the description of the various examples. However, these examples may be useful in any electronic device that may separately maintain multiple RATs utilizing at least one shared RF chain, which may include one or more of an antenna, a radio, a transceiver, and so forth. The multi-SIM communication device may be configured to operate in a DSDS mode.

As used herein, the terms "SIM module," "SIM card," and "subscriber identification module" may be used interchangeably to refer to a memory module, which may be an integrated circuit or may be embedded in a removable card and store an International Mobile Subscriber Identity (IMSI), related keys, and/or other information used to identify and/or authenticate a multi-standby communication device on a network and enable communication services with the network. Because the information stored in the SIM enables the multi-SIM communication device to establish a communication link for a particular communication service with a particular network, the term "subscription" is used herein as a shorthand reference to refer to a communication service associated with and implemented through information stored as a SIM and a communication network in a particular SIM, and services and subscriptions supported by that network, relative to one another.

In the following description of various examples, reference is made to a first subscription and a second subscription. The references to the first subscription and the second subscription are arbitrary and are used only for the purpose of describing examples. The device processor may assign any designator, name, or other designation to distinguish subscriptions on the mobile communication device.

The network base station can utilize the timing advance value to coordinate communications with mobile communication devices that reside on the base station. For example, a base station may communicate with two mobile communication devices, one located at the base station and the other located five kilometers from the base station. Uplink communications sent by mobile communication devices at the base station are received by the base station almost instantaneously. However, due to the distance traveled by the uplink signal, uplink communications transmitted by mobile communication devices that are five kilometers away arrive at the base station after a certain delay period.

A network base station typically allocates a particular time slot in which to receive communications from each mobile communication device that is resident on the base station. The base station receives communications from each mobile communication device without collision if all mobile communication devices are the same distance from the base station. However, when the mobile communication devices are at different distances from the base station, the base station may receive uplink communications for one mobile communication device before the base station completes receiving uplink communications for another device. The timing advance value is used by the mobile communication device to adjust for signal propagation delay due to the distance between the mobile communication device and the base station. The timing advance may also counteract many other factors that affect uplink timing, including changes in propagation environment, oscillation drift in the mobile communication device, and other RF propagation effects independent of transmission distance.

The base station can utilize a time tracking loop to track a timing advance value for each mobile communication device camped to the base station. The timing advance value may be expressed as integers, e.g., between 0-63, each integer corresponding to a time unit, e.g., about one-half microsecond (0.5 μ s). Thus, a timing advance value of 2 may indicate that the mobile communication device should transmit uplink communications approximately one microsecond before the device's allocated time slot at the base station (i.e., advance the uplink communication time), while a timing advance value of-2 may indicate that the mobile communication device should transmit uplink communications approximately one microsecond after the device's allocated time slot at the base station (i.e., delay the uplink communication time).

The base station may recalculate the uplink timing between the base station and the mobile communication device periodically or aperiodically. For example, if the base station determines that the mobile communication device has moved toward or away from the base station (e.g., the device is in a vehicle that is driving away from the base station), the base station may generate a timing advance adjustment value. The timing advance adjustment value adjusts a previous timing advance value on the mobile communication device based on a change in uplink timing between the base station and the mobile communication device. That is, the timing advance adjustment value is relative to the last determined timing advance value on the mobile communication device. For example, if the timing advance value of the mobile communication device is currently 2 and the mobile communication device has left the base station since the last time the timing advance was determined, the timing advance adjustment value generated by the base station may be 1. The mobile communication device receives the timing advance adjustment value and adjusts the previous timing advance value 2, producing a new timing advance value 3. On the other hand, if the mobile communication device has moved closer to the base station, the new advance timing value may be-1. The mobile communication device receives the timing advance adjustment value and adjusts the previous timing advance value 2, producing a new timing advance value 1. The base station sends the timing advance adjustment value to the mobile communication device, which adjusts the timing advance value stored on the mobile communication device accordingly.

Sometimes, the base station may experience an error in determining the timing advance adjustment value (e.g., a change in distance between the base station and the mobile communication device since the last determination). This may occur when the subscribed uplink transmission interval is within a certain range, which may lead to problems with the connected state reception mode on the network. Tune away may also result in errors in timing advance adjustment values. For example, during tune away, the active subscription does not communicate with the associated network of the active subscription. After tune away, the base station may be in error in determining the location of the mobile communication device, and thus may generate an erroneous timing advance adjustment value. For example, the base station may generate the timing advance adjustment value 20 after the tune away, which may mean that the mobile communication device has moved many kilometers during the duration of the tune away (on the order of milliseconds). Such timing advance adjustment values are obviously erroneous.

If such an error value is sent to the mobile communication device, and the mobile communication device adjusts the stored timing advance value accordingly, communications (i.e., uplink transmissions) with the base station may not arrive at the allocated time slot and may collide with another device-to-base station transmission. When this occurs, the uplink connection between the mobile communication device and the base station may be dropped. Reestablishing the connection and determining the correct timing advance value may take a relatively long time for the mobile communication device and the base station to complete. The network base station may also increase the redundancy of the modulation and coding scheme used for the mobile communication device, resulting in a reduction in throughput even after the uplink connection is restored.

To overcome this problem, various examples include a method implemented with a processor of a mobile communication device for initiating a timing advance protection window on the mobile communication device. The mobile communication device may initiate the timing advance protection window in two situations. In a first scenario, the mobile communication device can initiate a timing advance protection window when a tune away occurs from an active subscription (i.e., a subscription that receives a timing advance adjustment value) to support another subscription. In this case, the timing advance protection window starts at the beginning of the tune away. In a second case, the mobile communication device may initiate a timing advance protection window when it is determined that the subscribed uplink transmission interval is within a predetermined range of subframe values. The mobile communication device may periodically calculate an uplink transmission interval and trigger a timing advance protection window when the uplink transmission interval falls within a predetermined range of subframe values.

During the timing advance protection window, the device processor can determine an uplink transmission interval for a first subscription of the mobile communication device and determine an adjustment threshold based on the uplink transmission interval and an estimated velocity of the mobile communication device. The device processor may increment a timing advance adjustment counter by a timing advance adjustment value received from the first network. The device processor may determine whether an absolute value of the timing advance adjustment counter exceeds an adjustment threshold and ignore the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold. The device processor may adjust a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that an absolute value of the timing advance adjustment counter does not exceed an adjustment threshold.

The timing advance protection window may terminate after a certain period of time, for example after a period of time equal to the sum of the inactivity timer of the first subscription and the time of the short discontinuous reception cycle. In some cases, the timing advance protection window may terminate before the expiration of the time period if the first subscription has received a predetermined response pattern from the first network in response to a transmission (e.g., a number of consecutive acknowledgements) sent from the first subscription to the first network. The time period may be extended by a certain amount if the timing advance protection window is triggered by tune away and the uplink transmission interval is within a predetermined range. If the first subscription is capable of carrier aggregation, a timing advance protection window may be applied to each of one or more timing advance groups, where each timing advance group includes one or more component carriers that share the same timing advance value.

Various examples may be implemented within various communication systems 100, such as at least two mobile telephone networks, an example of which is shown in fig. 1. The first mobile network 102 and the second mobile network 104 typically each include a plurality of cellular base stations (e.g., a first base station 130 and a second base station 140). The first multi-SIM communication device 110 may communicate with the first mobile network 102 through a cellular connection 132 to the first base station 130. The first multi-SIM communication device 110 may also communicate with the second mobile network 104 through a cellular connection 142 to the second base station 140. The first base station 130 may communicate with the first mobile network 102 over a wired connection 134. The second base station 140 may communicate with the second mobile network 104 through a wired connection 144.

