Patent Publication Number: US-2018041288-A1

Title: Methods using a hand phantom for evaluating tablets in a wireless communication system

Description:
TECHNICAL FIELD 
     The present disclosure is related generally to measuring radiated power of wireless devices and, more particularly, to measuring the radiated power of a wireless tablet device that is proximate to a phantom. 
     BACKGROUND 
     The 3rd Generation Partnership Project (3GPP) is the organization for the standardization of the Universal Mobile Telecommunication System (UMTS) and Long Term Evolution (LTE). Wireless communication is continuously evolving. There are many types of advanced technology equipment being introduced that can provide services that were not possible previously. This advanced technology equipment might include, for example, an Enhanced Node B (eNB) or other systems and devices that are more highly evolved than the equivalent equipment in a traditional wireless telecommunications system. Such advanced or next generation equipment may be referred to herein as High Speed Packet Access (HSPA) equipment, LTE, whose networks are also known as Evolved Universal Terrestrial Access Network (E-UTRAN), is a technology that can reach high data rates both in the downlink as well as in the uplink. LTE allows for a system bandwidth of 20 MHz, or up to 100 Hz with certain features. Devices with wireless communications capabilities, such as tablets, will be referred to herein as User Equipment (UE) or wireless devices. 
     A tablet is a portable personal computer that combines the computer and the display into a single form factor. In various tablets, user input is accomplished through a touchscreen. Any reference herein to wireless devices or user equipment also applies to tablets. Alternatively, any wireless device herein may be a tablet and any user equipment described herein may be a tablet. 
     A heterogeneous network (HetNet) is a network that includes infrastructure points with various wireless access technologies, each of them having different capabilities, constraints, and operating functionalities. A typical HetNet includes a mix of macrocells, remote radio heads, and low-power nodes such as picocells, femtocells, and relays. 
     Leveraging network topology, increasing the proximity between the access network and the end-users, has the potential to provide the next significant performance leap in wireless networks, improving spatial spectrum reuse and enhancing indoor coverage. 
     Different UEs might use different types of radio access technology (RAT) to access a wireless communications network. Some UEs, referred to as multi-mode UEs, are capable of communicating using more than one RAT. For example, multi-mode UEs may include UEs that can obtain service from at least one mode of UMTS, and one or more different technologies such as GSM (Global System for Mobile Communications) or other radio systems. As defined herein, multi-mode UEs may be of any various type of multi-mode UE as defined or provided in 3GPP, Technical Specification Group (TSG) Terminals, Multi-Mode UE Issues, Categories, Principles and Procedures (3G TR 21.910). Some examples of RATs or network technologies that might use different types of RATs include UTMS Terrestrial Radio Access Network (UTRAN), GSM, GSM Enhanced Data rates for Global Evolution (EDGE) Radio Access Network (GERAN), Wireless Fidelity (WiFi), General Packet Radio Service (GPRS), High-Speed Downlink Packet Access (HSDPA), HSPA, and LTE. Other RATs or other network technologies based on these RATs may be familiar to one of skill in the art. 
     Government agencies frequently regulate how much power wireless devices are permitted to radiate. This is because the radiated power of a wireless device can potentially interfere with other devices. Therefore, wireless device manufacturers typically measure radiated power as part of the normal test process for such devices. 
     There are at least two different ways to measure the radiated power of a wireless device. One way is to measure the Equivalent Isotropically Radiated Power (EIRP) in an arbitrary direction. Another is to measure the total radiated power (TRP) emitted to the entire space. Measuring EIRP is considered to be complicated and time consuming. Consequently, TRP is usually measured instead of EIRP. 
     The Specific Absorption Rate (SAR) is also something that wireless device manufacturers and carriers may need to take into consideration. The SAR is used to measure impact on the human body from the exposure of the radio-frequency electromagnetic field generated by the wireless device. SAR is a measure of the maximum energy absorbed by a unit of mass of exposed tissue of a person using a wireless device over a given time. In other words, it is the power absorbed per unit mass. There are many wireless devices types that can be used in many positions relative to the human body, e.g. speech and data communications with different SAR performance requirements. 
