PATENT DOCUMENT

Publication Number: US-9125138-B2
Application Number: US-201213663005-A
Country: US
Kind Code: B2

Title: System and method for optimizing video conferencing in a wireless device

Abstract:
A wireless device described herein can use information on data flow, in addition to indications from the physical network, to decide on suitable bandwidth usage for audio and video information. This data flow information is further used to determine an efficient network route to use for high-quality reception and transmission of audio and video data, as well as the appropriate time to switch between available network routes to improve bandwidth performance.

Claims:
What is claimed is: 
     
       1. A method of videoconferencing in a wireless network, the method comprising:
 determining at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system, each communication route being associated with at least one of a plurality of antennas; 
 selecting an antenna based on the one or more route quality indicators; 
 determining a transition time based on an entropy of videoconference audio and/or video data and transitioning to the selected antenna after the transition time; and 
 transmitting, from the wireless device to the remote system, the videoconference audio and/or video data via the selected antenna. 
 
     
     
       2. The method of  claim 1 , wherein the at least one route quality indicator comprises at least one of: a network statistic, a radio performance metric, a user performance metric, and a predictive performance metric. 
     
     
       3. The method of  claim 2 , wherein the network statistic comprises at least one of: a one-way network latency, a round-trip time, a packet loss pattern, an available bandwidth, an end-to-end network latency, an end-to-end packet loss, and a jitter. 
     
     
       4. The method of  claim 2 , wherein the radio performance metric comprises at least one of: a Signal-to-Noise Ratio (SNR), a transmit power level, and a Received Signal Strength Indication (RSSI). 
     
     
       5. The method of  claim 2 , wherein the user performance metric comprises at least one of: a thermal metric, a power consumption rate, a CPU load, a buffer occupancy, a media playback state, a media playback configuration, and a user communication route preference. 
     
     
       6. The method of  claim 1 , wherein selecting the antenna comprises selecting an antenna associated with the non-selected communication route, when the one or more route quality indicators for the selected communication route are below a threshold. 
     
     
       7. The method of  claim 6 , wherein the threshold is based on the one or more route quality indicators for the selected communication route. 
     
     
       8. The method of  claim 1 , further comprising determining an entropy value for a portion of the video or audio data and transitioning to the selected antenna when the entropy is below a threshold. 
     
     
       9. A wireless device configured to perform videoconferencing in a wireless network, the wireless device comprising:
 a plurality of antennas; 
 a network quality module configured determine at least one route quality indicator of a videoconference session for each of a plurality of communication routes between the wireless device and a remote system, each communication route being associated with at least one of the plurality of antennas; 
 an antenna switching module configured to select an antenna based on the one or more route quality indicators, wherein the switching module is further configured to determine a transition time based on an entropy of videoconference audio and/or video data and transitioning to the selected antenna after the transition time; and 
 a transmitter configured to transmit, from the wireless device to the remote system, the videoconference audio and/or video data via the selected antenna. 
 
     
     
       10. The wireless device of  claim 9 , wherein the at least one route quality indicator comprises at least one of: a network statistic, a radio performance metric, a user performance metric, and a predictive performance metric. 
     
     
       11. The wireless device of  claim 10 , wherein the network statistic comprises at least one of: an end-to-end network latency, an end-to-end packet loss, and a jitter. 
     
     
       12. The wireless device of  claim 10 , wherein the radio performance metric comprises at least one of: a Signal-to-Noise Ratio (SNR), a transmit power level, and a Received Signal Strength Indication (RSSI). 
     
     
       13. The wireless device of  claim 10 , wherein the user performance metric comprises at least one of: a CPU load, a buffer occupancy, a media playback state, a media playback configuration, and a user communication route preference. 
     
     
       14. The wireless device of  claim 9 , wherein the network quality module is configured to determine an entropy value for a portion of the video or audio data. 
     
     
       15. An apparatus for videoconferencing in a wireless network, the apparatus comprising:
 means for determining at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system, each communication route being associated with at least one of a plurality of antennas; 
 means for selecting an antenna based on the one or more route quality indicators; 
 means for determining a transition time based on an entropy of videoconference audio and/or video data and transitioning to an antenna selected by the means for selecting after the transition time; and 
 means for transmitting, from the wireless device to the remote system, the videoconference audio and/or video data via the selected antenna. 
 
     
     
       16. The apparatus of  claim 15 , wherein the means for selecting the antenna comprises means for selecting an antenna associated with the non-selected communication route, when the one or more route quality indicators for the selected communication route are below a threshold. 
     
     
       17. A non-transitory computer-readable medium comprising code that, when executed by one or more processors, causes an apparatus to:
 determine at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system, each communication route being associated with at least one of a plurality of antennas; 
 select an antenna based on the one or more route quality indicators; 
 determine a transition time based on an entropy of videoconference audio and/or video data and transitioning to the selected antenna after the transition time; and 
 transmit, from the wireless device to the remote system, the videoconference audio and/or video data via the selected antenna. 
 
     
     
       18. The medium of  claim 17 , wherein the at least one route quality indicator comprises at least one of: a network statistic, a radio performance metric, a user performance metric, and a predictive performance metric. 
     
     
       19. The medium of  claim 18 , wherein the network statistic comprises at least one of: an end-to-end network latency, an end-to-end packet loss, and a jitter. 
     
     
       20. The medium of  claim 18 , wherein the radio performance metric comprises at least one of: a Signal-to-Noise Ratio (SNR), a transmit power level, and a Received Signal Strength Indication (RSSI).