The second multi-SIM communication device 120 may similarly communicate with the first mobile network 102 through a cellular connection 132 to the first base station 130. The second multi-SIM communication device 120 may also communicate with the second mobile network 104 through a cellular connection 142 to the second base station 140. Cellular connection 132 and cellular connection 142 may be made over a two-way wireless communication link, such as 4G LTE, 3G, CDMA, TDMA, WCDMA, GSM, and other mobile telephone communication technologies.

The multi-SIM communication devices 110, 120 may be at different distances from the first base station 130 and the second base station 140. For example, the multi-SIM communication device 110 may be closer to the first base station 130 than the multi-SIM communication device 120. The first base station 130 may maintain a time tracking loop for the multi-SIM communication device 110, 120 to track the distance between the multi-SIM communication device 110, 120 and the first base station 130. The time tracking loop may be used to generate a timing advance adjustment value for the multi-SIM communication device 110, 120 that depends on a change in the distance between the first base station 130 and the multi-SIM communication device 110, 120. The multi-SIM communication devices 110, 120 may each maintain a timing advance value that is adjusted by the timing advance adjustment value calculated by the first base station 130 and sent to each of the multi-SIM communication devices 110, 120. Similar to the first base station 130, the second base station 140 may also maintain a time tracking loop for the multi-SIM communication device 110, 120.

Although the multi-SIM communication device 110, 120 is shown connected to the first mobile network 102 and optionally to the second mobile network 104, in some examples (not shown), the multi-SIM communication device 110, 120 may include two or more subscriptions to two or more mobile networks and may connect to those subscriptions in a manner similar to that described above.

In some examples, the first multi-SIM communication device 110 may optionally establish a wireless connection 152 with a peripheral device 150 used in conjunction with the first multi-SIM communication device 110. For example, the first multi-SIM communication device 110 may communicate with the bluetooth enabled personal computing devices (e.g., "smart watch") via bluetooth @links. In some examples, the first multi-SIM communication device 110 may optionally establish a wireless connection 162 with the wireless access point 160, such as over a Wi-Fi connection. The wireless access point 160 may be configured to connect to the internet 164 or another network through a wired connection 166.

Although not shown, the second multi-SIM communication device 120 may similarly be configured to connect with the peripheral device 150 and/or the wireless access point 160 via a wireless link.

Fig. 2 is a functional block diagram of a multi-SIM communication device 200 suitable for implementing various examples. Referring to fig. 1-2, the multi-SIM communication device 200 may be similar to one or more of the multi-SIM communication devices 110, 120 as described. The multi-SIM communication device 200 may include a first SIM interface 202a that may receive a first identity module SIM-1204 a associated with a first subscription. The multi-SIM communication device 200 may also optionally include a second SIM interface 202b, which may receive an optional second identity module SIM-2204 b associated with a second subscription.

The SIM in various examples may be a Universal Integrated Circuit Card (UICC) configured with SIM and/or universal SIM applications to enable access to, for example, GSM and/or UMTS networks. The UICC may also provide storage for phone books and other applications. Alternatively, in a CDMA network, the SIM may be a UICC removable user identity module (R-UIM) or a CDMA Subscriber Identity Module (CSIM) on a card. The SIM card may have a CPU, ROM, RAM, EEPROM, and I/O circuitry.

The SIM used in various examples may contain user account information, International Mobile Subscriber Identity (IMSI), SIM Application Toolkit (SAT) command set, and storage space for phonebook contacts. The SIM card may also store a home identifier (e.g., a system identification number (SID)/network identification Number (NID) pair, a home plmn (hplmn) code, etc.) to indicate the SIM card network operator provider. An Integrated Circuit Card Identity (ICCID) SIM serial number may be printed on the SIM card for identification. However, the SIM may be implemented within a portion of the memory of the multi-SIM communication device 200 (e.g., in the memory 214), and thus need not be a separate or removable circuit, chip, or card.

The multi-SIM communication device 200 can include at least one controller, such as a general purpose processor 206, which can be coupled to a coder/decoder (CODEC) 208. The CODEC 208 may in turn be coupled to a speaker 210. The general purpose processor 206 may also be coupled to a memory 214. The memory 214 may be a non-transitory computer-readable storage medium that stores processor-executable instructions. For example, the instructions may include routing communication data related to the first or second subscription through the corresponding baseband-RF resource.

The memory 214 may store an Operating System (OS), as well as user application software and executable instructions. The memory 214 may store timing advance values used to determine timing offsets for communicating with network base stations.

The general purpose processor 206 and the memory 214 may each be coupled to at least one baseband modem processor 216. Each SIM and/or RAT in the multi-SIM communication device 200 (e.g., SIM-1204 a and/or SIM-2204 b) may be associated with baseband-RF resources. The baseband-RF resources may include a baseband modem processor 216, which may perform baseband/modem functions for a communication/control RAT with the RAT, and may include one or more amplifiers and radio units, which are generally referred to herein as RF resources (e.g., RF resources 218). In some examples, the baseband-RF resources may share a baseband modem processor 216 (i.e., a single device for performing baseband/modem functions for all RATs on the multi-SIM communication device 200). In other examples, each baseband-RF resource may include a physically or logically separate baseband processor (e.g., BB1, BB 2).

The RF resource 218 may be a transceiver for performing transmit/receive functions for each SIM/RAT on the multi-SIM communication device 200. RF resource 218 may include separate transmit and receive circuits or may include a transceiver that combines transmitter and receiver functionality. In some examples, RF resource 218 may include multiple receive circuits. RF resource 218 may be coupled to a wireless antenna (e.g., wireless antenna 220). RF resource 218 may also be coupled to baseband modem processor 216.

In some examples, the general purpose processor 206, the memory 214, the baseband processor 216, and the RF resources 218 may be included in the multi-SIM communication device 200 as a system-on-chip 250. In some examples, the first and second SIMs 204a, 204b and their corresponding interfaces 202a, 202b may be external to the system-on-chip 250. In addition, various input devices and output devices may be coupled to components on the system-on-chip 250, such as interfaces or controllers. Example user input components suitable for use with the multi-SIM communication device 200 may include, but are not limited to, a keypad 224, a touch screen display 226, and a microphone 212.

In some examples, keypad 224, touch screen display 226, microphone 212, or a combination thereof may perform the function of receiving a request to initiate an outgoing call. For example, the touch screen display 226 may receive a selection of a contact from a contact list or receive a telephone number. In another example, either or both of the touch screen display 226 and the microphone 212 may perform the function of receiving a request to initiate an outgoing call. For example, the touch screen display 226 may receive a user selection of a contact from a contact list or receive a telephone number. As another example, the request to initiate the outgoing call may be in the form of a voice command received via the microphone 212. Interfaces may be provided between the various software modules and functions in the multi-SIM communication device 200 to enable communication therebetween, as is known in the art.

By working together, the two SIMs 204a, 204b, baseband processors BB1, BB2, RF resources 218, and wireless antenna 220 may constitute two or more Radio Access Technologies (RATs). For example, the multi-SIM communication device 200 may be a communication device that includes a SIM, a baseband processor, and RF resources configured to support two different RATs, e.g., LTE and GSM. More RATs may be supported on the multi-SIM communication device 200 by adding more SIM cards, SIM interfaces, RF resources, and antennas for connecting to additional mobile networks.

In some examples (not shown), the multi-SIM communication device 200 can additionally include additional SIM cards, SIM interfaces, multiple RF resources associated with the additional SIM cards, and additional antennas to support subscription communications with other mobile networks, among other things.

