APT · Web view3.2.1 Deployment of Digital Train Radio System (Digital TRS)7 3.2.2 Deployment of...

APT REPORT ON SYSTEM DEPLOYMENT AND RELEVANT TESTING STUDIES OF

RAILWAY RADIOCOMMUNICATION SYSTEM BETWEEN TRAIN AND TRACKSIDE (RSTT) IN APT COUNTRIES

No. APT/AWG/REP-94Edition: July 2019

Adopted by

25th Meeting of APT Wireless Group1 – 5 July 2019, Tangerang, Indonesia

(Source: AWG-25/OUT-17)

APT/AWG/REP-94

APT REPORT ON SYSTEM DEPLOYMENT AND RELEVANT TESTING STUDIES OF RAILWAY

RADIOCOMMUNICATION SYSTEM BETWEEN TRAIN AND TRACKSIDE (RSTT) IN APT COUNTRIES

TABLE OF CONTENT1. SCOPE.................................................................................................................................................3

2. BACKGROUND.................................................................................................................................3

3. RSTT DEPLOYMENT IN APT COUNTRIES...............................................................................3

3.1 RSTT DEPLOYMENT IN CHINA .........................................................................................................33.1.1 Deployment of GSM-R in China.................................................................................................3

3.1.1.1 Wireless Networking............................................................................................................33.1.1.2 GSM-R deployment in different scenarios..........................................................................4

3.1.1.2.1 Railway line..................................................................................................................43.1.1.2.2 Railway station.............................................................................................................73.1.1.2.3 Shunting yard................................................................................................................73.1.1.2.4 Maintenance Base.........................................................................................................7

3.2 RSTT DEPLOYMENT IN JAPAN .........................................................................................................73.2.1 Deployment of Digital Train Radio System (Digital TRS).........................................................73.2.2 Deployment of Digital Radio communication system for High Speed Trains (Digital RHST)..83.2.3 Deployment scenarios of future 100 GHz RSTT........................................................................9

3.3 RSTT DEPLOYMENT IN KOREA ......................................................................................................123.3.1 Deployment of LTE-R systems.................................................................................................12

3.3.1.1 Service overview of LTE-R system...................................................................................123.3.1.2 System Characeeristics ......................................................................................................133.3.1.3 Deployment of LTE-R.......................................................................................................133.3.1.4 Basic structure of LTE-R...................................................................................................143.3.1.5 Design Principle of LTE-based railway communication system (LTE-R) ........................153.3.1.6 LTE based Railway Communication System Architecture ...............................................153.3.1.7 LTE-R network in METRO...............................................................................................17

3.3.2 Deployment of Other communication systems.........................................................................17

4. RSTT FIELD TESTING STUDIES IN APT COUNTRIES.........................................................20

4.1 RSTT FIELD TESTING STUDY IN CHINA ..........................................................................................204.1.1 GSM-R field testing study in China..........................................................................................20

4.1.1.1 GSM-R Radio Field Coverage Test...................................................................................204.1.1.2 GSM-R QoS Test...............................................................................................................21

4.2 RSTT FIELD TESTING STUDY IN JAPAN ..........................................................................................224.2.1 Digital Train Radio System (Digital TRS) field testing study..................................................224.2.2 Digital Radiocommunication system for High Speed Trains (Digital RHST) field testing study ............................................................................................................................................................224.2.3 100 GHz RSTT field testing study............................................................................................23

4.2.3.1 100 GHz RSTT Transceiver characteristics.......................................................................234.2.3.2 Filed test in Hokuriku Shinkansen.....................................................................................27

4.3 RSTT FIELD TESTING STUDY IN KOREA .........................................................................................284.3 .1 LTE-R verification test ..............................................................................................................284.3.2 Wonju-Pyungchang field test....................................................................................................304.3.3 LTE-R field testing ....................................................................................................................31

of 42

APT/AWG/REP-94

4.3.3.1 LTE-R Radio field Coverage test.......................................................................................32

5. STUDIES ON RADIO PROPAGATION CHARACTERISTICS UNDER HIGH SPEED MOVEMENT IN TYPICAL SCENARIOS............................................................................................33

5.1 RELEVANT RADIO PROPAGATION STUDY IN CHINA ........................................................................335.1.1 Propagation scenarios................................................................................................................345.1.2 Analysis results..........................................................................................................................355.1.3 Conclusion.................................................................................................................................37

5.2 RELEVANT RADIO PROPAGATION STUDY IN JAPAN ........................................................................375.2.1 LCX propagation study .............................................................................................................375.2.2 100 GHz propagation study .......................................................................................................38

6 LIST OF ACRONYMS AND ABBREVIATIONS.........................................................................38

7 REFERENCE...................................................................................................................................39

of 42

APT/AWG/REP-94

1. Scope

This APT Report, based on contributions from some APT members, provides relevant deployment information on existing RSTT, studies on proposed deployment of certain future RSTT, relevant field testing studies related to the deployment of RSTT, and also provides study results in radio propagation characteristics under high speed movement in typical scenarios.

2. Background

In order to share experiences of deployment of railway radiocommunication systems, and to share studies on radio propagation characteristics under high speed movement in typical scenarios and other field testing studies which are related to deployment of RSTT, APT Members agreed to initiate this study, for providing administrations and railway operators in Asia-Pacific region with relevant information on experiences and supplemental studies of RSTT deployment.

3. RSTT deployment in APT countries

3.1 RSTT Deployment in China

3.1.1 Deployment of GSM-R in China

GSM-R, Global System for Mobile Communications – Railway, is an international wireless communications standard for railway communication and applications. In China, GSM-R system (operating in 800/900 MHz band) has been deployed over 48,000 kilometers lines by the end of 2017, including part of existing regular lines and all high-speed lines.

3.1.1.1 Wireless Networking

According to different application requirements, there are three methods usually used to set up BTSs along railway line in China: single network coverage, single network intertwined coverage, co-located double network coverage.

Single network coverage

Single network coverage is the most frequently used network coverage method in wireless telecommunication networks. In this method, base stations are set up according to the coverage of each base station. The coverage of adjacent base stations usually overlaps with each other to ensure handover between base stations. Single network coverage is shown in Figure 1:

Figure 1 Network Architecture of Single Network Coverage

Single network intertwined coverage

of 42

APT/AWG/REP-94

Single network intertwined coverage means single network is used to cover the railway line, and each base station can cover the area belong to adjacent base stations. GSM-R network is still usable when non-continuous base station is down by using this wireless networking method. Single network intertwined coverage is shown in Figure 2:

Figure 2 Network Architecture of Single Network Intertwined Coverage

Co-sited double network coverage

Co-sited double network coverage means double network are used to cover the railway line, one network is a master network while the other one is a backup network. Two independent base stations connecting to different BSCs are set up at one site. Mobile stations will connect to the master network in preference. When master network is down, mobile stations will connect to standby network. Co-sited double network coverage is shown in Figure 3

Figure 3 Network Architecture of Co-Sited Double Network Coverage

3.1.1.2 GSM-R deployment in different scenarios

3.1.1.2.1 Railway line

In this report, the Hangzhou-Changsha passenger dedicated line and the Baoji-Lanzhou passenger dedicated line are chosen to describe the GSM-R network deployment along railway lines.

