1、 Recommendation ITU-R V.665-3 (08/2015) Traffic intensity unit V Series Vocabulary and related subjects ii Rec. ITU-R V.665-3 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunicatio
2、n services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommuni
3、cation Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declaratio
4、ns by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.i
5、tu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propa
6、gation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emis
7、sions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2015 ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without writte
8、n permission of ITU. Rec. ITU-R V.665-3 1 RECOMMENDATION ITU-R V.665-3 Traffic intensity unit (1986-1990-2000-2015) Scope This Recommendation defines the variable “traffic intensity” and the unit used: the erlang (E). Keywords Traffic intensity, erlang Related ITU Recommendations Recommendation ITU-
9、R V.430-4 Use of the international system of units (SI) Recommendation ITU-R V.431-8 Nomenclature of the frequency and wavelength bands used in telecommunications Recommendation ITU-R V.573-6 Radiocommunication vocabulary Recommendation ITU-R V.574-5 Use of the decibel and the neper in telecommunica
10、tions The ITU Radiocommunication Assembly, considering a) that in ITU-T texts concerning telephone operations and tariffs and in ITU-R texts concerning radiotelephone transmissions (e.g. telephone radio-relay systems and the maritime mobile service radiotelephony), the quantity “traffic intensity” i
11、s used together with the unit in which it is expressed. With progress in telecommunications, increasing use will be made of this term and this unit; b) that the variable “traffic intensity” and its unit “erlang” are defined in Recommendation ITU-T E.600 and reproduced below, recommends 1 that for te
12、lecommunication purposes, the following definitions should be used: traffic intensity: The instantaneous traffic intensity in a pool of resources1 is the number of busy resources at a given instant of time. NOTE 1 Statistical moments may be calculated for a given period of time, for instance the mea
13、n traffic intensity ),( 21 ttA is related to the instantaneous traffic intensity A(t) as: 21d)(1),( 1221 ttttAttttA In applications, the term traffic intensity usually has this meaning of mean traffic intensity. NOTE 2 Traffic intensity is equivalent to the product of arrival rate and mean holding t
14、ime. 1 The term “resource” means any physically or conceptually identifiable entity, whose use and state at any time can be unambiguously determined, for example, a telecommunication circuit, a switching equipment, a subscriber line or a radio channel. 2 Rec. ITU-R V.665-3 NOTE 3 The unit usually us
15、ed for traffic intensity is the erlang (symbol: E). erlang: Unit of traffic intensity (symbol: E). 1 erlang is the traffic intensity in a pool of resources when just one of the resources is busy. NOTE The name “erlang” was given to the traffic unit in 1946 by the CCIF, in honour of the Danish mathematician, A. K. Erlang (1878-1929), who was the founder of traffic theory in telephony.