Fig. 3 illustrates the operation of timing advance for a network base station, such as an enodeb station of an LTE network. Referring to fig. 1-3, a timing diagram 300 illustrates uplink transmissions for a first mobile communication device 302 (e.g., 110, 200), labeled UE1, and a second mobile communication device 304, labeled UE 2. The mobile communication devices 302 and 304 communicate with a base station 306 (e.g., 130, 140 in fig. 1) labeled enodeb. In the illustrated example, the mobile communication devices 302 and 304 are at different distances from the base station 306. For example, the first mobile communication device 302 can be farther from the base station 306 than the second mobile communication device 304. The base station 306 allocates a particular time slot to receive the transmission from the mobile communication devices 302, 304, the particular time slot being illustrated by the vertical dashed line in the timing diagram 300. The base station 306 can have a time tracking loop that generates a timing advance adjustment value for the mobile communication devices 302, 304.

The second mobile communication device 304 can transmit the data blocks 310a, 310b with the timing advance value 314. The timing advance value 314 may represent a time offset in which the second mobile communication device 304 should transmit the data block 310a, 310b such that the data block 310a, 310b arrives at the base station 306 during the allocated time slot for the second mobile communication device 304. Likewise, the first mobile communication device 302 can transmit the data blocks 308a, 308b with the timing advance value 312. The advance value 312 may represent a time offset in which the first mobile communication device 302 should transmit the data block 308a, 308b such that the data block 308a, 308b arrives at the base station 306 during the allocated time slot for the first mobile communication device 302. When the uplink connection is first established, the timing advance values 312, 314 may initially be zero, but are periodically adjusted by the base station 306. In the example shown in timing diagram 300, timing advance value 312 is greater than timing advance value 314. This may indicate that the first mobile communication device 302 is farther from the base station 306 than the second mobile communication device 304. The difference in distance means that the data blocks 308a, 308b take longer to reach the base station 306 than the data blocks 310a, 310 b. Therefore, the timing advance value 312 is larger in order to account for the additional time for the data blocks 308a, 308b to arrive at the base station 306. Other factors that may affect uplink timing include changes in the propagation environment, oscillation drift in the mobile communication device, and doppler effects that are independent of range changes. The timing advance values 312, 314 may be stored on the mobile communication devices 302, 304, respectively.

The base station 306 can store time tracking loops for each of the mobile communication devices 302, 304 and other devices residing on the base station 306. The time tracking loop can calculate a timing advance adjustment value that is then transmitted to the mobile device. The timing advance value may be expressed as an integer, such as an integer between 0-63. Each integer may correspond to a time unit, for example, approximately one-half microsecond (0.5 μ s).

The base station 306 can periodically recalculate the uplink timing between the base station 306 and the mobile communication devices 302, 304. The base station 306 can determine a timing advance adjustment value for the mobile communication devices 302, 304 based on the uplink timing calculation. The base station 306 can generate a timing advance adjustment value for each of the mobile communication devices 302, 304. The timing advance adjustment value adjusts the timing advance value for the mobile communication devices 302, 304 based on changes in distance or other factors. The base station 306 transmits the timing advance adjustment value to each of the mobile communication devices 302, 304, which can result in a change in the timing advance value stored on each of the mobile communication devices 302, 304.

Sometimes, the base station may make an error in determining the timing advance adjustment value, which may result in transmission collisions between mobile communication devices transmitting to the base station. Fig. 4 shows an example of an error of the determined timing advance adjustment value. Referring to fig. 1-4, a timing diagram 400 illustrates uplink transmissions for a first mobile communication device 402 (e.g., 110, 200), labeled UE1, and a second mobile communication device 404, labeled UE 2. The mobile communication devices 402 and 404 communicate with a base station 406 (e.g., 130, 140) labeled enodeb. The mobile communication devices 402 and 404 are at different distances from the base station 406. For example, the first mobile communication device 402 may be further from the base station 406 than the second mobile communication device 404. The base station 406 allocates a particular time slot to receive a transmission from the mobile communication device 402, 404, the particular time slot being illustrated by the vertical dashed line in the timing diagram 400. The base station 406 can have a time tracking loop that tracks the timing advance value for the mobile communication devices 402, 404.

The second mobile communication device 404 can transmit the data block 410a, 410b including the timing advance value 414. The timing advance value 414 may represent a time offset in which the second mobile communication device 404 should transmit the data blocks 410a, 410b such that the data blocks 410a, 410b arrive at the base station 406 during the allocated time slots for the second mobile communication device 404. The first mobile communication device 402 may be scheduled to transmit a data block 408a with a timing advance value 412. However, in the example shown, at this point the first mobile communication device 402 performs a tune away from an active subscription for communicating with the base station 406 to another subscription for communicating with another network. For example, the first mobile communication device 402 can tune away from an LTE subscription to communicate with the base station 406 to a GSM subscription to communicate with another base station. As a result, data block 408a is not sent to base station 406.

Once the tune away is complete, the base station 406 can calculate an erroneous timing advance adjustment value for the first mobile communication device 402 that does not correspond to the actual change in uplink timing. For example, while the first mobile communication device 402 may not have moved before tuning away, the base station may calculate a positive timing advance adjustment value indicating that the first mobile communication device 402 has moved away from the base station 406. The base station 406 may transmit the wrong timing advance adjustment value to the first mobile communication device 402. The mobile communication device adjusts the timing advance value 412 by the timing advance adjustment value to produce a new timing advance value 416. In the example shown in timing diagram 400, although timing advance value 416 is greater than timing advance value 412, timing advance value 416 may also be smaller depending on the timing advance adjustment value calculated by base station 406.

If the first mobile communication device 402 sends the data block 408b to the base station 406 using the timing advance value 416 as shown, the data block 408b arrives at the base station 406 before the end of the transmission of the data block 410b by the second mobile communication device 404. If this occurs, the base station 406 may ignore the data block 408b because the data block 408b does not arrive at the allocated time slot. This results in a loss of the uplink connection between the first mobile communication device 402 and the base station 406. Reestablishing the uplink connection may take a longer time and the base station may penalize the first mobile communication device 402 by reducing the efficacy of the modulation and coding scheme used to communicate with the first mobile communication device 402.

Various examples disclosed herein provide a timing advance protection window that can be initiated to monitor and prevent erroneous timing advance adjustment values. During the timing advance protection window, the mobile communication device can determine whether an absolute value of a cumulative sum of timing advance adjustment values received from the network during the protection window exceeds an adjustment threshold. If the mobile communication device determines that the absolute value of the cumulative sum of timing advance adjustment values exceeds the adjustment threshold, the mobile communication device can ignore the timing advance adjustment values until the absolute value of the cumulative sum is less than the adjustment threshold or the timing advance protection window ends. The mobile communication device may apply the timing advance adjustment value to the timing advance value stored by the mobile communication device as long as the cumulative timing advance adjustment value received from the network is less than the adjustment threshold. The calculation of the cumulative sum allows the mobile communication device to detect errors in a larger single value of the timing advance adjustment value, as well as smaller cumulative errors from successive timing advance adjustment values. The cumulative sum of the timing advance adjustment values may be represented by a timing advance adjustment counter.

The adjustment threshold may be calculated each time a new timing advance protection window is initiated. The adjustment threshold may be based on a subscribed uplink transmission interval. Uplink transmission interval Δ T_UL-TxMay be determined as the number of subframes between two transmission packets sent by the subscription. For example, if the uplink transmission interval is less than or equal to 5000 subframes (i.e., Δ Τ)_UL-Tx5000 ≦ 5000), the adjustment threshold may be set to 3, while if the uplink transmission interval is between 5000 and 8000 subframes (i.e., 5000 and 8000 subframes)<ΔT_UL-Tx8000), the adjustment threshold may be set to 4. This takes into account the fact that: as the time between transmissions increases, the timing advance adjustment value may be larger before the adjustment is likely to be erroneous because the mobile communication device has more time to move toward or away from the base station.

