PATENT DOCUMENT

Publication Number: US-9560601-B2
Application Number: US-201514641145-A
Country: US
Kind Code: B2

Title: Radio frequency system power back off systems and methods

Abstract:
Systems and method for improving design and/or operation of a radio frequency system are provided. One embodiment provides a radio frequency system, which includes a first look-up table that describes a static reference value, association between a maximum output power and a first specification level, and association between a first back off value and a second specification level, in which the first back off value is defined in relation to the static reference value and used to determine a first reduced output power; and a second look-up table that describes association between the maximum output power and a first set of operational parameters and association between the first reduced output power and a second set of operational parameters. The radio frequency system wirelessly transmits the analog electrical signal in compliance with an instructed specification level instruction by determining a desired output power based on the instructed specification level using the first look-up table and implementing operational parameters determined based on the desired output power using the second look-up table.

Claims:
What is claimed is: 
     
       1. A radio frequency system configured to wirelessly transmit an analog electrical signal, wherein the radio frequency system comprises:
 a first look-up table configured to describe a static reference value, association between a maximum output power and a first specification level, and association between a first back off value and a second specification level, wherein the first back off value is defined in relation to the static reference value and used to determine a first reduced output power; and 
 a second look-up table configured to describe association between the maximum output power and a first set of operational parameters and to describe association between the first reduced output power and a second set of operational parameters; 
 wherein the radio frequency system is configured to wirelessly transmit the analog electrical signal in compliance with an instructed specification level instruction from a supervisory entity by:
 determining a desired output power of the analog electrical signal based on the instructed specification level using the first look-up table; and 
 implementing operational parameters determined based on the desired output power using the second look-up table. 
 
 
     
     
       2. The radio frequency system of  claim 1 , wherein the first look-up table is a network signaling value look-up table configured to describe association between the maximum output power and a first network signaling value and to describe association between the first back off value and a second network signaling value, wherein the first network signaling value and the second network signaling value comprise different standards regarding allowable spurious emissions transmitted in the analog electrical signal. 
     
     
       3. The radio frequency system of  claim 1 , wherein the second look-up table is an operational parameters look-up table and the first set of operational parameters and the second set of operational parameters comprise position of filter rejection by a filter, aggressiveness of filter rejection by the filter, amplification by an amplifier component, or any combination thereof. 
     
     
       4. The radio frequency system of  claim 1 , wherein the first look-up table is configured to describe association between a second back off value and a third specification level, wherein the second back off value is defined in relation to the static reference value and used to determine a second reduced output power and the second look-up table is configured to describe association between the second reduced output power and a third set of operational parameters. 
     
     
       5. The radio frequency system of  claim 1 , wherein the radio frequency system is configured to determine the desired output power by determining that the desired output power is the maximum output power when the first specification level is received and that the desired output is the first reduced output power when the second specification level is received, wherein the first reduced output power is determined by subtracting the first back off value from the static reference value. 
     
     
       6. The radio frequency system of  claim 1 , wherein the radio frequency system is configured to determine the desired output power by determining that the desired output power is a lesser of the maximum output power and the first reduced output power when the second specification level is received. 
     
     
       7. The radio frequency system of  claim 1 , wherein the radio frequency system is configured to implement the operation parameters by instructing a filter and an amplifier component to adjust operation. 
     
     
       8. The radio frequency system of  claim 1 , wherein the static reference value is different from the maximum output power. 
     
     
       9. The radio frequency system of  claim 8 , wherein the static reference value is 23 dBm. 
     
     
       10. The radio frequency system of  claim 1 , the first specification level is a first network signaling value and the second specification level is a second network signaling value. 
     
     
       11. The radio frequency system of  claim 1 , wherein the first specification level is a network signaling value of NS_ 01  and the second specification level is a network signaling value of NS_ 12 , NS_ 13 , or NS_ 15 . 
     
     
       12. A tangible, non-transitory, computer-readable medium configured to store instructions executable by a processor of a radio frequency system, wherein the instructions comprise instructions to:
 determine, using the processor, a network signaling value received from a supervisory entity; 
 determine, using the processor, a desired output power of the radio frequency system by inputting the network signaling value into a network signaling value look-up table, wherein the network signaling value look-up table associates the network signaling value to a back off value defined in relation to a static reference value different from a maximum output power of the radio frequency system; 
 determine, using the processor, a set of operational parameters associated with the desired output power by inputting the desired output power into an operational parameters look-up table, wherein the operational parameters look-up table associates sets of operational parameters with various output powers; and 
 instruct, using the processor, the radio frequency system to transmit analog electrical signals at the desired output power and in compliance with the network signaling value by implementing the set of operational parameters. 
 
     
     
       13. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the instructions to determine the desired output power comprise instructions to subtract the back off value from the static reference value. 
     
     
       14. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the instructions to determine the desired output power comprise instructions to determine that the desired output power is a lesser of the maximum output power and the static reference value minus the back off value. 
     
     
       15. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the operational parameters comprise position of filter rejection by a filter, aggressiveness of filter rejection by the filter, amplification by an amplifier component, or any combination thereof. 
     
     
       16. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the static reference value is 23 dBm. 
     
     
       17. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the supervisory entity is a wireless carrier. 
     
     
       18. The tangible, non-transitory, computer readable medium of  claim 12 , wherein the network signaling value comprises standards on allowable spurious emissions and allowable out of band emissions transmitted in the analog electrical signals. 
     
