E4E5 Telecom Factory CHAPTER-18 FAMILIARIZATION OF TELECOM TECHNOLOGIES

Transcription

1 E4E5 Telecom Factory CHAPTER-18 FAMILIARIZATION OF TELECOM TECHNOLOGIES

2 Consumer Fixed Access Network Overview-I The telephone network used for fixed line services is also referred as PUBLIC SWITCHED TELEPHONE NETWORK (PSTN). There are different types of the telephone exchanges or elements (switching systems) in PSTN which work on circuit switching principle. While the data networks, on the other hand use the principle of Packet Switching. In Packet switching the information (speech, data etc.) is divided into packets, each packet containing piece of information also bears source and destination address. 1.0 PSTN Elements The telephone network is consists of various PSTN elements like local exchanges, transient exchanges, local cum transient exchanges, NGN /IP TAX and standalone signaling transfer point (SSTP). These element, consists of new technology switching systems, were inducted in our network. Mainly 4 NT switching systems were inducted in BSNL network: EWSD Supplied by M/s Siemens, Germany OCB-283 Supplied by M/s Alcatel, France 5ESS Supplied by M/s Lucent, USA AXE-10 Supplied by M/s Ericson For rural area in our country where small capacity exchanges were required, CDOT equipment (CDOT 128P, 256P, SBM, MBM etc) was installed. CDOT technology is indigenously developed technology in our country. Initially standalone 128P, 256 P CDOT exchanges were installed but now these small independent exchanges have been converted into AN-RAX (Access Network Rural Automatic Exchange) and they are parented to nearby CDOT SBM/MBM or NT exchange. With this development now all remote ANRAXs can be maintained from the SBM/MBM. It improved O& M functions/issues of small exchanges. In the BSNL network about 30% of the total switching capacity is on CDOT technology. The total equipped capacity in BSNL as on Sept 2010 is about 6, 21, 98,000 (including WLL and DLC). In the BSNL network about 38% of the total working connection is on CDOT technology. The total working connection in BSNL as on Sept 2010 is about 3, 10, 36,276 (including WLL and DLC).

3 The WLL FWT (Fixed wireless terminals and the connection given over DLC are counted in Basic service (Fixed Network). 2.0 Network Organization: The PSTN network is organized in a hierarchical manner with Lev-1/ Lev-2/ Tandem/ Local Exchanges. The calls from a local exchange are routed to Lev-I TAX either directly or through Lev-II TAX. From Lev-I TAX it is routed to the destination exchange either directly or through another Lev-I/Lev-II TAX. For ISD calls ISD Gateway is used. Existing network node:- Lev-I TAX In 21 places Lev-II TAX In 301 Places International gateways at 6 places (Delhi, Chennai, Mumbai, Kolkata Jallundhar and Ernakulam ). Local Exchanges: About 36,000 New network (Upgradation) node:- NGN/ IPTAX (Delhi and Chennai) and other are at the sites of Lev-I TAX. SSTP Interconnection with the private operator: Any operator can take license for providing basic telephone service on circle basis. Licenses are issued by DOT. Once an operator gets a license in a particular circle, after installing the necessary equipment it is required to be interconnected with the BSNL network for making the calls into/from BSNL network. For this either the connectivity is taken at local exchange level for local calls and also at Lev-I/Lev-II TAX for long distance calls. It is called POI (Point of Interconnection). POI charges are prescribed by TRAI. 4.0 NGN Architecture & IP TAX The PSTN network is mainly optimized for voice calls and not much suited for data services. We have a separate network for data services. Today the world over trend is for a single converged network used for all type of services viz. voice, data, video which is called Next Generation Network and is a based on packet switching principle. To change over from current generation network to next generation network we have to move in a step-by-step manner to safeguard our existing network infrastructure and investment and therefore we have to follow an evolutionary path Why NGN?

4 The NGN concept takes into consideration new realities in the telecom industry characterized by factors such as the need to converge and optimize the operating networks and the extraordinary expansion of digital traffic (i.e., increasing demand for new multimedia services, increasing demand for mobility, etc.). The other reasons why we should evolve our existing network to NGN are that the existing circuit switched networks have following problems: Slow to develop new features and capabilities. Expensive upgrades and operating costs. Proprietary vendor troubles Large power and cooling requirements. Limited migration strategy to new tech. Model obsolescence What is NGN? A Next Generation Network (NGN) is a packet-based network able to provide Telecommunication Services to users and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent of the underlying transport-related technologies. It enables unfettered access for users to networks and to competing service providers and services of their choice. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users. < ITU-T Recommendation Y.2001 (12/2004) - General overview of NGN>. ETSI (European Telecommunication Standardization Institute) defines the NGN as a concept for defining and deploying networks, which due to their formal separation into different layers and planes and use of open interfaces, offers service providers and operators a platform, which can evolve in a step-by-step manner to create, deploy and manage innovative services.

