hash stringlengths 32 32 | doc_id stringlengths 5 12 | section stringlengths 5 1.47k | content stringlengths 0 6.67M |
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5692480e365e21a881d790cc4eaea394 | 45.912 | 11.7.6 Simulation results | Simulations are done for two types coding schemes (MCS-2-like and MCS-6-like) for TU3iFH and TU 50iFH channels for low band (GSM 900) and upper band (GSM 1800). Every type has three specific coding schemes: the standard MCS schemes, the RTTI type coding schemes assumed to have a 20-bit FANR bitmap, and the NBRTTI codin... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 11.7 Impacts to the Mobile Station | From the point of view of the transmitter, implementation aspects may be simplified by the usage of the 157/156/156/156 transmission option, as referenced in subclause 5.7 of 3GPP TS 45.010 (see note), as this would remove the complication introduced by the 0.25 bit.
NOTE. "Optionally, the BTS may use a timeslot length... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 11.8 Impacts to the BSS | From the point of view of transmission and reception, the impact is the same as in subclause 11.6.
Further, the BSS has to be able to handle received timeslots in a joint manner. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 11.9 Impacts to the Core Network | The core network impact is minimal, e.g. indication of feature support. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 11.10 Impacts to the Specification | A preliminary assessment of impacted specification follows. A more complete assessment can be done depending on whether the full set, or a subset, of components is pursued.
Table 212: Impacted 3GPP specifications
Specification
Description
3GPP TS 43.064
Overall description of the GPRS radio interface
3GPP TS 45.001
Phy... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 11.11 References | [1] T. S. Rappaport: "Wireless Communications: Principles and Practice", Second Edition, Prentice Hall PTR, 2002.
[2] 3GPP Organizational Partners: "Radio transmission and reception", TS 05.05 V8.10.0, 2001/06.
[3] R. Raheli, A. Polydoros and C. Tzou, "Per-survivor processing: a general approach to MLSE in uncertain en... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12 Adaptation between mobile station receiver diversity and dual-carrier | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.1 Introduction | Within the context of the GERAN Physical Layer evolution, where one of the prime targets is a smooth evolutionary path, two proposed candidates are receive diversity (see clause 6), and dual/multi-carrier (see clause 7).
This Subclause deals with a proposed technique, referred to as Capabilities Switching, which is app... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.2 Concept description | The underlying assumption of the proposal outlined in this subclause is that, if and when Receive Diversity (RxDiv) and Multi-carrier GERAN (MC) are introduced in the specification, it makes sense to allow the existence of a class of mobiles operating with the following two constraints.
a) RxDiv performances are requir... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.3 Performance Characterization | The performance of Capability Switching is the combination of the respective performances of Receive Diversity (see clause 6) and Dual/Multi-carrier (see clause 7). The combination depends on how the adaptation between the two modes is performed. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.4 Impacts to the Mobile Station | The MS will have to support switching commands between the two modes, and will have to indicate the switching capability. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.5 Impacts to the BSS | The BSS may have to add the switching option to its RRM algorithms. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.6 Impacts to the Core Network | The CN will have support the signalling of the switching capability support. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 12.7 Impacts to the Specification | The impact to specification is considered to be minimal, and depending on the specification impact of Receive Diversity and Dual/Multi-carrier. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13 Enhancements to resource allocation | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.1 Introduction | There are a number of allocation schemes defined for GPRS, including fixed allocation, Dynamic Allocation (DA) and Extended Dynamic Allocation (EDA). Of these EDA is the most capable since it permits the network to vary the weighting between transmit/receive slots from maximum downlink weighting to maximum uplink weigh... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.1.1 Benefits of the Solution | The proposed improvement will increase the statistical multiplexing efficiency of resource allocation on both the uplink and downlink during bursty packet data flows. It therefore constitutes a potential improvement to the 3GPP GPRS standards, enabling more efficient use of spectrum resources.