In some cases, the mobile communication device may impose a limit on when to apply the adjustment threshold. The mobile communication device may not apply the adjustment threshold if the uplink transmission interval exceeds a predetermined upper limit, in which case the mobile communication device may accept and apply the timing advance adjustment value received from the network. The predetermined upper limit for when to apply the adjustment threshold may be an uplink transmission interval that is long enough that a larger timing advance adjustment value is valid. In a non-limiting example, the predetermined upper limit for when to apply the adjustment threshold may be determined to be 10240 subframes (equivalent to 10.24 seconds).

The adjustment threshold may also be based on an estimated speed of the mobile communication device. The estimated velocity of the mobile communication device may be calculated as

Wherein

Is an estimated velocity of the mobile communication device, dopplersread is a doppler spread value obtained from a doppler estimation unit in the mobile communication device, CarrierFreq is a center frequency used by a network base station to communicate with a subscription, and

is the speed of light.

Can estimate the speed

Compared to a threshold value representing a high travel speed (e.g., the maximum speed of a high speed train in the country or region of service). For example, the threshold may be 170 kilometers per hour (106 miles per hour). If the estimated speed equals or exceeds the threshold, a high speed flag in memory may be set indicating that a higher adjustment threshold may be used. For example, if the uplink transmission interval is less than or equal to 5000 subframes (i.e., Δ Τ)_UL-Tx≦ 5,000) and the high speed flag is not set, the adjustment threshold may be set to 3. However, if the high speed flag is set, the adjustment threshold may be set to 5 with the same uplink transmission interval. Thus, the high speed flag may enable the mobile communication device to consider the following: the device is traveling at a high rate and thus a larger timing advance adjustment value may be effective. In an example, the mobile communication device can store a lookup table that correlates combinations of uplink transmission intervals and high speed flag values with adjustment thresholds.

The timing advance protection window may be initiated when the subscribed uplink transmission interval (i.e., the time between uplink transmissions) is within a predetermined range. This range may take into account timing advances in which the uplink transmission interval is long enough that the network may generate errorsA period of a pre-adjustment value (e.g., an uplink transmission interval that triggers a connection status reception mode on the network). For example, the uplink transmission interval may be between an upper limit and a lower limit (i.e., M ≦ Δ T)_UL-TxN) or less, initiating a timing advance protection window. In a non-limiting example, the lower limit M may be set to 10 subframes and the upper limit N may be set to 10240 subframes.

The timing advance guard window may last for a predetermined period of time. For example, the duration of the timing advance protection window may be equal to the sum of the inactivity timer of the subscription and the period of the short discontinuous reception cycle. The time of inactivity and the period of the short discontinuous reception cycle are variables that may be maintained by the network and obtained by the mobile communication device from the network when the timing advance protection window is initiated.

Under certain conditions, the timing advance protection window may be terminated by the mobile communication device earlier than a usual time period. For example, the mobile communication device may terminate the timing advance protection window if the subscription receives a predetermined response pattern from the network in response to the uplink transmission. A non-limiting example of a predetermined response pattern may be a threshold number of consecutive Acknowledgement (ACK) messages (e.g., four consecutive ACKs) received from the network. This threshold takes into account the fact that: successful receipt by the network of all transmissions sent by the mobile communication device for the subscription indicates that there is no timing advance value mismatch between the subscription and the network. When the network is utilizing adaptive retransmission, the mobile communication device can treat receipt of an ACK message without a New Data Indicator (NDI) bit toggled as receipt of a non-acknowledgement (NAK) message. Other examples of predetermined response patterns may be a threshold number of non-acknowledgements (NAKs), or a particular pattern or percentage of ACKs and/or NAKs and/or other messages received from the network.

If a tune away occurs from an active subscription to another subscription, the timing-advanced protection window may also be initiated or restarted if another protection window is already activated when the tune away occurs. The duration of the timing advance guard window triggered by tune away may be a set number of subframes (e.g., 10 subframes). However, if subscribed toIs within a predetermined range (e.g., 10 ≦ Δ T)_UL-Tx10240), the duration of the timing advance protection window may be extended by an additional period of time, e.g., by the sum of the period of the short discontinuous reception cycle and the inactivity timer of the subscription. If another tune away occurs during the time period of the current timing advance protection window, the mobile communication device may restart the timing advance protection window triggered by the tune away. When restarted, the adjustment threshold, the uplink transmission interval, the inactivity timer value, and the period of the short discontinuous reception cycle may be recalculated and utilized in a new timing advance protection window.

If the subscription is capable of carrier aggregation (e.g., LTE subscription), the mobile communication device may group the subscribed component carriers into one or more timing adjustment groups. For example, the primary component carrier may be in a first timing adjustment group and the one or more secondary component carriers may be in a second timing adjustment group. There may be one timing adjustment group per frequency band utilized by the network. Each timing adjustment group may share the same timing advance value and adjustment value received from the network. Thus, the mobile communication device can implement separate timing advance protection windows for each timing adjustment group.

Fig. 5A-5B illustrate timing advance protection windows with advance termination according to various examples. Referring to fig. 1-5B, fig. 5A shows a timing diagram 500a with a timing advance protection window that is prematurely terminated due to successful reception by the network, while fig. 5B shows a timing diagram 500B with a timing advance protection window that is prematurely terminated due to tune away. In both timing diagrams 500a, 500B, a subscription in a mobile communication device (labeled "UE") may communicate with a network base station (labeled "enodeb"). The mobile communication device can maintain a timing advance value with respect to a network associated with the subscription. The network may occasionally send a timing advance adjustment value to the subscription, and the mobile communication device may adjust the timing advance value with the timing advance adjustment value.

In the timing diagram 500a shown in fig. 5A, the mobile communication device can send data packets for a subscription to the network in an uplink transmission 510, and if the network successfully receives and decodes the packet, the network can respond with an acknowledgement 512. The mobile communication device can perform data packet transmission for the subscription according to the uplink transmission interval 502. The uplink transmission interval 502 can vary depending on the activity of the user of the mobile communication device (e.g., web browsing, chat, idle, etc.) and other factors.

The mobile communication device can determine whether the uplink transmission interval 502 is within a predetermined range (e.g., between 10 and 10240 subframes). In response to determining that the uplink transmission interval 502 is within the predetermined range, the mobile communication device can initiate a timing advance protection window for the time period 504. The time period 504 may be calculated by the mobile communication device as the sum of the inactivity timer and the period of the short discontinuous reception cycle for the subscription. During the timing advance protection window, the mobile communication device can use the timing advance adjustment counter to calculate the cumulative sum of the timing advance adjustment values received from the network. In response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold, the mobile communication device can ignore the timing advance adjustment value until the absolute value of the timing advance adjustment counter falls below the adjustment threshold or the time period 504 ends. The adjustment threshold may be based on the uplink transmission interval 502 and the estimated speed of the mobile communication device.

During time period 504, the mobile communication device may send additional data packets for the subscription to the network in uplink transmission 514, and the network may respond with a response message 516. In response to the mobile communication device receiving a predetermined response pattern (e.g., a threshold number of consecutive ACKs) for the subscription from the network in response message 516, the mobile communication device can prematurely terminate the timing advance protection window after a time period 506 when the predetermined response pattern has been detected. In response to determining that the response message 516 does not include the predetermined response pattern, the mobile communication device can maintain a timing advance protection window until the end of the time period 504.

