SRSP-331.8 — Technical Requirements for Fixed Radio Systems Operating in the Band 31.8-33.4 GHz

Issue 1
March 2021

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Preface

Issue 1 of SRSP-331.8 has been developed to reflect Innovation, Science, and Economic Development Canada's SMSE-022-14, Decisions on Spectrum Utilization Policies and Technical Requirements Related to Backhaul.

Issued under the authority of
the Minister of Innovation, Science and Industry

Martin Proulx
Director General
Engineering, Planning and Standards Branch

1. Intent

This Standard Radio System Plan (SRSP) states the minimum technical requirements for the efficient use of the frequency band 31.8-33.4 GHz by point-to-point, digital line-of-sight radio systems in the fixed service.

This SRSP is intended to be used in the design and specification of radio systems and equipment, as well as in the technical evaluation of applications for new radio facilities or modifications to radio systems submitted in accordance with the current issue of Radio Standards Procedure RSP-113, Application Procedures for Planned Radio Stations Above 960 MHz in the Fixed Service.

This SRSP specifies system requirements related to efficient spectrum usage only and is not to be regarded as a comprehensive specification for equipment design and/or selection.

2. General

This section describes general requirements related to licensing, compliance of radio systems, resolution of interference conflicts between radio systems and spectrum sharing.

2.1 Licensing process

Systems deployed in the frequency band 31.8-33.4 GHz must conform to the requirements of this standard and be coordinated in accordance with RSP-113.

2.2 Compliance of radio systems

Radio systems conforming to these technical requirements will be given priority in licensing over non-standard radio systems operating in this band.

The arrangements for non-standard systems are outlined in Spectrum Utilization Policy SP Gen, General Information Related to Spectrum Utilization and Radio Systems Policies.

Even though a radio system conforms to the requirements of this SRSP, modifications may be required to the system whenever harmful interference, as defined in the Radiocommunication Act, is caused.

2.3 Resolution of interference conflicts between radio systems

When potential or real conflicts between radio systems cannot be resolved by the parties concerned, Innovation, Science and Economic Development Canada (ISED) should be advised. After consultation with these parties, ISED will determine the necessary modifications and schedule of modifications to resolve the interference conflict.

In cases of a potential interference conflict, among other potential mitigation measures, ISED may require licensees and/or applicants to use a receiver with improved selectivity characteristics.

2.4 Spectrum sharing

It should be noted that the fixed service shares this frequency band with other services in accordance with the Canadian Table of Frequency Allocations.

3. Related documents

The current issues of the following documents are applicable and available on ISED’s Spectrum Management and Telecommunications website, under Official publications:








Acronyms

CPC — Client Procedures Circular

RSP — Radio Standards Procedure

SMSE — Spectrum Management Spectrum Engineering

SP — Spectrum Utilization Policy

TRC — Telecommunications Regulation Circular

4. Radio frequency (RF) channel arrangement description

This section describes the RF channel arrangements for point-to-point digital radio systems.

4.1 RF channel arrangements for the frequency band 31.8-33.4 GHz

Channel pairs are provided with a common transmit/receive separation of 812 MHz. The five different channel plan bandwidths are:

  • 14 MHz
  • 28 MHz
  • 56 MHz
  • 112 MHz
  • 224 MHz

A radio system must operate with an occupied bandwidth less than or equal to one of the permitted channel plan bandwidths given above. Occupied bandwidth or the “99% emission bandwidth” is defined as the frequency range between two points, one above and the other below the carrier frequency, within which 99% of the total transmitted power of the fundamental transmitted emission is contained.

14 MHz channel plan bandwidth

The centre frequencies of the 54 paired channels, which allow occupied bandwidths less than or equal to 14 MHz, are expressed by the following relationships:

Lower half of the band 
Upper half of the band 
An = 31808 + 14n
An' = 32620 + 14n
for n = 1 to 54
for n = 1 to 54

Where n is the channel number, and An and An' are the centre frequencies in MHz of the paired channels.

28 MHz channel plan bandwidth

The centre frequencies of the 27 paired channels, which allow occupied bandwidths greater than 14 MHz and less than or equal to 28 MHz, are expressed by the following relationships:

Lower half of the band 
Upper half of the band 
Bn = 31801 + 28n
Bn' = 32613 + 28n
for n = 1 to 27
for n = 1 to 27

Where n is the channel number, and Bn and Bn' are the centre frequencies in MHz of the paired channels.

