Chapter 19: Mobile Train Radio Communication - LTE PDF

CHAPTER XIX MOBILE TRAIN RADIO COMMUNICATION - LTE 19.0 This chapter covers basic technical information of Long Term Evolution (LTE), Evolved Packet Core (EPC) and LTE based Mobile Train Radio Communication S...

CHAPTER XIX MOBILE TRAIN RADIO COMMUNICATION - LTE 19.0 This chapter covers basic technical information of Long Term Evolution (LTE), Evolved Packet Core (EPC) and LTE based Mobile Train Radio Communication System. This document is based on Specifications of LTE and FRMCS developed by 3rd Generation Partnership Project (3GPP) and International Union of Railways (UIC). 19.1 With GSM, ERA and UIC added extra functionality and called it GSM for Rail, GSM-R. So far the indication is that UIC will try a different approach with LTE and try to get as much functionality into the regular LTE standard, thereby not needing to add extra specific functionality for railways. There are some indications that LTE will end up with more functionality that is valuable to the railway industry than GSM did in its time. The Mobile Train Radio Communication System with LTE technology is in the development stage. 19.2 The International Union of Railways, UIC a global organization for Railway has set up Future Rail Mobile Communications System (FRMCS) project to prepare the necessary steps towards the introduction of a successor of GSM-R. The Future Railway Mobile Communication System - FRMCS has been prepared by UIC in order to have a Mobile Train Communication System based on LTE. 19.3 Limitations of GSM-R:- 19.3.1 As the communication demands increased and the capabilities of electronic devices evolved, it has become necessary to support data communication as much as voice communication. GSM-R does not provide packet-switched transmission. Therefore, data communication must be delivered by Circuit-Switched Data (CSD), which cannot assign the network resources based on the actual demand. This means that data is transmitted over virtual circuits, just like voice frames. Being bursty in nature, data sources send varying amounts of data at irregular intervals. Such a bursty transmission does not fit well into a fixed circuit provided by GSM-R. As a result, circuits are often underutilized and network resources are wasted. 19.3.2 GSM-R is becoming an obsolete technology. The predicted obsolescence of GSM-R is by 2030. Indian Railways Telecom Manual - 2021 Page 253 19.4 LTE: Long Term Evolution:- 19.4.1 Long Term Evolution (LTE) is the latest family of mobile communication standards (4G) developed by 3rd Generation Partnership Project (3GPP). The main requirements for the new access network are high spectral efficiency, high peak data rates, Short round trip time as well as flexibility in frequency and bandwidth. 19.5 Components of Long Term Evolution (LTE):- Fig.-1: Basic EPS Architecture with E-UTRAN Access (Source: 3GPP.org) 19.5.1 The key components of the LTE network sub-system are mentioned below: 19.5.1.1 E-UTRAN: eNodeB (Equivalent of BSS in GSM-R) (Evolved Universal Terrestrial Radio Access Network) The Evolved NodeB (eNodeB) is the base station for LTE radio. eNodeB is the RAN (Radio Access Network) node in the network architecture that is responsible for radio transmission to and reception from UEs( User Equipment) in one or more cells. The eNodeB is connected to EPC nodes by means of an S1 interface. The eNodeB is also connected to its neighbor eNodeBs by means of the X2 interface. Indian Railways Telecom Manual - 2021 Page 254  Fig. 2: LTE Architecture (Source: 3GPP.org) 19.5.1.2 Serving Gateway (S-GW): The gateways (Serving GW and Packet Data Network GW) deal with the user plane. They transport the IP data traffic between the User Equipment (UE) and the external networks. The Serving GW is the point of interconnect between the radio-side and the EPC. As its name indicates, this gateway serves the UE by routing the incoming and outgoing IP packets. It is the anchor point for the intra-LTE mobility (i.e. in case of handover between eNodeBs) and between LTE and other 3GPP accesses. It is logically connected to the other gateway, the PDN GW. 19.5.1.3 Packet Data Network Gateway (PDN-GW): The PDN GW is the point of interconnect between the EPC and the external IP networks. The PDN GW routes packets to and from the PDNs. The PDN GW also performs various functions such as IP address / IP prefix allocation or policy control and charging. 3GPP specifies these gateways independently but in practice they may be combined in a single "box" by network vendors. 19.5.1.4 Mobility Management Entity (MME): The MME deals with the control plane. It handles the signalling related to mobility and security for E-UTRAN access. The MME is responsible for the tracking and the paging of UE in idle-mode. It is the termination point of the Non-Access Stratum (NAS). 