Hangzhou-Changsha passenger dedicated line connects the city of Hangzhou in Zhejiang Province and the city of Changsha in Hu’nan Province. The designed operational speed of this line is 350 km/h. Single network intertwined coverage is used in this line.

Baoji-Lanzhou passenger dedicated line connects the city of Baoji and the city of Lanzhou in Gansu Province. The designed operational speed of this line is 250 km/h. Single network coverage is used in this line.

of 42

APT/AWG/REP-94

Viaducts (single network coverage)

One part of the long viaduct in Baoji-Lanzhou Line is chosen to describe the deployment of GSM-R network along viaducts using single network coverage. Network architecture is shown in Figure 4:

Figure 4 Network Architecture of Viaduct in Baoji-Lanzhou Line

In Figure 4, traditional base stations and antennas are used to cover viaducts. For example, BTS-1, BTS-2, BTS-3, BTS-4 are used to cover the railway line, where the distances between the stations are 4508m (BTS-1 to BTS-2), 4551m (BTS-2 to BTS-3) and 4047m (BTS-3 to BTS-4).

The sensitivity of base stations is better than -110dBm, and output power of the base stations is above 47dBm, and adjustable.

The parameters of the antennas are listed in TABLE 1:

TABLE 1 Parameters of Antenna

Parameter Value

frequency 870~960MHz

polarization +45°,-45°

gain ≥17dBi

front-back ratio ＞30dB

isolation ＞30dB

impedance 50Ω

VSWR ＜1.5

Viaducts (single network intertwined coverage)

One part of the long viaduct in Hangzhou-Changsha Line is chosen to describe the deployment of GSM-R network along viaducts using single network intertwined coverage. Network architecture is shown in Figure 5.

Figure 5 Network Architecture of Viaduct in Hangzhou-Changsha Line

In Figure 5, traditional base stations and antennas are used to cover viaducts. For example, BTS-

of 42

APT/AWG/REP-94

1, BTS-2, BTS-3, BTS-4 and BTS-5 are used to cover the railway line, where the distances between the stations are 3033m (BTS-1 to BTS-2), 2881m (BTS-2 to BTS-3), 2849m (BTS-3 to BTS-4) and 2897m (BTS-4 to BTS-5).

The sensitivity of base stations is better than -110dBm, and output power of the base stations is above 47dBm, and adjustable.

The parameters of the antennas are the same with TABLE 1.

Tunnel (single network coverage)

XINDIAN Tunnel is chosen to describe the deployment of GSM-R network in tunnels using single network coverage. Network architecture is shown in Figure 6:

Figure 6 Network Architecture of Tunnel in Baoji-Lanzhou Line

In Figure 6, repeaters and leaky cables are commonly used to cover railway line inside the tunnel; antennas are used to cover railway line between tunnels.

In the example mentioned above, railway line inside XINDIAN Tunnel is covered by 2 base stations and 3 repeaters and leaky cables connected to the BTSs. BTS-1 and BTS-2 are base stations. BTS-1/R1, BTS-2/R2 and BTS-2/R1 are repeaters. BTS-1/R1 is connected to BTS-1, and BTS-2/R2, BTS-2/R1 are connected to BTS-2. The distance between repeaters/base stations are 1800m (BTS-1 to BTS-1/R1), 1000m (BTS-1/R1 to BTS-2/R2), 1500m (BTS-2/R2 to BTS-2/R1) and 1764m (BTS-2/R1 to BTS-2).

The maximum output power of the repeaters is 30dBm, and input and output VSWR is lower than 1.4.

Tunnel (single network intertwined coverage)

ZAOJIAOPO Tunnel is chosen to describe the deployment of GSM-R network in tunnels using single network intertwined coverage. Network architecture is shown in Figure 7:

of 42

APT/AWG/REP-94

Figure 7 Network Architecture of Tunnel in Hangzhou-Changsha Line

In Figure 7, repeaters and leaky cables are commonly used to cover railway line inside the tunnel; antennas are used to cover railway line between tunnels.

In the example mentioned above, railway line inside ZAOJIAOPO Tunnel is covered by 4 repeaters and leaky cables connected to base station BTS-1 and BTS-2. BTS-1/R1，BTS-1/R2，BTS-1/R3 and BTS-1/R4 are repeaters. All 4 repeaters are connected to two different BTSs simultaneously. The distance between repeaters is 1490m (BTS-1 to BTS-1/R1), 690m (BTS-1/R1 to BTS-1/R2), 1000m (BTS-1/R2 to BTS-1/R3) and 925m (BTS-1/R3 to BTS-1/R4).

The maximum output power of the repeaters is 30dBm, and input and output VSWR is lower than 1.4.

3.1.1.2.2 Railway station

Generally, indoor and outdoor coverage of railway station could be achieved by specific GSM-R base station. According to different service requirements, each base station usually uses 2 to 4 carrier frequencies.

3.1.1.2.3 Shunting yard

GSM-R system is not deployed for shunting yards in China.

3.1.1.2.4 Maintenance Base

Generally, indoor and outdoor coverage of maintenance base is achieved by specific GSM-R base station. Each base station usually uses 2 carrier frequencies.

3.2 RSTT Deployment in Japan

3.2.1 Deployment of Digital Train Radio System (Digital TRS)

In Japan, Analog Train Radio Systems (Analog TRS), deployed for inter-city and inner-city, have been migrated to Digital TRS gradually, because of its increasing capacity of channels within the same frequency bandwidth. The channel separation for Analog TRS is 12.5 kHz or 20 kHz but it is 6.25 kHz for Digital TRS.

Network architecture of Digital TRS is shown in Figure 8. Base stations are set up along the track side with 2-3km interval and adjacent base station coverages are overlapped each other with minimum necessary range. So there is no area where radio communications are not available. Of-course in the case that a base station is down, radio communications in this coverage area is not available. But important units of those base stations are redundant; therefore, the possibility of the radio station down is very rare.

of 42

Note:f0: A frequency pair of downlink and uplink commonly used for all Radio Zones (Type1)f1-6: 3 frequency pairs of downlink and uplink for each Radio Zone (Type2) (According to the communication traffic, it is available to reduce frequency pairs from 3 to 2.) OCC: Operation Control CentreBS: Base Station

BS

OCC

2-3km

Radio Zone （ 20-30km ）

f0 f0 f0 f0f1,2,3 f1,2,3 f1,2,3 f1,2,3

BS

2-3km

f0 f0 f0 f0f4,5,6 f4,5,6 f4,5,6 f4,5,6


APT/AWG/REP-94

Operation Control Centre (OCC) accommodates some radio zones which usually correspond to respective railway lines. Dispatchers are assigned to each radio zone and responsible for their assigned zone.

Each radio zone has two types of frequency pair, type1 is for all radio zones and type2 is for each zone. Data streaming of all radio zones are the same on type1 and data streaming among each zone is the same on type2. While trains are at overlapping area, two incoming radios from adjacent stations are interfered each other and quality of communication go wrong in general. But advanced radio technology implemented to Digital-TRS, make it possible to realize high quality communication even where trains are at the overlapping area.

To reduce frequency bandwidth for this system, it is possible to repeatedly use the same type2 frequencies with deferent data streaming for each zone. But in this case, it is necessary to take some countermeasures against reducing interference at every radio zone boundaries for example dividing two zones by LCX. Network architecture of Digital TRS with same frequencies is shown in Figure 9.

