1、 Recommendation ITU-R M.1825(10/2007)Guidance on technical parameters and methodologies for sharing studies related to systems in the land mobile serviceM SeriesMobile, radiodetermination amateurand related satellite servicesii Rec. ITU-R M.1825 Foreword The role of the Radiocommunication Sector is
2、to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by 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 functi
3、ons of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences 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 refere
4、nced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and 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 IT
5、U-R patent information database can also be found. Series of ITU-R Recommendations (Also available 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 ser
6、vice (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services 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 an
7、d fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency 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, 2
8、009 ITU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R M.1825 1 RECOMMENDATION ITU-R M.1825 Guidance on technical parameters and methodologies for sharing studies related to systems in the land mobile se
9、rvice (Question ITU-R 7/8) (2007) Scope This Recommendation gives guidance to perform sharing studies related to systems in the land mobile service. It establishes a list of parameters, that characterize a system to assist in sharing studies, provides information on the methodologies that can be use
10、d for sharing analyses involving the land mobile service and describes mitigation techniques that can improve spectrum sharing. It also contains a list of relevant ITU-R Recommendations, Reports and Handbooks. The ITU Radiocommunication Assembly, considering a) that the technical characteristics of
11、systems in the land mobile service can vary; b) that there is a potential for the introduction of new types of systems or services in the bands used by the land mobile service; c) that representative technical and operational characteristics of systems operating in bands allocated to the land mobile
12、 service are required to determine the feasibility of introducing new types of systems; d) that procedures and methodologies are needed to analyse compatibility between systems operating in the land mobile service and systems in other services, noting a) the list of relevant Recommendations, Reports
13、 and Handbooks listed in Annex 3, recommends 1 that the list of parameters in Annex 1 should be used as guidance on characteristics of systems in the land mobile service appropriate for use in sharing studies; 2 that the methodologies in Annex 2 should be used for sharing studies between systems in
14、the land mobile service (intra-service sharing) and between systems in the land mobile service and systems in other services (inter-service sharing). Annex 1 Technical parameters of land mobile systems for sharing studies 1 Introduction For any sharing study it is necessary to have the characteristi
15、cs of the systems that need to share the spectrum. Section 2 provides a list of parameters whose values should be able to characterize a system for the purpose of sharing studies. 2 Rec. ITU-R M.1825 2 General list of parameters It is desirable that the land mobile service characteristics in the tab
16、le below be used in sharing studies. However, it should be noted that not all the parameters below are relevant for each land mobile system and as such, may not be found in the associated standards. As a result, care should be taken in determining the relevant parameters and their values for sharing
17、 studies between specific systems. General Frequency band (MHz) Type of emission Deployment type (e.g. cellular ) Access technique Number of sectors Frequency reuse factor Antennas per sector Type of antenna systems Co-located antenna minimum coupling loss (dB) System Channel bandwidth (kHz) Modulat
18、ion type Duplex method Typical BER or SINAD or FER Transmitter Output power (W) ERP or EIRP (dBW or dBm) Necessary channel bandwidth (kHz) ACLR (adjacent channel leakage ratio) or out-of-band emission mask Antenna gain (dBd or dBi) Antenna height (m) Radiation pattern Antenna polarization Receiver N
19、oise figure (dB) IF filter bandwidth (kHz) Sensitivity (dBm) Off-channel-sensitivity: ACS (adjacent channel selectivity) Blocking characteristics (in-band and out-of-band) Protection criteria Intermodulation spurious response attenuation (dB) Antenna gain (dBd or dBi) Antenna height (m) Radiation pa
20、ttern Antenna polarization Depending on the type of system, additional characteristics for sharing studies may include: cell size or coverage area; down-tilt angle; feeder loss (if not already included in the antenna gain); required data rates; transmit power range due to power control; SNR targets
21、for uplink and downlink; propagation model (Note the applicable P-Series Recommendations listed in Annex 3). Rec. ITU-R M.1825 3 Annex 2 Methodologies for sharing related to systems operating in the land mobile service 1 Introduction The first step in any sharing study is to characterize the environ
22、ment, configuration, and conditions of the systems being analysed. Two types of conditions need to be considered: in-band analysis, where the systems share the same band and adjacent band analysis where the unwanted emissions of one system may impact the radio receivers in an adjacent band. Section
23、2 describes methodologies that can be used for sharing analyses involving the land mobile service and 3 describes mitigation techniques that can be used in some conditions in order to improve the ability to share the spectrum by the systems. 2 Methodologies for sharing studies There are two basic me
24、thodologies for sharing studies in the land mobile service: the link budget methodology and the Monte Carlo methodology. 2.1 Link budget methodology The maximum permitted equivalent isotropic radiated power (e.i.r.p.) level of an interfering signal may be determined by using the following simple equ
25、ation: EIRPMAX= IMAX GR() + LP+ LR where: EIRPMAX: the maximum permitted e.i.r.p. density of the interfering device (dBm/BREF), where a suitable reference bandwidth BREFneeds to be chosen IMAX: the maximum permissible interference power level at the receiver input, normalized (dBm/BREF) GR(): the vi
26、ctim receivers antenna gain in the direction of the interfering signal (dBi) LP: the propagation loss between transmitting and receiving antennas (dB), which may be a complex term depending upon environmental factors, some of which may be time-variant (e.g. fading) LR: the insertion loss (loss betwe
27、en the receiver antenna and receiver input) (dB). A zero dB may be assumed if no value is available. 2.2 Monte Carlo methodology The Monte Carlo methodology is capable of providing any desired level of mathematical accuracy and statistical validity and confidence to calculations of the probability o
