Patent Publication Number: US-2021185620-A1

Title: Granular adjustment of antenna power in multi-radio systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/381,946, entitled “Granular Adjustment of Antenna Power in Multi-Radio Systems,” filed Apr. 11, 2019, which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/738,224, filed on Sep. 28, 2018, both of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     The present disclosure relates generally to wireless communication systems and, more specifically, to systems and methods for multi-radio systems having multiple antennas. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Certain electronic devices may exchange data and/or form networks using wireless communication systems. For example, laptops, mobile phones, and other similar devices may have wireless network interfaces that can connect to wireless networks. Communication with these networks may be performed using radio signals (e.g., radiofrequency (RF) signals). For safety reasons, limitations in the power of the emitted RF signals may be imposed. For example, the Federal Communications Commission (FCC) specifies a limit to the total amount of radiation emitted, specified as a Specific Absorption Rate (SAR) limit of 1.6 W/kg. This value may specify a total power generated by an antenna of an electronic device. 
     Some of these devices may be capable of connecting to multiple networks, such as cellular networks, wireless Ethernet networks, Bluetooth networks, and others. To connect to the multiple networks, each device may use a shared antenna or multiple antennas located in close proximity to each other. To satisfy the safety limitations on radiation emission (e.g., the SAR limit), the electronic devices may operate by scaling back the power in a first network when the electronic device joins a second network. Thus, such strategies may result in reducing signal quality or communication performance of at least one network (e.g., the first network) to maintain communication using the multiple networks. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     Certain wireless electronic devices (e.g., multi-radio devices) may be capable of joining multiple radiofrequency (RF) networks using a subset of available antennas. In some situations, limits may be enforced to reduce the emitted radiation from an electronic device. As usage of each network may emit radiation, simultaneous connection between the electronic device and multiple networks may employ active power management to satisfy the limits of the emitted radiation. 
     Embodiments described herein are directed to multi-radio devices, and methods of operation thereof, in which the management of the transmission powers is based on the network and/or the antenna location. In some embodiments, the location information may be encoded in messages that distinguish groups (e.g., group-by-group basis management of power). In some embodiments, the location information may be encoded in messages that distinguish individual antennas (e.g., antenna-by-antenna basis management of power). Combination of group-by-group and antenna-by-antenna management may also be employed for different networks. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of a multi-radio electronic device that includes a granular transmission power in a radiofrequency (RF) communication system, in accordance with an embodiments of the present disclosure; 
         FIG. 2  is a perspective view of a notebook computer representing an embodiment of the electronic device of  FIG. 1 ; 
         FIG. 3  is a front view of a hand-held device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 4  is a front view of another hand-held device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 5  is a front view of a desktop computer representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 6  is a front view and side view of a wearable electronic device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 7  is a block diagram of a multi-radio electronic device having multiple antennas and multiple network controllers, in accordance with embodiments of the present disclosure; 
         FIG. 8  is a flow chart for a method that performs granular management of transmission power, in accordance with embodiments of the present disclosure; 
         FIG. 9  is a schematic diagram of a multi-radio electronic device with at least 8 antennas that enable joining at least three types of RF networks, in accordance with embodiments of the present disclosure; 
         FIG. 10  is a schematic diagram of the multi-radio electronic device of  FIG. 9  that implements group-by-group management of transmission power, in accordance with embodiments of the present disclosure; 
         FIG. 11  is a flow chart for a method that performs group-by-group management of transmission power, in accordance with embodiments of the present disclosure; 
         FIG. 12  is a schematic diagram of the multi-radio electronic device of  FIG. 9  that implements antenna-by-antenna and/or group-by-group management of transmission power, in accordance with embodiments of the present disclosure; and 