Description:
PRIORITY CLAIM 
     This application claims benefit of priority to U.S. Provisional Application No. 61/605,082 entitled “System and Method for Optimizing Video Conferencing in a Wireless Device” and filed on Feb. 29, 2012, and which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to data communications, and more particularly, to a method for managing performance of audio and/or video conferencing in varying network conditions. 
     DESCRIPTION OF THE RELATED TECHNOLOGY 
     Handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. 
     Due in part to their mobile nature, handheld electronic devices are often provided with wireless communications capabilities. Handheld electronic devices may use long-range wireless communications to communicate with wireless base stations. For example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 20 MHz, and 1900 MHz. Handheld electronic devices may also use short-range wireless communications links For example, handheld electronic devices may communicate using the WiFi® (IEEE 802.11) band at 2.4 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in data service 25 bands such as the 3G data communications band at 2170 MHz (commonly referred to as the UMTS or Universal Mobile Telecommunications System band). Because of the various wireless frequencies used by each band, communication links within each device can use one or more antennas. 
     One application of handheld electronic devices is videoconferencing, which can be performed in conjunction with an electronic device, handheld or otherwise. Videoconferencing systems facilitate both audio and video communication among participants over a network. A conventional video conferencing system includes near end and far end components. In a conventional videoconferencing system, video and/or audio data associated with a near end user is captured by a near end video camera or other capture device. The near end captured data is transmitted to a far end receiver and presented to a far end user. Far end captured data is received from a far end transmitter and presented to the near end user. The data can be transferred over one or more communications links available to the electronic device. 
     SUMMARY 
     The systems, methods and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein. 
     One innovative aspect of the subject matter described in this disclosure can be implemented in a method of videoconferencing in a wireless network. The method includes determining at least one route quality indicator for each of a plurality of communication routes between a wireless device and a remote system. Each communication route is associated with at least one of a plurality of antennas. The method further includes selecting an antenna based on the one or more route quality indicators. The method further includes transmitting, from the wireless device to the remote system, video and/or audio data via the selected antenna. 
     In an embodiment, the at least one route quality indicator can include at least one of: a network statistic, a radio performance metric, a user performance metric, and a predictive performance metric. The network statistic can include at least one of: a one-way network latency, a round-trip time, a packet loss pattern, an available bandwidth, an end-to-end network latency, an end-to-end packet loss, and a jitter. The radio performance metric can include at least one of: a Signal-to-Noise Ratio (SNR), a transmit power level, and a Received Signal Strength Indication (RSSI). The user performance metric can include at least one of: a thermal metric, a power consumption rate, a CPU load, a buffer occupancy, a media playback state, a media playback configuration, and a user communication route preference. 
     In another embodiment, selecting the antenna can include selecting an antenna associated with the non-selected communication route, when the one or more route quality indicators for the selected communication route are below a threshold. The threshold can be based on the one or more route quality indicators for the selected communication route. 
     In another embodiment, the method can further include determining at least one route quality indicator for a non-selected communication route of the plurality of communication routes. The method can further include transmitting a test communication via the non-selected communication route. The method can further include determining the at least one route quality indicator for the non-selected communication route based on the test communication. Selecting the antenna can include selecting an antenna associated with the non-selected communication route when the one or more route quality indicators for the non-selected communication route are above a threshold. The threshold can be based on the one or more route quality indicators for the selected communication route. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of videoconferencing in a wireless network. The method includes transmitting, from the wireless device to the remote system, video and/or audio data via a first antenna. The method further includes selecting a second antenna based on one or more route quality indicators. The method further includes determining a transition time based on an entropy of the video and/or audio data. The method further includes transitioning to the second antenna after the transition time. 
     In an embodiment, the method can further include determining an entropy value for a portion of the video and/or audio data. The method can further include transitioning to the selected communication route when the entropy is below a threshold. The method can further include refraining from transitioning to another antenna for a first time period after transitioning transmission to the second antenna. The method can further include sending a refresh signal to a media encoder. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of videoconferencing in a wireless network. The method includes transmitting, from the wireless device to the remote system, video and/or audio data via a first antenna. The method further includes selecting a second antenna based on one or more route quality indicators. The method further includes filling a transmission queue associated with the second antenna prior to transitioning transmission to the second antenna. The method further includes transitioning transmission to the second antenna. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of videoconferencing in a wireless network. The method includes transmitting, from the wireless device to the remote system, video and/or audio data via a first antenna. The method further includes selecting a second antenna based on one or more route quality indicators. The method further includes reducing a transfer rate of the video and/or audio data prior to transitioning to the second antenna. The method further includes transitioning transmission to the second antenna. 
     In an embodiment, the method can further include restoring an original transfer rate after to transitioning transmission to the second antenna. The method can further include adjusting the transfer rate of video and/or audio data, after transitioning to the second antenna, based on the one or more route quality indicators. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless device configured to perform videoconferencing in a wireless network. The wireless device includes one or more processors configured to determine at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system. Each communication route is associated with at least one of a plurality of antennas. The one or more processors are further configured to select an antenna based on the one or more route quality indicators. The wireless device further includes a transmitter configured to transmit, from the wireless device to the remote system, videoconference audio or video data via the selected antenna. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in an apparatus for videoconferencing in a wireless network. The apparatus includes means for determining at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system. Each communication route is associated with at least one of a plurality of antennas. The apparatus further includes means for selecting an antenna based on the one or more route quality indicators. The apparatus further includes means for transmitting, from the wireless device to the remote system, videoconference audio or video data via the selected antenna. 
     Another innovative aspect of the subject matter described in this disclosure can be implemented in a non-transitory computer-readable medium. The medium includes code that, when executed by one or more processors, causes an apparatus to determine at least one route quality indicator of a videoconference session for each of a plurality of communication routes between a wireless device and a remote system. Each communication route is associated with at least one of a plurality of antennas. The medium further includes code that, when executed by one or more processors, causes the apparatus to select an antenna based on the one or more route quality indicators. The medium further includes code that, when executed by one or more processors, causes the apparatus to transmit, from the wireless device to the remote system, videoconference audio or video data via the selected antenna. 
     Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an exemplary videoconferencing communication system. 