     
       19. A method for designing a radio frequency system, comprising:
 determining, using a processor, standards associated with a plurality of network signaling values, wherein each of the plurality of network signaling values describes a different standard to meet when wirelessly transmitting analog electrical signals from the radio frequency system; 
 determining, using the processor, a maximum output power based at least in part on a first one of the plurality of network signaling values; 
 determining, using the processor, a static reference value different from the maximum output power; 
 determining, using the processor, a first back off value based at least in part on a second one of the plurality of network signaling values to enable determining a first reduced output power using the first back off value and the static reference value; 
 storing, using the processor, a network signaling value look-up table in the radio frequency system such that the network signaling value look-up table associates the maximum output power with the first one of the plurality of network signaling values and associates the first back off value with the second one of the plurality of network signaling values; 
 determining, using the processor, a first set of operational parameters that when implemented in the radio frequency system transmits the analog electrical signals at the maximum output power in compliance with the first one of the plurality of network signaling values and a second set of operational parameters that when implemented in the radio frequency system transmits the analog electrical signals at the first reduced output power in compliance with the second one of the plurality of network signaling values; and 
 storing, using the processor, an operational parameters look-up table in the radio frequency system such that the operational parameters look-up table associates the first set of operation parameters with the maximum output power and associates the second set of operational parameters with the first reduced output power. 
 
     
     
       20. The method of  claim 19 , comprising:
 determining, using the processor, a second back off value based at least in part on a third one of the plurality of network signaling values to enable determining a second reduced output power using the second back off value and the static reference value, wherein the network signaling value look-up table associates the second back off value with the third one of the plurality of network signaling values; and 
 determining, using the processor, a third set of operational parameters that when implemented in the radio frequency system transmits the analog electrical signals at the second reduced output power in compliance with the third one of the plurality of network signaling values, wherein the operational parameters look-up table associates the third set of operational parameters with the second reduced output power. 
 
     
     
       21. The method of  claim 19 , wherein the second one of the plurality of network signaling values comprises a maximum back off from the maximum output power to achieve the second one of the plurality of network signaling values, wherein the first back off value is less than or equal to the maximum back off from the maximum output power. 
     
     
       22. The method of  claim 19 , wherein the first and the second sets of operational parameters comprise a position of filter rejection by a filter, aggressiveness of filter rejection by the filter, amplification by an amplifier component, or any combination thereof. 
     
     
       23. The method of  claim 19 , wherein the first one of the plurality of network signaling values is NS_ 01 . 
     
     
       24. An electronic device comprising:
 an antenna configured to wirelessly transmit data from the electronic device to a network as modulated radio waves and to receive a network signaling value from a supervisory entity of the network; 
 a transceiver configured to generate an analog representation of the data as an analog electrical signal and to generate a digital representation of the network signaling value; 
 an amplifier component configured to amplify the analog electrical signal to a desired output power by generating an amplified analog electrical signal; 
 a filter configured to filter the amplified analog electrical signal to remove noise introduced by the transceiver and the amplifier component by generating a filtered analog electrical signal; and 
 a controller configured to determine the desired output power based on the network signaling value and to instruct the amplifier component and the filter to implement operational parameters associated with the desired output power, wherein determining the desired output power comprises determining a static reference value different from a maximum output power of transmitted analog electrical signals and determining a back off value defined in relation to the static reference value. 
 
     
     
       25. The electronic device of  claim 24 , wherein the controller is configured to instruct the amplifier component to adjust amplification of the analog electrical signal and to instruct the filter to adjust position of filter rejection, aggressiveness of the filter rejection, or both applied to the amplified analog electrical signal. 
     
     
       26. The electronic device of  claim 24 , wherein the antenna is configured to wirelessly transmit the data as modulated radio waves in compliance with the network signaling value. 
     
     
       27. The electronic device of  claim 24 , wherein the electronic device comprises a portable phone, a media player, a personal data organizer, a handheld game platform, a tablet device, a computer, or any combination thereof. 
     
     
       28. The electronic device of  claim 24 , wherein the controller is configured to determine the back off value using a network signaling value look-up table that associates the network signaling value with the back off value and to determine the operational parameters using an operational parameters look-up table that associates the desired output power with the operational parameters.