         FIG. 13  is a flow chart for a method that performs antenna-by-antenna and/or group-by-group management of the transmission power, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     Certain electronic devices may access wireless networks to exchange data with other electronic devices. Multi-radio devices are electronic devices that may connect to multiple wireless networks simultaneously. For example, certain electronic devices may simultaneously connect to multiple wireless networks, which may include cellular networks (e.g., network using 4G standards such as Long Term Evolution or LTE, 5G standards such as New Radio or 5G NR) and/or connectivity networks (e.g., IEEE 802.3 or Wi-Fi, Bluetooth). Each of the connections may employ one or more antennas that establish radio frequency (RF) connections by emitting and/or receiving RF signals. 
     Some of these electronic devices, such as smartphones, wearable devices, or tablets, may be operated close to the human body. For safety reasons, limitations on the amount of radiation emitted by an electronic device may be imposed. For example, certain regulations impose a maximum specific absorption rate (SAR) for electromagnetic power. In multi-radio devices that connect to multiple networks by a shared antenna or multiple antennas, the radiation power associated with each network may have an additive effect on the total radiation emitted. Therefore, in such systems, changes to the power level for one network may accompany a reduction in power level for a second network. As an example, when a cell phone that is connected to Bluetooth network and a cellular network initiates a call, the power used to connect to the cellular network may be increased to improve the call transmission. In this example, in order to obey SAR specifications, the cell phone may reduce the power used to connect to the Bluetooth network. 
     As electronic devices increase in size and/or operate with multiple antennas, the network-based adjustment may be excessively conservative. For example, a large device having two separated antennas located at opposite ends of the device for two different network. Such device may satisfy total radiation limits (e.g., SAR limits) without substantial reduction in the amount of radiation emitted from each antenna. Embodiments describe herein are related to multi-radio electronic devices, and methods of operation thereof, that enable a more granular control of the transmission power. These embodiments may take into account the localization of the antennas as well as the network to perform the power adjustments in a manner that preserves the safety specifications with an improved overall performance. 
     With the foregoing in mind, there are many suitable multi-radio electronic devices that may benefit from the embodiments for granular power control described herein. Turning first to  FIG. 1 , an electronic device  10  according to an embodiment of the present disclosure may include, among other things, one or more processor(s)  12 , memory  14 , nonvolatile storage  16 , a display  18 , input structures  22 , an input/output (I/O) interface  24 , a network interface  26 , and a power source  28 . The various functional blocks shown in  FIG. 1  may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium) or a combination of both hardware and software elements. It should be noted that  FIG. 1  is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in electronic device  10 . 
     By way of example, the electronic device  10  may represent a block diagram of the notebook computer depicted in  FIG. 2 , the handheld device depicted in  FIG. 3 , the handheld device depicted in  FIG. 4 , the desktop computer depicted in  FIG. 5 , the wearable electronic device depicted in  FIG. 6 , or similar devices. It should be noted that the processor(s)  12  and other related items in  FIG. 1  may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, firmware, hardware, or any combination thereof. Furthermore, the data processing circuitry may be a single contained processing module or may be incorporated wholly or partially within any of the other elements within the electronic device  10 . 
     In the electronic device  10  of  FIG. 1 , the processor(s)  12  may be operably coupled with the memory  14  and the nonvolatile storage  16  to perform various algorithms. Such programs or instructions executed by the processor(s)  12  may be stored in any suitable article of manufacture that includes one or more tangible, computer-readable media at least collectively storing the instructions or routines, such as the memory  14  and the nonvolatile storage  16 . The memory  14  and the nonvolatile storage  16  may include any suitable articles of manufacture for storing data and executable instructions, such as random-access memory, read-only memory, rewritable flash memory, hard drives, and optical discs. In addition, programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by the processor(s)  12  to enable the electronic device  10  to provide various functionalities. 
     In certain embodiments, the display  18  may be a liquid crystal display (LCD), which may allow users to view images generated on the electronic device  10 . In some embodiments, the display  18  may include a touch screen, which may allow users to interact with a user interface of the electronic device  10 . Furthermore, it should be appreciated that, in some embodiments, the display  18  may include one or more organic light emitting diode (OLED) displays, or some combination of LCD panels and OLED panels. 
