3GPP TS 37.461 V9.4.0: Iuant interface: Layer 1

3GPP TS 37.461 V9.4.0 (2019-04)
Technical Specification
3rd Generation Partnership Project;
Technical Specification Group Radio Access Network;
Iuant interface: Layer 1
(Release 9)


	 EMBED Word.Picture.8  
The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP. 
The present document has not been subject to any approval process by the 3GPP Organizational Partners and shall not be implemented. 
This Specification is provided for future development work within 3GPP only. The Organizational Partners accept no liability for any use of this Specification.
Specifications and reports for implementation of the 3GPP TM system should be obtained via the 3GPP Organizational Partners' Publications Offices.

Keywords
radio, EMC, power supply, antenna


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Contents
 TOC \o "1-9" Foreword	 PAGEREF _Toc6700765 \h 4
1	Scope	 PAGEREF _Toc6700766 \h 5
2	References	 PAGEREF _Toc6700767 \h 5
3	Definitions and abbreviations	 PAGEREF _Toc6700768 \h 5
3.1	Definitions	 PAGEREF _Toc6700769 \h 5
3.2	Abbreviations	 PAGEREF _Toc6700770 \h 5
4	Iuant layer 1	 PAGEREF _Toc6700771 \h 6
4.1	General	 PAGEREF _Toc6700772 \h 6
4.2	RS485 option	 PAGEREF _Toc6700773 \h 7
4.3	Modem option	 PAGEREF _Toc6700774 \h 7
4.3.1	Interference with existing systems	 PAGEREF _Toc6700775 \h 9
4.3.1.1	Carrier frequency and frequency stability	 PAGEREF _Toc6700776 \h 9
4.3.1.2	Modem isolation and modem emissions	 PAGEREF _Toc6700777 \h 9
4.3.1.3	Modem intermodulation attenuation	 PAGEREF _Toc6700778 \h 10
4.3.2	Recovery time	 PAGEREF _Toc6700779 \h 10
4.3.3	Impedance	 PAGEREF _Toc6700780 \h 10
4.3.4	Modulator characteristics	 PAGEREF _Toc6700781 \h 11
4.3.4.1	Levels	 PAGEREF _Toc6700782 \h 11
4.3.4.2	Spectrum emission mask	 PAGEREF _Toc6700783 \h 11
4.3.5	Demodulator characteristics	 PAGEREF _Toc6700784 \h 11
4.3.6	Duty cycle variation	 PAGEREF _Toc6700785 \h 11
4.3.7	Operating bands	 PAGEREF _Toc6700786 \h 12
4.3.8	 Time delay and accuracy	 PAGEREF _Toc6700787 \h 13
4.3.9	 Insertion Loss	 PAGEREF _Toc6700788 \h 13
4.3.10	DC port isolation	 PAGEREF _Toc6700789 \h 13
4.3.11	RET control unit spurious emission	 PAGEREF _Toc6700790 \h 14
4.3.12	Control unit spurious emission	 PAGEREF _Toc6700791 \h 14
4.4	DC power supply	 PAGEREF _Toc6700792 \h 14
4.4.1	Power consumption	 PAGEREF _Toc6700793 \h 14
4.4.2	Conducted emission	 PAGEREF _Toc6700794 \h 15
4.4.3	Power-up characteristics	 PAGEREF _Toc6700795 \h 15
Annex A (normative):	Test procedures	 PAGEREF _Toc6700796 \h 16
Annex B (informative):	Change history	 PAGEREF _Toc6700797 \h 17

Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x	the first digit:
1	presented to TSG for information;
2	presented to TSG for approval;
3	or greater indicates TSG approved document under change control.
y	the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc.
z	the third digit is incremented when editorial only changes have been incorporated in the document.
1	Scope
The present document specifies the standards allowed to implement layer 1 on the Iuant interface for UTRA & E-UTRA.
The specification of transmission delay requirements and O&M requirements are not in the scope of the present document.
2	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 TS 37.462: "Iuant interface: Signalling transport".
[2]	ISO/IEC 8482 (1993): "Information technology - Telecommunications and information exchange between systems - Twisted pair multipoint interconnections".
[3]	TIA/EIA TSB89: “Application guidelines for TIA/EIA-485-A”.
3	Definitions and abbreviations
3.1	Definitions
For the purposes of the present document, the following terms and definitions apply:
On-Off-Keying: A modulation system in which a carrier is switched between two states, ON and OFF.
Common feeder cable: Feeder cable where some antenna line devices (e.g. RET, TMA) are connected via the same feeder cable.
3.2	Abbreviations
For the purposes of the present document, the following abbreviations apply:
BS	Base Station
DC	Direct Current
DL	Downlink
FDD	Frequency Division Duplex
ISB	Idle-State Biasing
OOK	On-Off-Keying
RET	Remote Electrical Tilting
RF	Radio Frequency
TMA	Tower Mounted Amplifier
UE	User Equipment
UL	Uplink
UMTS	Universal Mobile Telecommunications System
UTRA	UMTS Terrestrial Radio Access
4	Iuant layer 1
4.1	General
There are two layer 1 options:
-	RS485 option: A screened multicore cable, which supports a conventional RS485 serial multi-drop bus.
-	Modem option: A connection to a RET and/or a TMA control unit by way of a coaxial cable which is shared with DC supply and RF signals.
Both layer 1 options support the connection of two-way serial data and DC power to the RET and/or TMA antenna device.
At least one of these two layer 1 options shall be supported.
The default data rate for both layer 1 options shall be 9.6 kbps. Higher data rates of 38.4 kbps for both layer 1 options and 115.2 kbps only for the RS485 layer 1 option may optionally be supported. Each unit communicates on one of the three data rates, but different units on the same interface may use different data rates.
After a reset, a secondary device shall alternate between supported data rates. When alternating between data rates, the data rate shall be held constant for 300 ms. After every correctly received device scan command (see TS 37.462 [1]) independent of whether it matches or not, at one of the supported data rates, that data rate shall be held constant for 1.5 seconds. After successful reception of an address assignment frame, the secondary device shall use that data rate until it is reset.
Data rates:
-	9.6 kbps ± 3 %
-	38.4 kbps ± 3 %
-	115.2 kbps ± 3 %
The format of the data octet shall be as shown in figure 4.1.1:
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Figure 4.1.1: Format and order of transmitted data
4.2	RS485 option
This option is constituted by a two wire bi-directional multi-drop configuration conforming to ISO/IEC 8482 [2]. The mapping of mark/space to logical one and zero as referred to in ISO/IEC 8482 [2] shall be according to figure 4.1.1.
The use of ISB, also called idle-line failsafe in TIA/EIA TSB89 [3], is mandatory. The bias voltages shall be applied only by the primary device to any separate RS485 bus. The polarity of the idle-state bias is defined as a transmitted 1.
The RS485 transmitter shall be set to drive the bus before the first start bit is sent and held active until the last stop bit is sent. The RS485 transmitter shall stop driving the bus within 20 bit-times after the last stop bit is sent.
If an antenna modem is used ISB shall be implemented by the antenna modem.
4.3	Modem option
The connection to a RET and/or a TMA control unit by way of a coaxial cable which is shared with DC supply and RF signals is provided by two modems, a BS modem and an antenna modem. The BS modem shall be either connected to the antenna connector of the BS or integrated in the BS. It provides signal transmission to the antenna modem and signal reception from the antenna modem over the antenna feeder cable. The antenna modem is located between the antenna feeder cable and the antenna. Modem configurations and reference points for modem characteristics are specified in figure 4.3.1 and figure 4.3.2. Unless otherwise stated, requirements in this section apply to both BS modem and antenna modem.
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Figure 4.3.1: Modem configuration and modem reference points for a BS without BS modem