19.5.1.5 Home Subscriber Server (HSS): Indian Railways Telecom Manual - 2021 Page 255  The HSS (for Home Subscriber Server) is a database that contains user-related and subscriber-related information. It also provides support functions in mobility management, call and session setup, user authentication and access authorization. 19.5.1.6 Policy and Charging Rules Function (PCRF): The Policy and Charging Rules Function (PCRF), is a combination of the Charging Rules Function (CRF) and the Policy Decision Function (PDF), and ensures the service policy and sends Quality of Service (QoS) information for each session begun and accounting rule information. These policies are enforced in the eNodeB. 19.5.1.7 Policy and Charging Enforcement Function (PCEF): The Policy and Charging Enforcement Function (PCEF) performs policy enforcement and service data flow detection, allowing data flow through the implemented P-GW. It is also responsible for the QoS on IP packets in the P-GW. The PCEF enforces rules that allow data packets to pass through the gateway. 19.5.1.8 IP Multimedia Core Network Subsystem (IMS): IMS is an all-IP system designed to assist mobile operators deliver next generation interactive and interoperable services, cost-effectively, over an architecture providing the flexibility of the Internet. These services include voice, pictures, text and video, or any combination of these with existing services. IMS has become the core component within 3G, cable TV and next generation fixed telecoms networks which deliver Internet Protocol multimedia to mobile users. Fig.3: Non-roaming architecture of 3GPP Accesses (Source: 3GPP.org) Indian Railways Telecom Manual - 2021 Page 256 19.6 Features of Long Term Evolution (LTE):- 19.6.1 LTE is fully packet-switched IP-based mobile communication standard from 3GPP. Both real time services and datacom services will be carried out by IP protocol. LTE network assigns the network resources to users and applications depending on the actual transmission demand. 19.6.2 LTE introduces a simplified core network called Evolved Packet Core (EPC) with fewer elements than in the legacy standards. 19.6.3 The new access solution, LTE, is based on OFDMA (Orthogonal Frequency Division Multiple Access) and in combination with higher order modulation (up to 64QAM), large bandwidths (up to 20 MHz) and spatial multiplexing in the downlink (up to 4x4) high data rates can be achieved. For the downlink, OFDMA (Orthogonal Frequency Division Multiple Access) is used and for the uplink SC-FDMA (Single Carrier - Frequency Division Multiple Access) is used which is also known as DFT (Discrete Fourier Transform) spread OFDMA. The new radio interface offers much higher spectral efficiency than any other legacy mobile communication standard. Modulation and coding schemes are dynamically chosen in LTE based on the radio conditions and the traffic demand. The link adaptation mechanism allows the network to balance between throughput and reliability of the radio transmission. Fig.-4: OFDMA and SC-FDMA (Source: 3GPP.org) 19.6.4 Frequency: LTE is developed for a number of frequency bands – E-UTRA operating bands- currently ranging from 450 MHz up to 5.925 GHz. LTE supports both the time division duplex technology (TDD) as well as frequency division duplex (FDD). 19.6.5 Spectral Flexibility: Indian Railways Telecom Manual - 2021 Page 257 19.6.5.1 E-UTRA shall operate in spectrum allocations of different sizes, including 1.4, 3, 5, 10, 15 and 20 MHz as per 3GPP/ETSI in both the uplink and downlink. Operation in paired and unpaired spectrum are supported. 19.6.5.2 The system shall be able to support content delivery over an aggregation of resources including Radio Band Resources (as well as power, adaptive scheduling, etc) in the same and different bands, in both uplink and downlink and in both adjacent and non-adjacent channel arrangements. A “Radio Band Resource” is defined as all spectrum available to an operator. 19.6.6 Peak data rate (Spectral Efficiency): 19.6.6.1 Instantaneous downlink peak data rate of 100 Mb/s within a 20 MHz downlink spectrum allocation (5 bps/Hz) 19.6.6.2 Instantaneous uplink peak data rate of 50 Mb/s (2.5 bps/Hz) within a 20MHz uplink spectrum allocation) 19.6.6.3 The highest theoretical peak data rate on the transport channel is 75 Mbps in the uplink, and in the downlink, using spatial multiplexing, the rate can be as high as 300 Mbps. 19.6.7 Transmission Latency: The LTE (4G) supports low transmission latency both in User plane and Control Plane. The time taken for data to travel in the air interface between UEs (mobile) to eNodeB (base station) is achieved to be less than 5 ms (User Plane) and time taken for a UE to switch from standby IDLE state to ACTIVE state is less than 100 ms (Control Plane). The User Plane and Control Plane transmission latency are further improved in the 5G system. 19.6.8 Control-plane capacity : At least 200 users per cell should be supported in the active state for spectrum allocations up to 5 MHz. 19.6.9 Mobility: 19.6.9.1 E-UTRAN should be optimized for low mobile speed from 0 to 15 km/h. 19.6.9.2 Higher mobile speed between 15 and 120 km/h should be supported with high performance. 