Method for determining voice quality in a telecommunications network

Abstract

A method for determining a quality of voice transmitted by electrical signals between a first telecommunication terminal and a second telecommunication terminal in a telecommunication network, the method comprising: identifying a model type for the first telecommunication terminal and the second telecommunication terminal respectively; identifying at least one operating parameter for the telecommunication network; selecting at least one call aspect (i) of the transmitted voice wherein a quality of the transmitted voice shall be determined for the at least one call aspect; identifying a value of at least one quality parameter (KQI.sub.A/B, i, n) for the at least one call aspect (i) for at least one of the first telecommunication terminal and the second telecommunication terminal as a function of a value of at least one selected engineering parameter (KPI.sub.A/B) of the at least one telecommunication terminal as well as a function of the at least one operating parameter.

Claims

1. A method for determining a quality of voice transmitted by electrical signals between a first telecommunication terminal and a second telecommunication terminal in a telecommunication network, the method comprising: identifying a model type for the first telecommunication terminal and the second telecommunication terminal respectively; identifying at least one operating parameter (n) for the telecommunication network; selecting at least one call aspect (i) of the transmitted voice wherein a quality of the transmitted voice shall be determined for the at least one call aspect; identifying a value of at least one quality parameter (KQI.sub.A/B, i, n) for the at least one call aspect (i) for at least one of the first telecommunication terminal and the second telecommunication terminal as a function of a value of at least one selected engineering parameter (KPI.sub.A/B) of the at least one telecommunication terminal as well as a function of the at least one operating parameter (n) of the telecommunication network; determining a value of an end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal for the at least one call aspect (i) as a function of the identified value of the at least one quality parameter (KQI.sub.A/B, i, n), wherein the value of the end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal represents a quality of the voice transmitted for the call aspect (i) as perceived by a first user (N.sub.A) of the first telecommunication terminal; and determining a value of an end to end quality parameter (KQI.sub.E2E, A/B, i) for the first telecommunication terminal and the second telecommunication terminal (B), wherein determining the end to end quality parameters (KQI.sub.E2E, A/B, i) is performed by selecting an identified value of the quality parameter (KQI.sub.A/B, i, n) so that the end to end quality parameter (KQI.sub.E2E, A/B, i) corresponds to the quality parameter (KQI.sub.A/B, i, n).

2. The method according to claim 1, wherein the call aspect (i) is selected from the group consisting of: echo; double talk (DT); and listening effort.

3. The method according to claim 2, wherein a respective value for the at least one quality parameter (KQI.sub.A/B, i, n) is identified for at least one call aspect (i) for the first telecommunication terminal and the second telecommunication terminal.

4. The method according to claim 3, wherein determining the value of the end to end quality parameter (KQI.sub.E2E, A/B, i) is performed by selecting a value of one of the quality parameters (KQI.sub.A/B, i, n) of one of the first telecommunication terminal and the second telecommunication terminal that represents an inferior quality of the voice transmitted for the at least one call aspect (i) as perceived by the first user (N.sub.A) of the first telecommunication terminal.

5. The method according to claim 4, wherein the call aspect (i) is listening quality objective.

6. The method according to claim 5, wherein identifying the value of the at least one quality parameter (KQI.sub.A/B, i, n) is performed as a function of a respective value of a plurality of engineering parameters (KPI.sub.A/B) wherein at least one engineering parameter (KPI.sub.A/B) is associated with the first telecommunication terminal and the second telecommunication terminal respectively.

7. The method according to claim 6, wherein a value of an end to end quality parameter (KQI.sub.E2E, A/B, i) is determined respectively for plural call aspects (i).

8. The method according to claim 7, further comprising: determining a value of a total call quality (KQI.sub.E2E, G, A/B) from the plurality of values for the end to end quality parameters (KQI.sub.E2E, A/B, i) for one of the first telecommunication terminal and the second telecommunication terminal, wherein the determining is performed by weighted addition of individual values of the end to end quality parameters (KQI.sub.E2E, A/B, i) for the different call aspects (i).

9. The method according to claim 8, wherein values of weighting factors (g.sub.i=1 . . . k), that are used to weight the values of different end to end quality parameters (KQI.sub.E2E, A/B, i) before addition are different for different calls aspect (i).

10. The method according to claim 9, wherein a value of at least one weighting factor (g.sub.i) or of all weighting factors (g.sub.i=1 . . . k) is a function of the value of an associated end to end quality parameter (KQI.sub.E2E, A/B, i), and wherein a relationship between a respective value of the weighting factor (g.sub.i) and the value of the associated end to end quality parameter (KQI.sub.E2E, A/B, i) is non-linear.