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Figure 4.3.2: Modem configuration and modem reference points for
a BS with integrated BS modem
4.3.1	Interference with existing systems
The modem circuit shall be capable of managing its transmitting characteristic according to subclause 4.3.5.
4.3.1.1	Carrier frequency and frequency stability
The following carrier frequency shall be used for this application:
	2.176 MHz ± 100 ppm
4.3.1.2	Modem isolation and modem emissions
The external BS modem shall provide minimum attenuation according to figure 4.3.1.2.1 between reference point 2 and reference point 1 to protect the BS from emissions of the antenna modem.
External BS modem emissions at reference point 1 shall be attenuated at least according to the modem attenuation in figure 4.3.1.2.1 below the levels specified for the modem spectrum emission mask in subclause 4.3.4.2 to protect the BS from emissions of the BS modem.
The antenna modem shall provide minimum attenuation according to figure 4.3.1.2.1 between reference point 3 and reference point 4 to protect other radio systems from emission of the BS modem.
Antenna modem emissions at reference point 4 shall be attenuated at least according to the modem attenuation in figure 4.3.1.2.1 below the levels specified for the modem spectrum emission mask in subclause 4.3.4.2 to protect other radio systems from emission of the antenna modem.
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Figure 4.3.1.2.1: Modem attenuation
4.3.1.3	Modem intermodulation attenuation
The modem intermodulation attenuation is specified in terms of the power in intermodulation products of WCDMA modulated carriers present at reference point 1 or reference point 3.
For 2 downlink carriers of 43 dBm the power of third order intermodulation products in the UL operating bands for the external BS modem and antenna modem shall not exceed:
-	– 130 dBm/100 kHz for frequencies < 1 GHz
-	– 120 dBm/1 MHz for frequencies ≥ 1 GHz
NOTE: 	Using the modem with higher power than 43 dBm and or with more carriers than 2 carriers at 43dBm/carrier may increase intermodulation products and may degrade the receiver sensitivity of the BS if these intermodulation products fall at BS receive frequencies. 
For the worst input configuration of power and number of carriers declared by the modem manufacturer the power of any intermodulation product for the external BS modem and antenna modem shall not exceed:
-	– 98dBm/100kHz
In addition, for the worst input configuration of power and number of carriers declared by the modem manufacturer the power of fifth or higher order intermodulation products in the UL operating bands for the external BS modem and antenna modem shall not exceed:
-	– 135 dBm/100 kHz for frequencies < 1 GHz
-	– 125 dBm/1 MHz for frequencies ≥ 1 GHz
4.3.2	Recovery time
A minimum recovery time shall be allowed between receiving and transmitting messages on the bus. For this reason a minimum permitted response time is specified in subclause 4.5 in TS 37.462 [1].
4.3.3	Impedance
The modem transceiver shall provide constant impedance in both transmitting and receiving modes:
-	Nominal impedance Z0: 50 Ω;
-	Return loss at modem carrier frequency ± 0.1 MHz > 10 dB;
-	Return loss in external BS and antenna modem operating bands > 20 dB.
4.3.4	Modulator characteristics
4.3.4.1	Levels
ON-Level:	+3 dBm ± 2 dB
OFF-Level:	≤ -40 dBm
4.3.4.2	Spectrum emission mask
The modem spectrum emission mask is specified in figure 4.3.4.2.1. Intermediate values may be obtained by linear interpolation between the points shown. The corresponding measurement bandwidths are specified in table 4.3.4.2.1. For modem configurations according to figure 4.3.1 the BS modem emissions shall not exceed the limits of the spectrum emission mask at reference point 2. For modem configurations according to figure 4.3.2 the BS with integrated BS modem emissions shall not exceed the limits of the spectrum emission mask at reference point 2 only for frequencies below 20 MHz. Antenna modem emissions shall not exceed the limits of the spectrum emission mask at reference point 3.
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Figure 4.3.4.2.1: Modem spectrum emission mask.
Note 1:	For frequencies <1GHz the general emission limit is -108dBm, except modem operating band UL frequencies where the emission limit is -135 dBm.
For frequencies ≥1GHz the general emission limit is -98dBm, except modem operating band UL frequencies where the emission limit is -125 dBm.
Table 4.3.4.2.1: Modem spectrum emission mask measurement bandwidth
Band
Measurement Bandwidth
9 kHz - 150 kHz
1 kHz
150 kHz - 30 MHz
10 kHz
30 MHz - 1 GHz
100 kHz
1 GHz - 12.75 GHz
1 MHz