Digital TRS is used in scenarios of Railway line and Railway Stations. Deployment methods of those different scenarios are same but in tunnel leaky cable is used.

Figure 8 Network Architecture of Digital TRS Network

of 42

Note:f0: A frequency pair of downlink and uplink commonly used for all Radio Zones (Type1)f1-3: 3 frequency pairs of downlink and uplink commonly used for each Radio Zone (Type2) (According to the communication traffic, it is available to reduce frequency pairs from 3 to 2.) OCC: Operation Control CentreBS: Base Station

BS

OCC

2-3km


f0 f0 f0 f0f1,2,3 f1,2,3 f1,2,3 f1,2,3

BS

2-3km

f0 f0 f0 f0


f1,2,3 f1,2,3 f1,2,3 f1,2,3

BS

20-30km

Repeater

f1 f2 f1 f2 f1 f2

BS BS

LCX

LCX

Repeater Repeater

Note:f1, f2: Two frequency pairs of downlink and uplink commonly used for all Radio ZonesBS: Base Station LCX: Leaky Coaxial cables

APT/AWG/REP-94

Figure 9 Network Architecture of Digital TRS with same frequencies

3.2.2 Deployment of Digital Radio communication system for High Speed Trains (Digital RHST)

In Japan, Leakey Coaxial Cable (LCX) based train radio is used for RHST. Deployment of digital RHST is shown in Figure 10.

Figure 10 Deployment of digital RHST

Base stations are set up at almost every railway stations which interval is about 40-60km. LCXs are laid at both side of the track and in order to compensate the propagation loss inside LCX, repeaters are set up with 1.4-1.5km interval along the track. Because of an influence of repeaters’ distortion and noise, maximum 25 repeaters are available for each Base Station; therefore coverage area of the base station is about 20-30km.

Two frequency pairs are commonly used for all radio zones and in case that a train move to other zone, it is possible to continue communications by handover.

While trains are at overlapping area, two incoming radios from adjacent stations with deferent data streaming are interfered each other and communications are impossible at zone sections. But those areas are too short that a pause during communication is under 1 second while trains are running. So communications are available in almost all the railway lines.

of 42

APT/AWG/REP-94

In the case that a base station or a repeater is down, radio communications in its coverage area are not available. But important units of stations and repeaters are redundant; the possibility of communication impossible is very rare.

Each radio zone has two pairs of frequencies those are also redundant at radio wave layer.

Digital RHST is used in scenarios of Railway line and Railway Stations. Deployment methods of those different scenarios are same.

3.2.3 Deployment scenarios of future 100 GHz RSTT

Japan is considering the 100 GHz band be studied for RSTT to address its importance for safety of railway systems. (For more information, please refer to APT/AWG/REP-78 APT Report on System Description, Technologies and Implementation of RSTT.) The possible basic system block diagram of this future 100GHz RSTT is shown in Figure 11, which consists of a number of trackside RAUs (Radio Access Units), node base stations and a central control station. The wireless links between trackside RAU and on-board units are operating in the frequency range 92-109.5 GHz which are already primary allocated for mobile services. The radio over fiber links connected trackside RAUs with node base stations. The node base stations provide radio signals to 10-20 trackside RAUs, depending on the distance between trackside RAUs and on-board units.

Figure 11 System blockdiagram of 100 GHz RSTT

Figure 12 shows the architectures of the in-vehicle and ground networks which can be named as communication-based train control and monitoring systems. The in-vehicle network consists of three functions shown below:

(1) Service information gathering and distribution

(2) Control information distribution to train vehicle equipment and devices

(3) Control information gathering from train vehicle equipment and devices, and monitoring information from CCTV

Those signals are transmitted to trackside RAUs through 100-GHz wireless links of on-board units on the train and then connected to the central control station via radio over fiber links in the ground network. The control and monitoring information gathering functions assist to develop the condition-based maintenance for high-speed railway systems.

of 42

APT/AWG/REP-94

Figure 12 Network architecture of communication-based train control and monitoring system for 100 GHz RSTT

Figure 13 shows the in-vehicle network which distributes control information to train vehicle equipment and devices in each car and gathers control and monitoring information from each car. The transmission unit in each car has DHCP (Dynamic Host Configuration Protocol) server function and IP addresses are allocated to all train vehicle equipment. All operational information of in-vehicle devices in each car can be displayed in driver’s room through the central unit to perform stable operation, management and maintenance of high-speed train systems. In addition to the display in the driver’s room, all information of in-vehicle devices stored in the maintenance unit can be transmitted to the ground network through 100-GHz wireless links, as described in the previous paragraph.

of 42

APT/AWG/REP-94

Figure 13 In-vehicle network of communication-based train control and monitoring system

The frequency arrangement of this system is shown in Figure 14 whose channel bandwidth is 400 MHz, and 4, 13 and 17 channels are assigned in the frequency band 92-94 GHz, 94.1-100 GHz and 102-109.5 GHz, respectively. The lower channels CH.1-CH.17 will be used for the links from trackside RAUs to on-board units and the upper channels CH.18-CH.34 for the links from on-board-units to RAUs. Two on-board units are equipped in each driver’s room which is located at the head and end of train, as shown in Figure 15. Both on-board units are complementally connected to the trackside RAUs to continuously maintain link connection. The linear cell configuration is introduced to effectively utilize the features of millimeter-wave propagation characteristics.

Figure 14 Channel arrangements of 100 GHz RSTT

of 42

APT/AWG/REP-94

Figure 15 Liner cell configurations of 100 GHz RSTT

3.3 RSTT Deployment in Korea

3.3.1 Deployment of LTE-R systems

3.3.1.1 Service overview of LTE-R system

LTE-R, LTE based railway mobile communication system, provides train control data service, voice call, data and video service for railway communication and applications. The LTE-R of KRNA (Korea Rail Network Authority) is a wireless communication system optimizing the fourth generation cellular system, LTE by 3GPP, as a system for train control center maintainers. LTE-R provides train control data service, voice call, data and video service. Train control data service conducts train status monitoring and train control for safe operation by communicating between control center and train mobile station. Voice call service is needed for train control center manager, train driver, train officer and maintenance workers on the track. It provides private call, emergency call, group call, multi-party voice call and direct call between terminals. It has to support less than 300ms timing delay. Data service is needed for train control center manager, train officer and maintenance workers on the track. It provides train operation data, on-site maintenance data, train approaching warning data and track related data. Video service is a service for transmitting video information with high data rate.

of 42

APT/AWG/REP-94

Figure 16 Service overview of LTE-R Service concept of LTE based railway mobile communication system

3.3.1.2 System Characeeristics

This system is based on the 3GPP Release 12 basically and Release 13 optionally including D2D function. The RF device shall send and receive signals having 10MHz channel bandwidth in 700MHz band (upward 718~728MHz, downward 773~783MHz).