     The over-the-air (OTA) performance of a wireless device is normally dependent on the antenna performance. The human body may affect the antenna performance since wireless devices, such as tablets, are often used in close proximity to a human body. To simulate a human body for the purpose of evaluating antenna performance of a wireless device, an anthropomorphic human body (or parts thereof) is often used. The term “phantom” as used herein refers to one or more parts of an anthropomorphic human body. While telephone-based wireless devices are typically tested next to or attached to a human head model, which is called Specific Anthropomorphic Mannequin (SAM) head phantom, for a tablet, the SAM is designed to take into consideration the influences of blocking and reflection and/or absorption of radio waves by a human hand. The SAM phantom has been standardized by the International Electrotechnical Commission (IEC). 
     When a person holds a tablet or wireless device in his or her hand or on a surface near his or her hand (e.g., for web browsing), this position is often referred to as a “data communication mode.” In the data communication mode, the antenna performance of the tablet or wireless device may be affected by the human hand. The data communication mode can be simulated by a hand phantom. The shapes and grip of the hand phantom should be based on premise of a communication state. Accordingly, the hand phantom should have a posture specific to the data communication mode. 
     SUMMARY 
     According to various embodiments, on a user equipment that is proximate to a phantom, a method for determining the total radiated power of the user equipment includes in response to a preset criterion, obtaining a characteristic of the phantom, obtaining a characteristic of an antenna of the user equipment, and obtaining a radio characteristic of the user equipment. The method may also include transmitting the phantom characteristic, the antenna characteristic, and the radio characteristic to a test equipment. The user equipment may be a tablet. 
     In some embodiments, the method further includes detecting a trigger measuring condition and carrying out the obtaining steps and the transmitting step in response to detecting the trigger measuring condition. 
     The trigger measuring condition may be the user equipment moving away from a serving cell and toward the test equipment. 
     The criterion may be a single event or a periodical event. 
     In some embodiments, the method further includes repeating the obtaining of the phantom characteristic, the obtaining of the antenna characteristic, and the obtaining of the radio characteristic for different configurations of the user equipment relative to the phantom. 
     The different configurations may be different positions of the user equipment relative to the phantom. 
     In some embodiments, the phantom is a hand phantom, and the different configurations comprises are different positions of the user equipment within the grip of the phantom. 
     In some embodiments, the different configurations include a data communication mode. 
     In some embodiments, the phantom is a hand phantom and the characteristic is the deflection of a finger on the hand phantom. 
     Another aspect is a method for determining the total radiated power of a user equipment is carried out on a test device. The user equipment may be a tablet. The method includes requesting a report from the user equipment. In response to the request, from the user equipment is received a report comprising a characteristic of a phantom that is proximate to the user equipment, a characteristic of an antenna of the user equipment, and a radio characteristic of the user equipment. The impact of the phantom characteristic, the antenna characteristic, and the radio characteristic on the radiated power of the user equipment is determined. The total radiated power in light of the phantom characteristics, antenna characteristics, and radio characteristics is calculated. An updated phantom characteristic, an updated radio characteristic, and an updated antenna characteristic is detected or obtained. 
     In some embodiments, the method for determining the total radiated power of a user equipment also includes repeating the determining, calculating and the detecting or obtaining steps until a test is complete. 
     In some embodiments of this method, the phantom is a hand phantom and the characteristic is the deflection of a finger on the hand phantom. 
     In yet another aspect is provided a user equipment which includes an antenna, a memory, and a processor. The user equipment may be a tablet. In this embodiment, the processor retrieves instructions from the memory and executes the instructions to obtain (in response to a preset criterion) a characteristic of the phantom, obtain a characteristic of an antenna of the user equipment, and obtain a radio characteristic of the user equipment. The phantom characteristic, the antenna characteristic, and the radio characteristic are transmitted to a test equipment. 