19.6.9.3 Mobility across the cellular network shall be maintained at speeds from 120 km/h to 350 km/h. 19.6.10 Coverage: The Coverage i.e. Cell range depends on various factors like Cell edge throughput requirement, available spectrum and spectrum efficiency Indian Railways Telecom Manual - 2021 Page 258  and mobility target etc. Approximate Cell ranges for 700 MHz LTE and its Cell edge throughput are given below:- 700 MHz LTE Spectrum & cell range Cell Edge User 512 256 128 64 Throughput (Kbps) UL Cell Range (Km) 0.70 1.21 3.37 8.48 19.6.11 Enhanced Multimedia Broadcast Multicast Service (MBMS) : 19.6.11.1 While reducing terminal complexity: same modulation, coding, multiple access approaches and UE bandwidth than for unicast operation. 19.6.11.2 Provision of simultaneous dedicated voice and MBMS services to the user. 19.6.11.3 Available for paired and unpaired spectrum arrangements. 19.6.12 Co-existence and Inter-working with 3GPP Technology : 19.6.12.1 Co-existence in the same geographical area and co-location with GERAN/UTRAN on adjacent channels. 19.6.12.2 E-UTRAN terminals supporting also UTRAN and/or GERAN operation should be able to support measurement of, and handover from and to, both 3GPP UTRAN and 3GPP GERAN. 19.6.12.3 The interruption time during a handover of real-time services between E-UTRAN and UTRAN (or GERAN) should be less than 300 msec. 19.6.13 Architecture and migration : 19.6.13.1 Single E-UTRAN architecture 19.6.13.2 The E-UTRAN architecture shall be packet based, although provision should be made to support systems supporting real-time and conversational class traffic 19.6.13.3 E-UTRAN architecture shall minimize the presence of “single points of failure” 19.6.13.4 E-UTRAN architecture shall support an end-to-end QoS Indian Railways Telecom Manual - 2021 Page 259 19.6.13.5 Backhaul communication protocols should be optimized 19.6.14 Radio Resource Management requirements : 19.6.14.1 Enhanced support for end to end QoS 19.6.14.2 Efficient support for transmission of higher layers 19.6.14.3 Support of load sharing and policy management across different Radio Access Technologies 19.6.15 Complexity : 19.6.15.1 Minimize the number of options 19.6.15.2 No redundant mandatory features 19.6.16 LTE is the latest family of mobile communication standards. Hence, it has much lower obsolescence risk than any of the previous standards. 19.7 Mobile Train Radio Communication System (LTE) :- Fig.5:- LTE Architecture LTE for Railways consists of User Equipment, Evolved Universal Terrestrial Radio Access Network, Evolved Packet Core, IP Multimedia Subsystem (IMS)/ Session Initiation Protocol (SIP) Core and various Applications/Solutions Servers on LTE. The LTE systems are compatible with modern train automation systems like European Train Control System (ETCS) or similar and also interoperable with other legacy mobile communication systems such as GSM and UMTS. Indian Railways Telecom Manual - 2021 Page 260 19.8 Communication Requirement of Railways through LTE (Future Railway Mobile Communication System):- This section looks at various Railway requirements/features as listed by UIC and how it can be satisfied using the LTE based architecture. Indian Railways may include its all other specific requirements as implemented in GSM-R. 19.8.1 Users in FRMCS: The following users are those identified to be users within this document and may not be necessarily conclusive within FRMCS:- Driver(s) Controller(s) Train staff: o Train conductor(s) o Catering staff o Security staff Trackside staff: o Trackside maintenance personnel o Shunting team member(s) Railway staff (excl. all of above): o Engine scheduler(s) o RU operator(s) o Catering scheduler(s) o IM operator(s) o Engineering personnel Station manager(s) o Station personnel o Depot personnel o Etc. Members of the public: o Passengers (on trains, on platforms, at stations, etc.) o Other persons (on platforms, at level crossings, etc.) Systems: o ATC on-board system o ATO on-board system o On-board system o Ground system o Trackside warning system o Trackside system o Sensors along trackside o Trackside elements controlling entities (such as, for example, for level crossings) o Applications (such as, for example, those for monitoring lone workers, for remote controlling of elements) Network operator Public emergency operator Indian Railways Telecom Manual - 2021 Page 261 19.8.2 Communication requirements:- Critical: applications that are essential for train movements and safety or a legal obligation, such as emergency communications, shunting, presence, trackside maintenance, ATC, etc. Performance: applications that help to improve the performance of the railway operation, such as train departure, telemetry, etc. Business: applications that support the railway business operation in general, such as wireless internet, etc. These are the following sub-sections which are in line with the UIC FRMCS document. Critical Communication Applications Performance Communication Applications Business Communication Applications Critical Support Applications Performance Support Applications Business Support Applications Fig.