         FIG. 2  shows an exemplary wireless device configured to perform videoconferencing. 
         FIG. 3  is a flowchart depicting an exemplary method of selecting an antenna in the videoconferencing communication system of  FIG. 1 . 
         FIG. 4  is a flowchart depicting an exemplary method of determining a network quality metric. 
         FIG. 5  is a flowchart depicting an exemplary method of determining an antenna quality metric. 
         FIG. 6  is a flowchart depicting an exemplary method of determining a user performance metric. 
         FIG. 7  is a flowchart depicting an exemplary method of determining a predictive performance metric. 
         FIG. 8  is a flowchart depicting an exemplary method of performing pre-activation functions. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     One embodiment is a system and method for providing an enhanced videoconferencing capability for a wireless device. In one embodiment, a wireless device that is programmed with videoconferencing functions includes one or more modules configured to determine the quality of a variety of network routes that can accept the videoconferencing data. The device is programmed to compare the quality of each network route and select the highest quality route for the videoconferencing data. In this embodiment, the device may determine that a higher quality network route is available for the videoconference data, and then seamlessly and smoothly transfer the videoconference data to the higher quality network. 
     In one example, a first user may be performing a videoconference from a wireless device to second user. As the video conference call is progressing the wireless device may be programmed to determine the quality of the present videoconference. The device may also monitor data traffic and capacity on one or more alternative wireless data networks accessible by the device. If a determination is made that the videoconference could have improved quality by switching from a first network to a second network, the device will execute that switch to improve the videoconference call quality. In one example, the device may switch from a first cellular network system to a WiFi system. Because many new wireless devices, such as wireless telephone handsets and tablets have a plurality of antennas, they are able to communicate through a variety of different wireless protocols and standards. 
     In one embodiment, the device may detect that a threshold number of data packets have been lost. In another example, the device may detect that a new, higher bandwidth, network is available. The device may also be programmed by the user to automatically switch to a different network upon certain conditions being met. For example, the user may program the device to always switch from a cellular network to an available WiFi network to save cellular network costs and increase videoconference quality since a WiFi network normally has a higher bandwidth. 
     In yet another example, the device may store and retrieve past experience data to determine that a different network should be chosen. For example, the device may use an integrated GPS to store location data relating to geographic locations where data packet loss is very high. When the device later detects, through a GPS, that it is approaching an area of repeated data loss, it can switch to a different available network so that the videoconference call would not be dropped, or have its quality degraded. 
     In another embodiment, the device may detect its position in a user&#39;s hand to determine the proper antenna to use to communicate over the videoconference. For example, the device may include an accelerometer and a tilt detector, and thus be able to determine its orientation relative to the user. In addition, a proximity detector may be used to determine if the device is pressed against the user&#39;s face as in a normal telephone call. Using these data, the device may determine that one antenna or another is either more secure, or more reliable based on the orientation of the device with respect to the user. 
     In one embodiment, switching from one network to a second network is done in a way to minimize interference with the videoconference. For example, the device may be programmed to wait for a certain event to occur before switching. For example, device may be programmed to only switch networks during a momentary pause in the videoconference. 
     The following detailed description is directed to certain implementations for the purposes of describing the innovative aspects. However, the teachings herein can be applied in a multitude of different ways. The described implementations may be implemented in any device that is configured to perform wireless conferencing, including video and/or audio. More particularly, it is contemplated that the implementations may be implemented in or associated with a variety of electronic devices such as, but not limited to, mobile telephones, multimedia Internet enabled cellular telephones, wireless devices, smartphones, Bluetooth® devices, personal data assistants (PDAs), hand-held or portable computers, netbooks, notebooks, smartbooks, tablets, and a variety of electronic devices. The teachings herein also can be used in non-conferencing applications such as, but not limited to, one-way transmissions such as videocasting, audiocasting, and podcasting. Thus, the teachings are not intended to be limited to the implementations depicted solely in the Figures, but instead have wide applicability as will be readily apparent to a person having ordinary skill in the art. 
     The techniques described herein may be used for various wireless communication networks such as Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, etc. The terms “networks” and “systems” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). Long Term Evolution (LTE) is an upcoming release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards, and others, are known in the art. 
       FIG. 1  shows an exemplary videoconferencing communication system  100 . In the illustrated embodiment, the videoconferencing communication system  100  includes wireless devices  110   a - c . Although not shown, the videoconferencing communication system  100  can include additional wireless and/or wired devices (handheld or otherwise), in various embodiments. The wireless devices  110   a - c  can be configured to communicate with each other via one or more communication links  120   a - c . For example, the wireless devices  110   a - c  can exchange audio and/or video data. 
     The various communication links  120   a - c  can include any combination of wired and wireless technologies. For example, the communication link  120   a  can communicate data, at least in part, over a cellular data network  130   a . The cellular data network  130   a  can include communication link  120   b  can communicate data, at least in part, over a private network  130   b . The communication link  120   c  can communicate data, at least in part, over the Internet  130   b . Moreover, each communication link  120  can traverse a heterogeneous combination of networks types. 
     The wireless devices  110   a - c  include cameras  140   a - c , displays  142   a - c , and antennas  144   a - c  and  146   a - c . In various embodiments, the wireless devices  110   a - c  can include one or more additional audio and/or video sensors, such as microphones, photo-detectors, etc. The wireless devices  110   a - c  can further include one or more additional audio and/or video output devices, such as speakers, indicator lights, etc. In various embodiments, the wireless devices  110   a - c  can include greater or fewer antennas. 
     The antennas  144   a - c  and  146   a - c  serve to facilitate wireless communication between the wireless devices  110   a - c . In various embodiments, different antennas can be used in conjunction with different radio interfaces (see  FIG. 2 ). For example, the antennas  144   a - c  can be used in conjunction with a WiFi radio, and the antennas  146   a - c  can be used in conjunction with a UMTS radio. In other embodiments, the antennas  144   a - c  and  146   a - c  can provide space diversity for a single radio interface. As will be discussed herein with respect to  FIG. 2 , the antennas  144   a - c  and  146   a - c  can be paired with any combination of radio interfaces. 
       FIG. 2  shows an exemplary wireless device  110  configured to perform videoconferencing. In the illustrated embodiment, the wireless device  110  includes a processor  200 , a memory  210 , a radio interface  220 , a user interface  230 , antennas  144 ,  146 , and  250 , and a housing  260 . The wireless device  110  may be employed within the videoconferencing communication system  100 , described above with respect to  FIG. 1 . The wireless device  110  is an example of a device that may be configured to implement the various methods described herein. For example, the wireless device  110  may implement one or more functions of the wireless device  110   a - c.    
     The processor can serve to control operation of the wireless device  110 . The processor  200  may also be referred to as a central processing unit (CPU). The memory  210  serves to provide instructions and data to the processor  200 . The memory  210  can include read-only memory (ROM) and/or random access memory (RAM). A portion of the memory  210  can also include non-volatile random access memory (NVRAM). The processor  200  can perform logical and arithmetic operations based on program instructions stored within the memory  210 . The instructions in the memory  210  can be executable to implement the methods described herein. 