TABLE 1 Technical characteristics of LTE-R systemParameter Technical characteristics

Frequency range (MHz) Uplink: 718-728 MHz, Downlink: 773-783 MHz

Number of channels 1

Channel separation (kHz) 10 MHz

Transmitting radiation power (dBm) 23 dBm (UE), 46 dBm (BS)

Transmission data rate Downlink: Max 75 Mbit/s, Uplink: Max 37 Mbit/s

Modulation Downlink: OFDMA, Uplink: SC-FDMA

Multiplexing method Full Duplex FDD

3.3.1.3 Deployment of LTE-R

The Ministry of Land, Infrastructure Transport (MOLIT) established the LTE-R deployment plan for installation on all regular and high-speed railway lines by 2027. KRNA has developed the Long Term Evolution– Railway (LTE-R) with the integrated public network frequency (700MHz band) from the Ministry of Science and ICT (MSIT) in order to cope with the demand for the high-tech and intelligent railway service. The verification was completed at Kyungkang Line (Wonju ~ Gangneung) in 2017. Presently, KRNA have deployed LTE-R systems for railway operations in Kyungkang Line, Inchon Airport Train Line, and Sosa-Wonsi Line and will deploy LTE-R system over all train lines of Korea by 2027 continuously.

of 42

APT/AWG/REP-94

Figure 17 Railway Lines of Korea

3.3.1.4 Basic structure of LTE-R

LTE-R provides voice group call services, high-speed data services, video services to support railway communication services, and train control data service for safe operations of a train. Railway communication services are provided by interworking between LTE-R mobile network and LTE-R terminal. Train control data services are served by interworking among LTE-R mobile network, location detection equipment, and train mobile terminal. The structure of the LTE-based railway communication system is shown in Figure 18.

Figure 18 Basic architecture of LTE-based railway communication system

of 42

APT/AWG/REP-94

LTE-R mobile network shall guarantee availability and reliability to provide voice service, video service, and data service as well as train control data service. It shall also provide interworking with PS-LTE as well as the legacy railway communication network such as ASTRO and TETRA TRS. LTE-R terminal has two types of terminals; hand-held terminal and train-borne equipment. Train-borne equipment is installed on train engine control room. Train control system consists of train control center, radio block center (RBC), and location detection equipment installed on railway track (a.k.a. balise). Train control system traces current position information of running trains and provides train control information in association with safe operations of train.

3.3.1.5 Design Principle of LTE-based railway communication system (LTE-R)

The LTE-based railway communication system shall provide voice, video call and data service, and train control data service simultaneously through the broadband transmission capability of the 700MHz band LTE communication. It supports a priority policy and control that guarantees the quality of service (QoS) according to the importance level of the service.

LTE-R shall supply voice service, video service, and data service without any interruption during inter-cell / inter-base station handover even on the train running at a speed of 350 km/h.

In addition, inter-RBC handover shall be supported to train control data service as well. Since the train control data service greatly affects the safety of the train when the train control information is not correctly transmitted, specific standards for ensuring the availability and reliability of the LTE-R mobile network shall be specified.

The frequency interference mitigation ways shall be considered in the LTE-R system due to sharing the same frequency band with the PS-LTE. The voice communication between the two systems shall be possible. Furthermore, it is essential to support interworking with legacy systems such as VHF, ASTRO, and TETRA communication system.

In LTE-R, voice call service, data service, and video call service use a hand-held terminal and train control data service uses train-borne equipment. Therefore, performance indexes for these services are presented because these services require different configurations on their wireless networks and have some difference in terms of the required performances.

3.3.1.6 LTE based Railway Communication System Architecture

Portable terminal

Figure 19 Basic architecture of the portable terminal

of 42

APT/AWG/REP-94

The LTE/wireless LAN dual mobile access device shall provide access to the LTE and the wireless LAN, and the wireless LAN (Wi-Fi) needs to support more than 802.11 b/g/n.

The antenna shall provide non-directional (omni directional) radiation pattern by default. The antenna performance optimization design should be reflected by applying diversity technology, and the antenna should be designed with architecture to minimize interference between the main antenna and the sub antenna.

The LTE modem device shall provide OFDM modulation/demodulation and channel coding according to the LTE specifications.

The portable terminal shall provide a H/W Key for PTT function. This service shall provide voice call, private call, emergency call, broadcasting call, group call, and multi-party voice call.

Voice call, video call, and data service have different QoS according to the service priority.

Mobile station in train

The train mobile station transmits train control data by interworking with the LTE based railway communication network and provides railway mobile communication. To ensure reliability of the train control data communication, it can be configured mobile communication service for train driver and train control data service separately. Figure 20 shows logical function structure of the train mobile station.

Figure 20 Basic configuration of the train mobile station

LTE-R radio access network

The LTE-R radio access network consists of base stations which provide mobile communication. The base station interworks with the core network via IP delivery network. The base station is classified into DU and RRU, and DU can be constructed and centralized by region.

The base station, which provides mobile access with the terminal through OFDMA (downward) and SC-FDMA (upward) ways, interwork with the LTE-R core network via IP network. A variety of base stations, such as standard type, small cell, etc. shall be applied by considering

of 42

APT/AWG/REP-94

traffic and coverage by topology, such as city, outskirts, train station in-building, in the office, etc.

Figure 21 Configuration diagram of the LTE-R radio access network

LTE-R core network

The LTE-R core network consists of EPC, IMS, QoS control system, etc. It takes charge of functions for control of multimedia service, such as subscriber management of railway communication system, processing of various service call, routing, interworking between networks, etc. VoLTE interworking with the PS-LTE and roaming processing of the PS-LTE subscribers are based on IMS. IMS functions can be configured optionally depending on the interworking structure of the external network (PSTN, other IMS network, etc.)

Figure 22 Configuration diagram of the LTE-R core network

3.3.1.7 LTE-R network in METRO

Busan metropolitan city has deployed LTE-R network for railway operations including voice communication. It uses same system as LTE-R system of KRNA.

of 42

APT/AWG/REP-94

3.3.2 Deployment of Other communication systems

Korea railway communication systems are using some wireless technologies including VHF, TRS, TRPD, and video transmission system.

150 MHz band RSTT

150 MHz system provides point-to-point radiocommunication scheme between control centre/base station and a train crew or inter-mobile station radio communications in conventional train. VHF system uses four channels for exchanging data at the 153 MHz frequency band. Since the radiocommunication is established by voice call depending on propagation range, users must be careful to be in radiocommunication range. Due to point-to-point scheme, various radiocommunication functions such as group radiocommunication, priority radiocommunication are not supported. Furthermore, the main requirement for railway wireless networks, i.e. safety, reliability, and security, are not guaranteed. TABLE 3 shows technical characteristics of VHF system. TABLE 4 presents channel arrangement for VHF system.

TABLE 3 Technical characteristics of VHF systemTechnical Parameters Technical characteristics

Frequency range (MHz) 153


Channel separation (kHz) 25

Antenna gain (dBi) 3

Transmitting radiation power Base statin: 25 W, Train: 25 W, Portable terminal: 3-4.8 W

Receiving noise figure (dB) –113

Transmission data rate (kbit/s) 9.6

Modulation FM

TABLE 4 Channel arrangements for VHF systemItem CH Tx Rx

Portable terminal

(worker, driver)

1 (Normal) 153.440 MHz

Same as Tx2 (Emergency) 153.250 MHz

3 (Work) 153.280 MHz

4 (Work) 153.660 MHz

Portable terminal

(shunter)

1 (Normal) 153.440 MHz

Same as Tx2 (Emergency) 153.340 MHz

3 (Work) 153.740 MHz

4 (Work) 153.660 MHz

Mobile terminal

(crew)

1 (Normal) 153.440 MHzSame as Tx

2 (Emergency) 153.520 MHz

3 (Work) 153.590 MHz 153.110 MHz

4 (Work) 153.620 MHz 153.200 MHz

of 42

APT/AWG/REP-94

Base station

1 (Normal) 153.440 MHzSame as Tx

2 (Emergency) 153.520 MHz

3 (Work) 153.110 MHz 153.590 MHz

4 (Work) 153.200 MHz 153.620 MHz

800 MHz band RSTT

Korea is using two TRS (Trunked Radio System) schemes, i.e. TRS-ASTRO and TRS-TETRA. TRS-ASTRO uses FDMA (Frequency Division Multiple Access) which uses one channel per 12.5 kHz. TRS-TETRA uses TDMA (Time Division Multiple Access) and provides four channels with 25 kHz bandwidth. Table 5 shows technical characteristics of TRS system.