-6: Grouping of FRMCS Applications (Source: uic.org) 19.8.3 Critical Communication Applications:- 19.8.3.1 On-train outgoing voice communication from the driver towards the controller(s) of the train: The driver shall be able to initiate a voice communication to any controller that was, is, or will be responsible for the movement of the train. 19.8.3.2 On-train incoming voice communication from the controller towards a driver: An authorized controller shall be able to set up a voice communication to a driver. Indian Railways Telecom Manual - 2021 Page 262 19.8.3.3 Multi-train voice communication for drivers including ground user(s): The driver shall be able to set up a voice communication with entitled ground user(s) and/or other drivers. A ground user shall be able to set up a voice communication with drivers and other entitled ground user(s). The selection could be based on the location of the train, on the track configuration, etc. using a functional identity. The voice communication can be bi-directional or uni-directional. 19.8.3.4 Banking voice communication: Drivers of different locomotives within the same train shall be able to set up voice communication. During the ongoing voice communication an entitled controller can connect to the communication without any action of the driver(s). The driver is able to invite an entitled controller to connect to the communication. Note – the different locomotives within the same train may or may not be coupled mechanically and/or electrically. 19.8.3.5 Trackside maintenance voice communication: A trackside worker or controller shall be able to set up a voice communication with other authorized users. The voice communication can be bi-directional or unidirectional. 19.8.3.6 Shunting voice communication: A shunting user shall be able to set up an uninterrupted voice communication with other shunting users and/or with entitled controller(s). The voice communication could be a user-to-user or multi-user communication. The entitled controller and other shunting users are addressed by the system automatically (for example, based on location, operational situation etc.). 19.8.3.7 Public emergency call: A user is able to make a public emergency call. 19.8.3.8 Ground to ground voice communication: A ground user shall be able to set up voice communication to another ground user. 19.8.3.9 Automatic train control communication: The provision of a reliable communication bearer to support the implementation of radio based ATC systems. The ATC system shall have a reliable communication bearer in order to ensure efficient data transfer between the on-board system and the ground system. (for example ETCS L2/L3, CBTC, CTCS) , or between a train and other trains or between a train and other trackside elements. This application provides the communication bearer for this data, 19.8.3.10 Automatic train operation communication: The ATO system shall have a reliable communication bearer in order to ensure efficient data transfer between the on-board unit and the ground system, or between a train and other trains or Indian Railways Telecom Manual - 2021 Page 263  between a train and other trackside elements. This application provides the communication bearer for this data. The ATO system components (on-board unit, the ground system or other ATO entities in the trackside) may broadcast information to other ATO system components. This application may include real time video between the on-board and the ground system (for example a train mounted front camera) or between other ATO system components. 19.8.3.11 Data communication for Possession management: The application shall support the processes involved in taking possession of an area of railway infrastructure for engineering purposes (for example for track maintenance). 19.8.3.12 Trackside maintenance warning system communication: The trackside maintenance warning system shall be able to initiate data communication to trackside maintenance workers in the appropriate area. 19.8.3.13 Remote control of engines communication: It shall be possible to set up data communication between an engine and a ground based system in order to control the engine. The remote driver can operate the engine via the ground system. 19.8.3.14 Monitoring and control of critical infrastructure: It shall be possible to set up data communication between infrastructure systems and a ground based or train based system in order to monitor or control critical infrastructure such as train detection, signals and indicators, movable infrastructure, level crossing elements, including barrier controls vehicle sensors, lighting controls and alarms. 