     The input structures  22  of the electronic device  10  may enable a user to interact with the electronic device  10  (e.g., pressing a button to increase or decrease a volume level). The I/O interface  24  may enable electronic device  10  to interface with various other electronic devices, as may the network interface  26 . The network interface  26  may include, for example, one or more interfaces for a personal area network (PAN), such as a Bluetooth network, for a local area network (LAN) or wireless local area network (WLAN), such as an 802.11x Wi-Fi network, and/or for a wide area network (WAN), such as a 3rd generation (3G) cellular network, universal mobile telecommunication system (UMTS), 4th generation (4G) cellular network, long term evolution (LTE) cellular network, or long term evolution license assisted access (LTE-LAA) cellular network, 5th generation (5G) cellular network, and/or 5G New Radio (5G NR) cellular network. The network interface  26  may also include one or more interfaces for, for example, broadband fixed wireless access networks (WiMAX), mobile broadband Wireless networks (mobile WiMAX), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T) and its extension DVB Handheld (DVB-H), ultra-Wideband (UWB), alternating current (AC) power lines, and so forth. For example, network interfaces  26  may be capable of joining multiple networks, and may employ multiple antennas to that end. As further illustrated, the electronic device  10  may include a power source  28 . The power source  28  may include any suitable source of power, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     In certain embodiments, the electronic device  10  may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may include computers that are generally portable (such as laptop, notebook, and tablet computers) as well as computers that are generally used in one place (such as conventional desktop computers, workstations, and/or servers). In certain embodiments, the electronic device  10  in the form of a computer may be a model of a MacBook®, MacBook® Pro, MacBook Air®, iMac®, Mac® mini, or Mac Pro® available from Apple Inc. By way of example, the electronic device  10 , taking the form of a notebook computer  10 A, is illustrated in  FIG. 2  in accordance with one embodiment of the present disclosure. The depicted computer  10 A may include a housing or enclosure  36 , a display  18 , input structures  22 , and ports of an I/O interface  24 . In one embodiment, the input structures  22  (such as a keyboard and/or touchpad) may be used to interact with the computer  10 A, such as to start, control, or operate a GUI or applications running on computer  10 A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface or application interface displayed on display  18 . 
       FIG. 3  depicts a front view of a handheld device  10 B, which represents one embodiment of the electronic device  10 . The handheld device  10 B may represent, for example, a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. By way of example, the handheld device  10 B may be a model of an iPod® or iPhone® available from Apple Inc. of Cupertino, Calif. The handheld device  10 B may include an enclosure  36  to protect interior components from physical damage and to shield them from electromagnetic interference. The enclosure  36  may surround the display  18 . The I/O interfaces  24  may open through the enclosure  36  and may include, for example, an I/O port for a hardwired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc., a universal service bus (USB), or other similar connector and protocol. 
     User input structures  22 , in combination with the display  18 , may allow a user to control the handheld device  10 B. For example, the input structures  22  may activate or deactivate the handheld device  10 B, navigate user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device  10 B. Other input structures  22  may provide volume control, or may toggle between vibrate and ring modes. The input structures  22  may also include a microphone may obtain a user&#39;s voice for various voice-related features, and a speaker may enable audio playback and/or certain phone capabilities. The input structures  22  may also include a headphone input may provide a connection to external speakers and/or headphones. 
       FIG. 4  depicts a front view of another handheld device  10 C, which represents another embodiment of the electronic device  10 . The handheld device  10 C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device  10 C may be a tablet-sized embodiment of the electronic device  10 , which may be, for example, a model of an iPad® available from Apple Inc. of Cupertino, Calif. 
     Turning to  FIG. 5 , a computer  10 D may represent another embodiment of the electronic device  10  of  FIG. 1 . The computer  10 D may be any computer, such as a desktop computer, a server, or a notebook computer, but may also be a standalone media player or video gaming machine. By way of example, the computer  10 D may be an iMac®, a MacBook®, or other similar device by Apple Inc. It should be noted that the computer  10 D may also represent a personal computer (PC) by another manufacturer. A similar enclosure  36  may be provided to protect and enclose internal components of the computer  10 D such as the display  18 . In certain embodiments, a user of the computer  10 D may interact with the computer  10 D using various peripheral input devices  22 , such as the keyboard  22 A or mouse  22 B, which may connect to the computer  10 D. 