The benefit is likely to ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.1.2 Details of Allocation Rule | For B2DA a new rule of allocation and USF monitoring is proposed as follows which is illustrated below:
"The mobile station shall monitor the lowest numbered assigned PDCH. If the mobile station detects an assigned USF value for an assigned PDCH on the lowest numbered PDCH, the mobile station shall transmit RLC/MAC blo... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.2 USF and Timeslot Resources | A combination of USF and timeslot can be considered as a resource. There are 7 USF values for allocation to each mobile station on each timeslot, hence there are 56 USF-TS resources available for sharing across various mobile stations. Both Dynamic Allocation and Extended Dynamic Allocation schemes use N USF-TS resour... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.2.1 Co-existence with existing allocation schemes | In order that uplink resources can be allocated using dynamic allocation via the USF, two conditions must apply:
- the uplink resources are not also used by another mobile (since only one mobile can transmit on a given slot);
- the downlink slot on which the USF requires to be transmitted, in order to allocate the desi... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.3 Modelling Assumptions and Requirements | The proposal is likely to be beneficial when a number of users are employing data oriented services based on GPRS.
In order to quantify the benefits of the proposal the following modelling assumptions require to be specified:
- Modelling assumptions of traffic activity factors for uplink data services over GPRS. Note t... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.3.1 Illustration | In the following four scenarios are provided to show the potential use and advantages of B2DA. The following is assumed in all cases.
- 6 slots are available for 2 mobiles.
- Both are sending variable rate encoded video data at 15 frames per sec (60 ms rate) with a video frame timing offset of 20 ms.
- Assume that the... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.4 Performance Characterization | Since a video stream is isochronous there is a "hard" deadline for every video frame by which time it must have been transmitted; any later and it becomes a missing frame in the video output. According to [2] the number of erased frames must be limited to at most 2 %, but the delay is also a key component of the QoS. I... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.4.1 Cumulative Probability Distribution- MCS-1, QCIF 30 FPS | In order to quantify this benefit the cumulative probability distribution function of the transmit buffer length of MS2 for 10 hours of MPEG4 is shown below in figure 401. The CDF in this figure shows the probability that transmit buffer length is less than given number of RLC blocks. This indicates that when only EDA ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.4.2 Cumulative Probability Distribution- MCS-5, CIF 15 FPS | In order to illustrate that the benefits apply to more than one coding scheme and configuration, analogous results are shown in figure 404 for a situation where two mobiles transmit CIF at 15 frames per second using MCS-5. Performance advantage is greater than 50 %.
Figure 404: CDF of transmission buffer length for MS2... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.4.3 Summary of Performance Characterization | Using EDA alone, it would not be possible to share uplink resources between more than one mobile when transmitting variable rate delay sensitive real time streaming data such as MPEG4 video and expect both mobiles to receive a satisfactory QoS. For example, if each mobile individually needed 4 uplink slots, then the re... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5 Discussion: Improvement of B2DA | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5.1 Introduction | In order to enhance the resource allocation in GERAN Evolution, a new dynamic allocation scheme, Back to Back Dynamic Allocation, is presented above. B2DA can grow assigned uplink timeslots "forwards" and reduce the mutual blocking when sharing resources between different mobiles during burst packet data flows.
As ment... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5.2 Details of proposed allocation scheme | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5.2.1 New allocation rule based on B2DA | The main idea is that, the network could reduce the number of USF values allocated to a mobile station, each different assigned USF value would represent a different allocation and one of these assigned USF values should indicate an allocation of all assigned uplink PDCHs. Due to the reduction of USF values, an adjusti... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5.2.1 USF resource | The amount of USF values remaining unused on the lowest numbered assigned PDCH will influence the potential applicability of B2DA. However, it is possible to reduce the amount of USF values needed. The network can determine the amount of USF values needed in this allocation and establish the mapping of USF onto assigne... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.5.3 Benefits of the Solution | The improvement reduces the amount of USF values needed on the lowest numbered assigned PDCH. This will increase the statistical multiplexing efficiency of resource allocation when a number of mobile stations simultaneously require for dynamically allocated uplink resources. This allocation can also co-exist with exten... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 13.6 References | [1] Tdoc GP-052299: 3GPP TR 45.912 (V0.2.0): "Feasibility study for evolved GSM/EDGE Radio Access Network".