19.8.3.15 Railway emergency communication: An authorized user shall be able to set up a railway emergency communication to other users within an automatically configured area or group, which is based upon the originator’s location or characteristics and those users likely to be affected by the emergency 19.8.3.16 On-train safety device to ground communication: Based on a critical situation in the train (for example, triggered by a Driver Safety Device (DSD)), a voice and/or data communication is automatically set up towards a ground user (controller or ground system). 19.8.3.17 Public train emergency communication: This application allows any entitled user involved in train operations to alert, via a voice and/or data communication, the drivers of the concerned trains of a safety related incident in the vicinity of railway infrastructure; for example, at a platform environment or a level crossing: a person falling from a platform or slipping between train Indian Railways Telecom Manual - 2021 Page 264  and platform or a car being stuck on a level crossing. An entitled user in this case could be a member of the public. The controller of the affected track/line(s) shall also be made aware of the alert and shall be able to have voice communication with the alert initiator. 19.8.3.18 Working alone: The system shall be able to monitor the status (location, movements, health, etc.) of a user working alone. Once the application is active, the application can trigger voice and/or data communication applications based on the status of the worker. 19.8.3.19 Voice Recording and access to the recorded data: It shall be possible to enable the recording of, and access to, communication content and the communication related data in order to support analysis. 19.8.3.20 Data recording and access: It shall be possible to enable the recording of, and access to, communication content and the communication related data in order to support analysis. 19.8.3.21 Shunting data communication: A shunting user (e.g. the shunting leader) shall be able to set up an uninterrupted data communication with other shunting users (e.g. the driver) and/or with entitled controller(s)/traffic control system. The purpose of this data communication is issuing request/commands and confirmations related to shunting operation. The entitled controller and other shunting users are addressed by the system automatically (for example, based on location, operational situation etc.). 19.8.3.22 Train integrity monitoring data communication: The train integrity monitoring system shall have a reliable communication bearer in order to ensure safety related data be transfered between the components monitoring train integrity. The FRMCS system shall provide the communication bearer for this data exchange. 19.8.3.23 Public emergency warning: A user is able to receive a public emergency warning initiated by the Public Safety Authority. 19.8.3.24 On-train outgoing voice communication from train staff towards a ground user: The train staff shall be able to initiate a voice communication to any ground user. 19.8.3.25 On-train incoming voice communication from a ground user towards train staff Indian Railways Telecom Manual - 2021 Page 265  A ground user shall be able to initiate a voice communication to train staff. 19.8.3.26 Railway staff emergency communication: An authorized user, is able to set up a railway staff emergency communication to other users within an automatically configured area or group. The area or group is based upon the originator’s location or characteristics and includes those users likely to assist the originator with the emergency. 19.8.3.27 Critical Real time video: This application facilitates the data communication for real time transmission of video images (“video images” may also refer to images coming from other sources, e.g. lidar and/or radar sensors) for critical railway operation. This includes the control of camera movements and –zoom. 19.8.3.28 Critical Advisory Messaging services- safety related: A user shall be able to send and/or receive critical messages, safety related, like (predefined or any) text or pre-recorded voice messages to instruct railway staff about the usage of the infrastructure (for example speed restrictions, overriding of a stopping point). Messages can be exchanged on user-to-user or on multi-user level. 19.8.3.29 Virtual Coupling data communication: The Virtual Coupling system shall have a reliable communication bearer in order to ensure that the safety related data is transferred between the components making part of the Virtual Coupling system. The FRMCS system provides the communication bearer for this data exchange. 19.8.3.30 On-train wireless backbone communications: The enabling of a train-wide communication network requires the provision of a reliable communication bearer to support the implementation of the Wireless Train Backbone (WLTB). The WLTB shall have a reliable communication in order to ensure the efficient data transfer between the on-train Wireless Train Backbone nodes of each rolling stock element in a single train. The FRMCS system provides the communication bearer for this data exchange. 