     In some embodiments the processor also detects a trigger measuring condition carries out the obtaining steps and the transmitting step in response to detecting the trigger measuring condition. 
     In some embodiments, the trigger measuring condition is the user equipment moving away from a serving cell and toward the test equipment. 
     In some embodiments, the processor repeats the obtaining of the phantom characteristic, the obtaining of the antenna characteristic, and the obtaining of the radio characteristic for different configurations of the user equipment relative to the phantom. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the appended claims set forth the features of the present techniques with particularity, these techniques, together with their objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a block diagram of a system according to an embodiment of the disclosure. 
         FIG. 2  is a block diagram of a UE or a test equipment according to an embodiment. 
         FIG. 3  is a diagram of a head phantom as an illustration of how a coordinate system can be established. 
         FIG. 4  is a diagram of a hand phantom according to an embodiment. 
         FIG. 5  is a flowchart of a method for measuring signal strength according to an embodiment. 
         FIG. 6  is a flowchart of a method for obtaining phantom, radio and antenna characteristics information according to an embodiment; 
         FIG. 7  is a flowchart of a method for obtaining phantom, radio and antenna characteristics information according to another embodiment; 
         FIG. 8  is a diagram that illustrates an example of a trigger measuring condition according to an embodiment; 
         FIG. 9  is a diagram of a data transmission according to an embodiment; 
         FIG. 10  is a flowchart of a method for obtaining a phantom characteristic, a radio characteristic, and an antenna characteristic according to an embodiment; and 
         FIG. 11  depicts an embodiment of a method for passive and active measurement of an over-the-air test system according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According to various embodiments, a method for measuring the total radiated power of tablets or wireless devices using the phantom characteristics, radio characteristics, and antenna characteristics in conjunction with a hand phantom is proposed. 
     A system is provided for measuring the total radiated power of tablets, wireless devices and user equipment (UE) using the phantom characteristics, radio characteristics, and antenna characteristics in conjunction with a hand phantom. The system may include one or more of test equipment, a UCE and a phantom. The UE may be a multi-mode UE that is capable of communicating via multiple RATs. The multimode UE can include a processor configured to promote measurements of a signal strength in a communication system. The UE may be a tablet. 
     An exemplary embodiment of this system is shown in  FIG. 1 . In this embodiment, a system  100  that may be used to carry out various embodiments is generally labeled  100 . The system  100  is located within a closed, spheroid chamber  101 . The system  100  includes test equipment  102 , a UE  104 , and a phantom  112 . In an embodiment, the UE  104  is a multi-mode UE that is capable of communicating via multiple RATs. Coupled to the test equipment  102  are one or more antennas (e.g., one for each RAT used by the test equipment  102 ), represented by antennas  105  and  106 . The user equipment  104  includes one or more antenna (e.g., one for each RAT used by the user equipment  104 ), represented by antennas  108  and  110 . The user equipment  104  is located proximate to the phantom  112 . One or both of the test equipment  102  and the user equipment  104  may be in communication with a serving cell  114  and be within communication range of a neighboring cell  116 . 
     According to another embodiment, radio waves emitted from a tablet or wireless device to be measured are reflected from an anechoic chamber or reverberation chamber and are then concentrated on the receiving antenna, with the total radiated power of the wireless device being measured. This embodiment is also illustrated in  FIG. 1 , where the chamber  101  is an anechoic chamber or a reverberation chamber. During a testing procedure, the UE  104  and the test equipment  102  are each placed at respective focal position of the chamber  101 , with the UE  104  being placed proximate to the phantom  112 . The UE  104  emits radio waves, which reflect off of inner walls of the chamber  101 . Those reflected waves are concentrated on one or more of the antennas of the test equipment  102 . The test equipment  102  then measures the TRP of the UE  104  in accordance with various methods described herein, taking into account one or more characteristics of the phantom  112 , one or more characteristics of an antenna of the UE  104 , and one or more radio characteristics of the UE  104 . Having information regarding the phantom characteristics, radio characteristics, and antenna characteristics available allows the test equipment  102  to make more accurate calculations, which in turn may lead to improvement in measuring radiation power. By carrying out a test according to an embodiment, performance of the UE  104  can thereby be improved. 
