SRSP-508 — Technical Requirements for Digital Cordless Telephone (DCT) Systems Operating in the Band 944-948.5 MHz

Technical Requirements for Digital Cordless Telephone (DCT) Systems Operating in the Band 944 - 948.5 MHz
(PDF, 117 KB, 11 pages)

Issue 2
Effective Date: January 23, 1993

Spectrum Management
Standard Radio System Plan

TABLE OF CONTENTS

  1. Intent
  2. General
  3. Related Documents
  4. Band Plan
  5. Dynamic Channel Allocation Strategy for CSCs
  6. Dynamic Channel Allocation Strategy for Traffic Channels
  7. Technical Considerations

1. Intent

1.1 This Standard Radio System Plan (SRSP) states the minimum technical requirements essential for the purpose of efficient spectrum utilization to operate Digital Cordless Telephone (DCT) systems according to the CT2Plus Class 2, common air interface (CAI), in the band 944-948.5 MHz.

2. General

2.1 This Standard is intended to be employed in the design and specification of radio systems and equipment and in the evaluation of technical applications for new radio facilities or of modifications to existing radio facilities submitted in accordance with the current issue of Radio Standards Procedure (RSP) 101.

2.2 This Standard specifies equipment characteristics relating to efficient spectrum usage only and is not to be regarded as a comprehensive specification for equipment design and/or selection.

2.3 Revision of this Standard will be made as required.

2.4 Although a radio system conforms with the requirements of this SRSP, the Department may require modifications to the system whenever harmful interference1 is caused to other radio sites or systems.

2.5 When potential conflicts between systems cannot be resolved, the Department shall be so advised; whereupon after consultations with the parties concerned, it will determine the necessary modifications and/or schedule of modifications.

2.6 Equipment used for Digital Cordless Telephone (DCT) operating in the band 944-948.5 MHz must comply with appropriate Technical Standards listed in section 3.1.

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

2.8 The arrangements for non-standard systems are outlined in SP-GEN, "General Information Related to Spectrum Utilization and Radio System Policies".

2.9 The following definitions are applicable for the purpose of this document (see Fig. 1):

2.9.1 The CT2Plus Class 2 system: A second generation cordless telephone system with enhanced protocols, which employs Time Division Duplex (TDD) transmission with an instantaneous data rate of 72 kbps, based on Frequency Division Multiple Access (FDMA) technology. The carrier spacing is 100 kHz and the transmitter centre frequency must be within ±10 kHz of the channel frequency. The modulation is binary Frequency Shift Keying (FSK) with a modulation index between 0.4 and 0.7 corresponding to a peak frequency deviation between 14.4 and 25.2 kHz.

2.9.2 Cordless Portable Part (CPP): A portable piece of Cordless Telephone Apparatus (CTA) which, by integral radio and antenna means and in conjunction with a Cordless Fixed Part (CFP) and Common Control Fixed Part (CCFP), permits the functions of voice or data communications apparatus.

2.9.3 Cordless Fixed Part (CFP): A functional configuration of some components of a Common Control Fixed Part (CCFP) along with one or more Radio Fixed Parts (RFPs), each RFP being able to provide a radio signal to points in the coverage area with substantially the same signal strength as any of the other RFPs.

2.9.4 Cordless Telephone Apparatus (CTA): In this document, CTA refers to components and to a collection of components that comprise a digital cordless telephone system which are to be tested, or are undergoing testing. The meaning will be obvious from its context.

2.9.5 Radio Fixed Part (RFP): A fixed piece of CTA that interfaces between the CCFP and an antenna system for one duplex communication channel.

2.9.6 Common Control Fixed Part (CCFP): A fixed piece of CTA which provides the common controlling functions for one or more CFPs.

Figure 1: Component parts of CTA

Figure 1: Component parts of CTA

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3. Related Documents

The current issues of the following documents are applicable:

3.1 Reference Documents

3.1.1 Radio Standards Procedure (RSP) 100: Certification of Radio Equipment.

3.1.2 Radio Standards Procedure (RSP) 101: Application Procedure for Planned Radio Stations Operating on Frequencies Below 960 MHz.