56 MHz channel plan bandwidth

The centre frequencies of the 12 paired channels, which allow occupied bandwidths greater than 28 MHz and less than or equal to 56 MHz, are expressed by the following relationships:

Lower half of the band 
Upper half of the band
Cn = 31843 + 56n
Cn' = 32655 + 56n
for n = 1 to 12
for n = 1 to 12

Where n is the channel number, and Cn and Cn' are the centre frequencies in MHz of the paired channels.

112 MHz channel plan bandwidth

The centre frequencies of the 6 paired channels, which allow occupied bandwidths greater than 56 MHz and less than or equal to 112 MHz, are expressed by the following relationships:

Lower half of the band
Upper half of the band
Dn = 31815 + 112n
Dn' = 32627 + 112n
for n = 1 to 6
for n = 1 to 6

Where n is the channel number, and Dn and Dn' are the centre frequencies in MHz of the paired channels.

224 MHz channel plan bandwidth

The centre frequencies of the 3 paired channels, which allow occupied bandwidths greater than 112 MHz and less than or equal to 224 MHz, are expressed by the following relationships:

Lower half of the band 
Upper half of the band
En = 31759 + 224n
En' = 32571 + 224n
for n = 1 to 3
for n = 1 to 3

Where n is the channel number, and En and En' are the centre frequencies in MHz of the paired channels.

4.2 Frequency planning

Systems are required to be designed using a two-frequency plan (i.e. typically no more than one frequency in each direction along a route). Where reasonable justification is provided (e.g. where siting prevents adequate antenna discrimination), extra frequencies beyond the standard two may be used to resolve the problem.

4.3 Branching or spur route channels

The frequencies used on a main route system should be reused on the branching or spur routes where possible. The siting of repeater stations should be planned with this requirement in mind to ensure sufficient antenna discrimination at the branch-off angle.

4.4 Closed loops

When point-to-point digital radio systems form a closed loop, such systems shall be designed to consist of an even number of hops to permit the use of two-frequency plans.

4.5 Assignment of frequencies

Fixed service systems should normally use the lowest available frequency pair that can be successfully coordinated. However, due to varying conditions and circumstances across Canada, ISED’s regional offices may assign frequencies using a procedure different from the one described above, at their own discretion.

5. Transmitter characteristics

This section describes the transmitter characteristics for point-to-point digital radio systems.

5.1 Transmitter power limits

The transmitter power delivered to the antenna input per RF channel shall not exceed 10 watts (+10 dBW) within the occupied bandwidth. Furthermore, the power spectral density delivered to the antenna input shall not exceed -1.46 dBW/MHz.

In the case of systems using automatic transmit power control (ATPC) to maintain link availability during deep fading conditions, the transmitter power at the antenna port may be temporarily increased by a value corresponding to the ATPC range, up to a maximum of 10 watts. In addition, the maximum equivalent isotropically radiated power (e.i.r.p.) limit indicated in section 7 of this document shall be met at all times.

5.2 Frequency stability

The centre frequency of the emission shall be maintained within ±0.001% of the assigned frequency.

5.3 Transmitter emissions

Emission mask

For frequencies removed from the carrier centre frequency by more than or equal to 47.04 % and less than or equal to 250% of the channel plan bandwidth, the power spectral density of emission shall be attenuated below the power spectral density at the channel centre frequency in accordance with figure 1 and table 1. The attenuation values are specified at frequencies removed from the assigned channel centre frequency as a percentage of the channel plan bandwidth.

Figure 1: Emission mask

Figure 1: Emission mask
Description of figure 1

This line graph shows the attenuation in dB at which the power spectral density shall be attenuated as frequencies are removed from the carrier center. The yaxis measures the attenuation in dB from 0 to 50. The xaxis plots the frequency separation from the assigned channel center frequency as a percentage of the channel plan bandwidth from 0 to 250.

There is only one data line. The line ranges from 0 to 45 on the yaxis. Five data points for the line are shown in table 1, with a straight line interconnecting each adjacent point. The attenuation must exceed these limits.