     In various embodiments, one or more of the test equipment  102  and the user equipment  104  includes one or more of the components of  FIG. 2 . Turning to  FIG. 2 , the components include a first RAT transceiver  202 , which is capable of sending and receiving data via a first RAT, and a second RAT transceiver  204 , which is capable of sending and receiving data via a second RAT. The first RAT transceiver  202  and the second RAT transceiver  204  are each linked to respective antennas  105  and  106 , or  108  and  110 . The components of  FIG. 2  further include a (hardware) processor  206 , a memory  208 , and user interface devices  210  (e.g., one or more of a touchscreen display and physical buttons), and a network interface  212 . Each of these elements is communicatively linked to one another via one or more data pathways  214 . Examples of data pathways include wires, conductive pathways on a microchip, and wireless connections. In one embodiment, all of the components of  FIG. 2  are enclosed within a housing  216 . 
     During operation of the test equipment  102  or the user equipment  104 , one or more of the transceivers  202  and  204  receives data from the processor  206  and transmits radio-frequency signals representing the data via one or more of the antennas  105 ,  106 ,  108 , and  110 . Similarly, one or more of the transceivers  202  and  204  receives radio-frequency signals via one or more of the antennas  105 ,  106 ,  108 , and  110 , converts the signals into the appropriately formatted data, and provides the data to the processor  206 . The processor  206  retrieves instructions from the memory  208  and, based on those instructions, provides outgoing data to one or more of the transceivers  202  and  204  or receives incoming data from the one or more of the transceivers  202  and  204 . Similarly, based on the instructions, the processor  206  carries out one or more of the various methods disclosed herein, such as making the various measurements discussed herein, transmitting the various reports discussed herein in order to promote the measurement of a signal strength in a communication system. 
     The processor  206  may be any programmable device such as a computer, a microprocessor, a microcontroller, a set of peripheral integrated circuit elements, an integrated circuit (e.g., an application-specific integrated circuit), hardware/electronic logic circuits (e.g., a discrete element circuit), a programmable logic device (e.g., a programmable logic array), or a field programmable gate-array. 
     Possible implementations of the memory  208  include volatile memory, non-volatile memory, electrical, magnetic optical memory, random access memory (RAM), cache, and hard disc. 
     Turning to  FIG. 3 , an illustration of a head phantom  112  is shown. The phantom in this embodiment is a head phantom  300 . The head phantom  300  includes a cheek part  302 , a left ear part  304 , a right ear part  306 , and a mouth part  308 . The head phantom  300  is located in an XY coordinate system which is known to both the test equipment  102  and the UE  104 . The orientation of the UE  104  with respect to the left ear part  304 , the right ear part  306 , and the mouth part  308  is defined as a +X direction along an X-axis  310  and +Y direction along a Y-axis  312 . The UE  104  can be coupled to the hand phantom  300  in a data communication mode. 
     Turning to  FIG. 4 , another embodiment of the phantom  112  is shown. The phantom in this embodiment is a hand phantom  400 . The hand phantom  400  includes a thumb part  402 , an index finger part  404 , a middle finger part  406 , a ring finger part  408 , and a pinky finger part  410 , and in an XY coordinate system where for the tablet or wireless device being held, an orientation of the deflection of the index finger is defined as a +X direction along an X-axis  412  and +Y direction along a Y-axis  414  within the range of 2 and 5 mm. In an embodiment, an orientation of the hand grip is defined as a +X direction along the X-axis  412  and +Y direction along the Y-axis  414 . The coordinate system is known to both the test equipment  102  and the UE  104  in an embodiment. 
     Possible characteristics of the hand phantom  400  (including finger characteristics) include those set forth in Table 1 and Table 2. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Hand Phantom Characteristics 
               