Description:
BACKGROUND 
     The present disclosure relates generally to radio frequency systems and, more particularly, to output power back off in a radio frequency system. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, 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. 
     Many electronic devices may include a radio frequency system to facilitate wireless communication of data with another electronic device and/or a network. The radio frequency system may include a transceiver that outputs an analog representation of data desired to be wirelessly transmitted as an analog electrical signal. An amplifier component may then amplify the analog electrical signal to a desired output power and one or more filters may filter the amplified analog electrical signal to remove noise. The radio frequency system may then wirelessly transmit the filtered analog electrical signal via an antenna at a desired transmission radio frequency or range of frequencies. 
     Generally, standardization bodies may set standards and regulatory bodies may set regulations regarding wireless transmission by radio frequency systems. For example, the Federal Communications Commission (FCC) in the United States sets regulations on allowable spurious emissions transmitted by radio frequency systems, particularly in protected or restricted frequency bands. Additionally, the 3rd Generation Partnership Project (3GPP) sets standards on allowable out of band emissions at frequencies adjacent the transmission frequency and allowable spurious emissions at frequencies outside of the adjacent frequencies. In fact, the 3rd Generation Partnership Project provides multiple standard levels (e.g., network signaling values) that each sets varying standard on allowable out of band emissions and/or spurious emissions. 
     As such, a supervisory entity of a network, such as a wireless carrier, may instruct a connected radio frequency system to adhere to a particular specification level (e.g., regulation level or standard level). To facilitate meeting the specification level, the radio frequency system may adjust output power from a maximum output power to a reduced output power. However, since the maximum output power may be dynamic, relationship between the maximum output power and the reduced output power may vary. 
     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. 
     The present disclosure generally relates to improving design and/or operation of a radio frequency system. Generally, a supervisory entity of a network may instruct a radio frequency system to communicate with the network in compliance with set specifications (e.g., regulations and/or standards). The specifications may govern the quantity of out of band emissions and/or spurious emissions that are permitted to be transmitted onto the network. In some embodiments, the supervisory entity may send a specification level (e.g., network signaling value) informing the radio frequency system of the specifications that should be complied with when transmitting analog electrical signals. For example, the supervisory entity may send a network signaling value of NS_ 01  to instruct the radio frequency system to be in compliance with a first set of specifications, a network signaling value of NS_ 14  to instruct the radio frequency system to be in compliance with a second set of specifications, and a network signaling value of NS_ 15  to instruct the radio frequency system to be in compliance with a third set of specifications. 
     The present disclosure describes a radio frequency system that operates in compliance with an instructed specification levels (e.g., standard level or regulation level) by adjusting output power used to transmit analog electrical signals. More specifically, to facilitate compliance with an instructed specification level (e.g., network signaling value), the radio frequency system may implement a set of operational parameters that enables the radio frequency system to transmit an analog electrical signal at either a maximum output power or at a reduced output power. For example, the radio frequency system may implement a first set of operational parameters enabling transmission at the maximum output power when a network signaling value NS_ 01  is received, a second set of operational parameters enabling transmission at a first reduced output power when a network signaling value of NS_ 14  is received, and a third set of operational parameters enabling transmission at a second reduced output power when a network signaling value of NS_ 15  is received. 
     In some instances, the maximum output power of the radio frequency system may be adjusted (e.g., increased or decreased) based on various factors, such as various specifications (e.g., standards and/or regulations), power consumption, efficiency, and/or antenna performance. Thus, to improve the design process of the radio frequency system, the reduced output powers may be determined based on back off values in reference to a static reference value, which may vary from the maximum output power. In this manner, adjustments to the one or more reduced output powers may be obviated when the maximum output power is adjusted, thereby reducing a redesign process for the radio frequency system. 
     Moreover, in operation, the performance of the radio frequency system when transmitting analog electrical signals at a reduced output power may be improved. For example, when a particular specification level (e.g., network signaling value) is received, the radio frequency system may determine a reduced output power based on a back off value in reference to the static reference value. In some embodiments, the back off value may be determined via a first look-up table (e.g., a NS_XX LUT). The radio frequency system may then implement operational parameters associated with the reduced output power. In some embodiments, the associated operational parameters may be determined via a second look-up table (e.g., operational parameters LUT). In this manner, the radio frequency system may then transmit analog electrical signals at the reduced output power in compliance with the instructed specification level. Additionally, since the reduced output power is determined relatively independent from the maximum output power, the radio frequency may operate with improved transmission reliability (e.g., higher output power with reduced margin from the specifications). 
    
    
     