11. A non-transitory computer-readable storage medium storing instructions for implementing the method of claim 1 when executed by a processing device.

12. A method for determining a quality of voice transmitted by electrical signals between a first telecommunication terminal and a second telecommunication terminal in a telecommunication network, the method comprising: identifying a model type for the first telecommunication terminal and the second telecommunication terminal respectively; identifying at least one operating parameter (n) for the telecommunication network; selecting at least one call aspect (i) of the transmitted voice wherein a quality of the voice transmitted shall be determined for the at least one call aspect (i); identifying a value of at least one quality parameter (KQI.sub.A/B, i, n) for the at least one call aspect (i) for at least one of the first telecommunication terminal and the second telecommunication terminal as a function of a value of at least one selected engineering parameter (KPI.sub.A/B) of the at least one telecommunication terminal as well as a function of the at least one operating parameter (n) of the telecommunication network; determining a value of an end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal for the at least one call aspect (i) as a function of the identified value of the at least one quality parameter (KQI.sub.A/B, i, n), wherein the value of the end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal represents a quality of the voice transmitted for the call aspect (i) as perceived by a user (N.sub.A) of the first telecommunication terminal; further comprising determining a respective value of an end to end quality parameters (KQI.sub.E2E, A/B, i) for the first and second telecommunication terminals; and determining the end to end quality parameters (KQI.sub.E2E, A/B, i) is performed by selecting the identified value of the quality parameter (KQI.sub.A/B, i, n) so that the end to end quality parameter (KQI.sub.E2E, A/B, i) corresponds to the quality parameter (KQI.sub.A/B, i, n).

13. A method for determining a quality of voice transmitted by electrical signals between a first telecommunication terminal and a second telecommunication terminal in a telecommunication network, the method comprising: identifying a model type for the first telecommunication terminal and the second telecommunication terminal respectively; identifying at least one operating parameter (n) for the telecommunication network; selecting at least one call aspect (i) of the transmitted voice wherein a quality of the voice transmitted shall be determined for the at least one call aspect (i); identifying a value of at least one quality parameter (KQI.sub.A/B, i, n) for the at least one call aspect (i) for at least one of the first telecommunication terminal and the second telecommunication terminal as a function of a value of at least one selected engineering parameter (KPI.sub.A/B) of the at least one telecommunication terminal as well as a function of the at least one operating parameter (n) of the telecommunication network; determining a value of an end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal for the at least one call aspect (i) as a function of the identified value of the at least one quality parameter (KQI.sub.A/B, i, n), wherein the value of the end to end quality parameter (KQI.sub.E2E, A, i) of the first telecommunication terminal represents a quality of the voice transmitted for the call aspect (i) as perceived by a user (N.sub.A) of the first telecommunication terminal; further comprising determining a respective value of an end to end quality parameters (KQI.sub.E2E, A/B, i) for the first and second telecommunication terminals; and determining the end to end quality parameters (KQI.sub.E2E, A/B, i) is performed by selecting the identified value of the quality parameter (KQI.sub.A/B, i, n) so that the end to end quality parameter (KQI.sub.E2E, A/B, i) corresponds to the quality parameter (KQI.sub.A/B, i, n), wherein the identified value of the quality parameter (KQI.sub.A/B, i, n) is stored in a a multi-dimensional matrix residing in a non-transitory computer-readable storage medium.

14. The method according to claim 13, further comprising: determining a respective value of an end to end quality parameters (KQI.sub.E2E, A/B, i) for the first and second telecommunication terminals, wherein determining the end to end quality parameters (KQI.sub.E2E, A/B, i) is performed by selecting the identified value of the quality parameter (KQI.sub.A/B, i, n) so that the end to end quality parameter (KQI.sub.E2E, A/B, i) corresponds to the quality parameter (KQI.sub.A/B, i, n).

15. The method according to claim 13, wherein determining the value of the end to end quality parameter (KQI.sub.E2E, A/B, i) is performed by selecting the value of one of the quality parameters (KQI.sub.A/B, i, n) of one of the first and second telecommunication terminals that represents an inferior quality of the voice transmission for the respective call aspect (i) as perceived by the user (N.sub.A) of the first telecommunication terminal.

16. The method according to claim 13, wherein identifying the value of the at least one quality parameters (KQI.sub.A/B, i, n) is performed as a function of a respective value of a plurality of engineering parameters (KPI.sub.A/B) wherein at least one engineering parameter (KPI.sub.A/B) is respectively associated with each respective telecommunication terminal of the first and second telecommunication terminals.

