1、 Recommendation ITU-R SM.2093-0 (08/2016) Methods for measurements of indoor radio environment SM Series Spectrum management ii Rec. ITU-R SM.2093-0 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum b
2、y all radiocommunication 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 Confe
3、rences and Radiocommunication 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 a
4、nd licensing declarations 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 availabl
5、e online at http:/www.itu.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 ser
6、vices P Radiowave propagation 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 f
7、requency standards emissions 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, 2016 ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means wha
8、tsoever, without written permission of ITU. Rec. ITU-R SM.2093-0 3 RECOMMENDATION ITU-R SM.2093-0 Methods for measurements of indoor radio environment (2016) Scope For indoor radio environment measurements, there is a need to have a uniform, frequency-independent method to produce comparable, accura
9、te and reproducible results between different measurement systems. This Recommendation provides a set of processes or steps that need to be integrated in a measurement procedure resulting in these comparable results. Keywords Indoor radio environment measurements, noise measurements Abbreviations AC
10、F Amplitude correction factor AGC Automatic gain control APD Amplitude probability distribution CISPR Comit International Spcial Des Perturbations Radiolectriques DFT Discrete Fourier Transformation FIR Finite impulse response IEC International Electrotechnical Commission IN Impulsive noise I/Q In-p
11、hase/Qadrature LAN Local area network LNA Low noise amplifier PC Personal computer PLT Power line telecommunication RBW Resolution bandwidth RFID Radio Frequency IDentifier RMS Root mean square SCN Single carrier noise UWB Ultra-wide band VSWR Voltage standing wave ratio WGN White Gaussian noise Rel
12、ated ITU Recommendations, Reports Recommendation ITU-R P.372 Recommendation ITU-R SM.1753 Report ITU-R SM.2055 Report ITU-R SM.2155 Report ITU-R SM.2157 NOTE In every case the latest edition of the Recommendation/Report in force should be used. 4 Rec. ITU-R SM.2093-0 The ITU Radiocommunication Assem
13、bly, considering a) that, due to the introduction of many types of electrical and electronic equipment (emitting unintentional radio waves), and communication networks (e.g. ultra-wide band (UWB), power line telecommunication (PLT) and computers), the radio environment including interference for ind
14、oor applications might be getting worse; b) that, radio interference from single and identifiable sources being dominant in indoor environments does not fit the definition of man-made noise specified in Recommendation ITU-R P.372; c) that, for efficient spectrum management, administrations and/or ma
15、nufacturers of radio applications operating indoors need to know the radio environment including interferences; d) that there is a need to harmonize the measurement methods for indoor radio environment measurements to achieve reproducible results that can be mutually compared; e) that, for the indoo
16、r radio environment measurements, certain minimum equipment specifications and measurement methods are required that are different from the ones applied to outdoor radio noise measurements covered in Recommendation ITU-R SM.1753, recommends that measurements of indoor radio environment should be car
17、ried out as described in Annex 1. Annex 1 Methods for measuring indoor radio environment 1 Introduction This Annex describes methods for measuring and evaluating the indoor radio environment faced by radiocommunication applications. Considering the usage of radio devices in indoor locations, measure
18、ment of the radio environment in frequency ranges above 30 MHz may be required in practice. 2 Components of radio environment Major radio sources in indoor environment are emissions from electrical and electronic devices used inside the respective facility. Radio noises as described in Recommendatio
19、n ITU-R P.372 may get into a facility from the outdoor environment but its interfering effect is usually less than the emissions from indoor sources. Using the definition given in Recommendation ITU-R P.372, radio noise is the aggregate of emissions from multiple sources that do not originate from r
20、adiocommunication transmitters. If at a given measurement location there is no dominance of single noise sources, the characteristic of the radio noise often has a normal amplitude distribution and can be regarded as white Gaussian noise. However, with the high density of noise emitting devices espe
21、cially found in indoor environments, it is virtually impossible to find a location that is not at least temporarily dominated by emissions Rec. ITU-R SM.2093-0 5 from a single source. These sources often emit impulses and/or single carriers. Since radiocommunication equipment has to operate in such
22、an environment, it is necessary to include noise or emissions from nearby sources in measurements of the indoor radio environment. The following components of radio noise are defined in Recommendation ITU-R SM.1753. TABLE 1 Components of radio noise Noise component Properties Sources (examples) Whit
23、e Gaussian noise(1) (WGN) Uncorrelated electromagnetic vectors Bandwidth equal to or greater than receiver bandwidth Spectral power level increases linear with bandwidth Computers, power line communication networks, wired computer networks, cosmic noise Impulsive noise (IN) Correlated electromagneti
24、c vectors Bandwidth greater than receiver bandwidth Spectral power level rises with square of bandwidth Ignition sparks, lightning, gas lamp starters, computers, ultra-wideband devices Single carrier noise (SCN) One or more distinct spectral lines Bandwidth smaller than receiver bandwidth Spectral p
25、ower level independent of bandwidth Wired computer networks, computers, switched mode power supplies (1) In the context of this Recommendation, WGN is considered to represent a continuous noise signal which exhibits a nearly flat power spectral density in the frequency ranges around the measurement
26、bandwidth. Recommendation ITU-R SM.1753-2 also includes the following descriptions. While the WGN component is sufficiently characterized by the r.m.s. value, this is much more difficult for the IN. Modern digital communication services almost always apply error correction, making it more immune esp
27、ecially against impulsive noise. However, when certain pulse lengths and repetition ratios are reached, IN can significantly interfere with the operation of such a service. It is therefore desirable to measure radio noise in a way that gives not only the level of IN but also certain information abou