28、f interference for any kind of radiocommunication system. Accuracy and statistical validity and confidence are limited by: a) how closely the mathematical model(s) describe the interference scenarios in consideration, and b) the number of trials done to calculate whether or not interference is prese
29、nt. The Monte Carlo methodology uses randomly generated values for uncertain variables, based on probability distributions applicable to these variables. The methodology combines a large number 4 Rec. ITU-R M.1825 of cases of independent variables and generates statistical results. A particular adva
30、ntage of using a Monte Carlo simulation is its ability to develop a statistical distribution of the predicted aggregate interference level (i.e. a cumulative distribution function) that takes into account the uncertainties of significant elements of the aggregate interference model, such as deployme
31、nt densities of interfering devices/systems, activity factors, etc. This methodology is therefore particularly useful when an estimate is desired of the probability that a certain aggregate interference power level is exceeded. The ITU-R has developed the Monte Carlo simulation methodology as a stat
32、istical tool for compatibility studies between radiocommunication services. An overview of this methodology is provided in Report ITU-R SM.2028-1. In addition, Recommendation ITU-R M.1634 describes the use of the Monte Carlo methodology for compatibility with the mobile service. For land mobile serv
33、ices the Monte Carlo simulation methodology assumes a victim receiver operating amongst a population of uniformly random distributed interferers. The desired signal level at the victim receiver can be calculated from the transmit power, antenna gains, and path loss. The effect of each interferer on
34、the victim receiver is determined using the transmit power, antenna gains, path loss, transmitter unwanted emission characteristic, receiver blocking and frequency separation. For some services, interference is considered to take place when the resultant C/I is less than the protection ratio. 3 Miti
35、gation techniques Pressure to make efficient use of the radio spectrum often means that radio systems are operated as close together in radio space as possible. To do this without reducing the reliability of these radio systems, interference mitigation techniques can be used. Mitigation reduces inte
36、rference and thereby the impact on an intended communication. Therefore, if used properly, mitigation helps different equipment and users to share the same frequency space. The possible mitigation techniques can be classified into four main types: SPEC: Methods related to specifications PERF: Equipm
37、ent performance (supplier improving the equipment performance) SESS: Site engineering on single site DEPL: Deployment relationship between sites. The following is a list of various existing interference mitigation techniques. Not all techniques are applicable to all types of systems, for example sit
38、e shielding can be helpful for fixed systems, but can not be used for mobile terminals. Similarly, some of these techniques are useful at both ends of an interfering link, while other techniques can only be applied to the interfering transmitter or to the victim receiver. Site selection Choosing a s
39、ite to minimize potential interference. (SESS, DEPL) Physical shielding Using natural terrain, buildings, special purpose fencing to block signal in undesired directions. (SESS) Antenna separation Coupling between two antennas located in the same site can be reduced by separating the antennas vertic
40、ally, horizontally or back-to-back by a few metres. (SESS) Antenna orientation Orienting the antenna of a directional, fixed system away from other radio systems. Physical constraints of system geometry often limit flexibility in antenna orientation. (SESS, DEPL) Rec. ITU-R M.1825 5 Antenna tilting
41、A special case of antenna orientation where the vertical antenna pattern and antenna down-tilt may be used to tailor coverage and hence reduce interference outside of the served area. Especially applicable to system base stations, but the effects on coverage may make this technique undesirable in ma
42、ny cases. (SESS, DEPL) Diversity combining A technique of coherently combining the signals from multiple antennas to produce a gain. (SESS) NOTE 1 Diversity combining uses all antenna elements at all times for each user, creating an antenna pattern that dynamically adjusts to the propagation environ
43、ment. Cross polarization The use of cross polarization can be used to introduce as much as 25-30 dB of discrimination. (DEPL) Frequency coordination Coordination of frequency selection between neighbouring systems so as to reduce the potential for interference. (DEPL) Synchronized time division The
44、mitigation brought by ensuring adjacent band systems synchronize their transmission and reception to avoid situations where a system is transmits during the time interval when the adjacent band system is receiving. (DEPL) Transmitter and receiver filtering Filtering is the ideal technique for avoidi
45、ng, causing, or receiving adjacent channel interference. (PERF) Smart antennas A smart antenna system combines multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. The benefit from the us
46、e of smart antennas on sharing is due to the fact that the RF energy radiated by antenna arrays is both lower than that from conventional antennas for the same e.i.r.p. and focused in limited, specific regions of a cell rather than wide sectors. (SPEC, PERF) NOTE 1 The two major categories of smart
47、antennas, based on the choice of transmit strategy, are adaptive antennas and switched-beam antennas. Dynamic channel selection techniques The radio system can potentially use one of a number of channels within a band for each transmission. The radio system listens on all of those channels to determ
48、ine which ones are occupied and dynamically chooses the channel to be used accordingly. Such techniques include for example Dynamic Frequency Selection, or Detect and Avoid mechanisms. (SPEC) Static channel selection techniques Before transmitting, the radio system listens on predetermined sub-chann
49、el(s) to determine whether a channel is appropriate for transmission. Such techniques include, for example, listen before talk or other static detect and avoid mechanisms. (SPEC) Frequency hopping The use of frequency hopping means that a radio system will only be using a particular frequency a small portion of the time and thus interference will only be caused or received for a brief moment and be unlikely to interfere with system operation. Dynamic frequency hopping goes a step further by eliminating channels from the hop s