TABLE 5 Technical characteristics of TRS-ASTRO and TRS-TETRA system

Technical ParametersTechnical characteristics

ASTRO TETRA

Frequency RangeUplink: 806-811 MHz,

Downlink: 851-856 MHz

Uplink: 806-811 MHz,

Downlink: 851-856 MHz

Channel separation 12.5 kHz, 25 kHz 25 kHz

Antenna gain 3 dBi 3 dBi

Transmitting radiation powerBase station: 70 W, Train: 30W,

Portable terminal: 3W

Base station: 25 W, Train: 3W, Portable

terminal: 1W

Receiving noise figure –118 dBTerminal: –112 dB,

Base station: –125 dB

Transmission data rare 9.6 kbit/s 36 kbit/s

Modulation C4FM (Continuous 4 level FM) π/4 DQPSK

Multiplexing method FDMA TDMA

TRS provides voice service such as one-to-one call, one-to-many call, group call, emergency call, and direct call as well as data service such as message and packet transmission. TRS-TETRA has versatile availability for railway wireless network compared with TRS-ASTRO and VHF.

400 MHz band RSTT

TRPD (Train Radio Protection Device) in 400 MHz band provides accident information to adjacent trains to avoid additional accidents. This system has a wireless train protection function which is installed on the train for the railway vehicle the event of emergencies such as accidents and dangerous situations. It promptly informs and makes stop or decrease speed of the nearby to prevent from subsequent accidents.

TABLE 6 Technical characteristics of TRPD systemTechnical Parameters Technical characteristics

Frequency range 433.3125 MHz


Channel separation 12.5 kHz

of 42

APT/AWG/REP-94

Technical Parameters Technical characteristics

Antenna gain 3 dBi

Polarization Vertical

Transmitting radiation power 36 dBm

e.i.r.p. 39 dBm

Technical Parameters Technical characteristics

Receiving noise figure Under 2

Transmission data rare 8 kbit/s

Transmission distance 4 km

Modulation GMSK (Gaussian Minimum Shift Keying)

Multiplexing method Single

18 GHz band RSTT

Platform Video System provides video streams to driver from the camera when the train enters to the platform of a station to monitor the clearance of the trackside.

TABLE 7 Technical characteristics of platform video systemTechnical Parameters Technical characteristics

Frequency range 18.86-18.92 GHz, 19.20-19.26 GHz


Channel separation 10 MHz

Transmitting radiation power 100 mW

Transmission distance 1.5-2.5 km

Modulation OFDM

4. RSTT field testing studies in APT countries

4.1 RSTT field testing study in China

4.1.1 GSM-R field testing study in China

Hangzhou-Changsha passenger dedicated line, which contains three deployment scenarios, is chosen as an ordinary GSM-R deployment line. The result of GSM-R field testing study of Hangzhou-Changsha passenger dedicated line consists of GSM-R Radio Field Coverage Test and GSM-R QoS Test.

4.1.1.1 GSM-R Radio Field Coverage Test

GSM-R Radio Field Coverage Test contains tunnel, viaducts and Parallel railway lines. Considering the radio field coverage of parallel railway lines is the same as ordinary railway line, result of GSM-R Radio Field Coverage Test including tunnel scenario and viaduct scenario.

ZAOJIAOPO Tunnel is chosen to describe the deployment of GSM-R network in tunnels using single network intertwined coverage. Radio Field Coverage Test result is shown in Figure 23:

of 42

APT/AWG/REP-94

Figure 23 Radio Field Coverage Test in ZAOJIAOPO Tunnel

Part of Hangzhou-Changsha Line is chosen to describe the deployment of GSM-R network along viaducts using single network intertwined coverage. Radio Field Coverage Test result is shown in Figure 24:

Figure 24 Radio Field Coverage Test result along viaduct in Hangzhou-Changsha Line

4.1.1.2 GSM-R QoS Test

GSM-R QoS test includes Break period and success ratio of handover, Call establish time and failure Ratio of Mobile Station to Fixed Terminal, Circuit Switch Data connection time delay and failure Ratio, Circuit Switch Data End-To-End Time Delay, GSM-R Packet Switch Data Transmission Delay and GSM-R Packet Switch Data transmission throughput.

TABLE 8 Break period and Success ratio of handoverHandover(#) Success Ratio % Break Period<500ms %

1972 99.75% 100%

TABLE 9 Call establish time and failure Ratio of Mobile Station to Fixed Terminal

Call(#) Failure RatioCall Establish Time

<5s <7.5s

249 0.4% 99.6% 100%

TABLE 10 Circuit Switch Data connection time delay and failure Ratio

of 42

APT/AWG/REP-94

Connection times(#) Failure Ratio

Data connection time

<8.5s ≤10s

1227 0.08% 99.76% 100%

TABLE 11 Circuit Switch Data End-To-End Time DelayEnd-To-End Time Delay <0.5s Test time (h)

100% 2.39

TABLE 12 GSM-R Packet Switch Data Transmission Delay128 byte 1024 byte

PING times(#) Average Delay（s） PING times(#) Average Delay（s）5118 0.24 2146 1.53

TABLE 13 GSM-R Packet Switch Data transmission ThroughputDownload Upload

Test time（h）

Peak Throughput（Kbps）

Average Throughput（Kbps）

Test time（h）

Peak Throughput（Kbps）

Average Throughput（Kbps）

3.31 107.44 28.74 2.09 62.96 17.27

4.2 RSTT field testing study in Japan

4.2.1 Digital Train Radio System (Digital TRS) field testing study

The Coverage of Digital TRS is measured by an electric and track inspection train periodically. Figure 25shows an example of received signal strength indication (RSSI) of downlink in non-tunnel area. The vertical axis shows RSSI and the horizontal axis shows position of the train. As the RSSI is expected to be above nearly 0dBuV, this area is no problem for Digital TRS.

Figure 25 Example of downlink RSSI of Digital TRS

4.2.2 Digital Radiocommunication system for High Speed Trains (Digital RHST) field testing study

The Coverage of digital RHST is measured by an electric and track inspection train periodically. Figure 26 shows an example of received signal strength indication (RSSI) of downlink in non-tunnel area.

of 42

APT/AWG/REP-94

The vertical axis shows RSSI and the horizontal axis shows position of the train. The first diagram shows down link f1 RSSI measured through ANT1, the second diagram shows down link f1 RSSI measured through ANT2 and so on. ANT1 and ANT2 are installed at both side of the car and ANT1 is the nearer side to LCX in this example. The RSSI is expected to be above nearly -90dBm at ANT1, this area is no problem for Digital RHST.