19.8.3.31 Train parking protection: An authorized user shall be able to store information about the protection means of a parked train in a centralized application. The information can be entered manually or be generated by a sensor. 19.8.4 Performance Communication Applications:- 19.8.4.1 Multi-train voice communication for drivers excluding ground user(s): Indian Railways Telecom Manual - 2021 Page 266  A driver shall be able to set up a voice communication to all drivers within an automatically configured area that is based upon the originator’s location. 19.8.4.2 On-train voice communication: A member of the train staff shall be able to initiate a voice communication with one or multiple other members of the train staff (of the same train) 19.8.4.3 Lineside telephony: A user shall be able to set up a voice communication to an entitled controller via lineside telephony. 19.8.4.4 On-train voice communication towards passengers (public address): A user shall be able to broadcast voice information to all passengers of one or multiple trains. The broadcasted information could be real-time or pre-recorded. 19.8.4.5 Station public address: A user shall be able to broadcast vocal information to all passengers at specific locations such as station concourses and platforms. The broadcast information could be real-time or pre-recorded. 19.8.4.6 Communication at stations and depots: The station or depot user shall be able to set up a voice communication with other user(s). 19.8.4.7 On-train telemetry communications: It shall be possible to set up data communication between on-train systems (on the same train or between 2 different trains) or between on-train systems and a ground based system. 19.8.4.8 Infrastructure telemetry communications: It shall be possible to set up data communication between infrastructure systems and/or a ground based system (for example, to support demand forecasting and response, equipment supervision etc.). Note: the data communication can be permanent or intermittent. 19.8.4.9 On-train remote equipment control: A ground based system shall be able to initiate a data communication to relevant on train systems for control purposes, 19.8.4.10 Monitoring and control of non-critical infrastructure: It shall be possible to set up data communication between non-critical infrastructure systems and railway staff or a ground based or an on- board system in order to monitor and control those infrastructure systems remotely. Indian Railways Telecom Manual - 2021 Page 267 19.8.4.11 Non-critical Real time video: This application facilitates the data communication for real time transmission of video images for non-critical railway operation. This includes the control of camera movements and –zoom. 19.8.4.12 Wireless on-train data communication for train staff: Train staff shall be able to use intranet/internet services via a wireless connection in a train. 19.8.4.13 Wireless data communication for railway staff on platforms: It shall be possible for railway staff or railway systems to use intranet/internet services via a wireless connection in railway areas (for example platforms, station areas etc.). 19.8.4.14 Train driver advisory - train performance: A user shall be able to set up data communication to provide advisory information to the train driver in order to optimize the train journey (for example Driver Advisory System (DAS), Traffic management (TM), Power consumption management). 19.8.4.15 Train departure data communications: A user shall be able to set up data communications with other involved users to support the station departure processes. 19.8.4.16 Messaging services: A user shall be able to send and receive non-critical messages like text, recorded voice (for example voicemail), data, pictures, video. Messages can be exchanged on user-to user or a user-to-multi user level. 19.8.4.17 Transfer of data: Transfer of recorded data for post-accident/incident analysis (for example, CCTV, JRU, energy metering data), or any other data that requires to be transferred between users, for example, data from train staff, time table data. 19.8.4.18 Record and broadcast of information: A user shall be able to record a voice or a video information that can subsequently be transmitted to selected users based on their identity and/or location. 19.8.4.19 Transfer of CCTV archives: A user shall be able to bulk transfer CCTV archives between on-board systems or between on-board system and a ground system. 19.8.4.20 Real time video call: A user shall be able to setup a real time video call to other user(s). 