3.1.3 Radio Standards Specification (RSS) 130: Digital Cordless Telephones in the Band 944 to 948.5 MHz.

3.1.4 Annex 1 to RSS-130: CT2Plus Class 2: Specification for the Canadian Common Air Interface for Digital Cordless Telephony, Including Public Access Services.

3.1.5 Spectrum Utilization Policy (SP)  896 MHz: Spectrum Utilization Policy for the Fixed, Mobile, Radiolocation and Amateur Services in the Band 896-960 MHz.

3.1.6 Spectrum Utilization Policy (SP)-GEN: General Information Related to Spectrum Utilization and Radio System Policies.

3.1.7 A Digital Cordless Telephone Service in Canada, DOC, May 1992.

3.2 Information Documents

3.2.1 Specification of the Audio Requirements for CT2Plus Class 2 Digital Cordless Telephones in Canada, DOC January 1993.

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4. Band Plan

4.1 Channelling Plan

The channelling plan as outlined in Tables 1 and 2 below is based on 100 kHz channel separation. The forty (40) channels listed in Table 1 are assigned for traffic channels. The five (5) channels listed in Table 2 are reserved for Common Signalling Channels (CSCs).

TABLE 1: CARRIER FREQUENCIES (MHz) FOR DIGITAL CORDLESS TELEPHONE RADIO TRAFFIC CHANNELS (MHz)
1. 944.0500 11. 945.0500 21. 946.0500 31. 947.0500
2. 944.1500 12. 945.1500 22. 946.1500 32. 947.1500
3. 944.2500 13. 945.2500 23. 946.2500 33. 947.2500
4. 944.3500 14. 945.3500 24. 946.3500 34. 947.3500
5. 944.4500 15. 945.4500 25. 946.4500 35. 947.4500
6. 944.5500 16. 945.5500 26. 946.5500 36. 947.5500
7. 944.6500 17. 945.6500 27. 946.6500 37. 947.6500
8. 944.7500 18. 945.7500 28. 946.7500 38. 947.7500
9. 944.8500 19. 945.8500 29. 946.8500 39. 947.8500
10. 944.9500 20. 945.9500 30. 946.9500 40. 947.9500

 

TABLE 2: CARRIER FREQUENCIES (MHz) FOR COMMON SIGNALLING CHANNELS (CSCs)
41. 948.0500
42. 948.1500
43. 948.2500
44. 948.3500
45. 948.4500

4.2 Common Signalling Channels (CSCs)

Details regarding the use of the CSCs are found in clause 5 of reference 3.1.4.

Briefly, each of the radio frequencies reserved for CSC use supports 12 CSCs. A given CFP normally uses only one CSC. Up to 12 CSCs from different CFPs can share a given carrier frequency using a superframe structure (see Fig. 2). On each CSC, three bursts are alternately transmitted and received each superframe. Thus, the transmission coming from a given CFP is three 1 ms bursts, with 1 ms receive slots adjacent to them, followed by a 66 ms gap until the next superframe. On a given CSC, the first burst is transmitted by the CFP (outbound). This first burst starts 72 ms after the start of the first outbound burst of the previous superframe. The second and third outbound bursts on a given superframe start 2 ms and 4 ms respectively after the start of the first outbound burst on that superframe. When CPP transmissions are present on a CSC, each burst transmitted by the CPP shall follow 5.5 ± 0.25 bit periods after the end of the preceding outbound burst from the CFP. When transmitting on a CSC, the CPP synchronizes its timing to the CFP, which is the master.

Figure 2: Multiplex frame structure on CSCs (Multiplex 4)

Figure 2: Multiplex frame structure on CSCs (Multiplex 4)

4.3 Traffic Channels

Details regarding the use of traffic channels are found in reference 3.1.4.

Briefly, each of the radio frequencies assigned for traffic channels supports one full duplex link. Each link consists of a 32 kb/s B channel for voice or data bits, and a 1 or 2 kb/s D channel for signalling.