17. The method according to claim 13, wherein a value of an end to end quality parameters (KQI.sub.E2E, A/B, i) is determined respectively for plural call aspects (i).

18. The method according to claim 17, further comprising determining a value of a total call quality (KQI.sub.E2E, G, A/B) from the plurality of values for the end to end quality parameters (KQI.sub.E2E, A/B, i) for one of the first and second telecommunication terminals, wherein the determining is performed by weighted addition of the individual values of the end to end quality parameters (KQI.sub.E2E, A/B, i) for the different call aspects (i).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The method according to the invention is subsequently described based on an embodiment with reference to drawing figures, wherein

(2) FIG. 1 illustrates a schematic of a call carried out on a telecommunication network; and

(3) FIG. 2 illustrates a flow chart of the method according to the invention for determining a total call quality of the call.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 schematically illustrates a call carried out in a telecommunication network t. A user N.sub.A of the first telecommunication terminal A and a user N.sub.B of a second telecommunication terminal B are participants in a call. FIG. 1 also shows a first router R.sub.A a second router R.sub.B and the telecommunication network t. The transmission of the voice exchanged between the two users N.sub.A, N.sub.B is performed by voice over internet protocol (VoIP).

(5) The voice put out by the user N.sub.A is received by a microphone of the first telecommunication terminal A not illustrated in detail in FIG. 1 and converted into an electrical signal. The electrical signal is digitized and transmitted by the first router R.sub.A in data packets through the internet protocol (IP) to the telecommunication network t. Analogously the voice put out by the user N.sub.B is transmitted by the second router R.sub.B to the telecommunication network t. The voice signals transmitted as data packets are exchanged in the telecommunication network t so that the voice put out by the user N.sub.A is transmitted by the telecommunication network t through the second router R.sub.B by a speaker of the telecommunication terminal B that is not illustrated in detail to FIG. 1 to the user N.sub.B, and in the same manner from the user N.sub.B to the user N.sub.A.

(6) Determining a total call quality KQI.sub.E2E, G, A of the voice transmission perceived by the user N.sub.A of the telecommunication terminal A is performed by the method according to the invention. FIG. 2 illustrates a flow chart of the method steps. Determining the total call quality KQIE2E, .sub.G, A is performed by weighted addition of individual end-to-end quality parameters KQI.sub.E2E, A, i, which were determined for different call aspects.

(7) In a first step of the method according to the invention a model type of the respectively participating telecommunication terminals A, B is identified. Based on the identified model types values of engineering parameters KPI.sub.A/B of the two telecommunication terminals A, B, are interrogated in a second step wherein the values are required for a selected calls aspect i to identify a corresponding quality parameter KQI.sub.A/B, i, n. Interrogating the engineering parameters KPI.sub.A/B is performed through the telecommunication terminals A, B, where the values of the engineering parameters KPI.sub.A/B of the respective telecommunication terminal A, B are stored. However, it is also conceivable that the engineering parameters KPI.sub.A/B are identified from a central data base. In this case the selection of a call aspect i predetermines which of the engineering parameters KPI.sub.A/B of the participating telecommunication terminals A, B, are interrogated.

(8) Additionally at least one operating parameter n of the telecommunication network t is identified, thus values of the operating parameter n of the telecommunication network t are interrogated that are required for the selected call aspect i to identify a corresponding quality parameter KQI.sub.A/B, i, n. In the illustrated embodiment current values of network run time, packet loss and jitter are identified as operating parameters n. It is also conceivable that additional operating parameter n are used to determine the overall call quality KQI.sub.E2E, G, A of the voice transmission.

(9) Based on the identified engineering parameters KPI.sub.A/B and the identified operating parameters n of the telecommunication network t a third step identifies values of the quality parameters KQI.sub.A/B, i, n to identify the quality of the voice transmission with respect to the respective call aspects i. Thus, values of the quality parameters KQI.sub.A/B, i, n are selected which were determined in preceding lab tests under at least similar or identical conditions, this means using at least identical model types of the telecommunication terminals A, B and at least similar operating parameters n of the telecommunication network t. Selecting the values of the quality parameter KQI.sub.A/B, i, n can be performed in particular from a multi-dimensional matrix in which a plurality of values for the different combinations of engineering parameters KPI.sub.A/B and operating parameters n for the different call aspects i is stored.