     In an embodiment, the processor can be configured to execute a videoconferencing application in conjunction with one or more components of the wireless device  120 . For example, the processor  210  can read the videoconferencing application from the memory  210 , record video and/or audio via the user interface  230 , transmit the video and/or audio to a remote device via the radio interface  220  and the one or more antennas  144 ,  146 , and  250 . The processor  210  can also receive video and/or audio from the remote device via the radio interface  220  and the one or more antennas  144 ,  146 , and  250 , and present the video and/or audio to a user via the user interface  230 . 
     When the wireless device  110  communicates with the remote device, for example during a videoconference call, the audio and/or video data can traverse one or more network routes. Each network route can include a data path from the wireless device  110  to another device (for example, from the wireless device  110   a  to the wireless device  110   b  discussed above with respect to  FIG. 1 ). 
     For example, the processor  200  may generate a communication link (such as videoconference data), and may select a radio and an antenna over which to transmit the communication. The communication may traverse one or more network access points, switches, routers, etc., before reaching a destination device. Accordingly, each network route can be associated with a particular radio, and a particular antenna. 
     Although the wireless device  110  has access to a plurality of network routes, not all routes are necessarily of the same quality. Certain network routes may be slow, for example, network routes that include a low bandwidth radio or a poorly tuned antenna. In an embodiment, an antenna may become detuned due to a relative position of a device user. Other routes may include quality radio paths (such as a fast link between the wireless device  110  and a base station) but may experience congestion due to a bottleneck on a base station&#39;s backhaul link. In various embodiments described herein, the wireless device  110  can include one or more modules configured to determine the a quality of a plurality of network routes, select a high quality route, effect a smooth transition to the selected network route, and/or manage communications over the selected network route after the transition. 
     Referring still to  FIG. 2 , the processor  200  can include one or more modules, including an antenna switching module  272 , an antenna quality module  274 , a network quality module  276 , a user performance module  278 , and a predictive performance module  280 . As will be discussed herein with respect to  FIG. 3 , the antenna switching module  272  can serve to determine which antenna to use when transmitting and/or receiving videoconferencing data such as video and/or audio data. 
     As will be discussed herein with respect to  FIG. 4 , the antenna quality module can serve to determine an antenna quality metric, which the antenna switching module  272  can use to determine an antenna to use. Also, as will be discussed herein with respect to  FIG. 5 , the network quality module  276  can serve to determine a network quality metric, which the antenna switching module  272  can use to determine an antenna to use. In addition, as will be discussed herein with respect to  FIG. 6 , the user performance module  278  can serve to determine a user performance metric, which the antenna switching module  272  can use to determine an antenna to use. Further, as will be discussed herein with respect to  FIG. 7 , the predictive performance module  280  can serve to determine a network quality metric, which the antenna switching module  272  can use to determine an antenna to use. 
     Referring again to  FIG. 2 , in various embodiments, the modules  272 ,  274 ,  276 ,  278 , and  280  can include one or more hardware components, and/or one or more software components. The modules  272 ,  274 , and  276  can be implemented in conjunction with one or more other components of the processor  200 , including the memory  210 , the user interface  230 , the radio interface  220 , the antennas  144 ,  146 , and  250 , etc. 
     In various embodiments, the processor  200  can comprise or be a component of a processing system implemented with one or more processors. The one or more processors can be implemented with any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate array (FPGAs), programmable logic devices (PLDs), controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable entities that may perform calculations or other manipulations of information. 
     The processing system may also include machine-readable media for storing software. Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein. 
     The radio interface  220  can serve to provide an interface between various components of the wireless device  110  (such as, for example, the processor  200 ), and one or more radios  282 ,  284 , and  286 . The radio interface can include one or more WiFi radios, one or more Bluetooth® radios, one or more cellular radios (for example, a UMTS radio), etc. In various embodiments, the radios  282 ,  284 , and  286  can transmit and receive data via the antennas  144 ,  146 ,  250 , in various combinations. For example, some of the radios  282 ,  284 , and  286  can have a one-to-one relationship with the antennas  144 ,  146 ,  250 . Other radios  282 ,  284 , and  286  can have a one-to-many relationship with the antennas  144 ,  146 ,  250 . The various radios  282 ,  284 , and  286  can also share the antennas  144 ,  146 ,  250 . In various embodiments, one or more of the antennas  144 ,  146 ,  250  can be integrated into the housing  260 . In some embodiments, one or more antenna of the antennas  144 ,  146 ,  250  may be omitted, and the wireless device  110  may be configured for wired communication. 
     The user interface  230  can include, for example, the camera  140  ( FIG. 1 ), the display  142 , a proximity detector, one or more input buttons, a microphone, a speaker, and/or an interface port (for example, a Universal Serial Bus (USB) port, a High-Definition Multimedia Interface (HDMI) port, etc.). The display  142  can include a touchscreen. The user interface  230  can include any element or component that conveys information to a user of the wireless device  110  and/or receives input from the user. 
     In the illustrated embodiment, various components of the wireless device  110  are coupled together by a bus system  290 . The bus system  290  can include a data bus, for example, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus. Those of skill in the art will appreciate the components of the wireless device  110  may be coupled together or accept or provide inputs to each other using some other mechanism. 
     Although a number of separate components are illustrated in  FIG. 2 , those of skill in the art will recognize that one or more of the components may be combined or commonly implemented. Further, each of the components illustrated in  FIG. 2  may be implemented using a plurality of separate elements. 
       FIG. 3  is a flowchart  300  depicting an exemplary method of selecting an antenna in the videoconferencing communication system  100  of  FIG. 1 . Although the method of flowchart  300  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  300  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  300  may be performed by the antenna switching module  272  ( FIG. 2 ), in conjunction with one or more of the antenna quality module  274 , the network quality module  276 , the user performance module  278 , the predictive performance module  280 , the processor  200 , the memory  210 , and the antennas  144 ,  146 , and  250 . Although the method of flowchart  300  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  305 , the antenna switching module  272  determines a route quality indicator for an active antenna. The active antenna can be, for example, an antenna over which video and/or audio data is currently transmitted, or an antenna over which video and/or audio data is scheduled for transmission. In an embodiment, the active antenna is “active” with respect to a particular videoconferencing session. In another embodiment, the active antenna is “active” with respect to all transmissions from the wireless device  110 . The route quality indicator can include one or more of a network quality metric, an antenna quality metric, a user performance metric, and a predictive performance metric. 
     In various embodiments, the antenna switching module  272  can determine the route quality indicator in conjunction with one or more of the antenna quality module  274 , the network quality module  276 , the user performance module  278 , and the predictive performance module  280 . For example, the antenna switching module  272  can determine the network quality metric in conjunction with the network quality module  276 . The antenna switching module  272  can also determine the antenna quality metric in conjunction with the antenna quality module  274 . The antenna switching module  272  can also determine the user performance metric in conjunction with the user performance module  278 . The antenna switching module  272  can also determine the predictive performance metric in conjunction with the predictive performance module  280 . 
