Abstract:
A technique is discloses that enables a first telecommunications terminal, wireless or otherwise, to report to its user whether a second, wireless telecommunications terminal is receiving the first terminal&#39;s packet stream transmissions at a satisfactory quality level. The second terminal receives the packet stream that conveys the media waveform transmitted by the first terminal. The media waveform can be that of the speech signal of the first terminal&#39;s user. The second terminal measures a trait of the received signal and encodes the measurement data into the packet stream that the second terminal is already transmitting to the first terminal. The first terminal then decodes the measurement data from the received second stream and presents, to its user, a quality indication that is based on the measurement data. In doing so, the first terminal provides its user with a better idea of whether the second terminal has reliably received the user&#39;s communication.

Description:
PRIORITY 
       [0001]    This continuation application claims priority to U.S. Non-provisional application Ser. No. 12/207,219, filed Sep. 9, 2008, the contents of which are herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to telecommunications in general, and, more particularly, to verifying whether a signal that has been transmitted by a first telecommunications terminal has been satisfactorily received by a second, wireless telecommunications terminal. 
       BACKGROUND OF THE INVENTION 
       [0003]    When people communicate with each other over a distance, there is often uncertainty as to whether the participants hear each other. The uncertainty can be attributed to noise or other forms of impairment that are present in the transmission path between the participants. The uncertainty in achieving successful communication is not specific to any one form of communication. This is evident, for example, in two-way radio communication for military, aerospace, or public service purposes, in which the participants are often forced to repeat what was heard. Additionally, in order to acknowledge and confirm the accuracy of the communication explicitly, the participants often have to use words such as “roger” to indicate that information has been received or “copy” to indicate that what was just said is understood. Even in cellular telecommunications, which comprises an adapted form of two-way radio communication, commercials and advertisements by the cellular service providers often feature themes of anxiety caused by a cell phone user not hearing someone else or of a service rep continually asking on his cell phone if someone else is able to hear him. 
         [0004]    As alluded to above, radio communication is particularly vulnerable to impairments, which can come in the form of co-channel interference, Rayleigh fading, thermal noise, and so forth. Often, there is only one person who is using a wireless phone on a call, the other person being on a landline phone such as an office deskset. Increasingly, however, a call that involves a first wireless phone user will also involve a second wireless phone user. The scenario of two wireless phones can involve a cell phone and WiFi device, two cell phones, two WiFi devices, and so forth. 
         [0005]    A wireless user often has some kind of signal strength indication that is typically based on measurements of a received signal&#39;s strength, which indication is then displayed at the phone. Sometimes, however, the indication suggests that a service provider&#39;s coverage area is better than it actually is. This can occur, for example, when a service provider boosts the power that is transmitted by the serving base station over the downlink to a wireless phone, leading a wireless user to think that the call quality is good, even though the carrier-to-impairment ratio of the downlink might still be unsatisfactory. In any event, the corresponding uplink might turn out to be far weaker or noisier, and so the wireless user does not know with any reasonable certainty whether the far-end party is hearing what is being said. Furthermore, if there are two wireless terminals involved in the call (i.e., one for each party), the first party really has only a rough idea, and probably an unreliable one, of what the far-end party is receiving, based on the displayed signal-strength indication. 
         [0006]    Not surprisingly, a lot of effort has been spent on improving the robustness of communications and ensuring each participant in a conversation that the other person is, in fact, hearing him. In a Voice over Internet Protocol context, for example, protocols such as Real-time Transport Control Protocol (RTCP) have been developed to deal with improving the robustness of communication, among other things. RTCP in particular provides out-of-band control information for a Real-time Transport Protocol (RTP) packet stream that conveys voice or other media information between terminals. The receiving terminal of a packet stream can transmit RTCP packets back to the transmitting terminal, in order to report the quality of service being experienced by the receiving terminal. However, this is disadvantageous because it requires either additional standardization across terminals or additional transmission infrastructure, or both. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention enables a first telecommunications terminal, wireless or otherwise, to report to its user whether a second, wireless telecommunications terminal is receiving the first terminal&#39;s packet stream transmissions at a satisfactory quality level. In accordance with the illustrative embodiment of the present invention, the second terminal receives the packet stream that conveys the media waveform transmitted by the first terminal. For example, the media waveform can be that of the speech signal of the first terminal&#39;s user. The second terminal measures a trait of the received signal and encodes the measurement data into the packet stream that the second terminal is already transmitting to the first terminal, the packet stream from the second terminal conveying its user&#39;s speech signal. The first terminal then decodes the measurement data from the received second stream and presents, to its user, a quality indication based on the decoded data. Since the quality indication is based on the signal received at the second terminal from the first terminal, instead of being based just on the received signal strength as measured by the first terminal, the first terminal&#39;s user has a better idea of whether the second terminal has reliably received the user&#39;s communication. 