            
           
           
               
               
               
            
               
                 ID 
                 Hand Grip Placement 
                 Characteristic Type 
               
               
                   
               
               
                 0 
                 Low 
                 Shift Up 
               
               
                 1 
                 Medium 
                 No Shift 
               
               
                 2 
                 High 
                 Shift Down 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Hand Phantom Index Finger Characteristics 
               
            
           
           
               
               
               
            
               
                 ID 
                 Deflection of Index Finger (df) Placement 
                 Characteristic Type 
               
               
                   
               
               
                 0 
                 df ≧ 2 mm per 20 g 
                 Rigid 
               
               
                 1 
                 2 mm &lt; df ≦ 7 mm per 20 g 
                 Stable 
               
               
                 2 
                 df &gt; 7 mm per 20 g 
                 Soft 
               
               
                   
               
            
           
         
       
     
     Turning to  FIG. 5 , a method that is carried out—e.g., by the UE  104 —to measure signal strength in an embodiment will now be described. At block  500 , a pilot strength is measured. For example, a UE may measure the strength of a pilot signal from an advanced technology network (e.g., an LTE network). At block  502 , a reporting configuration for the UE is set. For example, the UE  104  is configured to report one or more characteristics of the phantom  112 , a characteristic (or characteristics) of one or more of the antennas of the UE  104 , and one or more radio characteristics being experienced by the UE  104 . A criterion that triggers the UE to send the report may be a periodical event or a single event. At block  504 , the UE is configured to receive an interference report. For example, the UE (such as the UE  104 ) is configured to receive a report to inform a serving cell (such as the serving cell  114 ) to inform the serving cell of the interference capability of the UE based on measurements received by the UE from the serving cell and a neighboring cell (such as the neighboring cell  116 ). 
     Turning to  FIG. 6 , a method that is carried out by the test equipment  102  to obtain phantom characteristics, radio characteristics, and antenna characteristics from the UE  104  according to an embodiment will now be described. At block  600 , the test equipment  104  requests phantom characteristics, radio characteristics, and antenna characteristics from the UE  104 . The UE  104  responds by determining one or more of the characteristics of the phantom  112 , obtaining the radio characteristics of the UE  104 , obtaining the antenna characteristics of one or more of the antennas of the UE  104 , and transmitting these three pieces of information to the test equipment  102  (e.g., in a report in an OTA transmission). At block  602 , the test equipment  102  receives the requested phantom characteristics, radio characteristics, and antenna characteristics (i.e., in the report). At block  604 , the test equipment  102  determines the impact of the phantom characteristics, radio characteristics, and antenna characteristics on the TRP of the UE  104  (e.g., determines how to adjust its calculations of the TRP to account for those characteristics). At block  606 , the test equipment  102  calculates the TRP of the UE  104  in light of the phantom characteristics, radio characteristics, and antenna characteristics. In some embodiments, at block  607 , the position of the UE  104  relative to the phantom is changed. At block  608 , the test equipment  608  detects or obtains updated phantom characteristics, radio characteristics, and antenna characteristics—e.g., from a subsequent report received from the UE  104  or from input by a user at the test equipment  102 . At block  610 , the test equipment  102  determines whether the test (e.g., the overall test of TRP for the UE  104 ) is complete. If yes, then the process ends. If no, then the process moves back to block  604 . 
     Turning to  FIG. 7 , a method that is carried out by the UE  104  to obtain phantom characteristics, radio characteristics, and antenna characteristics according to an embodiment will now be described. At block  700 , the UE  104  receives a request—e.g., from the test equipment  102 —for phantom characteristics, radio characteristics, and antenna characteristics. Otherwise, the UE  104  waits. At block  702 , if the UE  104  detects a trigger measuring condition, it moves to block  704 . At block  704 , the UE  104  obtains one or more characteristics of the phantom  112 , measures its own radio characteristics, and measures characteristics of one or more of the antennas of the UE  102 . At block  706 , the UE  104  transmits the phantom characteristics, the radio characteristics, and the antenna characteristics to the test equipment  102 . In some embodiments, the configuration of the UE  104  is changed after block  706 . For example, the configuration of the UE  104  is enter and exit a data communication mode. Or the position of the UE  104  may be changed relative to the phantom  112 . At block  708 , the UE  104  detects or obtains updated phantom characteristics, updated radio characteristics, and updated antenna characteristics. At block  710 , if the test is complete, then the process ends. If the test is not complete, then the process continues returns to block  706 . 