Table 1: Emission mask
Attenuation (dB) Frequency separation (% of channel plan bandwidth)
0 47.04
23 59
23 89
45 161
45 250
Note: The above emission mask is aligned with the Class 1, 2, 3 specifications prescribed by the European Telecommunications Standards Institute standard ETSI EN 302 217-2 V3.2.2 (2020-02), Fixed Radio Systems; Characteristics and requirements for point-to-point equipment and antennas; Part 2: Digital systems operating in frequency bands from 1 to 86 GHz; Harmonised standard for access to radio spectrum.

Spurious emission limit

For frequencies removed from the carrier centre frequency by more than 250% of the channel plan bandwidth, the power spectral density of emission delivered to the antenna input shall not exceed -30 dBm/MHz.

Note: The spurious emission limit is aligned with ETSI EN 301 390 V1.3.1 (2013-08), Fixed Radio Systems; Point-to-point and Multipoint Systems; Unwanted emissions in the spurious domain and receiver immunity limits at equipment/antenna port of Digital Fixed Radio Systems.

Adjacent band emission limit

Additionally, emissions into the adjacent frequency band 31.3-31.8 GHz are furthermore limited. The power spectral density, delivered to the antenna input, shall be limited to a maximum of -37.4 dBW/100 MHz below 31.8 GHz in order to protect the Earth exploration-satellite service (EESS) (passive), which has a primary allocation in the adjacent frequency band 31.3-31.8 GHz. Recommendation ITU-R SM. 1633-0 Compatibility analysis between a passive service and an active service allocated in adjacent and nearby bands, Annex 16, was used as guidance material in the consideration of EESS operating in the adjacent frequency band.

5.4 Spectral efficiency

Digital systems submitted for licensing shall meet a minimum spectral efficiency of 1.14 bits/s/Hz on a single polarization in a bandwidth corresponding to the channel plan bandwidth.

In the case of systems using adaptive modulation or adaptive error-correction coding to maintain link availability during deep fading conditions, the spectral efficiency level may be temporarily lowered for a short period of time, provided that the link is designed to meet the minimal spectral efficiency requirements specified in the provisions above.

6. Antenna characteristics

The co-polarized radiation pattern envelope in the horizontal and vertical planes of the antenna must remain within the envelope shown in figure 2 and table 2, for both vertical and horizontal polarizations.

Figure 2: Minimum antenna characteristics for point-to-point digital radio systems operating in the frequency band the 31.8-33.4 GHz

Figure 2: Minimum antenna characteristics for point-to-point digital radio systems operating in the frequency band the 31.8-33.4 GHz
Description of figure 2

This line graph shows the antenna radiation pattern limits for point-to-point digital radio systems operating in the band 31.8-33.4 GHz. The x-axis plots azimuth and elevation in degrees from the main lobe from 0 to 180. The y-axis measures antenna directivity in dB down from the main lobe from 0 to 80.

There is only one data line. The data line for the envelope ranges from 0 to 55 on the y-axis. There is a scale change indicator at the 20 mark on the x-axis. The measured radiation pattern in the horizontal and vertical planes must be within these limits for vertical and horizontal polarizations. Ten data points for the data line are shown in table 2, with a straight line interconnecting each adjacent point.

Table 2: Minimum antenna characteristics for point-to-point digital radio systems operating in the frequency band the 31.8-33.4 GHz
Azimuth and elevation in degrees from main lobe Antenna directivity in dB down from main lobe
0 0
5 0
5 18
10 27
15 32
20 38
50 39
70 42
90 55
180 55

7. Maximum equivalent isotropically radiated power

The maximum e.i.r.p. from the antenna must not in any case exceed +55 dBW per RF channel.

8. International coordination

Canada does not currently have a formal arrangement with the United States (US) government for sharing of the 31.8-33.4 GHz frequency band along the border regions. Licensees will be subject to any future agreements between Canada and the US regarding use of these systems in the border regions, which may include modifications of previously authorized stations.

In the absence of a formal arrangement with the US government for sharing of the 31.8-33.4 GHz frequency band, stations are subject to frequency coordination requirements with systems deployed in the US under the following conditions:

  • Stations within 56 kilometres (35 miles) of the border and where the antenna’s main beam direction overlaps the 200° sector towards the border (the 200° sector towards the border is centered on the shortest line pointing directly towards the border)
  • Stations within 8 kilometres (5 miles) of the border and where the antenna’s main beam direction is included in the 160° sector away from the Canada-United States border (the 160° sector away from the border is centered on the line pointing in the opposite direction of the shortest line pointing directly towards the border)