         [0008]    In some embodiments, the second terminal, as it receives the packet stream of data transmitted by the first terminal, can perform speech-to-text conversion of the reconstructed speech waveform that is conveyed by the packet stream. Based on the measurement data already generated, the second terminal can then package the converted text, or some part of that text, into a text-based message, such as an SMS message, and transmit the text-based message back to the first terminal. The first terminal then displays the text-based message, thereby enabling its user to determine if what the user has recently spoken has been reliably received by the second terminal. 
         [0009]    The invention is based on the idea that if the user of the first terminal is provided with an idea of the signal quality that is present in the radio link at the second terminal, or with information that is affected by that signal quality, then the user has a better idea of whether his speech has been reliably received at the second terminal. In accordance with the illustrative embodiment, the same idea is simultaneously applied in the opposite direction as well, in which the first terminal measures a received signal that conveys a packet stream of a speech waveform from the second terminal, and provides measurement data back to the second terminal and the second terminal&#39;s user. 
         [0010]    The illustrative embodiment of the present invention features a first telecommunications terminal that comprises: a transmitter interface that transmits, to a second wireless terminal, a first packet stream that conveys a media waveform a(t), which is originated by a user of the first telecommunications terminal; a receiver interface that receives, from the second wireless terminal, a second packet stream into which the second wireless terminal has encoded a first set of one or more measurements of a first predetermined trait of a signal received by the second wireless terminal, the signal representing at least a portion of media waveform a(t); a processor that i) decodes the first set of one or more measurements from the second packet stream and ii) adjusts the value of a predetermined quality indication based on the first set of one or more measurements decoded; and a user interface that presents status that is based on the value of the predetermined quality indication. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  depicts a block diagram of the salient components of telecommunications system  100 , in accordance with the illustrative embodiment of the present invention. 
           [0012]      FIG. 2  is a block diagram of the salient components of wireless terminal  101 - m,  in accordance with the illustrative embodiment of the present invention. 
           [0013]      FIG. 3  depicts a diagram of the salient messages and tasks that are related to exchanging packet streams, as well as to exchanging measurement information of one or more traits of signals that convey those packet streams, in accordance with the illustrative embodiment of the present invention. 
           [0014]      FIG. 4  depicts how terminals  101 - 1  and  101 - 2  perform the tasks that were performed by terminals  101 - 2  and  101 - 1 , respectively, in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIG. 1  depicts a block diagram of the salient components of telecommunications system  100 , in accordance with the illustrative embodiment of the present invention. System  100  comprises telecommunications terminals  101 - 1  and  101 - 2 , base stations  102  and  103 , and telecommunications transmission network  104 , interconnected as shown. Although the system of the illustrative embodiment comprises two wireless terminals, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that comprise any number of telecommunications terminals  101 - 1  through  101 -M, wherein M is a positive integer. 
         [0016]    Telecommunications terminal  101 - m,  where m has a value between 1 and M (and where M is equal to two in the illustrative embodiment) is a device that enables its user to communicate with the user of another telecommunications terminal. To this end, terminal  101 - m  digitizes and encodes a source signal, such as a person&#39;s voice or other type of media waveform, transmits the encoded signal to the other terminal, and concurrently receives and decodes a waveform that is being transmitted by the other terminal. The encoded source signals are exchanged in the form of streams of data packets. Depending on the data communications protocol involved, a packet is sometimes referred to as a “frame.” 