     Similarly,  FIG. 6  depicts a wearable electronic device  10 E representing another embodiment of the electronic device  10  of  FIG. 1  that may be configured to operate using the techniques described herein. By way of example, the wearable electronic device  10 E, which may include a wristband  43 , may be an Apple Watch® by Apple, Inc. However, in other embodiments, the wearable electronic device  10 E may include any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. The display  18  of the wearable electronic device  10 E may include a touch screen display  18  (e.g., LCD, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), as well as input structures  22 , which may allow users to interact with a user interface of the wearable electronic device  10 E. 
     With the foregoing in mind, the block diagram  100  of  FIG. 7  illustrates an example of the electronic device  10  that may have a wireless network interface  26 . The illustrated network interface  26  may have multiple antennas  102 ,  104 ,  106 , and  108 . The antennas  102 ,  104 ,  106 , and  108  may be controlled or operated by network controllers  112  and  114 . The network controller  112  may be used to join a network and the network controller  114  may be used to join a different network. In the illustrated example, the network controller  112  may send RF signals via antennas  102 ,  104 ,  106 , and  108  and the network controller may send RF signal via antennas  104  and  108 . 
     Antennas  102  and  104  may belong to a first group of antennas  118  and antennas  106  and  108  may belong to a second group of antennas  120 , based on a location in the electronic device  10 . Two antennas may be placed in a common group if the distance between the antennas is within a threshold distance. For example, a group may include a set of antennas disposed in a specific region of the electronic device  10  (e.g., the top, the bottom, a side, a front end, a back end, a specific edge). In some embodiments, two antennas may belong to the same group if the radiation emitted from the first antenna and the radiation emitted from the second antenna may potentially lead to a superposition radiation that can exceed a SAR threshold. In additional or alternative embodiments, antennas may belong in the same group if the separation (distance) between the antennas is less than a threshold distance (e.g., a minimum distance). The threshold distance may be calculated based on a simulation of the radiation pattern, an analytical calculation of the radiation power, and/or a SAR to peak location separation ratio (SPLSR). The calculation of the threshold distance (e.g., using the SPLSR) may take into account the power emitted by the antennas. As discussed herein, two antennas may have a separation distance that satisfies the SPLSR when the separation distance provides a SPLSR that is in accordance with healthy requirements. Generally, antennas may be assigned to a common group if the use of one of the antennas may require an adjustment in the use of another antenna to satisfy radiation limitations. 
     As discussed above, antennas may be classified as belonging to similar groups based on a joint impact on safety radiation limits. The use of such grouping may allow a more flexible management of the RF power associated with different networks. For example, as discussed above, management of the power of transmission may take place on a network-based level in conventional systems. As an example, in a conventional embodiment similar to the network device  26  of  FIG. 7 , if the power of the network controller  114  is increased to establish a stronger link, the power of network controller  112  may be decreased (e.g., “backed-off”) without regard to the impact of the power of network controller  112  on the total radiation emitted or SAR limits. By contrast, in the network device  26  of  FIG. 7 , network controller  114  may selectively choose using the antenna  104  and the antenna  108 , and network controller  112  may selectively decrease the power based on the grouping, while still limiting radiation emission within SAR limits. 
     The flow chart in  FIG. 8  illustrates a method  111  for granular control of the power of antennas in a device such as, for example, device  10  of  FIG. 7 . Method  111  may have a process block  113 , in which a power of a first antenna of the device  10  may be changed (e.g., increased or decreased). Process block  113  may be triggered as an event. Following process block  113 , in a decision block  115 , the circuitry may determine if the change in the power of a first antenna may, in combination with the other antennas, cause the electronic device to exceed a radiation emission limit. Such determination may be made based in an individual level (e.g., the determination of the impact of the impact of the first antenna on each other antenna) and/or in a group-by-group level (e.g., the determination of the impact of the first antenna on groups of antenna. The determination may be made based on the location of the antenna, a group of the antenna, and/or separation between the antennas. In some embodiments, the determination may be based dynamically (e.g., in processing circuitry). In alternative or additional embodiments, the determination may be performed by employing a look-up table, such as the one exemplified by Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Look-up table for network device 26 of FIG. 7. 
               