4.4 CTA Access to Channels

The CPP shall have access to all frequencies assigned for traffic channels listed in Table 1 and to all frequencies reserved for CSCs listed in Table 2.

The CFP shall have access to all frequencies assigned for traffic channels listed in Table 1. The CFP, if it has Class 2 capability (see reference 3.1.3), shall also have access to all frequencies reserved for CSCs listed in Table 2.

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5. Dynamic Channel Allocation Strategy for CSCs

The CSC used by a given CFP is selected using dynamic channel allocation; i.e. each CFP is entitled to use any CSC from Table 2 which is determined by the CFP to be free.

Briefly, a free CSC is defined as the following:

  1. Any CSC with a local field strength below an absolute maximum of 40 dBμV/m; or
  2. where all CSCs that the CFP is capable of accessing are above 40 dBμV/m, then any CSC which has the lowest field strength of all CSCs as measured to a nominal resolution of 6 dB or better,

but may exclude any CSC on which interference is known to exist.

Further details are found in subclause 5.2.3.1 of reference 3.1.4.

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6. Dynamic Channel Allocation Strategy for Traffic Channels

6.1 Channel Selection

The traffic channel used by a given CPP or CFP for a call is selected using dynamic channel allocation; i.e. each CFP or CPP is entitled to use any traffic channel from Table 1 which is determined to be free.

Briefly, for equipment with Class 2 capability (see reference 3.1.3) a free traffic channel is defined as the following:

  1. any traffic channel other than channel 40 with a local field strength below an absolute maximum of 40 dBμV/m; or
  2. where all traffic channels, other than channel 40, are above 40 dBμV/m, then any traffic channel, including channel 40, which has the lowest field strength of all traffic channels listed in Table 1 as measured, by intermittent or continuous monitoring, to a nominal resolution of 6 dB or better.

but may exclude any channels on which unsuccessful attempts have been made to establish communications.

Further details are found in subclause 5.2.3.2 of reference 3.1.4.

Briefly, for CFPs without Class 2 capability (see reference 3.1.3) a free traffic channel is defined as the following:

  1. any traffic channel with a local field strength below an absolute maximum of 40 dBμV/m; or
  2. where all traffic channels are above 40 dBμV/m, then any traffic channel which has the lowest field strength of all traffic channels listed in Table 1 as measured, by intermittent or continuous monitoring, to a nominal resolution of 6 dB or better.

but may exclude any channels on which unsuccessful attempts have been made to establish communications.

Further details are found in subclause 4.4 of Attachment 1 of reference 3.1.4.

6.2 Termination of the Communication State

RF activity on a traffic channel is required to cease when action is taken to terminate the communication state between CPP and CFP. Further details are found in subclause 4.8 of Attachment 1 of reference 3.1.4.

RF activity on a traffic channel shall cease if RF link conditions are such that more than 10 s has elapsed without any successful handshake (see subclause 5.5 of Attachment 1 of reference 3.1.4).

6.3 In-Communication Channel Switching

The traffic channel used for a link between a CPP and a CFP may be changed during the link. Rules and procedures regarding in-communication channel switching are found in reference 3.1.4.

6.4 Mobility Hand-off

During a link, the CFP used to communicate with a CPP may be permitted to be changed. Equipment permitted to support mobility hand-off is specified in reference  3.1.3. Rules and procedures regarding mobility hand-off are found in reference 3.1.4.

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7. Technical Considerations

7.1 Synchronization

Synchronization on traffic channels refers to arranging the transmissions from different CFPs on traffic channels to occur at the same time; i.e. arranging for the outbound 1 ms transmission slots on traffic channels to be time-aligned. Synchronization also refers to arranging the transmissions from different CFPs on CSCs to be aligned to the same superframe; i.e., arranging for the three outbound 1 ms transmission slots on CSCs to be time-aligned to the same superframe. Synchronization minimizes RF interference because when synchronized, CFPs do not interfere with each other and the CPPs in communication with them do not interfere with each other.