       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 electronic device with a radio frequency system, in accordance with an embodiment; 
         FIG. 2  is an example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 3  is an example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 4  is an example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 5  is block diagram of a portion of the radio frequency system of  FIG. 1 , in accordance with an embodiment; 
         FIG. 6  is a block diagram of a controller in the radio frequency system of  FIG. 5 , in accordance with an embodiment; 
         FIG. 7  is a flow diagram describing a process for wirelessly transmitting analog electrical signals using the radio frequency system of  FIG. 5 , in accordance with an embodiment; and 
         FIG. 8  is a flow diagram describing a process for designing the radio frequency system of  FIG. 5 , in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be 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 may nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     As mentioned above, an electronic device may include a radio frequency system to facilitate wirelessly communicating data with another electronic device and/or a network. More specifically, the radio frequency system may modulate radio waves to enable the electronic device to communicate via a personal area network (e.g., Bluetooth network), a local area network (e.g., an 802.11x Wi-Fi network), and/or a wide area network (e.g., a 4 G or LTE cellular network). In other words, the radio frequency systems may utilize various wireless communication protocols to facilitate communication of data. 
     Nevertheless, radio frequency systems may generally be operationally similar regardless of the wireless communication protocol used. For example, to transmit data, processing circuitry may generate a digital representation of the data as a digital electrical signal and a transceiver (e.g., a transmitter and/or a receiver) may then convert the digital electrical signal into one or more analog electrical signals. The analog electrical signals may be wirelessly transmitted at a specific output powers via an antenna based on various factors, such as communication protocol, distance, supervisory entity instructions, instructed specification levels (e.g., standard level or regulation level), and the like. 
     To help illustrate, in a long-term evolution (LTE) context, a wireless carrier (e.g., acting as a supervisory entity) may instruct a radio frequency system to communicate with the network in compliance with a particular network signaling value (e.g., specification level). More specifically, the 3rd Generation Partnership Project (3GPP) sets multiple network signaling values (NS_XX) which each includes standards on allowable out of band emissions at frequencies adjacent a transmission frequency and/or allowable spurious emissions at frequencies outside of the adjacent frequencies. As such, during operation, the wireless carrier may instruct the radio frequency system to communicate with the network in compliance with standards set out in one of the network signaling values (e.g., NS_ 01 , NS_ 12 , NS_ 13 , or NS_ 15 ). 
     Generally, each specification level (e.g., network signaling value) has varying strictness. For example, in the LTE context, NS_ 01  may provide a spurious emissions limit of −36 dBm, NS_ 12  may provide a spurious emissions limit of −42 dBm, NS_ 13  may provide a spurious emissions limit of −42 dBm, and NS_ 15  may provide a spurious emissions limit of −53 dBm. To facilitate compliance with an instructed specification level, the radio frequency system may associate each specification level with a particular output power and a set of operational parameters implemented to achieve the output power. For example, the radio frequency system may implement a first set of operational parameters enabling transmission at a maximum output power when a network signaling value of NS_ 01  is received, a second set of operational parameters enabling transmission at a first reduced output power when a network signaling value of NS_ 12  is received, a third set of operational parameters enabling transmission at a second reduced power when a network signaling value of NS_ 13  is received, and a fourth set of operational parameters enabling transmission at a third reduced power when a network signaling value of NS_ 15  is received. 
     In other words, the radio frequency system may comply with a specification level instruction from a supervisory entity by adjusting output power of transmitted analog electrical signals between a maximum output power and one or more reduced output powers. In fact, some standardization bodies may specify a maximum amount of output power back off in relation to the maximum output power that may be used to be in compliance with each specification level. For example, the 3rd Generation Partnership Project (3GPP) may standardize that a maximum back off to comply with NS_ 12  is 6 dBm (e.g., Maximum Power Reduction+Additional Maximum Power Reduction) from the maximum output power. As such, it may be possible to design the radio frequency system to determine each reduced output power in relation to the maximum output power. 
     In some instances, the maximum output power may be adjusted (e.g., increased/decreased) based on various factors, such as various specifications (e.g., standards and/or regulations), power consumption, efficiency, and/or antenna performance. As such, when the reduced output powers are determined based on the maximum output power, each adjustment to the maximum output power may also affect performance of the radio frequency system at each of the reduced output powers. For example, when the maximum output power is increased, the reduced output powers may also be increased, thereby causing non-compliance with an instructed specification level. On the other hand, when the maximum output power is decreased, the reduced output powers may also be decreased, thereby reducing reliability of communication and producing a larger margin from the instructed specification level. 
     To account for such performance issues, the radio frequency system may be redesigned to adjust the reduced output powers and associated operational parameters each time the maximum output power is adjusted. As such, when the reduced output powers are determined based on the maximum output power, each adjustment to the maximum output power may lengthen and/or complicate the design process of the radio frequency system. 
     Accordingly, as will be described in more detail below, the present disclosure provides techniques to improve design and/or operation of a radio frequency system. In some embodiments, the radio frequency system may include a first look-up table (LUT) that specifies a back off value based on a received specification level (e.g., network signaling value) in relation to a static reference value. Additionally, the radio frequency system may include a second look-up table that specifies operational parameters associated with various output powers. Thus, the radio frequency system may control operation by determining a reduced output power based on the static reference value and the back off value determined from the first look-up table and by implementing operational parameters associated with the reduced output power determined from the second look-up table. 
     In this manner, the design process and/or operation of the radio frequency system may be improved. More specifically, although various factors may cause the maximum output power to be adjusted, the one or more reduced output powers may remain constant. As such, redesign costs associated with each adjustment to the maximum output power may be reduced because adjustments to the one or more reduced output power may be obviated. Additionally, in operation, transmission of analog electrical signals at one of the one or more reduced output powers may be in compliance with an instructed specification level, have improved transmission reliability (e.g., higher output power), and have reduced margin between operation (e.g., transmitted spurious emissions) and the specification level (e.g., allowable spurious emissions). 