            
           
           
               
               
               
               
               
            
               
                 Selection by 
                   
                   
                   
                   
               
               
                 Network 
                 Power for 
                 Power for 
                 Power for 
                 Power for 
               
               
                 Controller 114 
                 Antenna 102 
                 Antenna 104 
                 Antenna 106 
                 Antenna 108 
               
               
                   
               
               
                 Antenna 104 
                 Decreased 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 Antenna 108 
                 Unchanged 
                 Unchanged 
                 Decreased 
                 Decreased 
               
               
                   
               
            
           
         
       
     
     As illustrated in Table 1, when the network controller  114  selects antenna  104 , network controller  112  may decrease the transmission power for antennas  102  and  104 , as they belong to the same group of antennas  118 . The decrease in the transmission power may allow compliance of the electronic device with radiation limit specifications (e.g., SAR limits, SPSLR limits). Due to the use of the grouping discussed above, the transmission power for antennas  106  and  108  may remain unchanged without exceeding safety specifications. Similarly, as illustrated in Table 1, when the network controller  114  selects antenna  108 , network controller  112  may decrease the transmission power for antennas  106  and  108  without changing the transmission power of antennas  102  and  104 . The look-up table may be stored in a memory of the network device  26  (e.g., in the front-end circuitry) or in a memory of the electronic device  10 . In some embodiments, some antennas may have dedicated front-end modules and, in such embodiments, the look-up table may be a distributed look-up table across the distinct front-end modules. For example, antennas  102 ,  104 ,  106 , and  108  may have dedicated power control circuit. In such system, a power control circuit associated with antenna  102  stores a portion of the look-up table corresponding to the first column of Table 1, a power control circuit associated with antenna  104  stores a portion of the look-up table corresponding to the second column of Table 1, a power control circuit associated with antenna  106  stores a portion of the look-up table corresponding to the third column of Table 1, and a power control circuit associated with antenna  108  stores a portion of the look-up table corresponding to the fourth column of Table 1. 
     Commands to the antennas and/or to the transceivers may be transmitted via a communication interface using a wireless power protocol to a power controller. In some embodiments, the communication interface may provide information by providing a message format that includes bits that encode which antenna and/or which group is being activated, as detailed below. In some embodiments, the bits may be provided by extending the number of bits in a Wireless Communication Interface 2 (WCI2) message. A power controller in the network controller (e.g.,  112 ,  114 ), in transceiver circuitry, and/or antenna circuitry may increase or decrease power by receiving the message and responding in accordance to the above-discussed look-up table. In some embodiments, the look-up table may be used to generate the message sent to the transceiver circuitry and/or the antenna (e.g.,  102 ,  104 ,  106 ,  108 ). Management of the power in a particular antenna that is associated with a particular network may be performed by an amplifier in the antenna, an amplifier in the front-end module coupled to the antenna, and/or in the transceiver circuitry coupled to the antenna. 
     Another example of the systems and methods described herein is illustrated with the multi-radio electronic device  10  of  FIG. 9 , illustrated in diagram  121 . The illustrated multi-radio electronic device  10  may be able to connect to at least three different networks. To that end, the multi-radio electronic device  10  may include a cellular network module  122 , a Wi-Fi network module  124 , and/or a Bluetooth module  125 . The multi-radio electronic device  10  may also have multiple antennas that may service different networks and/or bands. For example, antennas  132 ,  134 ,  136 ,  138 ,  140 , and  142  may be used to join a cellular network. Antennas  144  and  146  may be used to access a 5 GHz Wi-Fi network. Antennas  136 ,  140 , and  146  may be used to access a 2.4 GHz Wi-Fi network and/or a Bluetooth network. The electronic device may have dedicated transceivers  148  and  149  used to access the 5 GHz Wi-Fi network. Transceiver  148  may be used to facilitate control of the antenna  144  and transceiver  149  may be used to facilitate control of the antenna  146 . 
     The multi-radio electronic device  10  of  FIG. 9  is illustrated as an example of an embodiment and may represent a mobile phone, a portable media device, a wearable device, a laptop computer, and/or a tablet computer. As such, implementations of embodiments of the multi-radio electronic device  10  may have different dimensions. For example, the multi-radio electronic device may be a wearable device with a dimension of about 30 mm×30 mm or a tablet computer of about 160 mm×250 mm. As such, the above-discussed grouping of antennas that are described in the discussion of the electronic device in  FIGS. 8, 9, and 11  are illustrative and are provided herein to discuss the implementation of the selective power adjustment described herein. 
     In the descriptions of  FIGS. 9, 10, 11, and 12 , the described adjustments to the power in the antennas are performed in response to changes in the power of antennas used to join cellular networks. Embodiments in which the adjustments are performed in response to changes in power of antennas used to join other networks may be implemented based on the disclosures described herein. It should also be noted that, in some embodiments, the presently disclosed electronic devices  10  may include multi-band cellular devices (i.e., the devices may be capable of joining cellular networks in multiple bands). For example, certain devices may be capable of joining networks in multiple cellular bands such as 380 MHz, 410 MHz, 450 MHz, 480 MHz, 700 MHz, 710 MHz, 750 MHz, 800 MHz, 810 MHz, 850 MHz, 900 MHz, 1,500 MHz, 1,700 MHz, 1,800 MHz, 1,900 MHz, 2100 MHz, 2600 MHz, or 3500 MHz bands. In such multi-band cellular devices, certain antennas may be dedicated or optimized to a subset of all the available bands. As a result, the change in the power of a particular cellular antenna may be performed in response to the band of the network being joined. Similarly, certain devices may be capable of joining Wi-Fi networks using the 2.4 GHz band or the 5 GHz band, and the antennas used to perform Wi-Fi operations may be chosen based on the type of connection band (e.g., the 2.4 GHz band or the 5 GHz band). 