     Next, at block  310 , the antenna switching module  272  compares the route quality indicator to a switching threshold value. The switching threshold can indicate a minimum route quality below which the antenna switching module  272  should attempt to switch antennas. In various embodiments, the switching threshold can be retrieved from the memory  210 , or dynamically computed by the processor  200 . 
     In an embodiment, the antenna switching module  272  can compare one or more components of the route quality indicator to one or more respective thresholds. For example, the antenna switching module  272  can compare a network quality metric, received from the network quality module  276 , to a network quality switching threshold. Similarly, the antenna switching module  272  can compare an antenna quality metric, received from the antenna quality module  274 , to an antenna quality switching threshold. The antenna switching module  272  can also compare a user performance metric, received from the user performance module  276 , to a user performance switching threshold. The antenna switching module  272  can also compare a predictive performance metric, received from the predictive performance module  280 , to a predictive performance switching threshold. In embodiments where the route quality indicator is a function of the one or more component metrics described herein, the antenna switching module  272  can compare the route quality indicator to a combined activation threshold. 
     Referring still to  FIG. 3 , if the route quality indicator is at or above the switching threshold, the antenna switching module  272  can determine that the active antenna is performing acceptably at block  315 . Accordingly, the antenna switching module  272  may not switch antennas. On the other hand, if the route quality indicator is below the switching threshold, the antenna switching module  272  can begin searching for an acceptable alternative antenna at block  320 . 
     In one embodiment, the antenna switching module  272  can search for an alternative antenna, even when the route quality indicator is at or above the switching threshold. For example, the antenna switching module  272  can proceed to block  320  to determine whether another antenna has a higher route quality indicator. In an embodiment, the antenna switching module  272  can determine which alternative antenna has the highest route quality indicator. 
     Then, at block  320 , the antenna switching module  272  selects an inactive antenna, which may be a candidate for activation. The antenna switching module  272  can select a candidate inactive antenna be iterating through inactive antennas, randomly choosing an antenna, or any other method. In an embodiment, an “inactive” antenna is inactive with respect to a particular data session, such as a particular video conference. For example, an antenna that is inactive with respect to a particular video conferencing session may still be in use with respect to other data applications. In another embodiment, an “inactive” antenna can be inactive with respect to all data transmissions of the wireless device  110 . 
     Thereafter, at block  325 , the antenna switching module  272  determines a route quality indicator for the selected inactive antenna. As discussed above, the route quality indicator can include one or more of a network quality metric, an antenna quality metric, a user performance metric, and a predictive performance metric. The antenna switching module  272  can determine the route quality indicator in conjunction with one or more of the antenna quality module  274 , the network quality module  276 , the user performance module  278 , and the predictive performance module  280 . 
     Subsequently, at block  330 , the antenna switching module  272  compares the route quality indicator to an activation threshold value. The activation threshold can indicate a route quality above which the antenna switching module  272  should switch antennas by activating the selected candidate inactive antenna. In various embodiments, the activation threshold can be retrieved from the memory  210 , or dynamically computed by the processor  200 . 
     In an embodiment, the antenna switching module  272  can compare one or more components of the route quality indicator to one or more respective thresholds. For example, the antenna switching module  272  can compare a network quality metric, received from the network quality module  276 , to a network quality activation threshold. Similarly, the antenna switching module  272  can compare an antenna quality metric, received from the antenna quality module  274 , to an antenna quality activation threshold. In embodiments where the route quality indicator is a function of the one or more component metrics described herein, the antenna switching module  272  can compare the route quality indicator to a combined switching threshold. 
     Referring still to  FIG. 3 , if the route quality indicator is at or below the activation threshold, the antenna switching module  272  can determine that the selected candidate antenna is not acceptable, and can attempt to select another candidate antenna. At block  335 , the antenna switching module  272  determines whether another candidate antenna is available. If so, the antenna switching module  272  selects another candidate antenna at block  300 . Otherwise, the antenna switching module  272  can determine that there is not a more acceptable antenna available at block  315 . 
     Referring again to block  330 , if the route quality indicator is above the activation threshold, the antenna switching module  272  can determine that the candidate antenna should be activated. In one embodiment, the antenna switching module  272  may check all available channels to find the best quality channel. For example, the antenna switching module  272  may select another candidate antenna at block  300 , even when the route quality indicator for the currently selected candidate antenna is above the activation threshold. After checking all available channels, the antenna switching module  272  may select the antenna with the highest route quality indicator for activation at block  315 . 
     In an embodiment, the antenna switching module  272  may not switch antennas immediately. Instead, the antenna switching module  272  can perform one or more pre-activation functions at block  340 . As will be described herein with respect to  FIG. 8 , the pre-activation functions can serve to minimize perceived disruption to a media stream. For example, the antenna switching module  272  can determine an acceptable time at which to switch antennas, pre-fill the baseband queue of the candidate antenna before switching to the candidate antenna, and/or throttle the media stream prior to activating the new antenna. 
     Then, at block  345 , the antenna switching module  272  activates the selected candidate antenna. In an embodiment, the antenna switching module  272  can activate the selected candidate antenna by sending and/or receiving subsequent data over that antenna. In various embodiments, the antenna switching module  272  can deactivate the original active antenna, or otherwise cease transmission of data over the original antenna. 
     As described above with respect to embodiment of  FIG. 3 , the antenna switching module  272  is configured switch antennas when the active antenna falls below a first threshold quality level, and an inactive antenna exceeds a second threshold quality level. By way of non-limiting example, the antenna switching module  272  may determine a signal-to-noise ratio (SNR) of the active antenna in conjunction with the antenna quality module  274 . If the SNR of the active antenna falls below a switching SNR threshold, the antenna switching module  272  may attempt to find another antenna with a better SNR. If the antenna switching module  272  finds a candidate inactive antenna with an SNR above an activation SNR threshold, the antenna switching module  272  may switch communications to the candidate antenna. The various switching thresholds and activation thresholds can be the same value, although they may also be different. 
     In another embodiment, the antenna switching module  272  may omit the search for a “better” antenna. In other words, the antenna switching module  272  can be configured to switch antennas when the route quality of communications over the active antenna drop below the switching threshold, regardless of a route quality with respect to any other antenna. For example, the antenna switching module  272  can switch to an inactive antenna (for example, on a round-robin, random, or pseudorandom basis). If the newly activated antenna is also unacceptable, the antenna switching module  272  may keep switching to other inactive antennas until an acceptable antenna is activated. 
     In yet another embodiment, the antenna switching module  272  may omit determination of the route quality indicator for the active antenna. For example, the antenna switching module  272  may continuously or intermittently search for a “better” antenna by polling the route quality indicator for inactive antennas (for example, on a round-robin, random, or pseudorandom basis). Thus, the antenna switching module  272  can be configured to switch antennas when the route quality with respect to an inactive antenna exceeds the activation threshold, regardless of a route quality with respect to the active antenna. 