[2] 3GPP TS 22.105 (V6.3.0 - 2005-03): "Service Aspects: Services and Service Capabilities". |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14 Modified MBMS Service | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.1 Introduction | Release 6 adds new components to the GSM/EDGE air interface in support of Multicast Broadcast Multimedia Subsystem (MBMS) operation, including MBMS-specific re-transmission protocols and enhanced outer coding techniques. Although new and efficient competitive technologies are becoming available for multimedia service d... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.2 Concept description | Contemporary network designs for the delivery of spectrally efficient broadcast services - such as DVB-H and MediaFLO, and even hybrid systems such as 3GPP2 BCMCS simulcast transmissions from individual cells in single-frequency network (SFN) fashion where the participating cells support sufficiently precise time- and ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.3 Modelling Assumptions and Requirements | To evaluate the performance of single frequency network operation, the concatenated multipath channel experienced by the receiver must be characterised and then performance compared with unicast transmission. The following subclauses deal with modelling both methods of transmission in the same network for fair comparis... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.3.1 Channel Modelling | The Root Mean Square (RMS) delay spread measure provides a crude means of assessing the amount of time dispersion in the resulting SFN. In order to assess the effect of the SFN operation on RMS delay spread, System Configuration 2 defined in the GERAN SAIC Feasibility Study ([2], Clause 4) was used as the basis for ass... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.3.2 Broadcast Network C/I and C/N Distributions | At the outset of the original GERAN MBMS work [3] the channel to interference plus noise ratios (CINR) characterising GERAN networks in a variety of re-use patterns were studied. The CINR distributions for the centre site (all sectors) of System Configuration 2 of [2] assuming an MS noise-equivalent bandwidth of 200kHz... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.4 Receiver Link Performance | Table 217 lists and values required for operation at 10% radio link control (RLC) block error rate (BLER) under the SFN mode and re-use mode defined above for the example MIP's defined in figures 407 and 413 respectively. The specified values were derived from single-port receiver link simulations, but obviously dual... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.5 Radio Resource Management | A number of options could be available for providing radio resources to support a GSM SFN broadcast mode.
In the simplest approach, one or more non-hopping radio frequency channels could be dedicated on a network-wide basis or over a local set of cells to support the SFN, with a common training sequence code (TSC) app... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.6 Impacts to the Mobile Station | If the existing PDTCH MCS are retained for use in a GSM SFN broadcast channel mode, there would appear to be marginal impact to the MS RF subsystem specification, with the exception of the ability of the equalizer to deal with SFN-induced delay spread. However, as discussed in subclause 6.4, for contemporary medium- to... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.7 Impacts to the BSS | If the existing PDTCH MCS are retained for use in a GSM SFN broadcast channel mode, there would appear to be marginal impact on the BTS hardware, with the exception of the frequency hopping case. Existing transmitter designs capable of supporting error vector magnitudes consistent with MCS-9 transmission can clearly su... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.8 Impacts to the Core Network | Modified MBMS is seen as a feature that will enhance the performance of synchronous networks. It is not suitable for use in asynchronous networks. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.9 Impacts to the Specification | The specifications listed in table 218 will be impacted by Modified MBMS.
Table 218: Impacted 3GPP Specifications
Specification
Description
3GPP TS 43.246
Multimedia Broadcast/Multicast Service (MBMS) in the GERAN; Stage2
3GPP TS 44.060
General Packet Radio Service (GPRS); Mobile Station (MS) - Base Station System (BSS... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.10 Open Issues | Though RLC persistent mode in MBMS may be supported through unicast transmission using a separate resource, its impact on spectral efficiency has yet to be determined. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 14.11 References | [1] Y. Sun, R. Love, K. Stewart, K. Baum, B. Classon, V. Nangia, P. Sartori, "Cellular SFN broadcast network modelling and performance analysis", IEEE Vehic. Tech. Conf., Sept. 2005, pp. 2684‑2690.
[2] 3GPP TR 45.903: "Feasibility Study on Single Antenna Interference Cancellation (SAIC) for GSM networks".
[3] 3GPP TR 2... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15 Uplink throughput enhancements with low standard impact | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1 MS multislot capability switching | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.1 Introduction | For the downlink, two enhancements have been agreed as part of GERAN Evolution: Downlink dual carrier (see clause 7) doubles the peak data rate, and MSRD (see clause 6) increases both spectrum efficiency and data rate, the latter in particular at the cell edge. For balance between downlink and uplink, it would be desir... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.2 Timeslot allocation | For type 1 MS which cannot transmit and receive at the same time, 6 uplink timeslots are a realistic limit if one timeslot is needed for the downlink, e.g. to transmit ACK/NACK messages. The following examples are based on a downlink dual carrier MS since MS supporting more than 4 Tx slots can be expected to support do... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.3 Full-duplex MS | When either the receiver or the transmitter is inactive, the duplex filter can be bypassed. However, during simultaneous reception and transmission, the duplex filter causes considerable insertion loss in both directions.