Figure 26 Example of downlink RSSI of Digital RHST

4.2.3 100 GHz RSTT field testing study

4.2.3.1 100 GHz RSTT Transceiver characteristics

In the field testing studies, the central control station and the trackside RAU whose blockdiagram is shown in Figure 27are used for field testing studies. Figure 28 shows the detailed configuration of the trackside RAU whose functions are frequency up/down conversions and frequency multiplication.

of 42

APT/AWG/REP-94

Figure 27 Blockdiagram of central control station connected with trackside RAU through RoF technologies

Figure 28 Blockdiagram of trackside RAU

Although the requirement of the phase noise of the local oscillator is not specified in the system design, -105 dBc/Hz at 10-kHz offset of a phase noise is achieved by a phased locked loop technology, as shown in Figure 29. The output power level of the trackside RAU transmitter in the frequency range 97.5-99.5 GHz is shown in Figure 30. The gain of trackside RAU in the input power range from -30 to -5 dBm is about 25 dB.

of 42

APT/AWG/REP-94

Figure 29 Phase noise of Phase Locked Loop (PLL) local oscillator

Figure 30 Output power level of trackside RAU transmitter

of 42

APT/AWG/REP-94

Figure 31 External view of trackside RAU without antenna radome

Figure 31 shows the external view of trackside RAU whose antenna type is cassegrain and antenna diameter and gain are 20 cm and 42dBi, respectively. The antenna pattern at 96 GHz is shown in Figure 32.

Figure 32 Antenna pattern

In the field test study, CH.6-CH.9 are assigned for downlink and CH.13- CH.16 for uplink, as shown in Figure 33. Figure 34 shows spectrum mask of QPSK modulated 4-channel bonding pattern of ch. 6, ch. 7, ch. 8 and ch. 9 whose center frequencies are 95.1 GHz, 95.5 GHz, 95.9 GHz and 96.3 GHz, respectively.

of 42

APT/AWG/REP-94

Figure 33 Channel arrangement used for field testing.

Figure 34 Spectrum mask of QPSK modulated 4 channels bonding pattern whose channel number is no. 6 (center frequency=95.1 GHz), no. 7 (95.5 GHz), no. 8 (95.9 GHz) and no. 9 (96.3 GHz)

4.2.3.2 Filed test in Hokuriku Shinkansen

Hokuriku Shinkansen is selected for field testing site and several trackside RAUs are placed in along the line, as shown in Figure 35. On-board equipment is not equipped in the driver’s room but in the last vehicle to maintain the field of view from the driver’s position in this experiment. The distance between trackside RAU 1 and RAU 2, and RAU 2 and RAU 3 are 611m and 457 m, respectively. These locations are decided taking into account the conditions of line environment such as line curve.

Figure 36 shows the data rate and RSSI as a function of the distance from station. A data rate of 1.5 Gb/s between train and trackside has been achieved at a vehicle speed of 240 km/hour. Although the total experimental distance is about 1.5 km, it is demonstrated that a single

of 42

APT/AWG/REP-94

frequency linear cell configuration, as shown in Figure 15, using radio over fiber technologies can be used for high-speed-train RSTT systems.

Figure 35 Schematic illustration of experimental setup in Hokuriku Shinkansen

Figure 36 Data transmission experiment at a vehicle speed of 240 km/hour

4.3 RSTT field testing study in KOREA

4.3.1 LTE-R verification test

KRNA had performed the verification test in Honam line between Jeungeup –Iksan stations. LTE-R shows capability to support the communication services up to 350km/h and has been demonstrated quality of system at 300km/h speed. LTE-R covered more than 98% of service coverage and transmit the data more than 30 Mbps in the point of view of throughput.

of 42

APT/AWG/REP-94

Figure 37 Iksan-Jeongeup testbed in Honam Line

Some performance indexes were used for voice call service, data service and video call service as follows:

RF Signal Received Power -RSRP

When the reference signal from a base station is transmitted to LTE-R terminal on the train running at a speed of 350 km/h, the voltage power of received reference signal at the LTE-R terminal indicates the RF Signal Received Power (RSRP). It shall meet a level of 98% of –95 dBm within coverage. However, in case of a network dedicated to a voice call, an additional criterion can be applied

Voice call setup time

Voice call is provided by PTT-based voice call and VoLTE-based voice call. The call setup time of PTT-based voice call is the time from the moment a hand-held terminal presses PTT button until the moment it receives a response allowed a call from the LTE-R (KPI 1)1). And it shall be done within 300ms. And end-to-end setup time of PTT-based voice call is 1000 msec on the same network. The call setup time of VoLTE-based voice call is the time from the moment an originating terminal sends originating message (Assume that the originating terminal is registered in LET-R) until the moment it receives the ringing message, and it follows the connection standard in the commercial network.

Emergency Call Setup Time

Emergency call has public emergency call (such as 119, 112, etc.) and train emergency call. Public emergency call shall meet the call setup time which is defined by commercial emergency call. Train emergency call based on group call has two operation modes, which have train emergency call and shunting emergency call. Train emergency call is determined by the train situation. If the emergency button is pressed in shunting mode, shunting emergency call is initiated. And if the emergency button is pressed in emergency situation, emergency call is

of 42

Iksan

Jeongeup

APT/AWG/REP-94

initiated. If train emergency call is initiated, group call procedure shall be done among the train manager, driver and related officer, and shall be reported to radio block center (RBC). And it shall have the highest service priority to reduce the delay of the call setup time.

Data Reception Success Rate

It means the data reception success rate between LTE-R terminals and the data reception success rate between the train control center and the LTE-R terminal when the data service occurs in the train or the train control center.

Video Data Reception Success Rate

It means the video data reception success rate between LTE-R terminals and the video data reception success rate between the train control center and the LTE-R terminal when the video data service occurs in the train or the train control center.

Data Transfer Delay

It means the data transfer delay between LTE-R terminals and the data transfer delay between the train control center and the LTE-R terminal when the data service occurs in the train or the train control center.

Handover Success Rate

It means the handover success rate between RRUs and between DUs on environment where the train runs at a speed of 350 km/h.

TABLE 13 Performance Index of Voice call service, Data service, and Video call serviceQoS Parameter Performance Index

RF signal received power RSRP -95dBm (more than 98% wireless coverage)

PTT-based voice call connection time 300ms, the time from the moment a hand-held terminal

presses PTT button until the moment it receives a response

allowed a call from the LTE-R railway communication

network (KPI 1)

PTT-based voice call end-to-end call setup

time

1000msec, end-to-end setup time of PTT-based voice call

on the same network (KPI 2)

VoLTE-based voice call setup time Within 1000 ms at the speed of 350km/h

Railway emergency call setup time Within 300 ms at the speed of 350 km/h and call setup

success rate is above 99%

Data reception success rate Above 99% at the speed of 350 km/h

video data reception success rate Above 99% at the speed of 350 km/h

Data transfer delay Within 300 msec at the speed of 350km/h

handover success rate Above 99% at the speed of 350 km/h and the average

handover switch time is within 300 msec

Other performance indexes were used for data service in train control as follows :

RF Signal Received Power

of 42

APT/AWG/REP-94

It means RSRP to be used for deciding wireless coverage of 98% on the railway where a train is running at the speed of 350km/h.

Train Control Data Reception Success Rate

It means the data reception success rate at the train mobile terminal when the train control center sends train control data to the train mobile terminal through a wireless network.