All public service providers are recommended to conform to the following synchronization guidelines:

7.1.1 When synchronization should be implemented

  • Synchronization is recommended for systems operating with overlapping cells.
  • Synchronization is highly recommended for CTAs operating in overlapping coverage areas and with a separation path loss of 60 dB or less in order to reduce the level of interference and minimize the reduction in system traffic capacity.

    Note: If a CFP uses a directional antenna, then the 60 dB path loss should be adjusted by the appropriate antenna gains.

  • Synchronization need not be implemented in the case of non-overlapping cells.
  • Synchronization need not be implemented for CTAs with 2 or less RFPs.
  • Synchronization of CFPs within the same CTA is recommended in the case of overlapping coverage.

7.1.2 How synchronization should be done

  • The first CTA with digital trunks should be designated the master system and should provide synchronization data to other systems at the same serving area.
  • Each CTA system conforming to the synchronization guidelines should be equipped with a synchronization electrical interface. This interface permits the transport of synchronization data over a balanced pair of wires (twisted pair).
  • The interface should be equipped with a synchronization input port to receive synchronization data from other systems.
  • Other synchronization transport mechanisms may be used if approved and agreed by the synchronization parties. The standard electrical interface should always be available as a minimum.
  • Synchronization should include synchronization of the TDD bursts and also the CSC slots.

7.2 Effective Radiated Power (ERP)

  1. The maximum ERP per channel delivered over an RF cycle shall be limited to 10 mW (17 mW EIRP) for CTAs with up to two RFPs (with either external or integral antennas).
  2. The maximum ERP from integral antennas shall be limited to 10 mW per channel delivered over an RF cycle (17 mW EIRP) for CTAs with three or more RFPs.
  3. The maximum ERP per channel delivered over an RF cycle from external antennas shall be limited to 30 mW (50 mW EIRP) for CTAs with three or more RFPs, but the total power radiated by the antenna systems connected to each CFP shall be limited to 10 mW per channel delivered over an RF cycle.

    Note: Directional antennas are expected to be used primarily in outdoor applications.

  4. For distributed antenna systems connected to each CFP that would radiate total power in excess of 10 mW per channel delivered over an RF cycle, licences may be granted as non-standard systems on a case-by-case basis in accordance with the Department policy specified in SP-GEN.

    Note: Where equipment is capable of delivering more than 10 mW to offset cable loss, care should be taken that the power into the antenna does not exceed 10 mW.

7.3 RF Power Control

CPPs and CFPs may switch their output power between two settings: normal power and low power. Briefly, low power is 16 dB below normal power. Details regarding RF power control are found in subclause 5.2.4 of reference 3.1.4 and subclause 4.5 of Attachment 1 of reference 3.1.4.

7.4 Co-Existence with other Radio Systems

It should be noted that line-of-sight radio systems in the fixed service operate in the band 942.5-944 MHz in accordance with SRSP-507. Further, the band 944-948 MHz is used for studio-transmitter link (STL) in the United States.

For any information concerning assignments to these systems, appropriate DOC District offices may be contacted.

7.5 Public Access to Emergency Service

Subclause 5.4.5 of reference 3.1.4 and subclause 6.4.5 of Attachment 1 of reference 3.1.4 specify that public access CFPs shall connect any CPP to the default emergency service, if the CPP sets up a call using a special emergency code. It is the responsibility of the public access provider to determine what the default emergency service shall be.

7.6 Equipment Certification

All radio equipment will be certified under provisions of Radio Standards Specification (RSS) 130.

7.7 Licensing Considerations

With regard to licence exempt systems as per Section VI b. of reference 3.1.7, the provisions of Section 6 of Part II of General Radio Regulations made pursuant to the Radiocommunication Act apply. Such licence exempt systems cannot claim protection from or cause interference to the licensed users.

Issued under the authority of
the Minister of Communications

S.N. Ahmed
Director General
Engineering Programs Branch

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Footnotes

1 For the purpose of this SRSP, harmful interference means interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with regulations and technical requirements laid down by the Minister of Communications under the Radiocommunication Act.

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