         [0017]    When terminal  101 - m  is “wireless,” it exchanges packet streams with a far-end device by communicating directly and wirelessly with a base station, such as base stations  102  and  103 , on an electromagnetic-frequency link that has been provisioned to the call. Terminal  101 - m  can be a WiFi handset, a cellular telephone, a cordless telephony (CT) device with a signal measurement capability, a notebook computer relying on a wireless LAN, a personal digital assistant (PDA) with a wireless interface, or any other type of device whose direct link with the greater network (i.e., network  104 ) is over-the-air. Terminals  101 - 1  and  101 - 2 , as well as additional wireless terminals if present, can be identical to or different from each other; for example, terminal  101 - 1  can be a WiFi handset and terminal  101 - 2  can be a cell phone. In some embodiments, a wireless telecommunications terminal communicates with another wireless terminal, while in some alternative embodiments, the wireless terminal communicates with a wired telecommunications terminal. Examples of a wired terminal include a plain old telephone service (POTS) deskset, an IP deskset plugged into a wired LAN, a softphone on a personal computer plugged into a wired LAN, etc.). 
         [0018]    Terminal  101 - m &#39;s salient components are described below and with respect to  FIG. 2 , and the salient tasks performed by terminal  101 - m  are described with respect to  FIGS. 3 and 4 . It will be clear to those skilled in the art, after reading this specification, how to make and use wireless telecommunications terminal  101 - m.    
         [0019]    Base stations  102  and  103  communicate directly via radio link with terminals  101 - 1  and  101 - 2 , respectively. The base stations provide connectivity, for their served wireless terminals, to the rest of telecommunications system  100 . Specifically, base station  102  receives signals from terminal  101 - 1  via uplink path  110 -A and transmits signals to terminal  101 - 1  via downlink path  110 -B, in well-known fashion. Similarly, base station  103  receives signals from terminal  101 - 2  via uplink path  120 -A and transmits signals to terminal  101 - 2  via downlink path  120 -B, in well-known fashion. 
         [0020]    Base stations  102  and  103  can be part of the same service provider&#39;s network or they can be situated in different networks. Furthermore, depending on the types of wireless terminals they serve, base stations  102  and  103  can communicate by using the same wireless protocol (e.g., CDMA, GSM, UMTS, DECT, WiFi, etc.) or can communicate by using different wireless protocols. In any event, it will be clear to those skilled in the art how to make and use base stations  102  and  103 . 
         [0021]    Telecommunications transmission network  104  is a network that transports the packet streams associated with calls between two or more telecommunications terminals. Each packet stream can comprise voice, video, and so forth. In accordance with the illustrative embodiment, network  104  comprises packet-switched infrastructure. However, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which network  104  comprises:
       i. the Public Switched Telephone Network (PSTN), or   ii. the Internet, or   iii. one or more other telecommunications networks, or   iv. any combination of i, ii, and iii.
 
Furthermore, as those who are skilled in the art will appreciate, network  104  can comprise speech transcoders or other types of transcoders, as are known in the art, in order to convert from one type of data representation to another. For example, packets of speech-encoded data might be converted to time-division-multiplexed (TDM) format, the reformatted data then being assigned to a virtual circuit time slot and transported across part of the network in the TDM format.
       
 
         [0026]      FIG. 2  is a block diagram of the salient components of wireless terminal  101 - m  in accordance with the illustrative embodiment of the present invention, which components are interconnected as shown. In accordance with the illustrative embodiment, wireless terminal  101 - m  comprises:
       i. receiver interface  201 ,   ii. transmitter interface  202 ,   iii. processor  203 ,   iv. memory  204 ,   v. display  205 ,   vi. loudspeaker  206 , and   vii. vibration mechanism  207 .
 
It will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which wireless terminal  101 - m  comprises any subcombination of the components listed above.
       
 
         [0034]    Receiver interface  201  and transmitter interface  202  comprise the circuitry that enables terminal  101 - m  to respectively receive signals from and transmit signals to the associated base station, in well-known fashion. In accordance with the illustrative embodiment, terminal  101 - m  receives and transmits media waveform signals that are encoded via the ITU G.729 standard and represented in Voice over Internet Protocol (VoIP) packet streams of data, in well-known fashion. As those who are skilled in the art will appreciate, in some alternative embodiments terminal  101 - m  receives and transmits media waveform signals that are encoded and/or represented in a different format. 