     In another embodiment, the antenna switching module  272  may determine the route quality indicator for both the active antenna and one or more inactive antennas, and may compare the route quality indicators. The antenna switching module  272  may then select the antenna associated with the highest route quality indicator. In other words, the antenna switching module  272  may continue using the active antenna when it is associated with the highest route quality indicator, and may switch to another antenna when that antenna is associated with the highest route quality indicator. 
       FIG. 4  is a flowchart  400  depicting an exemplary method of determining a network quality metric. Although the method of flowchart  400  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  400  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  400  may be performed by the network quality module  276  ( FIG. 2 ) in conjunction with one or more of the antenna switching module  272 , the processor  200 , the memory  210 , and the antennas  144 ,  146 , and  250 . Moreover, the blocks in the flowchart  400  may implement at least a portion of the functionality described above with respect to blocks  305  and/or  325  of  FIG. 3 . Although the method of flowchart  400  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  405 , the network quality module  276  selects (or receives) a network route for testing. As discussed above, the network route can include a data path from the wireless device  110  to another device (for example, from the wireless device  110   a  to the wireless device  110   b  discussed above with respect to  FIG. 1 ). For example, the processor  200  may generate a communication (such as videoconference data), and may select a radio and an antenna over which to transmit the communication. The communication may traverse one or more network access points, switches, routers, etc., before reaching a destination device. Accordingly, each network route can be associated with a particular antenna. 
     Next, at block  410 , the network quality module  276  determines whether the selected network route is active. In an embodiment, a network route is active when it is associated with an active antenna. In another embodiment, a network route is active when the wireless device  110  transmits and/or receives data over the route. If the network route is not active, the network quality module  276  may not be capable of determining any network quality metrics for the route. Accordingly, the network quality module  276  can be configured to send a test communication via the network route at block  415 . 
     Referring still to block  415 , in an embodiment, the test communication may include null data. In other words, the test communication may not include data associated with a pre-existing data session. In another embodiment, the test communication can include duplicate data. For example, the test communication can include a portion of data (such as audio and/or video data) also communicated via another network route. If the test communication results in a high quality metric, the antenna switching module  272  can begin transmitting the video portion over the selected antenna. 
     When the network route is active, or when a test communication is sent, the network quality module  276  determines one or more network route metrics. Network route metrics can include, for example, an a one-way network latency, a round-trip time, a packet loss pattern, an available bandwidth, an end-to-end latency, an end-to-end packet loss rate, a jitter of the network route, etc. In various embodiments, the network quality module  276  can determine additional network route metrics known in the art. 
     At block  420 , the network quality module  276  determines an end-to-end latency of the network route. In an embodiment, the network quality module  276  measures the time between transmission of a packet, and the receipt of an acknowledgment or other reply. In various embodiments, the network quality module  276  can receive end-to-end latency data from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive end-to-end latency measurements from another videoconferencing application on the wireless device  110   b.    
     Then, at block  425  the network quality module  276  determines an end-to-end packet loss rate of the network route. In an embodiment, the network quality module  276  can determine the end-to-end packet loss rate by measuring the number of packets sent, and the number of packets acknowledged. In various embodiments, the network quality module  276  can receive end-to-end packet loss rate from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive end-to-end packet loss measurements from another videoconferencing application on the wireless device  110   b.    
     Subsequently, at block  430  the network quality module  276  determines a jitter of the network route. In an embodiment, the network quality module  276  can determine the jitter by measuring the variation in latency measurements. In various embodiments, the network quality module  276  can receive jitter from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive jitter measurements from another videoconferencing application on the wireless device  110   b.    
       FIG. 5  is a flowchart  500  depicting an exemplary method of determining an antenna quality metric. Although the method of flowchart  500  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  500  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  500  may be performed by the antenna quality module  274  ( FIG. 2 ) in conjunction with one or more of the antenna switching module  272 , the processor  200 , the memory  210 , and the antennas  144 ,  146 , and  250 . Moreover, the blocks in the flowchart  500  may implement at least a portion of the functionality described above with respect to blocks  305  and/or  325  of  FIG. 3 . Although the method of flowchart  500  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  505 , the antenna quality module  274  selects (or receives) an antenna for testing. Next, at block  510 , the antenna quality module  274  determines whether the selected antenna is active. If the antenna is not active, the antenna quality module  274  may not be capable of determining any quality metrics for the antenna. Accordingly, the antenna quality module  274  can be configured to send a test communication via the antenna at block  515 . 
     Referring still to block  515 , in an embodiment, the test communication may include null data. In other words, the test communication may not include data associated with a pre-existing data session. In another embodiment, the test communication can include duplicate data. For example, the test communication can include a portion of data (such as audio and/or video data) also communicated via another antenna. In another embodiment, the test communication can include original data. In other words, the test communication can include a portion of a data session not communicated via another antenna. For example, the test communication can include an audio portion of a videoconference session. If the test communication results in a high quality metric, the antenna switching module  272  can begin transmitting the video portion over the selected antenna. 
     When the antenna is active, or when a test communication is sent, the antenna quality module  274  determines one or more antenna metrics. Antenna metrics can include, for example, an SNR, a transmit power level, a received signal strength indication (RSSI), antenna gain, etc. In various embodiments, the antenna quality module  274  can determine additional antenna metrics known in the art. 
     At block  520 , the antenna quality module  274  determines an SNR of the antenna. A high SNR can indicate that a communication rate is possible. In an embodiment, the antenna quality module  274  can determine the SNR by querying the radio interface  220  and/or a baseband function. In various embodiments, the antenna quality module  274  can receive SNR data from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive SNR measurements from another videoconferencing application on the wireless device  110   b.    
     Then, at block  525  the antenna quality module  274  determines a transmit power level of the antenna. A high transmit power level can indicate that the wireless device  110  is far from an access point, or that there is a lot of interference in the transmit channel. In an embodiment, the antenna quality module  274  can determine the transmit power level by querying the radio interface  220  and/or a baseband function. In various embodiments, the antenna quality module  274  can receive transmit power level from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive end-to-end packet loss measurements from another videoconferencing application on the wireless device  110   b.    