5 The following diagram depicts the concept of NGN. Current Gen networks NGN Call Control Call Server Switching IP/MPLS Interfaces Gateways SDH Transport with Overlay packets for data Common IP MPLS Transport over SDH/ DWDM/Fiber Fig. 1 In NGN basically the call control (i.e. signaling) and the switching is separated out in different layers and between these layers open interfaces are used. The call control functionality is realized by a component which is called call server or soft switch or media gateway controller or call agent and the interfaces to the existing PSTN switches is done with the help of media gateways for voice transport and by signaling gateways for signaling transport. For switching and transport of the packets existing IP/MPLS backbone is used. With NGN architecture the new and innovative services can be given very fast and cost effectively. Also the capital expenditure and operational expenditure come down drastically. 4.3 The NGN is characterised by the following fundamental aspects: Packet-based transfer Separation of control functions among bearer capabilities, call/session, and application/service Decoupling of service provision from transport, and provision of open interfaces Support for a wide range of services, applications and mechanisms based on service building blocks (including real time/streaming/non-real time services and multi-media) Broadband capabilities with end-to-end QoS and transparency

6 Interworking with legacy networks via open interfaces Generalized mobility Unfettered access by users to different service providers As the BSNL is having a huge PSTN network consisting of local and TAX exchanges, therefore we have to gradually migrate towards NGN. Initially BSNL has planned to implement NGN at the TAX level and subsequently will be implemented at the local exchange level IP TAX in BSNL IP TAX is the first step towards the evolution of current generation network to next generation network in BSNL. In other words IP TAX is the replacement of existing Level I/Level-II TAX exchanges to IP based network (Packet Switching Network) and rest all the network still remaining circuit switched network. Presently IP TAX will be installed in parallel to the Lev-I TAX and then it will replace circuit switched TAX completely with IP TAX. In BSNL 40K IP TAX at New Delhi and 16K IP TAX at Chennai have been installed. There is a further plan of installing 6476 K IP TAX in all places where Level I/Level-II TAX exchanges are existing. Generic reference diagram for IP TAX is shown in Fig.2. Based on the GR the implementation plan is as below: The IP TAX architecture is planned in the multiple capacities of 200K circuits. The architecture of one 200KC is as below: Setting up two Soft Switches Two or three Signalling Gateways Providing Trunk Media Gateways (TMGs) at different locations with 200KC Capacity. Providing one Announcement Servers in each IP domain i.e. one with each soft switch Billing interface to Centralized Billing Server at Chennai. NMS at Chennai with FCAPS capability. (Fault, Configuration, Accounting, Performance, Security) No separate NTP server is being used in IP TAX, the existing NTP server of our data network will be used for synchronization.

7 Fig Functions of Soft Switch (or Call Agent or Call Server or Media Gateway Controller) Based upon open architecture Provide all existing services available in TDM network Performs media gateway Control function Performs call control, signalling and interworking, traffic measurement and recording functions Provides addressing, analysis, routing and charging facilities Interacts with application server to supply services not hosted on soft switch 5.2 Functions of Signalling Gateway (SGW) Provides interworking function between SS7 network and IP network This involves providing various types of User Adaptations so that the SS7 signalling can be terminated in SGW and can be translated and messages transported over IP Network Performs packetization of signalling and ensures its transport through IP network 5.3 Functions of trunk media gateway (TMG) Performs the functions of Voice encoding & Compression

8 Packetization of voice channels CNF (Comfort Noise Generation) VAD (Voice Activity Detection) Echo Cancellation 5.4 Advantages of IP TAX deployment: One backbone for voice and data services instead of two parallel ones. No maintenance of proprietary switching systems. Fewer call controlling entities in the network so less capital and operating cost. Less space and power requirement. Easier configuration of equipment. 6.0 SSTP (Standalone Signal Transfer Point) 6.1 Need of SSTPs The efficiency of SS7 had made a numbers of applications possible e.g. fast connection setup in PSTN, short message service and location update messages in GSM world. As the size of the network grew, it became more and more difficult to manage the direct SS7 links between the switches and from switches to other network elements like HLR, SMSC, SCPs etc. The introduction of Standalone Signal Transfer Point (SSTP) was a historic step from that perspective. It immediately solved issues related to the complexity by converting the mesh networks into the star networks. It is now possible to handle the signalling very efficiently. This capability also offloads some of the processing power required in the Level-1 TAX and all switches could breathe easier. SSTP also handle the non call related messages efficiently. These messages exist in all the technology and may not be needed to be handled by a switch. Many times these will actually involve multiple technologies and in absence of the uniform signalling layer, the complexity increase many fold. For example a simple service like SMS, a CDMA subscriber may send the message to a GSM subscriber that could go through the long distance network. This involves three different networks and three technologies. However one thing is common, which is signalling as the transport to carry this. The SSTP suddenly became the vantage point in the network because of the simple reason that the signalling protocol was common i.e. SS7, independent of the technology and the access. Be it GSM or CDMA, the connectivity was based on SS7 with different application parts (MAP, INAP etc.). Thus the SSTPs are actually a centralized routing database and not a transmission system for SS7 packet. As the number of subscribers is growing, the number of nodes involved in the routing is also increasing exponentially. If the management of the routing is to be done on these individual nodes, the complexity increases accordingly, which also mean the increased chances of error and hence loosing the revenue. The SSTP,

9 enabling the uniform signalling in SS7 domain, provided a single routing database, which is managed centrally. This routing database is able to make the routing decision based on the destination point codes (DPC), global title translation (GTT), routing keys etc. When any mobile subscriber of a private operator roams into service area of other operator (say BSNL), the signaling traffic or SMS are being handled by signaling channel of BSNL taken by private operator against the POI. BSNL was not able to measure the traffic and it was also not known about the type of signaling traffic. To measure and know type of signaling traffic, SSTP was planned and installed so that billing to private operators can be done accordingly. Due to reasons explained above, BSNL decided to have a separate signalling network by installing a number of SSTPs at various locations. 6.2 Objectives of SSTP s Following were the main objectives:- Regulate, measure, and account for inter-network traffic including SMS messages from mobile networks including GSM and CDMA Achieve a flexibility and transparency in management of signalling for BSNL s wired and wireless networks. Optimal expansion of GSM & CDMA network of BSNL Introduction of new services. Offer CCS#7 & IP Signalling Services to other Wire line & Wireless Network Operators. With the above objectives in mind, BSNL awarded a contract to Ms. ITI for the supply and installation of 10 SSTP nodes in September, Later on, the scope of the project was further expanded to provide 24 nodes in total covering all the major location including all the Level-1 TAX locations. This was a significant step in the direction of the giving the decades old BSNL network an uplift. 6.3 SSTP s at BSNL Network 21 TAX Locations with an STP at each location. Pair of STPs designated as mated pair with identical routing data and complete failover capability. Phase 1-10 Locations Phase 2-11 additional locations: This was later changed to 24 locations to take care of the connectivity issues. 4 Additional locations are Jammu, Shimla, Dimapur, Shillong and dropping Raipur Phase 3 Expansion of all 24 nodes to about capacity of 1800 LSL per node Six STPs are designated as ANSI-ITU MTP gateway (ILD Gateways). Connect multiple SS7 nodes (MSC, Level-1 TAX, Level-2 TAX, Local Exchanges, SMSC, HLR, SCP) to a mated pair using SS7 E1 links. SSTPs interconnected using BSNL s IP/MPLS network on M2PA

10 Later on M3UA functionality is also included to connect the access nodes e.g. Soft switch, GMSC, IN, HLR etc. Centralized Network Management with an Active and DR Standby site Central Billing Server for billing inter-carrier SS7 usage 6.4 Planned Applications on SSTP Network Lawful Intercept of SMS Mobile Number Portability Questions For Assessing Transfer Of Learning Question 1. Explain PSTN organization within BSNL indicating all main types of network elements. Question 2. Limitations of existing circuit switched networks vis-a-vis advantages of NGN. Question 3. Diagrammatically depict the concept of current generation network vis-à-vis next generation network. Question 4. Briefly describe the functions of soft switch in NGN. Question 5. Briefly describe the functions of Signalling Gateway (SGW) in NGN. Question 6. Briefly describe the functions of Trunk Media Gateway (TMG) in NGN.. Question 7. Briefly describe the objectives of SSTP in BSNL. Question 8. Briefly describe the Deployment of SSTPs in BSNL network. Question 9. What are the planned applications of SSTP in BSNL network.

11 CFA Technology Overview-II (Service) 1.0 Introduction BSNL had been the largest telecom operator in India and is known to everybody for Basic Telephony Services for over 100 years. Presently the plain old, countrywide telephone service is being provided through around 36,000 electronic exchanges, 326 places digital trunk automatic exchanges (TAX), digitalized public switched telephone network (PSTN) all interlinked by over 2.4 lakh km of optical fiber cable, with a host of phone plus value additions to our valued customers. BSNL's telephony network expands throughout the vast expanses of the country (excluding Mumbai and Delhi) reaching to the remotest part of the country. Gone are the days when basic telephones were used only to make and receive calls. With the aid of state-of-the-art digital exchanges, BSNL offers a host of phone plus services, converting old basic telephones to a sophisticated tool which can be used for a variety of applications. Most of the phone plus facilities are available free of cost with effect from January 22 nd, Numbering Scheme in BSNL: DoT assigns the initial code for all the operators. BSNL having licenses in all the circle in the whole country except Delhi and Mumbai has been assigned digit 2. The actual number which is dialed by the calling subscriber is prefixed with the SDCA code. At present the SDCA code+ Local no are of 10 digits e.g in Jaipur SDCA the local number is identified as 141 (SDCA Code) (local Number). Some special services like directory enquiry (197), fault booking (198), railway enquiry (139) etc are provided by these standard short codes. 1.2 Services offered by BSNL s Landline: Main service are related to - speech, data, audio & video Supplementary services in PSTN (phone plus services) a. Abbreviated Dialing For registration Dial short code + destination number For use Dial 111+ short code i.e b. Call Waiting For activation of the service dial: 118 (wait for the acknowledgement tone/announcement)

12 For deactivation of the service dial: 119 (wait for the acknowledgement tone/announcement) c. Hot Line A subscriber may want to be connected directly to a pre-determined number as soon as he/she lift the hand set even without dialling. At the same time he/she may want to have the flexibility to dial any other number of his/her choice. d. Call Transfer (Call Forward) For activation Dial 114 and DN for which the call is to be transferred (wait for the acknowledgement tone/announcement). For deactivation dial 115 and wait for the acknowledgement tone/announcement. e. Automatic Wake-Up/Reminder Call Service For entering : Dial (wait for the acknowledgement tone/announcement). For cancellation : Dial 117 (wait for the acknowledgement tone/announcement). f. Number/Call Hunting Service If subscriber have more than one telephone line, this facility is very helpful for caller. If the called line is engaged, caller does not have to disconnect and dial other line(s). This facility automatically transfers the incoming call to whichever line is free. g. Calling Line Identification Presentation (CLIP) To get the calling identity on subs. Telephone set. h. Calling Line Identification (CLI) Announcement Service Dial 164 and listen to the DN of the phone line that you have used to make the call. Very useful when in doubt about your phone number.(subject to technical feasibility) i. Electronic Locking For STD/ISD ( Dynamic Locking Facility) For registration of code (one time only): To register secret code Dial 123 ABCD ABCD then wait for the acceptance tone (ABCD is the secret code chosen by the subscriber)

13 For changing secret code: To change already created secret code Dial 123 ABCD PQRS then wait for the acceptance tone (PQRS is the new secret code chosen by the subscriber) For locking/unlocking with secret code: A subscriber has to dial 123ABCDX (wait for the acknowledgement tone/announcement). Here ABCD is the subscriber s current secret code. X value indicate : 0 STD/ISD open (subject to provisioned by xge.) 1 STD/ISD lock but local call open 2 STD/ISD, Level-9,trunk call booking etc. locked but local call open 3. STD open (subject to provisioned by Xge.) 4. All O/G calls locked j. Call Conferencing With this service telephonic conference can be set up within 3 or more parties. This service is available subject to technical feasibility Services Offered By ISDN:- 1. Normal Telephone & Fax (G3) and G4 Fax 2. Digital Telephone -with a facility to identify the calling subscriber number and other facilities. 3. Data Transmission at 64 Kbps with ISDN controller card 4. Video Conferencing Supplementary Services supported by ISDN 2. Landline VAS Calling Line Identification Presentation(CLIP) Calling Line Identification Restriction(CLIR) Multiple Subscriber Number(MSN) Terminal Portability(TP) Call Hold(CH) Value-added services (VAS) are those services that offer differentiation or a value to the bearer service and the ability for telecom operators to charge a premium price. For a telecom operator s perspective VAS is very important as it is a revenue driver. All the telecom service users want to have many other services over and above the basic service. VAS plays a very important role when the telecom market moves towards saturation level. BSNL as a telecom service provider is providing following value added services over basic service:

14 2.1 Internet Facility: BSNL is providing internet service throughout the entire country (except in New Delhi and Mumbai) under the brand name of "Sancharnet". Sancharnet provides free all India roaming and enables it's users to access their accounts, using the same access code (172233) and user ID from any where in the Country. In order to make internet available throughout the length and breadth of the Country, Internet Dhabas have been commissioned at all the Block Head quarters. BSNL provides the following types of connections to access internet to customer: 2.11 PSTN Dial Up Access BSNL internet service offers flexible options of access plans for PSTN dial-up in various slabs of 25,50,100, 200, 500 and 1,000 hours. With Sancharnet dialup account subscriber get all India roaming advantage which is not available with any other ISP because one can access Sancharnet internet by dialling '172233' from any city in India ISDN Dial Up Access Subscribers can have blazing fast Internet surfing and download speeds in 64 and 128 Kbps ISDN dial up connections. The uniform all India access no. for ISDN access is '172225' Account Free Internet Dial Up Access Based On CLI CLI based internet service is a unique method providing internet service in which the customer can access the internet service from any telephone through dial up. The service allows automatic registration on first LOGIN. The authentication will be based on CLI of the telephone with the password supplied by the caller. The charging is totally usage based and the service is a post paid service like normal PSTN. The billing will be separate based on the duration of use and will be charged to normal telephone bill (CLI based) as internet access charge at the prescribed rate. The service is available in selected cities. The access no. of this service is '172222' in all cities. 2.2 Broad Band Connection Broadband service is based on DSL technology (on the same copper cable that is used for connecting telephone). This provides high speed internet connectivity upto 8Mbps. This is always - on internet access service with speed ranging from 256Kbps to 8 Mbps. 2.2 Sancharnet Card BSNL has also launched "SANCHARNET CARD" recently. The Sancharnet Card" is a prepaid Internet Access Card with following features for customers:

15 Self-register for internet access with your choice of user id Renew your existing Sancharnet Account Wide Range of Internet Access Packages 3. Intelligent Network Services: 3.0 Present IN Set Up In BSNL These IN platforms have been supplied by M/s Alcatel Four general purpose IN (GPIN) platforms are working at Kolkata (345), Lucknow (180), Bangalore (425) and Ahmedabad (233) One mass calling IN (MCIN) platform is working at Hyderabad (424) NT switches are being used as SSP. GPINs are being used to provide all IN services except Tele-voting MCIN is being used for Tele-voting and other IN services except ACC New platforms have enhanced capacity for all IN services Following IN Services Are Offered By BSNL:- 3.1 Free-phone Service (FPH) (Access code : 1800) Or Toll Free Service (TFS) This service gives service users (calling party) the opportunity of calling the service subscriber (called party) free-of-charge via the PSTN by dialing a universal directory number from any part of the country. The call-fee is charged to the service subscriber. By subscribing to this service business, commerce industry and trade organizations can advertise and sell their products and services. Dialling plan: SCP code + XXXXXX SCP code is a three digit code of the concerned SCP from where free phone service has been provided to the service subscriber while XXXXXX is five/six digit free phone number allotted to a service subscriber 3.2 Virtual Card Calling services (VCC) (Access code : 1802) Or Universal India Telephone Card(UITC) Virtual Card Calling service allows a customer to make calls without cash. This service allows users to make calls from any telephone in the network to any destination. It is a powerful pre-paid card for those who are on the move and who do not own a telephone.

16 Virtual card calling service is an access code based service. All virtual card calls are preceded by the access code SCP code. After dialing the access code, the subscriber is prompted to enter a virtual card number. The validation is done at the SCP. After this, subscriber is prompted to enter the destination number. This card is available under the brand name ITC catd. 3.3 Account Card Calling (ACC) (Access Code : 1804) It is a pre-paid card more powerful than VCC having features of renewability and dynamic PIN that make it easy to use and more secure. This service allows customer to make calls from any telephone in the network to any destination. The call charges will be debited to subscriber account number. The originating telephone number will not be charged. Registration fee is Rs.5000/- + Taxes. Card can be renewed by paying additional installment in multiple of Rs.1000/-. The account number is eight digits & PIN is four digits. 3.4 Virtual Private Networks (VPN) (Access code: 1801) The VPN service allows public network operators to provide private network features, e.g. Private Numbering Plan (PNP) and Screening capabilities, using the public network infrastructure. The service subscriber can directly manage and administer his VPN via the Customer Control Feature. VPN is typically used to interconnect geographically distributed PBXs. This service enables the subscribers to form an imaginary network within a real network on existing telephone lines. Corporate and others can subscribe to VPN service i.e. they can have their own VPN network by utilizing the existing telephone lines. VPN subscribers can have their own private numbering plan. The VPN users can make calls inside VPN group, outside VPN group to external numbers or they can use resources of VPN to make calls inside VPN from off-net positions or calls can be made from off-net to external numbers while using VPN resources. Who can subscribe for Voice Virtual Private Network service? Good for institutions, Government departments and businesses. All type of companies, distributors, firms, institutions, housing society etc. e.g. State Bank of India, ONGC, State Police department etc. 3.5 Premium Rate Services (PRM) (Access code: 1867) The Premium Rate service enables service users to access the information offered by the service subscriber against payment of a fee. This is accomplished via the announcement facilities or in direct dialog mode. This way, information can be sold over the telephone. The fee charged to the calling party for using the service is

17 composed of the connection part of the network operator and a part for the information of the service subscriber. The network operator collects the total amount which, based on the call-related data, is split on an agreed-upon key between the service subscriber and network operator. The service subscriber is given a 4-digit PRM number which can be accessed form any where in the network. 3.6 Universal Access Number Services (UAN) (Access Code: 1860) And Universal Personal Number Services (UPN) (Access Code: 1868) This service allows a subscriber to have a universal access number (UAN). All the incoming calls for this number shall be routed to different destinations depending upon the geographical location of the caller, the time, the day, or the date on which the calls are made. Company/ Corporate can assign single access number to their offices located at different places. Based on the network involved in routing the call, the UAN service is divided into two categories: 1) UAN Local: When the calling party and the destination number of UAN are in same city i.e. they have same STD code, the UAN calls are local calls and calling person will be charged at normal local call rates. The dialing plan for UAN Local is : SCP code + 4 (digit UAN No.) 2) UAN National: When the calling party and the destination number of UAN are in different cities i.e. they have different STD codes, the UAN calls are long distance calls and calling person will be charged at normal long distance call rates. The dialing plan for UAN National remains same as UAN local: SCP code + 4 digit UAN No. UAN calls can be charged on full charge basis to calling party or on split basis to calling & called party also. 3.7 Tele-voting Services (VOT) (Access code : 1803, 1861,1862) This service allows conduct of public polls and surveys through normal telephones. It is a boon for TV producers, serial makers, manufacturers, service providers and all others who conduct surveys for their products and services including public opinion on various issues of common interest etc. Dialing plan: There are four options available for tele-voting service:

18 (i) The tele-voting number is kept as a toll free number and subscriber of tele-voting service pays the charges for incoming calls. The numbering/ dialing plan is: SCP code + XX YY where XX will be assigned to subscriber and are fixed while YY are choice digits. (ii) The subscriber of tele-voting service does not pay for the incoming calls and calling party pays for the call charges for participating in the tele-voting by one pulse. The numbering/ dialing plan is: SCP code + XX YY where XX will be assigned to subscriber and are fixed while YY are choice digits. (iii) The subscriber of tele-voting service does not pay for the incoming calls and calling party pays for the call charges for participating in the tele-voting by two pulses. The numbering/ dialing plan is: SCP code + XX YY where XX will be assigned to subscriber and are fixed while YY are choice digits. (iv) The subscriber of tele-voting service does not pay for the incoming calls and calling party pays differential for the call charges for participating in the tele-voting. The numbering/ dialing plan is: SCP code + XX YY where XX will be assigned to subscriber and are fixed while YY are choice digits. 3.8 FLPP (Fixed Line Pre-Paid Telephone) (Access code:,1805,1806) FLPP (Fixed Line Pre-Paid) Service enables a subscriber to make calls from a prepaid account linked to his telephone number. Unlike the prepaid card 'ITC' service, where the authentication is done every time through a 16-digit PIN the authentication of FLPP is linked to his telephone line & the user is not required to dial the Account number/ PIN for authentication making it simpler to use. Advantages of Fixed Line prepaid service offers: Conversion of fixed line to Pre Paid and get rid of telephone bills. Easy de-linking from telephone line when prepaid is not required No need to dial Account number/ PIN every time you make a call. STD/ISD Facility On Line balance enquiry Easy recharge and no problem of bills Free Level 1 service like 100, 101, 102 etc. available. Free Level 1 IN services which are free to end-customers like Free Phone etc. are available.

19 There can be four types of FLPP accounts namely PCO FLPP Account, PCO Local FLPP Account, General FLPP Prepaid Account and General FLPP Prepaid + Post paid Account. Presently this service has been started on PCO and on post paid numbers as General FLPP+ Post paid account. 3.9 Call Now Cards: It is a normal ITC card but specifically designed tariff to suit the requirement of users making heavy International/STD calls. Dialling procedure and features are same as that of ITC but the tariff is different from ITC and also different for different denomination of Call Now cards Personalised Ring Back Tone Service: This service is just like the caller tune service in mobile phones. The landline subscribers can also set the ring back tone to be heard by the calling customer as per his choice. 4. Multi-play Multi-play service allows the customer to have data, video and voice service on the same line. The video service can be IPTV (broadcast) and video on demand. This service was launched in Pune and now available in all main cities. 5. Audio Conferencing Audio Conferencing service allows multiple participants to converse with each other regardless of their location through the normal fixed line telephone or cellular phone. An audio conference subscriber can add two or more participants in a particular conference. The customers can schedule their audio conferences through the Web or through IVR. The service is available to existing BSNL subscribers only. Conference can be scheduled one time or standing. A standing conference is always on. The authorized participants have just to dial in a particular telephone number followed by a password to enter into a conference. On demand conference can be made. The chairperson can invite several users one by one in the conference without using the web. 6. Video Conferencing Video Conferencing service allows multiple participants to converse with each other regardless of their location through the video end-points or personal computers.

20 It involves video and audio communication. A video conference subscriber can add two or more video participants in a particular conference. The customers can schedule their video conferences through the Web. The video conferencing service can be availed by any user through IP or ISDN interface. The service is available to existing BSNL subscribers only. Personal computer user can download the software called "PVX" from BSNL's Video Conferencing Portal to avail the Video Conferencing facility with their web-cam. 7. Short Message Service: SMS can be send and received through landline telephones. For this the subscriber will have to purchase a SMS enabled handset. 8. Online Billing Enquiry and Payment Online billing enquiry and payment service is made available by BSNL for many cities where one can see the status of telephone bills as well as pay the bills online. 9. Centrex Service: Centrex is a communication service which integrates a subscriber s all multi located telephone lines (Existing and New) into a single highly functional communication group with more distinctive features without any additional equipment (like EPABX) at the subscriber s premises. A group of subscriber or a subscriber having two or more telephone connections can avail this service in which a centrex group will be formed. All the calls made between the members of the group will be free of charge and are made by using a short code consist of last 2-5 digits (maxi.) of their number. But all the calls made outside the group will be charged at the normal applicable tariff. In a way centrex facility is like having a PBX like facility between the numbers which are geographically distant away in a city without owning a PBX and maintaining it. 11. Answering Machine Service: On the landline numbers answering machine service can be provided by the centralized equipment installed at the exchange. The subscriber can divert his/her calls to answering machine in case of no reply or busy to record some messages and later on he/she can take the messages from the answering machine Service: On landline numbers by dialling the subscribers can have many types of services like:

21 Latest Bollywood songs Old classic songs Jokes Horoscope International/National news Cricket news Different contests Finance/stocks related news Travel information etc Different services can be added /deleted from time to time as per the agreement with the third party content provider. Questions For Assessing Transfer Of Learning Question 1. Write short note on numbering scheme in BSNL. Question 2. What are the supplementary services available to a landline subscriber with and without access codes? Indicate their code for activation/de-activation etc.? Question 3. What are the additional supplementary services available to any ISDN subs? What are the different types of landline VAS available to any subscriber for using internet? Question 4. What are the different types of landline VAS available to any subscriber for using internet? Question 5. Name the cities where IN plate-form are working in BSNL with their SCP code. List out the different IN services offered by BSNL with their access codes and dialing plan.. Question 6. What are the different types of FLPP service and their advantages? Question 7. Compare the feature of ITC card and Call Now card. Question 8. Write short note on Centrex Service. Question 9. What are the different types of FLPP service and their advantages? Question 10. Critically examine service provided by BSNL.

22 OVERVIEW of CDMA TECHNOLOGY The CDMA air interface is used in both 2G and 3G networks. 2G CDMA standards are named as CDMAone includes IS-95A and IS-95B. Systems based on IS-95 standards have lots of the limitations as Spectral efficiency, low data speed, limited roaming, no multimedia, asymmetric data rate etc. Therefore Qualcomm proposed another CDMA standard as IS-2000 with different releases and commonly known as CDMA x networks. IS-95A was the first CDMA system commercially used for cellular networks. The next evolution was IS-95B which provided higher data rate of 64 Kbps instead of maximum of 14.4 Kbps in IS-95B. CDMA x systems are a major evolution over IS-95 standards where much improvement has been done in radio reverse link. In CDMA x systems an attempt has been made to make reverse link more synchronous by adding a pilot in reverse link to reduce interference. This reduced interference leads to enhanced system capacity over the same carrier of 1.25 MHz which is approximately 35 channels/sector/fa as compared to 27 channels/sector/fa in IS-95 systems. A separate Packet Core Network (PS-CN) takes care of data calls. Enhancements of CDMA x over IS-95 are Enhanced Voice Capacity Better handling of packet data CDMA2000 1x Network Architecture: PST N Ex. E1 Link MSC HLR VL R AU C E1 Lin k BSC BSC CS-CN (Circuit Switched Core Network) PS-CN (Packet Switched Core Network) RAN (Radio Access Network) BTS BTS PDSN F A BTS BTS Circuit Switch Core Network Interne CDMA x Network Architecture is divided t in to three parts. World FWT/HHT AAA Server HA HA.. FWT/HHT Packet Switch Core Network

23 Circuit Switched Core Network: This section is dedicated for voice communication and also for wireless authentication. This section includes four parts MSC (Mobile Switching Center): It is responsible for setting up, managing and clearing connections as well as routing the calls to the proper user & provides the network interfaces, the charging function and the function of processing the signaling. HLR (Home Location Register): It is a static database. It has information of a subscriber like ESN, MDN, IMSI, MIN, service information and valid term. It also stores the mobile subscriber location (MSC/VLR address), to set up the call. VLR (Visitor Location Register): VLR is a dynamic database. It stores all related information of mobile subscribers that enter its coverage area, which enables MSC to set up incoming and outgoing calls. When the subscriber leaves this area, it should register in another VLR, and the previous VLR will delete all the data about this subscriber. AUC (Authentication Center): It is an entity to prevent illegal subscribers from accessing CDMA network. It can generate the parameter to confirm the subscriber s identity. Packet Switched Core Network: To provide better connectivity to the internet a new core network i.e. PS-CN is introduced to the CDMA x network. This section includes four parts. PDSN (Packet Data Serving Node): Packet Data Serving Node (PDSN) provides the function of routing of data between Radio Access Network (RAN) and internet. It does all the processing related to the data services. AAA Server: PS-CN also has the responsibility to authenticate, authorise and account for the CDMA 2000 subscribers wishing to obtain packet data services & to fulfil these task PDSN requires support of AAA server. Home Agent/ Foreign Agent Server: HA & FA server is used when mobile IP services are supported by CDMA 2000 PDSN. Key Features of CDMA x: CDMA 2000 has fundamental requirement to maintain compatibility with IS-95 air interface. This means that IS-95 handsets will continue to work in CDMA 2000 network as well as CDMA 2000 mobiles will work in IS-95 network. This is the key aspect of providing a cost effective solution for 2G operators to gracefully upgrade to 3G networks and completely new network and new mobiles are not required. Faster Forward Power Control: CDMA x standard has a faster power control compare to IS-95 counterpart. The power control is done every 1.25 ms.

24 New Radio Configurations (RC): It support Radio configuration RC1 to RC9 in Forward Link and RC1 to RC6 in Reverse link. Radio configuration defines Rate Set, Spreading Rate, Channel Coding (Turbo or convolution), channel coding rate for forward or reverse traffic channel. Variable length Walsh Codes: CDMA 2000 uses variable length Walsh codes of length 4 to 128 to support variable data rate. Higher data rate channels uses shorter length walsh codes and vice versa. Efficient use of spectrum: CDMA2000 technologies offer the higher voice capacity and data throughput using the least amount of spectrum, lowering the cost of delivery for operators and delivering superior customer experience for the end users. Seamless Evolution Path: CDMA2000 has a solid and long-term evolution path which is built on the principle of backward and forward compatibility. Flexibility: CDMA2000 systems have been designed for urban as well as remote rural areas for fixed wireless, wireless local loop (WLL), limited mobility and full mobility applications. It also supports R-UIM for open market handsets. High-Speed Data: Release 0 supports bi-directional peak data rates of up to 153 kbps and an average of kbps in commercial networks in a 1.25 MHz channel. Release A can deliver peak data rates of up to 307 kbps. CDMA x EV-DO: Although IS-2000 is already capable of meeting the 3G data rate requirement of 2 Mbps, Qualcomm proposed a new standard 1xEV-DO in March of 2000 as another option that supports high-rate data services. 1x EVDO (1x Evolution for Data Optimized) is optimized for delivering high speed IP wireless data to many mobile and stationary terminals running multiple applications. EVDO is designed for an always on user experience. The standards for Ix EVDO are defined as IS-856. Salient features of EV-DO EV-DO uses both CDMA and TDMA. Uses its own dedicated 1.25 MHz carrier. No power control on forward link is required. EV-Do has two versions as Rel. 0 & Rev. A. RF system components may be shared with 1xRTT. EV-DO Reverse Link and Forward Link Data Rates IS-856 Rel. 0 Forward Link Variable Data Rates ranges from 38.4 Kbps to 2.4 Mbps IS-856 Rev-A extends this to 3.1 Mbps IS-856 Rel. 0 Reverse Link Data Rates ranges from 9.6 Kbps to Kbps

25 IS-856 Rev-A extends this to 1.8 Mbps. Services in CDMA: BSNL is providing the following services using CDMA technology. Voice SMS Packet data (144 Kbps / 2.4 Mbps) NIC and EV-DO cards: Provided by P200 PDSS installed at Noida, Vadodara, Bangalore and Kolkatta. CRBT: Provided by CRBT Platform. Prepaid: Provided by Wireless Intelligent Network installed on zonal basis at Vadodara, Bangalore and Kolkatta. Bank ATM / Branch ATM Connectivity: A very good business opportunity form bank ATMs and provided by using CDMA network with MPLS backbone together. R-UIM (Removable User Interface Module): It is like a SIM card as in GSM and used for open market handsets. It makes the subscriber independent to the operator s handset. R-UIM is both 1x and EV-DO enabled. OVERVIEW of WiMAX TECHNOLOGY Introduction The WiMAX (Worldwide Interoperability for Microwave Access) technology, based on the IEEE Air Interface Standard is rapidly proving itself as a technology that will play a key role in fixed broadband wireless metropolitan area networks. In December, 2005 the IEEE introduced the e which adds the features and attributes to the standard necessary to support mobility. Mobile WiMAX is a broadband wireless solution that enables convergence of mobile and fixed broadband networks through a common wide area broadband radio access technology and flexible network architecture. The Mobile WiMAX Air Interface adopts Orthogonal Frequency Division Multiple Access (OFDMA) for improved multi-path performance in non-line-of-sight environments. Scalable OFDMA (SOFDMA) is introduced in the IEEE e to support scalable channel bandwidths from 1.25 to 20 MHz. Mobile WiMAX will cover 5, 7, 8.75, and 10 MHz channel bandwidths for licensed worldwide spectrum allocations in the 2.3 GHz, 2.5 GHz, 3.3 GHz and 3.5 GHz frequency bands. The WiMAX Forum brings together leaders in the communication and computing industries to drive a common platform for global deployment of IP based wireless broadband services. The WiMAX forum certifies products for conformance and interoperability based upon IEEE standards. WiMAX forum has various working groups as follows.

26 Network Working Group (NWG) is developing the higher-level networking specifications for Mobile WiMAX systems beyond what is defined in the IEEE standard that simply addresses the air interface specifications. Some of the salient features supported by Mobile WiMAX are High Data Rates: Mobile WiMAX technology to support peak DL data rates up to 63 Mbps per sector and peak UL data rates up to 28 Mbps per sector in a 10 MHz channel. Quality of Service (QoS): WiMAX defines Service Flows which can map to different service code points that enable end-to-end IP based QoS for different types of services. Scalability: Mobile WiMAX technology designed to be able to scale to work in different channelization from 1.25 to 20 MHz to comply with varied worldwide requirements. Security: The features provided for Mobile WiMAX security aspects are EAP (Extensible Authentication Protocol) based authentication, Support for a diverse set of user credentials exists including Digital Certificates, and Username/Password schemes. Mobility: Mobile WiMAX supports full mobility for all types of CPE. WiMAX forum Profiles are defined by the following parameters: Spectrum band Duplexing-TDD/FDD Channel bandwidth End-to-End WiMAX Architecture The IEEE only defined the Physical (PHY) and Media Access Control (MAC) layers in WiMAX Forum s Network Working Group, which is focused on creating higher-level networking specifications for fixed, nomadic, portable and mobile WiMAX systems beyond what is defined in the IEEE standard.

27 The Mobile WiMAX End-to-End Network Architecture is based on an All-IP platform. The use of All-IP means that a common network core can be used. The architecture is based on a packet-switched core network. WiMAX Forum has identified a WiMAX Network Reference Model (NRM) that is a logical representation of the network architecture. The NRM identifies functional entities and reference points over which interoperability is achieved between functional entities. Figure illustrates the NRM, consisting of the following logical entities: MS, Access Service Network (ASN), and Connectivity Service Network (CSN) and clearly identified reference points for interconnection of the logical entities. WiMAX Network Reference Model The Access Service Network (ASN) It provides the connectivity between CPE (or MS) and CSN. The Connectivity Service Network (CSN) is defined as a set of network functions that provide IP connectivity services to the WiMAX subscriber(s). A CSN may comprise network elements such as routers, AAA proxy/servers, user databases and Interworking gateway devices. Physical Layer Description: Orthogonal Frequency Division Multiplexing (OFDM) is a multiplexing technique that subdivides the bandwidth into multiple frequency sub-carriers. In an OFDM system, the input data stream is divided into several parallel sub-streams of reduced data rate and each sub-stream is modulated and transmitted on a separate orthogonal sub-carrier. In OFDM the time and frequency resources can be organized into sub-channels for allocation to individual users. Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple-access/multiplexing scheme that provides multiplexing operation of data streams from multiple users onto the downlink sub-channels and uplink multiple accesses by means of uplink sub-channels.