         [0035]    Receiver interface  201  further comprises the circuitry that enables terminal  101 - m  to generate signal measurements, in well-known fashion, of one or more traits of electromagnetic signals that it receives from its serving base station, as well as possibly from other electromagnetic signal sources such as other base stations, commercial television transmitters, commercial radio transmitters, navigation transmitters, ground-based aviation transmitters, and so forth. 
         [0036]    Processor  203  is a general-purpose processor that is capable of receiving information from receive interface  201 , of executing instructions stored in memory  204 , of reading data from and writing data into memory  204 , and of transmitting information to transmit interface  202 . Additionally, processor  203  is able to provide signals to display  205 , loudspeaker  206 , and vibration mechanism  207 . In some alternative embodiments of the present invention, processor  203  might be a special-purpose processor instead of a general-purpose processor. 
         [0037]    Processor  203  is further capable of encoding signal measurements into the packet stream that is intended for another terminal. Processor  203  is also capable of decoding, from a received packet stream, information that is related to signal measurements as provided by another terminal. In some embodiments, processor  203  is also capable of speech-to-text conversion into a text string of a speech waveform that it receives from another terminal during a call. 
         [0038]    Memory  204  stores the instructions and data used by processor  203 , in well-known fashion. Memory  204  can be any combination of dynamic random-access memory (RAM), flash memory, disk drive memory, and so forth. 
         [0039]    Display  205  is part of the user interface of terminal  101 - m.  In accordance with the illustrative embodiment, display  205  comprises a liquid crystal display that is able to present the terminal&#39;s user with a visual representation of status. It will be clear to those skilled in the art how to make and use alternative embodiments of the present invention in which display  205  comprises a display that is other than liquid crystal-based. In any event, it will be clear to those skilled on the art how to make and use display  205 . 
         [0040]    Loudspeaker  206  is another part of the user interface of terminal  101 - m.  In accordance with the illustrative embodiment, loudspeaker  206  is able to present the terminal&#39;s user with an audible representation of status. As those who are skilled in the art will appreciate, in some alternative embodiments of terminal  101 - m,  loudspeaker  206  can instead be a type of electro-acoustic transducer other than a loudspeaker, such as an earpiece. In any event, it will be clear to those skilled on the art how to make and use loudspeaker  206 . 
         [0041]    Vibration mechanism  207  is yet another part of the user interface of terminal  101 - m.  In accordance with the illustrative embodiment, mechanism  207  is able to present the terminal&#39;s user with a tactile representation of status. It will be clear to those skilled on the art how to make and use vibration mechanism  207 . 
         [0042]    In accordance with the illustrative embodiment, one or more components of terminal  101 - m  perform the tasks described below and with respect to  FIGS. 3 and 4 . As those who are skilled in the art will appreciate, the described tasks can be performed by different combinations of terminal  101 - m &#39;s components, across various embodiments of the present invention. 
         [0043]      FIG. 3  depicts a diagram of the salient messages and tasks that are related to exchanging packet streams, as well as to exchanging measurement information of one or more traits of signals that convey those packet streams, in accordance with the illustrative embodiment of the present invention. As those who are skilled in the art will appreciate, some of the messages and tasks that appear in the diagram can be performed in parallel or in a different order than that depicted. Moreover, those who are skilled in the art will further appreciate that in some alternative embodiments of the present invention, only a subset of the depicted messages and tasks are performed. 
         [0044]    As depicted in  FIG. 3 , wireless terminals  101 - 1  and  101 - 2  are exchanging packet streams of data, each of which represents a media waveform, as part of a two-way call with each other. In accordance with the scenario, terminals  101 - 1  and  101 - 2  exchange digitized waveforms of their user&#39;s voices. However, as those who are skilled in the art will appreciate, in other scenarios, two or more terminals can exchange other types of media, in accordance with the techniques described herein. Furthermore, in some alternative embodiments, a wireless terminal can exchange packet streams of data with a wired terminal; in the process, the wireless terminal can generate signal measurements with respect to the signal received from the wired terminal and can then transmit representations of those measurements back to the wired terminal. 