     To help illustrate, an electronic device  10  that may utilize a radio frequency system  12  is described in  FIG. 1 . As will be described in more detail below, the electronic device  10  may be any suitable electronic device, such as a handheld computing device, a tablet computing device, a notebook computer, and the like. 
     Accordingly, as depicted, the electronic device  10  includes the radio frequency system  12 , input structures  14 , memory  16 , one or more processor(s)  18 , one or more storage devices  20 , a power source  22 , input/output ports  24 , and an electronic display  26 . The various components described in  FIG. 1  may include hardware elements (including circuitry), software elements (including computer code stored on a non-transitory 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 the electronic device  10 . Additionally, it should be noted that the various depicted components may be combined into fewer components or separated into additional components. For example, the memory  16  and a storage device  20  may be included in a single component. 
     As depicted, the processor  18  is operably coupled with memory  16  and the storage device  20 . More specifically, the processor  18  may execute instruction stored in memory  16  and/or the storage device  20  to perform operations in the electronic device  10 , such as instructing the radio frequency system  12  to communicate with another device. As such, the processor  18  may include one or more general purpose microprocessors, one or more application specific processors (ASICs), one or more field programmable logic arrays (FPGAs), or any combination thereof. Additionally, memory  16  and/or the storage device  20  may be a tangible, non-transitory, computer-readable medium that stores instructions executable by and data to be processed by the processor  18 . For example, the memory  16  may include random access memory (RAM) and the storage device  20  may include read only memory (ROM), rewritable flash memory, hard drives, optical discs, and the like. 
     Additionally, as depicted, the processor  18  is operably coupled to the power source  22 , which provides power to the various components in the electronic device  10 . For example, the power source  22  may supply direct current (DC) electrical power to the radio frequency system  12 . As such, the power source  22  may include any suitable source of energy, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. Furthermore, as depicted, the processor  18  is operably coupled with I/O ports  24 , which may enable the electronic device  10  to interface with various other electronic devices, and input structures  14 , which may enable a user to interact with the electronic device  10 . Accordingly, the inputs structures  14  may include buttons, keyboards, mice, trackpads, and the like. Additionally, in some embodiments, the electronic display  26  may include touch sensitive components. 
     In addition to enabling user inputs, the electronic display  26  may display image frames, such as a graphical user interface (GUI) for an operating system, an application interface, a still image, or video content. As depicted, the display is operably coupled to the processor  18 . Accordingly, the image frames displayed by the electronic display  26  may be based on display image data received from the processor  18 . 
     As depicted, the processor  18  is also operably coupled with the radio frequency system  12 , which may facilitate communicatively coupling the electronic device  10  to one or more other electronic devices and/or networks. For example, the radio frequency system  12  may enable the electronic device  10  to communicatively couple to a personal area network (PAN), such as a Bluetooth network, a local area network (LAN), such as an 802.11x Wi-Fi network, and/or a wide area network (WAN), such as a 4 G or LTE cellular network. As can be appreciated, the radio frequency system  12  may enable communication using various communication protocols and/or varying output powers (e.g., strength of transmitted analog electrical signals). 
     Operational principles of the radio frequency system  12  may be similar for each of the communication protocols (e.g., Bluetooth, LTE, 802.11x Wi-Fi, etc.). More specifically, as will be described in more detail below, the radio frequency system  12  may convert a digital electrical signal containing data desired to be transmitted into an analog electrical signal using a transceiver. The radio frequency system  12  may then amplify the analog electrical signal to a desired output using an amplifier component and output the amplified analog signal using one or more antennae. In other words, although described in a long-term evolution (LTE) context, the techniques described herein may be applicable to any suitable radio frequency system  12  that operates in any suitable manner regardless of communication protocol used. 
     As described above, the electronic device  10  may be any suitable electronic device. To help illustrate, one example of a handheld device  10 A is described in  FIG. 2 , which may be a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. For example, the handheld device  10 A may be a smart phone, such as any iPhone® model available from Apple Inc. As depicted, the handheld device  10 A includes an enclosure  28 , which may protect interior components from physical damage and to shield them from electromagnetic interference. The enclosure  28  may surround the electronic display  26 , which, in the depicted embodiment, displays a graphical user interface (GUI)  30  having an array of icons  32 . By way of example, when an icon  32  is selected either by an input structure  14  or a touch sensing component of the electronic display  26 , an application program may launch. 
     Additionally, as depicted, input structures  14  may open through the enclosure (e.g., housing)  28 . As described above, the input structures  14  may enable a user to interact with the handheld device  10 A. For example, the input structures  14  may activate or deactivate the handheld device  10 A, navigate a user interface to a home screen, navigate a user interface to a user-configurable application screen, activate a voice-recognition feature, provide volume control, and toggle between vibrate and ring modes. Furthermore, as depicted, the I/O ports  24  open through the enclosure  28 . In some embodiments, the I/O ports  24  may include, for example, an audio jack to connect to external devices. Additionally, the radio frequency system  12  may also be enclosed within the enclosure  28  and internal to the handheld device  10 A. 
     To further illustrate a suitable electronic device  10 , a tablet device  10 B is described in  FIG. 3 , such as any iPad® model available from Apple Inc. Additionally, in other embodiments, the electronic device  10  may take the form of a computer  10 C as described in  FIG. 4 , such as any Macbook® or iMac® model available from Apple Inc. As depicted, the tablet device  10 B and the computer  10 C also include an electronic display  26 , input structures  14 , I/O ports  24 , and an enclosure (e.g., housing)  28 . Similar to the handheld device  10 A, the radio frequency system  12  may also be enclosed within the enclosure  28  and internal to the tablet device  10 B and/or the computer  10 C. 
     As described above, the radio frequency system  12  may facilitate communication with other electronic devices and/or a network by wirelessly communicating data. To help illustrate, a portion  34  of radio frequency system  12  is described in  FIG. 5 . As depicted, the portion  34  includes a digital signal generator  36 , a transceiver  38 , an amplifier component  40 , one or more filters  42 , an antenna  44 , and a controller  46 . More specifically, the controller  46  may include one or more processors  48  and memory  50  to facilitate controlling operation of the radio frequency system  12 . For example, the controller  46  may instruct the amplifier component  40  and/or the one or more filters  42  to implement determined operational parameters, such as position/aggressiveness of filter rejection or amount of amplification. Accordingly, in some embodiments, the controller processor  48  may be included in the processor  18  and/or separate processing circuitry and the memory  50  may be included in memory  16  and/or a separate tangible non-transitory computer-readable medium. In some embodiments, the controller  46  may be included in the transceiver  38  or separately. 