In the downlink, the duplex filter insertion loss and the Tx noise in the Rx band will lower the s... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.4 Tx power | From Rel-5 onwards, the MS sends multislot power profiles to the network which indicate for each modulation separately the need for lower output power under multislot uplink operation.
With regard to average current drawn from the battery and radiated power, a multislot power reduction will probably continue to be need... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.5 Data rate increase | Under interference limited conditions where Tx power is not limiting the throughput, the throughput will scale with the number of uplink timeslots. If an MS supporting 6 uplink slots is compared with an MS supporting 4 uplink slots, the link-level throughput increase is 50 %.
In many cases, the link-level throughput ga... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.6 Data rate increase at the cell edge | In this subclause, the throughput curves of [1] and the assumption of an Rx level of -109 dBm at the cell edge [1] are used.
The MS is assumed to support 6 uplink slots 8-PSK without output power reduction. This MS is compared with a reference MS that supports 4 uplink slots with 6 dB power reduction as in [1]. The MS'... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.7 Impacts on mobile stations | The MS needs to have one or more temperature sensors to detect if overheating is imminent. However, a temperature sensor in the RF part is already state of the art.
Under normal conditions - 25 °C and 50 load at the antenna port - handsets can be designed to support up to six 8-PSK modulated Tx slots at 27 dBm withou... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.7.1 Full-duplex MS | Full-duplex MS will need a duplex filter with bypasses for Rx and Tx direction, and Rx and Tx synthesisers will have to run at the same time. (For the GSM-R band, a duplex filter may be not feasible.)
The I/Q interface between the baseband and the transceiver chip needs to support simultaneous reception and transmissio... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.8 Impacts on the BSS | New multislot classes need to be implemented. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.9 Impacts on the core network | No impacts expected. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.10 Impacts on the specification | Since the standard already allows:
- different output power reductions for GMSK and 8-PSK from Rel-5 onwards;
- the possibility to reduce the multislot or power class if really needed; and
- full-duplex MS;
- only a few amendments are necessary;
- definition of new multislot classes: 3GPP TS 45.002;
- Rx performance re... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.1.11 Summary | In order to increase the uplink throughput, it is proposed that half-duplex MS use up to 6 uplink timeslots and that full-duplex MS use up to 8 uplink timeslots. Half-duplex EGPRS handsets with RLC/MAC uplink data rates of up to 355 kbit/s and full-duplex EGPRS handsets with RLC/MAC uplink data rates of up to 473 kbit/... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2 Type 2 MS Implementation | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.1 Concept Description | Full duplex operation is defined as the simultaneous transmission and reception of a signal. This technique requires a duplex filter in order to isolate receive and transmit paths.
Small ceramic, SAW, Film Bulk Acoustic Resonator (FBAR), and Bulk Acoustic Wave (BAW) based duplexers are available today and exhibit reaso... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.2 Void | 15.2.2a Interference Frequencies
15.2.2a.1 Introduction and Purpose
One of the types of interference in the receive band of a type 2 GSM mobile results from non-linear components in the receiver (such as the LNA and the mixer) combining the attenuated signal from the transmitter with other unwanted signals. These unw... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.3 Void | 15.2.3a Transmitter Output Power Levels
Three cases for the transmitter output power levels are considered.
15.2.3a.1 No Maximum Output Power Reduction
The first case illustrates the situation where the type 2 mobile is expected to meet the maximum output power requirements as specified for the mobile class in [8].... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.4 Void | 15.2.4a Analysis Assumptions
The interference and blocking signal frequencies and power levels are discussed in Section 15.2.2a.