     As discussed above, the transmission power for antennas and/or connecting to associated networks may be adjusted in response to changes in the transmission power of a cellular antenna. The antennas and network connections of the multi-radio electronic device  10  may be controlled at a group level, as illustrated in the diagram  160  of  FIG. 10 . In particular, the electronic device  10  of  FIG. 10  may have antennas arranged in a manner similar to the electronic device  10  of  FIG. 9 . The antennas  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 , and  146  in the electronic device  10  of  FIG. 10  may be assigned to two groups: an upper antenna group  162  near the top  152  of the electronic device  10  and a lower antenna group  164  near a bottom  154  of the electronic device  10 . The upper antenna group  162  may include antennas  138 ,  140 ,  142 , and  144  and the lower antenna group  164  may include antennas  132 ,  134 ,  136 , and  146 . In some embodiments of the multi-radio electronic device  10 , such as a cell phone embodiment, the upper antenna group  162  may be located near the forehead a user holding the cell phone and the lower antenna group  164  may be located near the chin of the user. 
     In order to address the groups, antennas may be assigned to ports. Ports may be used to distinguish location and network capability for an antenna. The multi-radio electronic device  10  of  FIG. 10  may have ports  172 ,  174 ,  176 , and  178 . Port  172  may control antennas  138  and  142  in the upper antenna group  162  that are only used for joining cellular networks and port  174  may control antennas  132  and  134  in the lower antenna group  164  that are only used for joining cellular networks. Port  176  may control the antenna  140  in the upper antenna group  162  that may be used for joining cellular networks, Bluetooth networks, and/or 2.4 GHz Wi-Fi networks. Port  178  may control the antenna  136  in the lower antenna group  164  that may be used for joining cellular networks, Bluetooth networks, and/or 2.4 GHz Wi-Fi networks. As the antennas are divided in two groups  162  and  164 , the message indicating the location of an antenna may be encoded using a single bit. In some embodiments, the antenna location message may be provided by employing WCI2 protocol with one extra bit. More generally, an embodiment that includes N groups may employ a message encoded using an integer number of bits greater or equal to log 2  N. These bits may be added to a WCI2 message. 
     As discussed above, the antennas may be managed on a group level based on a joint impact on safety radiation limits. The use of such grouping may allow a more flexible management of the RF power associated with different networks. As such, an increase to the power of one antenna of the upper antenna group  162  may be accompanied by reduction in the transmission power (e.g. “backing-off”) of other antennas in the upper antenna group  162 . By contrast, an increase to the power of an antenna of the antenna group  162  does not necessarily need to be accompanied by a reduction in the transmission power of antennas in the lower antenna group  164 , as a separation between the antennas may satisfy limits (e.g., SAR limits, SPSLR ratio). The flowchart of  FIG. 11  illustrates a method  180  to adjust the power of the antennas associated with Wi-Fi operations based on a change to the power of an antenna used in a cellular connection, to satisfy the above-discussed criteria. The method  180  of  FIG. 11  is described in association with the diagram  160  of  FIG. 10  and look-up tables described in Tables 2 and 3. 
     Method  180  may be performed iteratively in response to an event  182  associated with a change in the connection state of the cell. The event  182  may be triggered by cell phone events such as an initiation of a call, transmission or reception of a message over cellular network, changes in the connected cellular connection tower, and/or changes in the cellular band. In decision block  184 , the location or the group of the antenna associated with the change in event  182  is determined. If the adjusted cellular antenna is in the upper antenna (“UAT”) group  162  (e.g., antennas  138 ,  140 , and/or  142 ), branch  186  may be applied. If the adjusted cellular antenna is in the lower antenna (“LAT”) group  164  (e.g., antennas  132 ,  134 , and  135 ), branch  188  may be followed. This decision may be implemented by using a bit in the message (e.g., a WCI2 message with an additional bit). For example, in some embodiments, group  162  may be associated with a bit  0  and group  164  may be associated with bit  1 . 
     In branch  186 , the decision block  190  may be followed to determine whether the band of the Wi-Fi connection is a 2.4 GHz band or a 5 GHz band. In some embodiments, the 5 GHz band may be used when the Bluetooth connection is active. If the 5 GHz is not used and, thus, the 2.4 GHz connection is used, antennas that may cause the total radiation to exceed the radiation limits may be scaled back. A look-up table, such as Table 2 may be used in process block  192  to determine which antennas should be scaled back and which antennas should have their power preserved (as opposed to more conventional techniques of scaling back power to all other antennas). If the 5 GHz is used, antennas that may cause the total radiation to exceed the radiation limits may be scaled back. A look-up table such as Table 3 may be used in process block  194  to determine which antennas should be scaled back and which antennas should have their power preserved (as opposed to more conventional techniques of scaling back power to all other antennas). Similarly, in branch  188 , the decision block  196  may be followed to determine whether the band of the Wi-Fi connection is a 2.4 GHz band or a 5 GHz band. If the 2.4 GHz connection is used, a look-up table based on Table 2 may be used in process block  198 . If the 5 GHz is used, a look-up table based on Table 3 may be used in process block  200 . 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Look-up table for 2.4 GHz Wi-Fi, as 
               