     Additionally, the digital signal generator  36  may generate a digital representation of data desired to be transmitted from the electronic device  10  by outputting a digital electrical signal. Accordingly, in some embodiments, the digital signal generator  36  may include the processor  18  and/or a separate processing circuitry, such as a baseband processor or a modem in the radio frequency system  12 . 
     The transceiver  38  may then receive the digital electrical signal and generate an analog representation of the data. In some embodiments, the transceiver  38  may generate an analog representation by outputting an envelope voltage to indicate a desired output power of the radio frequency system  12  and an analog electrical signal to indicate phase (e.g., whether high or low) of the digital electrical signal. For example, when the desired output is 16.7 dBm, the transceiver  38  may output an envelope voltage of 1.2 volts. Additionally, when the digital electrical signal is high (e.g., “1”), the transceiver  38  may output an analog electrical signal with a positive voltage and, when the digital electrical signal is low (e.g., “0”), the transceiver  38  may output an analog electrical signal at zero volts. 
     Since the output power of the analog electrical signal may be small, the amplifier component  40  may receive and amplify the analog electrical signal by outputting an amplified analog electrical signal. More specifically the amplifier component  40  may vary amplitude of the amplified analog electrical signal to enable the output power of the radio frequency system  12  to be adjusted. For example, the amplifier component  40  may adjust amplitude of the amplified analog electrical signal based at least in part on the envelope voltage signal received from the transceiver  38 . 
     As can be appreciated, noise may be introduced by the transceiver  38  and/or the amplifier component  40 , such as spurious emissions or out of band emissions. As such, one or more filters  42  may remove introduced noise from the amplified analog electrical signal and output a filtered analog electrical signal. The filtered analog electrical signal may then be wirelessly transmitted to another electronic devices and/or a network via the antenna  44  as modulated radio waves. 
     In addition to transmitting analog electrical signals, the antenna  44  may receive analog electrical signals from another electronic device and/or a network. For example, the antenna  44  may receive an instruction from a supervisory entity, such as a wireless carrier, instructing the radio frequency system  12  to operate in compliance with a particular specification level. In some embodiments, received analog electrical signals may be received by the antenna  44 , filtered by the one or more filter  42 , and converted to a digital electrical signal by the transceiver  38 . The controller  46  may then determine the instructed specification level based on the digital electrical signal and instruct components in the radio frequency system  12  to adjust operation to be in compliance. For example, the controller  46  may instruct the amplifier component  40  to adjust amplification and the one or more filters  42  to adjust position and/or aggressiveness of filtering, thereby adjusting output power, out of band emissions, and/or spurious emissions transmitted from the radio frequency system  12 . 
     To help illustrate, a block diagram of the controller  46  is described in  FIG. 6 . As depicted, the controller  46  includes a network signaling value look-up table (NS_XX LUT)  52  and an operational parameter look-up table (LUT)  54 . In some embodiments, the network signaling value look-up table  52  and the operational parameter look-up table  54  may be stored in memory  50  and/or another suitable tangible, non-transitory, computer-readable medium. As will be described in more detail below, the controller  46  may utilize the network signaling value look-up table  52  and the operational parameter look-up table to determine operational parameters  55  to implement based at least in part on a network signaling value (NS_XX)  57  received from a supervisory entity. In other embodiments, the controller  46  may perform calculations instead of explicit look-up tables. Additionally, in other embodiments, the network signaling value look-up table  52  and/or the operational parameter look-up table  54  may include multiple look-up tables, for example, divided between pertinent sets of specifications, jurisdiction, frequency bands, and the like. 
     In the depicted embodiment, the network signaling value look-up table  52  includes a first row  56  that defines a static reference value, which in the depicted embodiment is 23 dBm. Additionally, the network signaling value look-up table  52  includes a second row  58  that defines a maximum output power associated with the network signaling value of NS_ 01 , which in the depicted embodiment is 24 dBm. Thus, in the depicted embodiment, the static reference value is lower than the maximum output power. In other embodiments, the static reference value and the maximum output power may be the same or the static reference value may be higher than the maximum output power. 
     Additionally, the network signaling value look-up table  52  may include multiple rows that each defines a back off value in relation to the static reference value, which may be used to determine reduced output powers associated with other network signaling values. For example, in the depicted embodiment, the network signaling value look-up table  52  includes a third row  60  that defines a back off value of 5 dBm associated with the network signaling value of NS_ 12 , a fourth row  62  that defines a back off value of 3 dBm associated with the network signaling value of NS_ 13 , and a fifth row  64  that defines a back off value of 2 dBm associated with the network signaling value of NS_ 15 . 
     Furthermore, the operational parameter look-up table  54  includes rows that define operational parameters associated with various output powers. For example, in the depicted embodiment, the operational parameter look-up table  54  includes a first row  66  that associates operational parameters with an output power of 18 dBm, a second row  68  that associates operational parameters with an output power of 20 dBm, a third row  70  that associates operational parameters with an output power of 21 dBm, a fourth row  72  that associates operational parameters with an output power of 23 dBm, and a fifth row  74  that associates operational parameters with an output power of 24 dBm. In some embodiments, the operational parameters  55  may be implemented to adjust output power, out of band emissions, and/or spurious emissions transmitted from the radio frequency system  12 . For example, the operational parameters  55  may include position (e.g., frequency) of filter rejection, aggressiveness of filter rejection, amplification of the amplifier component  40 , or any combination thereof. 
     As such, the radio frequency system  12  may transmit analog electrical signals in compliance with a received network signaling value  57  by implementing determined operational parameters  55 . To help illustrate, a process  76  for transmitting analog electrical signals is described in  FIG. 7 . Generally, the process  76  includes powering on a radio frequency system (process block  78 ), determining a network signaling value look-up table (process block  80 ), determining an operational parameters look-up table (process block  82 ), determining a network signaling value (process block  84 ), determining a desired output power (process block  86 ), determining associated operational parameters (process block  88 ), and wirelessly transmitting analog electrical signals (process block  90 ). In some embodiments, the process  76  may be implemented using instructions stored in the memory  50  and/or another suitable tangible non-transitory computer-readable medium and executable by the processor  48  and/or another suitable processing circuitry. 