         [0045]    As part of a call, terminal  101 - 1  transmits packet stream  301  to terminal  101 - 2 , which packet stream conveys a first media waveform a(t), which is a representation of the voice of terminal  101 - 1 &#39;s user during the call. 
         [0046]    Terminal  101 - 2  receives packet stream  301  and, at task  302 , generates a first set of one or more signal measurements of one or more traits of a signal that it receives from base station  103 , the signal conveying a representation of waveform a(t). In some embodiments, terminal  101 - 2  also generates measurements of one or more traits of signals that are received from one or more additional transmitters. 
         [0047]    In accordance with the illustrative embodiment, each set of measurements comprises measurement data of one or more of the following signal traits of signals received from one or more transmitters (e.g., base stations  102  and  103 , commercial television, commercial radio, navigation, ground-based aviation, etc.):
       i. the received signal strengths of signals received by terminal  101 - 2 ; and   ii. the received signal-to-impairment ratios of signals received by terminal  101 - 2 ; and   iii. the bit-error rate (BER) or frame-error rate (FER) of signals received by terminal  101 - 2 ; and   iv. the path-losses of signals received by terminal  101 - 2 ; and   v. the received temporal difference of each pair of multipath components of signals received by terminal  101 - 2 ; and   vi. the received delay spreads of signals received by terminal  101 - 2 ; and   vii. the received relative arrival times of two or more multipath components of signals received by terminal  101 - 2 ; and   viii. the round-trip time of signals transmitted and received by terminal  101 - 2  through one or more base stations.       
 
         [0056]    As those who are skilled in the art will appreciate, in some embodiments base station  103  can generate measurement data in the uplink direction of one or more of the traits listed above of signals that the base station receives, and can then make available those measurements to terminal  101 - 2 , or to terminal  101 - 1  for that matter. 
         [0057]    Terminal  101 - 2 , at task  303 , then encodes the first set of one or more signal measurements into a second packet stream that conveys a media waveform b(t), namely packet stream  304 , and transmits the packet stream to terminal  101 - 1 . The waveform b(t) is originated by a user of terminal  101 - 2  and represents, for example, the user&#39;s voice. In some embodiments, the encoding is based on the values of the measurements; for example, if the signal measurement is at a satisfactory level, then encoding and transmission of the measurements might be unnecessary and might not be performed. 
         [0058]    As those who are skilled in the art will appreciate, there are various ways to encode the measurement data into the packet stream. For example, a representation of the measurement data can be mixed into the media waveform as a low-volume and/or high-pitch signal. As another example, U.S. application Ser. No. 11/675,345, filed on Feb. 15, 2007 and incorporated herein by reference, discloses the transmission of a digital message (e.g., measurement data, etc.) along with a corresponding media waveform, without adding any additional bits to the packet stream that conveys the waveform. Based on an evaluation of the perceptual significance of each digitized bit of the media waveform, the technique disclosed in the referenced application: (i) determines which digitized bits can be overwritten; and (ii) intersperses the digital message bits throughout the digitized waveform in place of the over-writeable bits. 
         [0059]    In some alternative embodiments, terminal  101 - 2  might instead encode the measurement data into another type of conveyance, such as into one or more SMS messages, before transmitting the measurement data to terminal  101 - 1 . 
         [0060]    In some embodiments, at task  307 , terminal  101 - 2  analyzes the received representation of waveform a(t) and performs speech-to-text conversion on the waveform, in well-known fashion, thereby converting the waveform into a text string. Then, terminal  101 - 2  transmits text-based message  308  to terminal  101 - 1 , which message conveys the text string. As those who are skilled in the art will appreciate, after reading this specification, i) the speech-to-text conversion can be invoked based on one or more values of the first set of one or more signal measurements generated, or ii) the transmission of the text-based message can be performed based on one or more values of the first set of one or more signal measurements generated, or both. In some embodiments, the text string comprises N characters converted from the more recently-received portion of the speech waveform a(t), where Nis a positive integer and can be based on an operator-imposed limit on the number of characters transmitted per message. 
