1 Scope
3GPP43.050Release 17Transmission planning aspects of the speech service in the GSM Public Land Mobile Network (PLMN) systemTS
The present document describes the transmission planning aspects pertaining to the speech service in the GSM PLMN system. Due to technical and economic factors, there cannot be full compliance with the general characteristics of international telephone connections and circuits recommended by the ITU‑T.
The present document gives guidance as to the precautions, measures and minimum requirements needed for successful interworking of the PLMN with the national and international PSTN. The present document identifies a number of routeing and network configurations. The objective is to reach a quality as close as possible to ITU‑T standards in order to safeguard the performance seen by PSTN customers.
The requirements stated for acoustics in dual mode GSM/3GPP handsets shall be interpreted as requirement on acoustics in the GSM mode.
1.1 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 apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1] 3GPP TR 41.004: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms".
[2] 3GPP TS 43.004: "Digital cellular telecommunications system (Phase 2+); Signalling requirements relating to routeing of calls to mobile subscribers".
[3] 3GPP TS 46.001: "Digital cellular telecommunications system (Phase 2+); Full rate speech processing functions".
[4] 3GPP TS 46.010: "Digital cellular telecommunications system (Phase 2+); Full rate speech; Transcoding".
[5] 3GPP TS 46.011: "Digital cellular telecommunications system (Phase 2+); Full rate speech; Substitution and muting of lost frames for full rate speech channels".
[6] 3GPP TS 46.012: "Digital cellular telecommunications system (Phase 2+); Full rate speech; Comfort noise aspect for full rate speech traffic channels".
[7] 3GPP TS 46.031: "Digital cellular telecommunications system (Phase 2+); Full rate speech; Discontinuous Transmission (DTX) for full rate speech traffic channels".
[8] 3GPP TS 46.032: "Digital cellular telecommunications system (Phase 2+); Voice Activity Detection (VAD)".
[9] 3GPP TS 46.002: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech processing functions".
[10] 3GPP TS 46.020: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Half rate speech transcoding".
[11] 3GPP TS 46.021: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Substitution and muting of lost frames for half rate speech traffic channels".
[12] 3GPP TS 46.022: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Comfort noise aspects for half rate speech traffic channels".
[13] 3GPP TS 46.041: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels".
[14] 3GPP TS 46.042: "Digital cellular telecommunications system (Phase 2+); Half rate speech; Voice Activity Detection (VAD) for half rate speech traffic channels".
[15] I‑ETS 300 245‑2: "Integrated Services Digital Network (ISDN): Technical characteristics of telephony terminals: Part 2: PCM A‑Law handset telephony".
[16] ITU‑T Recommendation G.103 (1998): "Hypothetical reference connections".
[17] ITU‑T Recommendation G.111 (1993): "Loudness ratings (LRs) in an international connection".
[18] ITU‑T Recommendation G.113 (1996): "Transmission impairments".
[19] ITU‑T Recommendation G.114 (2000): "Mean one‑way propagation time".
[20] ITU‑T Recommendation G.121 (1993): "Loudness ratings (LRs) of national systems".
[21] ITU‑T Recommendation G.122 (1993): "Influence of national systems on stability, talker echo, and listener echo in international connections".
[22] ITU‑T Recommendation G.131 (1996): "Control of talker echo".
[23] ITU‑T Recommendation G.168 (2000): "Digital network echo cancellers".
[24] ITU‑T Recommendation G.223 (1988): "Assumptions for the calculation of noise on hypothetical reference circuits for telephony".
[25] ITU‑T Recommendation G.703 (1998): "Physical/electrical characteristics of hierarchical digital interfaces".
[26] ITU‑T Recommendation G.711 (1988): "Pulse code modulation (PCM) of voice frequencies".
[27] ITU‑T Recommendation G.712 (1996): "Transmission performance characteristics of pulse code modulation".
[28] ITU‑T Recommendation G.167 (1993): "Acoustic Echo Controllers".
[29] ITU‑T Recommendation M.1020 (1993): "Characteristics of special quality international leased circuits with special bandwidth conditions".
[30] ITU‑T Recommendation M.1025 (1993): "Characteristics of special quality international leased circuits with basic bandwidth conditioning".
[31] ITU‑T Recommendation M.1030 (1988): "Characteristics of ordinary quality international leased circuits forming part of private switched telephone networks".
[32] ITU‑T Recommendations M.1040 (1988): "Characteristics of ordinary quality international leased circuits".