Sensitivity requirements depend on the logical channel, the expected error rate, and the propagation environment. For AMR12.2 with FER 1%, the required SNR can easily vary between 8 dB and ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.5 Duplexer and Receive Filter Requirements | |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.5.1 Introduction | This section discusses the filter parameters that are used in the various analyses for different type 2 mobile architectures. Specifications that are used in these analyses are given. As type 2 GSM mobiles are not currently manufactured, some of the filters required are not available. Filter specifications for some... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.5.4 Duplexer Filter Specifications | The EPCOS B7638 duplexer was available for the GSM 850 band and is used in this analysis. For the PCS band, the EPCOS BAW B7633 duplex filter for CDMA applications was used in this analysis. Duplex filters were not found for the EGSM and DCS bands, so the filter specifications for these bands were derived from the ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.5.7.1 Concept Description | The receive/transmit band is divided into two equal sub-bands. Each duplexer will then have a passband which is only half as wide, and a guard band which is increased by half the passband width. Therefore it can be implemented with a relatively simple filter design which will have very much reduced insertion loss. Extr... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.5.7.3 Impacts on the Analysis | Determination of the estimated filter parameters using this duplexer arrangement, and the subsequent analysis of the various architectures, is TBD. |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.6 Void | 15.2.6a Basic Type 2 Architecture
15.2.6a.1 Introduction
This section discusses interference in the receive band of a type 2 mobile resulting from non-linearity in the receiver coupled with the presence of a transmit signal. Three different options for basic type 2 receiver architecture are discussed and analyzed. U... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.7 Void | 15.2.7a Modified Type 2 Architecture
15.2.7a.1 Introduction
This section discusses interference in the receive band of a GSM850 and EGSM900 type 2 mobile resulting from non-linearity in the receiver coupled with the presence of a transmit signal. In section 15.2.6a, a basic receiver architecture that used a duplexer ... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.8 Void | 15.2.8a Hybrid Type 2 Architecture
15.2.8a.1 Introduction
This section discusses interference in the receive band of a type 2 mobile resulting from non-linearity in the receiver coupled with the presence of a transmit signal. A hybrid architecture is discussed, which allows the mobile to operate as a type 2 mobile, bu... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.2.9 Areas for Further Study | There are several areas that need further study for this implementation. To name a few:
- It needs to be evaluated whether the attenuation in the paired frequency bands that is offered by the duplex filters is enough to meet spectral and interference requirements for GSM.
- The impact of the duplex filter return loss (... |
5692480e365e21a881d790cc4eaea394 | 45.912 | 15.3 References | [1] AHGEV-060035, Modified Dual Symbol Rate Concept for Future GERAN Evolution, AdHoc on GERAN Evolution, May 2006
[2] AHGEV-060016: "Discussion on Uplink Coverage," AdHoc on GERAN Evolution, May 2006
[3] NP-010125, 3GPP TSG CN Plenary #11, Palm Springs, U.S.A, 14th - 16th March 2001
[4] void
[5] void
[6] EPCOS Prelimi... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 1 Scope
| The present document gives background information on the performance of the GSM half rate speech codec. Experimental results from the characterization and verification tests carried out during the selection process by the Traffic CHannel Half rate Speech (TCH-HS) expert group are reported to give a more detailed pictur... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 2 References
| The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or non‑specific.
• For a specific reference, subsequent revisions do not a... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 3 Abbreviations
| For the purposes of the present document, the following abbreviations apply:
A/D Analogue to Digital
ACR Absolute Category Rating
ANOVA ANalysis Of VAriance
C/I Carrier-to-Interferer ratio
CEPT Conférence Européenne des Postes et Télécommunications
CNI Comfort Noise Insertion
D/A Digital to Analogue
DAT Digital... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 4 Quality under error conditions (A-law, IRS), Experiment 1
| A listening-only test was chosen, adopting the Absolute Category Rating (ACR) method.
Subjective tests were carried out by BT (United Kingdom), CSELT (Italy), and Deutsche Telekom (Germany). Table 1 reports the results obtained in Experiment 1: each cell shows the difference in terms of equivalent Q values between the... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 5 Quality under error conditions (UPCM, No IRS), Experiment 2
| A listening-only test was chosen, adopting the Absolute Category Rating (ACR) method.
