1、CEPT T/R*K24-04E 88 = 2326434 0006787 7 Page E 1 Recommendation T/R 24-04 (Edinburgh 1988) RADIOCHARACTERISTICS OF SHORT RANGE RADIO (SRR) IN THE 900 MHi-BAND USING DIGITAL TECHNIQUES Recommendation proposed by Working Group T/WG 16 “Radio Equipment and Systems” (RES) Text of the Recommendation adop
2、ted by the “Telecorrzmunicatioris” Commission: “The European Conference of Postal and Telecommunications Administrations, considering (a) that modern technology allows low-power radio transmitter-receiver (transceiver) and multi-channel trunking mode in the 900 MHz band for Short Range Radiocommunic
3、ation between mobile and base stations or between mobile stations using digital modulation for the transmission and reception of voice and data at a gross bit rate of 16 kbit/s, (b) that this technology can improve frequency economy, (c) that this technology can largely avoid interference by using o
4、nly free channels, (d) that such equipment can solve problems of Administrations, in meeting the demand for short range radio- communications, for instance in urban areas, (e) that it is desirable for CEPT Administrations to have common regulations and technical specifications, (f) that frequency co
5、ordination between Administrations, intending to introduce Short Range Radio (SRR) will be eased, thanks to the principles of the system, (g) that common regulations and technical specifications will ease border crossing and facilitate the temporary use of Short Range Radio equipment in foreign coun
6、tries, (h) that Short Range Radio may be accomplished both in a single frequency simplex mode and in a two frequency semi duplex mode, which can coexist, (i) that Administrations may adopt either the single frequency simplex mode system or the two frequency semi duplex mode system, or both, recommen
7、ds 1. that, as far as national regulations permit, the members of the CEPT should permit the use of SRR equipment in the non-public Land Mobile Service under the technical conditions in the Annexes, 2. that for the type approval tests the methods of measurement described in the relevant sections of
8、the present Recommendation should be used, 3. that the test reports should be in conformity with CEPT Recommendation T/R 71-02 E, 4. that, in drawing up test reports, the Administrations should as far as possible follow the order of the tests and numbering of the paragraphs used in the Annexes and a
9、dopt the nomenclatures in the Annexes of this Recom- mend at i on , 5. that CEPT members should ailow on a bilateral basis the border crossing and the temporary use of SRR equipment, which has been type-approved and is marked in accordance with the relevant Annex, 6. that the technical characteristi
10、cs of SRR equipment operating in a single frequency simplex mode or two frequency semi duplex mode mentioned in the present Recommendations, should be used for the development of equipment, 7. that CEPT members shall evaluate the technical characteristics given in Annexes A and B at an appropriate t
11、ime when the necessary development of equipment has taken place.” Edition of September 15, 1988 TIR 24-04 E Page 2 Contents ANNEX A . GENERAL SPECIFICATIONS Page 1 . 2 . 2.1. 2.2. 3 . 4 . 5 . 6 . 7 . 8 . 9 . 10 . 11 . 12 . 13 . 14 . 15 . 16 . DESCRIPTION 1 DESCRIPTION OF THE PRINCIPLES OF OPERATION
12、1 Single Frequency Simplex Working 1 Two Frequency Semi Duplex Working . 4 FREQUENCY BAND FOR SRR EQUIPMENT 7 CARRIER FREQUENCIES AND CHANNEL NUMBERS . 7 CONTROL CHANNEL(S) . 7 CHAML SEPARATION 7 MODE OF OPERATION . 8 MODULATION. . 8 SYNTHESISERS AND PLL SYSTEMS . 8 TIME LIMITATION ON CHANNEL OCCUPA
13、NCY . 8 THRESHOLD LEVEL FOR RF SENSING AND MINIMUM OBSERVATION TIME 8 THE SELECTIVE SIGNALLING CODE . 8 THE CODING SYSTEM 9 TYPE-APPROVAL MARK . 9 MECHANICAL AND ELECTRICAL DESIGN 9 RF SPECIFICATION SUMMARY . 10 ANNEX B . TECHNICAL SPECIFICATIONS 1 . 1.1. 1.2. 1.3. 1.4. 2 . 2.1. 2.2. 2.3. 2.4. 2.5.