     The radio frequency system  12  may be powered on when electrical power is supplied to the radio frequency system  12 , for example, from the power source  22  (process block  78 ). In some embodiments, electrical power may be supplied when the electronic device  10  is powered on. Additionally or alternatively, electrical power may be supplied when the electronic device  10  desires to wirelessly communicate with another electronic device and/or a network. 
     Upon powering on, the radio frequency system  12  may determine the network signaling value look-up table (NS_XX LUT)  52  (process block  80 ) and the operational parameters look-up table (LUT)  54  (process block  82 ). In some embodiments, the network signaling value look-up table  52  and the operational parameters look-up table  54  may be predetermined by a manufacturer and stored in the memory  16 ,  50 , or another tangible, non-transitory, computer-readable medium. As such, the radio frequency system  12  may determine the network signaling value look-up table  52  and the operational parameters look-up table  54  by polling the memory  16  or  20 . Additionally, when multiple network signaling value look-up tables  52  and/or operational parameter look-up tables  54  are stored, the radio frequency system  12  may determine the relevant look-up tables based at least in part on pertinent sets of specifications, jurisdiction, frequency band, and the like. 
     Additionally, once connected to another electronic device and/or a network, the radio frequency system  12  may receive instructions from a supervisory entity to communicate in compliance with a particular specification level (e.g., network signaling value) (process block  84 ). In some embodiments, the radio frequency system  12  may receive the specification level via the antenna  44  as an analog electrical signal and the transceiver  38  may convert the analog electrical signal into a digital electrical signal. 
     Based on the instructed specification level, the radio frequency system  12  may determine a desired output power to be in compliance using the network signaling value look-up table  52  (process block  86 ). As described above, the network signaling value look-up table  52  may describe a static reference value, a maximum output power associated with a first specification level (e.g., NS_ 01 ), and one or more back off values in reference to the static reference value associated with one or more other specification levels (e.g., NS_ 12 , NS_ 13 , and NS_ 15 ). Thus, using the network signaling value look-up table  52 , the radio frequency system  12  may determine that the desired output power is either the maximum output power or a reduced output power determined based on the static reference value and a back off value (e.g., static reference value—back off value). 
     For example, when a network signaling value of NS_ 01  is received, the radio frequency system  12  may determine that the desired output power is 24 dBm (e.g., a maximum output power). Additionally, when a network signaling value of NS_ 12  is received, the radio frequency system  12  may determine that the static reference value is 23 dBm and the back off value is 5 dBm. As such, the radio frequency system  12  may determine that a first reduced output power is 18 dBm (e.g., a first reduced output power). In a similar manner, the radio frequency system  12  may determine that a second reduced output power is 20 dBm (e.g., a second reduced output power) when a network signaling value of NS_ 13  is received and that a third reduced output power is 21 dB (e.g., a third reduced output power) when a network signaling value of NS_ 15  is received. 
     In some instances, the radio frequency system  12  may adjust the maximum output power associated with the network signaling value of NS_ 01  during operation based on other specifications (e.g., standards or regulations). For example, based on proximity to a user&#39;s body, the maximum output power may be reduced to be in compliance with regulations set by the FCC. In other words, in some instances, the maximum output power may end up being less than the static reference value minus a back off value determined from the network signaling value look-up table  52 . As such, to facilitate compliance with any such specifications, the radio frequency system  12  may determine that the desired output power is the lesser of the maximum output power and a determined reduced output power (e.g., static reference value minus back off value). For example, continuing with the above example, if the maximum output power is reduced to 14 dBm, the radio frequency system  12  may determine that the desired output power is 14 dBm when a network signaling value of NS_ 15  is received even though the determined reduced output power is 21 dBm. 
     Based on the desired output power, the radio frequency system  12  may determine operational parameters to implement using the operational parameters look-up table  54  (process block  88 ). As described above, the operational parameters look-up table  54  may describe operational parameters associated with multiple output powers. For example, the radio frequency system may identify operational parameters in the first row  66  when the desired output is 18 dBm, the second row  68  when the desired output is 20 dBm, the third row  70  when the desired output is 21 dBm, the fourth row  72  when the desired output is 23 dBm, and the fifth row  74  when the desired output is 24 dBm. In some embodiments, the operational parameters may include position (e.g., frequency) of filter rejection by the one or more filters  42 , filtering aggressiveness by the one or more filter  42 , amplification by the amplifier component  40 , or any combination thereof. 
     The radio frequency system  12  may then wirelessly transmit analog electrical signals using the identified operational parameters  55  (process block  90 ) until a different network signaling value is received (arrow  92 ). As described above, the radio frequency system  12  may operate in compliance with the instructed specification level because the reduced output powers are determined independent from the maximum power output. To help illustrate, in the example described in  FIG. 6 , when a network signaling value of NS_ 13  is received, the radio frequency system  12  may determine that the desired output power is 20 dBm by applying the back off value of 3 dBm to the static reference value of 23 dBm. As such, the radio frequency system  12  may implement operational parameters in the second row  68  of the operational parameters look-up table  54 . 
     However, if the reduced output power is determined based on the maximum output power of 24 dBm, the radio frequency system  12  may determine that the reduced output power is 21 dBm when a network signaling value of NS_ 13  is received and implement operational parameters in the third row  70  of the operation parameters look-up table  54 . In fact, since the determined output power is higher, this may result in the radio frequency system  12  not being in compliance with the instructed specification level (e.g., NS_ 13 ). To further illustrate, if the reduced output power is determined based on a maximum output power of 22 dBm, the radio frequency system  12  may determine that the reduced output power is 19 dBm when a network signaling value of NS_ 13  is received and implement associated operational parameters. Since the determined output power is lower, this may result in reduced transmission reliability and additional margin from the specification level (e.g., NS_ 13 ). 
     Thus, by defining the reduced output powers in relation to a static reference value, the radio frequency system may operate in compliance with an instructed specification level and improving transmission reliability with reduced margin between operation (e.g., spurious emissions) and the instructed specification level (e.g., spurious emissions standards). As described above, in addition to improving operational performance, defining the reduced output powers in relation to a static reference value may also improve the design process of the radio frequency system  12 . 