         [0061]    Meanwhile, at task  305  terminal  101 - 1  receives packet stream  304 , and decodes the first set of one or more measurements from the second packet stream. Alternatively, if terminal  101 - 2  has transmitted the measurement data via other means, terminal  101 - 1  decodes the data from the other type of conveyance. 
         [0062]    At task  306 , terminal  101 - 1  adjusts the value of a predetermined quality indication, based on the first set of one or more signal measurements decoded at task  305 . In some embodiments, the adjustment can also be based on measurements that terminal  101 - 1  itself generates or obtains of one or more predetermined traits of one of more signals that the terminal receives, such as from base station  102 . Those possible traits and signal sources are described above and with respect to task  302 . Terminal  101 - 1  then presents status to the user of terminal  101 - 1 , wherein the status is based on the value of the predetermined quality indication. 
         [0063]    The method of presentation to terminal  101 - 1 &#39;s user (e.g., visual, audible, tactile, etc.), in some embodiments, depends on the value of the quality indication as adjusted at task  306 . Furthermore, in some other embodiments, the method of presentation to the user depends on the audio mode in which the user operates terminal  101 - 1  (e.g., with a handset, with a headset, with a speaker, etc.). For example, if the user operates terminal  101 - 1  using an audio mode in which the terminal is held close to the ear, it might be more effective to provide a tactile sensation to the user for the purpose of providing the quality status. As those who are skilled in the art will appreciate, the presentation method can be based on a combination of the quality indication value, the audio mode, and other characteristics of terminal  101 - 1 , the user, the call, and/or the information exchanged between terminals. 
         [0064]    If the presentation method is visual, display  205  can render the value of the quality indication in one or more of a variety of formats, such as by using different numbers, different colors, different numbers of bars, smiley face/frowning face icons, and so forth. 
         [0065]    In some embodiments, terminal  101 - 1  adjusts the number of bits transmitted per unit time in packet stream  301  going forward, based on the measurement data received from terminal  101 - 2  and decoded, or obtained by terminal  101 - 1  itself, at task  305 . For example, if the measurement data appear to be favorable, the number of bits transmitted to terminal  101 - 2  might be decreased with little or no effect in waveform quality—for example, by changing the speech encoding (i.e., vocoding) process. As those who are skilled in the art will appreciate, the decision to increase or decrease the number of bits transmitted, as well as by how much, can depend on other factors as well. 
         [0066]    At task  309 , in those embodiments in which terminal  101 - 2  has transmitted text-based message  308 , terminal  101 - 1  receives and displays message  308  in well-known fashion. The user of terminal  101 - 1  is able to examine the contents of the message to see if what she has recently spoken has been reliably received by terminal  101 - 2 . 
         [0067]    Throughout the duration of the call, terminals  101 - 1  and  101 - 2  continually perform the tasks and exchange the messages described with respect to  FIG. 3 . Furthermore, in some embodiments, terminals  101 - 1  and  101 - 2  perform each other&#39;s roles. In other words, as depicted in  FIG. 4 , terminal  101 - 1  performs the tasks that were performed by terminal  101 - 2  in  FIG. 3 , and terminal  101 - 2  performs the tasks that were performed by terminal  101 - 1  in  FIG. 3 . This reflected by packet stream  401 , which conveys media waveform b(t), being transmitted by terminal  101 - 2 , terminal  101 - 1  at task  402  generating signal measurements of the signal conveying waveform b(t) received through base station  102 , and so forth, where tasks  401  through  409  correspond to tasks  301  through  309 , respectively. 
         [0068]    As those who are skilled in the art will appreciate, after reading this specification, the wireless terminal of the illustrative embodiment can exchange packet streams, as well as analyze the waveform content of those packet streams, as part of a three-way call. In a three-way call (e.g., involving terminals  101 - 1 ,  101 - 2 , and  101 - 3 , etc.), at least one terminal, such as terminal  101 - 1 , exchanges packet streams with two other terminals, such as terminals  101 - 2  and  101 - 3 . In that case, terminal  101 - 1  would perform the techniques of the illustrative embodiment both on the packet streams associated with terminal  101 - 2 , as described earlier, and on the packet streams associated with terminal  101 - 3 . 
         [0069]    It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims.