Handbook on Different Types of Telecom Techniques Used in KAVACH PDF

*के वल कार्ालर्ीन उपर्ोग हतुे* *For Official Use Only* Table of Contents ====================================== *Foreword 2* *Preface 3* [*Table of Contents 4*](#table-of-contents) [*List of Figures 7*](#_bookmark1) [*Abbreviatio...

*के वल कार्ालर्ीन उपर्ोग हतुे* *For Official Use Only* Table of Contents ====================================== *Foreword 2* *Preface 3* [*Table of Contents 4*](#table-of-contents) [*List of Figures 7*](#_bookmark1) [*Abbreviations 9*](#_bookmark2) [*Disclaimer 11*](#disclaimer) 1. [*KAVACH - An Overview 12*](#_bookmark5) 1. 1. 2. 2. 3. 4. 2. [*KAVACH -- System Architecture & components 17*](#_bookmark13) 5. 3. 6. 4. 7. 5. 6. 7. 8. 9. 3. [*KAVACH -- Radio Communication 31*](#_bookmark26) 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 10. 11. 12. 4. [*KAVACH -- GSM/ GPRS & GPS/ GNSS Communication 44*](#_bookmark42) 19. 13. 14. 15. 16. 17. 20. 5. [*KAVACH - Failures & Protection 52*](#_bookmark51) 21. 18. 19. 20. 21. 22. 22. 23. 24. 25. 26. 27. 28. 23. 29. 30. 31. 6. *[RDSO's Functional Requirements Specifications of LTE for Proof of Concept for Indian](#_bookmark70)* [Railways 58](#_bookmark70) 24. 25. 26. 27. 28. 29. 32. 33. 34. 30. 35. 31. [*Appendix A: Frequently Asked Questions (FAQ) on KAVACH 63*](#_bookmark83) [*References 67*](#_bookmark85) [*Issue of correction slips 68*](#_bookmark86) [*CAMTECH Publications 69*](#camtech-publications) [*Our Objective 70*](#our-objective) ATP --------- -- BER BIU CA CE CRC CTS DMI DPWCS DTR EoTT EPC EPS E-UTRAN FA FCC FDMA FSK GNSS GPRS GPS GSM HSS IBS IC IMS IoT IPMPLS IRNSS KAS KMS LAN LCD LDA LED LES  LPOCIP -------- -- LSB LTE MA MAC MCPTT MME MMI MVB NMS OFC OTT OVK PCRF PDN PSR PT QCI QoS RF RFID RIU RTC RTS SDMA SIP SMOCIP SNMP SPAD SVK TCAS TDMA TIN TSRMS UHF Disclaimer ========== 1 Chapter ============================== Introduction ------------ ### Need for ATP - It does not indicate speed to go, distance to go, exact location of the train, gradient of track in ahead - Visibility depends on curvature & weather - Higher margin in speed, distance between two trains to be kept - In Block sections, Driver has to drive BLINDLY till he approaches next signal, on TRUST - He has no way to know what is ahead except what he can see with his naked eyes - to be able to prevent a COLLISION 2. ### What is KAVACH? How KAVACH works ---------------- - KAVACH prevents the collision of trains and prevents train from crossing the danger signal, by establishing a UHF Radio communication between the Stationary KAVACH unit and Loco KAVACH unit and Loco-to-Loco Communication. - The Radio Frequency Identification (RFID) tags fitted on track in station section and block section provides Trackside information to Loco KAVACH unit installed in the locomotive. Portions of track including berthing tracks, point and block sections are assigned unique IDs called Track Identification Number (TIN). - The onboard Loco KAVACH unit installed in the locomotive determines the location of train by reading data provided by RFID Tags with the help of RFID reader. - By using the cryptographic technique, malicious attacks will be eliminated. Only Authenticated Systems communicate with each other to ensure the safety of the system. Key Management System (KMS) is developed to check for authentication and distribution of secret keys. - Loco KAVACH unit sets its absolute location (Approaching signal distance from the train position) and Track Identification Number (TIN) as undefined (zero) before determining the direction. - The direction of movement of train shall be determined, when Loco/Train has passed two RFID tags sequentially with Absolute location. - Loco KAVACH unit calculates the location of the train between two RFID tags dynamically based on the distance travelled from last RFID tag through speed sensing arrangement provided on Locomotive. - On passing through the RFID Tag, Loco KAVACH unit transmits the location and direction of the train to the Stationary KAVACH unit through UHF radio antenna provided in locomotive. Thereby, Stationary KAVACH unit gets real-time information regarding Locations, Speed etc. of various trains in its jurisdiction. - Stationary KAVACH is interfaced with station interlocking to acquire real-time dynamic information related with signaling such as various signal aspects, track Circuits and Point Status. Route information of all the signals monitored by a specific Stationary KAVACH unit is configured on the basis of KAVACH Control Table (excluding shunt signals and overlaps). - Separate Stationary KAVACH unit is provided at Mid-Section interlocked Level Crossing Gate and Intermediate Block Signaling (IBS) locations if they do not come within the coverage of station radio tower. - Remote Interface Unit (RIU) shall be used where remote signaling functions are required to be fetched to a nearby Stationary KAVACH unit for example from end cabins/ distributed interlockings or LC gate/IB coming within the radio coverage of station tower. - The Stationary KAVACH shall use the direction of movement of Loco/Train, to find approaching signal of the Loco/ Train. - Based on this information, Stationary KAVACH unit shall then calculate the movement authority for each Loco within its vicinity based on the signal aspect or/and track circuit status or/and route locking status, point position and the status of the berthing track circuit by executing safety algorithm. - Stationary KAVACH unit shall then transmit the Movement Authority (unrestricted safe travel distance) to the Loco KAVACH in its jurisdiction in station area through UHF Radio communication. - The length of the movement authority is decided based on the signal aspect of the approaching Stop Signal. - The Loco unit shall make speed profile/ brake curve for different situations based on movement authority, speed restriction and other information as received from Trackside sub-system. - The Loco KAVACH unit shall display the train speed, the permitted speed, the target distance and the target speed to the loco pilot through a Driver Machine Interface (DMI). - If a signal on approach is Red (Danger), the Stationary KAVACH unit shall transmit this information to the Loco KAVACH and reduce the movement authority to zero. - If loco pilot fails to stop the train, automatic application of brakes shall take place, thus preventing Signal Passing at Danger (SPAD). - In case of any conflict between signal aspect, point position, berthing track section, signal aspect sequence and TIN, the Stationary KAVACH unit shall transmit most restrictive aspect of that signal and shall reduce the movement authority accordingly. In this way, train collisions are prevented in station section. - In case of block section if two trains are detected by Stationary KAVACH to be moving towards each other on same TIN, the SoS command would be generated by Stationary KAVACH for both the trains. - On reception of such Loco specific SoS from Stationary KAVACH Unit, the Trains would be stopped through automatic application of brakes. There is also provision for broadcasting SoS message from Loco KAVACH to other Loco KAVACH in case of emergencies. KAVACH Safety features ------------------------------------------- - Detection and Prevention of SPAD (KAVACH stops the train before the signal) - Cab signalling with Display of movement authority, target distance, speed and signal aspect - Continuous update - Speed Restrictions at turnouts - Adherence/Compliance of Permanent Speed Restrictions - Adherence/Compliance of Temporary Speed Restrictions (under trial) - Automatic Blowing of horn while approaching Level Crossing Gate. - Roll Back/Roll Forward Protection - Head On Collision prevention - Rear End Collision prevention - Side On Collision prevention - SoS Messages during emergency situations - Computation of Train Length - Shunting Limits Validation - Centralized live monitoring of Train movements through NMS 4. Advantages of KAVACH -------------------- - User friendly Cab Signalling - Multi vendor interoperability - Free from monopoly - Suitable for specific requirement & conditions IR - Helpful in Foggy Weather - Helpful at high speeds - Centralized monitoring of real- time train movement Chapter ======= - Trackside Sub-system - Station Sub-system - Loco Sub-system  Trackside sub-system -------------------- ### RFID tag - Suitable for reliable working at train speed up to 200 KMPH (minimum) - Frequency of operation: 865-867 MHz - Can be programmable with minimum 128 bits (including CRC) of user data - Shall be able to work even when submerged in water up to rail level - Under field operating conditions RFID reader antenna shall be able to read, RFID tag from a vertical distance of 700 mm from bottom of RFID reader antenna to top of the rail level. 1. **Track Identification Number (TIN)** a. Each track shall have designated Track Identification Number (TIN). b. Each Block section shall have single unique designated TIN. Block Section TIN can be repeated after a designated distance (50 km minimum along the track route). c. To avoid unnecessary SOS generation, adjacent TINs to be incorporated in the radio packet and adjacent line tag info. Also, location adjustment details shall be sent on radio only after there is physical separation between the tracks. d. Each line in the station section having berthing portion shall have different TINs. TIN can be repeated after a designated distance (10 km minimum along the track route). e. TINs shall be allotted in such a manner not to inhibit permissible simultaneous movements. f. Loco KAVACH unit shall be able to self-deduce the change in its TIN whenever it changes the TIN section. 2. Station sub-system ------------------ - Stationary KAVACH Unit - Tower and Antennae (Discussed in communication chapters) 2. ### Stationary KAVACH Unit 1. Stationary KAVACH vital computer 2. Stationary KAVACH Radio Unit 3. Station Master Operation cum Indication Panel (SMOCIP) 4. Remote Interface Unit (as per requirement) 2. **Stationary KAVACH vital computer** 3. **Stationary KAVACH Radio Unit** - Stationary KAVACH Radio Unit comprises of two UHF full duplex Radio modems with separate cable and antennae in hot standby mode to communicate over RF with Loco KAVACH unit. - The communication between the Radio modems and the KAVACH system is through optical fiber channels.  - There are two serial communication ports available on the Radio modem. One serial port is for Data communication and another serial port is for Set-up of Radio modem. - The Radio Frequency (RF) Antennae are installed on the Tower and the height of the tower is 30 m. - To reduce the losses, the Radio modems are placed near the Radio Tower in a Location Box. Power Supply: 10-30V (24V) - Communication Range : up to 20Km (depends on terrain) - Both are active in alternative cycles. Faulty radio is detected and isolated in 1 minute. - There is feature of automatic recovery of faulty radio - Working frequency : 406 - 470 MHz UHF Channel Bandwidth : 25KHz - Mode of operation : Full-Duplex - Data rate : 19200 bps over-the-air; - Output Power : 10W 4. **Station Master Operation cum Indication Panel (SMOCIP)** 5. **Remote Interface Unit** Loco KAVACH sub-system ---------------------- - Loco KAVACH Vital Computer - RFID Reader - Loco KAVACH Radio Unit with antennas and other communications - Driver Machine Interface (DMI) - Brake Interface Unit (BIU), where required  ### Loco KAVACH Vital Computer - Driver Machine Interface (DMI) consisting of display arrangement & buttons/ switches for operation - Train interface unit & brake interface unit - Radios for communication - GPS for timing and location - Two GSM interfaces for connectivity with centralized Network monitoring System (NMS) and Key Management System (KMS). It shall be also to be operable with LTE where LTE is proved - RFID reader for reading RFID tags on the tracks - Two Direction sensing type Speed Sensor interface for distance and speed measurement - Cab selection keys unit - USB interface for downloading of log & other data for diagnostic purposes  ### RFID Reader ### Loco KAVACH Radio Unit with antennas and other communications 6. **Radio Modem Interface** - Interface : RS 232 - Working frequency : 406 - 470 MHz UHF - Channel Bandwidth : 25KHz - SET UP port -- Diagnosis - DATA port - communication - Mode of operation : Full-Duplex - Data rate : 19200 bps over-the-air; Output Power : 10W - Power Supply: 24V - Two radio modems are used for redundancy  ### Driver Machine Interface (DMI) a. Communication with Loco KAVACH. b. Train type selection by the loco pilot. c. SOS operation by the loco pilot. d. Signal aspect display. e. Train length display f. Train type display g. Display of all modes of loco operation h. Current speed i. Over speed j. Permitted speed k. Target speed (For entering into loop line) l. Movement Authority (MA) m. The function in DMI for displaying the context messages for Loco Pilot's attention 7. ### Brake Interface Unit (BIU)  7. **Working of BIU** g. KAVACH identifies the braking requirement. h. KAVACH communicates braking signal(s) to BIU. i. BIU communicates signals to existing brake system of locomotive The data flow in the KAVACH system is shown in the below figure. Chapter ============================ Introduction ------------ 1. Radio Communication 2. GSM /GPRS Communication 3. GPS/GNSS Communication - Radio communication is used for communication between Stationary KAVACH and Loco KAVACH as well as Loco KAVACH and Loco KAVACH. - GSM (Global System for Mobile Communications)/GPRS (General Packet Radio Service) communication techniques are used for transfer of Authentication keys to Stationary KAVACH and Loco KAVACH through a Key Management System (KMS) Server for establishing radio communication between them. Fault messages from Stationary KAVACH and Loco KAVACH are also communicated to the Network Monitoring System (NMS) through respective GSM interfaces. - GPS (Global Positioning System) and GNSS (Global Navigation Satellite System) are used for time synchronization purposes. 2. Radio Communication ------------------- Initiating Radio communication ------------------------------ - As soon as a train enters a KAVACH territory by reading Signal/Signal Approach/Normal/TIN Discrimination RFID tag, the Loco KAVACH unit shall commence transmission of the Radio message packet to Stationary KAVACH unit. - Before establishing the direction, it shall send Absolute location and TIN as zero along with the last Signal / Signal Approach/Normal / TIN Discrimination RFID tag read, in this packet. - After establishing the direction, Loco KAVACH unit shall commence transmission of absolute location and TIN as per the direction on the basis of data read from RFID Tag. - The Stationary KAVACH unit shall transmit the Radio message packet to Loco KAVACH unit, if it receives the radio packet from Loco KAVACH unit with valid absolute location and direction. - Whenever Loco KAVACH unit establishes communication with a new Stationary unit for the first time, it shall do so by Random Access Method within the time slots reserved for this purpose on frequency f0. 4. Establishing Radio Communication -------------------------------- - On recognition of radio message from a fresh loco pertaining to the territory of Stationary KAVACH unit, the Stationary KAVACH unit shall allocate a Timeslot and Frequency Channel pair (e.g. f1 & f2) for Communication with that particular Loco unit. - Stationary and Loco KAVACH timeslots and frequency channel pairs shall be approved by User Railway. The frequency pairs allotted for two adjacent stations shall be different (TAN5001). - Once, Loco KAVACH unit receives regular packet from Stationary KAVACH unit, Loco KAVACH unit shall continue further transmission in the frequency channel and time slot as specified in the Access Authority packet sent by Stationary KAVACH unit. - For communication among different Loco KAVACH units in block section, in station area and in emergency situations (SoS, head-on, rear-end collisions), Loco KAVACH shall use transmit frequency (f0) in its designated timeslot. 5. Tower and Antennae ------------------ - RF Communication towers are located near stations and in KAVACH equipped IB huts and LC gates if RF coverage is not available from the nearest Station tower. - Typically, the towers are 40 meters tall and are constructed as lattice structures. - Tower should be designed to meet the requirements of zonal railway as per local wind speed and factor of safety. - Each communication tower carries two sets (TX&RX) of antennae, fixed at the top of the tower, which are connected to two radios. - The radios are installed in a Radio Tower Unit at a height of 10m from the foot of the tower. Fiber optic cables connect the radios to the Station KAVACH. KAVACH Multiple Access Scheme & Radio Communication Protocol ------------------------------------------------------------  - Figure shows pair of frequencies fS1-fM1, fS2-fM2 fSn- fMn allotted for Stationary - The frame cycle is divided into basic 78 time slot position markers (position nos. 1 to 78) each of width 352 bits (18.33m-sec). - Out of 78 time slots, 50 Time slots shall be used for communication between Stationary KAVACH and Loco KAVACH. These timeslots have been marked as M-1 toM-50. - These 50 time slots are distributed among adjacent stations sequentially till the last time slot, thereafter the sequence is repeated. Each station is allotted a block consisting of a number of timeslots in 2000 milli seconds frame. A particular Station KAVACH communicates with all the Loco KAVACH units in its jurisdiction in these allocated time slots in a specific frequency pair (say fS1-fM1for Station 1). The number of time slots allotted to a station depends upon the size of the station. Smaller stations like 3 or 4 line stations shall require less number of time slots, while stations with bigger yards may require more number of timeslots. - The remaining Time slots other than the 50 mentioned as above shall be used by Stationary KAVACH and Loco KAVACH for communication in frequency f0 for various other purposes. - Some specific Time slots in f0 shall be used by the Stationary KAVACH for broadcasting additional emergency (SoS) messages. - Some other Time slots in f0 shall be used by the Stationary KAVACH for broadcasting Access Authority messages. - In below figure, frequencies fS1-fM1, fS2-fM2 fSn- fMn allotted at adjacent stations  - On receipt of radio message from a fresh loco falling in the jurisdiction of Stationary KAVACH unit, the Stationary KAVACH unit shall decide the Timeslot in which that particular Loco unit shall communicate. - Stationary KAVACH and Loco KAVACH shall use different timeslot(s) for communication. It means that Stationary KAVACH and Loco KAVACH shall use their respective timeslot(s) in the Multiple Access within their channel for the transmission. - Although the frame cycles for Stationary KAVACH and Loco KAVACH are different at a particular station, Stationary KAVACH and Loco KAVACH time slots shall not overlap. - The Loco time slots for the same station shall not be adjacent to each other (minimum one time slot gap shall be kept as per TAN5001). - In block section, Loco KAVACH System shall switch its Tx frequency to f0 and shall transmit the radio packet in some specific time slots for communicating with Stationary KAVACH.  - In emergency situation, Locomotive shall additionally transmit on f0 in a particular timeslot and tune back to receive on f0. Transmission of SoS messages by Locomotive on f0 in case of emergency situation shall enable other trains in vicinity to get the immediate message without routing through Stationary Unit. - Loco KAVACH unit while transmitting on frequency f0 shall not interfere with the portion of the frame cycle nominated for transmission of Stationary KAVACH units. 7. Communication in overlap zone ----------------------------- Terminating a Radio Communication ------------------------------------------------------ - When the Loco moves beyond the Last Stop Signal of the Stationary KAVACH Unit as per Boundary configured (typically 1.5 km from Last Stop Signal of Stationary KAVACH). - If the direction is invalid in Standby or Staff Responsible mode. - No radio packet is received from Loco KAVACH for more than 60 cycles. - In the event of failure of both -- GPS/GNSS and RTC, Radio Communication (Over the Air) Requirements (As per RDSO specifications) ---------------------------------------------------------------------------- - Communication between the Stationary KAVACH and Loco KAVACH shall be Over-The- Air using Multiple Access - Each Multiple Access frame cycle shall be of 2000 milli seconds. - It shall be suitable for communication in frequency range of 406 MHz to 470 MHz. - Loco KAVACH shall use transmit frequency (f0) in block section and at the times of emergency situations (SoS, head-on, rear-end collisions). - Stationary KAVACH and Loco KAVACH shall use their respective timeslot(s) in the Multiple Access within their channel for the transmission of communication packet(s). - Communication packets shall be of a maximum size of 1024 bits. - KAVACH sub-system shall split the packet into multiple packets if it exceeds maximum communication packet size (1024 bits). - The transmission Over-The-Air from Radio shall be controlled by KAVACH Subsystems using Request To Send signal in the RS232. - KAVACH sub-system may transmit multiple Communication packets in a single transmission burst. - KAVACH sub-system shall transfer all the data for a single transmission burst to the Radio modem at least 20 millisecond before commencement of Over-The-Air. - KAVACH sub-system shall calculate the timings from commencement and completion of transmission by Radio Modem Over-The-Air by considering the preamble, communication packet, post amble and extra stuffed bits. - KAVACH sub-system shall disable the RTS signal after completion of transmission of information data over-The-Air. - Change of frequency or switch between the frequencies shall be completed well in Advance (15 milliseconds before commencement of Data transmission Over-The-Air). - In the bit-stream Over-The-Air, LSB shall be transmitted first.  Multiple Access Scheme (As per RDSO specifications) --------------------------------------------------- +-------------+-------------+-------------+-------------+-------------+ | **S. N.** | **Time | | | **Remarks** | | | slots** | | | | +=============+=============+=============+=============+=============+ | 1 | P2 to P27 | | | Total 50 | | | | | | Timeslots | | | | | | | | | | | | out of 78 | +-------------+-------------+-------------+-------------+-------------+ | 2 | P28 to P33 | | | Total 12 | | | | | | Timeslots | | | and P67 to | | | out of 78. | | | P72 | | | | | | | | | Shall | | | | | | switch its | | | | | | Txfrequency | | | | | | to f0 in | | | | | | the block | | | | | | | | | | | | section | +-------------+-------------+-------------+-------------+-------------+ | 3 | P34,35,73,7 | | | Total 4 | | | 4 | | | Timeslots | | | | | | out of 78. | +-------------+-------------+-------------+-------------+-------------+ | 4 | P38,39,77,7 | | | Total 4 | | | 8 | | | Timeslots | | | | | | out of 78. | +-------------+-------------+-------------+-------------+-------------+ | 5 | P36,37,75,7 | | | Total 4 | | | 6 | | | Timeslots | | | | | | out of 78. | +-------------+-------------+-------------+-------------+-------------+ | 6 | Four time | | | Total 4 | | | Slots | | | Timeslots | | | P1,P27,P40 | | | out of 78. | | | | | | | | | & P66 | | | | +-------------+-------------+-------------+-------------+-------------+ - Stationary KAVACH System shall transmit the Radio packet in its designated time slot. - Loco KAVACH System shall transmit the radio packet in its designated time slot and designated frequency channel received from stationary KAVACH Unit. - The frequency pair allotted for two adjacent stations shall be different. - The Loco time slot for the same station shall not be adjacent to each other (minimum one time slot gap shall be kept). 11. Radio Modem -------------------------------- - The Radio with a transmission power of 10W is capable of communicating with the other KAVACH within the radius of 5 KM at- least. - Antenna for station/ IBS/ mid-section interlocked Gate unit will be Combination of vertically polarized Omni-directional antenna. - Station KAVACH and Loco KAVACH units communicates with each other for every 2 seconds. - Pair 1 : Station Tx - 456.8 MHz, Rx - 416.8 MHz - Pair 2 : Station Tx - 466.8 MHz, Rx - 426.8 MHz - Common Frequency, f0 - 441.8 MHz 1. ### UHF Radio Modem Requirements (As per RDSO specifications) a. Shall be FCC or IC or CE certified b. Shall possess RTS/CTS and/or DOX modes c. Shall be capable of RF Data Transfer in "Bitwise" / streaming Mode d. RF frequency range:406-470MHz e. RF Channel Bandwidth : 25kHz f. Modes of operation Full Duplex g. Modulation: 2FSK at 19200 bps with linear 8th order low pass filter (raised -- cosine alpha.1Approximation). h. Deviation: 4.3 kHz +/- 0.1 kHz. Occupied Bandwidth :16.35 kHz +/- 0.15kHz i. Operating frequencies : Ranging from 406 MHz to 470MHz j. Emission : according to16K0F2D k. Transmitter freq. stability : 1ppm l. Transmitter Turn-on time (Tx. Freq. stable)/ Channel Switching time: not more than 15msec m. Carrier Output Power: 1-10 w adjustable through software. n. Receiver Adjacent Channel Rejection 70dB at 25kHz 2. ### Receiver Sensitivity: 35 micro-volts for 12 dB SINAD o. 1 x 10-6 BER at -100 dBm Level for 19.2 kbps and 25 kHz Bandwidth p. Interfaces: RS232 q. RF Impedance : 50ohm r. Power Supply : 10V-30V DC s. Set-up and Diagnostic features to be available through separate port RS232 and real time non-intrusive online diagnostics. 3. ### Functional Requirements 1. **Modulation** i. The modulation used shall be 2FSK with 19,200 baud rate with linear 8th order low pass filter (raised cosine alpha 1approximation). ii. Occupied bandwidth shall be 16.35 kHz +/.15 kHz iii. The nominal deviation shall be 4.3 kHz +/-0.1 kHz. 2. **Transmission** i. During bit stream over the air transmission, LSB shall be transmitted first. ii. Transmission shall start within 3ms +/- 1ms after data terminal equipment causes the signal on RTS line to be high. iii. RTS shall be raised before commencement of preamble transmission. +-----------------+-----------------+-----------------+-----------------+ | **DTS** | | **DTS RTS** | | | | | | | | **RTS** | | | | +=================+=================+=================+=================+ | Low | | Low | | +-----------------+-----------------+-----------------+-----------------+ | High | | Low | | +-----------------+-----------------+-----------------+-----------------+ | High | | ↑ | | +-----------------+-----------------+-----------------+-----------------+ +-----------------+-----------------+-----------------+-----------------+ | **DTS** | | **DTS RTS** | | | | | | | | **RTS** | | | | +=================+=================+=================+=================+ | High | | High | | +-----------------+-----------------+-----------------+-----------------+ | High | | ↓ | | +-----------------+-----------------+-----------------+-----------------+ | ↓ | | ↓ | | +-----------------+-----------------+-----------------+-----------------+ Chapter ============================ GSM/ GPRS Communication ----------------------- - Communicating Fault messages to NMS - Transfer of Authentication keys for radio communication between Stationary KAVACH and Loco KAVACH ### Communicating Fault messages to NMS - Radio Communication failure longer than applicable time-out (30 seconds). - Failure of only one radio out of two radios in hot standby in Loco KAVACH. - CPU time and GPS time out of synchronization. - Failure of both -- GPS/GNSS and Real Time Clock (RTC). - Active Cab/Desk DMI communication failure in Loco KAVACH. - RFID reader failure - In Post Trip (PT) Mode or Isolation (IS) Mode. - On receiving Missing RFID Tag information. - Radio Communication failure longer than applicable time-out (30 Seconds). - Failure of only one radio out of two radios in hot standby. - Failure of both GPS/GNSS and Real Time Clock (RTC). - Active Cab/Desk DMI communication failure. ### Transmission of Authentication keys for radio communication between Stationary KAVACH and Loco KAVACH ### Key Management System (KMS) Server - KMS is responsible for distribution of authentication keys to KAVACH systems for radio security. - Communication between Stationary and Loco KAVACH Units is based on AES-128 encryption. - GSM communication is used to transfer Keys to Loco and Stationary KAVACH. - A central KMS server is hosted at Head Quarters to communicate authentication keys to Loco KAVACH and Stationary KAVACH. - Single KMS is sufficient for all Railways. All the stationary KAVACH and Loco KAVACH IDs and SIM card numbers are to be provided to Railtel, to update the same in the KMS. - Communication between KMS and KAVACH is on GPRS and currently being upgraded to LTE. 4. ### Key Definition & Type of Keys 1. **Authentication Key (KA)** 2. **Session Key (KS)** - Session key is used for protection of data transfer between Stationary &Loco KAVACH units. This key will be computed by Loco KAVACH and Stationary KAVACH units at the time of establishment of communication session between Stationary KAVACH unit and Loco KAVACH Unit. - On entering into "Communication mandatory Zone" in vicinity of Stationary KAVACH territory, Loco KAVACH unit sends the Access Request packet to Stationary KAVACH system in "f0" frequency. - Stationary KAVACH unit transmits the Access Authority message with Message Authentication Code (MAC). - Loco KAVACH unit receives the Access Authority message packet with MAC and compute the session key KS. - The MAC will be computed for the Access Authority message packet and verified with received MAC. If the computed MAC matches with the received MAC, Loco starts communicating the regular packet. ### Network Management System (NMS) 1. **Stationary KAVACH to NMS & Stationary KAVACH to Stationary KAVACH Communication on E1 Interface** - KAVACH NMS Network shall be built on E1 interface which is provided by the Indian Railways. Centralized monitoring of a group of stations is achieved by collecting signal aspects, track occupancy, loco absolute position etc., from each of the Stationary KAVACH unit within the network. Network monitoring is limited to its own network. Stationary KAVACH units shall communicate with NMS unit using the predefined packets. - Using E1 interface, each Stationary KAVACH unit is connected to adjacent stationary KAVACH unit/Network Management System to form a network, as shown in below Figure. Using Ethernet protocol over this network, Stationary KAVACH units will exchange Stationary- Stationary communication packets with adjacent Stationary KAVACH units and NMS. - Number of Stationary KAVACH units in one E1 ring shall be limited to 5-7. The IB huts shall be connected to the nearest Station in T network. - In the event of a Radio Communication failure longer than applicable time-out. - In the event of a failure of only one radio of Loco KAVACH, out of two radios in hot standby. - If the incremental difference between CPU and GPS time is not matching and the difference between two GPS is greater than the frame interval. - In the event of failure of both -- GPS/GNSS and Real Time Clock. - In the event of Active Cab/Desk DMI communication failure. 2. **Loco KAVACH to NMS Communication on GSM interface** - In the event of a RFID reader failure (any one or both readers). - To indicate the Loco KAVACH mode to NMS through Stationary KAVACH Unit on encountering any tag (excluding LC Gate Tag), when Loco KAVACH unit is in Post Trip (PT) Mode or Isolation (IS) Mode. - In case of missing RFID Tag information received from Stationary KAVACH. This in turn shall send SMS alert to the Maintenance Staff. - Information to NMS if turn out tag is over read by Loco KAVACH unit. - In the event of a Radio Communication failure longer than applicable time-out (30 Seconds). - In the event of a failure of only one radio out of two radios in hot standby. - In the event of failure of both GPS/GNSS and Real Time Clock (RTC). - In the event of Active Cab/Desk DMI communication failure. 3. **Salient feature of NMS** - Real time display of train movement on NMS monitors. - Offline display of train movement on NMS monitors at Normal, 2x, 4x, 8x, 16x & 32x speed. - Display of Data log in Spreadsheet (Excel Format). - Display of \"Permitted Speed+ Current Speed Vs Location\" and \"Permitted Speed+ Current Speed V/s Time\" including information whether brake command is applied by KAVACH or not. - Ability to watch the NMS at Distant Location through Internet (Password protected) - Ability to extract offline data log through NMS - Generation of Exception Reports - Loco KAVACH Unit-wise, Stationary KAVACH Unit wise, - RFID Tag Set wise. - Prompt through NMS for missing one of the two RFID tags of same set. - Prompt through NMS for missing both RFID tags of same set. - Prompt through NMS for missing communication packets overall below a set level (say 20%) for moving train in Communication mandatory zone. - SMS Alert for repeated same RFID tag missing events in Full Supervision Mode. - SMS Alert for any brake application command by KAVACH Loco forcing train to bring to dead stop in Full Supervision Mode. - SMS Alert for SPAD. - SMS Alert for SPAD Prevention by KAVACH. - Capturing of speed restrictions imposed by TSR Management System from Stationary KAVACH after every update. - Capturing of health status and event log from Loco KAVACH if LTE is available. GPS/GNSS Communication ---------------------- - Time synchronization is very important for seamless data communication among various KAVACH units. Absence of time synchronization often results in error/faults. Multiple Access TDMA scheme is used in KAVACH which requires unified time synchronization. We do not have a Universal Time clock in India, hence we use GPS/GNSS Clock to correct the Real Time Clock (RTC) of any system. - Station/LC/IBS Vital Computer shall have Real Time Clock (RTC) synchronization facility with GPS/GNSS clock to synchronize with other KAVACH systems in hot standby manner. - GPS antenna is installed at the stationary KAVACH unit for time synchronization. Two separate antennas for GPS shall be installed using diverse path for high availability. Diverse make of GPS are preferable to avoid common cause failures. - The Station/LC/IBS Vital Computer RTC should be synchronized with the RTC of all Loco KAVACH Vital Computers and other KAVACH systems. The RTC of all the KAVACH units are set with time reference to GPS/GNSS. - The factors affecting time synchronization are temperature, inferior quality clocks, resource constraints, high density and node failures. When RTC of any Station/LC/IBS KAVACH or Loco KAVACH is not matching with the RTC of other KAVACH units, it synchronizes with GPS/GNSS clock. - When CPU time of Station/LC/IBS KAVACH or Loco KAVACH and GPS time are not synchronized, the time reference shall change to other GPS. - If both GPS are failed, then the system shall work on CPU time for 30 minutes until the situation is stabilized. If there is no stability after GPS time-out, the Loco shall transit out of Full Supervision Mode.  - Accuracy of Time Pulse : 1PPS - Used for time synchronization of KAVACH Radio communication network - Real time events logging - Two GPS modems are used for redundancy - Both GPS are active. Faulty one is detected and isolated in 3 cycles. - Automatic recovery of faulty GPS Chapter ============================ 1. Failures & Fall back procedures ------------------------------- 1. ### Radio communication failures - A radio communication failure shall be deemed to have occurred when 30 seconds for Absolute Block Section and 10 seconds for Automatic Block Section have passed since the last packet received from Stationary KAVACH in communication mandatory zone. - If the last packet received from Stationary KAVACH unit is more than 6 seconds older, the signal aspect and signal description shall be made blank. However, the Loco KAVACH shall continue to function in Full Supervision mode and shall supervise the Movement Authority received in latest packet. - In the event of a Radio Communication failure longer than applicable time-out, the Loco KAVACH unit shall transit from Full Supervision mode to Limited Supervision Mode and if Loco Pilot does not acknowledge within stipulated time Loco KAVACH unit shall apply service brake. In addition, it shall send the message to Network Monitoring System (NMS) through GSM/ LTE. - Stationary KAVACH unit shall send the Fault message to NMS through Ethernet/ GSM/ LTE interface. - In the event of a failure of only one radio when other radio is providing radio communication in hot standby, the Loco KAVACH unit should log the fault. Loco KAVACH Unit shall also send the message to NMS through GSM/ LTE. Stationary KAVACH unit shall send the Fault message to NMS. 2. ### RFID Reader failures - If both RFID readers fail, Loco KAVACH unit should stop radio communication and shall switch to System Failure mode. It shall send the message to Network Monitoring System (NMS) through GSM/ LTE. - In the event of any one RFID reader failure, Loco KAVACH unit should log the event. In addition, it shall send the message to NMS through GSM/ LTE. 3. ### GPS/GNSS failure - Station/LC/IBS Vital Computer shall have Real Time Clock (RTC) synchronization facility with GPS/ GNSS clock to synchronize with other KAVACH systems in hot standby manner. - Incremental difference between the CPU time and GPS time is to be cross checked. If the incremental difference between CPU and GPS time is not matching, the time reference shall change to other GPS. If the difference between two GPS is greater than the frame interval, message shall be sent to Network Management System (NMS). - Diverse make of GPS are preferable to avoid common cause failures. - In the event of failure of both -- GPS/GNSS and Real Time Clock (RTC), the Loco KAVACH unit shall stop radio communication and shall switch to System Failure mode. In addition, it shall send the message to NMS through GSM/LTE. - If the incremental difference is also not matching with second GPS or both systems are failed, then the system shall work on CPU time for 30 minutes, (default, Min: 10, Max: 60) until the situation is stabilized. If there is no stability after GPS time-out, the Loco shall transit out of Full Supervision Mode. - In the event of failure of both -- GPS/ GNSS and RTC, Stationary KAVACH unit should stop radio communication and shall switch to System Failure mode. Fault message shall be communicated to NMS through Ethernet interface. In addition, it shall send the message to NMS either through Ethernet or GSM/ LTE. 4. ### Driver Machine Interface (DMI) communication failures - In the event of Active Cab/ Desk DMI communication failure, Loco KAVACH unit shall switch to System failure mode. In addition, it shall send the message to Network Monitoring System (NMS) through GSM/ LTE. - In the event of Non-Active Cab/ Desk DMI communication failure, Loco KAVACH unit shall log the fault. In addition, it shall send the message to NMS through GSM/ LTE. 2. Protection Functions -------------------- 5. ### Prevention of Signal Passing at Danger (SPAD) - Stationary KAVACH unit shall calculate the movement authority based on the signal Aspect or/and track circuit status, point position and the status of the berthing track circuit. - In case of any conflict between signal aspect, point position, berthing track section, signal aspect sequence and TIN, the Stationary KAVACH unit shall transmit most restrictive aspect of that signal and shall reduce the movement authority accordingly. - Stationary KAVACH unit shall check route information configured on the basis of the KAVACH Control Table of the stationary KAVACH Unit (excluding overlaps). - The off aspect and movement authority for LSS shall be transmitted by Station/ IBS unit only when LSS is off and it is ensured that the concerned Line Clear is available. 6. ### Unusual Stoppage in Block Section ### Protection of Roll Back ### Prevention of Head on & Rear end Collisions in Block Section - Loco KAVACH units either directly or through Stationary KAVACH unit, shall be capable of detecting head on collisions, rear end collisions of trains/locos on single line, multiple lines in all possible scenarios based on the track identification, speed of the trains, train location, train length, train direction movement (Nominal/ Reverse) etc. - In case of head on collision situation, Loco KAVACH units of both the trains shall automatically apply brakes immediately with warning either in Absolute or in Automatic Block Section. - In case of rear end collision situation, Loco unit of only rear train shall automatically apply brakes to bring it to stop short of stipulated distance (300m in block section, configurable) from the train ahead. - In Station sections, Stationary KAVACH shall prevent train collisions with the help of SPAD and TIN conflict. - In case two trains are detected by Stationary KAVACH to be moving towards each other on same TIN in adjacent block section, the SoS command would be generated by Stationary KAVACH for both the trains. On reception of such Loco specific SoS from Stationary KAVACH Unit, the Trains would be stopped through automatic application of brakes. - In case of Multiple locos, the rear end collision message shall be displayed with the details of approaching loco/train only. 9. ### Manual SoS generation/ Cancellation - Loco as well as Stationary KAVACH unit shall have provision of sending SoS message by pressing SoS and Common buttons together. - Loco as well as Stationary KAVACH unit shall have provision to cancel the Manual SoS message by pressing 'Common' and 'ACK/Cancel' buttons together. - When the SoS and Common buttons are pressed simultaneously in Loco or Stationary KAVACH units, the Loco KAVACH units of all the trains/ Locos within 3000m of Location of SoS originating source as well as self-train (if SoS is generated by Loco unit) and approaching towards Location of SoS originating source, shall apply brakes to bring the train/locomotive to standstill before reaching the originating Location of "SoS" message. After the train speed is reduced to zero kmph, train speed shall be supervised for 30kmph (configurable) till the train passes the originating Location of "SoS" message. - SoS sending as well as receiving KAVACH equipment shall log sending & receiving of SoS message. In addition, the information shall be sent to Network Management System by Loco KAVACH through GSM/ LTE and Stationary KAVACH units either through Ethernet or GSM/ LTE. 10. ### Train trip - When a Train in Full Supervision or Limited Supervision Mode passes a stop signal at ON or End of Authority + 30m, the emergency brake shall be triggered. - Operation of the train trip shall be indicated on the DMI. - The emergency brake shall be applied until the Train comes to halt. - When the Train is stationary, the loco pilot shall be required to acknowledge the train trip condition. This acknowledgement will release the emergency brake. 11. ### Auto whistling on approach of Level Crossing Gate - Auto whistling feature on approach of level crossing gate is optional. - Loco KAVACH unit shall display the level crossing gate information (Gate ID) on DMI, when approach of LC Gate is detected through LC Gate Tags. - Loco KAVACH unit shall blow the Loco horn at LC gate, based on the information received from LC gate tag/ SSP. - Loco KAVACH unit shall not blow the horn for LC gate, if movement authority is less than the LC gate distance from its current position. - Continuous whistling shall commence from a distance of 600m on approach of a LC Gate till the time that train reaches LC Gate. Whistling pattern shall be configurable. 3. Protection during transient conditions ----------------------------------------------------------- 12. ### Radio Communication failure - If the communication timeout is longer than 6 seconds, the signal aspect and signal description shall be made blank. However, the Loco KAVACH shall continue to function in Full Supervision mode and shall supervise the Movement Authority received in latest packet. - If Radio Communication failure is longer than 30 seconds, the Loco KAVACH unit shall transit from Full Supervision mode to Limited Supervision mode and shall seek acknowledgement from Loco Pilot. If Loco Pilot does not acknowledge within stipulated time of 15 seconds (Configurable), Loco KAVACH unit shall apply service brake. In addition, it shall send the message to Network Monitoring System through GSM/ LTE. Stationary KAVACH unit shall send the Fault message to Network Management System through Ethernet/ GSM/ LTE interface. - In the event of a failure of only one radio when other radio is providing radio communication in hot standby, the Loco KAVACH unit should log the fault. Loco KAVACH Unit shall also send the message to Network Management System through GSM/ LTE. Stationary KAVACH unit shall send the Fault message to Network Management System. 13. ### Signal goes to danger on approach - When a stop signal on approach is thrown back to danger, and the train in Full Supervision or Limited Supervision Mode passes the stop signal at ON or End of Authority + 30m, the emergency brake shall be applied until the Train comes to halt. - Operation of the train trip shall be indicated on the DMI. - When the Train is stationary, the loco pilot shall be required to acknowledge the train trip condition. This acknowledgement will release the emergency brake. - After the acknowledgement, the loco pilot shall be able to continue the movement in Post- Trip Mode. - Loco KAVACH unit shall supervise the train against a ceiling speed of Post Trip Mode (Default: 15 kmph) and shall exit the Post Trip Mode after crossing the next approaching signal at OFF. 14. ### Signal, point or track circuit, failure Chapter ======= Introduction ------------ i. Voice, Video & Data Communication. ii. Interface requirements of KAVACH over LTE. iii. Mission Critical applications pertaining to Railways. Section proposed for proof of concept ------------------------------------- Scope ----- 1. LTE for Railways consists of User Equipment, Evolved Universal Terrestrial Radio Access Network, Evolved Packet Core with MCX capabilities for Mission-Critical Push To Talk (MCPTT), Mission Critical Data (MC Data) and Mission Critical Video (MC Video) application, normal voice communications. 2. The LTE Functional Requirements Specification defines the requirements of a radio sys-tem satisfying the mobile communications needs of the Indian railways. It encompasses ground- train voice and data communications, together with the ground-based mobile communications needs of trackside workers, station, depot staff and railway administrative and managerial personnel. 3. All voice call services shall be able to operate between any combination of fixed and mobile equipment users. 4. To meet the functionality and performance requirements of LTE, the following system services are required: i. The system shall be designed to work in 700 MHz spectrum (703-748 MHz Uplink & 758-803 MHz Downlink, 3GPP/ETSI Band 28) with 5 MHz (paired) spectrum in the spectrum block 713-718/768-773 MHz Carrier bandwidth allocated to Indian Railways as per Minis-try of Communication, Department of Telecommunication Letter No. L- 14001/01/2019-NTG (pt.) dated 22.10.2021. ii. LTE shall be able to support Frequency Division Duplexing (FDD). The system shall support minimum channel bandwidth of 5 MHz and 25 Transmission Bandwidth configurations (Ref. Doc. No. ETSI TS 136 101 V13). iii. The system shall also support Carrier Aggregation (CA) as per 3GPP/ETSI specification (O). iv. The LTE Radio Network shall be planned with double radio coverage (100% Coverage Overlap) where in case of one eNode-B failure; the adjacent eNode-Bs will cover the requirements. v. The System shall support broadcast based V2V application. V2X application is preferable (Ref. Doc. No. ETSI TS 122 185 V14). These applications are required for Collision prevention by KAVACH, DPWCS and EoTT. vi. MCX should be a completely integrated solution or OTT solution (whichever C-DoT is comfortable with) and support to define MCX aliases for functional addressing (FA) and location dependent addressing (LDA). 5. The EPC is composed of network elements: the Serving Gateway (Serving GW), the PDN Gateway (PDN GW), the MME, PCRF and the HSS. vii. PCRF: It shall apply Gating control, QoS control and Usage monitoring control. viii. Serving Gateway & PDN Gateway: The control plane shall reside near EPC. User planes shall be provided at the Secunderabad and Lingampalli stations in a geo-redundant manner. 4. LTE system requirements ----------------------- 1. Frequency of operation: 700MHZ 2. OFC Backbone: IPMPLS 3. Radio network planning with 30m of coverage on either side of railway track 4. SIP/IMS server for which C-DOT is Comfortable 5. Onboard LTE router modems 6. Interface development with KAVACH at EPC end 7. MCPTT handsets and Dispatcher terminals 8. SIM cards- Approx 50 9. V2V Communication (Preferable) 10. LTE shall support in band and guard operational modes of NB-IoT (O) 5. Network Configuration --------------------- 1. The LTE radio network shall have double radio coverage (100 % overlap), so that if one eNode-B fails, the requirements will be fulfilled by the adjacent eNode-Bs. 2. The E-UTRAN shall provide coverage up to a distance of 30 meters from the nearest running rail in all the directions. 3. The level of coverage should be at least 95% of the time over 95% of the designated coverage area for a radio installed in a vehicle with an external antenna. 6. Functional Requirement of Mobile Equipment ------------------------------------------ 1. ### Cab Radio System 1. Each Train Engine (Loco) shall be provided with 2 nos. of Cab Radio Systems in for Indian Railways front and Rear Loco compartments. The Cab Radio System shall provide mission critical Voice and Data communication for train operational requirements. 2. The Cab Radio System shall work on the spectrum assigned for LTE to Indian Railways. 3. It shall give an audible and visual indication is given that connection to a LTE network was not possible. 4. The Cab Radio System may include the following sub systems: i. LTE Router/ Modem (Central Control Unit) ii. Control Panel (MMI) & Display Unit iii. Microphone & Speaker and MCPTT Handset and Cradle iv. Rail Rooftop Low Profile Antenna v. Dual Redundant Power Supply 5. One Cab Radio System shall consist of at least two Mobile network terminations, in active/ standby configuration i.e. comprising of minimum two mobile equipment and SIM cards. 6. The SIM cards shall be physically integrated with the Cab Radio set and shall not be able to be removed except by maintenance staff. 2. ### Roof top Antenna 7. Separate Rail Rooftop Low Profile Antenna shall be provided for each Cab Radio System. 3. ### LTE Router modem equipment 8. LTE Router modem equipment shall provide interface for the following applications: vi. KAVACH vii. Cab Radio viii. IoT ix. Surveillance 9. The equipment in the Cab and their redundant equipment shall be connected over Optical Fibre Media or any other media of industry standard in Ring Arrangement. 10. The various systems/sub systems in the Cab Radio System for voice and data shall be connected with suitable cables and wires complying with relevant specifications and standards for Rolling Stock Application. 11. The Ethernet interface between Cab Radio and client application shall be on industrial grade fibre or CAT6 cable with suitable M12/M23 connectors. 7. Onboard LTE Router ------------------ 1. ### Over the Air Requirements of Onboard LTE router i. QoS on Uplink shall be on QCI 69 for KAVACH ii. Operating system -- Shall not be from land border sharing countries iii. Support MVB, RS-422, RS-485 (O) iv. Support reception of GPS and IRNSS(O) v. Support Software defined LAN(Virtual LAN) vi. Support SNMP v3 KAVACH LTE Interface Requirements --------------------------------- 1. Each stationary KAVACH (SVK) shall be connected to the PGW of EPC through Railways L3 VPN implemented using IPMPLS existing OFC network. This OFC network shall be of redundant architecture. 2. Each loco shall have provision of redundant LTE radio modems, to which the Onboard KAVACH (OVK) system is connected via IP interface. 3. EPC shall generate dynamic IP addresses to the OVK, which are accessing request to stabilize communication. 4. OVK shall have the URL of KAVACH Application Server (KAS) and Loco Exchange Server (LES). 5. The LTE modem of loco communicates with eNodeB on the wayside over RF. 6. Server random number of two bytes shall be generated whenever the information is passed on by the KAS to OVK. KAS shall be capable of handling IPV4 and IPV6 address. 7. Flow of data from OVK to SVK is detailed below: i. EPC shall allot IP address to OVK dynamically on registration. ii. OVK shall have the URL of KAVACH Application Server. iii. On entering to KAVACH territory, OVK shall communicate its Loco ID and approaching SVK ID to KAS. iv. Based on the approaching SVK ID communicated by OVK, KAS shall communicate applicable IP addresses of Stationary KAVACH, NMS, TSRMS and CTC from the lookup table to OVK. v. Based on the SVK IP address received, the OVK shall request access from the Stationary KAVACH. vi. The SVK shall establish communication with OVK based on the access request packet request received from OVK. vii. With the communication established between SVK and Onboard KAVACH, the communication between them shall take place with SVK to OVK and OVK to SVK regular packets. viii. OVK shall obtain IP address from KAS for establishing communication with next SVK or restoration of a communication failure. ix. The same procedure is to be followed for NMS, TSRMS and CTC. 8. KAS shall pass on the Driving unit/loco ID, its IP addresses and the location details to Loco Exchange Server. 9. Loco Exchange Server2 shall populate a dynamic lookup table of loco IDs and their IP addresses within a geographical region. This geographical region shall cover all the locos with a distance of 5000 m (configurable). 10. Flow of data from OVK to OVK in its vicinity is detailed below: x. Loco Exchange Server shall populate a dynamic lookup table of loco IDs and their IP address within the vicinity of the loco based on the data received from KAVACH Application Server. xi. OVK shall have the URL of Loco Exchange Server. xii. OVK shall communicate its Access Request Packet to Loco Exchange Server through Onboard KAVACH to Loco Exchange Server packet. xiii. Loco Exchange Server shall aggregate the OVK access request packets received from all the locos in the geographical area and send onboard access request packets to each loco in the geographical area through Loco Exchange Server to OVK packet. xiv. OVK shall decode the above information and validate it for SoS and collision scenarios. STATION KAVACH: --------------- 1. What is the maximum size of communication packets between S KAVACH & L KAVACH? 2. What is the FSC input capacity in HBL make Stationary KAVACH? Ans. 32 inputs 3. What for E1 Connection is provided and on what backbone network this E1 circuit will function? 4. What is the communication media between Station KAVACH and SM OCIP? 5. How station KAVACH to station KAVACH connected in 4.0 ver? 6. How Loco KAVACH will communicate with Station KAVACH in a block section of 12 km length without towers in between in 4.0? 1. Which encryption is used between Loco KAVACH and Stationary KAVACH? Ans. AES 128 encryption. 2. If both GPS are failed then what happens to the KAVACH system? 3. What is the maximum size of communication packets between S KAVACH & L KAVACH? 4. What is the size of the cable used for Data for RFID reader and Tachometer? And. 0.5 mm shielded twisted pair cable used 5. How does one loco identify another loco in a non kavach mandatory zone, if both are approaching on the same track and opposite direction? 6. Is quad cable used for Kavach communication or not? Ans. Not used. 7. What are the frequencies used in Kavach UHF communication between station and Loco? Ans. f1 - 456.8 MHz, f2- 416.8 MHz, f3 - 466.8 MHz, f4- 426.8 MHz 8. How will loco to loco communication be held? Ans. In f0 441.8Mhz 1. What type of tower is constructed at HFZ stn. and LPI for Radio connectivity Ans. Self supported Lattice tower 2. What is height of tower at LPI Stn. Ans. 40 meters 3. At what height of tower Radio Modems are placed Ans. 10 meters 4. How many radio modems are placed Ans. Two radio modems 5. From Radio modems to Antenna what type of cable connectivity is provided Ans. Co-axial cables (LN 600) 6. How many cables are provided from Radio modems to Antenna Ans. Four co-axial cables are provided 7. How many antennas are provided on the tower Ans. Four antennas are provided 8. What type of antennas are provided Ans. Dipole Omni directional antenna 9. How many Rx & Tx antennas are provided Ans. Two TX and two Rx antennas 10. What is gain of antenna is dB Ans. 9 dB gain 11. What is Radiated power of antennas Ans. 10 Watts 12. How many power cables are run onto Radio tower Ans. One power cable is run onto radio tower 13. What is the distribution of these power cables 14. How much voltage is needed for radio modems Ans. 24V 15. How tower is protected from Lighting Ans. Lightning arrestor is provided 16. What type of SPD is provided in Radio modems Ans. Class C type SPD is provided 17. What type of earthing is provided for radio tower Ans. Maintenance free earthing 18. The data from Radio modem to Stationary KAVACH is carried using what type of cable Ans. OFC cable 19. What type of OFC cable is laid (Single Mode / Multi Mode) Ans. Multimode cable 20. How many cores (fibres) are there in OFC cable Ans. 6 core 21. Approximate length of OFC cable from Radio tower to Stationary KAVACH Ans. 400 meters 22. How many OFC cables will be laid between tower and Stationary KAVACH? Ans. 2 cables are cables are used 23. What is the distribution of these OFC cables 24. The length of separation between the two OFC cables is Ans. 6 meters 25. How will tower lights (Aviation Lamps) be off during day time? Ans. Aviation lamps will be on and off with the help of light sensors. 26. What is the multiplexing technique used in KAVACH? Ans. TDMS/FDMA 1. IRISET Signaling Notes S-28A -- KAVACH -- Indian Railway Automatic Train Protection System 2. Various articles on KAVACH published in Gyandeep technical magazine of IRISET, Secunderabad 3. RDSO Specification of Kavach (The Indian Railway ATP) No. RDSO/ SPN/ 196/ 2020 - Multiple Access Scheme & Radio Communication Protocol Annexure - C) Version 4.0 d3 Amdt-6 4. RDSO Specification of Kavach (The Indian Railway ATP) No. RDSO/ SPN/ 196/ 2020 -- UHF Radio Modem requirements Annexure - E1) Version 4.0 d3 5. RDSO Functional Requirements Specifications of LTE for Proof of Concept for Indian Railways version 0 d0 May-2022 6. Various technical presentations on KAVACH given by officials of IRISET, Secunderabad 7. PowerPoint presentations on KAVACH of M/s HBL, M/s Medha & M/s Kernex Microsystems -- -- -- -- -- -- -- -- CAMTECH Publications ========================================= Our Objective =============