     Subsequently, at block  530  the antenna quality module  274  determines a Receive Signal Strength Indicator (RSSI) for the antenna. A high RSSI can indicate that the wireless device  110  is close to an access point. In an embodiment, the antenna quality module  274  can determine the RSSI by querying the radio interface  220  and/or a baseband function. In various embodiments, the antenna quality module  274  can receive a RSSI from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive RSSI measurements from another videoconferencing application on the wireless device  110   b.    
     Thereafter, at block  535  the antenna quality module  274  determines a gain of the antenna. In an embodiment, the antenna quality module  274  can determine the gain by querying the radio interface  220  and/or a baseband function. In various embodiments, the antenna quality module  274  can receive gain from a remote device. For example, a videoconferencing application on the wireless device  110   a  can receive gain measurements from another videoconferencing application on the wireless device  110   b.    
       FIG. 6  is a flowchart  600  depicting an exemplary method of determining a user performance metric. Although the method of flowchart  600  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  600  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  600  may be performed by the user performance module  278  ( FIG. 2 ) in conjunction with one or more of the antenna switching module  272 , the processor  200 , the memory  210 , and the user interface  230 . Moreover, the blocks in the flowchart  600  may implement at least a portion of the functionality described above with respect to blocks  305  and/or  325  of  FIG. 3 . Although the method of flowchart  600  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  605 , the user performance module  278  selects (or receives) an antenna for analysis. Next, at block  610 , the user performance module  278  determines whether there is an existing user preference with respect to the selected antenna. In an embodiment, the wireless device  110  can receive one or more user preferences via the user interface  230 , and the user preferences can be stored in the memory  210 . User preferences can include, for instance, a preference for certain radios and/or associated antennas. A user may prefer that the wireless device  110  use a WiFi radio and/or antenna, as opposed to a UMTS radio and/or antenna, which may incur usage charges from a wireless carrier. 
     At block  615 , if a user preference exists, the user performance module  278  can apply the preference to the user performance metric. For example, if a user prefers to use WiFi over UMTS, the user performance module  278  can increase the user performance metric reported with respect to the WiFi antenna, and decrease the user performance metric reported with respect to the UMTS antenna. In an embodiment, the user performance module  278  can adjust the user performance metric based on a weight or priority associated with each user preference. 
     Then, at block  620 , the user performance module  278  determines whether there is condition associated with the selected antenna that can negatively impact user experience. In an embodiment, the user performance module  278  can measure a CPU load associated with communication via the selected antenna. For example, some radios and/or antennas may require greater processing power, which might affect device responsiveness. The user performance module  278  can also measure a power consumption associated with communication via the selected antenna. For example, some radios and/or antennas may require greater power consumption, which might reduce battery life. In one embodiment, the user performance module  278  can also measure a temperature of the device in order to select an antenna based, at least in part, on thermal design constraints. 
     The user performance module  278  can also measure a device position with respect to the user. For example, the user interface  230  can include a proximity sensor that can detect which the position of one or more antennas with respect to the user&#39;s head. The user performance module  278  can be configured to adjust the user performance metric such that preference is given to antennas away from the user&#39;s head. In various embodiments, the user performance module  278  can monitor one or more of a playback or transmission buffer occupancy, a media playback state (such as paused, playing, stopped, fast forward, etc.), an audio state (such as muted, dropped-out, etc.), etc. In an embodiment, the user performance module  278  can provide audio and/or visual feedback regarding one or more route quality metrics, to the user via the user interface  230 . 
     At block  625 , if a user impact exists, the user performance module  278  can adjust the user performance metric accordingly. For example, if a certain antenna will increase power consumption, the user performance module  278  can reduce the user performance metric associated with that antenna. In an embodiment, the user performance module  278  can adjust the user performance metric based on a weight or priority associated with each type of user impact. Subsequently, at block  630 , the user performance module  278  can report the user performance metric. 
       FIG. 7  is a flowchart  700  depicting an exemplary method of determining a predictive performance metric. Although the method of flowchart  700  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  700  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  700  may be performed by the predictive performance module  280  ( FIG. 2 ) in conjunction with one or more of the antenna switching module  272 , the processor  200 , the memory  210 , and the antennas  144 ,  146 , and  250 . Moreover, the blocks in the flowchart  700  may implement at least a portion of the functionality described above with respect to blocks  305  and/or  325  of  FIG. 3 . Although the method of flowchart  700  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  705 , the predictive performance module  280  selects (or receives) an antenna for analysis. Next, at block  710 , the predictive performance module  280  determines whether there is an existing historical performance record with respect to the selected antenna. Historical performance records can include information correlating one or more situational factors with antenna performance. For example, historical performance records can include information including a timestamp, device location, speed, direction, altitude, battery state, user activity, nearby access points, latency, throughput, jitter, packet loss, SNR, transmit power, antenna gain, RSSI, etc. 
     In an embodiment, the predictive performance module  280  can query the memory  210  to determine whether a record exists with respect to the selected antenna. In an embodiment, historical performance records may include timestamps, and the predictive performance module  280  may only determine that a valid record exists if the record is within a threshold age. 
     At block  715 , if a performance history record exists, the predictive performance module  280  retrieves the record from the memory  210 . Then, at block  720 , the predictive performance module  280  can then determine current conditions and predict performance of the selected antenna based on the current conditions and the performance history data. For example, if WiFi packet loss has historically been high when the wireless device  110  is traveling at 60 mph, and the wireless device  110  is currently travelling at 60 mph, the predictive performance module  280  may predict poor WiFi performance. Accordingly, the predictive performance module  280  may reduce the predictive performance metric for an antenna associated with the WiFi radio. 
     At block  725 , if a performance history record does not exist, the predictive performance module  280  determines current conditions and performance data. In an embodiment, predictive performance module  280  can determine current performance data in conjunction with one or more of the antenna quality module  274 , the network quality module  276 , and the user performance module  278 . Thereafter, at block  730 , the predictive performance module  280  records the performance data in the memory  210 . 
     Subsequently, at block  735 , the predictive performance module  280  reports the predictive performance metric. If there was no existing performance history record, the predictive performance module  280  may report a neutral or null predictive performance metric. In an embodiment, the antenna switching module may not include a neutral or null predictive performance metric when determining the route quality indicator. 
       FIG. 8  is a flowchart  800  depicting an exemplary method of performing pre-activation functions. Although the method of flowchart  800  is described herein with reference to the wireless device  102  discussed above with respect to  FIG. 1 , a person having ordinary skill in the art will appreciate that the method of flowchart  800  may be implemented by another suitable device. In an embodiment, the blocks in the flowchart  800  may be performed by the antenna switching module  272  ( FIG. 2 ) in conjunction with one or more of the radio interface  220 , the processor  200 , the memory  210 , and the antennas  144 ,  146 , and  250 . Moreover, the blocks in the flowchart  800  may implement at least a portion of the functionality described above with respect to block  340  of  FIG. 3 . Although the method of flowchart  800  is described herein with reference to a particular order, in various embodiments, blocks herein may be performed in a different order, or omitted, and additional blocks may be added. 