19.8.4.21 Augmented reality data communication: Indian Railways Telecom Manual - 2021 Page 268  A user shall be able to setup an augmented reality data communication to the ground system. The ground system overlays information to the video stream presented to the user. Once a user is connected to the ground system, the controller is able to view the augmented reality images visible for the user. The controller is able to add information (or guidance) via the ground system in the augmented reality view which is visible to the user. 19.8.5 Business Communication Applications :- 19.8.5.1 Information help point for public: A member of the public shall be able to set up a voice communication with the responsible ground user or train staff. 19.8.5.2 Emergency help point for public: A member of the public shall be able to set up an emergency voice communication that will be automatically routed to the most appropriate ground user, train staff or driver. 19.8.5.3 Wireless internet on-train for passengers: It shall be possible for passengers to use internet services via a wireless connection in a train. 19.8.5.4 Wireless internet for passengers on platforms: It shall be possible for passengers to use internet services via a wireless connection in railway area(s) (for example platforms, station area(s) etc.). 19.8.6 Critical Support Applications:- 19.8.6.1 Assured Voice Communication The Assured Voice Communication application shall provide a clear indication to the users as soon as an end-to-end voice communication link is broken or as long as the end-to-end communication link is active. 19.8.6.2 Multi user talker control: The system shall be able to limit the number of simultaneous talkers in a multi-user voice communication. An entitled user shall be able to select and de-select user(s) being able to talk in a multi-user voice communication. 19.8.6.3 Role management and presence: A user shall be able to register and deregister to one or more functional identity/ies. A user is able to see which other functional identities are present within a certain context (for example train, region, communication group, Railway Emergency Communication, etc.). Further it shall be possible for the user to identify at any time the function / person who is talking (for example driver, train staff, maintenance staff, platform staff, controller, etc.). Indian Railways Telecom Manual - 2021 Page 269  This application will be responsible for handling the railway role management of the users including the identity registration and deregistration processes. 19.8.6.4 Location services: The system shall be able to store and provide the location of the user(s) or devices. 19.8.6.5 Authorization of communication: The system shall be configurable, so that access to voice and data communications can be controlled through the use of identities. 19.8.6.6 Authorization of application: The system shall be configurable, so that access to applications can be controlled through the use of, for example: identity; user; user-to-user; multi-user; location, etc. The system is able to authorize access to applications. 19.8.6.7 QoS Class Negotiation: The system shall be able to assign different QoS classes in order to fulfill the level of communication quality required by the applications. 19.8.6.8 Safety application key management communication: The applications on board shall be able to authenticate the source of the messages received as a trusted source, and shall be able to detect corruption of the messages received. 19.8.6.9 Assured data communication: The assured data communication application shall provide a clear indication to the users as soon as an end-to-end data communication link is broken or as long as the end-to-end communication link is active. 19.8.6.10 Inviting-a-user messaging: A user can send a message to another user(s) inviting him to join the ongoing voice communication. 19.8.6.11 Arbitration: The system shall be able to perform arbitration between communications competing for the attention of the user. 19.8.7 Performance Support Applications:- None applicable. 19.8.8 Business Support Applications:- 19.8.8.1 Billing information: An entitled user shall be able to obtain information for any type of on- network communication from the FRMCS system in order to be able to generate bills. Indian Railways Telecom Manual - 2021 Page 270 19.9 LTE System Architecture for Indian Railways:- Installing an Ultra-high-speed LTE based communication corridor along IR network would cater to the current and future data and voice needs for Train-Ground and Train-Train communication for improved train operations, passenger safety and passenger security services and remote rail asset monitoring & management. The applications of LTE can be classified under the following three broad categories:- 19.9.1 Passenger Safety & Service: Advanced Signalling systems like European Train Control System (ETCS) Level 2/Train Collision Avoidance System (TCAS). Emergency communications from train to control, train to stations and between train to train, etc. Increased carrying capacity (throughput) Advanced signaling systems allow more trains to run across a given point or segment of the track which effectively increase the carrying capacity (throughput) of the same fixed civil and electrical infrastructure. 