14、2.6. 2.7. 2.8. 3 . 3.1. 3.2. 3.3. 3.4. 3.5. 3.6. 3.7. 3.8. 3.9. 4 . GENERAL 1 External Antenna 1 Test Conditions. Power Sources. and Ambient Temperatures . 1 General Conditions . 2 Test Site and General Arrangements for Measurements Involving the Use of Radiated Fields 3 TRANSMITTER 5 Carrier Power
15、. 5 Adjacent Channel Power . 6 Spurious Emissions . 9 Intermodulation Attenuation . 9 Transmitter Attack Time 10 Transmitter Release Time 11 Transmitter Transient Behaviour 11 RECEIVER 15 Maximum Usable Sensitivity . 15 Bit Error Rate . 15 Co-Channel Rejection 15 Adjacent Channel Selectivity . 16 Sp
16、urious Response Rejection . 17 Intermodulation Response 17 Blocking or Desensitisation 18 Spurious Emissions . 18 Receiver Opening Delay . 19 ACCURACY OF MEASUREMENT . 19 . Frequency Error 5 Appendices 1 . Calculation of First Operating Channel 2 . Attribution of Numbers and Abbreviations of Countri
17、es 3 . Control Channel Retries 4 . Calculation of Channel Number 5 . Flow diagram single frequency simplex mode working and call set up timing 6 . Flow diagram two frequency semi duplex mode working and call set up timing Edition of September 15. 1988 CEPT T/R*K24-04E 88 2326434 O006789 O TIR 24-04
18、E Annex A, Page 1 ANNEX A. GENERAL SPECIFICATIONS 1. DESCRIPTION 1.1. General A Short Range Radio (SRR) is a low power radio transmitter-receiver (transceiver) of the non-public land mobile service intended to provide Short Range Radiocommunications using voice or data in the single frequency simple
19、x mode in the frequency band 933-935 MHz or in the two frequency semi duplex mode in the frequency bands 933-935 MHz, paired with 888-890 MHz. Direct digital modulation of the carrier is used to send the selective signalling code and voice and/or data messages. SRR is equipment with: - an automated
20、multichannel access technique without the assistance of a central controller, and - a reprogrammable read only memory facility (see Clause 15.). SRR uses a selective signalling code which is described in Clause 12. ; a part of the selective signalling code may be prescribed by the licence authority
21、in order to uniquely identify the equipment and hence the licencee. Operation of SRR should only be possible when the reprogrammable read only memory facility is correctly programmed. 1.2. Single Frequency Working When the single frequency mode is used, two way communication is possible from hand po
22、rtable to hand portable stations, portable to vehicle mobile stations, mobile to mobile stations, portable to base stations and vehicle mobile to base stations, as required by the user. All single frequency stations operate in the simplex mode. In the standby mode, all stations are receiving on one
23、or other of the control channels. 1.3. Two Frequency Working When the two frequency mode is used, two way communication is possible between the base station and hand portable or vehicle mounted mobile stations. When the two frequency mode is used, a base station may also be used as a repeater statio
24、n to allow portable to portable, portable to mobile and mobile to mobile station two way communication over increased ranges compared to those achieved with single frequency working. To permit other base stations to monitor the use of a trafic channel, all two frequency base stations, whether in the
25、 repeater mode or base station mode, operate in the full duplex mode with continuous transmission and reception on the traffic channel, while it is in use. In order to enable monitoring of the traffic channels to permit selection of a free traffic channel, all two frequency base stations are to be c
26、apable of receiving either on base station transmitting frequencies or on mobile station transmitting frequencies, but not both at once. In the standby mode a two frequency base OS repeater station is receiving on one of the control channels. When searching for a free traffic channel a two frequency
27、 base or repeater station is scanning the base station transmitter frequencies. When operating on the selected trafic channel a two frequency base or repeater station is receiving on the selected traffic channel mobile transmit frequency. 2. PRINCIPLES OF OPERATION 2.1. Single Frequency Simplex Work
28、ing 2.1.1. The system provision The system makes use of 2 control channels to administer 75 traffic channels for voice and or data two way communication. Channels 02 and 78 are not used being reserved for additional control channels for two frequency operation. Edition of September 15, 1988 1 -, -_.