[33] ITU‑T Recommendation O.132 (1988): "Specification for a quantizing distortion measuring apparatus using a sinusoidal test signal".
[34] ITU‑T Recommendation P.11 (1993): "Effect of transmission impairments".
[35] ITU‑T Recommendation P.340(2000): "Transmission characteristics of hands‑free telephones".
[36] ITU‑T Recommendation P.38 (1993): "Transmission characteristics of operator telephone systems (OTS)".
[37] ITU‑T Recommendation P.50 (1999): "Artificial voices".
[38] ITU‑T Recommendation P.51 (1996): "Artificial mouths".
[39] ITU‑T Recommendation P.64 (1999): "Determination of sensitivity/frequency characteristics of local telephone systems".
[40] ITU‑T Recommendation P.76 (1988): "Determination of loudness ratings; fundamental principles".
[41] ITU‑T Recommendation P.79 (1999): "Calculation of loudness ratings".
[42] ITU‑T Recommendation Q.35/E180 (1998): "Technical characteristics of tones for the telephone service".
[43] ITU‑T Recommendation Q.551 (1996): "Transmission characteristics of digital exchanges".
[44] ITU‑T Blue Book (1988): "Volume V, Supplement 13: Noise spectra".
[45] ISO 3 (1973): "Preferred numbers – series of preferred numbers".
[46] ITU‑T Recommendation P.57 (1996): "Artificial Ears".
[47] ITU‑T Recommendation P.58 (1996): "Head and Torso Simulator for Telephonometry".
[48] I‑ETS 300 245‑3: "Integrated Services Digital Network (ISDN): Technical characteristics of telephony terminal: Part 3: PCM A‑law loudspeaking and handsfree telephony".
[49] 3GPP TS 26.131: “Terminal Acoustic Characteristics for Telephony; Requirements”
[50] 3GPP TS 26.132: “Speech and video telephony terminal acoustic test specification”
[51] 3GPP TS 51.010: "Digital cellular telecommunications system (Phase 2+); Mobile Station (MS) conformance specification"
1.2 Abbreviations
In addition to those below, the abbreviations used in the present document are listed in GSM 01.04.
ADC Analogue to Digital Converter
ADPCM Adaptive Differential Pulse Code Modulation
AEC Acoustic Echo Control
BSC Base Station Controller (excluding transmission systems
BTS Base Transceiver Station (excluding transmission systems)
DAC Digital to Analogue Converter
DMR Digital Mobile Radio
DSI Digital Speech Interpolation
EEC Electric Echo Control
EL Echo Loss
ERP Ear Reference Point
FDM Frequency Division Multiplex
ISC International Switching
LE Local Exchange
LSTR Listener Sidetone Rating
MRP Mouth Reference Point
OLR Overall Loudness Rating
PCM Pulse Code Modulation
POI Point of Interconnection (with PSTN)
RLR Receiver Loudness Rating
SLR Send Loudness Rating
STMR Sidetone Masking Rating
UPCMI 13‑bit Uniform PCM Interface
1.3 Introduction
Since the transmission quality and the conversational quality of the PLMN will in general be lower than the quality of the PSTN connection due to coding distortion, delay, etc., only some transmission aspects can be brought in line with ITU‑T Recommendations. It is therefore necessary to improve the overall quality as much as possible by implementing proper routeing and network configurations.
It should be recognized that the transmission plan for the GSM PLMN cannot lead to major changes in the PSTN. However, it is important to use the improvements in the evolving PSTN (e.g. digitalization, introduction of echo cancellers) in an effective way.
The transmission requirements are in the first place based on international connections. When the quality is sufficient for international connections, it can be assumed that the national connections will have the same or better quality.
In order to obtain a sufficient quality in the connection, it is preferable to have digital connectivity between the Base Station System (BSS) and the international exchange. The PLMN requirements are based on this assumption. When this situation cannot be provided, a lower quality must temporarily be accepted.
The present document consists of two parts: one will deal with network configurations, the other with transmission performance.
The part about network configurations gives information about the reference connections, on which the transmission plan is based. Furthermore, some guidelines are presented for improvement of the transmission quality in the evolving (digital) PSTN.
The part about transmission performance gives mainly characteristics of the transmission between MS acoustic interface (MRP/ERP) and the interface between the PLMN and the PSTN (POI). For transmission aspects where it is impossible to give overall characteristics, it is in some cases necessary to make recommendations for individual parts of the equipment.
Annex A considers the effects of the type of acoustic interfaces of the MS.