4.3.2 Wonju-Pyungchang field test

KRNA has constructed 112 km Gyunggang line for Winter Olyimpic Game 2018 and performed communication tests over the 1,930 m between MyunOn Tunnel – Jinjo Tunnel by KT.

Figure 38 Gyunggang line

TABLE 14 shows items tested in Gynggang line.

TABLE 14 Test items and resultsNo. Test item Criteria Results

1LTE-R Network

ConfigurationThe adequacy cell planning Passed

2 Redundancy EPC, DU redundancy Passed

3RRU distance (Tunnel,

Open space)Coverage redundancy

Passed (Tunnel 800 m,

Open space 800 m)

4 DU Handover Above 99% Passed (100%)

5 RRU Handover Above 99% Passed (100%)

6 Signal strength 41~48dBm Passed (46.62dBm)

7 CoverageAbove 98%

(RSRP above –110dBm )Passed (98.8%)

8 Call setup time

Emergency call : less than 2 sec 100%

Group call: less than 2.5 sec 100%

Other call : less than 5 sec 100%

Passed (100%) Passed

(100%) Passed (100%)

9 Handover Success rateOpen space : Above 99%

Tunnel : Above 99%

Passed (100%) Passed

(100%)

10 Call setup Success rate Above 99% Passed (100%)

of 42

APT/AWG/REP-94

11 Call drop rate One time per 100 hours Passed (0 times)

12Data Transmission

Success rateAbove 99% Passed (100%)

13Data Transmission Delay

timeBelow 600ms Passed (28ms)

14Loss rate of continuous

packetsLess than 5 sec drop in data transmission Passed (0s)

15 Network registration time Below 500ms Passed (414ms)

16 Voice quality in OBE Above MOS 3.0 Passed (MOS 3.0)

4.3.3 LTE-R field testing

Osong railway test line, been completed in April 2019 is a 13 km railway line from Gongdong-myeon, Osong-eup to Sejong-si, Cheongju, Chungbuk province.

The Osong test line is a dedicated line capable of carrying out 477 kinds of performance tests in all fields required for construction and operation of railway.

The field test result for the LTE-R is based on the results from the Osong test line.

The train runs at a maximum speed of 250 km/h, and is a test line that can be used to verify the performance of railway equipment, vehicles, and systems.

Figure 39 Osong testbed line

4.3.3.1 LTE-R Radio field Coverage test

The results are based on the combined operation test on the trial operation trains.

LTE-R Radio Field Coverage Test contains radio field coverage of railway lines with throughput.

of 42

APT/AWG/REP-94

Figure 40 Field coverage test

TABLE 15 Coverage Test

RSRP Value

Coverage

KR Standards requirement

Measured Value

(Miminum/Maximun)

Measured Value

(Average)

Criteria RSRP

Satisfied Regions

Ratio

-110dBm Above

98% Above-96dBm/-34dBm -71.25dBm 100%

TABLE 16 Transmission speed TestMeasured Value (Maximum throughput) Measured Value (Average)

Downlink 69.14 49.54

Uplink 22.76 17.06

LTE-R QoS Test included call setup time, MOS Test, Call quality, Data transfer success rate, Data transfer delay time.

TABLE 17 Call setup timeCases of Call setup time KR Standards requirement Measured Data

Voice call 2Sec 0.599Sec

PTT Call 2.5Sec 0.6Sec

PTT Group Call 2.5Sec 0.4Sec

TABLE 18 MOS TestKR Standards requirement Measured Data

3.0 Above 4.14~ 4.31

of 42

APT/AWG/REP-94

TABLE 19 Data transfer success rateKR Standards requirement Number of test calls /Success Success Ratio

99% Above 600/600 100%

TABLE 20 Data transfer delay timeKR Standards requirement Measured delay time

(Minimum/Maximum)

Average of delay time

300ms below 21ms/136ms 34ms

5. Studies on radio propagation characteristics under high speed movement in typical scenarios

5.1 Relevant radio propagation study in China

The propagation characteristics in high-speed trains are important for the planning of railway systems, and propagation models are also useful to facilitate global or regional harmonized frequency bands in RSTT. These propagation characteristics consist of propagation loss, large-scale fading characteristics, small-scale fading characteristics, Doppler effects and etc.

Base on measured data at frequency 932MHz in high-speed trains environments in China, the propagation losses between measured data and Recommendation ITU-R P.1546 are compared, the mean and root mean square (r.m.s.) values of prediction errors are given in six scenarios such as plain-viaduct, hilly terrain, urban, station, cutting, tunnel.

5.1.1 Propagation scenarios

There are six propagation scenarios are analyzed in this document, different scenarios have different propagation parameters. The base station is besides the railway line, and the receiver is on the top of the train. The railway line of straightness is analyzed, without consideration of bending conditions. The speed of trains is mostly more than 200 km/h. The received signal level is recorded every 4 centimeters, so 2500 statistic samples can be obtained every 100 meters. A statistical analysis is made in every 100 meters to get the signal level of 50% location probability.

Figure 41 Diagram of the Base Station and Mobile Station in HSTs

In the plain-viaduct scenario, the topographic relief in both sides of railway is very small and the cropland and Gobi desert are the main scenes. The HSTs operate on viaducts and the height of viaducts is between 10m to 30m. The plain-viaduct scenario is shown in Figure 42(a).

In the hilly terrain scenario, the HSTs always operate on viaducts because of the influence of the hill. The height of hills is 50m to 300m above the railways. The hilly terrain is shown in Figure 42(b).

The urban mainly means large and medium-sized cities. There are 5 to 20 stories buildings on

of 42

APT/AWG/REP-94

both sides of the railway. The urban scenario is shown in Figure 42(c).

In the station scenario, there are awnings above the station and they probably block the line-of-sight rays. For large- and medium-sized station, the awnings are enclosed; for small-sized station, the awnings are semi-enclosed. The station scenario is shown in Figure 42(d).

The cutting is used to ensure the smoothness of the rail and help to achieve a high speed of the train when passing though the irregular terrain. The cutting sides are usually covered with vegetation, and there are always suburban and rural outside the cutting. The cutting scenario is shown in Figure 42(e).

The tunnel is an artificial underground passage, especially one built through a mountain in HSRs environment, as shown in Figure 42(f). Generally, two main base stations are placed at the beginning and the end of the tunnel.

(a) plain-viaduct (b) hilly terrain (c) urban

(d) station (e) cutting (f) tunnelFigure 42 Propagation Scenarios in HSTs

5.1.2 Analysis results

The propagation losses are calculated used with the method in Recommendation ITU-R P.1546-5. Different propagation parameters are considered for different scenarios based on the measured situations, the values of the parameters are shown in TABLE 21.

