GB 6281-1986 Co-channel interference standards required for land mobile services (16KOF3E)

This standard specifies the radio frequency protection ratio (i.e. co-channel interference protection ratio) and co-channel interference mode between systems required by my country's land mobile service (16k0F3E) in the VHF and UHF bands. It can be used by the national level-free frequency management agencies and mobile communication network planning and system design departments. GB 6281-1986 Co-channel interference standard required by land mobile service (16KOF3E) GB6281-1986 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Co-channel interference standardsrequired in the land mobile
services (16k0F3E)
UDC 621.895.74
GB 6281-86
This standard specifies the radio frequency protection ratio (i.e. co-channel interference protection ratio) and the co-channel interference mode between systems required by my country's land mobile services (16k0F3E) in the VHF and UHF frequency bands. It can be used by radio frequency authorities at all levels and mobile communication network planning and system design departments across the country.
RF protection ratio**
1.1 RF protection ratio definition:
The minimum power ratio between the useful signal and the unwanted signal required at the input end of the receiver under the condition that the useful signal output by the receiver reaches the specified reception quality***. 1.2 RF protection ratio when the carrier frequencies of the useful signal and the unwanted signal are the same: Useful signal
Unwanted signal
RF protection ratio (dB)
16k0F3E
16k0F3E
1.3 RF protection ratio when the carrier frequencies of the useful signal and the unwanted signal deviate: The carrier frequency difference between the useful signal (16k0F3E) and the unwanted signal (16k0F3E) (kHz)5
2 Radio frequency protection ratio of co-channel interference mode for frequency coordination (dB)
In the same region, adjacent regions, and border regions of adjacent countries, the co-channel interference mode used for frequency coordination of land mobile services is specified as follows:
*16k0F3E means as follows:
16k0--transmission bandwidth is 16kHzz
F——the modulation mode of the main carrier is frequency modulation, 3——single channel containing mode information
E——telephone.
**It is formulated based on the test results in the laboratory. Under actual business conditions, the influence of multipath propagation, terrain undulation and artificial noise should be considered. See Appendix A.
***The reception quality specified in this standard is S/N=14dB. According to the subjective evaluation test, the signal quality when S/N=14dB belongs to the 3-point level in the 5-level scoring system (that is, the 3-level signal quality, the voice is understandable, and the interference noise is annoying), and it is generally believed that the 3-level signal quality corresponds to the signal quality required for the minimum acceptable service level. Issued by the National Bureau of Standards on April 14, 1986
Implementation on April 1, 1987
GB 6281—86
ED (50, 50) (L, T) - Eu (50, 10) (L, T) ≥8 (dB) .......... (1) In the formula: Ep (50, 50) (L, T) is the median field strength of the useful signal, whose location probability (L) and time probability (T) are both 50%
Eu (50, 10) (L, T) is the field strength of the unwanted signal, whose location probability (L) and time probability (T) are 50% and 10% respectively.
Similarly, when the carrier frequencies of the wanted signal and the unwanted signal deviate, the interference pattern is defined as E(50,50)(L,T)-Eu(50,10)(L,T)≥R(dB)) where: R is the radio frequency protection ratio corresponding to the carrier frequency difference between the wanted signal and the unwanted signal, see 1.3. 3 Scope of application of this standard
This standard applies to all types of users of terrestrial private and public mobile communications (16k0F3E) who require an acceptable minimum service level. For individual special users, they may be considered separately with the approval of the national radio frequency authority. 2
GB 6281—86
Appendix A
Explanation for the use of the standard
(reference)
This standard is based on the test results under static conditions (only the thermal noise of the receiver) and relevant CCIR documents. In actual use, the impact of multipath fading (fast fading) and man-made noise on voice quality should be considered; at the same time, the impact of terrain fading (slow fading) caused by terrain undulations and building changes on communication reliability should also be considered. Therefore, it is necessary to explain the calculation of the minimum protection field strength and co-channel interference.
A.1 Minimum protection field strength
In land mobile communications, the reception performance of the receiver is deteriorated due to the influence of multipath propagation effects and man-made noise (mainly car spark interference). In order to obtain the same voice quality level as under static conditions, the useful signal level input to the receiver must be increased. The increased value is the deterioration caused by multipath propagation effects and artificial noise, and the required field strength is the minimum protection field strength, calculated as follows:
Emin = - 4l+d+ 20 lg f dB(μV/m). In the formula: Emi-bzxZ.net
·（A1）
-minimum protection field strength (the receiving antenna is a half-wave dipole antenna, and the receiver sensitivity is 0.7μVe·m·f·)——frequency (MHz);
d—deterioration (dB), and its values ​​are shown in Figures A1 and A2. 30
(ap)po
500(MHz）
Figure A1
The relationship between the degradation of receiving performance and the change of frequency when the mobile station receives (the sensitivity of the receiver with level 3 signal quality is 0.7μVe·m·f.)A-the moving car is parked in the high noise area*,B-the moving car is driving in the high noise area,C-the moving car is driving in the low noise area**
*The high noise area is defined as the traffic density of 100 vehicles/km2 at any time,*The low noise area is defined as the traffic density of 1 vehicle/km2 at any time.3
GB 6281-86
1000f(MHz）
The relationship between the deterioration of receiving performance and the change of frequency when the base station receives A2
(Level 3 signal quality, receiver sensitivity is 0.7μVe·m·f.) A-The moving car is moving, the traffic volume is 2 cars/s, B-The moving car is moving, the traffic volume is 1 car/s; C-The moving car is moving, there is no spark or environmental noise interference; D-The moving car is stationary, the traffic volume is 2 cars/sE-The moving car is stationary, the traffic volume is 1 car/sA.2 Distribution of median field strength with position and time Many test results indicate that the distribution of the median field strength of the received signal with position and time in a large range obeys the log-normal distribution. If the standard deviations of the distribution are recorded as and t respectively, then the joint standard deviation = +? . The values ​​of and t are listed in the following table.
Standard deviation L and at
dL(dB)
Quasi-flat terrain
Suburban area and small hills
Urban area
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