Subjective tests were carried out by BT (United Kingdom), CSELT (Italy), and DEUTSCHE TELEKOM (Germany). Table 2 reports the results obtained in Experiment 2: each cell shows the difference in terms of equivalent Q values between the... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 6 Quality under tandeming conditions
| |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 6.1 Quality under tandeming conditions, Experiment 3
| A listening-only test was chosen, adopting the Absolute Category Rating (ACR) method. Subjective tests were carried out by BT (United Kingdom), CSELT (Italy), and DEUTSCHE TELEKOM (Germany). Table 3 reports the results obtained in Experiment 3: each cell shows the difference in terms of equivalent Q values between the ... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 6.2 Effect of tandeming with other standards, Experiment 7
| The experiment was conducted in two different laboratories: BT (UK) and CNET (France).
The following standards were tandemed with the half rate codec in this experiment: half rate, full rate, ITU-T Recommendation G.726 [2] (at 32 kbit/s) and G.728 [3]. Both possible orders of tandeming were tested for each of these ca... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 7 Quality under background noise conditions
| |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 7.1 Experiments 4 and 5
| International subjective test programs have been conducted in the past, by both the ITU and ETSI, to investigate the effects of environmental noise. This has proved to be a difficult area to evaluate, and more satisfactory methodologies are continually being sought to improve the accuracy of these tests. Several method... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 7.2 Special background noise
| |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 7.2.1 Introduction
| Some informal listening sessions were carried out to further investigate background noise effects. Speech samples from four different talkers were electronically mixed (at 3 different Signal-to-Noise Ratios; 5 dB, 10 dB, and 20 dB) with a wide range of different background noises, reflecting the following types of envi... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 7.2.2 Observations
| At the lower Signal-to-Noise Ratios, the speech was often unintelligible without considerable concentration and effort on the part of the listener. In some cases, even where the listener was familiar with the speech material, it was impossible to understand some parts of the speech.
The codec had the effect of making ... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 8 Assessment of equivalent qdu, Experiment 6
| The experiment on the assessment of qdu was designed to assess the half rate codec performance, in error free conditions, in terms of Equivalent Quantization Distortion Units (qdu) as defined by the ITU-T. Two laboratories performed the experiment (CSELT and DEUTSCHE TELEKOM) and the following conclusions were drawn fr... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 9 Talker dependency, Experiment 8
| From the results obtained in the two laboratories which conducted this experiment, the performance of any given condition undoubtedly varies from talker to talker.
The existence of this talker dependency has been confirmed by a further analysis applied to the results from the first phase of characterization testing.
... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10 DTX System
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fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.1 Assessment of DTX algorithm, Experiment 9
| The four laboratories who performed the subjective evaluation of DTX functions concentrated their expert listening on the following effects, using conversational speech;
- Voice Activity Detection (VAD); and
- Comfort Noise Insertion (CNI).
For this, the speech material available was monitored for the following effe... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2 Channel activity in DTX mode
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fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.1 Test procedure
| Speech material recorded during testing of the full rate DTX system was processed through the codec/DTX hardware. This material comprised real conversations in the English, French, German and Italian languages. The activity of the VAD algorithm was measured for all 480 conversations. The mean channel activity was then ... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.2 Speech channel activity
| The percentage of speech frames scheduled for transmission by the radio sub-system (subsequently referred to as the speech channel activity) varied significantly between conversations. Speech channel activities ranged from 35 % to 85 % for individual sides of a conversation. For this reason, it was not possible to iden... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.3 Level compensation
| During the expert listening, it was found that the speech material had been processed at a level 6,5 dB below the original recorded level. However, the activity of the basic VAD algorithm rises approximately 0,5 % per dB increase in input level. To compensate for this, a factor of 3 % must be added to the speech channe... |
fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.4 SID update rate
| The DTX handler simulation used a SID update period of 480 ms. The SID update rate has subsequently been reduced to 240 ms. This modification will raise the speech channel activity by approximately 2 %.
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fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.5 Interleaving compensation
| The channel measurements were calculated on a signal frame basis. However, the use of interleaving (depth 4) implies that the TDMA activity will be approximately 2 % higher than the signal frame activity.
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fc902c14a58d85cbc46880929a1ebce4 | 46.008 | 10.2.6 Estimated mean TDMA channel activity
| The estimated mean TDMA channel activity is shown in table 6.
Table 6: Calculation of mean TDMA channel activity
speech channel activity
55 %
level compensation
3 %
240 ms SID update period
2 %
interleaving compensation
2 %
total TDMA channel activity
62 %
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