Timing diagram 500B in fig. 5B shows that the subscription may start sending uplink transmissions 514 but is interrupted by tune away 518. During tune away 518, the shared RF resources of the mobile communication device may tune from an active subscription to an idle subscription so that the idle subscription may perform idle mode operation and receive paging notifications. When the tune away 518 begins, the mobile communication device may restart the timing advance protection window within time period 508. The time period 508 may initially last a set number of subframes (e.g., ten subframes). However, if the uplink transmission interval 502 is within a predetermined range (e.g., between 10 and 10240 subframes), the mobile communication device may extend the time period 508 of the restarted timing advance protection window by an additional time period, such as by the sum of the periods of the subscribed inactivity timer and the short discontinuous reception cycle. When restarted, the mobile communication device may recalculate and use the adjustment threshold, the uplink transmission interval 502, the inactivity timer value, and the period of the short discontinuous reception cycle in the new timing advance protection window.

Fig. 6 includes a timing diagram 600 illustrating a tune-away triggered timing advance protection window, according to various examples. Referring to fig. 1-6, a subscription in a mobile communication device (labeled "UE") may communicate with a network base station (labeled "enodeb"). The mobile communication device can maintain a timing advance value with respect to a network associated with the subscription. The network may occasionally send a timing advance adjustment value to the mobile communication device for a subscription, and the mobile communication device may adjust the timing advance value with the timing advance adjustment value.

Timing diagram 600 shows the mobile communication device performing tune away 608 at subframe k during which the mobile communication device's shared RF resources tune from an active subscription to an idle subscription so that the idle subscription can perform idle mode operation and receive paging notifications. When a tune away 608 occurs, the mobile communication device may initiate a timing advance protection window within time period 602. The time period 602 may have a predetermined duration (e.g., N subframes). During the timing advance protection window, the mobile communication device can use the timing advance adjustment counter to calculate the cumulative sum of the timing advance adjustment values received from the network. In response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold, the mobile communication device can ignore the timing advance adjustment value until the absolute value of the timing advance adjustment counter is less than the adjustment threshold or the time period 602 ends. The adjustment threshold may be based on the subscribed uplink transmission interval and the estimated speed of the mobile communication device.

During time period 602, the mobile communication device can determine whether the subscribed uplink transmission interval is within a predetermined range (e.g., between 10 and 10240 subframes). In response to determining that the uplink transmission interval is within the predetermined range, the mobile communication device can extend the timing advance protection window such that the window lasts for the time period 604. Is represented as N_extMay be the period 602 plus the sum of the subscribed inactivity timer and the period of the short discontinuous reception cycle.

Timing diagram 600 shows how another tune away 610 may occur during time period 604. When the tune away 610 begins, the mobile communication device may restart the timing advance protection window for a time period 606 (e.g., N subframes, plus an additional amount if the uplink transmission interval is within a predetermined range). When restarted, the adjustment threshold, the uplink transmission interval, the inactivity timer value, and the period of short discontinuous reception cycles may be recalculated by the mobile communication device and used in a new timing advance protection window.

Fig. 7 illustrates a methodology 700 for initiating a timing advance protection window on a mobile communication device to avoid problems that may occur when a base station transmits an erroneous timing advance adjustment value, in accordance with various examples. Referring to fig. 1-7, the method 700 may be implemented with a processor (e.g., general processor 206, baseband modem processor 216, separate controller, etc.) of a mobile communication device, such as the multi-SIM communication devices 110, 120, and 200. The mobile communication device may have one RF resource shared by a first subscription and a second subscription (e.g., MSMS communication device). The first subscription may maintain a timing advance value from the first network (e.g., in a protocol stack of the mobile communication device). The first network may occasionally send a timing advance adjustment value to the mobile communication device for the first subscription.

The method 700 is extendable to a plurality of component carriers of a subscription in a carrier aggregation capable mobile communication device. The subscribed component carriers may be divided into a plurality of timing adjustment groups, where each timing adjustment group shares the same timing advance value and the same frequency band. Thus, the method 700 can be applied independently to each timing adjustment group of subscriptions maintained in the mobile communication device.

In block 702, the processor may determine an uplink transmission interval for a first subscription. The uplink transmission interval may be the number of subframes between consecutive uplink transmissions sent by the subscription. For example, if the first subscription is scheduled to send uplink packets every 10 subframes, the uplink transmission interval will be 10. The processor may periodically determine an uplink transmission interval when the first subscription is active on the mobile communication device (i.e., using the shared RF resource).

In determination block 704, the processor may determine whether the uplink transmission interval of the first subscription is within a predetermined range of values. The predetermined range may take into account a period in which the uplink transmission interval is long enough that the network may generate erroneous timing advance adjustment values. For example, the timing advance protection window may be initiated when the uplink transmission interval is between an upper bound N and a lower bound M. In a non-limiting example, the lower limit M may be set to 10 subframes and the upper limit N may be set to 10240 subframes.

In response to determining that the uplink transmission interval is not within the predetermined range (i.e., determination block 704 = "no"), the processor may adjust the timing advance value maintained by the first subscription in block 706 by a timing advance adjustment value received from the first network. In other words, the processor may apply the received timing advance adjustment value upon determining that the uplink transmission interval is outside a range in which the received timing advance adjustment value may be erroneous. The processor may periodically re-determine whether the uplink transmission interval of the first subscription is within a predetermined range (i.e., return to operations in block 702).

In response to determining that the uplink transmission interval is within the predetermined range (i.e., determination block 704 = "yes"), the processor may initiate a timing advance protection window by determining an adjustment threshold in block 708. The adjustment threshold may be based on a subscribed uplink transmission interval. For example, if the uplink transmission interval is less than or equal to 5000 subframes, the processor may set the adjustment threshold to 3, and if the uplink transmission interval is between 5000 and 8000 subframes, the processor may set the adjustment threshold to 4. These adjustments of the uplink transmissions may enable the mobile communication device to adapt to larger timing advance adjustment values as the time between transmissions increases, as the mobile communication device has more time to move toward or away from the base station.

The adjustment threshold may also be based on an estimated speed of the mobile communication device. The estimated velocity of the mobile communication device may be calculated as

Wherein

Is an estimated velocity of the mobile communication device, dopplersread is a doppler spread value obtained from a doppler estimation unit in the mobile communication device, CarrierFreq is a center frequency used by the first network base station to communicate with the first subscription, and

is the speed of light.

As part of the operations in block 708, the estimated speed may be compared to a threshold value representing a high travel speed (e.g., to account for when the user is traveling on a high speed train). For example, the threshold may be 170 km/h. In response to determining that the estimated speed equals or exceeds the threshold, the processor may set a high speed flag in the memory indicating that a higher adjustment threshold may be used. For example, if the uplink transmission interval is less than or equal to 5000 subframes and the high speed flag is not set, the processor may set the adjustment threshold to 3. However, if the high speed flag is set, the processor may instead set the adjustment threshold to 5. Thus, a high speed flag may be set in memory to account for when the mobile communication device is traveling quickly, and thus larger timing advance adjustment values may be effective. The processor may store a lookup table that associates uplink transmission interval ranges and high speed flag values with adjustment thresholds.

In block 710, the processor may increment a timing advance adjustment counter with a timing advance adjustment value received from the first network. The processor may set the timing advance adjustment counter to zero when the timing advance protection window is initiated or restarted. When the first subscription receives a timing advance adjustment value from the first network, the processor may increment a timing advance adjustment counter by each received value. For example, in response to the first subscription initially receiving a timing advance adjustment value of 2, the processor may increment a timing advance adjustment counter by 2. If the next timing advance adjustment value received is-1, the processor may set the timing advance adjustment counter to 1 (i.e., 2+ (-1) = 1).

In determination block 712, the processor may determine whether the absolute value of the timing advance adjustment counter exceeds an adjustment threshold.