29、I_ CEPT T/R*Z4-04E 88 m 232b414 0006790 7 m T/R 24-04 E Annex A, Page 2 2.1.2. The selective signalling code The selective signalling code is designed to set up an appropriate two way communication channel, so that communication by voice or data may follow. The selective signalling code also identif
30、ies the station originating the call and contains the identity of the station or stations being called. The composition of the signalling code is described in Clause 12. In order to set up the two way communication channel, the station initiating the call has to locate a free channel. The station in
31、itiating the call can be a mobile or a base station. The equipment is designed to operate on two designated control channels. In the standby mode a station is normally receiving on the first control channel. It changes to and receives on the second control channel if spurious signals are present on
32、the first one for more than 5 seconds. After receiving on the second control channel for 5 seconds, it switches back automatically to the first control channel. If spurious signals are still present on the first control channel the procedure is repeated, indefinitely if necessary. A spurious signal
33、is any signal above the threshold level of maximum usable sensitivity which is not recognised as control channel data. To initiate a call, the operator selects the unique calling code of the wanted mobile or base station and activates the call function. The station initiating the call then scans onc
34、e the allocated channels to find a free channel and stores that channel number in its memory. It then returns to the first control channel and monitors the control channel to ensure it is free. If the control channel is free it then transmits the full selective signalling code comprising the address
35、 code of the wanted station, the free channel number previously located, a command code used to indicate any special mode of operation, the address code of the call initiating station and its nationality code. However, if the control channel is already in use at that time, then the calling station m
36、ust wait either: i) to the end of an acknowledgement code word (identified by bit No. 1 being “O” in each part of the address code words), or ii) at least 200 ms after the end of a selective signalling code word, to allow i) to take place should the called station be in range and available. The sele
37、ctive signalling code words are transmitted in 160 ms. The 200 ms wait therefore allows for 40 ms Rx to Tx switching time. To minimise delay in finding a free channel each station will scan for a free channel in accordance with Appendix 1. After the transmission of the full selective signalling code
38、 word, the calling station then switches to receive on the control channel and waits for 200 ms for an acknowledgement code word from the wanted station. If an acknowledgement code word is received, both stations switch to the already identified trafic channel and monitor it for 200 ms to ensure the
39、 identified trafic channel is free, at which point the calling station sends the full selective signalling code and waits again for 200 ms for a further acknowledgement code word from the wanted station. If received, the call ready indicator on the calling station operates. The call ready indicator
40、on the wanted station operates on the first press to talk transmission by the calling station. The call ready indicator may be an audible or visual indication or both. If no further acknowledgement code word on the traffic channel from the wanted station is received, the calling station returns to t
41、he standby mode on the calling channel. Similarly the called station will return to standby on the control channel after 500 ms if it does not receive the selective signalling code word from the calling station on the trafic channel. In the event of a further attempt by the operator of the calling s
42、tation to call the same wanted station, the calling station when scanning for a free channel will commence at the previously chosen trafic channel plus one. This is to minimise the chance of selecting the same traffic channel, which was not suitable, a second time. If an acknowledgement code word fr
43、om the called station is not received on the control channel, the following procedures are implemented. 2.1.3. Setting up a call 2.1.4. Initiating an individual call 2.1.5. Absence of acknowledgement Edition of September 15, 1988 CEPT T/R*24-04E 88 = 2326434 000b791 9 2.1.6. 2.1.7. 2.1.8. 2.1.9. 2.1
44、.10. TIR 24-04 E Annex A, Page 3 At time intervals the calling station repeats automatically, in accordance with Appendix 3, the full selective signalling code whilst still on the rst control channel. It switches to receive after each transmission for 200 ms to monitor for an acknowledgement code wo
45、rd from the wanted station. As soon as an acknowledge- ment code word is received, the sequence of events described in 2.1.4. is followed. If after the total of three attempts by the calling station no acknowledgement code word is received from the wanted station, the calling station repeats the pro
46、cedures outlined above on the second control channel. The selection of the second control channel is timed out in five seconds for reversion to the first control channel. The channel scanning cycle In order to complete the channel scanning cycle as rapidly as possible, the station dwells on an occup
47、ied channel for not more than 50 ms. When an apparently unoccupied channel is located, the dwell time increases to 1 .O second to ensure that any use of the channel is identified. Only when a channel is unoccupied for 1.0 second is it identified as a free channel. As described above, the stations wh
48、ich will have switched to the originally identified free channel are inhibited from transmitting until the channel has been monitored again, either to be free for 200 ms, or until the full selective signalling code which includes their address code is received. Detection of any other address code or
49、 other signals above the threshold level causes the stations to switch back to the first control channel and the call ready indicators will not operate. Identjcation for monitoring purposes The full selective signalling code word is transmitted automatically at the beginning of each transmission on the traffic channel. Limitation of congestion on traffic channels To limit congestion on the system each station is fitted with a time-out timer to limit the communication period. The timer prevents any one way voice or data transmission exceeding a duration of one minute