               
                 described in method 180 of FIG. 11. 
               
            
           
           
               
               
               
               
            
               
                 Activated 
                 Wi-Fi 
                 Wi-Fi 
                 Wi-Fi 
               
               
                 Group 
                 Power for 
                 Power for 
                 Power for 
               
               
                 Message 
                 Antenna 140 
                 Antenna 136 
                 Antenna 146 
               
               
                   
               
               
                 Increase in UAT 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 Group 162 
               
               
                 Increase in LAT 
                 Unchanged 
                 Decreased 
                 Decreased 
               
               
                 Group 164 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Look-up table for 5 GHz Wi-Fi, as 
               
               
                 described in method 180 of FIG. 11. 
               
            
           
           
               
               
               
               
            
               
                   
                 Activated 
                   
                   
               
               
                   
                 Group 
                 Power for 
                 Power for 
               
               
                   
                 Message 
                 Antenna 146 
                 Antenna 144 
               
               
                   
                   
               
               
                   
                 Increase in UAT 
                 Unchanged 
                 Decreased 
               
               
                   
                 Group 162 
               
               
                   
                 Increase in LAT 
                 Decreased 
                 Unchanged 
               
               
                   
                 Group 164 
               
               
                   
                   
               
            
           
         
       
     
     In some embodiments, the control of transmission power of the antennas may be achieved in a more granular level, by controlling the transmission power of the antennas individually. An embodiment of multi-radio electronic device  10  that enables single-antenna controllable transmission power level is illustrated in diagram  220  of  FIG. 12 . The electronic device  10  of  FIG. 12  may have antennas and Wi-Fi modules arranged in a manner similar to the electronic device  10  of  FIG. 9 . In the embodiment illustrated in diagram  220 , cellular connections may employ any of the 6 antennas  132 ,  134 ,  136 ,  138 ,  140 , and  142 . As such, encoding of the antenna location message may employ three bits. More generally, an embodiment that include N antennas may employ a message encoded using an integer number of bits greater or equal to log 2  N. 
     As discussed above, the transmission power of the antennas may be managed on a granular level based on joint impact of antennas on safety radiation limits. The use of such grouping may allow a more flexible management of the RF power associated with different networks. As such, an increase to the power of an antenna may be accompanied by reduction in the transmission power (e.g. “backing-off”) in antennas that may cause a joint transmission that may cause the total transmission of the device to exceed radiation limits. However, an increase to the power of an antenna does not necessarily need to be accompanied by a reduction in the transmission power of antennas that are sufficiently separated and, thus, satisfy limits (e.g., SPSLR ratio). The flowchart of  FIG. 13  illustrates a method  240  to adjust the power of the antennas associated with Wi-Fi operations based on a change to the power of an antenna used in a cellular connection, as discussed above. The method  240  of  FIG. 13  is described in association with the diagram  220  of  FIG. 12  and look-up tables described in Tables 4 and 5. 
     Method  240  of  FIG. 13  may be performed iteratively in response to an event  242  associated with a change in the connection state of the cell. The event  242  may be triggered by cell phone events such as an initiation of a call, transmission or reception of a message over cellular network, changes in the connected cellular connection tower, and/or changes in the cellular band. In decision block  224 , the antenna associated with the change in event  242  is determined. In the example, antenna  140  is associated with branch  246 A, antenna  142  is associated with branch  246 B, antenna  138  is associated with branch  246 C, antenna  136  is associated with branch  246 D, antenna  134  is associated with branch  246 E, and antenna  132  may be associated with branch  246 F. Each branch may cause the Wi-Fi antennas to respond in accordance with a look-up table such as that of Table 4 or Table 5. Look-up tables such as Table 4 and Table 5 may be used in process blocks  248 A-E to determine which antennas should be scaled back and which antennas should have their power preserved (as opposed to more conventional techniques of scaling back power to all other antennas). This decision may be implemented by verifying the additional three bits in the message (e.g., a WCI2 message with three additional bits). For example, antenna  138  may be associated with bits  001 , antenna  140  may be associated with bits  010 , antenna  142  may be associated with bit  011 , antenna  132  may be associated with bits  100 , antenna  136  may be associated with bits  101 , and antenna  134  may be associated with bits  110 . 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Look-up table for 2.4 GHz Wi-Fi, as 
               
               
                 described in method 240 of FIG. 13. 
               
            
           
           
               
               
               
               
            
               
                 Activated 
                 Wi-Fi 
                 Wi-Fi 
                 Wi-Fi 
               
               
                 Antenna 
                 Power for 
                 Power for 
                 Power for 
               
               
                 Message 
                 Antenna 140 
                 Antenna 136 
                 Antenna 146 
               
               
                   
               
               
                 UAT Antenna 3 (138) 
                 Unchanged 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4A (140) 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4B (142) 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 LAT Antenna 1 (132) 
                 Unchanged 
                 Unchanged 
                 Unchanged 
               
               
                 LAT Antenna 2A (136) 
                 Unchanged 
                 Decreased 
                 Decreased 
               
               
                 LAT Antenna 2B (134) 
                 Unchanged 
                 Decreased 
                 Decreased 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Look-up table for 5 GHz Wi-Fi, as 
               
               
                 described in method 240 of FIG. 13. 
               
            
           
           
               
               
               
               
            
               
                   
                 Activated 
                   
                   
               
               
                   
                 Antenna 
                 Power for 
                 Power for 
               
               
                   
                 Message 
                 Antenna 146 
                 Antenna 144 
               
               
                   
                   
               
               
                   
                 UAT Antenna 3 (138) 
                 Unchanged 
                 Decreased 
               
               
                   
                 UAT Antenna 4A (140) 
                 Unchanged 
                 Unchanged 
               
               
                   
                 UAT Antenna 4B (142) 
                 Unchanged 
                 Unchanged 
               
               
                   
                 LAT Antenna 1 (132) 
                 Unchanged 
                 Unchanged 
               
               
                   
                 LAT Antenna 2A (136) 
                 Decreased 
                 Unchanged 
               
               
                   
                 LAT Antenna 2B (134) 
                 Unchanged 
                 Unchanged 
               
               
                   
                   
               
            
           
         
       