28、t the statistical distribution of pulse parameters. According to the description, characteristics of WGN and IN should be evaluated separately, since their mechanism of the impact on wireless communication system is different from each other. Single carrier noise (SCN) is only detected as such when
29、it comes from a single source near the measurement location. However, SCN is often a dominant component of the indoor radio environment where wireless systems must also work. Therefore the levels of all three components defined in Table 1 forming the indoor radio environment should be included in th
30、e measurement results. 6 Rec. ITU-R SM.2093-0 3 Key parameters of radio environment The measurement procedures described here will deliver the results for the following key parameters of radio environment: WGN: RMS level, presented as a single value. IN: Peak level, presented as a distribution; Impu
31、lse/burst duration, presented as a distribution; Impulse/burst period, presented as a distribution; Total impulse/burst time. SCN: RMS level of the highest interfering single carrier. The key parameters in indoor environment are presented as a distribution obtained from multiple point measurement de
32、scribed in section 4. The details of the evaluation procedures for the Key parameters are described in section 9. 4 Measurement principles Unlike outdoor environments, indoor radio environments depend considerably on the exact location of the measurement points, even within a room, because there is
33、a high density of radio noise sources in a room, and there are influences on propagation characteristics due to reflections on the walls, the ceiling or the presence of structures there. Therefore it is not adequate to determine radio environment characteristics by measurement at only a single point
34、 in a room. Acquiring the radio environment data at multiple points in a room or an installation is recommended. For multiple points measurement, a method that can measure SCN, WGN, and IN in a short time is necessary. The number of measurement points should be decided by considering the floor space
35、 of that location (e.g. 50 points per 100 m2). The method described in this Recommendation adopts post processing of I/Q data obtained by a vector signal analyser or a monitoring receiver. This measurement method is referred to as “I/Q data sampling method”. It can acquire SCN, WGN, and IN data at a
36、ny combination of resolution bandwidth and centre frequencies from I/Q data as long as they are inside the measured frequency band. Spectrograms, essential for SCN detection, can also be obtained from I/Q data. 5 Environmental categories The radio environment mainly depends on dominant interference
37、sources used in the building. Therefore, the environment categories for indoor measurement should be based on the usage of electrical and/or electric apparatuses, rather than the surrounding environment of the building as shown in Table 2. The table also shows the examples of locations for each cate
38、gory in order to help categorization of candidate locations. Rec. ITU-R SM.2093-0 7 TABLE 2 Selection criteria for indoor measurement locations and examples Category Definition Examples of locations Active time (hours) Domestic Single house or flat with typical electrical and electronic appliances f
39、or private use Residence, apartment-house, dormitory, guest room in hotel Evening times e.g. 17:00 21:00, but depends on peoples lifestyle (Electric devices should be activated for measurement) Office Electrical and electronic appliances for business use, IT and telecommunication equipment, e.g. com
40、puters, printers, local area networks Office work room, staff room Working time e.g. 9:00 12:00 and 13:00 17:00 Shopping centre Locations with shops and supermarkets Retail shop, restaurant, amusement area, reception area, indoor car park, museum, theatre, library Opening time; activity of devices m
41、ay depend on the number of customers. Railway station Major railway stations inside roofed platform area Inside roofed platform area including subways Depends on the traffic. e.g. 7:00 10:00, 17:00 20:00 Airport terminal Major airports, inside terminal building Check-in counter area, boarding area,
42、arrivals area Depends on the traffic e.g. 8:00 21:00 Factory Inside factory buildings dominated by electrical machinery Production factory, maintenance facility, warehouse Working time e.g. 9:00 12:00 and 13:00 17:00 Hospital Locations dominated by medical appliances Clinic, consultation room and tr
43、eatment room in hospital Working time e.g. 9:00 12:00 and 13:00 17:00 6 Equipment specifications 6.1 Receiver and preamplifier A vector signal analyser or a monitoring receiver which can produce I/Q data is required as a measurement receiver. An external low noise amplifier (LNA) can be used to impr
44、ove sensitivity. The following requirements should be applied to the combination of analyser/receiver and LNA. 8 Rec. ITU-R SM.2093-0 TABLE 3 Measurement system (receiver/LNA) requirements Function Requirement Frequency range 30-300 MHz 0.3-3 GHz Minimum acquisition bandwidth (I/Q sampling rate) 1 M
45、Hz 5 MHz Input (antenna input) VSWR 50 , nominal 90 dB 100 dB Image rejection 90 dB 100 dB LNA gain 25 dB 25 dB LNA gain stability 0.7 dB at 20-30C LNA gain flatness over the acquisition bandwidth 0.4 dB 0.5 dB Automatic gain control (AGC) Measurement outputs should have no AGC applied Electromagnet
46、ic compatibility of the measurement set-up including computers and interface All interference produced and received by the set-up should be less than 10 dB below the average noise to be measured.(2) (1) This noise figure applies to the LNA. (2) The measurement frequency should be shifted so as to sa
47、tisfy the requirement in the case that interferences are received in the measuring frequency band. When an LNA is used, the requirements in Table 2 have to be met by the whole combination of receiver and LNA. The system noise figure of the combination is dominated by the noise figure of the LNA. An
48、external attenuator may be used in order to assure input impedance of analyser/receiver or LNA. For improving sensitivity, an external attenuator may not to be used. 6.2 Antenna In indoor environments, usually dominant radio noise sources exist in the vicinity, and the arrival angle of the noise can
49、not be considered as uniform. Therefore, the use of directive antenna is inappropriate for measurements in these environments. The most appropriate antenna for all measurement frequency band is a vertical half-wave dipole because it has low loss which can be regarded as lossless and omni-directional gain in the horizontal Rec. ITU-R SM.2093-0 9 plane. A vertical ground plane antenna or sleeve antenna can also be used as they have similar characteristics to the half-wave dipole antenna. Below 300 MHz, vertical half-wave dipoles are not practical