4.3.5	Demodulator characteristics
The demodulator shall fulfil the requirement in subclause 4.3.6 for a carrier ON-Level within +5 dBm to -12 dBm and a carrier OFF-Level less than -18 dBm. The levels within –12 dBm to –18 dBm are undefined.
4.3.6	Duty cycle variation
In order to guarantee proper transmission of data bits through the processes of modulation and demodulation, the following limit shall be met for the duty cycle variation:
ΔDCSYSTEM = |DCRX – DCTX| ≤ 10 %
Where:	ΔDCSYSTEM is the difference between the duty cycles of the transmitted and received bit streams,
	DCTX = Duty cycle for the input bit stream, and
	DCRX = Duty cycle for the output bit stream.
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Figure 4.3.6.1: Duty cycles of the bit stream and OOK modulated subcarrier
For transmission through a coaxial cable, two converters are required, one from a bit stream to OOK (modulator) and one from OOK back to a bit stream (demodulator). Therefore half of the total duty cycle tolerance is available for each converter.
For an input bit stream with a duty ratio of 50 %, the cascaded modulator and demodulator shall provide an output bit stream with a duty ratio within the limits 40 % - 60 %, measured in each case at 0.5 times peak amplitude (see figure 4.3.6.1).
4.3.7	Operating bands
A UTRA/FDD BS, UTRA/TDD BS, E-UTRA BS or antenna modem is designed to operate in one or several of the following frequency bands:
Table 4.3.7.1: Frequency bands
UTRA Operating Band
E-UTRA Operating Band
UL operating band
UE transmit, BS receive
DL operating band
UE receive, BS transmit
I
1
1920 – 1980 MHz
2110 – 2170 MHz
II
2
1850 –1910 MHz
1930 – 1990 MHz
III
3
1710 – 1785 MHz
1805 – 1880 MHz
IV
4
1710 – 1755 MHz
2110 – 2155 MHz
V
5
824 – 849 MHz
869 – 894 MHz
VI
6 Note 1
830 – 840 MHz
875 – 885 MHz
VII
7
2500 – 2570 MHz
2620 – 2690 MHz
VIII
8
880 – 915 MHz
925 – 960 MHz
IX
9
1749.9 – 1784.9 MHz
1844.9 – 1879.9 MHz
X
10
1710 – 1770 MHz
2110 – 2170 MHz
XI
11
1427.9 - 1447.9 MHz
1475.9 - 1495.9 MHz
XII
12
699 – 716 MHz
729 – 746 MHz
XIII
13
777 – 787 MHz
746 – 756 MHz
XIV
14
788 – 798 MHz
758 – 768 MHz
XV
15
Reserved
Reserved
XVI
16
Reserved
Reserved
XVII Note 2
17
704 – 716 MHz
734 – 746 MHz
XVIII Note 2
18
815 – 830 MHz
860 – 875 MHz
XIX
19
830 – 845 MHz
875 – 890 MHz
XX
20
832 - 862 MHz
791 - 821 MHz
XXI
21
1447.9 - 1462.9 MHz
1495.9 - 1510.9 MHz

…


a)
33
1900 –	1920 MHz
1900 –	1920 MHz
a)
34
2010 – 2025 MHz
2010 – 2025 MHz
b)
35
1850 – 1910 MHz
1850 – 1910 MHz
b)
36
1930 –	 1990 MHz
1930 –	 1990 MHz
c)
37
1910 –	 1930 MHz
1910 –	 1930 MHz
d)
38
2570 –	 2620 MHz
2570 –	 2620 MHz
f)
39
1880 –	 1920 MHz
1880 –	 1920 MHz
e)
40
2300 –	 2400 MHz
2300 –	 2400 MHz
Note 1: Band 6 is not applicable.
Note 2: UTRA Operating Band XVII and XVIII are Reserved.

The operating bands of the BS modem or antenna modem shall be declared by the manufacturer.
4.3.8		Time delay and accuracy
The time delay in the operating bands shall be declared by the manufacturer with ± 1 ns accuracy. The time delay shall not exceed 30 ns. This requirement is only applicable to external BS modem and antenna modem.
4.3.9		Insertion Loss
The insertion loss in the external BS modem or antenna modem operating band shall be ≤ 0.3 dB.
The actual insertion loss shall be declared by the manufacturer.
4.3.10	DC port isolation
The isolation between DC port and RF ports shall meet the minimum values in figure 4.3.10.1 and 4.3.10.2. Figure 4.3.10.1 is valid for antenna modems between reference point 5 and 4 as well as 5 and 3 and for BS modems without integrated power supply between reference point 6 and 2 as well as 6 and 1. Figure 4.3.10.2 is valid as additional requirement for antenna modems between reference point 5 and 3 and for BS modems without integrated power supply between reference point 6 and 2.
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Figure 4.3.10.1: DC port isolation
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Figure 4.3.10.2: DC port isolation
4.3.11	RET control unit spurious emission
Void.
4.3.12	Control unit spurious emission
The control unit, or a combination of control units, shall not generate spurious emission, at reference point 5, above a level that will violate the spectrum emission mask requirement according to chapter 4.3.4.2. The DC port isolation according to chapter 4.3.10 shall be taken into account.
4.4	DC power supply
4.4.1	Power consumption
The DC supply requirements refers to reference points 3 and 5 in subclause 4.3.
BS modem and an antenna modem shall be able to operate with a DC supply voltage range of 10 V – 30 V.
Power consumption modes are specified in table 4.4.1.1. and table 4.4.1.2.
Table 4.4.1.1: Power consumption modes for RET
RET Power mode
Maximum power consumption
High
< 13 W
Low
< 2 W