19.9.2 Live surveillance camera feeds from trains will ensure security of passengers coupled with video analytics, this can help in prevention and detection of crime, not only in Indian Railways network but also outside in the peripheral areas. 19.9.3 Internal improved Railway management: Staff communication system. Remote monitoring of Railways asset to improve their availability. Indian Railways Telecom Manual - 2021 Page 271  Fig.-7: LTE-R System Architecture for Indian Railways 19.9.4 Indian Railway envisages following applications/facilities which will fuel growth in data usage on deploying LTE technology: i) Indian Railway Automatic Train Protection System (IRATP) through Train Collision Avoidance System (TCAS) which is planned for up gradation to ETCS Level 2 in future or any other similar systems as specified by Indian Railways. ii) Mission Critical Push To Talk (MC PTT) application iii) Video Surveillance System in locomotives for Level Crossing Gate/ Tunnels/ Bridges. iv) Onboard Passenger Information System (PIS) consisting of passenger information display and passenger announcement system. v) Internet of Things (IoT) based Asset reliability monitoring. vi) Onboard Video Surveillance System (VSS) for Passenger Security. vii) Broadband Internet on Running Train (Onboard Wi-Fi facility through LTE). 19.10 TRAI Frequency Band Allocation:- 5 MHz (paired) Spectrum in 700 MHz band (703-748 MHz Uplink & 758-803 MHz Downlink, also specified as Band 28 in 3GPP/ETSI standards) has been allocated to Indian Railways for implementing above services. Indian Railways Telecom Manual - 2021 Page 272 19.11 LTE FDD System Throughput :- No of MIMO All Transmission SISO Transmit Transmission Useabl 2x2 Mode Mode/Syste e m Bandwidth Resour Downli Uplink Uplink Downlink Downlink ce nk Peak Peak Peak Peak Block Peak (Mbps) (Mbps) (Mbps) (Mbps) (Mbps) 16 QAM 64 QAM 1.4 MHz 6 4.4 4.4 8.8 3 4.4 3 MHz 15 11.1 11.1 22.1 7.5 11.1 5 MHz 25 18.3 18.3 36.7 12.6 18.3 10 MHz 50 36.7 36.7 75 25.5 36.7 15 MHz 75 55.1 55.1 110 37.9 55.1 20 MHz 100 75 75 150 51 75 Table.-2: LTE FDD System Throughput 19.12 Uniform Numbering Scheme for Mobile Communication Network for Indian Railways :- A) All mobile users in the LTE network must be assigned a certain addresses or identities in order to identify, authenticate and localize them. The following numbers and identities are assigned for administration of each mobile station in the network. i) IMSI : International Mobile Subscriber Identity The IMSI is a string of decimal digits, up to a maximum length of 15 digits, which identifies a unique subscription. The IMSI consists of three fields: the mobile country code (MCC), the mobile network code (MNC), and the mobile subscription identification number (MSIN). ▪ Mobile country code (MCC): The MCC is the first field of the IMSI and is three digits in length and identifies a country. ▪ Mobile network code (MNC): The MNC is the second field of the IMSI, it is two or three digits in length and is administered by the respective national numbering plan administrator. ▪ Mobile subscription identification number (MSIN): The MSIN is the third field of the IMSI, it is up to 10 digits in length, and is administered by the relevant MNC assignee to identify individual subscriptions. Indian Railways Telecom Manual - 2021 Page 273  Fig.-8 : Structure and Format of IMSI (Source ITU) ii) MS ISDN : Mobile Subscriber International Subscriber Directory Number Mobile Station/Subscriber International Subscriber Directory Number (MSISDN) is a number (Mobile Phone Number) used to identify a mobile phone number internationally. The MSISDN composition follows the international ISDN numbering plan with the following structure: ▪ Country Code (CC), up to three digits; ▪ National Destination Code (NDC), typically two or three digits; ▪ Subscriber Number (SN), a maximum of 10 digits. The structure of the MSISDN will then be as shown in figure: Fig.-9 : Number Structure of MSISDN (Source 3GPP) RDSO has approved and issued Uniform Numbering Scheme for Mobile Communication Network (GSM-R) for Indian Railways. The same scheme shall be applicable for LTE. The IMSI and MSISDN for Indian Railway shall be as below:- Indian Railways Telecom Manual - 2021 Page 274  Fig.-10 : IMSI Fig.-11 : MSISDN 19.14 Adaptation of LTE on Indian Railways:- Indian Railway is migrating from GSM-R to LTE for Railway Automation System and Broadband Services. It is proposed that the future projects of Railway Automation System and Broadband Services may be Indian Railways Telecom Manual - 2021 Page 275  designed with LTE. It is also required that LTE system proposed for Indian Railways should be fit for bearer network for TCAS/ETCS Level 2/3 for desired speed. -x-x-x- Indian Railways Telecom Manual - 2021 Page 276