     Turning to  FIG. 8 , an example of a trigger measuring condition (i.e., one that may occur when a measurement criterion has been fulfilled) will now be described. In this example, the measurement criterion is that a UE  800  (which could be the UE  104  of  FIG. 1 ) is receiving data, in the form of a data transmission  801  from an eNB of a macro technology network  802  (which could be the serving cell  114 ) and is moving away from the macro technology network  802  but closer to a micro technology network  804  (which could be the test equipment  102 ). Thus, when the UE  800  determines that it is moving away from the macro technology network  802  but closer to the micro technology network  804 , the UE  800  responds by (i.e., is triggered to) carrying out the steps set forth in blocks  704  through  710  of  FIG. 7 . 
       FIG. 9  illustrates a detailed view of a data transmission that a UE may send according to an embodiment. The data transmission includes a series data strings separated by transmission period in which no data is transmitted. The data strings might represent some type of a user-directed data transmission. During the period in which no data is transmitted, the UE can measure the strengths of the signals that it receives. 
     Turning to  FIG. 10 , a method for determining the radiated power of a tablet or wireless device according to an embodiment will now be described. At block  1000 , the wireless device (e.g., the UE  104 ) and a receiving antenna (e.g., that of the test equipment  102 ) are placed (e.g., at focal positions of the chamber  101 ). At block  1002 , the measurement frequency is set with the wireless device in a directly connected state (e.g., with the UE  104  and the test equipment  102  being directly connected), and the positions (e.g., of the UE  104  and the test equipment  102 ) are adjusted. At block  1004 , the maximum value to the minimum value of the radiated power of the wireless device is calculated (e.g., by the test equipment  102 ). At block  1006 , the ratio of the maximum value to the minimum value (calculated at block  1004 ) is calculated (e.g., by the test equipment  102 ). At block  1008 , the transmitting antenna (e.g., one or more of the antennas of the UE  104  or the entire UE  104 ) and the receiving antenna (e.g., one or more of the antennas of the test equipment  102 ) are set (e.g., positioned at the focal points of the chamber  101 ). At block  1010 , the measurement frequency is set with the wireless device in a directly connected state (e.g., with the UE  104  and the test equipment  102  being directly connected), and the positions (e.g., of the UE  104  and the test equipment  102 ) are adjusted. At block  1012 , the maximum value to the minimum value of the radiated power of the wireless device is calculated (e.g., by the test equipment  102 ). At block  1014 , the ratio of the maximum value to the minimum value (calculated at block  1004 ) is calculated (e.g., by the test equipment  102 ). 
     Finally,  FIG. 11  depicts an embodiment of a method for passive and active measurement of an OTA test system. 
     According to various embodiments, the methods and devices described herein determine the radio resources and/or configuration parameters for testing a tablet or wireless device based on obtained phantom, radio, and antenna characteristics. Having the phantom, radio and antenna characteristics information available enables a system to make more accurate decisions, which in turn may lead to improvement in measuring radiation power. 
     In yet another aspect is provided a method to measure the total radiated power of tablets or wireless devices using the obtained phantom, radio and antenna characteristics and using a hand phantom, with the following steps carried out: 1) Perform a measurement; 2) Request phantom, radio and antenna characteristics; 3) Obtain phantom, radio and antenna characteristics; 4) Determine phantom, radio and antenna characteristics in relation to total radiated power; 5) Use phantom, radio and antenna characteristics in relation to total radiated power; 6) Detect/obtain updated phantom, radio and antenna characteristics; 7) Reporting configuration is set based on the criterion that triggers a multi-mode UE to send a measurement report; 8) The wireless device to be measured and a receiving antenna are arranged such as to focal positions of the closed space, which forms a spheroid; 9) Set wireless device to be measured and receiving antenna; 10) Set measurement frequency in directly connected state and adjust positions; 11) Calculate maximum value to minimum value; 12) Calculate ratio of maximum value to minimum value; 13) Set antenna and receiving antenna at reference positions; 14) Set measurement frequency in directly connected state and adjust positions; 15) Calculate ratio of maximum value to minimum value; 16) Calculate total radiation power of wireless device to be measured from. 
     In various embodiments, the radio waves emitted from the tablet or wireless device to be measured are reflected from the anechoic chamber or reverberation chamber and are then concentrated on the receiving antenna, and the total radiated power of the wireless device to be measured is measured. 
     In various embodiments, the method includes creating a criterion that triggers a multi-mode UE to send a measurement report. This can either be periodical or a single event description. 
     In various embodiments, the above method includes a wireless device for obtaining phantom, radio and antenna characteristics for measuring total radiated power. 
     In various embodiments, the tablet or wireless device to be measured is arranged at the position as a complete coupling position based on the phantom, radio and antenna characteristics; the receiving antenna receives the radio waves emitted from the wireless device to be measured; the radiation power of the wireless device to be measured is calculated. 
     In various embodiments, the wireless device or tablet is held in the data communication mode. 
     While one or more embodiments of the have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from their spirit and scope of as defined by the following claims. For example, the steps of the flowcharts of  FIGS. 5, 6, 7, and 10  can be reordered in way that will be apparent to those of skill in the art.