In response to determining that the absolute value of the timing advance adjustment counter does not exceed the adjustment threshold (i.e., determination block 712 = "no"), the processor may adjust the timing advance value maintained by the first subscription by the timing advance adjustment value received from the first network in block 716. In other words, the received timing advance adjustment value is likely correct and may be applied when the absolute value of the timing advance adjustment counter is less than a threshold.

In response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold (i.e., determination block 712 = "yes"), the processor may ignore the timing advance adjustment value received from the first network in block 714. In other words, the received timing advance adjustment value is likely to be erroneous and should not be used when the absolute value of the timing advance adjustment counter exceeds a threshold.

After applying the received timing advance adjustment value in block 716 or ignoring the adjustment in block 714, the processor may determine whether tune away has been initiated in determination block 718. For example, the mobile communication device may periodically tune the shared RF resource from a first subscription to a second subscription so that the second subscription may perform idle mode operation and check for paging notifications.

In response to determining that a tune away has been initiated (i.e., determination block 718 = "yes"), the processor may initiate a new timing advance protection window within a particular time period when the tune away begins in block 720. The timing advance protection window triggered by tune away is discussed in more detail with reference to method 800 of fig. 8.

In response to determining that tune away has not been initiated (i.e., determination block 718 = "no"), the processor may determine whether the first subscription has received a predetermined response pattern from the first network in determination block 722. For example, the first subscription may be sending a data packet during a timing advance protection window, and the first network may respond with an Acknowledgement (ACK) if the packet is successfully received, or a non-acknowledgement (NAK) if the packet is not successfully received. In the case when the network is utilizing adaptive retransmission, the processor may treat the response as a NAK if an ACK is received but the New Data Indicator (NDI) bit is not toggled. In some non-limiting examples, the predetermined response pattern may be a threshold number of consecutive acknowledgements (e.g., four ACKs), a threshold number of consecutive NAKs, or a particular pattern or percentage of ACKs and/or NAKs and/or other response messages. If the first subscription is capable of carrier aggregation, the processor may treat the timing advance group as a received ACK if all component carriers have received ACKs. The processor may treat the set of timing advances as a received NAK if a NAK has been received for at least one component carrier.

In response to determining that the first subscription has received the predetermined response pattern from the first network (i.e., determination block 722 = "yes"), the processor may terminate the timing advance protection window and resume determining the uplink transmission interval in block 702. In other words, successful receipt of all or most of the packets sent by the first subscription indicates that there are few or no errors in the timing advance adjustment value. Thus, when the first network indicates successful reception of a transmitted packet, the processor may terminate the current timing advance protection window and begin a new timing advance protection window at a future time (e.g., when a future uplink transmission interval falls within a predetermined range).

In response to determining that the first subscription has not received the predetermined response pattern from the first network (i.e., determination block 722 = "no"), the processor may determine whether the timing advance protection window time period has expired in determination block 724. When the processor determines that the uplink transmission interval is within the predetermined range (i.e., after the operations in determination block 704), the processor may start the timing advance guard window time. In some examples, the timing advance protection window period may be calculated as the sum of the subscribed inactivity timer and the period of the short discontinuous reception cycle. The values of the inactivity timer and the period of the short discontinuous reception cycle may be obtained by the processor from the first network.

In response to determining that the timing advance protection window time period has not expired (i.e., determination block 724 = "no"), the processor may increment a timing advance adjustment counter with the next received timing advance adjustment value in block 710. In other words, the processor may continue to receive the timing advance adjustment value from the network and compare the absolute value of the timing advance adjustment counter to the dynamic adjustment threshold when the advance protection window has not expired.

In response to determining that the timing advance protection window time period has expired (i.e., determination block 724 = "yes"), the processor may terminate the timing advance protection window and resume determining the uplink transmission interval in block 702. In other words, the processor may terminate the current timing advance protection window and start a new timing advance protection window at a future time (e.g., when a future uplink transmission interval falls within a predetermined range). In this manner, the method 700 provides adaptive monitoring and protection of timing advance adjustment values received by the subscription from the network.

Fig. 8 illustrates a methodology 800 for initiating a tune away triggered timing advance protection window on a mobile communication device to avoid problems that may occur when a base station transmits an erroneous timing advance adjustment value, in accordance with various examples. Referring to fig. 1-8, the method 800 may be implemented with a processor (e.g., general processor 206, baseband modem processor 216, separate controller, etc.) of a mobile communication device, such as the multi-SIM communication devices 110, 120, and 200. The mobile communication device may have one RF resource shared by a first subscription and a second subscription (e.g., MSMS communication device). The first subscription may maintain a timing advance value from the first network, the first network occasionally sending a timing advance adjustment value to the first subscription.

The method 800 may be extended to a subscribed plurality of component carriers supported on a carrier aggregation capable mobile communication device. The subscribed component carriers may be divided into a plurality of timing adjustment groups, where each timing adjustment group shares the same timing advance value and the same frequency band. Thus, the method 800 may be applied independently to each timing adjustment group.

In block 720, the processor may initiate a new timing advance protection window for a period of time at the beginning of the tune away. For example, the mobile communication device may periodically tune the shared RF resource from a first subscription to a second subscription so that the second subscription may perform idle mode operation and check for paging notifications. When a tune away occurs, the processor may initiate a timing advance protection window within a predetermined time period. In a non-limiting example, the predetermined period of time may be 10 or 20 subframes. If the timing advance protection window is already active when the tune away occurs, the timing advance protection window may be restarted with a duration equal to the predetermined time period.

In block 802, the processor may determine an uplink transmission interval for a first subscription. The uplink transmission interval may be the number of subframes between consecutive uplink transmissions sent by the subscription. For example, the first subscription may be scheduled to transmit uplink packets every 10 subframes, in which case the uplink transmission interval may be 10.

In block 804, the processor may determine an adjustment threshold. The adjustment threshold may be based on a subscribed uplink transmission interval. For example, if the uplink transmission interval is less than or equal to 5000 subframes, the processor may set the adjustment threshold to 3, and if the uplink transmission interval is between 5000 and 8000 subframes, the processor may set the adjustment threshold to 4. As discussed above, changing the adjustment threshold enables the mobile communication device to accept larger timing advance adjustment values as the time between transmissions increases because the mobile communication device has more time to move toward or away from the base station.

The adjustment threshold determined in block 804 may also be based on an estimated velocity of the mobile communication device. The estimated velocity of the mobile communication device may be calculated as

Wherein

Is an estimated velocity of the mobile communication device, dopplersread is a doppler spread value obtained from a doppler estimation unit in the mobile communication device, CarrierFreq is a center frequency used by the first network base station to communicate with the first subscription, and

is the speed of light.

In determining the adjustment threshold in block 804, the processor may compare the estimated speed to a threshold indicative of a high travel speed (e.g., the user is traveling on a high speed train). For example, the threshold may be 170 km/h. If the estimated speed is equal to or exceeds the threshold, then as part of the operations in block 804, the processor may set a high speed flag to indicate that a higher adjustment threshold may be used. For example, if the uplink transmission interval is less than or equal to 5000 subframes and the high speed flag is not set, the processor may set the adjustment threshold to 3 in block 804. However, if the high speed flag is set, the processor may set the adjustment threshold to 5 in block 804. Thus, the high speed flag may take into account the fact that: the mobile communication device may be traveling quickly and thus a larger timing advance adjustment value may still be valid. The mobile communication device can store a lookup table that associates uplink transmission interval ranges and high speed flag values with adjustment thresholds.

In determination block 806, the processor may determine whether the uplink transmission interval of the first subscription exceeds a predetermined upper limit. The predetermined upper limit may represent an uplink transmission interval that is long enough such that a large timing advance adjustment value may not be considered erroneous. In a non-limiting example, the predetermined upper limit may be set to 10240 subframes.