Table 4.4.1.2: Power consumption modes for TMA
TMA Type
Maximum power consumption
Single Unit
< 7,5 W
Multi Unit (N)
< N * 7,5 W

BS modem and antenna modem maximum power consumption shall be < 2 W.
BS modem and antenna modem shall impose a voltage drop less than 2 V between reference point 3 and 5.
A Single Unit considers one RF amplifier in one TMA. A Multi Unit considers N RF amplifiers in equal or less than N TMAs.
4.4.2	Conducted emission
The levels of generated conducted noise and ripple on DC Power supply shall be within the limits given in table 4.4.2.1.
Table 4.4.2.1: Noise and ripple
Item
Limit
Frequency
Remarks
RET power mode High
70 mVpp
0.15 - 30 MHz
Only one operating unit a time
RET power mode Low
20 mVpp
0.15 - 30 MHz

TMA
20 mVpp
0.15 - 30 MHz

Antenna modem, RF port
15 mVpp
0.15 - 30 MHz
Generated Noise and Ripple at RF feeder (in RX mode)
Antenna modem, DC port
20 mVpp
0.15 - 30 MHz
Allowed Noise and Ripple at external DC port (in TX mode)

All units connected to a DC supply bus shall exhibit full performance up to the limit of 112 mVpp total noise and ripple within 0.15 - 30 MHz.
4.4.3	Power-up characteristics
A BS modem, antenna modem or RET/TMA control units shall have a power-up period of 3 s.
During the power-up period a BS modem, antenna modem or a RET control unit shall exhibit the circuit equivalent of a DC power consumer with a current consumption of maximum 400 mA in parallel with a capacitor of maximum 0.5 µF.
During the power-up period the TMA control unit shall exhibit the circuit equivalent of a DC power consumer with a current consumption of maximum 1A in parallel with a capacitor of maximum 0.5 µF.
After the power-up period, the unit shall be fully functional and the power consumption requirement as described in subclause 4.4.1 applies.

Annex A (normative):
Test procedures
Test pattern
Spectrum mask and emission requirement shall be tested both with a consecutive series of “0” and an alternating sequence of “0” and “1”.
Emission requirement below noise floor
As a general rule, the resolution bandwidth of the measuring equipment should be equal to the measurement bandwidth. However, to improve measurement accuracy and sensitivity when measuring close to or below the noise floor, the resolution bandwidth may be smaller than the measurement bandwidth. When the resolution bandwidth is smaller than the measurement bandwidth, the result should be integrated over the measurement bandwidth in order to obtain the equivalent noise bandwidth of the measurement bandwidth.

Conversion between modulated and CW for IM measurement
The requirement for IM3 below 1 GHz shall be relaxed 15 dB and tested with CW interferers at the specified levels.
The requirement for IM3 above 1 GHz shall be relaxed 5 dB and tested with CW interferers at the specified levels.
The requirement for IM5 or higher below 1 GHz shall be relaxed 10 dB and tested with CW interferers at the specified levels.
The requirement for IM5 or higher above 1 GHz shall be relaxed 0 dB and tested with CW interferers at the specified levels.
Example: A –130 dBm/100 kHz requirement below 1 GHz with two WCDMA-modulated carriers at 43 dBm is converted to a –115 dBm requirement with two CW carriers at 43 dBm.
Annex B (informative):
Change history
Change history
DateMeetingTDocCRRevCatSubject/CommentNew version2019-02R3-103R3-190081Text transferred from 25.461 v9.3.1 (changes shown with rev marks)1.9.02019-04RAN#83RP-190584Specification approved by RAN plenary9.4.0








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 STYLEREF ZGSM Release 9


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