| 1. |
- Rohani, Behrooz, et al.
(författare)
-
Adaptive Control of Perceptual Speech Quality in Modern Wireless Networks
- 2007
-
Konferensbidrag (refereegranskat)abstract
- The speech quality in modern wireless networks has been traditionally measured by metrics which are derived from radio link measurements. The indirect measurement of speech quality based on such metrics is unreliable and often precious network resources are sacrificed to make up for this. In this paper, a perceptual metric is considered for direct measurement of speech quality and the framework for adaptive control of the perceptual speech quality is presented.
|
|
| 2. |
- Rohani, Behrooz, et al.
(författare)
-
An Efficient Method for Perceptual Evaluation of Speech Quality in UMTS
- 2005
-
Konferensbidrag (refereegranskat)abstract
- In this paper we propose an efficient method for perceptual evaluation of speech quality in Universal Mobile Telecommunication System (UMTS). With this method, the network operators are no longer limited to the narrow set of tested system parameters available in the standards. Instead, they can modify system parameters to what they desire, e.g. different Frame Erasure Rates (FER), and the resulting impact on speech quality can be evaluated in a fraction of time as compared with corresponding subjective listening tests. An example case study where the system FER is allowed to increase to 10% is presented.
|
|
| 3. |
- Rohani, Behrooz, et al.
(författare)
-
Benefits of Perceptual Speech Quality Metrics in Modern Cellular Systems
- 2006
-
Ingår i: Electronics Letters. - London : IEE. - 0013-5194 .- 1350-911X. ; 42:21, s. 1250-1251
-
Tidskriftsartikel (refereegranskat)abstract
- Advanced algorithms have become available in recent years that can reliably measure the speech quality as “perceived” by humans. The benefits of applying the perceptual quality measures obtained using these algorithms in the Outer Loop Power Control (OLPC) of Third Generation Universal Mobile Telecommunication System (3G UMTS) are studied in this letter. It is shown that 20% capacity improvement compared to the use of conventional measures can be achieved while an adequate and uniform speech quality is maintained.
|
|
| 4. |
- Rohani, Behrooz, et al.
(författare)
-
Capacity Evaluation of Perceptual-Based Power Control in Mobile Radio Systems
- 2007
-
Konferensbidrag (refereegranskat)abstract
- This paper evaluates the potential capacity improvements in mobile radio systems due to perceptual-based power control. It builds on our previous work on the application of a Real-time Perceptual Speech Quality Metric (RTPSQM) in power control. Encouraged by the performance improvements offered with perceptual-based power control, this paper investigates on how gains in average transmitter power and SIR target translate to gains in the actual capacity in the Global System for Mobile communication (GSM) and the Universal Mobile Telecommunication System (UMTS). In particular, capacity improvements in terms of number of users per cell between 25% to 91% are obtained for perceptual-based power control in GSM. As for UMTS, the results show an increase in Erlang capacity per cell by at least 10%.
|
|
| 5. |
- Rohani, Behrooz, et al.
(författare)
-
Combined AMR Mode Adaptation and Fast Power Control for GSM Phase 2
- 2005
-
Konferensbidrag (refereegranskat)abstract
- The conventional power control of Global System for Mobile communications (GSM) with a control interval of 480 ms is often too slow to react to fast channel variations encountered at even moderate vehicular speeds. As a result, the delivered voice quality can be degraded or unnecessarily high transmission power can be used. In the second case, the excess interference caused due to unnecessarily high transmission power can reduce the network capacity. Although the Adaptive Multi-Rate (AMR) speech codec has been proposed for GSM phase 2+, its application has been considered independently of power control. In this paper, an algorithm is proposed that jointly controls the AMR rate and transmitter power. Computer simulation results are presented that show that the proposed scheme can reduce transmission power by at least 2.5 dB as compared with its counterpart.
|
|
| 6. |
- Rohani, Behrooz, et al.
(författare)
-
Feedback Method for Real-time Perceptual Quality Estimation
- 2004
-
Ingår i: Electronics Letters. - : IEE. - 0013-5194 .- 1350-911X. ; 40:14, s. 913-914
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a feedback scheme for real-time estimation of perceptual speech quality is proposed. The feedback information indicates the quality of each previously received speech frame as “good” or “bad”. This information is used in conjunction with the PESQ algorithm to estimate the received speech quality accurately.
|
|
| 7. |
- Rohani, Behrooz, et al.
(författare)
-
Monitoring of In-Service Perceptual Speech Quality in Modern Cellular Radio Systems
- 2008
-
Konferensbidrag (refereegranskat)abstract
- A method for in-service monitoring of the end-user perceptual speech quality in modern cellular radio systems is proposed. This method incorporates the perceptual evaluation of speech quality (PESQ) algorithm to monitor the quality experienced by the end-user. Here, the monitoring is carried out at the transmitting side. In this case, the speech signal received by the end-user is approximated at the transmitter in accordance with a feedback signal. The performance of the proposed scheme has been investigated through extensive computer simulations for the Universal Mobile Telecommunication System (UMTS) using different speech coding rates and channel conditions. The results indicate that the proposed scheme can predict the end-user quality with a root-mean-squared error (RMSE) of at most 0.15 using the mean opinion score (MOS) rating scheme. Such accuracy can be beneficial in applications such as network maintenance and radio resource management for satisfying desired level of quality of service.
|
|
| 8. |
- Rohani, Behrooz, et al.
(författare)
-
On In-service Perceptual Speech Quality Monitoring in Cellular Radio Systems
- 2009
-
Konferensbidrag (refereegranskat)abstract
- A method for in-service monitoring of the end-user perceptual speech quality in cellular radio systems is proposed. This method incorporates the perceptual evaluation of speech quality (PESQ) algorithm to monitor the quality experienced by the end-user. Here, the monitoring is carried out at the transmitting side. In this case, the speech signal received by the end-user is estimated at the transmitter in accordance with a feedback signal. The performance of the proposed scheme has been investigated through extensive simulations for the Universal Mobile Telecommunication System (UMTS) using different speech coding rates and channel conditions. The results indicate that the proposed scheme can predict end-user quality with a root-mean-squared error (RMSE) of at most 0.15 using the mean opinion score (MOS) rating scheme. Such accuracy can be beneficial in applications such as radio resource management for satisfying the desired level of quality of service.
|
|
| 9. |
- Bayley, Todd, et al.
(författare)
-
Call Quality Monitoring for VoIP
- 2011
-
Konferensbidrag (refereegranskat)abstract
- A method of monitoring the speech quality of a Voice-over-IP call is described in this paper. This method is attractive because it employs the ITU-T standard P.862 for Perceptual Evaluation of Speech Quality which is well-known for its accuracy. In addition, with the proposed method, call quality is monitored without interfering with the call while it is in progress. The results corresponding to an implementation of this method shows call quality can be measured with excellent accuracy under typical network delays.
|
|
| 10. |
- Rohani, Bijan, et al.
(författare)
-
Erlang Capacity of UMTS Using Perceptual-based Power Control : An Analytical Framework
- 2009
-
Konferensbidrag (refereegranskat)abstract
- An analytical framework for calculation of Erlang capacity per cell of UMTS with perceptual-based power control is derived. A comparison of the capacity of the system using the proposed power control algorithm with its conventional counterpart is performed. This is supported by numerical results on Erlang capacity over a variety of system parameters for both considered power control approaches. It is shown that the use of perceptual speech quality metrics in power control results in a capacity gain of at least 10% over that of conventional UMTS.
|
|