(10) From the identified quality parameters KQI.sub.A/B, i, n an end to end quality parameter KQI.sub.E2E, A, i is determined in a fourth step. Thus, the first four method steps are performed for a plurality of call aspects I, in particular for “listening quality objective”, “echo”, and “double talk” and “listening effort”. Eventually a total call quality KQI.sub.E2E, G, A of the voice transmission is determined from the entirety of the end to end quality parameters KQI.sub.E2E, A, i, wherein the total call quality is computed by weighted addition of the individual end to end quality parameters KQI.sub.E2E, A, i. When determining the total call quality KQI.sub.E2E, G, A four call aspects i are considered infra.

(11) In a first step the model types of the two telecommunication terminals A, B were identified.

(12) In order to assess the voice received by the user A with respect to the call aspect i “listening quality objective” LQO the transmission sensitivity of the second telecommunication terminal B represented by the engineering parameter KPI.sub.B “sending loudness rating” SLR and the volume setting at the first telecommunication terminal A provided by the engineering parameter KPI.sub.A “receive loudness rating” RLR are used as engineering parameters KPI.sub.A/B for identifying a first quality parameter KQI.sub.A, i=LQO, n. Additionally the current values of the packet loss and of the jitter of the telecommunication network tare identified. The value of a first quality parameter KQI.sub.A, i=LQO, n is identified as a MOS value of 4 based on the previously identified engineering parameters KPI.sub.A/B of the two telecommunication terminals A,B and the identified operating parameters n of the telecommunication network t.

(13) Furthermore an additional quality parameter KQI.sub.B, i=LQO, n namely the sound influence of the second telecommunication terminal B is used for the call aspect i “listening quality objective when identifying the end to end quality parameter KQI.sub.E2E, A, i=LQO. The sound influence describes what the transmission device of the second telecommunication terminal B sound like. Thus, the transmission characteristics of the microphone of the second telecommunication terminal B determines this sound. The value of the quality parameter KQI.sub.B, i=LQO, n is identified as a MOS value of 3.

(14) Determining the end to end quality parameter KQI.sub.E2E, A, i=LQO is performed in the illustrated embodiment by selecting the value of the two quality parameter KQI.sub.A/B, i=LQO, n that predicts inferior quality of voice transmission. Therefore the following applies: KQI.sub.E2E, A, i=LQO=min{KQI.sub.A, i=LQO, n, KQI.sub.B, i=LQO, n}. From the comparison of the preceding quality parameters KQI.sub.A/B, i=LQO, n therefore the quality parameter KQI.sub.B, i=LQO, n that describes the sound influence of the second telecommunication terminal B is used for determining the end to end quality parameter KQI.sub.E2E, A, i=LQO. The result of the end to end quality parameter KQI.sub.E2E, A, i=LQO is therefore a MOS value of 3.

(15) An echo that is perceived by the user N.sub.A of the first telecommunication terminal A is caused by the second telecommunication terminal B. For the call aspect i “echo” E with reference to the user N.sub.A of the first telecommunication terminal A the transmission sensitivity of the first telecommunication terminal A represented by the engineering parameter KPI.sub.A “sending loudness rating” SLR, and the volume settings at both telecommunication terminal A, B represented by the engineering parameters KPI.sub.A, KPI.sub.B receive loudness rating RLR are used as engineering parameters KPI.sub.A/B for identifying a quality parameter KQI.sub.A, i=E, n. Furthermore the run time of the first telecommunication terminal A, the round trip delay is identified as engineering parameter KPI.sub.A and the current value of the network run time of the telecommunication network t is identified as operating parameter n. An echo run time is estimated from the run time of the first telecommunication terminal A and the network run time of the telecommunication network t. Based on the identified engineering parameters KPI.sub.A/B of the two telecommunication terminals A, B and the condition of the telecommunication network t, the quality parameter KQI.sub.A, i=E, n, which is also identified as end to end quality parameter, KQI.sub.E2E, A, i=E is identified as a MOS value of 4.