     To help illustrate, one embodiment of a process  94  for designing a radio frequency system  12  is described in  FIG. 8 . Generally, the process  94  includes determining standards associated with network signaling values (process block  96 ), determining a maximum output power (process block  98 ), determining a static reference value (process block  100 ), determining a network signaling value look-up table (process block  102 ), determining an operational parameters look-up table (process block  104 ), and optionally adjusting the maximum output power (process block  104 ). In some embodiments, the process  94  may be implemented by a manufacturer of the radio frequency system  12  using instructions stored in a suitable tangible non-transitory computer-readable medium and executable by a suitable processing circuitry. 
     Accordingly, the manufacturer may determine the standards associated with various network signaling values (NS_XX) (process block  96 ). In some embodiments, the network signaling value standards may be received from a standardization body. For example, the manufacturer may receive standards on allowable out of band emissions, allowable spurious emissions, and maximum back off in relation to the maximum output power for multiple network signaling values from the 3rd Generation Partnership Project (3GPP). 
     The manufacturer may then determine a maximum output power based at least in part on the network signaling value standards (process block  98 ). Generally, the maximum output power may be determined based on various factors, such as various specification (e.g., standards or regulations), power consumption, efficiency, and/or antenna performance. For example, the 3rd Generation Partnership Project (3GPP) sets a standard that the maximum output power be between 21-25 dBm. Additionally, within the standardized range, the maximum output power may be determined to, for example, meet spurious emissions limits in protected/restricted frequency bands and/or balance power consumption (e.g., battery life) with antenna performance (e.g., transmission reliability). 
     Additionally, the manufacturer may determine a static reference value (process block  100 ). As discussed above, the 3rd Generation Partnership Project (3GPP) provides a maximum back off value for each network signaling value in relation to the maximum output power. As such, the manufacturer may define the static reference value close to or the same as the maximum output value to facilitate compliance with the maximum back off standards. For example, in some embodiments, the static reference value may be determined as a common or initial maximum output power, such as 23 dBm. 
     The manufacturer may then determine the network signaling value look-up table (NS_XX LUT)  52  (process block  100 ). As described above, the network signaling value look-up table  52  may associate multiple network signaling values with either a maximum output power or a back off value in relation to the static reference value. More specifically, based on the network signaling value standards, the manufacturer may determine desired output powers to be in compliance with an instructed network signaling value. For example, the manufacturer may determine that operating at the maximum output power enables compliance with a first network signaling value (e.g., NS_ 01 ) and store the association in the network signaling value look-up table  52 . In some embodiments, the manufacturer may in fact determine multiple network signaling value look-up tables  52  based on pertinent sets of specifications, jurisdiction, frequency bands, and the like. 
     Additionally, the manufacturer may determine that a reduced output power enables compliance with a second network signaling value. More specifically, when the desired output power is a reduced output power, the manufacturer may determine a back off value in relation to the static reference value that results in the reduced output power. For example, when the static reference value is 23 dBm and the desired output power is 20 dBm, the manufacturer may determine that the back off value is 3 dBm even though the maximum output power may be 24 dBm. As such, the manufacturer may determine a back off value used to determine a reduced output power that enables compliance with a second network signaling value and store the associated back off value in the network signaling value look-up table  52 . In some embodiments, the manufacturer may in fact determine multiple operational parameter look-up tables  54  based on pertinent sets of specifications, jurisdiction, frequency bands, and the like. 
     The manufacturer may then determine the operational parameters look-up table (LUT) (process block  104 ). More specifically, the manufacturer may determine operational parameters of the radio frequency system  12 , which when implemented enable the radio frequency system  12  to transmit analog electrical signals at the desired output power and in compliance with the instruct network signaling value. For example, the operational parameters may include position (e.g., frequency) of filter rejection by one or more filters  42 , aggressiveness of filter rejection by the one or more filters  42 , amplification by the amplifier component  40 , or any combination thereof. In some embodiments, the operational parameters may be determined by running the radio frequency system  12  through testing to determine out of band emissions and spurious emissions with various sets of operational parameters. The manufacturer may enter the determined operational parameters in the operational parameters look-up table  54  and store the operational parameters look-up table  54  in memory  50 . 
     As described above, the maximum output power may be determined based on factors such as various specifications (e.g., regulations or standards), power consumption, efficiency, and/or antenna performance. As such, during the design process, the maximum output power may be adjusted (process block  104 ). However, since the back off values associated with the network signaling values in the network signaling value look up table  52  and the operational parameters associated with the reduced output powers in the operational parameters look-up table  54  are determined relatively independent from the maximum output power, they may remain largely unchanged. In this manner, the redesign associated with adjusting the maximum output power may be reduced, thereby improving the design process. 
     Accordingly, the technical effects of the present disclosure include improving design and/or operation of a radio frequency system, particularly at reduced output powers. More specifically, the radio frequency system may be designed so that reduced output powers and associated operational parameters are determined relatively independently from a maximum output power. As such, redesign of the radio frequency system when the maximum output power is adjusted may be reduced. Additionally, the operational parameters associated with an instructed specification level may be determined independently from the maximum output power. As such, even at varying maximum output powers, the operational parameters may be implemented such that the radio frequency system operates in compliance with the instructed specification level and with improved transmission reliability (e.g., reduced margin from the instructed specification level). 
     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. 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.

Metadata:
Filing Date: 20150306
Publication Date: 20170131
Grant Date: 20170131
Priority Date: 20150306
Inventors: LI JIANJIAN
Jain Vikas O.
AGBOH PETER M.
Mangtani Kaushal K.
WALIA MANJIT S.
NARANG MOHIT
MEHTA ABHISHEK
CABALLERO RUBEN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04W52/226", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W52/367", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W52/52", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/226", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04W52/52", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/367", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 56851248