     First, at block  805 , the antenna switching module  272  analyzes a communication (such as a media stream) to ascertain the likelihood of a disruption during activation of, and switching to, a new antenna. The antenna switching module  272  may determine that there is a relatively high likelihood of disruption when, for example, the bit-rate of the media stream is high compared to the bandwidth available to a network route including the selected antenna. In an embodiment, the antenna switching module  272  can determine a disruption metric indicative of the likelihood of disruption. 
     Next, at block  810 , the antenna switching module  272  can compare the disruption metric to a disruption threshold in order to determine whether the potential for disruption is acceptable. If the likelihood of disruption is acceptable, the antenna switching module  272  can terminate pre-activation functions and proceed to switch antennas at block  345  ( FIG. 3 ). On the other hand, if the antenna switching module  272  determines that the potential for disruption is unacceptable, the antenna switching module  272  can perform one or more pre-activation functions at blocks  815 ,  820 , and  825 . 
     At block  815 , the antenna switching module  272  can pre-fill a transmission queue for the selected antenna and associated radio, if an individual transmission queue is available. In an embodiment, pre-filling the individual transmission queue can reduce packet loss. 
     Then, at block  820 , the antenna switching module  272  can search the media stream for a period of low-entropy in order to determine an acceptable time at which to switch antennas. In various embodiments, the antenna switching module  272  can determine an acceptable time to switch antennas based on one or more of a detected audio silence, a timeout period, a video position and/or frame type, a status of a baseband queue of the candidate antenna, etc. For example, the switching module  272  can look forward a playback buffer, searching for a period of silence, darkness, or low entropy in a media stream. The antenna switching module  272  can time the antenna switch to coincide with the period of silence, darkness, or low entropy, during which a user may be less likely to notice any interruption. 
     In an embodiment, if the antenna switching module  272  does not detect a period of low entropy below an acceptable entropy threshold within a timeout period, the antenna switching module  272  may abort activation of the selected antenna. In another embodiment, if the antenna switching module  272  does not detect a period of low entropy below an acceptable entropy threshold within a timeout period, the antenna switching module  272  can activate the selected antenna (at block  345 ) irrespective of the determined entropy. In yet another embodiment, the antenna switching module  272  may continue to increase the acceptable entropy threshold one or more times after one or more timeout periods, until the antenna switching module  272  detects a period of low entropy below an acceptable entropy threshold. 
     Subsequently, at block  825 , the antenna switching module  272  can reduce a transfer rate (including a frame rate and/or audio bit-rate) during a period leading up to an antenna switch. In an embodiment, reducing the bandwidth requirements of the media stream prior to antenna activation may further reduce potential packet loss. In an embodiment, the antenna switching module  272  can effect a reduction in transfer rate by notifying one or more hardware and/or software components (such as, for example, audio and/or video codecs) of an impending antenna switch. Audio and/or video codecs may respond by reducing a target bit-rate, adjusting a number of key and/or reference frames in the media stream, etc. 
     Thereafter, at block  345 , the antenna switching module  272  can activate the selected antenna. Post-activation, at block  830 , the antenna switching module  272  can resume the original transfer rate, in embodiments where the antenna switching module  272  reduced the transfer rate prior to antenna activation. In various embodiments, the antenna switching module  272  can perform any combination of the aforementioned pre-activation functions. 
     Referring again to  FIG. 2 , in various embodiments, the wireless device  110  may further modify the media stream and/or other device parameters after switching antennas. The wireless device  110  may modify the media stream, for example, to further reduce any potential packet loss or visual degradation after the transition to a new network route. 
     In one embodiment, the wireless device  110  can apply error resilient techniques to an audio, video, and/or other data stream. For example, the wireless device  110  can apply forward error correction (FEC) algorithms to the communications. In another embodiment, the wireless device  110  can adjust the media data rate based on the determined route quality for the new network route and/or antenna configuration. For example, if the new network route includes a higher bandwidth channel than the old network route, the wireless device  110  can increase the bit rate of the media stream. 
     In another embodiment, the wireless device  110  can send one or more refresh signals to audio and/or video generators. This may, for example, cause the audio and/or video generators to insert additional intraframes (I-frames), Long-Term Reference Pictures (LTRP), etc. into the media stream. 
     In another embodiment, the wireless device  110  can continue to transmit over the old antenna for a period of time. Accordingly, the wireless device  110  may transmit duplicate data over two antennas and/or radios for the overlapping time period. 
     In another embodiment, the antenna switching module  272  can be configured with a cool-down period. The cool-down period can be a period of time after switching to a new antenna and/or network route, during which the antenna switching module  272  will not switch antennas and/or network routes again. The cool-down period can be pre-set or dynamic. For example, the cool-down period can increase each time the wireless device  110  switches antennas and/or network routes, subject to a time-decay factor over which the cool-down period will fade back to an initial value. 
     Although the foregoing description discusses network route selection primarily in terms of antenna selection, the present disclosure can be applied to the monitoring and selection of any aspect of the network route including, but not limited to, radios, other wireless communication interfaces, wired communication interfaces, routers, switches, etc. For example, the “antenna” switching module  272  described above with respect to  FIG. 3  can function as a “channel” switching module. In an embodiment, the channel switching module can measure the route quality indicators associated with one or more communication channels, and selecting a new channel. Channels can include, for example, cellular or WiFi channels. 
     The various illustrative logics, logical blocks, modules, circuits and algorithm steps described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and steps described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system. 
     The hardware and data processing apparatus 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 single- or multi-chip 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, or, 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. In some implementations, particular steps and 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, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also can be implemented as one or more computer programs, i.e., one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus. 
     Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. 
     Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a sub combination. 
     Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

Metadata:
Filing Date: 20121029
Publication Date: 20150901
Grant Date: 20150901
Priority Date: 20120229
Inventors: ABUAN JOE S.
ZHOU XIAOSONG
SHIVA SUNDARARAMAN V.
WU HSI-JUNG
YANG YAN
JEONG HYEONKUK
NORMILE JAMES O.
CHUNG CHRIS Y.
GARCIA ROBERTO
JANSEN THOMAS C.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W72/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W40/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W40/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04N7/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L45/306", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L45/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L45/306", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W40/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L45/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W40/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N7/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L45/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W72/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W40/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04N7/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W72/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W40/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L45/306", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 49002427