In response to determining that the uplink transmission interval exceeds the predetermined upper limit (i.e., determination block 806 = "yes"), the processor may adjust the timing advance value maintained by the first subscription by the timing advance adjustment value received from the first network in block 814. In other words, the processor may accept and apply the received timing advance adjustment value when the uplink transmission interval is greater than the upper limit.

In response to determining that the uplink transmission interval does not exceed the predetermined upper limit (i.e., determination block 806 = "no"), the processor may increment a timing advance adjustment counter with a timing advance adjustment value received from the first network in block 808. The processor may set the timing advance adjustment counter to zero when the timing advance protection window is initiated or restarted. When the first subscription receives a timing advance adjustment value from the first network, the processor may increment a timing advance adjustment counter by each received value. For example, if the first subscription initially receives a timing advance adjustment value of 2, the processor may increment a timing advance adjustment counter to 2. If the next timing advance adjustment value received is-1, the processor may set the timing advance adjustment counter to 1 (i.e., 2+ (-1) = 1).

In determination block 810, the processor may determine whether the absolute value of the timing advance adjustment counter exceeds an adjustment threshold. In response to determining that the absolute value of the timing advance adjustment counter does not exceed the adjustment threshold (i.e., determination block 810 = "no"), the processor may adjust the timing advance value maintained by the first subscription by the timing advance adjustment value received from the first network in block 814. In other words, the received timing advance adjustment value is likely correct and may be applied when the absolute value of the timing advance adjustment counter is less than a threshold.

In response to determining that the absolute value of the timing advance adjustment counter does exceed the adjustment threshold (i.e., determination block 810 = "yes"), the processor may ignore the timing advance adjustment value received from the first network in block 812. In other words, the received timing advance adjustment value is likely to be erroneous and should not be used when the absolute value of the timing advance adjustment counter exceeds a threshold.

After applying the received timing advance adjustment value in block 814 or ignoring the adjustment value in block 812, the processor may determine whether a new tune away has been initiated in determination block 816.

In response to determining that a new tune away has been initiated (i.e., determination block 816 = "yes"), the processor may initiate a new timing advance protection window within the time period in block 720. In other words, each new tune away may trigger a restart of the current timing advance protection window. When restarted, the adjustment threshold, the uplink transmission interval, the inactivity timer value, and the period of the short discontinuous reception cycle may be recalculated by the processor and utilized in a new timing advance protection window.

In response to determining that a new tune away has not been initiated (i.e., determination block 816 = "no"), the processor may determine whether the uplink transmission interval of the first subscription is within a predetermined range in determination block 818. The predetermined range may take into account a period in which the uplink transmission interval is long enough for the network to generate an erroneous timing advance adjustment value. For example, a timing advance guard window may be initiated when the uplink transmission interval is between an upper bound N and a lower bound M. In a non-limiting example, the lower limit M may be set to 10 subframes and the upper limit N may be set to 10240 subframes.

In response to determining that the uplink transmission interval is within the predetermined range (i.e., determination block 818 = "yes"), the processor may extend the time period of the timing advance guard window period by a predetermined amount in block 820. The predetermined amount may be the sum of the inactivity timer of the first subscription and the period of the short discontinuous reception cycle. The processor may obtain values for the inactivity timer and the period of the short discontinuous reception cycle from the first network.

In response to determining that the uplink transmission interval is not within the predetermined range (i.e., determination block 818 = "no"), or after extending the timing advance protection window period in block 820, the processor may determine whether the timing advance protection window period has expired in determination block 822.

In response to determining that the timing advance guard window period has not expired (i.e., determination block 822 = "no"), the processor may re-determine whether the uplink transmission interval exceeds a predetermined upper limit in determination block 806. In other words, when the timing advance protection window has not expired, the processor may determine whether to apply or ignore the next received timing advance adjustment value from the first network.

In response to determining that the timing advance protection window time period has expired (i.e., determination block 822 = "yes"), the processor may terminate the timing advance protection window and resume determining the uplink transmission interval in block 702. In other words, the current timing advance protection window may terminate, and the processor may begin a new timing advance protection window at a future time (e.g., when a future uplink transmission interval falls within a predetermined range). In this manner, the method 800 provides adaptive monitoring and protection of timing advance adjustment values triggered by tune away.

The various examples may be implemented in any of a variety of multi-SIM communication devices, an example of which (e.g., multi-SIM communication device 900) is shown in fig. 9. Referring to fig. 1-9, a multi-SIM communication device 900 may be similar to multi-SIM communication devices 110, 120, 200 and may implement methods 700 and 800.

The multi-SIM communication device 900 can include a processor 902 coupled to a touchscreen controller 904 and an internal memory 906. The processor 902 may be one or more multi-core integrated circuits designated for general or specific processing tasks. The internal memory 906 may be volatile or non-volatile memory, and may also be secure and/or encrypted memory, or unsecure and/or unencrypted memory, or any combination of the above. The touchscreen controller 904 and the processor 902 may also be coupled to a touchscreen panel 912, such as a resistive-sensing touchscreen, a capacitive-sensing touchscreen, an infrared-sensing touchscreen, or the like. Additionally, the display of the multi-SIM communication device 900 need not have touch screen functionality.

The multi-SIM communication device 900 may have one or more cellular network transceivers 908 coupled to the processor 902 and to one or more antennas 910 and configured for sending and receiving cellular communications. One or more transceivers 908 and one or more antennas 910 may be used with the above-described circuitry to implement various example methods. The multi-SIM communication device 900 may include one or more SIM cards 916 coupled to one or more transceivers 908 and/or processors 902, and may be configured as described above.

The multi-SIM communication device 900 may also include a speaker 914 for providing audio output. The multi-SIM communication device 900 may also include a housing 920, the housing 920 being constructed of plastic, metal, or a combination of materials for housing all or some of the components discussed herein. The multi-SIM communication device 900 may include a power supply 922, such as a disposable or rechargeable battery, coupled to the processor 902. The rechargeable battery may also be coupled to the peripheral device connection port to receive a charging current from a source external to the multi-SIM communication device 900. The multi-SIM communication device 900 may also include physical buttons 924 for receiving user input. The multi-SIM communication device 900 may also include a power button 926 for turning the multi-SIM communication device 900 on and off.

The foregoing method descriptions and process flow diagrams are provided merely as illustrative examples and are not intended to require or imply that the steps of the various examples must be performed in the order shown. As one of ordinary skill in the art will appreciate, the order of the steps in the foregoing examples may be performed in any order. Words such as "thereafter," "then," "next," etc. are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the methods. Furthermore, any reference to claim elements in the singular, for example, using the articles "a," "an," or "the," is not to be construed as limiting the element to the singular.

The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the examples disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The hardware used to implement the various illustrative logics, logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Alternatively, some steps or methods may be performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a non-transitory computer-readable storage medium or a non-transitory processor-readable storage medium. The steps of a method or algorithm disclosed herein may be embodied in a processor-executable software module residing on a non-transitory computer-readable or processor-readable storage medium. A non-transitory computer-readable or processor-readable storage medium may be any storage medium that can be accessed by a computer or a processor. By way of example, and not limitation, such non-transitory computer-readable or processor-readable storage media can comprise RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of non-transitory computer-readable and processor-readable media. Further, the operations of a method or algorithm may exist as one or any combination or set of codes and/or instructions that may be incorporated onto a non-transitory processor-readable storage medium and/or computer-readable storage medium of a computer program product.

The previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to some examples without departing from the spirit or scope of the written description. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein.