TABLE 21 Propagation parameters for different scenariosScenarios Height of base station (m) Height of mobile station (m)

Plain-viaduct 57.5 19.5

Hilly terrain 38 4.5

Urban 52.5 14.5

Station 38 4.5

Cutting 38 4.5

Tunnel 23 4.5

of 42

APT/AWG/REP-94

The propagation losses obtained by measurement and P.1546 are shown in Figure 43. The thick red line represents the loss obtained by Recommendation ITU-R P.1546-5, while the thin lines are the measured loss. The mean and r.m.s. values of prediction errors are shown in this Figure. If X represents the prediction error which equals the prediction value minus the measured value, then the mean and r.m.s. value are given by:

of 42

APT/AWG/REP-94

Figure 43 Propagation Loss in Six Scenarios

TABLE 22 Mean and r.m.s. Values of Prediction Errors

scenariosplain-

viaducthilly terrain urban station cutting tunnel

mean (dB) -6.6 0.7 -7.6 1.8 5.0 -0.9

r.m.s. (dB) 9.8 6.2 14.5 7.7 9.5 9.4

From TABLE 22, it can be seen that the urban scenario has the maximum prediction errors, and the hilly terrain case has the minimum prediction errors based the measured data. In Recommendation ITU-R P.1546, there are several heights of the ground cover, “Examples of reference heights are 20 m for an urban area, 30 m for a dense urban area and 10 m for a suburban area. For sea paths the notional value of R2 is 10 m.” the ground cover refers to objects, such as buildings or vegetation, which are on the surface of the Earth but not actually terrain. By analyzing the data we found that when using this recommendation in high-speed trains’ scenarios, the prediction errors are minimum if the representative of the height of the ground cover is taken 10m. In HSTs, the base station is besides the railway lines, although there are ground covers outside the railway lines, the propagation path between the TX and RX is clear, so it is reasonable in taking the ground cover height of 10m. According to the analysis above, it can be preliminarily concluded that the propagation method in P.1546 can be used in HSTs at frequency bands of 900MHz.

5.1.3 Conclusion

The propagation losses for HSTs at frequency bands of 900MHz can be predicted according to Recommendation ITU-R P.1546-5, where R1 (Representative clutter height-around transmitter) = R2 (Representative clutter height-around receiver) =10m.

5.2 Relevant radio propagation study in Japan

5.2.1 LCX propagation study

In Japan, Leakey Coaxial Cable (LCX) based train radio is commonly used for radio communication system for high speed trains (RHST). As LCX is considered to be a line wave source for a train antenna, total propagation loss can be calculated by sum of Line Loss and Coupling Loss as follows.

of 42

APT/AWG/REP-94

Total propagation loss = Line Loss + Coupling Loss

Line Loss is an amount of attention inside LCX between radio source and a mobile antenna and the following formula is used for calculation.

Line Loss = IL * d

IL : inside LCX loss per km (dB/km)d : distance between radio source and a mobile antenna (km)

Coupling Loss is an amount of attention out of LCX to a mobile antenna and the following formula is used for calculation.

Coupling Loss = CL1.5 + 10log10 (r/1.5)

CL1.5 : Coupling Loss outside LCX to a dipole-antenna with distance 1.5m (dB)r : distance between LCX and a mobile antenna (m)

IL and CL1.5 are characteristics of LCX and the following 4 types of LCX are combined to lengthen the distance of propagation as shown in Figure 44. This is called “Grading”.

Type 48 or 488 : CL1.5 = -75dB for 400MHz bandType 47 or 487 : CL1.5 = -65dB for 400MHz bandType 46 or 486 : CL1.5 = -55dB for 400MHz bandType 45 or 485 : CL1.5 = -50dB for 400MHz band

CL1.5 =75dB

450m 450m 400m 100m

1400m

10dB

CL1.5 =65dB CL1.5 =55dB CL1.5 =50dB

Base Station

RSSI at mobile station

Repeater

CL1.5 =75dB

Figure 44 LCX Grading

5.2.2 100 GHz propagation study

Recommendation ITU-R P.1411 provides propagation data and prediction methods for the planning of short-range outdoor radiocommunication systems and radio local area networks in the frequency range 300 MHz to 100 GHz. The working document towards a future preliminary draft revision of Recommendation ITU-R P.1411 includes 90 GHz band propagation model and delay spread model for railway environment which are very useful information to design 100-GHz RSTT. The following TABLE is extracted from Annex to the working document towards a future preliminary draft revision of Recommendation ITU-R P.1411.

TABLE 23 Path loss coefficients for millimeter-wave propagation in the railway scenario

of 42

APT/AWG/REP-94

Frequency

(GHz)

Type of

environment

Half power beam

width (degree) PolarizationAntenna

height (m)Range (m)

Path loss

exponent

TX Ant RX Ant n

93.56(1) Viaduct(2)10 10 VV 2 10-500 1.73(3)

10 10 VV 1 10-500 1.51(4)

(1) Bandwidth of measurement was 2.16 GHz. (2) TX and RX antennas are inside the viaduct. The width and sidewall height of the viaduct are 3.45 and

1.24 m, respectively.(3) Antenna height is higher than the sidewall height of the viaduct. (4) Antenna height is less than the sidewall height of the viaduct.

TABLE 24 r.m.s. delay spread

Measurement conditionr.m.s. delay

spread (ns)

ScenarioCoverage

scheme

Frequency

(GHz)

Antenna

height (m)Range (m) 50% 95%

Viaduct(1)Direct

link93.56

2 10-500 0.35(2) 13(2)

1 10-500 0.79(3) 21(3)

(1) TX and RX antennas are inside the viaduct. The width and sidewall height of the viaduct are 3.45 m and 1.24 m, respectively. Bandwidth of measurement was 2.16 GHz.

(2) Antenna height is higher than the sidewall height of the viaduct. Vertical polarization. (3) Antenna height is less than the sidewall height of the viaduct. Vertical polarization.

6 List of acronyms and abbreviations

ANT Antenna

BSC Base Station Center

BS or BTS Base Station

CTC Centralized Train Control Centre

CU Central Unit

CS Control Station

CSD Circuit Switch Data

EARS Emergency Alarm Radio System

ETSI European Telecommunications Standards Institute

FT Fixed Terminal

GPRS General Packet Radio Service

GSM-R GSM for Railways

LTE Long Term Evolution

LCX Leaky Coaxial Cable

MS Mobile Station

of 42

APT/AWG/REP-94

NBS Node Base Station

OCC Operation Control Centre

OCS Optical Carrier Station

OFDM Orthogonal Frequency Division Multiplexing

OFDMA Orthogonal Frequency Division Multiple Access

QoS Quality of Service

QPSK Quadrature Phase Shift Keying

RAU Radio Access Unit

RBC Radio Block Centre

RHST Radiocommunication system for High Speed Trains

RSSI Received Signal Strength Indication

RRU Radio Remote Unit

RSTT Railway Radiocommunication systems between train and trackside

TDMA Time Division Multiple Access

TRS Trunked Radio System

UIC Union Internationale des Chemins de fer-(International Union of Railways)

UE User Equipment

UT User Terminal

VSWR Voltage Standing Wave Ratio

7 Reference

APT Report on System Description, Technologies and Implementation of Railway Radiocommunication Systems Between Train and Trackside (RSTT) (APT/AWG/REP-78)

TB 10430-2014: Chinese Specification for engineering test of railway digital mobile communication system (GSM-R)

Annex 7 to Document 3K/256, Working document towards a future preliminary draft revision of Recommendation ITU-R P.1411 - Propagation data and prediction methods for the planning of short-range outdoor radiocommunication systems and radio local area networks in the frequency range 300 MHz to 100 GHz

________________________________

of 42

APT · Web view3.2.1 Deployment of Digital Train Radio System (Digital TRS)7 3.2.2 Deployment of...

Documents

Transcript of APT · Web view3.2.1 Deployment of Digital Train Radio System (Digital TRS)7 3.2.2 Deployment of...