(16) The quality of the voice transmission perceived by the user N.sub.A of the first telecommunication terminal A with respect to the call aspect i “double talk” DT is also significantly influenced by the second telecommunication terminal B. In order to determine a quality parameter KQI.sub.B, i=DT, n the transmission sensitivity of the first telecommunication terminal A, represented by the engineering parameter KPI.sub.A “sending loudness rating” SLR, and the reproduction volumes of the two telecommunication terminals A, B provided by the engineering parameter KPI.sub.A, KPI.sub.B “receive loudness rating” RLR are used. Furthermore the run time of the first telecommunication terminal A, the Roundtrip-Delay, is used as engineering parameter KPI.sub.A and the current value of the network run time of the telecommunication network t is used as an operating parameter n and the run time of the second telecommunication terminal B, the Roundtrip-Delay, is identified as engineering parameter KPI.sub.B. When using the participating telecommunication terminals A, B and for a given condition of the telecommunication networks t the quality parameter KQI.sub.B, i=DT, n, which is also identified as an end to end quality parameter KQI.sub.E2E, A, i=DT can be identified as MOS value of 5.

(17) The preceding identification of the end to end quality parameter KQI.sub.E2E, A, i=DT is valid under the presumption that no interference, e.g. caused by the signal processing in the first telecommunication terminal A is added in the receiving direction of the first telecommunication terminal A, and that the telecommunication network does not cause any additional degradation of the double talk properties, e.g. by a attenuation control or by an echo compensation. In case the described degradations are present the influences can be considered by identifying additional quality parameters KQI.sub.A, i=T, n when determining the end to end quality parameters KQI.sub.E2E, A, i=DT.

(18) In order to assess the call aspect i “listening effort” LE for the user N.sub.A of the first telecommunication terminal A, the transmission sensitivity of the second telecommunication terminal B provided by the engineering parameter KPI.sub.B “sending loudness rating” SLR and the volume setting at the first telecommunication terminal A, provided by the engineering parameter KQI.sub.A, “receive loudness rating” RLR are used to identify the suitable quality parameter KPI.sub.A i=LE, n. Furthermore the level of the background noise at the location of the first telecommunication terminal A, is determined in time periods without voice, however it is also conceivable to estimate the background noise level base on the typical application of the telecommunication terminal A. In the instant case the quality parameter KQI.sub.A, i=LE, n is identified as MOS value of 4. The MOS value also represents the end to end quality parameter KQI.sub.E2E, A, LE.

(19) Determining the total call quality KQI.sub.E2E, G, A is eventually performed by adding the end to end quality parameters KQI.sub.E2E, A, i of the four call aspects i. Presuming that the individual call aspects i influence the total call quality KQI.sub.E2E, G, A differently, the values of the individual end to end quality parameters KQI.sub.E2E, A, i are respectively weighted with a weighting factor g.sub.i before addition. The value of the weighting g.sub.i is a function of an identified value of the individual end to end quality parameter KQI.sub.E2E, A, I, wherein the weighting factors g.sub.i with reference to the end to end quality parameter KQI.sub.E2E, A, i do not change in a linear manner in the illustrated embodiment. For the call aspects i “echo” E, “double talk” DT and “listening effort” LE the values of the respective end to end quality parameters are respectively weighted with a weighting factor of 0.25. Since the end to end quality parameter KQI.sub.E2E, A, i=LQO of the call aspect i “listening quality objective” (LQO) was only identified as MOS value of 3 the value of the corresponding weighting factor g.sub.i is 0.1. Thus, the value of the overall call quality KQI.sub.E2E, G, A can be determined as a MOS value of 3.55.

(20) The total call quality KQI.sub.EZE, G,B for the user N.sub.B of the second telecommunication terminal B can be determined in the same way.

(21) A non-transitory computer-readable storage medium storing instructions for implementing a method for determining a quality of voice transmitted by electrical signals between a first telecommunication terminal (A) and a second telecommunication terminal (B) in a telecommunication network (t), when executed by a processing device.

(22) The data used in the embodiments of the present invention may be stored and/or recalled from a non-transitory computer-readable storage medium. For example, the identified value of the quality parameter (KQI.sub.A/B, i, n) maybe stored in a multi-dimensional matrix residing in a non-transitory computer-readable storage medium. Other data may be similarly stored and/or recalled.

REFERENCE NUMERALS AND DESIGNATIONS

(23) A first telecommunication terminal B second telecommunication terminal N.sub.A user of the first telecommunication terminal N.sub.B user of the second telecommunication terminal R.sub.A first router R.sub.B second router t telecommunication network i call aspect n operating parameter of telecommunication network KPI.sub.A/B engineering parameter KQI.sub.A/B, i, n quality parameter KQI.sub.E2E, A/B, I end to end quality parameter KQI.sub.E2E, G, A/B total call quality LQO call aspect “listening quality objective” E call aspect “Echo” DT call aspect “double talk” LE call aspect “listening effort” SLR engineering parameter “sending loudness rating” RLR engineering parameter “receive loudness rating”