Claims (30)

1. A method for a mobile communication device, comprising:

determining an uplink transmission interval for a first subscription of the mobile communication device;

initiating a timing advance protection window when a tune away occurs from the first subscription to another subscription, or when the uplink transmission interval for the first subscription is within a predetermined range having a minimum value; and

during the timing advance guard window:

determining an adjustment threshold based on the uplink transmission interval;

incrementing a timing advance adjustment counter by a timing advance adjustment value received from the first network;

determining whether an absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

2. The method of claim 1, further comprising: adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter does not exceed the adjustment threshold.

3. The method of claim 1, further comprising:

determining whether the uplink transmission interval is within a predetermined range; and

adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval is not within the predetermined range.

4. The method of claim 1, further comprising:

determining, in response to a transmission sent from the first subscription to the first network, whether the first subscription has received a predetermined response pattern from the first network; and

adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the first subscription has received the predetermined response pattern from the first network.

5. The method of claim 4, wherein the predetermined response pattern comprises a threshold number of consecutive acknowledgements.

6. The method of claim 1, further comprising:

determining whether a timing advance guard window time period has expired; and

adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the timing advance protection window time period has expired.

7. The method of claim 6, wherein the timing advance protection window period comprises a sum of an inactivity timer of the first subscription and a period of a short discontinuous reception cycle.

8. The method of claim 1, further comprising:

determining whether a tune away from the first subscription to a second subscription of the mobile communication device has been initiated; and

initiating a new timing advance protection window period in response to determining that the tune away has been initiated.

9. The method of claim 8, further comprising:

determining whether the uplink transmission interval is within a predetermined range; and

extending the new timing advance protection window time period in response to determining that the uplink transmission interval is within the predetermined range.

10. The method of claim 9, wherein the new timing advance protection window time period is extended by a sum of an inactivity timer of the first subscription and a period of a short discontinuous reception cycle.

11. The method of claim 8, further comprising:

determining whether the uplink transmission interval exceeds a predetermined upper limit; and

adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval exceeds the predetermined upper limit.

12. The method of claim 1, wherein determining the adjustment threshold is further based on an estimated velocity of the mobile communication device.

13. The method of claim 1, further comprising:

determining the uplink transmission interval for each of a plurality of timing advance groups, wherein each timing advance group comprises one or more component carriers of the first subscription;

determining, for each of the plurality of timing advance groups, the adjustment threshold based on the uplink transmission interval;

incrementing the timing advance adjustment counter by the timing advance adjustment value received from the first network for each of the plurality of timing advance groups;

determining, for each of the plurality of timing advance groups, whether the absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value for any timing advance group of the plurality of timing advance groups for which the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

14. A mobile communication device, comprising:

a memory;

a Radio Frequency (RF) resource; and

a processor, coupled to the memory and the RF resource, configured to connect a first Subscriber Identity Module (SIM) associated with a first subscription and a second SIM associated with a second subscription, and configured to:

determining an uplink transmission interval for the first subscription;

initiating a timing advance protection window when a tune away occurs from the first subscription to another subscription, or when the uplink transmission interval for the first subscription is within a predetermined range having a minimum value; and

during the timing advance guard window:

determining an adjustment threshold based on the uplink transmission interval;

incrementing a timing advance adjustment counter by a timing advance adjustment value received from the first network;

determining whether an absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

15. The mobile communication device of claim 14, wherein the processor is further configured to: adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter does not exceed the adjustment threshold.

16. The mobile communication device of claim 14, wherein the processor is further configured to:

determining whether the uplink transmission interval is within a predetermined range; and

adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval is not within the predetermined range.

17. The mobile communication device of claim 14, wherein the processor is further configured to:

determining, in response to a transmission sent from the first subscription to the first network, whether the first subscription has received a predetermined response pattern from the first network; and

adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the first subscription has received the predetermined response pattern from the first network.

18. The mobile communication device of claim 17, wherein the predetermined response pattern comprises a threshold number of consecutive acknowledgements.

19. The mobile communication device of claim 14, wherein the processor is further configured to:

determining whether a timing advance guard window time period has expired; and

adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the timing advance protection window time period has expired.

20. The mobile communication device of claim 19, wherein the processor is further configured to: adjusting the timing advance value associated with the first subscription by the timing advance adjustment value based on a sum of an inactivity timer of the first subscription and a period of a short discontinuous reception cycle.

21. The mobile communication device of claim 14, wherein the processor is further configured to:

determining whether a tune away of the RF resource from the first subscription to the second subscription has been initiated; and

initiating a new timing advance protection window period in response to determining that the tune away has been initiated.

22. The mobile communication device of claim 21, wherein the processor is further configured to:

determining whether the uplink transmission interval is within a predetermined range; and

extending the new timing advance protection window time period in response to determining that the uplink transmission interval is within the predetermined range.

23. The mobile communication device of claim 22, wherein the processor is further configured to: extending the new timing advance guard window time period by a sum of the inactivity timer of the first subscription and a period of a short discontinuous reception cycle.

24. The mobile communication device of claim 21, wherein the processor is further configured to:

determining whether the uplink transmission interval exceeds a predetermined upper limit; and

adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval exceeds the predetermined upper limit.

25. The mobile communication device of claim 14, wherein the processor is further configured to: determining an adjustment threshold based on the uplink transmission interval based on the estimated speed of the mobile communication device.

26. The mobile communication device of claim 14, wherein the processor is further configured to:

determining the uplink transmission interval for each of a plurality of timing advance groups, wherein each timing advance group comprises one or more component carriers of the first subscription;

determining, for each of the plurality of timing advance groups, the adjustment threshold based on the uplink transmission interval;

incrementing the timing advance adjustment counter by the timing advance adjustment value received from the first network for each of the plurality of timing advance groups;

determining, for each of the plurality of timing advance groups, whether the absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value for any timing advance group of the plurality of timing advance groups for which the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

27. A non-transitory computer readable storage medium having stored thereon processor-executable software instructions configured to cause a processor of a mobile communication device to perform operations comprising:

determining an uplink transmission interval for a first subscription of the mobile communication device;

initiating a timing advance protection window when a tune away occurs from the first subscription to another subscription, or when the uplink transmission interval for the first subscription is within a predetermined range having a minimum value; and

during the timing advance guard window:

determining an adjustment threshold based on the uplink transmission interval;

incrementing a timing advance adjustment counter by a timing advance adjustment value received from the first network;

determining whether an absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

28. The non-transitory computer readable storage medium of claim 27, wherein the stored processor-executable instructions are configured to cause the processor of the mobile communication device to perform operations further comprising:

determining whether the uplink transmission interval is within a predetermined range; and

adjusting a timing advance value associated with the first subscription by the timing advance adjustment value in response to determining that the uplink transmission interval is not within the predetermined range.

29. The non-transitory computer readable storage medium of claim 27, wherein the stored processor-executable instructions are configured to cause the processor of the mobile communication device to perform operations further comprising:

determining, in response to a transmission sent from the first subscription to the first network, whether the first subscription has received a predetermined response pattern from the first network; and

adjusting, by the timing advance adjustment value, a timing advance value associated with the first subscription in response to determining that the first subscription has received the predetermined response pattern from the first network.

30. A mobile communication device, comprising:

means for determining an uplink transmission interval for a first subscription of the mobile communication device;

means for initiating a timing advance protection window when a tune away occurs from the first subscription to another subscription, or when the uplink transmission interval for the first subscription is within a predetermined range having a minimum value; and

means for, during the timing advance protection window:

determining an adjustment threshold based on the uplink transmission interval;

incrementing a timing advance adjustment counter by a timing advance adjustment value received from the first network;

determining whether an absolute value of the timing advance adjustment counter exceeds the adjustment threshold; and

ignoring the timing advance adjustment value in response to determining that the absolute value of the timing advance adjustment counter exceeds the adjustment threshold.

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