     
     In some embodiments, a combined approach may be used for granular adjustment. For example, a three-network device may have one network circuitry respond to a change in a second network circuitry in an antenna-by-antenna basis and have a third network circuitry respond to the change in the second network circuitry in a group-by-group basis. For example, the method  240  of  FIG. 13  may be adapted to perform adjustments to the power of antennas associated with Bluetooth operations based on the state of the antennas used in a cellular connection and Wi-Fi connection, in order to satisfy limits for total radiation. An example of a lookup table for Bluetooth circuitry is represented in Table 6. A look-up table such as Table 6 may be used in process block  252 A-B to determine which antennas should be scaled back and which antennas should have their power preserved (as opposed to more conventional techniques of scaling back power to all other antennas). The Bluetooth operation may be performed during a process block  252 A, following block processes  248 A,  248 B, or  248 C or during a process block  252 B, and following block processes  248 D,  248 E, or  248 F which may take place in a group-by group basis. The Bluetooth circuitry may extract the antenna information from the three additional bits, as discussed above. Moreover, the management of power for Bluetooth operations may be performed by employing ports (e.g., ports  172 ,  174 ,  176 , and  178 ), as discussed above. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Look-up table for Bluetooth, as described in method 240 of FIG. 13. 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Wi-Fi 
                   
                   
                   
               
               
                 Activated Cellular 
                 5 GHz 
                 BT Power for 
                 BT Power for 
                 BT Power for 
               
               
                 Antenna Message 
                 State 
                 Antenna 140 
                 Antenna 136 
                 Antenna 146 
               
               
                   
               
               
                 UAT Antenna 3 (138) 
                 On 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4A (140) 
                 On 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4B (142) 
                 On 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 LAT Antenna 1 (132) 
                 On 
                 Unchanged 
                 Decreased 1   
                 Decreased 1   
               
               
                 LAT Antenna 2A (136) 
                 On 
                 Unchanged 
                 Decreased 1   
                 Decreased 1   
               
               
                 LAT Antenna 2B (134) 
                 On 
                 Unchanged 
                 Decreased 1   
                 Decreased 1   
               
               
                 UAT Antenna 3 (138) 
                 On 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4A (140) 
                 Off 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 UAT Antenna 4B (142) 
                 Off 
                 Decreased 
                 Unchanged 
                 Unchanged 
               
               
                 LAT Antenna 1 (132) 
                 Off 
                 Unchanged 
                 Decreased 2   
                 Decreased 2   
               
               
                 LAT Antenna 2A (136) 
                 Off 
                 Unchanged 
                 Decreased 2   
                 Decreased 2   
               
               
                 LAT Antenna 2B (134) 
                 Off 
                 Unchanged 
                 Decreased 2   
                 Decreased 2   
               
               
                   
               
               
                   1, 2 The decrease when the 5 GHz antenna is high, indicated by superscript 1 may be higher than the decrease when the 5 GHz is low, indicated by superscript 2. 
               
            
           
         
       
     
     A look-up table may cause distinct amounts of decrease in the Bluetooth power for certain antennas based on the state of other antennas. This is exemplified in Table 6. The Bluetooth power for antennas  136  and/or  146  may be decreased by a lesser amount when the 5 GHz antenna is off (e.g., Wi-Fi connection is off, Wi-Fi network is configured to employ 2.4 GHz) than when the 5 GHz antenna is on. This may be a response to the fact that the antenna  146  can be used to transmit 5 GHz as well as Bluetooth and/or that the antenna  146  that may be close to the antenna  136 . 
     In the disclosed embodiments, reference is made to reductions in the power of transmission. The specific reduction employed may be a function of an SAR calculation or a SPLSR calculation, as discussed above. The reduction in power may be, for example, a reduction by 1 decibel (dB), 3 dB, 5 dB, 7 dB, 9 dB, 15 dB, or 20 dB in the transmission power. The granularity in the management of transmission power discussed above may increase the quality in connection during simultaneous connection to multiple networks, particularly when compared to more conventional methods of scaling back power to other antennas or network connections without considering the impact of the other antennas or network connections on the total radiation emitted or SAR limits. For example, in the group-by-group management illustrated in Tables 2 and 3, the reduction in the transmission power for Wi-Fi operations may reach, on average, 50% of the available antennas. In the antenna-by-antenna management illustrated in Table 4, the reduction in the transmission power for Wi-Fi operation may reach, on average 72% of the available antennas, and in the antenna-by-antenna management illustrated in Table 5, the reduction in the transmission power for Wi-Fi operations may reach, on average, 87% of the available antennas. The increased antenna availability may reduce the number of dropped packets, increase signal-to-noise ratio, and provide improved bandwidth. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. For example, the methods may be applied for embodiments having different numbers and/or locations for antennas, different groupings, and/or different networks. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).